jo0ls' .Net stuff

Reading CD-Text with VB.Net (3)

2011-10-09T20:34:00.001+01:00

Last time we had retrieved a big blob of data that holds the CD-Text. The mmc3 document tells us the blob is a series of CD-TEXT Pack Data, which we can call packs for short. All the information is contained in these packs, but the packs themselves describe a more complicated data structure that we need to recreate. I used the mmc document, patent application and open source projects to understand this structure.

All the text is stored in one Text Group, which is what we have retrieved. The text group contains up to 8 Blocks numbered 0 to 7. It is possible for a CD to have text in multiple languages, each Block contains text in one language only. Each Block is made up of Packs. A block can contain up to 255 Packs, each pack in a block will have a unique Sequence Number 0-255. If the text is particularly large then it may need multiple blocks to fit it all in. (One block contains text for one language only, one language may require multiple blocks.)

Each pack is 18 bytes in size and has three sections – a 4 byte header, 12 bytes of data and 2 bytes for a CRC. The header of a pack contains it’s block number. The header has one byte to hold the sequence number. The header also contains a number that identifies the type of data that the pack stores. For example the pack type &H80 means the data portion of the pack contains text data forming part of the album or track titles. As it’s only 12 bytes of data in a pack, you might need several packs to describe, say, the title of track 3. The track number is also stored in the header, track number 0 is special and means the data relates to the CD as a whole rather than a particular track. For the Title pack type, for example, track number 0 is the title of the album.

An important pack type is the size pack type. Each block has 3 size packs. These do not contain text data, instead the bytes map to various counts and other numerical information. The size packs describe a block’s:

character code - how the text data in the pack types that store text is encoded. E.g. ASCII
first track number, last track number
copy protection info
number of packs of each pack type in the block
last sequence number of each block (0 if the block number is not used, this information must be repeated in each block as it’s not specific to the block that contains the size packs)
language code – this tells us which language the block is for e.g. English, Afrikaans, French etc.

Most of the packs contain text information for the tracks or album. If we have an imaginary CD which has 3 tracks with title data for each track and the album, e.g:

Album title = “Hello World Album” (Track 0)
Track 1 = “I’m the urban spaceman”
Track 2 = “The intro and the outro”
Track 3 = “Poisoning pigeons in the park”

Then we would split each string up into chars and append a Chr(0) to indicate the end of that string. We chop it into 12 byte sections and make a pack for each section. This table shows the 18 bytes of a pack, 4 (H)eader bytes, 12 (D)ata bytes and 2 (C)rc bytes. /0 indicates a Chr(0). The first header byte is the pack type – for us &H80. The second header byte contains 7 bits identifying the track number (there’s another bit which we are going to say isn’t set). As the data might contain sections of information from multiple tracks, the track number identifies which track the first byte of track data belongs to. The block sequence number is in the third header byte – let’s imagine that these packs happened to start at block sequence number &H10. The eight bits of information in the fourth header byte encode three things – whether the text uses 1 byte or two per character, the block number (0 – 7) and the position that the first character in the data takes in it’s string. The character position isn’t useful to us (maybe it is useful in C or ASM). Let’s ignore this byte, and the Crc bytes, and just assume it’s all in one block.

‘

There are various pack types like this – for the title, performer, songwriter, composer, arranger, messages. There are also other pack types which contain other types of information, like the size pack type. For example, there are pack types for CD Information, Toc information and Genre information. These are always encoded in ASCII, and they are not encoded individually for each language on a multi-language CD.

I imagine that multi-language CDs don’t exist in the wild. When testing burning apps I found none of them would use multiple blocks either. It seems most CDs then will just have 1 block, 1 language and use ASCII, which makes it pretty easy to decode a CD. I’m not exactly sure what happens if you have to split a language over blocks. I guess it just picks up where the last one left off.

In .Net we can have some class CdText to store the properties that apply to the cd as a whole. Then it’s probably easiest to shove the language based information into a datatable. Here we have a primary key of (Language, Track No), and columns for things like Title, Performer, … etc. We can stick some helper properties onto the main class to list the available languages etc.

Reading CD-Text with VB.Net (2)

2011-09-17T00:32:00.001+01:00

I mentioned, in the first part, that there are two control codes that you can send to get the CD-Text bytes back. We’ve used IOCTL_CDROM_READ_TOC_EX and now it’s the turn of the slightly trickier IOCTL_SCSI_PASS_THROUGH_DIRECT. This one lets us send any message we like to the device. To learn about the messages that you can send, you need to get your hands on a copy of the standard specification that defines them all. Hardware manufacturers are supposed to conform to the standard so that all the devices understand the same commands.

The standards of interest are the ones for scsi devices. You have to pay for access to the latest standards, and it looks like access to the ftp for draft standards is now restricted. The old standards are available on the internet in various places though. I still have my copies of mmc3r10g.pdf and spc2r20.pdf. It has some information that will come in handy later about the format of the bytes we have been retrieving. You can find yet more information on this format by looking at open source projects such as cdrdao, the original patent application by Sony and various other projects. The real standard is the Red Book (IEC 60908), but that costs £200 to access.

Anyway, we have to call DeviceIoControl with this other command code. We send it a structure that will contain a cdb (command data block) along with a buffer to contain the bytes that are coming back, and another buffer for so called sense-information. Sense information is helpful as it contains error information – and there are many things that can go wrong – tray out, no cd, DVD inserted, drive not ready, etc. This is probably the only reason to use this message over the other one – you can get back the sense information. It’s also useful to know how to send any command as there are a lot of them in the specification, and they don’t all have an equivalent “friendly” IOCTL code.

The command we are sending is the READ TOC command, the cdb is just 10 bytes in size. It contains one byte for the command code (&H43). Then a byte we can ignore. Then there’s a byte that holds the format. This is the same thing as the format we send with IOCTL_READ_TOC_EX – we can specify different values to get different TOC information. Again, we want to set this to 5 to retrieve CD-Text (see the spec). After that there are reserved, and inapplicable bytes (given the format). At the end there are two bytes to say how big our buffer is, and finally a control byte.

The cdb and a pointer to the databuffer go into a SCSI_PASS_THROUGH_DIRECT structure. This structure is then placed inside another structure that also holds the sense buffer. SCSI_PASS_THROUGH_DIRECT looks like this:

<StructLayout(LayoutKind.Sequential)>

Friend Structure SCSI_PASS_THROUGH_DIRECT                           ' x86   x64

    Public Length As Short                                          '  0      0

    Public ScsiStatus As Byte                                       '  2      2

    Public PathId As Byte                                           '  3      3

    Public TargetId As Byte                                         '  4      4

    Public Lun As Byte                                              '  5      5

    Public CdbLength As Byte                                        '  6      6

    Public SenseInfoLength As Byte                                  '  7      7

    Public DataIn As CommandDirection                               '  8      8

    Public DataTransferLength As Integer                            ' 12     12

    Public TimeOutValue As Integer                                  ' 16     16

    Public DataBuffer As IntPtr                                     ' 20     24

    Public SenseInfoOffset As Integer                               ' 24     32

    <MarshalAs(UnmanagedType.ByValArray, SizeConst:=16)>

    Public Cdb() As Byte                                            ' 28     36

    '                                                        Size     44     56

    Public Shared Function GetSize() As Integer

        Return Marshal.SizeOf(GetType(SCSI_PASS_THROUGH_DIRECT))

    End Function

End Structure

I’ve got the offsets/sizes that I calculated in C in the comments. You can see that the IntPtr field is larger on x64. Here the cdb array is marshalled as a ByValArray which tells the marshaller to stick the bytes directly into the memory of the structure. The alternative is for the bytes to live elsewhere and for the field in the structure to be a pointer to them. We have to fill in this structure, which means we have to know what the PathId, TargetId and Lun of the CD drive are. We can get those with IOCTL_SCSI_GET_ADDRESS. The SenseInfoLength is 32. The SenseInfoOffset can be calculated at runtime using Marshal.OffsetOf to get the offset of the sense buffer in the outer structure (see attached project) – it will vary on x86 and x64.

As before, we’ll call once with a data buffer of size 2. On return, our data buffer will contain the size of the data (excluding the field that holds the size itself). So we can then allocate precisely as much memory as is required to hold the whole CD-Text.

Option Strict On

Option Explicit On

Imports CdTextIoCtl.NativeMethods

Imports Microsoft.Win32.SafeHandles

Imports System.ComponentModel

Imports System.IO

Imports System.Runtime.InteropServices

Imports System.Text

Public Class CdTextRetriever

    Public Shared Function GetCdText(driveInfo As DriveInfo) As Object

        Dim cdText As Object = Nothing ' don't know what the return will look like yet.

        Dim devicePath As String = String.Format("\\.\{0}:", driveInfo.Name(0))

        Const FILE_ATTRIBUTE_NORMAL As UInteger = &H80

        Const GENERIC_READ As UInteger = &H80000000UI

        Const GENERIC_WRITE As UInteger = &H40000000

        Const FILE_SHARE_READ As UInteger = 1

        Const FILE_SHARE_WRITE As UInteger = 2

        Const OPEN_EXISTING As UInteger = 3

        Using hDevice As SafeFileHandle = NativeMethods.CreateFile(devicePath,

                GENERIC_READ Or GENERIC_WRITE,

                FILE_SHARE_READ Or FILE_SHARE_WRITE,

                IntPtr.Zero, OPEN_EXISTING,

                FILE_ATTRIBUTE_NORMAL, IntPtr.Zero)

            If hDevice.IsInvalid OrElse hDevice.IsClosed Then Throw New Win32Exception

            ReadCdText(hDevice)

        End Using

        Return cdText

    End Function

    Private Shared Sub ReadCdText(hDevice As SafeFileHandle)

        Dim address As SCSI_ADDRESS = GetScsiAddress(hDevice)

        ' like in the other program...get the length

        Dim bytes(1) As Byte

        GetCdTextBytes(hDevice, address, bytes)

        ' again we add 2 for the length parameter itself so it's length - 1 + 2 to size the array

        bytes = New Byte((CType(bytes(0), Integer) << 8) Or bytes(1) + 1) {}

        GetCdTextBytes(hDevice, address, bytes)

        Dim sb As New StringBuilder

        For i As Integer = 4 To bytes.Length - 19 Step 18

            For j As Integer = 0 To 17

                sb.Append(bytes(i + j).ToString("X2"))

                If i = 3 OrElse i = 16 Then sb.Append("  ")

            Next

            sb.AppendLine()

        Next

        My.Computer.FileSystem.WriteAllText(IO.Path.Combine(My.Computer.FileSystem.SpecialDirectories.MyDocuments, IO.Path.GetRandomFileName), sb.ToString, False)

    End Sub

    Private Shared Function GetScsiAddress(hDevice As SafeFileHandle) As SCSI_ADDRESS

        Dim address As New SCSI_ADDRESS

        Dim bytesReturned As Integer

        Const IOCTL_SCSI_GET_ADDRESS As Integer = &H41018

        Dim result As Boolean = NativeMethods.DeviceIoControl(hDevice,

                IOCTL_SCSI_GET_ADDRESS, IntPtr.Zero, 0, address,

                SCSI_ADDRESS.GetSize, bytesReturned, IntPtr.Zero)

        If result = False Then Throw New Win32Exception

    End Function

    Private Shared Sub GetCdTextBytes(hDevice As SafeFileHandle, address As SCSI_ADDRESS, bytes() As Byte)

        Dim bytesReturned As Integer

        Dim sptdwb As New SCSI_PASS_THROUGH_DIRECT_WITH_BUFFER

        Dim pinnedBytesHandle As GCHandle = GCHandle.Alloc(bytes, GCHandleType.Pinned)

        sptdwb.ScsiPassThroughDirect.cdb = New Byte(15) {} ' The cdb as described in the standard

        sptdwb.SenseBuffer = New Byte(31) {}

        sptdwb.ScsiPassThroughDirect.Length = CShort(SCSI_PASS_THROUGH_DIRECT.GetSize)

        sptdwb.ScsiPassThroughDirect.CdbLength = 10

        sptdwb.ScsiPassThroughDirect.DataIn = CommandDirection.SCSI_IOCTL_DATA_IN

        sptdwb.ScsiPassThroughDirect.DataTransferLength = bytes.Length

        sptdwb.ScsiPassThroughDirect.DataBuffer = pinnedBytesHandle.AddrOfPinnedObject

        sptdwb.ScsiPassThroughDirect.TimeOutValue = 10

        sptdwb.ScsiPassThroughDirect.SenseInfoOffset = Marshal.OffsetOf(GetType(SCSI_PASS_THROUGH_DIRECT_WITH_BUFFER), "SenseBuffer").ToInt32

        sptdwb.ScsiPassThroughDirect.SenseInfoLength = 24

        sptdwb.ScsiPassThroughDirect.PathId = address.PathId

        sptdwb.ScsiPassThroughDirect.TargetId = address.TargetId

        sptdwb.ScsiPassThroughDirect.Lun = address.Lun

        ' CDB is set with the READ_TOC command

        sptdwb.ScsiPassThroughDirect.cdb(0) = &H43

        sptdwb.ScsiPassThroughDirect.cdb(2) = 5

        sptdwb.ScsiPassThroughDirect.cdb(7) = CByte((bytes.Length >> 8) And &HFF)

        sptdwb.ScsiPassThroughDirect.cdb(8) = CByte(bytes.Length And &HFF)

Try

            Const IOCTL_SCSI_PASS_THROUGH_DIRECT As Integer = &H4D014

            Dim result As Boolean = NativeMethods.DeviceIoControl(hDevice,

               IOCTL_SCSI_PASS_THROUGH_DIRECT,

               sptdwb,

               Marshal.SizeOf(sptdwb),

               sptdwb,

               Marshal.SizeOf(sptdwb),

               bytesReturned,

               IntPtr.Zero)

            If result = False Then Throw New Win32Exception

        Finally

            pinnedBytesHandle.Free()

        End Try

    End Sub

End Class

So, that’s another way to read the same bytes. I’ve told this one to save a file with a dump of the bytes into MyDocuments. It splits the data into lines with 18 bytes on each. It starts at byte 4 to skip the length and two other bytes which appear before the Pack Data. Pack Data contains 12 bytes of information each with a header describing the information and a 2 byte CRC code at the end. Most of the information will be ascii text, although some packs don’t contain text. The header contains a pack type code which has things like Title, Songwriter, etc. It also has values to identify the track number that the data is for. It’s quite a simple format, but tricky to decode without a precise definition of the format! These projects are a bit naff – I’ve not used VS2010 much and it’s messing up my solution with 2 projects in. I can’t seem to get it so that you can switch easily between x86 and AnyCpu builds, so it ends up in mixed mode. You can just start a new empty solution and add the relevant bits if it wont build and run.

Next time I’ll decode the bytes, check the crcs and the sense information. I’ve found that occasionally I get some corrupt data coming in the first time it reads – hopefully the CRC will fail and I can retry.

Reading CD-Text with VB.Net (1)

2011-09-11T21:44:00.001+01:00

Note: most commercial CDs do not have any CD Text on them.

There are probably a few ways to read the CD Text. I’m going to look at using the windows api function DeviceIOControl function. The steps are (1) Get a device handle (2) Prepare a message (3) Send the message to the device (4) Decode the results.

To get a device handle, you call CreateFile sending the drive letter of the drive formatted as a device path. You also have to specify the minimum permissions you will be needing for the operations you will be performing. If you fail to ask for a handle with sufficient permissions then you will get errors later on when you are calling DeviceIOControl.

In .Net you can pick various types to represent handles. I’ve seen people use Integer – which isn’t good as Integer is always 32 bits whereas handles may be 64 bits. IntPtr is a better choice as it will match the size of the C HANDLE type it is representing. HandleRef is another good choice, this is used to prevent the garbage collector from destroying your handle before a call ends – which would be embarrassing. SafeHandle is the best choice to use as it ensures that the handle will be closed in certain unusual circumstances. SafeHandle is an abstract class, there are various concrete implementations. For a device handle we can use the SafeFileHandle.

The IOCTL_CDROM_READ_TOC_EX control code can be used to get the CD-Text back from the drive. Another alternative is to use a less specific control code such as IOCTL_SCSI_PASS_THROUGH which lets you send any command to the drive, it’s a bit more involved – I’ll show how to use that later. When you are working from scratch, and trying to figure this stuff out for yourself, it helps to have a C++ project that you can use to dump out the values of the constants, size of structures, and offsets of structure fields. A bit of work in C++ can save a lot of time searching the internet with vague error messages like “A call to PInvoke function xyz has unbalanced the stack”.

If you want to set up a C++ project then the steps are:
1) Download and install the WDK. It’s a big download. The bit you need are the “Build Environments”, as selecting this will ensure that the header files are installed.
2) Start visual studio 2010 and a new C++ CLR Console application project called, say, StructSizes
3) Right click the project name in the solution explorer, click References, Add New Reference and add System.Windows.Forms.
4) Right click the project name in the solution explorer, click Properties, Drill down to Configuration Properties/VC++ Directories and then select Include Directories. Edit the string to include the path to the wdk header files. This will involve adding a “;” and then the path. Mine looks like this after the edit: $(VCInstallDir)include;$(VCInstallDir)atlmfc\include;$(WindowsSdkDir)include;$(FrameworkSDKDir)\include;C:\WinDDK\7600.16385.1\inc\api
5) As an example lets dump out the value of the IOCTL command and some info about a structure. This goes into the cpp file with the same name as the project, so StructSizes.cpp.

#include "stdafx.h"

#include <Windows.h>

#include <winioctl.h>

#include <ntddcdrm.h>

#include <ntddscsi.h>

#include <stddef.h>

using namespace System;

using namespace System::Text;

using namespace System::Windows::Forms;

[STAThread()] // to make the clipboard happy.

int main(array<System::String ^> ^args)

    StringBuilder ^sb = gcnew System::Text::StringBuilder();

    sb->AppendLine(L"IOCTL_CDROM_READ_TOC_EX: " + (IOCTL_CDROM_READ_TOC_EX).ToString(L"x2"));

    sb->AppendLine(L"SCSI_PASS_THROUGH offsets + size:");

    sb->AppendLine((offsetof(SCSI_PASS_THROUGH, SCSI_PASS_THROUGH::Length)).ToString() + L" Length");

    sb->AppendLine((offsetof(SCSI_PASS_THROUGH, SCSI_PASS_THROUGH::ScsiStatus)).ToString() + L" ScsiStatus");

    sb->AppendLine((offsetof(SCSI_PASS_THROUGH, SCSI_PASS_THROUGH::PathId)).ToString() + L" PathId");

    sb->AppendLine((offsetof(SCSI_PASS_THROUGH, SCSI_PASS_THROUGH::TargetId)).ToString() + L" TargetId");

    sb->AppendLine((offsetof(SCSI_PASS_THROUGH, SCSI_PASS_THROUGH::Lun)).ToString() + L" Lun");

    sb->AppendLine((offsetof(SCSI_PASS_THROUGH, SCSI_PASS_THROUGH::CdbLength)).ToString() + L" CdbLength");

    sb->AppendLine((offsetof(SCSI_PASS_THROUGH, SCSI_PASS_THROUGH::SenseInfoLength)).ToString() + L" SenseInfoLength");

    sb->AppendLine((offsetof(SCSI_PASS_THROUGH, SCSI_PASS_THROUGH::DataIn)).ToString() + L" DataIn");

    sb->AppendLine((offsetof(SCSI_PASS_THROUGH, SCSI_PASS_THROUGH::DataTransferLength)).ToString() + L" DataTransferLength");

    sb->AppendLine((offsetof(SCSI_PASS_THROUGH, SCSI_PASS_THROUGH::TimeOutValue)).ToString() + L" TimeOutValue");

    sb->AppendLine((offsetof(SCSI_PASS_THROUGH, SCSI_PASS_THROUGH::DataBufferOffset)).ToString() + L" DataBufferOffset");

    sb->AppendLine((offsetof(SCSI_PASS_THROUGH, SCSI_PASS_THROUGH::SenseInfoOffset)).ToString() + L" SenseInfoOffset");

    sb->AppendLine((offsetof(SCSI_PASS_THROUGH, SCSI_PASS_THROUGH::Cdb[0])).ToString() + L" Cdb[0]");

    sb->AppendLine(L"**TOTAL SIZE: " + (sizeof(SCSI_PASS_THROUGH)).ToString());

    sb->AppendLine();

    sb->AppendLine();

    Console::WriteLine(sb->ToString());

    Clipboard::SetText(sb->ToString());

    Console::ReadKey();

    return 0;

6) It should build and run. It sets the clipboard with the text. You can’t dump out the offset of bit fields, like you get in the CDROM_READ_TOC_EX structure. You should dump out x86 and x64 versions so that you can check your .Net structures match on both.

Let’s say you’ve made your .Net structure, called ScsiPassThrough, and want to see the offset of the Length field and the size. You would use the SizeOf and OffsetOf methods of the Marshal class which is in the System.Runtime.InteropServices namespace. e.g.:

Console.WriteLine(Marshal.OffsetOf(GetType(ScsiPassThrough), "Length").ToString)

Console.WriteLine(Marshal.SizeOf(GetType(ScsiPassThrough)))

Ok, back to the task in hand. We want to send IOCTL_CDROM_READ_TOC_EX which has the value &H24054. The documentation says we have to send a structure CDROM_READ_TOC_EX to specify what exactly we want to get back from the TOC.

typedef struct _CDROM_READ_TOC_EX {

    UCHAR Format    : 4;

    UCHAR Reserved1 : 3; // future expansion

    UCHAR Msf       : 1;

    UCHAR SessionTrack;

    UCHAR Reserved2;     // future expansion

    UCHAR Reserved3;     // future expansion

} CDROM_READ_TOC_EX, *PCDROM_READ_TOC_EX;

This structure has a size of 4 bytes on x86 and x64. We need to set the Format field to CDROM_READ_TOC_EX_FORMAT_CDTEXT (value 5) to say we want to retrieve CD Text. All the others will be 0. The structure is made up of 4 bytes. SessionTrack, Reserved2 and Reserved3 get a byte each. The other byte is divided up into 3 fields – Format, Reserved1 and Msf. Format takes the lo 4 bits of the byte. Reserved takes the next 3 and Msf takes the hi bit. We can’t split fields up in .Net like that. We can either declare a structure that has 4 byte fields, and expose the three bit fields with properties, or, as we just want to set the one field, we could also just send an integer with the correct bit pattern - an integer has the same size and all the dll that we are calling cares about is that it gets 4 bytes with the correct bits set. I came up with this:

<StructLayout(LayoutKind.Sequential)>

Friend Structure CDROM_READ_TOC_EX

    Public FormatReservedMsf As Byte

    Public SessionTrack As Byte

    Public Reserved2 As Byte

    Public Reserved3 As Byte

    ' properties will just read the public fields without contributing to the size of the structure.

    Public ReadOnly Property Format As ReadTocExFormat

Get

            Return CType(FormatReservedMsf And &HF, ReadTocExFormat)

        End Get

    End Property

    Public ReadOnly Property Reserved1 As Integer

Get

            Return (FormatReservedMsf >> 4) And &H7

        End Get

    End Property

    Public ReadOnly Property Msf As Boolean

Get

            Return (FormatReservedMsf And &H80) = &H80

        End Get

    End Property

    Public Sub SetFormatReservedMsf(format As ReadTocExFormat, msf As Boolean)

        FormatReservedMsf = CByte(format Or If(msf, &H80, 0))

    End Sub

    Public ReadOnly Property Size As Integer

Get

            Return 4

        End Get

    End Property

End Structure

The documentation says that when we send the message we should also send a buffer. On return the buffer will contain a CDROM_TOC_CD_TEXT_DATA structure, followed by an array of CDROM_TOC_CD_TEXT_DATA_BLOCK structures. So – how big should the buffer be to hold all this? The answer is that we don’t know. We can either create a huge buffer that will be big enough, or we can call once to read the CDROM_TOC_CD_TEXT_DATA.Length field and use that to size the buffer. The buffer can be an array of bytes – they are easy to marshal if one of the parameters states the size of the array. DeviceIOControl will look like this:

<DllImport("kernel32", SetLastError:=True)>

Public Shared Function DeviceIoControl(hVol As SafeFileHandle, controlCode As Integer,

   ByRef inbuffer As CDROM_READ_TOC_EX, inBufferSize As Integer,

   <MarshalAs(UnmanagedType.LPArray, SizeParamIndex:=6)> ByVal outBuffer() As Byte,

   outBufferSize As Integer,

   <Out()> ByRef bytesReturned As Integer, ovelapped As IntPtr) As Boolean

End Function

Note the structure goes ByRef – it’s a value type and we don’t want to send the whole structure to the function as it is expecting a pointer to the structure. Passing it ByRef tells the marshaller to send a pointer. The array, being a reference type, goes ByValue.

So the first time we call it we want to just get the Length field which is a WORD field, 2 bytes. Then we can call it again with a byte array that is this Length field + 2 as the value of the Length field is the size not including itself. The bytes are the wrong way round to read as a UShort with the BitConverter. I guess you could reverse the array. At this point my program gets the bytes and doesn’t do anything with them…

Imports System.IO

Imports System.Runtime.InteropServices

Public Class CdTextRetriever

    Private Const IOCTL_CDROM_READ_TOC_EX As UInteger = &H24054

    Public Shared Function GetCdText(driveInfo As DriveInfo) As Object

        Dim cdText As Object = Nothing ' don't know what the return will look like yet.

        Dim devicePath As String = String.Format("\\.\{0}:", driveInfo.Name(0))

        Const FILE_ATTRIBUTE_NORMAL As UInteger = &H80

        Const GENERIC_READ As UInteger = &H80000000UI

        Const GENERIC_WRITE As UInteger = &H40000000

        Const FILE_SHARE_READ As UInteger = 1

        Const FILE_SHARE_WRITE As UInteger = 2

        Const OPEN_EXISTING As UInteger = 3

        Using hDevice As SafeFileHandle = NativeMethods.CreateFile(devicePath,

                GENERIC_READ Or GENERIC_WRITE,

                FILE_SHARE_READ Or FILE_SHARE_WRITE,

                IntPtr.Zero, OPEN_EXISTING,

                FILE_ATTRIBUTE_NORMAL, IntPtr.Zero)

            If hDevice.IsInvalid OrElse hDevice.IsClosed Then Throw New Win32Exception

            ReadCdText(hDevice)

        End Using

        Return cdText

    End Function

    Private Shared Sub ReadCdText(hDevice As SafeFileHandle)

        Dim size As Integer = GetCdTextSize(hDevice)

        Dim bytes(size - 1) As Byte

        ReadCdText(hDevice, bytes)

        Debugger.Break()

        ' TODO: Decode the bytes!

    End Sub

    Private Shared Function GetCdTextSize(hDevice As SafeFileHandle) As Integer

        Dim bytes(1) As Byte ' 2 bytes to read the size of the buffer required

        ReadCdText(hDevice, bytes)

        Return (CType(bytes(0), Integer) << 8) Or bytes(1) + 2

    End Function

    Private Shared Sub ReadCdText(hDevice As SafeFileHandle, bytes() As Byte)

        Dim request As New CDROM_READ_TOC_EX

        request.SetFormatReservedMsf(ReadTocExFormat.CDROM_READ_TOC_EX_FORMAT_CDTEXT, False)

        Dim returned As Integer = 0

        Dim result As Boolean = DeviceIoControl(hDevice, IOCTL_CDROM_READ_TOC_EX, request,

                                                 request.Size, bytes, bytes.Length,

                                                 returned, IntPtr.Zero)

        If result = False Then Throw New Win32Exception

    End Sub

End Class

Sending the SCSI INQUIRY command with DeviceIOControl

2011-02-12T12:25:00.001Z

Option Strict On
Option Explicit On

Imports System.Runtime.InteropServices
Imports Microsoft.Win32.SafeHandles
Imports System.Security
Imports System.ComponentModel
Imports System.Text

Module Module1

    <SuppressUnmanagedCodeSecurity()> _
    Private Class NativeMethods
        <DllImport("kernel32", SetLastError:=True)> _
        Public Shared Function CreateFile( _
         ByVal FileName As String, _
         ByVal DesiredAccess As Integer, _
         ByVal ShareMode As Integer, _
         ByVal SecurityAttributes As IntPtr, _
         ByVal CreationDisposition As Integer, _
         ByVal FlagsAndAttributes As Integer, _
         ByVal hTemplateFile As IntPtr) As SafeFileHandle
        End Function

        <DllImport("kernel32.dll", SetLastError:=True)> _
        Friend Shared Function DeviceIoControl( _
            ByVal deviceHandle As SafeFileHandle, _
            ByVal controlCode As Integer, _
            ByRef inBuffer As ScsiPassThroughWithBuffers, _
            ByVal inBufferSize As Integer, _
            ByRef outBuffer As ScsiPassThroughWithBuffers, _
            ByVal outBufferSize As Integer, _
            ByRef bytesReturned As Integer, _
            ByVal overlapped1 As IntPtr) As Boolean
        End Function
    End Class

    <StructLayout(LayoutKind.Sequential, pack:=8)> _
    Private Structure ScsiPassThrough
        Public Length As Short
        Public ScsiStatus As Byte
        Public PathId As Byte          ' port / bus
        Public TargetId As Byte        ' controller
        Public Lun As Byte             ' Lun
        Public CdbLength As Byte
        Public SenseInfoLength As Byte
        Public DataIn As Byte
        Public DataTransferLength As Integer
        Public TimeOutValue As Integer
        Public DataBufferOffset As IntPtr
        Public SenseInfoOffset As Integer
        <MarshalAs(UnmanagedType.ByValArray, SizeConst:=16)> _
        Public Cdb() As Byte
        Public Sub Init()
            Me.Length = CShort(Marshal.SizeOf(GetType(ScsiPassThrough)))
            CdbLength = 6                   ' Size of our command structure
            SenseInfoLength = 32            ' Size of our buffer that may be filled with error/status info
            DataIn = 1                      ' SCSI_IOCTL_DATA_IN 
            DataTransferLength = 128        ' Size of our buffer that gets filled with informaion
            TimeOutValue = 10
            ' TargetId, PathId and Lun are filled on return. Don't mean anything on the way out.
            DataBufferOffset = Marshal.OffsetOf(GetType(ScsiPassThroughWithBuffers), "Data")
            SenseInfoOffset = Marshal.OffsetOf(GetType(ScsiPassThroughWithBuffers), "Sense").ToInt32
            Cdb = New Byte(15) {}
            Cdb(0) = &H12
            Cdb(4) = 128
        End Sub
    End Structure

    <StructLayout(LayoutKind.Sequential, pack:=8)> _
    Private Structure ScsiPassThroughWithBuffers
        Public Spt As ScsiPassThrough
        <MarshalAs(UnmanagedType.ByValArray, SizeConst:=32)> _
        Public Sense() As Byte
        <MarshalAs(UnmanagedType.ByValArray, SizeConst:=128)> _
        Public Data() As Byte
        Public Sub Init()
            Sense = New Byte(31) {}
            Data = New Byte(127) {}
            Spt = New ScsiPassThrough
            Spt.Init()
        End Sub
    End Structure

    Private Enum PeripheralDeviceType
        Sbc2 = 0 ' direct access block device (disk)
        Ssc2 = 1 ' sequential access block device (tape)
        Ssc = 2  ' Printer
        Spc2 = 3 ' Processor
        Sbc = 4  ' Write once
        Mmc = 5  ' CD/DVD etc
        SbcOptical = 7 ' Optical memory device
        Smc2 = 8 ' Medium changer
        scc2 = &HC ' storage array controller (raid)
        Ses = &HD  ' enclosure services device
        Rbc = &HE  ' simple direct access device
        Ocrw = &HF ' optical card reader
        Bcc = &H10 ' bridge controller 
        Osd = &H11 ' object based storage device
        Adc = &H12 ' automation / drive interface
        WellKnown = &H1E
        Unknown = &H1F
    End Enum

    Sub Main()
        Console.WriteLine("Enter a drive letter")
        Dim letter As Char = Console.ReadKey.KeyChar
        Console.WriteLine()
        Const GenericRead As Integer = &H80000000
        Const GenericWrite As Integer = &H40000000
        Const FileShareRead As Integer = 1
        Const FileShareWrite As Integer = 2
        Const OpenExisting As Integer = 3
        Dim drivePath As String = String.Concat("\\.\" & letter & ":")
        Console.WriteLine("Trying path: " & drivePath)
        Using driveHandle As SafeFileHandle = NativeMethods.CreateFile( _
         drivePath, _
         GenericRead Or GenericWrite, _
         FileShareRead Or FileShareWrite, _
         IntPtr.Zero, _
         OpenExisting, _
         0, _
         IntPtr.Zero)
            If driveHandle.IsInvalid Then
                Console.WriteLine("CreateFile ERROR: " & (New Win32Exception).Message)
                Console.ReadKey()
                Return
            End If
            Dim sptwb As New ScsiPassThroughWithBuffers
            sptwb.Init()

            Dim inBufferSize As Integer = Marshal.SizeOf(GetType(ScsiPassThroughWithBuffers))
            Dim bytesReturned As Integer
            Const IOCTL_SCSI_PASS_THROUGH As Integer = &H4D004
            Dim result As Boolean = NativeMethods.DeviceIoControl(driveHandle, IOCTL_SCSI_PASS_THROUGH, _
                sptwb, inBufferSize, sptwb, inBufferSize, bytesReturned, IntPtr.Zero)
            If result = False Then
                Console.WriteLine("DeviceIOControl ERROR: {0} {1}", Marshal.GetLastWin32Error.ToString("x"), (New Win32Exception).Message)
                Console.ReadKey()
                Return
            End If
            Dim bytes() As Byte = sptwb.Data
            Dim peripheralQualifier As Integer = bytes(0) >> 5
            If peripheralQualifier = 1 Then Console.WriteLine("No peripheral is attached to the device")
            Dim peripheralDevice As PeripheralDeviceType = CType(bytes(0) And &H1F, PeripheralDeviceType)
            Console.WriteLine("Peripheral device type: " & peripheralDevice.ToString)
            Console.WriteLine("Version of the standard:" & sptwb.Data(2))
            Console.WriteLine("Additional Length: " & sptwb.Data(4))
            DumpString("Vendor Id: ", sptwb.Data, 8, 8)
            DumpString("Product Id: ", sptwb.Data, 16, 16)
            DumpString("Product Revision Level: ", sptwb.Data, 32, 4)
            DumpString("Serial no: ", sptwb.Data, 36, 8)
            Console.WriteLine("Press any key")
            Console.ReadKey()
        End Using
    End Sub

    Private Sub DumpString(msg As String, bytes() As Byte, offset As Integer, length As Integer)
        Console.WriteLine(String.Format("{0} :'{1}'", msg, ASCIIEncoding.ASCII.GetString(bytes, offset, length)))
    End Sub

End Module

The serial number is unreliable. The peripheral device type tells you which standard the device is using. I’m trying to work out how to get the serial no of my raided or USB drives. This command is getting back the serial number of my controller card for my raid array when I ask it for \\.\C:

Enter a drive letter
c
Trying path: \\.\c:
Peripheral device type: Sbc2
Version of the standard:4
Additional Length: 43
Vendor Id: :'AMD '
Product Id: :'2+0 Stripe/RAID0'
Product Revision Level: :'1.10'
Serial no: :'98031612'
Press any key

Getting Hard disk drive info with DeviceIOControl

2011-02-12T01:06:00.002Z

It’s a pretty popular question on forums – how do I get the serial number for a hard disk drive. The serial number is then used for some form of homebrew security. The consensus amongst those who’ve been programming a while is that it is a waste of time and effort, unreliable and not particularly good at securing your programs…

Anyway, as a fun challenge I had a go at getting the serial number from my laptops ATA-attached drive, by using DeviceIOControl to send the IDENTIFY DEVICE ATA command, as defined in the ATA spec. This won’t work on SCSI drives, or raid or …,… ,…, so it’s not reliable and isn’t the answer for those of you looking for a unique id (there isn’t a reliable unique id).

Imports System.Runtime.InteropServices

Imports Microsoft.Win32.SafeHandles

Imports System.Security

Imports System.ComponentModel

Imports System.Text

Module Module1

    <SuppressUnmanagedCodeSecurity()> _

    Private Class NativeMethods

        <DllImport("kernel32", SetLastError:=True)> _

        Public Shared Function CreateFile( _

         ByVal FileName As String, _

         ByVal DesiredAccess As Integer, _

         ByVal ShareMode As Integer, _

         ByVal SecurityAttributes As IntPtr, _

         ByVal CreationDisposition As Integer, _

         ByVal FlagsAndAttributes As Integer, _

         ByVal hTemplateFile As IntPtr) As SafeFileHandle

        End Function

        <DllImport("kernel32.dll", SetLastError:=True)> _

        Friend Shared Function DeviceIoControl( _

            ByVal deviceHandle As SafeFileHandle, _

            ByVal controlCode As Integer, _

            ByRef inBuffer As ATA_PASS_THROUGH_EX_WITH_BUFFERS, _

            ByVal inBufferSize As Integer, _

            ByRef outBuffer As ATA_PASS_THROUGH_EX_WITH_BUFFERS, _

            ByVal outBufferSize As Integer, _

            ByRef bytesReturned As Integer, _

            ByVal overlapped1 As IntPtr) As Boolean

        End Function

    End Class

    <StructLayout(LayoutKind.Sequential)> _

    Private Structure ATA_PASS_THROUGH_EX

        Public Length As Short

        Public AtaFlags As Short

        Public PathId As Byte

        Public TargetId As Byte

        Public Lun As Byte

        Public ReservedAsUchar As Byte

        Public DataTransferLength As Integer

        Public TimeOutValue As Integer

        Public ReservedAsUlong As Integer

        Public DataBufferOffset As IntPtr

        <MarshalAs(UnmanagedType.ByValArray, sizeconst:=8)> _

        Public PreviousTaskFile() As Byte

        <MarshalAs(UnmanagedType.ByValArray, sizeconst:=8)> _

        Public CurrentTaskFile() As Byte

    End Structure

    <StructLayout(LayoutKind.Sequential)> _

    Private Structure ATA_PASS_THROUGH_EX_WITH_BUFFERS

        Public Apt As ATA_PASS_THROUGH_EX

        <MarshalAs(UnmanagedType.ByValArray, sizeconst:=512)> _

        Public Data() As Byte

    End Structure

    Sub Main()

        Console.WriteLine("Enter a drive letter")

        Dim letter As Char = Console.ReadKey.KeyChar

        Console.WriteLine()

        Const GenericRead As Integer = &H80000000

        Const GenericWrite As Integer = &H40000000

        Const FileShareRead As Integer = 1

        Const FileShareWrite As Integer = 2

        Const OpenExisting As Integer = 3

        Dim drivePath As String = String.Concat("\\.\" & letter & ":")

        Console.WriteLine("Trying path: " & drivePath)

        Using driveHandle As SafeFileHandle = NativeMethods.CreateFile( _

         drivePath, _

         GenericRead Or GenericWrite, _

         FileShareRead Or FileShareWrite, _

         IntPtr.Zero, _

         OpenExisting, _

         0, _

         IntPtr.Zero)

            If driveHandle.IsInvalid Then

                Console.WriteLine("CreateFile ERROR: " & (New Win32Exception).Message)

                Console.ReadKey()

                Return

            End If

            Dim apex As New ATA_PASS_THROUGH_EX

            apex.Length = Marshal.SizeOf(apex)

            apex.AtaFlags = 2 ' ATA_FLAGS_DATA_IN

            apex.DataTransferLength = 512 ' The command returns a 512 byte package of info.

            apex.TimeOutValue = 10 ' 10 second timeout.

            apex.DataBufferOffset = Marshal.OffsetOf(GetType(ATA_PASS_THROUGH_EX_WITH_BUFFERS), "Data")

            apex.CurrentTaskFile = New Byte(7) {} ' This contains the command we are requesting.

            apex.CurrentTaskFile(6) = &HEC        ' <-- the command "IDENTIFY DEVICE"

            Dim apexb As New ATA_PASS_THROUGH_EX_WITH_BUFFERS

            apexb.Apt = apex

            Dim inBufferSize As Integer = Marshal.SizeOf(GetType(ATA_PASS_THROUGH_EX_WITH_BUFFERS))

            Dim bytesReturned As Integer

            Const IOCTL_ATA_PASS_THROUGH As Integer = &H4D02C

            Dim result As Boolean = NativeMethods.DeviceIoControl(driveHandle, IOCTL_ATA_PASS_THROUGH, _

                apexb, inBufferSize, apexb, inBufferSize, bytesReturned, IntPtr.Zero)

            If result = False Then

                Console.WriteLine("DeviceIOControl ERROR: " & (New Win32Exception).Message)

                Console.ReadKey()

                Return

            End If

            DumpString("S/N: ", apexb.Data, 20, 20)

            DumpString("Firmware: ", apexb.Data, 46, 8)

            DumpString("Model: ", apexb.Data, 54, 40)

            Console.WriteLine("Press any key")

            Console.ReadKey()

        End Using

    End Sub

    Private Sub DumpString(msg As String, bytes() As Byte, offset As Integer, length As Integer)

        ' The strings are slightly weird - endianness? If you use ASCII.GetBytes then each character

        ' pair is reversed.

        Dim sb As New StringBuilder(msg & " '")

        For i As Integer = offset To offset + length - 1 Step 2

            sb.Append(Chr(bytes(i + 1)))

            sb.Append(Chr(bytes(i)))

        Next

        sb.Append("'"c)

        Console.WriteLine(sb.ToString)

    End Sub

End Module

Output on my laptop:

Enter a drive letter
c
Trying path: \\.\c:
S/N: '            5TG077W9'
Firmware: 'DE14    '
Model: 'ST9160411ASG                            '
Press any key

HDS_FILTERBAR

2010-06-15T01:06:00.001+01:00

There’s a ListViewFilter control in C# on codeproject from 2003. It displays a filter bar in the column headers by setting HDS_FILTERBAR.

If we start off with a ListView showing some random data in a few columns:

And set the HDS_FILTERBAR style, then it will display the filter bar:

But there’s a problem – it hasn’t resized the header controls – they need to be taller to fit the text in properly. The codeproject code makes the column resize using a hack. Here’s how it shows the filter bar:

// set/reset the flag for the filterbar
if ( hdr_filter ) style |= HDS_FILTR;
else style ^= HDS_FILTR;
SetWindowLong( Handle, W32_GWL.GWL_STYLE, style );

And here’s the self-confessed kludge that gets it to resize:

// now we have to resize this control.  we do this by sending
// a set item message to column 0 to change it's size.  this
// is a kludge but the invalidate and others just don't work.
hdr_hditem.mask = W32_HDI.HDI_HEIGHT;
SendMessage( Handle, W32_HDM.HDM_GETITEMW, 0, ref hdr_hditem );
hdr_hditem.cxy += ( hdr_filter ) ? 1 : -1;
SendMessage( Handle, W32_HDM.HDM_SETITEMW, 0, ref hdr_hditem );

It’s sending a message to alter a property of the header – using HDI_HEIGHT. If we look at the windows header files to see how it’s defined:

#define HDI_WIDTH               0x0001
#define HDI_HEIGHT              HDI_WIDTH

It’s actually the same as the width. The kludge increases the width of the column header by 1 when the filter is shown, and decreases it when the filter is not shown. Altering the width must be enough to make windows resize the control.

Searching for alternate solutions I found one that mentions using MoveWindow to resize the header control, so I tried that. Unfortunately when you resize the header it then overlaps the parent listview, hiding one or two of the ListViewItems by overlapping them.

The info needed to do it properly is in the “Header Controls” topic in the MSDN library, in the “header control size and position” paragraph. We have to send the HDM_LAYOUT message to the control, specifying the bounds of the parent. On return we get a WINDOWPOS structure which tells us the best bounds for the header so that it will sit in the bounds of the parent. All we then have to do is to resize the header control using SetWindowPos, and alter the bounds of the parent control so that its top lies below the header and its height isn’t too big.

HDLAYOUT layout = new HDLAYOUT();
RECT rect = new RECT();
rect.Right = parent.ClientSize.Width;
rect.Bottom = parent.ClientSize.Height;
layout.prc = Marshal.AllocHGlobal(Marshal.SizeOf(rect));
Marshal.StructureToPtr(rect, layout.prc, true);
layout.pwpos = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(WINDOWPOS)));
lresult = NativeMethods.SendMessage(Handle, HDM_LAYOUT, IntPtr.Zero, ref layout);
Marshal.FreeHGlobal(layout.prc);
WINDOWPOS pos = (WINDOWPOS)Marshal.PtrToStructure(layout.pwpos, typeof(WINDOWPOS));
Marshal.FreeHGlobal(layout.pwpos);
bool res = NativeMethods.SetWindowPos(Handle, IntPtr.Zero, pos.X, pos.Y, pos.Width, pos.Height, 
    SetWindowPosFlags.NoMove | SetWindowPosFlags.NoZOrder | SetWindowPosFlags.FrameChanged);
res = NativeMethods.SetWindowPos(parent.Handle, IntPtr.Zero, 0, pos.Height, parent.Width, parent.Height - pos.Height, 
    SetWindowPosFlags.NoMove | SetWindowPosFlags.NoZOrder | SetWindowPosFlags.FrameChanged);
ClearAllFilters();

Now the filterbar is shown with the correct size, it doesn’t overlap the top of the parent listview, and it resizes correctly when the filter bar is removed.

Cloudy Jelly

2009-10-09T23:49:00.001+01:00

The usual advice is to stick the boiled up fruit in a bag and leave to drip. Don’t squeeze the bag, or it will be cloudy. Well, my investigations have found that it’s not really the lack of bag squeezing the helps to get clear jelly. It’s the leaving it overnight. You then take the liquor off any sediment that’s fallen to the bottom of the bucket.

I just did my annual crab apple jelly. 8lbs of crab apples. For one batch I let it drip into a bucket, didn’t squeeze and made the jam immediately. The result was pretty cloudy. For the other, I squeezed that first bag and strained through a bit more, which also got a really good squeeze. I then left it in the fridge for a day, because I was tired of making jelly. The bits all settled to the bottom, and the result is perfectly clear. So – you can squeeze the bag, so long as you leave it to settle.

Oh, and crab apple and haw jelly isn’t great. The haws smell like sardines whilst cooking, and make a very sharp jelly. Maybe I stuck too many in. Still, it’s not ruined, just not really worth the bother when the straight stuff tastes so good.

There, a dumb entry to get this thing going again. I’ve been busy, and not programmed much.

Shuffle things in .Net

2009-02-12T06:44:00.003Z

Shuffling is complicated. There are two nice pages on CodingHorror:

http://www.codinghorror.com/blog/archives/001008.html

http://www.codinghorror.com/blog/archives/001015.html

The second link shows a chart of the counts of the different possible draws from a card pack when you do it a few hundred thousand times. This detects the bias of an algorithm.

How not to shuffle # 1

Here we go for the approach of picking a number at random, seeing if we have selected it already, adding it to the selected numbers if we haven't, and picking another if we have.

Public Class Form1

    Private Shared rand As New Random
    Private dic As New Dictionary(Of Integer, Integer)
    Dim tb As New TextBox With {.Dock = DockStyle.Fill, .Multiline = True}

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim sw As Stopwatch = Stopwatch.StartNew
        Dim shuffled(9999999)() As Integer
        For i As Integer = 0 To shuffled.GetUpperBound(0)
            shuffled(i) = GetShuffledDeck(4)
        Next
        sw.Stop()
        For i As Integer = 0 To shuffled.GetUpperBound(0)
            Dim key As Integer = shuffled(i)(0) + shuffled(i)(1) * 10 + shuffled(i)(2) * 100 + shuffled(i)(3) * 1000
            If dic.ContainsKey(key) Then
                dic(key) = dic(key) + 1
            Else
                dic.Add(key, 1)
            End If
        Next
        Dim sb As New System.Text.StringBuilder
        sb.AppendLine(sw.ElapsedMilliseconds.ToString & "ms.")
        For Each kvp As KeyValuePair(Of Integer, Integer) In dic
            sb.Append(kvp.ToString & " ")
        Next
        tb.Text = sb.ToString
        Me.Controls.Add(tb)
    End Sub

    Function GetShuffledDeck(ByVal numCards As Integer) As Integer()
        Dim cards(numCards - 1) As Integer
        For index As Integer = 0 To cards.Length - 1 ' BTW (cards.Length - 1) will be optimized.
            Dim card As Integer
            Do
                ' We don't want two identical cards.
                card = rand.Next(1, numCards + 1)
            Loop While cards.Contains(card)
            cards(index) = card
        Next
        Return cards
    End Function

End Class

This is slow, (O(n^2). My results:

29400ms.
[4312, 416350] [3241, 417266] [4231, 417358] [3214, 416887]
[2134, 416303] [3421, 416548] [4321, 415916] [1324, 415585]
[1234, 417627] [3412, 416762] [4132, 415979] [1432, 416423]
[2143, 416603] [3142, 416542] [1423, 417515] [2314, 416934]
[2341, 417028] [1243, 416388] [2431, 415852] [1342, 417022]
[2413, 416309] [4213, 418019] [3124, 417387] [4123, 415397]

They don't look biased. Standard deviation from the mean is 653.
Certainly not as much as those on the codinghorror site. Let's redo that one...

How not to shuffle # 2

Using the same code with a different shuffle function:

Function GetShuffledDeck(ByVal numCards As Integer) As Integer()
    Dim cards(numCards - 1) As Integer
    For i As Integer = 0 To cards.Length - 1
        cards(i) = i + 1
    Next
    For i As Integer = 0 To cards.Length - 1
        Dim n As Integer = rand.Next(cards.Length)
        Dim temp As Integer = cards(i)
        cards(i) = cards(n)
        cards(n) = temp
    Next
    Return cards
End Function

3618ms.
[1234, 390450] [1243, 390582] [1324, 312355] [1342, 429289]
[1423, 429646] [1432, 547601] [2134, 390203] [2143, 429178]
[2314, 351753] [2341, 351524] [2413, 429756] [2431, 545840]
[3124, 350694] [3142, 430600] [3214, 312704] [3241, 430164]
[3412, 586053] [3421, 391312] [4123, 351567] [4132, 546387]
[4213, 429804] [4231, 391291] [4312, 390192] [4321, 391055]

There's bias there. s.d. = 71880!!!

How to shuffle # 1 - Knuth shuffle / Fisher-Yates

Here I initialize the Random object with a cryptographically strong seed. Bit better than the default? The default uses the Environment.TickCount, which could be used to work out likely starting seed values.... Not likely to actually happen....
The main difference is the algorithm though, which no longer introduces bias.

Imports System.Security.Cryptography

Public Class Form1

    Private Shared rand As Random
    Private dic As New Dictionary(Of Integer, Integer)
    Dim tb As New TextBox With {.Dock = DockStyle.Fill, .Multiline = True}

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        ' get a random seed rather than using the default Random constructor, which
        ' just uses the Environment.TickCount
        Dim rng As New RNGCryptoServiceProvider
        Dim seedBytes(3) As Byte
        rng.GetBytes(seedBytes)
        rand = New Random(BitConverter.ToInt32(seedBytes, 0))
        Dim sw As Stopwatch = Stopwatch.StartNew
        Dim shuffled(9999999)() As Integer
        For i As Integer = 0 To shuffled.GetUpperBound(0)
            shuffled(i) = GetShuffledDeck(4)
        Next
        sw.Stop()
        For i As Integer = 0 To shuffled.GetUpperBound(0)
            Dim key As Integer = shuffled(i)(0) + shuffled(i)(1) * 10 + shuffled(i)(2) * 100 + shuffled(i)(3) * 1000
            If dic.ContainsKey(key) Then
                dic(key) = dic(key) + 1
            Else
                dic.Add(key, 1)
            End If
        Next
        Dim sb As New System.Text.StringBuilder
        sb.AppendLine(sw.ElapsedMilliseconds.ToString & "ms.")
        Dim keys As New List(Of Integer)(dic.Keys)
        keys.Sort()
        For Each key As Integer In keys
            sb.AppendFormat("[{0}, {1}] ", key, dic(key))
        Next
        tb.Text = sb.ToString
        Me.Controls.Add(tb)
    End Sub

    Function GetShuffledDeck(ByVal numCards As Integer) As Integer()
        Dim cards(numCards - 1) As Integer
        For i As Integer = 0 To cards.Length - 1
            cards(i) = i + 1
        Next
        For i As Integer = cards.Length - 1 To 0 Step -1
            Dim n As Integer = rand.Next(i + 1)
            Dim temp As Integer = cards(i)
            cards(i) = cards(n)
            cards(n) = temp
        Next
        Return cards
    End Function

End Class

3564ms.
[1234, 417700] [1243, 416060] [1324, 416157] [1342, 416886]
[1423, 416348] [1432, 416439] [2134, 416352] [2143, 417366]
[2314, 416459] [2341, 417555] [2413, 417086] [2431, 416996]
[3124, 415841] [3142, 417191] [3214, 416693] [3241, 416009]
[3412, 416599] [3421, 416026] [4123, 416222] [4132, 416616]
[4213, 416332] [4231, 417548] [4312, 417035] [4321, 416484]

Bias free. s.d. = 526

How to shuffle # 2 - Sorting with a GUID

Again we can just alter the function:

Function GetShuffledDeck(ByVal numCards As Integer) As Integer()
    Dim cards = Enumerable.Range(1, numCards)
    cards = cards.OrderBy(Function(x) Guid.NewGuid)
    Return cards.ToArray
End Function

20129ms.
[1234, 417906] [1243, 416614] [1324, 416582] [1342, 416302]
[1423, 416529] [1432, 416558] [2134, 416695] [2143, 416061]
[2314, 417049] [2341, 415870] [2413, 416690] [2431, 417183]
[3124, 415954] [3142, 416735] [3214, 415955] [3241, 415697]
[3412, 417235] [3421, 416427] [4123, 417626] [4132, 417726]
[4213, 417010] [4231, 415691] [4312, 418397] [4321, 415508]

Slow again. s.d. = 733

How to shuffle # 2 - Sorting with a load of random Doubles

Option Infer On

Imports System.Security.Cryptography

Public Class Form1

    Private Shared rand As Random
    Private dic As New Dictionary(Of Integer, Integer)
    Private tb As New TextBox With {.Dock = DockStyle.Fill, .Multiline = True}
    Private rng As New RNGCryptoServiceProvider

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim sw As Stopwatch = Stopwatch.StartNew
        Dim shuffled(9999999)() As Integer
        For i As Integer = 0 To shuffled.GetUpperBound(0)
            shuffled(i) = GetShuffledDeck(4)
        Next
        sw.Stop()
        For i As Integer = 0 To shuffled.GetUpperBound(0)
            Dim key As Integer = shuffled(i)(0) + shuffled(i)(1) * 10 + shuffled(i)(2) * 100 + shuffled(i)(3) * 1000
            If dic.ContainsKey(key) Then
                dic(key) = dic(key) + 1
            Else
                dic.Add(key, 1)
            End If
        Next
        Dim sb As New System.Text.StringBuilder
        sb.AppendLine(sw.ElapsedMilliseconds.ToString & "ms.")
        Dim keys As New List(Of Integer)(dic.Keys)
        keys.Sort()
        For Each key As Integer In keys
            sb.AppendFormat("[{0}, {1}] ", key, dic(key))
        Next
        tb.Text = sb.ToString
        Me.Controls.Add(tb)
    End Sub

    Function GetShuffledDeck(ByVal numCards As Integer) As Integer()
        Dim cards = Enumerable.Range(1, numCards)
        cards = cards.OrderBy(Function(x) RandomDouble(x))
        Return cards.ToArray
    End Function

    ' This returns a function that creates a random double. The Integer bit is just ignored. 
    Private Function RandomDouble() As Func(Of Integer, Double)
        ' 8 bytes for the double. 
        Dim bytes(7) As Byte
        ' Get cryptographically strong random bytes into the array.       
        rng.GetBytes(bytes)
        ' The function uses the bytes to create a double. x is ignored. 
        Dim getDouble = Function(x As Integer) BitConverter.ToDouble(bytes, 0)
        Return getDouble
    End Function

End Class

137380ms.
[1234, 416945] [1243, 416314] [1324, 416742]
[1342, 416652] [1423, 417382] [1432, 416208]
[2134, 417577] [2143, 416464] [2314, 415925]
[2341, 416543] [2413, 416615] [2431, 418076]
[3124, 416493] [3142, 415963] [3214, 417219]
[3241, 415923] [3412, 416774] [3421, 417394]
[4123, 416466] [4132, 416706] [4213, 415900]
[4231, 416736] [4312, 415534] [4321, 417449]

Slooooooooooooooooooooooooooooooow. - The cryptographic random numbers are very expensive!

s.d. = 605

So there you go. But, it's interesting to note atma's comments about experienced card players - they don't like their cards shuffled by the computer, they prefer human shuffled cards and can tell the difference.

Rotated Rectangle Collision – VB.Net

2009-02-09T23:23:00.003Z

I translated some C code by Oren Becker that determines if two rotated RectangleFs are overlapping. The rectangles are defined by their centre, size and angle of rotation. In the original code the size was actually (Width / 2, Height / 2) which was confusing.

RotatedRectangleF.vb

Public Structure RotatedRectangleF

    Public Const Pi As Single = CType(Math.PI, Single)

    Private m_centre As PointF
    ''' <summary>
    ''' Gets or sets the coordinates of the centre of this RotatedRectangleF structure.
    ''' </summary>    
    ''' <returns>
    ''' A System.Drawing.PointF that represents the centre of this RotatedRectangleF structure.
    ''' </returns>
    Public Property Centre() As PointF
        Get
            Return m_centre
        End Get
        Set(ByVal value As PointF)
            m_centre = value
        End Set
    End Property

    Private m_size As SizeF
    ''' <summary>
    ''' Gets or sets the size of this RotatedRectangleF.
    ''' </summary>    
    ''' <returns>
    ''' A System.Drawing.SizeF that represents the width and height of this RotatedRectangleF structure.
    ''' </returns>
    Public Property Size() As SizeF
        Get
            Return m_size
        End Get
        Set(ByVal value As SizeF)
            m_size = value
        End Set
    End Property

    Private m_angle As Single
    ''' <summary>
    ''' Gets or sets the angle in degrees measured clockwise from the x-axis that this RotatedRectangleF structure is rotated.
    ''' </summary>
    ''' <returns>
    ''' A Single representing the angle in degrees measured clockwise from the x-axis that this RotatedRectangleF structure is rotated.
    ''' </returns>
    Public Property Angle() As Single
        Get
            Return m_angle
        End Get
        Set(ByVal value As Single)
            m_angle = value
        End Set
    End Property

    ''' <summary>
    ''' Initializes a new instance of the RotatedRectangleF stucture with the specified centre, size and angle.
    ''' </summary>
    ''' <param name="centre">The centre of the RotatedRectangleF instance.</param>
    ''' <param name="size">The size of the RotatedRectangleF instance.</param>
    ''' <param name="angle">The angle in degrees clockwise from the x-axis that this RotatedRectangleF is rotated.</param>
    ''' <remarks></remarks>
    Sub New(ByVal centre As PointF, ByVal size As SizeF, ByVal angle As Single)
        Me.Centre = centre
        Me.Size = size
        Me.Angle = angle
    End Sub

    ''' <summary>
    ''' Render this RotatedRectangle using the provided System.Drawing.Graphics object.
    ''' </summary>
    ''' <param name="g">The System.Drawing.Graphics object with which to draw the RotatedRectangleF.</param>    
    Public Sub Render(ByVal g As Graphics, ByVal p As Pen)
        g.TranslateTransform(Me.Centre.X, Me.Centre.Y)
        g.RotateTransform(Me.Angle)
        g.DrawRectangle(p, -Me.Size.Width / 2.0F, -Me.Size.Height / 2.0F, Me.Size.Width, Me.Size.Height)
        g.ResetTransform()
    End Sub

    ''' <summary>
    ''' Determines whether two RotatedRectangleF structures intersect.
    ''' </summary>
    ''' <param name="rr1">The first RotatedRectangleF structure.</param>
    ''' <param name="rr2">The second RotatedRectangleF structure.</param>
    ''' <returns>True if the two RotatedRectangleF structures intersect, False otherwise.</returns>
    ''' <remarks>
    ''' Conversion of code by Oren Becker, 2001
    ''' http://www.ragestorm.net/tutorial?id=22
    ''' </remarks>
    Public Shared Function Intersect(ByVal rr1 As RotatedRectangleF, ByVal rr2 As RotatedRectangleF) As Boolean

        ' Change our structure to match the one in the other code.
        ' Angle in radians, size is (width / 2, height / 2)
        rr1 = New RotatedRectangleF(rr1.Centre, New SizeF(rr1.Size.Width / 2, rr1.Size.Height / 2), DegreesToRadians(rr1.Angle))
        rr2 = New RotatedRectangleF(rr2.Centre, New SizeF(rr2.Size.Width / 2, rr2.Size.Height / 2), DegreesToRadians(rr2.Angle))

        Dim ang As Single = rr1.Angle - rr2.Angle ' orientation of rotated rr1
        Dim cosA As Single = CType(Math.Cos(ang), Single) ' precalculated trigonometic -
        Dim sinA As Single = CType(Math.Sin(ang), Single) ' - values for repeated use

        Dim x, a1 As Single ' temporary variables for various uses 
        Dim dx As Single ' deltaX for linear equations
        Dim ext1, ext2 As Single ' // min/max vertical values

        ' move rr2 to make rr1 cannonic        
        Dim C As New PointF(rr2.Centre.X - rr1.Centre.X, rr2.Centre.Y - rr1.Centre.Y)

        ' rotate rr2 clockwise by rr2->ang to make rr2 axis-aligned
        RotatePointFClockwise(C, rr2.Angle)        

        ' calculate vertices of (moved and axis-aligned := 'ma') rr2
        Dim BL As PointF = C - rr2.Size        
        Dim TR As PointF = C + rr2.Size

        ' calculate vertices of (rotated := 'r') rr1
        Dim A, B As PointF ' vertices of rr2   
        A.X = -rr1.Size.Height * sinA
        B.X = A.X
        Dim temp1 As Single = rr1.Size.Width * cosA
        A.X = A.X + temp1
        B.X = B.X - temp1

        A.Y = rr1.Size.Height * cosA
        B.Y = A.Y
        temp1 = rr1.Size.Width * sinA
        A.Y = A.Y + temp1
        B.Y = B.Y - temp1

        temp1 = sinA * cosA

        ' verify that A is vertical min/max, B is horizontal min/max
        If temp1 < 0 Then
            temp1 = A.X
            A.X = B.X
            B.X = temp1
            temp1 = A.Y
            A.Y = B.Y
            B.Y = temp1
        End If

        ' verify that B is horizontal minimum (leftest-vertex)
        If sinA < 0 Then
            B.X = -B.X
            B.Y = -B.Y
        End If

        ' if rr2(ma) isn't in the horizontal range of
        ' colliding with rr1(r), collision is impossible
        If (B.X > TR.X) OrElse (B.X > -BL.X) Then Return False

        ' if rr1(r) is axis-aligned, vertical min/max are easy to get
        If (temp1 = 0) Then
            ext1 = A.Y
            ext2 = -ext1
        Else
            ' else, find vertical min/max in the range [BL.x, TR.x]
            x = BL.X - A.X
            a1 = TR.X - A.X
            ext1 = A.Y
            ' if the first vertical min/max isn't in (BL.x, TR.x), then
            ' find the vertical min/max on BL.x or on TR.x
            If a1 * x > 0 Then
                dx = A.X
                If x < 0 Then
                    dx -= B.X
                    ext1 -= B.Y
                    x = a1
                Else
                    dx += B.X
                    ext1 += B.Y
                End If
                ext1 *= x
                ext1 /= dx
                ext1 += A.Y
            End If

            x = BL.X + A.X
            a1 = TR.X + A.X
            ext2 = -A.Y
            ' if the second vertical min/max isn't in (BL.x, TR.x), then
            ' find the local vertical min/max on BL.x or on TR.x
            If a1 * x > 0 Then
                dx = -A.X
                If x < 0 Then
                    dx -= B.X
                    ext2 -= B.Y
                    x = a1
                Else
                    dx += B.X
                    ext2 += B.Y
                End If
                ext2 *= x
                ext2 /= dx
                ext2 -= A.Y
            End If
        End If

        ' check whether rr2(ma) is in the vertical range of colliding with rr1(r)
        ' (for the horizontal range of rr2)
        Return Not ((ext1 < BL.Y AndAlso ext2 < BL.Y) OrElse (ext1 > TR.Y AndAlso ext2 > TR.Y))
    End Function

    Private Shared Function DegreesToRadians(ByVal degrees As Single) As Single
        Return degrees * Pi / 180
    End Function

    Private Shared Sub RotatePointFClockwise(ByRef point As PointF, ByVal radians As Single)
        Dim temp As Single = point.X
        Dim cosAngle As Single = CType(Math.Cos(radians), Single)
        Dim sinAngle As Single = CType(Math.Sin(radians), Single)
        point.X = temp * cosAngle + point.Y * sinAngle
        point.Y = -temp * sinAngle + point.Y * cosAngle
    End Sub

    Public Shared Operator =(ByVal rr1 As RotatedRectangleF, ByVal rr2 As RotatedRectangleF) As Boolean
        Return (rr1.Centre = rr2.Centre) AndAlso (rr1.Angle = rr2.Angle) AndAlso (rr1.Size = rr2.Size)
    End Operator

    Public Shared Operator <>(ByVal rr1 As RotatedRectangleF, ByVal rr2 As RotatedRectangleF) As Boolean
        Return Not (rr1 = rr2)
    End Operator

End Structure

And a Form1.vb to demonstrate it:

Imports System.Drawing.Drawing2D

Public Class Form1

    Private selected As Integer = 1
    Private rec1 As New RotatedRectangleF(New PointF(50, -150), New SizeF(100, 100), 10)
    Private rec2 As New RotatedRectangleF(New Point(50, -200), New SizeF(25, 100), 55)
    Private message As String
    Private messageFont As New Font("Courier New", 10, FontStyle.Regular)
    Private selectedRectanglePen As Pen = Pens.Red
    Private unselectedRectanglePen As Pen = Pens.Black

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        message = "Arrow keys / mouse down to move" & vbCrLf
        message &= "Space to select other rectangle." & vbCrLf
        message &= "z x / mouse wheel to rotate."
        Me.DoubleBuffered = True
        Me.ClientSize = New Size(800, 800)
        Me.Text = RotatedRectangleF.Intersect(rec1, rec2).ToString
    End Sub

    Private Sub Form1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
        Select Case e.KeyData
            Case Keys.Left
                MoveSelectedHorizontally(-1)
            Case Keys.Right
                MoveSelectedHorizontally(1)
            Case Keys.Up
                MoveSelectedVertically(-1)
            Case Keys.Down
                MoveSelectedVertically(1)
            Case Keys.Z
                RotateSelected(-1)
            Case Keys.X
                RotateSelected(1)
            Case Keys.Space
                If selected = 1 Then
                    selected = 2
                Else
                    selected = 1
                End If
                Me.Refresh()
        End Select
    End Sub

    Private Sub MouseDidSomething(ByVal sender As Object, ByVal e As MouseEventArgs) Handles Me.MouseMove, Me.MouseDown
        If e.Button = Windows.Forms.MouseButtons.Left Then
            Dim pos As New PointF(CSng(e.X - Me.ClientSize.Width / 2), CSng(e.Y - Me.ClientSize.Height / 2))
            If selected = 1 Then
                rec1.Centre = pos
            Else
                rec2.Centre = pos
            End If
            Me.Refresh()
            Me.Text = RotatedRectangleF.Intersect(rec1, rec2).ToString
        End If
    End Sub

    Private Sub Form1_MouseWheel(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseWheel
        If e.Delta > 0 Then
            RotateSelected(1)
        Else
            RotateSelected(-1)
        End If
    End Sub

    Private Sub RotateSelected(ByVal change As Single)
        If selected = 1 Then
            rec1.Angle += change
        Else
            rec2.Angle += change
        End If
        Me.Refresh()
        Me.Text = RotatedRectangleF.Intersect(rec1, rec2).ToString
    End Sub

    Private Sub MoveSelectedHorizontally(ByVal change As Single)
        If selected = 1 Then
            rec1.Centre = New PointF(rec1.Centre.X + change, rec1.Centre.Y)
        Else
            rec2.Centre = New PointF(rec2.Centre.X + change, rec2.Centre.Y)
        End If
        Me.Refresh()
        Me.Text = RotatedRectangleF.Intersect(rec1, rec2).ToString
    End Sub

    Private Sub MoveSelectedVertically(ByVal change As Single)
        If selected = 1 Then
            rec1.Centre = New PointF(rec1.Centre.X, rec1.Centre.Y + change)
        Else
            rec2.Centre = New PointF(rec2.Centre.X, rec2.Centre.Y + change)
        End If
        Me.Refresh()
        Me.Text = RotatedRectangleF.Intersect(rec1, rec2).ToString
    End Sub

    Private Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint
        e.Graphics.DrawString(message, messageFont, Brushes.Gray, 10, 10)
        e.Graphics.TranslateTransform(Me.ClientSize.Width \ 2, Me.ClientSize.Height \ 2)
        e.Graphics.DrawLine(Pens.Gray, -Me.ClientSize.Width \ 2, 0, Me.ClientSize.Width \ 2, 0)
        e.Graphics.DrawLine(Pens.Gray, 0, -Me.ClientSize.Height \ 2, 0, +Me.ClientSize.Height \ 2)
        Dim store As Matrix = e.Graphics.Transform
        If selected = 1 Then
            rec2.Render(e.Graphics, unselectedRectanglePen)
            e.Graphics.Transform = store
            rec1.Render(e.Graphics, selectedRectanglePen)
        Else
            rec1.Render(e.Graphics, unselectedRectanglePen)
            e.Graphics.Transform = store
            rec2.Render(e.Graphics, selectedRectanglePen)
        End If
    End Sub

    

End Class

VB.Net - Enumerate the windows update history using the windows update api

2009-02-02T04:10:00.006Z

Someone in the forum wanted to get the Description for each windows update, and WMI/the registry were no help. They were going to try to dig the information out of "C:\Windows\SoftwareDistribution\DataStore\DataStore.edb", which is undocumented. Some people say it is a Jet database, but I'm not sure. Exchange server uses that extension too.

Anyway the windows update api will do it. This pic shows the interfaces involved:

First you need to get an IUpdateSession. That has a CreateUpdateSearcher method to get an IUpdateSearcher. That has GetTotalHistoryCount to get the number of IUpdateHistoryEntry items inside the IUpdateHistoryCollection. To get the collection you call QueryHistory on the IUpdateSearcher, passing in the count from before. Each IUpdateHistoryEntry has a bunch of properties, some of which have custom types, but they are all simple to retrieve. To get your hands on the interfaces, the easiest way is to use tlbimp from the Visual studio command line (or the one with the platform sdk, or the one with the framework sdk). Copy the wuapi.dll file from .../Windows/System32 to some directory of your choice, navigate there and run...
tlbimp.exe wuapi.dll /out=WUApiInterop.dll

This creates managed signatures for all the COM interfaces in wuapi.dll and sticks them in WuApiInterop.dll. You can then create a windows forms project, add a reference to WuApiInterop.dll and get your paws on all the interfaces. I made a .Net dll that has a friendly version of the IUpdateHistoryEntry object, and a method to return a collection of them. This is the code that gets the information.

    <SecurityPermission(SecurityAction.LinkDemand, Flags:=SecurityPermissionFlag.UnmanagedCode)> _
    Public Shared Function GetHistory() As ReadOnlyCollection(Of HistoryItem)
        Dim session As UpdateSession = Nothing
        Dim searcher As IUpdateSearcher = Nothing
        Try
            session = New UpdateSession
            If session Is Nothing Then Throw New InvalidOperationException("Couln't create an IUpdateSearcher.")
            searcher = session.CreateUpdateSearcher
        Finally
            If session IsNot Nothing Then Marshal.ReleaseComObject(session)
        End Try
        If searcher Is Nothing Then Throw New InvalidOperationException("Couldn't create an IUpdateSession.")
        Dim count As Integer = searcher.GetTotalHistoryCount
        If count = 0 Then
            Return New ReadOnlyCollection(Of HistoryItem)(Nothing)
        End If
        Dim historyCollection As IUpdateHistoryEntryCollection = Nothing
        Try
            historyCollection = searcher.QueryHistory(0, count)
        Finally
            Marshal.ReleaseComObject(searcher)
        End Try
        If historyCollection Is Nothing Then Throw New InvalidOperationException("Couldn't get an IUpdateHistoryEntryCollection.")
        Dim items As New List(Of HistoryItem)(count)
        Try
            For i As Integer = 0 To count - 1
                Dim item As IUpdateHistoryEntry = historyCollection.Item(i)
                Dim friendlyItem As New HistoryItem
                With friendlyItem
                    .ClientApplicationId = item.ClientApplicationID
                    .Date = item.Date
                    .Description = item.Description
                    .HResult = item.HResult
                    Select Case item.Operation
                        Case WUApiInterop.UpdateOperation.uoInstallation
                            .Operation = UpdateOperation.Installation
                        Case WUApiInterop.UpdateOperation.uoUninstallation
                            .Operation = UpdateOperation.Uninstallation
                    End Select
                    Select Case item.ResultCode
                        Case WUApiInterop.OperationResultCode.orcAborted
                            .ResultCode = OperationResultCode.Aborted
                        Case WUApiInterop.OperationResultCode.orcFailed
                            .ResultCode = OperationResultCode.Failed
                        Case WUApiInterop.OperationResultCode.orcInProgress
                            .ResultCode = OperationResultCode.InProgress
                        Case WUApiInterop.OperationResultCode.orcNotStarted
                            .ResultCode = OperationResultCode.NotStarted
                        Case WUApiInterop.OperationResultCode.orcSucceeded
                            .ResultCode = OperationResultCode.Succeeded
                        Case WUApiInterop.OperationResultCode.orcSucceededWithErrors
                            .ResultCode = OperationResultCode.SucceededWithErrors
                    End Select
                    Select Case item.ServerSelection
                        Case WUApiInterop.ServerSelection.ssDefault
                            .ServerSelection = ServerSelection.Default
                        Case WUApiInterop.ServerSelection.ssManagedServer
                            .ServerSelection = ServerSelection.ManagedServer
                        Case WUApiInterop.ServerSelection.ssOthers
                            .ServerSelection = ServerSelection.Others
                        Case WUApiInterop.ServerSelection.ssWindowsUpdate
                            .ServerSelection = ServerSelection.WindowsUpdate
                    End Select
                    .ServiceId = item.ServiceID
                    Uri.TryCreate(item.SupportUrl, UriKind.Absolute, .SupportUrl)
                    .Title = item.Title
                    .UninstallationNotes = item.UninstallationNotes
                    .UninstallationSteps = New System.Collections.Specialized.StringCollection
                    For j As Integer = 0 To item.UninstallationSteps.Count - 1
                        .UninstallationSteps.Add(item.UninstallationSteps(j))
                    Next
                    .UnmappedResultCode = item.UnmappedResultCode
                    Dim identity As New UpdateIdentity(item.UpdateIdentity.RevisionNumber, item.UpdateIdentity.UpdateID)
                    .UpdateIdentity = identity
                End With
                items.Add(friendlyItem)
            Next
        Finally
            Marshal.ReleaseComObject(historyCollection)
        End Try
        Return New ReadOnlyCollection(Of HistoryItem)(items)
    End Function

Attached is an example project:

Set default Wave Out Audio Device - VB.Net / DRVM_MAPPER_PREFERRED_SET

2009-01-23T16:05:00.003Z

You can set the default audio playback device in windows 2000, Me, and XP with the DRVM_MAPPER_PREFERRED_SET message, which is sent with waveOutMessage().

It doesn't work on vista - you get MMSYSERR_NOTSUPPORTED (8), returned.
You can do it in Vista - see http://vachanger.sourceforge.net/

Anyway, the code uses the Windows Media .Net library.

Imports MultiMedia ' http://windowsmedianet.sourceforge.net/
Imports System.Runtime.InteropServices
Imports System.ComponentModel

Public Class Form1

    Private DevicesComboBox As New ComboBox
    Private DefaultDeviceLabel As New Label
    Private WithEvents SetDefaultButton As New Button
    Private Const DRVM_MAPPER_PREFERRED_GET As Integer = &H2015
    Private Const DRVM_MAPPER_PREFERRED_SET As Integer = &H2016
    Private WAVE_MAPPER As New IntPtr(-1)

    ' This just brings together a device ID and a WaveOutCaps so 
    ' that we can store them in a combobox.
    Private Structure WaveOutDevice

        Private m_id As Integer
        Public Property Id() As Integer
            Get
                Return m_id
            End Get
            Set(ByVal value As Integer)
                m_id = value
            End Set
        End Property

        Private m_caps As WaveOutCaps
        Public Property WaveOutCaps() As WaveOutCaps
            Get
                Return m_caps
            End Get
            Set(ByVal value As WaveOutCaps)
                m_caps = value
            End Set
        End Property

        Sub New(ByVal id As Integer, ByVal caps As WaveOutCaps)
            m_id = id
            m_caps = caps
        End Sub

        Public Overrides Function ToString() As String
            Return WaveOutCaps.szPname
        End Function

    End Structure

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        ' I do use the IDE for this stuff normally... (in case anyone is wondering)
        Me.Controls.AddRange(New Control() {DevicesComboBox, DefaultDeviceLabel, SetDefaultButton})
        DevicesComboBox.Location = New Point(5, 5)
        DevicesComboBox.DropDownStyle = ComboBoxStyle.DropDownList
        DevicesComboBox.Width = Me.ClientSize.Width - 10
        DevicesComboBox.Anchor = AnchorStyles.Left Or AnchorStyles.Right
        DefaultDeviceLabel.Location = New Point(DevicesComboBox.Left, DevicesComboBox.Bottom + 5)
        DefaultDeviceLabel.AutoSize = True
        SetDefaultButton.Location = New Point(DefaultDeviceLabel.Left, DefaultDeviceLabel.Bottom + 5)
        SetDefaultButton.Text = "Set Default"
        SetDefaultButton.AutoSize = True
        RefreshInformation()
    End Sub

    Private Sub RefreshInformation()
        PopulateDeviceComboBox()
        DisplayDefaultWaveOutDevice()
    End Sub

    Private Sub PopulateDeviceComboBox()
        DevicesComboBox.Items.Clear()
        ' How many wave out devices are there? WaveOutGetNumDevs API call.
        Dim waveOutDeviceCount As Integer = waveOut.GetNumDevs()
        For i As Integer = 0 To waveOutDeviceCount - 1
            Dim caps As New WaveOutCaps
            ' Get a name - its in a WAVEOUTCAPS structure. 
            ' The name is truncated to 31 chars by the api call. You probably have to 
            ' dig around in the registry to get the full name.
            Dim result As Integer = waveOut.GetDevCaps(i, caps, Marshal.SizeOf(caps))
            If result <> MMSYSERR.NoError Then
                Dim err As MMSYSERR = DirectCast(result, MMSYSERR)
                Throw New Win32Exception("GetDevCaps() error, Result: " & result.ToString("x8") & ", " & err.ToString)
            End If
            DevicesComboBox.Items.Add(New WaveOutDevice(i, caps))
        Next
        DevicesComboBox.SelectedIndex = 0
    End Sub

    Private Sub DisplayDefaultWaveOutDevice()
        Dim currentDefault As Integer = GetIdOfDefaultWaveOutDevice()
        Dim device As WaveOutDevice = DirectCast(DevicesComboBox.Items(currentDefault), WaveOutDevice)
        DefaultDeviceLabel.Text = "Defualt: " & device.WaveOutCaps.szPname
    End Sub

    Private Function GetIdOfDefaultWaveOutDevice() As Integer        
        Dim id As Integer = 0
        Dim hId As IntPtr
        Dim flags As Integer = 0
        Dim hFlags As IntPtr
        Dim result As Integer
        Try
            ' It would be easier to declare a nice overload with ByRef Integers.
            hId = Marshal.AllocHGlobal(4)
            hFlags = Marshal.AllocHGlobal(4)
            ' http://msdn.microsoft.com/en-us/library/bb981557.aspx
            result = waveOut.Message(WAVE_MAPPER, DRVM_MAPPER_PREFERRED_GET, hId, hFlags)
            If result <> MMSYSERR.NoError Then
                Dim err As MMSYSERR = DirectCast(result, MMSYSERR)
                Throw New Win32Exception("waveOutMessage() error, Result: " & result.ToString("x8") & ", " & err.ToString)
            End If
            id = Marshal.ReadInt32(hId)
            flags = Marshal.ReadInt32(hFlags)
        Finally
            Marshal.FreeHGlobal(hId)
            Marshal.FreeHGlobal(hFlags)
        End Try
        ' There is only one flag, DRVM_MAPPER_PREFERRED_FLAGS_PREFERREDONLY, defined as 1
        ' "When the DRVM_MAPPER_PREFERRED_FLAGS_PREFERREDONLY flag bit is set, ... blah ...,  
        ' the waveIn and waveOut APIs use only the current preferred device and do not search 
        ' for other available devices if the preferred device is unavailable. 
        Return id
    End Function

    Private Sub SetDefaultButton_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles SetDefaultButton.Click
        If DevicesComboBox.Items.Count = 0 Then Return
        Dim selectedDevice As WaveOutDevice = DirectCast(DevicesComboBox.SelectedItem, WaveOutDevice)
        SetDefault(selectedDevice.Id)
        RefreshInformation()
    End Sub

    Private Sub SetDefault(ByVal id As Integer)
        Dim defaultId As Integer = GetIdOfDefaultWaveOutDevice()
        If defaultId = id Then Return ' no change.
        Dim result As Integer
        ' So here we say "change the Id of the device that has id id to 0", which makes it the default.
        result = waveOut.Message(WAVE_MAPPER, DRVM_MAPPER_PREFERRED_SET, New IntPtr(id), IntPtr.Zero)
        If result <> MMSYSERR.NoError Then
            Dim err As MMSYSERR = DirectCast(result, MMSYSERR)
            Throw New Win32Exception("waveOutMessage() error, Result: " & result.ToString("x8") & ", " & err.ToString)
        End If
    End Sub

End Class

Enable/Disable a device programmatically with VB.Net using the setup api.

2009-01-15T04:45:00.002Z

Very quickly...

Check in device manager to see if the device has "Disable" as an option when you R click it. If so then look at the properties, and find the "class guid" and "device instance id".

1) Get a handle to a device info set using SetupDiGetClassDevs - this will get all devices in a class.
2) Get device info data for each device in the class using SetupDiEnumDeviceInfo
3) Get the device instance id for each device using the device info data from (2) and SetupDiGetDeviceInstanceId.
4) Fill in a structure to say you want a property change and call SetupDiSetClassInstallParams. This sets the property in the device info set.
5) Call SetupDiCallClassInstaller to get the installer to make the changes stick.

Font choice -> dumb bug

2009-01-09T05:28:00.001Z

Oh wonderful. I thought I was doing something seriously wrong whilst trying to record sound. WaveInOpen takes a flag value, I wanted to specify that it should callback a function and read it as:

#define CALLBACK_FUNCTION   0x000300001

where it is actually

#define CALLBACK_FUNCTION   0x00030000l

Big difference eh. 1 vs L. The L specifies a C Long (32 bit integer).

I ended up sending two flags then, 0x300000 and 0x1. 0x1 tells it to just query - "can the device be opened" - without actually opening it. 0x300000 isn't defined. In testing it did call my callback function about 1 time in 3, the other 2 times it just crashed without error. So I though it was because I was doing the wrong thing in the callback. Argh.

Make a bootable USB Flash Drive from a floppy image file (VB.Net)

2008-12-28T20:30:00.002Z

To do this you just need a handle to the drive (the device handle), and then use WriteFile to copy the image to the drive. Here's a rough example.

At the moment it rounds the byte array containing the image file up to the nearest 512 bytes, as otherwise it returns "invalid parameter".

Imports System.IO
Imports System.Text

Public Class Form1

    Private sourceFile As FileInfo

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
        RefreshDrives()
    End Sub

    Private Sub btnBrowse_Click(ByVal sender As Object, ByVal e As EventArgs) _
        Handles btnBrowse.Click
        Using ofd As New OpenFileDialog
            ofd.Title = "Select disk image file"
            ofd.Multiselect = False
            Dim result As DialogResult = ofd.ShowDialog
            If result = Windows.Forms.DialogResult.OK Then
                Try
                    sourceFile = New FileInfo(ofd.FileName)
                Catch ex As Exception
                    MessageBox.Show(ex.Message)
                    sourceFile = Nothing
                End Try
            End If
        End Using
        If sourceFile IsNot Nothing Then
            Me.TextBox1.Text = sourceFile.ToString
        End If
        RefreshBtn_Nuke()
    End Sub

    Private Sub btnRefresh_Click(ByVal sender As Object, ByVal e As EventArgs) _
        Handles btnRefresh.Click
        RefreshDrives()
    End Sub

    Private Sub RefreshDrives()
        Me.ComboBox1.Items.Clear()
        For Each di As DriveInfo In DriveInfo.GetDrives
            If di.DriveType = DriveType.Removable Then
                Me.ComboBox1.Items.Add(di)
            End If
        Next
        Me.ComboBox1.SelectedIndex = 0
        RefreshBtn_Nuke()
    End Sub

    Private Sub RefreshBtn_Nuke()
        btnNuke.Enabled = (sourceFile IsNot Nothing) AndAlso _
            Me.ComboBox1.Items.Count > 0
    End Sub

    Private Sub btnNuke_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnNuke.Click
        Dim result As DialogResult
        Dim drive As String = Me.ComboBox1.Text
        Dim sb As New StringBuilder
        sb.AppendLine("Do you really want to erase drive " & drive & "?")
        sb.AppendLine("Doing so will DESTROY ALL EXISTING DATA ON DRIVE " & drive & "!")
        result = MessageBox.Show(sb.ToString, _
                                 "Destroy Drive " & drive & " ?", _
                                 MessageBoxButtons.YesNo, _
                                MessageBoxIcon.Exclamation, _
                                 MessageBoxDefaultButton.Button2)
        If result = Windows.Forms.DialogResult.Yes Then
            Dim dest As DriveInfo = TryCast(Me.ComboBox1.SelectedItem, DriveInfo)
            If sourceFile IsNot Nothing AndAlso dest IsNot Nothing Then
                Dim written As Integer = Win32.CopyToDevice(sourceFile, dest)
                MessageBox.Show("Wrote: " & written & " bytes to " & drive, "Done", _
                                MessageBoxButtons.OK, MessageBoxIcon.Information)
                Application.Exit()
            Else
                RefreshBtn_Nuke()
            End If
        End If
    End Sub

End Class

Option Strict On
Option Explicit On

Imports Microsoft.Win32.SafeHandles
Imports System.ComponentModel
Imports System.IO
Imports System.Runtime.InteropServices

Public Class Win32

    Private Const GenericRead As UInteger = &H80000000UI
    Private Const GenericWrite As UInteger = &H40000000
    Private Const FileShareRead As UInteger = 1
    Private Const Filesharewrite As UInteger = 2
    Private Const OpenExisting As UInteger = 3
    Private Const IoctlVolumeGetVolumeDiskExtents As UInteger = &H560000
    Private Const IncorrectFunction As UInteger = 1
    Private Const ErrorInsufficientBuffer As UInteger = 122

    Private Class NativeMethods
        <DllImport("kernel32", CharSet:=CharSet.Unicode, SetLastError:=True)> _
        Public Shared Function CreateFile( _
            ByVal fileName As String, _
            ByVal desiredAccess As UInteger, _
            ByVal shareMode As UInteger, _
            ByVal securityAttributes As IntPtr, _
            ByVal creationDisposition As UInteger, _
            ByVal flagsAndAttributes As UInteger, _
            ByVal hTemplateFile As IntPtr) As SafeFileHandle
        End Function

        <DllImport("kernel32", SetLastError:=True)> _
        Public Shared Function DeviceIoControl( _
            ByVal hVol As SafeFileHandle, _
            ByVal controlCode As UInteger, _
            ByVal inBuffer As IntPtr, _
            ByVal inBufferSize As Integer, _
            ByRef outBuffer As DiskExtents, _
            ByVal outBufferSize As Integer, _
            ByRef bytesReturned As Integer, _
            ByVal overlapped As IntPtr) As <MarshalAs(UnmanagedType.Bool)> Boolean
        End Function

        <DllImport("kernel32", SetLastError:=True)> _
        Public Shared Function DeviceIoControl( _
            ByVal hVol As SafeFileHandle, _
            ByVal controlCode As UInteger, _
            ByVal inBuffer As IntPtr, _
            ByVal inBufferSize As Integer, _
            ByVal outBuffer As IntPtr, _
            ByVal outBufferSize As Integer, _
            ByRef bytesReturned As Integer, _
            ByVal overlapped As IntPtr) As <MarshalAs(UnmanagedType.Bool)> Boolean
        End Function

        <DllImport("kernel32", SetLastError:=True)> _
        Public Shared Function SetFilePointer( _
            ByVal hFile As SafeFileHandle, _
            ByVal lDistanceToMove As Integer, _
            ByRef lpDistanceToMoveHigh As Integer, _
            ByVal dwMoveMethod As Integer) As UInteger
        End Function

        ' you must write the whole inBuffer.
        <DllImport("kernel32", SetLastError:=True, CharSet:=CharSet.Ansi)> _
        Public Shared Function WriteFile( _
          ByVal hVol As SafeFileHandle, _
          <MarshalAs(UnmanagedType.LPArray, SizeParamIndex:=3)> _
          ByVal inBuffer() As Byte, _
          ByVal numberOfBytesToWrite As Integer, _
          ByRef numberOfBytesWritten As Integer, _
          ByVal overlapped As IntPtr) As <MarshalAs(UnmanagedType.Bool)> Boolean
        End Function

    End Class

    ' DISK_EXTENT in the msdn.
    <StructLayout(LayoutKind.Sequential)> _
    Private Structure DiskExtent
        Public DiskNumber As Integer
        Public StartingOffset As Long
        Public ExtentLength As Long
    End Structure

    ' DISK_EXTENTS
    <StructLayout(LayoutKind.Sequential)> _
    Private Structure DiskExtents
        Public numberOfExtents As Integer
        Public first As DiskExtent ' We can't marhsal an array if we don't know its size.
    End Structure

    Public Shared Function CopyToDevice(ByVal source As FileInfo, _
                                        ByVal destination As DriveInfo) As Integer
        Dim physicalDrives As List(Of String) = GetPhysicalDriveStrings(destination)
        If physicalDrives.Count > 1 Then
            Throw New Exception("The volume spans multiple disks!")
        End If
        If physicalDrives.Count = 0 Then
            Throw New Exception("Could not find the physical drive!")
        End If
        Dim physicalDrive As String = physicalDrives(0)
        Dim sourceFile As String = source.FullName
        Dim driveHandle As SafeFileHandle = Nothing
        Try
            driveHandle = NativeMethods.CreateFile( _
                physicalDrive, GenericRead Or GenericWrite, _
                FileShareRead Or Filesharewrite, _
                IntPtr.Zero, OpenExisting, 0, IntPtr.Zero)
            Dim bytes() As Byte = My.Computer.FileSystem.ReadAllBytes(source.FullName)
            Dim remainder As Integer = 512 - (bytes.Length Mod 512)
            If remainder < 512 Then
                ReDim Preserve bytes(bytes.Length + remainder - 1)
            End If
            Dim written As Integer = 0
            NativeMethods.SetFilePointer(driveHandle, 0, 0, 0)
            Dim result As Boolean = NativeMethods.WriteFile(driveHandle, _
                bytes, bytes.Length, written, IntPtr.Zero)
            If result = False Then Throw New Win32Exception
            Return written
        Finally
            If driveHandle IsNot Nothing Then
                If driveHandle.IsInvalid = False Then
                    If driveHandle.IsClosed = False Then
                        driveHandle.Close()
                    End If
                End If
                driveHandle.Dispose()
            End If
        End Try

    End Function

    ' A Volume could be on many physical drives.
    ' Returns a list of string containing each physical drive the volume uses.
    ' For CD Drives with no disc in it will return an empty list.
    Public Shared Function GetPhysicalDriveStrings(ByVal driveInfo As DriveInfo) As List(Of String)
        Dim sfh As SafeFileHandle = Nothing
        Dim physicalDrives As New List(Of String)(1)
        Dim path As String = "\\.\" & driveInfo.RootDirectory.ToString.TrimEnd("\"c)
        Try
            sfh = NativeMethods.CreateFile(path, GenericRead, FileShareRead Or Filesharewrite, _
                                           IntPtr.Zero, OpenExisting, 0, IntPtr.Zero)
            Dim bytesReturned As Integer
            Dim de1 As DiskExtents = Nothing
            Dim numDiskExtents As Integer = 0
            Dim result As Boolean = NativeMethods.DeviceIoControl(sfh, _
                IoctlVolumeGetVolumeDiskExtents, IntPtr.Zero, 0, de1, Marshal.SizeOf(de1), _
                bytesReturned, IntPtr.Zero)
            If result = True Then
                ' there was only one disk extent. So the volume lies on 1 physical drive.
                physicalDrives.Add("\\.\PhysicalDrive" & de1.first.DiskNumber.ToString)
                Return physicalDrives
            End If
            If Marshal.GetLastWin32Error = IncorrectFunction Then
                ' The drive is removable and removed, like a CDRom with nothing in it.
                Return physicalDrives
            End If
            If Marshal.GetLastWin32Error <> ErrorInsufficientBuffer Then
                Throw New Win32Exception
            End If
            ' The volume is on multiple disks.
            ' Untested...
            ' We need a blob of memory for the DISK_EXTENTS structure, and all the DISK_EXTENTS
            Dim blobSize As Integer = Marshal.SizeOf(GetType(DiskExtents)) + _
                                      (de1.numberOfExtents - 1) * _
                                      Marshal.SizeOf(GetType(DiskExtent))
            Dim pBlob As IntPtr = Marshal.AllocHGlobal(blobSize)
            result = NativeMethods.DeviceIoControl(sfh, IoctlVolumeGetVolumeDiskExtents, _
                IntPtr.Zero, 0, pBlob, blobSize, bytesReturned, IntPtr.Zero)
            If result = False Then Throw New Win32Exception
            ' Read them out one at a time.
            Dim pNext As New IntPtr(pBlob.ToInt32 + 4) ' is this always ok on 64 bit OSes? ToInt64?
            For i As Integer = 0 To de1.numberOfExtents - 1
                Dim diskExtentN As DiskExtent = DirectCast(Marshal.PtrToStructure(pNext, _
                    GetType(DiskExtent)), DiskExtent)
                physicalDrives.Add("\\.\PhysicalDrive" & diskExtentN.DiskNumber.ToString)
                pNext = New IntPtr(pNext.ToInt32 + Marshal.SizeOf(GetType(DiskExtent)))
            Next
            Return physicalDrives
        Finally
            If sfh IsNot Nothing Then
                If sfh.IsInvalid = False Then
                    sfh.Close()
                End If
                sfh.Dispose()
            End If
        End Try
    End Function


End Class

VB.Net enumerate the system tray icons/buttons

2008-12-24T01:59:00.002Z

Another msdn post. This one asked how to get the paths to the icons in the system tray. This sounds pretty simple, but isn't. You can start off by finding the window with Spy++, and then getting a handle to it. Then SendMessage with TB_BUTTONCOUNT to get the number of buttons. (TBBUTTON = TaskBarButton). Then you send TB_GETBUTTON repeatedly and get back TBBUTTON structures with information about the buttons. (See the last blog post for info on the x86/x64 mess)

typedef struct _TBBUTTON {    int        iBitmap;
    int        idCommand;
    BYTE     fsState;
    BYTE     fsStyle;
#ifdef _WIN64
    BYTE     bReserved[6]     // padding for alignment
#elif defined(_WIN32)
    BYTE     bReserved[2]     // padding for alignment
#endif
   DWORD_PTR   dwData;
    INT_PTR          iString;
} TBBUTTON, NEAR *PTBBUTTON *LPTBBUTTON;

The dwData field points to a NOTIFYICONDATA structure with some more gobbledegook:

typedef struct _NOTIFYICONDATA {
    DWORD cbSize;
    HWND hWnd;
    UINT uID;
    UINT uFlags;
    UINT uCallbackMessage;
    HICON hIcon;
    TCHAR szTip[64];
    DWORD dwState;
    DWORD dwStateMask;
    TCHAR szInfo[256];
    union {
        UINT uTimeout;
        UINT uVersion;
    };
    TCHAR szInfoTitle[64];
    DWORD dwInfoFlags;
    GUID guidItem;
    HICON hBalloonIcon;
} NOTIFYICONDATA, *PNOTIFYICONDATA;

We don't need all that, so we could trim it down. Earlier versions of windows used a smaller version anyway.

The difficulty lies in the fact that some of the pointers don't point anywhere useful. Say my process has a button at address 100. That address is local to my process, it has its own virtual memory space. If another process reads that pointer, then the value - 100 - will not mean anything as the other process has its own virtual memory space that maps to a different block of real memory. In our program, we SendMessage to the process hosting the tray buttons asking it to stick a TBBUTTON structure into some memory that is allocated in our home process. Unfortunately the pointer to the memory has no meaning to the other process, so the button goes astray.

To get around this, we ask the other process to create a blob of memory big enough for a tray button using VirtualAllocEx. Then we SendMessage, asking the other process to put the button into this blob of memory. Finally we read the contents of that memory with ReadProcessMemory:

Dim tbb As New TBBUTTON32
Dim friendlyTB As New TrayButton
friendlyTB.SetTrayIndex(index)
Dim pButton As IntPtr = IntPtr.Zero
Try
    ' Create memory in the explorer process to store a TBBUTTON strucutre:
    pButton = VirtualAllocEx(hProcess, Nothing, tbb.Size, MEM_COMMIT, PAGE_READWRITE)
    ' Use SendMessage to request that the memory is filled with the TBBUTTON @ index.
    Dim bResult As Boolean = SendMessage(hwndTrayToolbar, TB_GETBUTTON, index, pButton)
    If bResult = False Then Throw New Win32Exception
    ' And read the memory from the other process:
    Dim bytesReturned As Integer
    bResult = ReadProcessMemory(hProcess, pButton, tbb, tbb.Size, bytesReturned)
    If bResult = False Then Throw New Win32Exception

And here's an app that doesn't work too well as there are many complications to do with animated icons, OSes, x86/x64 that I haven't touched...

Structures that vary in size on x86/x64 - what to do?

2008-12-24T00:56:00.002Z

Some structures can be difficult to marshal, as their size varies on x86 compared to x64:

typedef struct _TBBUTTON {
   int         iBitmap;
   int         idCommand;
   BYTE     fsState;
   BYTE     fsStyle;
#ifdef _WIN64
   BYTE     bReserved[6]     // padding for alignment
#elif defined(_WIN32)
   BYTE     bReserved[2]     // padding for alignment
#endif
   DWORD_PTR   dwData;
   INT_PTR          iString;
} TBBUTTON, NEAR *PTBBUTTON *LPTBBUTTON;

The layouts in x86 and x64 would look like this:

In C the standard is for, say, an int to stay within a 4 byte boundary of the start of the structure. A short would
not cross a 2 byte boundary. Bytes can go where they like (well, they shouldn't cross the byte boundary, which I
guess they could by having bits spread over 2 bytes!)

A pointer on x86 is a 4 byte value, and shouldn't cross a 4 byte boundary. A pointer on x64 is an 8 byte value, and
shouldn't cross an 8 byte boundary. Phew. Enough about byte boundaries...

TBBUTTON causes problems as it has the two BYTE fields in the middle. We need to pad, to get the dwData field
to start at a suitable location. Once it is in the correct place, iString will be fine.

With .Net we have a few ways to arrange structures. We can use StructLayout(LayoutKind.Sequential, Pack:=x).
Sequential means that .Net is not allowed to move the fields around at runtime, we want them to be arranged
in memory in the order that they appear in our declaration, this will match the C behaviour. Pack allows you to
specify the boundary to align the fields against. Often you would use sequential and pack = 1, then add fields of
padding to get it aligned.

Alternatively, you can use StructLayout(LayoutKind.Explicit) and hard-code where the fields should go. But,
this will only work if the structures have the same layout in x86 and x64. (Unfortunately you must use a
constant for the field offset, so you can't calculate it at runtime).

For TBBUTTON we are stuffed. There is no arrangement of pack and padding so that "one structure fits all", we will
need 2 declarations. And then we'll choose between them at runtime. (I think it might also be possible to just
compile it for x86 and run it under WOW64 on x64...)

<StructLayout(LayoutKind.Sequential, Pack:=1)> _
Public Structure TBBUTTON32
   Public bitmapIndex As Integer
   Public command As Integer
   Public state As TBStates
   Public style As TBStyles
   Public padding As UShort
   Public data As IntPtr
   Public iString As IntPtr
   Public Function Size() As Integer
       Return Marshal.SizeOf(Me)
   End Function
End Structure

<StructLayout(LayoutKind.Sequential, Pack:=1)> _
Public Structure TBBUTTON64
   Public bitmapIndex As Integer
   Public command As Integer
   Public state As TBStates
   Public style As TBStyles
   Public padding1 As Integer
   Public padding2 As UShort
   Public data As IntPtr
   Public iString As IntPtr
   Public Function Size() As Integer
       Return Marshal.SizeOf(Me)
   End Function
End Structure

The function is there for convenience. The 6 bytes of padding in the 64 bit version are spread across two variables.
We could equally use field offsets, but it takes a bit longer as you have to calculate them all. Unless you brain finds
that easy. My brain prefers arranging them in blocks and having padding bytes, and doesn't consider the numbers.

One thing that you think might work is the conditional compile thingy in VB.Net:

#if Platform="x86"

but this depends on the build target, it's not determined at runtime. So again, you would end up with two builds.

So, ...

2008-12-23T16:00:00.001Z

I must stop this. Looking back at my posts, and at forum posts it seems I start far too many new paragraphs with "So, ...". I wonder if it crept in to my TMAs?

Therefore, I will keep an eye out for it.

IOCTL_STORAGE_GET_MEDIA_SERIAL_NUMBER - VB.Net - might be incorrect

2008-12-23T01:32:00.003Z

For anyone trying to get IOCTL_STORAGE_GET_MEDIA_SERIAL_NUMBER to work. The following would return an error about the buffer being too small, if the device supports the call, and if I haven't made a mistake. I get "The request is not supported", which seems to be what other folks are saying. It seems no USB Flash drives actually support this call, I've tried with a secure sandisk one.

Option Strict On
Option Explicit On
Option Infer Off

Imports Microsoft.Win32.SafeHandles
Imports System.Runtime.InteropServices
Imports System.ComponentModel

Public Class Form1

  Private Const IOCTL_STORAGE_GET_MEDIA_SERIAL_NUMBER As UInteger = &HED0000

  <Flags()> _
  Private Enum AccessRights As UInteger
      GenericRead = &H80000000UI
      GenericWrite = &H40000000
      GenericExecute = &H20000000
      GenericAll = &H10000000
  End Enum

  <Flags()> _
  Private Enum ShareModes As UInteger
      FileShareRead = 1
      FileShareWrite = 2
      FileShareDelete = 4
  End Enum

  Private Enum CreationDisposition As UInteger
      CreateNew = 1
      CreateAlways = 2
      OpenExisting = 3
      OpenAlways = 4
      TruncateExisting = 5
  End Enum

  <StructLayout(LayoutKind.Sequential)> _
  Private Structure MediaSerialNumberData
      Public SerialNumberLength As UInteger
      Public Result As UInteger
      Public Reserved As UInt64
      Public SerialNumberData As Byte ' We would get the 1st byte, if any UFDs actually worked.
      Public Function Size() As Integer
          Return Marshal.SizeOf(Me)
      End Function
  End Structure

  <DllImport("kernel32", CharSet:=CharSet.Unicode, SetLastError:=True)> _
  Private Shared Function CreateFile( _
  ByVal fileName As String, _
  ByVal desiredAccess As AccessRights, _
  ByVal shareMode As ShareModes, _
  ByVal securityAttributes As IntPtr, _
  ByVal creationDisposition As CreationDisposition, _
  ByVal flagsAndAttributes As Integer, _
  ByVal hTemplateFile As IntPtr) As SafeFileHandle
  End Function

  <DllImport("kernel32", SetLastError:=True)> _
  Private Shared Function DeviceIoControl( _
  ByVal hVol As SafeFileHandle, _
  ByVal controlCode As UInteger, _
  ByVal inBuffer As IntPtr, _
  ByVal inBufferSize As Integer, _
  ByRef outBuffer As MediaSerialNumberData, _
  ByVal outBufferSize As Integer, _
  ByRef bytesReturned As Integer, _
  ByVal overlapped As IntPtr) As <MarshalAs(UnmanagedType.Bool)> Boolean
  End Function

  Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
      Dim sfh As SafeFileHandle = Nothing
      Try
          sfh = CreateFile("//./H:", AccessRights.GenericRead, _
                           ShareModes.FileShareRead Or _
                           ShareModes.FileShareWrite, _
                           IntPtr.Zero, _
                           CreationDisposition.OpenExisting, _
                           0, IntPtr.Zero)
          Dim msnd As New MediaSerialNumberData
          Dim returned As Integer
          Dim result As Boolean = DeviceIoControl(sfh, IOCTL_STORAGE_GET_MEDIA_SERIAL_NUMBER, _
                                                  IntPtr.Zero, 0, msnd, msnd.Size, returned, IntPtr.Zero)
          If result = False Then
              Console.WriteLine((New Win32Exception).Message)
          End If
      Catch ex As Exception
          Console.WriteLine(ex.Message)
      Finally
          If sfh IsNot Nothing Then
              If sfh.IsInvalid = False Then
                  If sfh.IsClosed = False Then
                      sfh.Close()
                  End If
              End If
              sfh.Dispose()
          End If
      End Try

  End Sub

End Class

M450 Project

2008-12-22T13:30:00.002Z

Well, I've signed up for my final 3 open university courses for the B29 degree. M450 (project), M359 (database), M363 (mishmash - seems to be mainly about requirements gathering, planning and design). And I'm straight in at the deep end, as there are only a few days left to come up with an M450 project idea.

The M450 bumph says we should spend about 300 hours on the course. The project must have some challenges - challenges that require looking at some papers! The 300 hours includes the time to answer the TMAs and do the research. So - nothing too complicated, and nothing too simple. It's hard to get something "just right". It also seems to be hinting that it is useful to have a client, or imaginary-client, so that we can assess the stages of development.

I had kept notes of interesting ideas whilst doing the AI course. I was interested in the idea of using a neural network to do colour quantisation - reduce the amount of colour information in a picture. But, I've discovered that is old-hat and it is even part of the java library. Groan.

Then I thought about doing a genetic algorithm to control some arcade game - snake and lunar lander were ideas as they are self-contained and simple games. But they have both been done. I kinda hoped to do a solver for the Times Killer Sudoku (soduku itself has been done to death), but there are now several solvers for that out there too. That would have been interesting - to compare all the different search and rules techniques. Then I thought about maybe rotating photos round the correct way using a neural network to detect the correct orientation. I figured that it wouldn't work for any old photo, so I would narrow it down to portraits or pictures of houses. For portraits, hopefully it would get the general idea that the blob of face colour should be somewhere in the top middle. For houses I thought of the scenario of an estate agent wanting to automatically rotate the images as they come in from the camera. (Why don't cameras have a built in spirit level and tag the images with the orientation? Patent the idea quick!!). The nn would be able to detect the block of sky. But - nope, that's been done to death too. I'm thinking that maybe finding any application for AI is a bit tricky.

So, that leaves the other choice - M362. There we could have some threading thing or go for a distributed application. I wrote a program to track patients psa blood test results. The idea is that the clinic is clogged up with gentlemen who come in, see the doctor, who glances at the blood results (which are taken to ensure that cancer has not recurred, if it has then the levels will be high), (s)he sees they are normal, has a bit of a chat about the weather and waves goodbye to the patient. This is a waste of time, "clinics cost money", and there are - of course - waiting lists to consider. The consultant needs to see the blood test, but not the patient. So, enter the program, it tracks the blood results and creates documents for the GP - to tell them the patient has entered remote follow up, to request that blood be taken, and to recall patients to clinic to be seen by the consultant. I wrote the standalone program a few years ago, and it was nominated for the HSJ awards this year (black tie dinner on Park Lane, don't'cha'know). We didn't win, I think we were short-listed to encourage other small projects that have a big effect (the program has saved the NHS at least £100,000), most of the other projects were on a bigger scale.

So, my proposal would be to investigate the use of JavaEE for the program. The hospital is interested in getting the program on the network, so I think that it would be a good opportunity to evaluate JavaEE. As the program itself is quite large, I would write a simplified version for the OU project - I would be creating a prototype n-tier version of the program. I would create a database, simplified logic, and concentrate on the web and client tier. None of the original program would be used, as it is in the wrong language, and old. But is this enough? What's the challenge? Which papers etc would I reference and work through? <sigh> Is creating a database application enough of a "challenge". Getting a program right is hard work, and I'll have to learn lots of new stuff - but I'll be investigating well-trodden paths and following well written instructions -- so is that good enough?

I've found an old board game that has little written about it on the web. I could only find 1 AI implementation for it, and that's a mac program - alien to me. Maybe I'll just do that. It might be more interesting. Research would be needed - all the papers on making AIs for chess, checkers, etc would be helpful. Writing the game itself would be half the challenge. There would be plenty of stuff to do and to talk about.

Time is running out, and Xmas is eating in to all my spare time.

Read SD Card CID (serial number)

2008-12-22T12:55:00.001Z

I just moved blogs, so here's an overview of the SD card CID stuff. I've had some success reading the CID from an SD Card:

Where:

1) The OS is XP or Vista 2) The device is not attached via any USB gizmo. It works only in a card reader attached directly to the PCI bus. (Can scsi pass through get around this? It's not an ATA or SCSI command...) 3) Admin privileges...

What not to do:

1) IOCTL_DISK_GET_STORAGEID 2) GetFileInformationByHandle

As both these return a number assigned when the volume is created. It will change next time the drive is formatted. What I did:

Use IOCTL_SFFDISK_DEVICE_COMMAND to send command 10 (see the SD spec).

Read Secure Digital (SD) Card Serial Number from CID

SD Card Musings

Read CID and CSD C# implementation

Pocket PC?

I don't think it works.

The Future?

IEEE 1667

Paste from Visual studio

2008-12-22T12:18:00.002Z

0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789

That's using the paste from visual studio plug-in for microsoft's live writer. Tells me the width of this blog. I can then make a guide line appear in the IDE using a registry hack, see

Sarah Ford's weblog - "Guidelines – a hidden feature for the Visual Studio Editor"

(I remember why I didn't use blogger originally -- there's not much room, and I can't be bothered to mess with the templates).

Moving to blogger

2008-12-22T12:03:00.002Z

I'm sick of Live spaces, as nothing turns up on google searches. Lets see how blogger compares. I'll probably use some of the live spaces facilities such as the file storage...

There will be a brief period of frenzied activity as I move some old posts here.

(Edit: Ok, moved and back dated, which is why this post makes little sense.)

Determine the layout of a structure for .Net Platform Invoke

2008-12-16T15:36:00.000Z

I was trying to create a signature for NOTIFYICONDATA, and decided to see what I could find out about it with C++.

1) start a new c++ CLR Console project in visual studio. Name it whatever you like. 2) Alter stdafx.h:

#pragma once
#define STRICT
#include <windows.h>   // common Win32 stuff
#include <commctrl.h>  // defines the structure we are interseted in
#include <stddef.h>    // we use offsetof
using namespace System;  // .Net types

3) in main, you can create a structure and determine its size. You can also find the offset for each field in the structure. Then you can swap the build to x64 and see what size they should be on x64 systems. This is definitely useful for when you want to create a managed C# or VB.Net version of the structure.

#include "stdafx.h"

using namespace System;

int main(array<System::String ^> ^args)
{
    NOTIFYICONDATA tbb;
    int i = sizeof(tbb);
    Console::WriteLine(i);   
    Console::WriteLine(offsetof(NOTIFYICONDATA,cbSize));
    Console::WriteLine(offsetof(NOTIFYICONDATA,hWnd));
    Console::WriteLine(offsetof(NOTIFYICONDATA,uID));
    Console::WriteLine(offsetof(NOTIFYICONDATA,uFlags));
    Console::WriteLine(offsetof(NOTIFYICONDATA,uCallbackMessage));
    Console::WriteLine(offsetof(NOTIFYICONDATA,hIcon));
    Console::WriteLine(offsetof(NOTIFYICONDATA,szTip));
    Console::WriteLine(offsetof(NOTIFYICONDATA,dwState));
    Console::WriteLine(offsetof(NOTIFYICONDATA,dwStateMask));
    Console::WriteLine(offsetof(NOTIFYICONDATA,szInfo));
    Console::WriteLine(offsetof(NOTIFYICONDATA,uTimeout));
    Console::WriteLine(offsetof(NOTIFYICONDATA,szInfoTitle));
    Console::WriteLine(offsetof(NOTIFYICONDATA,dwInfoFlags));
    Console::WriteLine(offsetof(NOTIFYICONDATA,guidItem));
    Console::WriteLine(offsetof(NOTIFYICONDATA,hBalloonIcon));
    Console::ReadKey();
    return 0;
}

Ugly, but it works.

Open University - story so far

2008-12-13T13:23:00.000Z

I can never find this:

Open university first class server address: oufcnt2.open.ac.uk This is handy:

B29 course calculator http://www.subrosauk.com/ou/b29grade.html

My results so far...

(OES/OCAS)

T175 "Networked living: exploring information and communication technologies" - (89/94)

MST121 "Using Mathematics" - (94/92)

M150 "Data, computing and information" - (OCAS 95)

M253 "Team working in distributed environments" - (78/86)

M255 "Object-oriented programming with Java" - (91/96) Distinction M256 "Software development with Java" - (86/95) Distinction M257 "Putting Java to work" - (87/96) Distinction

M263 "Building blocks of software" - (82/97) Distinction M362 "Developing concurrent distributed systems" - (88/95) Distinction

M366 "Natural and Artificial Intelligence" - (93/96) Distinction

Starting early 2009: M359 "Relational databases: theory and practice" M363 "Software engineering with objects" M450 "The computing project"

VB.Net Global keyboard hook to detect "print screen" keypress

2008-12-10T15:41:00.000Z

As described...

Option Strict On
Option Explicit On

Imports System.Runtime.InteropServices

Public Class Form1

    Private Const WH_KEYBOARD_LL As Integer = 13
    Private Const WM_KEYUP As Integer = &H101
    Private Const WM_SYSKEYUP As Integer = &H105
    Private proc As LowLevelKeyboardProcDelegate = AddressOf HookCallback
    Private hookID As IntPtr

    Private Delegate Function LowLevelKeyboardProcDelegate(ByVal nCode As Integer, ByVal wParam As IntPtr, _
        ByVal lParam As IntPtr) As IntPtr

    <DllImport("user32")> _
    Private Shared Function SetWindowsHookEx(ByVal idHook As Integer, ByVal lpfn As LowLevelKeyboardProcDelegate, _
        ByVal hMod As IntPtr, ByVal dwThreadId As UInteger) As IntPtr
    End Function

    <DllImport("user32.dll")> _
    Private Shared Function UnhookWindowsHookEx(ByVal hhk As IntPtr) As <MarshalAs(UnmanagedType.Bool)> Boolean
    End Function

    <DllImport("user32.dll")> _
    Private Shared Function CallNextHookEx(ByVal hhk As IntPtr, ByVal nCode As Integer, ByVal wParam As IntPtr, _
        ByVal lParam As IntPtr) As IntPtr
    End Function

    <DllImport("kernel32.dll", CharSet:=CharSet.Unicode)> _
    Private Shared Function GetModuleHandle(ByVal lpModuleName As String) As IntPtr
    End Function

    Sub New()
        ' This call is required by the Windows Form Designer.
        InitializeComponent()
        ' Add any initialization after the InitializeComponent() call.
        hookID = SetHook(proc)
    End Sub

    Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As FormClosingEventArgs) Handles Me.FormClosing
        UnhookWindowsHookEx(hookID)
    End Sub

    Private Function SetHook(ByVal proc As LowLevelKeyboardProcDelegate) As IntPtr
        Using curProcess As Process = Process.GetCurrentProcess()
            Using curModule As ProcessModule = curProcess.MainModule
                Return SetWindowsHookEx(WH_KEYBOARD_LL, proc, GetModuleHandle(curModule.ModuleName), 0)
            End Using
        End Using
    End Function

    Private Function HookCallback(ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As IntPtr
        ' we check keyup for standard printscreen, and syskeyup incase it is alt+printscreen
        ' we aren't checking keydown, as that fires before the screenshot is taken.
        If nCode >= 0 AndAlso (wParam.ToInt32 = WM_KEYUP OrElse wParam.ToInt32 = WM_SYSKEYUP) Then
            Dim vkCode As Integer = Marshal.ReadInt32(lParam)
            If vkCode = Keys.PrintScreen Then
                Dim data As IDataObject = Clipboard.GetDataObject()
                If data.GetDataPresent(GetType(Bitmap)) Then
                    Me.BackgroundImage = DirectCast(data.GetData(GetType(Bitmap)), Bitmap)
                End If
            End If
        End If
        Return CallNextHookEx(hookID, nCode, wParam, lParam)
    End Function

End Class

SetClipboardViewer API VB.NET

2008-12-10T12:00:00.000Z

This registers a form as a clipboard viewer. It then recieves notification when something happens to the clipboard. Some post on the msdn forum. It mentioned: http://www.radsoftware.com.au/articles/ClipboardMonitor_VB.txt, which I've tidied up to my liking (a stray long, a strange cast removed, you can't override Dispose (could you before?))

Option Strict On
Option Explicit On

Imports System.Runtime.InteropServices

Public Class Form1

   Private Const WM_DRAWCLIPBOARD As Integer = &H308
   Private Const WM_CHANGECBCHAIN As Integer = &H30D

   Private mNextClipBoardViewerHWnd As IntPtr
   Private Event OnClipboardChanged()

   <DllImport("user32")> _
   Private Shared Function SetClipboardViewer(ByVal hWnd As IntPtr) As IntPtr
   End Function

   <DllImport("user32")> _
   Private Shared Function ChangeClipboardChain(ByVal hWnd As IntPtr, ByVal hWndNext As IntPtr) As _
       <MarshalAs(UnmanagedType.Bool)> Boolean
   End Function

   <DllImport("user32")> _
   Private Shared Function SendMessage(ByVal hWnd As IntPtr, ByVal msg As Integer, ByVal wParam As IntPtr, _
       ByVal lParam As IntPtr) As IntPtr
   End Function

   Sub New()
       InitializeComponent()
       mNextClipBoardViewerHWnd = SetClipboardViewer(Me.Handle)
       AddHandler Me.OnClipboardChanged, AddressOf ClipBoardChanged
   End Sub

   Protected Overrides Sub WndProc(ByRef m As Message)
       Select Case m.Msg
           Case WM_DRAWCLIPBOARD
               RaiseEvent OnClipboardChanged()
               SendMessage(mNextClipBoardViewerHWnd, m.Msg, m.WParam, m.LParam)

           Case WM_CHANGECBCHAIN
               If m.WParam.Equals(mNextClipBoardViewerHWnd) Then
                   mNextClipBoardViewerHWnd = m.LParam
               Else
                   SendMessage(mNextClipBoardViewerHWnd, m.Msg, m.WParam, m.LParam)
               End If
       End Select
       MyBase.WndProc(m)
   End Sub

   Private Sub ClipBoardChanged()
       Dim data As IDataObject = Clipboard.GetDataObject()
       If data.GetDataPresent(GetType(Bitmap)) Then
           Me.BackgroundImage = DirectCast(data.GetData(GetType(Bitmap)), Bitmap)
       End If
   End Sub

   Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As FormClosingEventArgs) Handles Me.FormClosing
       ChangeClipboardChain(Me.Handle, mNextClipBoardViewerHWnd)
   End Sub

End Class

To use: start a few instances of the program. Copy an image into the clipboard - the backgrounds of the forms should change. Then close one of the forms and change the image in the clipboard - all the backgrounds should change.

Read CID and CSD C# implementation.

2008-11-30T15:54:00.000Z

Ok, here goes. It's pretty huge, so I'll just post the important bits and post a download link to the source at the bottom. I've not yet started on getting overlap to work. YOU HAVE TO SET THE BUILD TARGET TO x86. (if you have an express edition then you'll need to expose the configuration manager first - its in the settings somewhere - "show advanced build options" or something).

(Remember this is Windows XP/Vista, Admin privileges required, build target must be x86, SD card must be attached via an SD reader connected directly to the PCI host - no USB reader...)

First up...

ENUMS - Boring they are in the header files in the WDK

// SD_COMMAND_CLASS
public enum SdCommandClass : uint
{
    Standard,                       // SDCC_STANDARD
    AppCmd                          // SDCC_APP_CMD
};

// SD_TRANSFER_DIRECTION
public enum SdTransferDirection : uint
{
    Unspecified,                    // SDTD_UNSPECIFIED
    Read,                           // SDTD_READ
    Write                           // SDTD_WRITE
};

// SD_TRANSFER_TYPE
public enum SdTransferType : uint
{
    Unspecified,                    // SDTT_UNSPECIFIED
    CmdOnly,                        // SDTT_CMD_ONLY
    SingleBlock,                    // SDTT_SINGLE_BLOCK
    MultiBlock,                     // SDTT_MULTI_BLOCK
    MultiBlockNoCmd12               // SDTT_MULTI_BLOCK_NO_CMD12
};

// SD_RESPONSE_TYPE
public enum SdResponseType : uint
{
    Unspecified,                    // SDRT_UNSPECIFIED
    None,                           // SDRT_NONE
    R1,                             // SDRT_1
    R1b,                            // SDRT_1B
    R2,                             // SDRT_2
    R3,                             // SDRT_3
    R4,                             // SDRT_4
    R5,                             // SDRT_5
    R5b,                            // SDRT_5B
    R6                              // SDRT_6
};

// SFFDISK_DCMD
public enum SffdiskDcmd : uint
{
    GetVersion,                     // SFFDISK_DC_GET_VERSION
    LockChannel,                    // SFFDISK_DC_LOCK_CHANNEL
    UnlockChannel,                  // SFFDISK_DC_UNLOCK_CHANNEL
    DeviceCommand                   // SFFDISK_DC_DEVICE_COMMAND
};

public enum IoCtlCode : uint
{
    SffdiskQueryDeviceProtocol = 0x71E80,       // IOCTL_SFFDISK_QUERY_DEVICE_PROTOCOL   
    SffdiskDeviceCommand = 0x79E84,             // IOCTL_SFFDISK_DEVICE_COMMAND   
    VolumeGetVolumeDiskExtents = 0x560000       // IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS
};

Native Methods - There are plenty of overrides of DeviceIOControl. The last one that takes byte[] sends the sd command. Note the use of SafeHandles instead of IntPtr.

[DllImport("kernel32", CharSet = CharSet.Unicode, SetLastError = true)]
public extern static SafeFileHandle CreateFile(String fileName, AccessRights desiredAccess, ShareModes shareMode, IntPtr securityAttributes, CreationDisposition creationDisposition, int flagsAndAttributes, IntPtr hTemplateFile);

// overload used for querydeviceprotocol
[DllImport("kernel32", SetLastError = true)]
public extern static bool DeviceIoControl(SafeFileHandle hVol, IoCtlCode controlCode, IntPtr inBuffer, int inBufferSize, ref SffdiskQueryDeviceProtocolData outBuffer, int outBufferSize, out int bytesReturned, IntPtr overlapped);

// overload used for getting the disk extents
[DllImport("kernel32", SetLastError = true)]
public extern static bool DeviceIoControl(SafeFileHandle hVol, IoCtlCode controlCode, IntPtr inBuffer, int inBufferSize, out DiskExtents outBuffer, int outBufferSize, out int bytesReturned, IntPtr overlapped);

// overload used for getting more than 1 diskextent
[DllImport("kernel32", SetLastError = true)]
public extern static bool DeviceIoControl(SafeFileHandle hVol, IoCtlCode controlCode, IntPtr inBuffer,int inBufferSize, IntPtr outBuffer, int outBufferSize, out int bytesReturned, IntPtr overlapped);

// Overload for the CID
[DllImport("kernel32", SetLastError = true)]
public extern static bool DeviceIoControl(SafeFileHandle hVol, IoCtlCode controlCode, Byte[] inBuffer, int inBufferSize, Byte[] outBuffer, int outBufferSize, out int bytesReturned, IntPtr ovelapped);

The Structures - No fancy marshaling required. Again, see the WDK header files.

// SDCMD_DESCRIPTOR
[StructLayout(LayoutKind.Sequential)]
struct SdCmdDescriptor
{
    public Byte CommandCode;
    public SdCommandClass CmdClass;
    public SdTransferDirection TransferDirection;
    public SdTransferType TransferType;
    public SdResponseType ResponseType;
    public int GetSize()
    {
        return Marshal.SizeOf(this);
    }
}

// SFFDISK_DEVICE_COMMAND_DATA
[StructLayout(LayoutKind.Sequential)]
struct SffdiskDeviceCommandData
{
    public ushort Size;                     // 0
    public ushort Reserved;                 // 2
    public SffdiskDcmd Command;             // 4
    public ushort ProtocolArgumentSize;     // 8
    public uint DeviceDataBufferSize;       // 12
    public uint Information;                // 16   *ULONG_PTR*, Data[] Follows.
    public void Init()
    {
        this.Size = (ushort)Marshal.SizeOf(this);
    }
}

// SFFDISK_QUERY_DEVICE_PROTOCOL_DATA
[StructLayout(LayoutKind.Sequential)]
struct SffdiskQueryDeviceProtocolData
{
    public ushort Size;
    public ushort Reserved;
    public Guid ProtocolGuid;
    public void Init()
    {
        this.Size = (ushort)Marshal.SizeOf(this);
    }
}

The class that makes the call - could do with more tidying up. CID and CSD are classes with lots of properties, the constructor takes the byte array returned by the deviceIOControl call and fills in the properties. They probably have mistakes too. See the linked code.

using Microsoft.Win32.SafeHandles;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;

namespace JDMcF.SDCard
{
    // This class might get some information about an SDCard.
    // Does not work with USB SD Card Readers.
    // Does not work with some SD Bus Host Drivers.
    // Administrator privileges required.
    // I don't know if the IOCTLs work with mobile devices.
    // I don't know if I'm translating the bytes from the CID correctly.
    public class SDCard
    {
        // GUID_SFF_PROTOCOL_SD
        private static readonly Guid GuidSffProtocolSd = new Guid("AD7536A8-D055-4C40-AA4D-96312DDB6B38");

        private CID cid;
        public CID CID { get { return cid; } }

        private CSD csd;
        public CSD CSD { get { return csd; } }

        private DriveInfo driveInfo;
        public DriveInfo DriveInfo { get { return driveInfo; } }

        private string physicalDrivePath;
        public string PhysicalDrivePath { get { return physicalDrivePath; } }

        private SDCard(string physicalDrivePath, DriveInfo driveInfo)
        {
            // At first only these are initialised. It takes a second or so to
            // read the CID so we so
            // it on another thread and raise an event once done.
            this.physicalDrivePath = physicalDrivePath;
            this.driveInfo = driveInfo;
        }

        public static List<SDCard> GetSDCards()
        {
            List<SDCard> cards = new List<SDCard>();
            // There are probably ways to mount the card elsewhere,
            // so it might miss those...
            foreach (DriveInfo di in System.IO.DriveInfo.GetDrives())
            {
                // Are all SD Cards Removable? I don't know!
                if (di.DriveType == DriveType.Removable)
                {
                    // We are enumerating volumes. Volumes can span physical
                    // disks. Work out how many physical disks are involved
                    // with each volume. (seems unlikely, but I just figured
                    // out how to do this so what the heck)...
                    List<string> physicalPaths =
                        VolumeInfo.GetPhysicalDriveStrings(di);
                    foreach (string physicalPath in physicalPaths)
                    {
                        if (IsSD(physicalPath))
                        {
                            cards.Add(new SDCard(physicalPath, di));
                        }
                    }
                }
            }
            return cards;
        }

        // Send IOCTL_SFFDISK_QUERY_DEVICE_PROTOCOL to see if the handle
        // belongs to an SD Card.
        private static bool IsSD(string physicalPath)
        {
            SafeFileHandle hVol = null;
            try
            {
                hVol = NativeMethods.CreateFile(physicalPath, AccessRights.GenericRead, ShareModes.FileShareRead  ShareModes.FileShareWrite,
IntPtr.Zero, CreationDisposition.OpenExisting, 0, IntPtr.Zero);
                if (hVol.IsInvalid)
                {
                    throw new Win32Exception("Couldn't CreateFile for " +
                                             physicalPath);
                SffdiskQueryDeviceProtocolData queryData1 =
                    new SffdiskQueryDeviceProtocolData();
                queryData1.Init();
                int bytesReturned;
                bool result = NativeMethods.DeviceIoControl(hVol, IoCtlCode.SffdiskQueryDeviceProtocol, IntPtr.Zero, 0, ref queryData1, queryData1.Size, out bytesReturned, IntPtr.Zero);
                return queryData1.ProtocolGuid.Equals(GuidSffProtocolSd);
            }
            finally
            {
                if (hVol != null)
                {
                    if (!hVol.IsInvalid)
                    {
                        hVol.Close();
                    }
                    hVol.Dispose();
                }
            }
        }

        public void RefreshData()
        {
            GetRegister(Register.CID);
            GetRegister(Register.CSD);
        }

        // Send the command in the array. On return the array will have any
        // response.
        private void SendCommand(byte[] command)
        {
            SafeFileHandle hVol = null;
            try
            {
                hVol = NativeMethods.CreateFile(PhysicalDrivePath, AccessRights.GenericRead  AccessRights.GenericWrite, ShareModes.FileShareRead  ShareModes.FileShareWrite, IntPtr.Zero, CreationDisposition.OpenExisting, 0, IntPtr.Zero);
                int bytesReturned;
                bool result = NativeMethods.DeviceIoControl(hVol, IoCtlCode.SffdiskDeviceCommand, command, command.Length, command, command.Length, out bytesReturned, IntPtr.Zero);
                if (!result) throw new Win32Exception();
            }
            finally
            {
                if (hVol != null)
                {
                    if (!hVol.IsInvalid)
                    {
                        hVol.Close();
                    }
                    hVol.Dispose();
                }
            }
        }

        // Get the CID or CSD. They are almost identical commands...
        private void GetRegister(Register register)
        {
            byte[] command = null;
            SffdiskDeviceCommandData commandData = new SffdiskDeviceCommandData();
            SdCmdDescriptor commandDescriptor = new SdCmdDescriptor();
            commandData.Init();
            commandData.Command = SffdiskDcmd.DeviceCommand;
            commandData.ProtocolArgumentSize = (ushort)commandDescriptor.GetSize();
            commandData.DeviceDataBufferSize = 16;
            commandDescriptor.CommandCode = (byte)register;   // <--- Not what the documentation indicates!
            commandDescriptor.CmdClass = SdCommandClass.Standard;
            commandDescriptor.TransferDirection = SdTransferDirection.Read;
            commandDescriptor.TransferType = SdTransferType.CmdOnly;
            commandDescriptor.ResponseType = SdResponseType.R2;

            // Now get the structs into the byte[]
            command = new byte[commandData.Size + commandData.ProtocolArgumentSize + commandData.DeviceDataBufferSize];
            IntPtr hBuf = Marshal.AllocHGlobal(command.Length);
            Marshal.StructureToPtr(commandData, hBuf, true);
            IntPtr descriptorOffset = new IntPtr(hBuf.ToInt32() + commandData.Size);
            Marshal.StructureToPtr(commandDescriptor, descriptorOffset, true);
            Marshal.Copy(hBuf, command, 0, command.Length);
            Marshal.FreeHGlobal(hBuf);

            SendCommand(command);
            // Strip out the return bytes that live at the end of the command byte array.
            byte[] regBytes = new byte[16];
            Buffer.BlockCopy(command, command.Length - 16, regBytes, 0, 16);

            if (register == Register.CID)
            {
                cid = new CID(regBytes);
            }
            else
            {
                csd = new CSD(regBytes);
            }
        }
    }
}

Formatting is awful...

Howto: Get the physical drive string //./PhysicalDriveX from a path

2008-11-27T15:58:00.000Z

There are lots of strings that you can feed CreateFile, if we are looking at volumes and drives then they include:

The Unique Volume Name:

\\?\Volume{013eeefb-9b12-11dd-bee5-806e6f6e6963}\

You can list those at the command prompt with: "mountvol".

The mount point:

\\.\C:

If you really want to list them at the command line, then "fsutil fsinfo drives" will do the trick.

The physical drive string (or whatever it is called)

\\.\PhysicalDrive0

command: "wmic diskdrive get name,size,model"

But, how can we get all of the physical drive strings available? Well, the hint is in the CreateFile documentation.

To obtain the physical drive for a volume, open a handle to the volume and call the DeviceIoControl function with IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS. This control code returns the disk number of offset for each of the volume's extents; a volume can span disks.

In .Net then, start by enumerating all the drives, and create strings like the mount points above "\\.\X:". Use this with CreateFile to get a handle to the volume. Then call DeviceIOControl with IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS.

The Class that does the hard work:

Project type - vb.net class library (2005 or 2008) - name JdMcF.VolumeInfo:

Option Strict On
Option Explicit On

Imports Microsoft.Win32.SafeHandles
Imports System.IO
Imports System.Runtime.InteropServices
Imports System.ComponentModel

Public Class VolumeInfo

   Private Const GenericRead As Integer = &H80000000
   Private Const FileShareRead As Integer = 1
   Private Const Filesharewrite As Integer = 2
   Private Const OpenExisting As Integer = 3
   Private Const IoctlVolumeGetVolumeDiskExtents As Integer = &H560000
   Private Const IncorrectFunction As Integer = 1
   Private Const ErrorInsufficientBuffer As Integer = 122

   Private Class NativeMethods
       <DllImport("kernel32", CharSet:=CharSet.Unicode, SetLastError:=True)> _
       Public Shared Function CreateFile( _
           ByVal fileName As String, _
           ByVal desiredAccess As Integer, _
           ByVal shareMode As Integer, _
           ByVal securityAttributes As IntPtr, _
           ByVal creationDisposition As Integer, _
           ByVal flagsAndAttributes As Integer, _
           ByVal hTemplateFile As IntPtr) As SafeFileHandle
       End Function

       <DllImport("kernel32", SetLastError:=True)> _
       Public Shared Function DeviceIoControl( _
           ByVal hVol As SafeFileHandle, _
           ByVal controlCode As Integer, _
           ByVal inBuffer As IntPtr, _
           ByVal inBufferSize As Integer, _
           ByRef outBuffer As DiskExtents, _
           ByVal outBufferSize As Integer, _
           ByRef bytesReturned As Integer, _
           ByVal overlapped As IntPtr) As <MarshalAs(UnmanagedType.Bool)> Boolean
       End Function

       <DllImport("kernel32", SetLastError:=True)> _
       Public Shared Function DeviceIoControl( _
           ByVal hVol As SafeFileHandle, _
           ByVal controlCode As Integer, _
           ByVal inBuffer As IntPtr, _
           ByVal inBufferSize As Integer, _
           ByVal outBuffer As IntPtr, _
           ByVal outBufferSize As Integer, _
           ByRef bytesReturned As Integer, _
           ByVal overlapped As IntPtr) As <MarshalAs(UnmanagedType.Bool)> Boolean
       End Function
   End Class

   ' DISK_EXTENT in the msdn.
   <StructLayout(LayoutKind.Sequential)> _
   Private Structure DiskExtent
       Public DiskNumber As Integer
       Public StartingOffset As Long
       Public ExtentLength As Long
   End Structure

   ' DISK_EXTENTS
   <StructLayout(LayoutKind.Sequential)> _
   Private Structure DiskExtents
       Public numberOfExtents As Integer
       Public first As DiskExtent ' We can't marhsal an array if we don't know its size.
   End Structure

   ' A Volume could be on many physical drives.
   ' Returns a list of string containing each physical drive the volume uses.
   ' For CD Drives with no disc in it will return an empty list.
   Public Shared Function GetPhysicalDriveStrings(ByVal driveInfo As DriveInfo) As List(Of String)
       Dim sfh As SafeFileHandle = Nothing
       Dim physicalDrives As New List(Of String)(1)
       Dim path As String = "\\.\" & driveInfo.RootDirectory.ToString.TrimEnd("\"c)
       Try
           sfh = NativeMethods.CreateFile(path, GenericRead, FileShareRead Or Filesharewrite, IntPtr.Zero, _
                                                          OpenExisting, 0, IntPtr.Zero)
           Dim bytesReturned As Integer
           Dim de1 As DiskExtents = Nothing
           Dim numDiskExtents As Integer = 0
           Dim result As Boolean = NativeMethods.DeviceIoControl(sfh, IoctlVolumeGetVolumeDiskExtents, IntPtr.Zero, _
                                                                 0, de1, Marshal.SizeOf(de1), bytesReturned, IntPtr.Zero)
           If result = True Then
               ' there was only one disk extent. So the volume lies on 1 physical drive.
               physicalDrives.Add("\\.\PhysicalDrive" & de1.first.DiskNumber.ToString)
               Return physicalDrives
           End If
           If Marshal.GetLastWin32Error = IncorrectFunction Then
               ' The drive is removable and removed, like a CDRom with nothing in it.
               Return physicalDrives
           End If
           If Marshal.GetLastWin32Error <> ErrorInsufficientBuffer Then
               Throw New Win32Exception
           End If           
           ' Houston, we have a spanner. The volume is on multiple disks.
           ' Untested...
           ' We need a blob of memory for the DISK_EXTENTS structure, and all the DISK_EXTENTS
           Dim blobSize As Integer = Marshal.SizeOf(GetType(DiskExtents)) + _
                                     (de1.numberOfExtents - 1) * Marshal.SizeOf(GetType(DiskExtent))
           Dim pBlob As IntPtr = Marshal.AllocHGlobal(blobSize)
           result = NativeMethods.DeviceIoControl(sfh, IoctlVolumeGetVolumeDiskExtents, IntPtr.Zero, 0, pBlob, _
                                                  blobSize, bytesReturned, IntPtr.Zero)
           If result = False Then Throw New Win32Exception
           ' Read them out one at a time.
           Dim pNext As New IntPtr(pBlob.ToInt32 + 4) ' is this always ok on 64 bit OSes? ToInt64?
           For i As Integer = 0 To de1.numberOfExtents - 1
               Dim diskExtentN As DiskExtent = DirectCast(Marshal.PtrToStructure(pNext, GetType(DiskExtent)), DiskExtent)
               physicalDrives.Add("\\.\PhysicalDrive" & diskExtentN.DiskNumber.ToString)
               pNext = New IntPtr(pNext.ToInt32 + Marshal.SizeOf(GetType(DiskExtent)))
           Next
           Return physicalDrives
       Finally
           If sfh IsNot Nothing Then
               If sfh.IsInvalid = False Then
                   sfh.Close()
               End If
               sfh.Dispose()
           End If
       End Try
   End Function

End Class

The Test project:

Project type: vb.net windows forms app (2005 or 2008) name: whatever.

Option Strict On
Option Explicit On
Option Infer Off

Imports JDMcF.VolumeInfo
Imports System.IO
Imports System.Text

Public Class Form1

   Private lv1 As New ListView

   Sub New()

       ' This call is required by the Windows Form Designer.
       InitializeComponent()

       ' Add any initialization after the InitializeComponent() call.
       With lv1
           .View = View.Details
           .Columns.Add("Root", 100, HorizontalAlignment.Left)
           .Columns.Add("Physical Drive String", 200, HorizontalAlignment.Left)
           .Dock = DockStyle.Fill
       End With
       Me.Controls.Add(lv1)       
   End Sub

   Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
       For Each di As DriveInfo In DriveInfo.GetDrives
           Dim drivesList As List(Of String) = VolumeInfo.GetPhysicalDriveStrings(di)

           Dim drives As New StringBuilder
           If drivesList.Count > 0 Then
               For Each s As String In drivesList
                   drives.Append(s)
                   drives.Append(", ")
               Next
               drives.Remove(drives.Length - 2, 2)
           Else
               drives.Append("n/a")
           End If
           Dim lvi As New ListViewItem(di.RootDirectory.ToString)
           lvi.SubItems.Add(drives.ToString)
           lv1.Items.Add(lvi)
       Next
   End Sub

End Class

Linky to code:

SD Card - Read CID/Serial number - Musings

2008-11-26T16:10:00.000Z

Well I discovered that my .Net app does actually work on 32 bit operating systems too. Assuming I'm reading the data correctly, I can read CIDs in XP SP2, on an old Asus W5 laptop. It also has an integral card reader. BUT: it didn't work at first. DeviceIOControl returned "Invalid Function" (Win32 Error code 1). I went in to device manager and changed the driver over:

TO:

So, It looks like the driver plays an important role too...

So to read the CID, so far I've found:

1) You can't get it if the reader is a USB device. 2) You can't get it if the driver doesn't like the DeviceIOControl call.

CreateFile path for the Volume:

There are 2 choices mentioned on forums/in documentation. "//./X:" or "//./PhysicalDriveX". There's another one with a guid too.

I've been using "//./X:" as it worked. Maybe using the other path to get the handle will make a difference on the machine where I can't get it to work:

C:\Users\SEP>wmic diskdrive get name,size,model Model Name Size FUJITSU MHW2160BJ G2 \\.\PHYSICALDRIVE0 160039272960 SD Memory Card \\.\PHYSICALDRIVE1 8225280

Edit: I'm now on about version 5 of my program and I'm using C#! So, I've moved from C++/CLI -> VB.Net -> C#... It now works on the machine I mentioned above, and I'm using the physicaldrive string. I'm trying to get Overlapped to work on x64 and x32, it seems there are some problems with NativeOverlapped. This will allow the call to read the CID and CSD to run on another thread, and the user to be notified when the results come back. (Reading the CID takes a noticable amount of time.) It requires a pointer, hence the move to C#.

C++ Interop example. FlashWindowEx

2008-11-16T16:01:00.000Z

I've been using C++ occasionally instead of P/Invoke. I'm not a c++ programmer.

Here's how to use c++ express 2008 and vb.net 2008 together to call a platform method.

First start C++.
File->New->Project-> Project Type = CLR and use the Class Library template, set the project name to Flasher.
Insert some code into Stdafx.h so that it looks like this:

#pragma once #define STRICT #define WIN32_LEAN_AND_MEAN #include <windows.h> using namespace System;

You can see that we have included windows.h, which will give us access to many standard c++ types, such as BOOL. Windows.h is huge, so we set lean and mean too, which strips some infrequently used items -- they won't be included. #define STRICT is similar to Option Strict in vb.net. It stops you being lazy!
Next we need to declare a class and a static method (which is a vb.net Shared method):

// Flasher.h

#pragma once using namespace System; namespace Flasher { public ref class Flasher { public: static void Flash(IntPtr); }; }
Now we add method code in the cpp file:

// This is the main DLL file.

#include "stdafx.h" #include "Flasher.h" namespace Flasher { void Flasher::Flash(IntPtr hWndManaged) { FLASHWINFO info; ZeroMemory(&info, sizeof(FLASHWINFO)); info.uCount = 5; info.dwFlags = FLASHW_CAPTION; info.dwTimeout = 0; info.hwnd = (HWND) hWndManaged.ToPointer(); info.cbSize = sizeof(info); BOOL result = FlashWindowEx(&info); }
}

First we include those header files, so we get all of the methods and types declared in windows.h, and our own Flash method. Next we have the Flash method. To call FlashWindowEx you send a FLASHWINFO structure. If we were going to P/Invoke this, then we would need to declare our own versions of FlashWindowEx and FLASHWINFO. Here we don't have to, as we have the header files included. At the same time, this is a .Net dll, so our Flash method will be usable from VB.Net. After declaring a FLASHWINFO variable, we zero the memory. This is because C++ doesn't do it for us, we could get all sorts of junk in the new structure's fields if we don't do this. The & in &info is telling ZeroMemory the address where the info structure lives. We tell it to flash 5 times. We tell it to flash the caption. We tell it to flash at the default rate (= the systems cursor blink rate) by setting timeout to 0. Next we need to convert the managed IntPtr that is the windows Handle, into the unmanaged HWND type. This involves the ToPointer method, and a cast. Finally we set the structure size and send it off.
Does it build?
No it doesn't. Unresolved token, and unresolved external symbol. There is a linker error, look at the msdn page for FlashWindowEx: Library: Use User32.lib This means that we need to link against User32.lib. We aren't, so we get the error. Right click the project name "Flasher" in the solution explorer. Click properties. Look at: Configuration Properties/Linker/Input/Additional Dependencies Make sure the additional dependencies line is selected and click the ellipsis (...). A quick glance makes you think user32 is linked, but actually the list is a list of thinks that can be inherited, but we have $(NoInherit) set. Add user32.lib to the listbox. Once done, click Ok, and you should see: Additional Dependencies: user32.lib $(NOINHERIT)
Does it build?
No it doesn't. This time it's my antivirus software keeping the file open, causing a file access error: "mt.exe : general error c101008d: Failed to write the updated manifest to the resource of file" One that's sorted, it builds. Add an antivirus exception for mt.exe. For me it lives here: (C:\Program Files\Microsoft SDKs\Windows\v6.0A\bin)
Start a new VB.Net project. Add a button. Click Project->Add Reference, select the browse tab, navigate to the C++ dll that was built and add that.
Add the following to the button click code:

Flasher.Flasher.Flash(Me.Handle)
Does it build? For me - yes!
Does it run? For me - no! I'm using Vista 64, and get: "Could not load file or assembly 'Flasher, Version=1.0.3245.7081, Culture=neutral, PublicKeyToken=null' or one of its dependencies. An attempt was made to load a program with an incorrect format." This is fixed by setting the Target for the VB.Net program to x86, it was on AnyCPU, the dll is win32! In vb express you might need to do: Tools->Options->Projects and Solutions->General->Show Advanced Build Configurations then, you will need: Build->Configuration Manager->Active Solution Platform -- select <New> and x86
It finally works.

For a simple win32 api call this is too much work. It might be worth it for performance if you are calling something a lot. If you have a complicated api, then it pays off as you don't have to make managed versions of everything. If the method is in a static library then this is a good technique.

Read secure digital (SD) card serial number from the CID

2008-11-15T16:14:00.000Z

(Quick link to an executable, this might read the serial number on Windows XP/Vista/32/64 when you are not using a USB card reader (so when you have the card in a slot on the side of a laptop it should work - though it depends on the driver!)). Requires .Net Framework 3.5.

I got an email about a post from ages ago on the msdn forums about reading the serial number from an SD Card. People want to do this as the number is factory stamped and unchangeable, so it could be used to protect programs from being copied. Distribute your program on an SD Card, have it check the serial, and have it fail if the number doesn't match a hard-coded version. Maybe there's more to it than that. But anyway the thread went along the lines of:

1) I want to read the serial 2) Someone suggested: Well use DeviceIOControl to send IOCTL_DISK_GET_STORAGEID to the drive.

At the time I'd just been playing with DeviceIOControl, and had spent ages working out how to use it from .Net. There weren't any useful examples that I could find. I was working at trying to make a CD Burner, using COM Interop to talk to IMAPI on XP (before IMAPI2). I'd learnt about DeviceIOControl, and how it can be used to send messages straight to a device. I used it to find out things that IMAPI couldn't tell you - like the exact media in the drive, and whether the drive was ready. I eventually got a vb.net program that could burn MP3s to CD. I never quite finished it though. I wasn't sure how to deal with all the possible errors during burning - there were so many!

I quickly wrote some code that demonstrated sending the message. I didn't know if the number was really the hardware stamped serial or whether it was just something windows dreamt up (like the volume serial you get with dir c:\).

I was asked again this week about this, and pointed in the direction of the concise SD specification (you can only see the big one if you pay $$$$, as it isn't an open standard). It's call the simplified version of the physical layer spec. This describes various commands that can be sent. Command 10 returns the CID. The CID is the bit we are interested in, the Card IDentification register:

Name	Field	Width	CID-slice
Manufacturer ID	MID	8	[127:120]
OEM/Application ID	OID	16	[119:104]
Product Name	PNM	40	[103:64]
Product Revision	PRV	8	[63:56]
Product Serial Number	PSN	32	[55:24]
reserved	--	4	[23:20]
Manufacturing Date	MDT	12	[19:8]
CRC7 Checksum	CRC	7	[7:1]
not used, always 1	--	1	[0:0]

There we have 128 bits used to identify the device. I was asked if the number that my earlier program grabbed was this number from the CID. I don't know...(edit - NO it isn't the same. IOCTL_DISK_GET_STORAGEID is useless - it gets a serial that Windows invents when it formats a volume.)

I decided to try and get this CID number out, and I've managed to, but there are provisos. My program (VB.Net) currently works only on Vista 64. Weirdly it only works when compiled for the x86 platform (the build target in visual studio). When I tried it on Vista 32 I got invalid handle errors. Sheesh. The other biggy is that it only works when the SD Card is plugged into a reader that is attached directly to the pci bus. If USB is involved in the chain, then the DeviceIOControl messages go to the USB host controller, and it doesn't understand them. It works on my laptop's reader, but not on a fan controller/card reading gadget plugged in to my desktop as its card reader is attached via a USB header on the mobo.

Here are some pics of the CIDs. They came out reversed, and the endianness of the serial number and manufacturer date were unhelpful. In the pics below, the 16 bytes are the ones I got in my buffer, but reversed order. They tally quite well with the above table. But, the leftmost byte (0 in each case) shouldn't be there, and we are missing the CRC and final bit. So it goes - Unspecified byte, MID, OID, OID, PNM, PNM, PNM, PNM, PNM, PRV, PSN, reserved+MDT, MDT. And the CRC is missing.

I bought the two Crucial 4GB cards at the same time, note the serial numbers are adrift by 2 - a good indication I'm not getting gobbledegook. The Manufacture date is mm/yyyy. Also the numbers tally with the hardware IDs found in Windows Device Manager, which are described in the DDK, er WDK rather. Which you can get for free now. I bought the Veho card two weeks ago, looks like it was made just last month. It also looks like Vehos are made by Corsair - or maybe they are both made by some other company. Crucial don't fill in the product name or version, all the bytes were 0.

The bit where is says "This is an SD card", is because it also checks if the drive selected in the combobox is an SD card before attempting to get data.

So, how's it done? Well, you send an IOCTL specifying an SD Command with DeviceIOControl. Again it's in the WDK. These are just user mode calls, so we aren't in the realms of writing a driver. The main difficulties were trying to decipher the documentation, which appears to be plain wrong in places. This lead to many many errors being returned by DeviceIOControl. Eventually I managed to send off command 0 without any complaint whatsoever, and figured I must be doing something right. I was using C++ code from elsewhere in the msdn forums and a bit of C++ Interop. I then got something back from cmd 10. I then went and did it in VB.Net instead as all this C++ was driving me mad. I can read it, but programming in it is a very laborious process for me.

I used IOCTL_SFFDISK_QUERY_DEVICE_PROTOCOL to check if a mount point was an SD card. Then IOCTL_SFFDISK_DEVICE_COMMAND to send cmd10. DeviceIOControl just takes the IOCTL code and a blob of memory - in .Net I used a byte array. The byte array contains a SFFDISK_DEVICE_COMMAND_DATA structure first, then the SDCMD_DESCRIPTOR. Both of these structures were 20 bytes big on x64 vista when using c++, so I made sure they were that size in .Net too. The Cmd field of SDCMD_DESCRIPTOR is very nasty. The documentation says to fill it with a value from the SD_COMMAND_CODE data type and lists two "allowed values". Well, both of those values give errors. Instead you should set the sd command code - i.e. 10 for command 10, 0 for command 0!!!!! After that structure I sent 16 bytes to receive the CID. And unfortunately I get 15 bytes of CID with a 00 in front and no CRC. Maybe I have some alignment problems with the structures. It might explain why my code isn't porting too.

I'll iron out the bugs and try and get it running on my dilapidated axim 50v too with the compact framework. I'm currently attempting to flash the rom on it to something newer. I nearly binned it last week in a grand tidy up. I'll have to download the academic version of Visual Studio, which is Pro, to do the windows mobile stuff. I've only got Standard (which was a MS freebie from the launch). Code to follow. (note there are other, newer, posts on this on the blog, and some other code)

Dell Laptop - delivery tracking saying "call lock out"

2008-11-13T16:04:00.000Z

"This means your order is now ready for delivery and you will receive a call shortly to advise you of delivery date and options available for your order."

That is an explanation of the strange "call lock out" stage you see when you use order tracking from Syncreon (Walsh Western merged into this company) to see where your new dell gizmo is. I emailed them to find out what it meant. Whilst waiting for a reply, I got the automated call asking me to confirm the delivery time, and as soon as I hung up, a new bit had appeared on the tracking page showing the delivery date/time I arranged...

Open University M366 - exam post mortem

2008-10-20T17:37:00.000+01:00

The M366 results came in and I wrote a long post about it - but it disappeared. Great.

M366 is an Open University course, level 3, 30 points (should be more!) entitled "Natural and Artificial Intelligence". I managed to get a distinction, with something like 96 in the continual assessment and 92 in the exam. It was hard work, so I'm glad the paper had no nasty surprises.

So, for peeps thinking "Should I do M366"? Well - it depends. Are you interested and doing it for fun rather than aiming for a particular qualification? If so then yeah - have a go. Are you aiming for a degree and need a high mark to get the grade you want? If so then M366 might not be the best plan, the grade breakdown for our presentation (the first presentation) was:

- so if you need a distinction there might be easier options. M366 is a lot more work than the other L3 I've taken so far (the concurrency one). M366 is multidisciplinary - you have a bit of maths (quite light), logic, computer science, programming, history, philosophy of AI. Some people come in to the course wanting to read about themes of consciousness, and philosophy. Others come in wanting to learn algorithms to help with their programs. Two different camps, both find parts of the course unfamiliar and difficult. The dropout rate was high.

If you do take M366 then...

Read ahead early on, it doesn't matter if you fail to grasp 50% of it, just read it all early on to get the gist of the underlying themes.
Allot more time to this than you usually do. I read the units twice before tackling the TMA, and again during the TMA.
Don't go nuts. I did, I spent ages perfecting my TMAs, going much further than required with the coding section. We had a TMA question that asked for a heuristic for a search and I knew what they expected within a couple of minutes, but I didn't like it as a solution and spent days making a better version. It wasn't really worth the time. My heuristic was faster and found shorter solutions though - much better (their one overestimated - a cardinal sin!).
Code some of it in <Insert you native programming language here>. I did some C# and VB.Net programs implementing search and genetic algorithms. It improved my understanding.
Unit 6 is critical for the exam. There is a compulsory question. The subject matter is not maths/programming and so it needed a lot of work. Write notes on stuff like the Chinese Room. Write an essay on the notes. Condense the essay down to something much shorter. Re-Write it the next day to reinforce your understanding. Do this for all the other junk in Unit 6. It will take a few days, but you will then be able to do the exam question easily.
Netlogo. Many folk detested this. Some were not programmers, and so they were dunked in at the deep end. To those people, don't panic. You needn't write any code - if you can explain in words how it should work then you'll get marks. Once you work out that, you might be able to takle the coding. Some were programmers, and they hated the language. NetLogo is from a different branch of the programming language tree to most of the common programming languages - C, Java, VB, LoLCode, etc. You'll see it is a LISP-a-like. It is worth finding a tutorial on LISP and having a go at the basic syntax (or SICP if you are a glutton for punishment). I liked NetLogo. Write some simple programs - get used to lists of things and making your own data structures from lists.
Rote learn. Create some lists for the "compare and contrast" type questions and rote learn them...
Don't leave TMAs until the last minute. You can't breeze through these ones as the Units are huge and complicated. I learnt miles more doing the TMAs than I did studying the units before doing the TMAs.
Leave at least a fortnight of late nights for revision.
Don't whinge if it is too hard. Take a look at the MIT courses...

Open University - M362/M256 exams over

2008-10-15T17:18:00.000+01:00

Exams finally over. I was a doofus and thought they were the coming Friday and Monday. I ended up with 4 nights for M362 and a weekend for M256 when I realised my mistake. I've no idea why, but I had the wrong date down on a bit of paper and I referred to the bit of paper whenever I wanted to work out how much longer I could procrastinate for.

Anyway, the both went ok in the end. I'll guess a Grade 1 pass for M256, and a borderline 1/2 for M362. It would be very nice indeed for that to be a 1, as then I can relax for my 3 remaining Level 3s. Otherwise I'll need to concentrate hard on one of them to get a Grade 1 pass - you need 60 points at Grade 1 in Level 3 courses for a first.

The past paper MCQ answers for M256, (Wednesday 17th October 2007 - M256/S) we reckoned to be:

1	2	3	4	5	6	7	8	9	10
AD	BD	DE	BE	CD	AE	BDF	CE	BC	BF
11	12	13	14	15	16	17	18	19	20
BE	CE	C	BD	ABF	BD	BE	AD	CE	C

5 - this is dumb, you read "an abstract class may have instances" and immediately think - "no way Hosé". But, in M256 parlance, they can have instances - these being instances of their concrete subclasses. Urgh. It's in the Glossary.

M362 (2008) was deemed fair by most people taking it. Some bombed and are expecting re-sits. I did Q13, which was a bold move. The paper is available now. I reckoned I would drop 5 or 6 marks on Q12, especially as I didn't like the last part one bit (security managers / RMI). So, I took Q13 - I liked the last bit on JAAS, but now I'm not so sure. I found the terms features and resources in parts a and c confusing - too vague. I guess it will be a grade 2. Widdle.

M256 (2008) was deemed unfair by most in the forum. A few people thought it went ok, I guess others are keeping quiet, not wanting to disturb the waters. The main complaints were the sheer volume of text you get for the main questions. They are pretty bulky, but most is just reference. Then folk didn't like the things you hand to copy out into your answer booklet and complete - a huge sequence diagram and a walk-through. I don't know if some people were using a ruler for their sequence diagrams. Don't, just scrawl it out. I ran out of room for mine. If your reading this with M256 approaching, then practice drawing a huge sequence diagram out on A4 - landscape, avoiding the edges (margins you can't write in). With 2 past papers available from the OU you should be in a better position to revise. I had a problem with Q23, I think there was a method missing in the protocol - so I had to make one up - a getter for something or other. I'll check when the paper comes out. I couldn't see another way of getting the information (alternative navigation of links, or cunning use of other methods), and the walk-through seemed to indicate that the thing was available without having to go via another object.

Visual studio macro to remove double spaced lines

2008-01-22T16:06:00.000Z

If you paste code into the MSDN forums straight from Visual Studio 2005, and then copy it back out and paste it in then you get double spaced lines. This is tedious as you often have to remove them to get the code to work.

To fix it, posters can use a Macro to format the code as HTML: Coding Horror Copying Visual Studio Code Snippets to the Clipboard as HTML.

If you want to strip the spaces from code you have pasted in then you can use a macro. I'll copy his ^^ instructions:

Here's how to get started with this macro

go to Tools - Macros - IDE
create a new Module named "DeDoubleSpace" under "MyMacros"
Paste code into the module
save and close the macro IDE window
go to Tools - Macros - Macro Explorer
The new macros will be under "DeDoubleSpace"; select the messy text and double click the macro.

Imports EnvDTE    
Imports System    
Imports System.Collections.Generic    
Imports System.IO    
Imports System.Text    
    
Public Module DeDoubleSpace    
    
    ' Remove double spaced lines from the selected text.    
    Public Sub SelectedText()    
        Dim textSelection1 As TextSelection = DirectCast(DTE.ActiveDocument.Selection, TextSelection)    
        Dim rawText As String = textSelection1.Text    
        Dim lines As New List(Of String)    
        Using sr As New StringReader(rawText)    
            lines = New List(Of String)    
            Do While sr.Peek > -1    
                lines.Add(sr.ReadLine())     
            Loop    
        End Using    
        If lines.Count < 3 Then Exit Sub    
        ' Find the first bit of text.    
        Dim indexOfFirstLineWithText As Integer = 0    
        Dim done As Boolean = False    
        Do    
            If lines(indexOfFirstLineWithText) <> "" Then    
                done = True    
            Else    
                indexOfFirstLineWithText += 1    
            End If    
        Loop Until done Or indexOfFirstLineWithText = lines.Count    
        ' Is the first line with text an odd or even line?    
        Dim even As Boolean = (indexOfFirstLineWithText Mod 2 = 0)    
        ' If it is an even line, then check if all odd lines are blank    
        ' and vice versa.    
        Dim allBlank As Boolean = True ' prove wrong    
        Dim index As Integer = IIf(even, 1, 0)    
        Do    
            If lines(index) <> "" Then    
                allBlank = False    
            Else    
                index += 2    
            End If    
        Loop Until Not allBlank OrElse index > lines.Count - 1    
        If allBlank = False Then Exit Sub    
        ' Create new text    
        Dim sb As New StringBuilder    
        Dim i As Integer    
        For i = IIf(even, 0, 1) To lines.Count - 3 Step 2    
            sb.AppendLine(lines(i))     
        Next    
        sb.Append(lines(i))    
        ' Alter the selection.  
        textSelection1.Delete()    
        textSelection1.Insert(sb.ToString)     
    End Sub    
    
End Module 

1	2	3	4	5	6	7	8	9	10
AD	BD	DE	BE	CD	AE	BDF	CE	BC	BF
11	12	13	14	15	16	17	18	19	20
BE	CE	C	BD	ABF	BD	BE	AD	CE	C

1	2	3	4	5	6	7	8	9	10
AD	BD	DE	BE	CD	AE	BDF	CE	BC	BF
11	12	13	14	15	16	17	18	19	20
BE	CE	C	BD	ABF	BD	BE	AD	CE	C

1	2	3	4	5	6	7	8	9	10
AD	BD	DE	BE	CD	AE	BDF	CE	BC	BF
11	12	13	14	15	16	17	18	19	20
BE	CE	C	BD	ABF	BD	BE	AD	CE	C