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Windows 3.1 Card File Format

This article was previously published under Q99340
Retired KB Content Disclaimer
This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.
This article documents the file format used by Microsoft Windowsversion 3.1 Cardfile. Please note that the Cardfile file format (.CRD)may change in future versions. All numbers in this document, includingthose in the descriptive text, should be interpreted as hexadecimalnumerals. All data pointers and count bytes in the file are unsignedbinary/hexadecimal integers in least-to-most significant format. Alltext in the file is saved in low ASCII format. In the text section ofa card's data, <CR> is always followed by <LF>.

Card File Changes in NT 3.51

The only difference in the unicode format is the signiture (DKO) and thecharacters, now 16-bits wide. The Signature can now be MGC.

The Cardfile file format is as follows:
   Byte #  Description   -------------------   0 - 2   Signature bytes--always "RRG" (52 52 47).   3 - 6   Last object's ID.   7 - 8   Number of cards in file.				
Beyond the first 9 bytes are the index lines--the information aboutthe top line of each card. The first index entry begins at byte 9 inthe file, and successive entries begin 34 bytes after the beginning ofthe last index entry (the second entry at byte 3D, the third entry atbyte 71, and so forth). The format for each index line entry is asfollows:
   Byte #  Description   -------------------   0 - 5   Null bytes, reserved for future use (should all be 00).   6 - 9   Absolute position of card data in file.   A       Flag byte (00).   B - 32  Index line text.   33      Null byte; indicates end of index entry.				
After the last index entry, each card's data is stored. Card data isin one of four general formats: graphic and text, text only, graphiconly, and blank. Blank cards consist of 4 null bytes; the other cardformats are below:
   Graphic       Text     Graphic   & Text        Only     Only   -------------------------------------------------------------------   0 - 1        0 - 1#    0 - 1         Flag Determining whether or not                                        the card contains an object.   2 - 5          *       2 - 5         Unique object ID.   6 - x          *       6 - x         The OLE object.   x+1 - x+2      *       x+1 - x+2     Character width, used for device                                        independence.   x+3 - x+4      *       x+3 - x+4     Character height.   x+5 - x+C      *       x+5 - x+C     RECT: left  - X-coordinate of the                                                      upper-left corner.                                              top   - Y-coordinate of the                                                      upper-left corner.                                              right - X-coordinate of the                                                      lower-right corner.                                              bottom- Y-coordinate of the                                                      lower-right corner.   x+D - x+E      *       x+D - x+E     Object type embedded=0, linked=1,or                                        static=2 (values may change in the                                        future).   x+F - x+10   2 - 3     x+F - x+10#   Length of text entry.   x+11 - y     4 - z         *         Text.				
   x = 6 + size in bytes of the entire OLE object (the entire size of the       object is not stored anywhere within the .CRD file). See below for       more information on the OLE object size.   y = x + 10 + length of text entry.   z = 3 + length of text entry.   # - These bytes are null if no object/text.   * - These bytes do not exist if no object/text.				
The first byte of any card's data entry is pointed to by bytes 6-9 inthe index entry. Note that no null byte is used to indicate the end ofthe card's data entry; the next card's data entry immediately followsthe last byte of the previous entry, which is null only if theprevious card has no text (null length of text entry).

OLE Object

The size of the OLE object is not stored anywhere within the .CRDfile. The OLE object could be loaded using OleLoadFromStream();however, to get passed the OLE object, the file needs to be parsed.The OLE object's format description is documented in Appendix C of the"Object Linking and Embedding Programmer's Reference" version 1.0,published by Microsoft Press, and also in the Microsoft WindowsSoftware Development Kit (SDK) "Programmer's Reference, Volume 1:Overview," Chapter 6, Object Storage Format. Below is an algorithmthat uses the OLE object's format description to parse the OLE objectin the .CRD file and pass it.

Need Five Primary Functions

   Primary Function        Description   -----------------------------------   ReadLong()            - Reads a long from the file and advances the file                           pointer.   EatBytes(NumBytes)    - Reads and discards the specified number of bytes                           from the file and advances the file pointer.   RdChkVer()            - Reads the version number and advances the file                           pointer and returns TRUE if version is 1.0. To                           check the version number, the received value                           must be converted to Hex then checked against                           0x0100.                           (See below for the algorithm of this function.)   RdChkString()         - Reads the string and checks the value to see if                           it is either METAFILEPICT, BITMAP, or DIB, then                           returns TRUE; otherwise, returns FALSE. Advances                           the file pointer too.   SkipPresentationObj() - Reads and skips the variable-length presentation                           object at the end of each object type.                           (See below for the algorithm of this function.)				

Algorithm to Skip Over the OLE Object

if (RdChkVer)                  // If the version is 1.0  Format = ReadLong();         // 1==> Linked, 2==> Embedded, 3==> Static  EatBytes(ReadLong());        // Class String  if (Format == 3)             // Static object    ReadLong();                // Width in mmhimetric.    ReadLong();                // Height in mmhimetric.    EatBytes(ReadLong());      // Presentation data size and data itself.  else                         // Embedded or linked objects.    EatBytes(ReadLong());      // Topic string.    EatBytes(ReadLong());      // Item string.    if (Format == 2)           // Embedded object.      EatBytes(ReadLong());    // Native data and its size.      SkipPresentationObj()    // Read and eat the presentation object.    else                       // Linked object.      EatBytes(ReadLong());    // Network name.      ReadLong();              // Network type and net driver version.      ReadLong();              // Link update options.      SkipPresentationObj()    // Read and eat the presentation object.				


if (RdChkVer)                  // If the version is 1.0  ReadLong();                  // Format ID  if (RdChkString())           // if Class String is either                               // METAFILEPICT or BITMAP or DIB.    ReadLong();                // Width in mmhimetric.    ReadLong();                // Height in mmhimetric.    EatBytes(ReadLong());      // Presentation data size and data itself  else    if (!ReadLong())           // if Clipboard format value is NULL      EatBytes(ReadLong());    // Read Clipboard format name.    EatBytes(ReadLong());      // Presentation data size and data itself.				


OLEVer = ReadLong();OLEVer = (((WORD)(LOBYTE(OLEVer))) << 8 | (WORD) HIBYTE(OLEVer);if (OLEVer == 0x0100)           // Always use Hex value.  return TRUE;else  return FALSE;				
Additional references: 3.10

Article ID: 99340 - Last Review: 10/30/2003 15:31:25 - Revision: 3.0

Microsoft Windows Software Development Kit 3.0, Microsoft Windows Software Development Kit 3.1

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