Microsoft KB Archive/102354

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INFO: Calculating the TrueType Checksum

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Q102354

3.10 3.50 3.51 | 4.00 WINDOWS NT | WINDOWS kbgraphic

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The information in this article applies to:


 * Microsoft Win32 Application Programming Interface (API), used with:
 * Microsoft Windows NT Server versions 3.5, 3.51, 4.0
 * Microsoft Windows NT Workstation versions 3.5, 3.51, 4.0
 * Microsoft Windows 95

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SUMMARY
To calculate a TrueType checksum:


 * 1) Sum all the ULONGS in the .ttf file, except the checkSumAdjust field (which contains the calculated checksum). Note that TrueType files are big-endian, while Windows and Windows NT are little-endian, so the bytes must be swapped before they are summed.
 * 2) Subtract the result from the magic number 0xb1b0afba.

Example

 * 1) Open the SYMBOL.ttf distributed with Windows NT. It is 64492 bytes long.
 * 2) Step through the 16123 ULONGS, summing each one, except for the checkSumAdjust field for the file (which in this case is 0xa7a81151).
 * 3) Subtract the result from 0xb1b0afba. The result is 0xa7a81151.

The TrueType font file specification is available from several sources: the specifications section of the MSDN library CD or the Microsoft Typography WEB site at:

"http://www.microsoft.com/typography" Additional query words: 3.00 3.10 3.50 4.00 5.0 95 98

Keywords : kbOSWinNT350 kbOSWinNT351 kbOSWinNT400 kbSDKWin32 kbOSWin95 kbDSupport

Issue type : kbinfo

Technology : kbAudDeveloper kbWin32sSearch kbWin32API