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76 lines
3.0 KiB
76 lines
3.0 KiB
/*****************************************************************************
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* *
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* ZECK.H *
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* *
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* Copyright (C) Microsoft Corporation 1990. *
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* All Rights reserved. *
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* *
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******************************************************************************
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* *
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* Module Intent *
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* *
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* Zeck compression routines for bitmaps & topic 2K blocks.
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* *
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*****************************************************************************/
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// This structure is passed to the compression routine to specify ranges
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// in which to suppress compression:
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typedef struct struct_suppresszeck SUPPRESSZECK, *QSUPPRESSZECK;
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struct struct_suppresszeck {
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RB rbSuppress; // beginning of range for suppression.
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UINT16 cbSuppress; // number of bytes to suppress compression.
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RB rbNewpos; // pointer into dest buffer where suppressed range
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// ended up after compression (an OUT param value).
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UINT16 iBitdex; // offset from rbNewpos of zeck code bits, used when
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// back patching.
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QSUPPRESSZECK next; // next suppression range in this list.
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};
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#define BITDEX_NONE ((UINT16)-1) // indicates no compression took place, and
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// backpatch should not adjust for the
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// code bits.
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/* LcbCompressZeck -
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*
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* This is the only entry point into zeck compression. Compresses 'cbSrc'
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* bytes at 'rbSrc' into the buffer at 'rbDest', suppressing compression
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* for bytes specified by the qSuppress linked list.
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*
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* rbSrc - IN huge pointer to source buffer.
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* rbDest- IN huge pointer to dest buffer.
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* cbSrc - IN count of bytes to be compressed.
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* cbDest- IN limit count of bytes to put in rbDest - used to create
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* the 2K topic blocks.
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* qulSrcUsed- OUT count of src bytes compressed into rbDest (needed when
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* a cbDest limit is used).
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* qSuppress IN OUT linked list of compression suppression specifiers,
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* the out value is where the suppression ranges ended
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* up in the rbDest buffer.
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*
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* RETURNS: length of compressed data put in rbDest, 0 for error.
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*/
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#define COMPRESS_CBNONE 0 // passed as cbDest when no limit is to apply.
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#define COMPRESS_SUPPRESSNIL NULL // passed as qSuppress when no
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// suppression is desired
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DWORD STDCALL LcbCompressZeck( RB rbSrc, RB rbDest, DWORD cbSrc, DWORD cbDest,
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QUL qulSrcUsed, QSUPPRESSZECK qSuppress );
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BOOL STDCALL FAllocateZeckGlobals( void );
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void STDCALL FreeZeckGlobals( void );
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// this define allows callers to use the routine w/o knowing about the special
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// cbDest,qulSrcUsed, and qSuppress params:
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#define LcbCompressZecksimple( rbSrc, rbDest, cbSrc ) \
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LcbCompressZeck( rbSrc, rbDest, cbSrc, COMPRESS_CBNONE, NULL, \
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COMPRESS_SUPPRESSNIL )
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VOID STDCALL VMemBackpatchZeck( QSUPPRESSZECK qsuppresszeck, DWORD ulOffset,
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DWORD ulValue );
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BOOL STDCALL FDiskBackpatchZeck( HF hf, DWORD fcl, DWORD ulOffset, UINT16 iBitdex,
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DWORD ulValue );
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DWORD STDCALL LcbUncompressZeck( RB rbSrc, RB rbDest, DWORD cbSrc );
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