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/*
* Microsoft Confidential * Copyright (C) Microsoft Corporation 1996 * All Rights Reserved. * * LDI.C: LZX Decompression Interface * * History: * 03-Jul-1996 jforbes Initial version. */
/* --- preprocessor ------------------------------------------------------- */
#include <stdio.h> /* for NULL */
#include "decoder.h"
#include "decapi.h"
#include "ldi.h" /* types, prototype verification, error codes */
#define MAX_GROWTH 6144 /* see encoder.h */
typedef ULONG SIGNATURE; /* structure signature */
struct LDI_CONTEXT /* private structure */{ SIGNATURE signature; /* for validation */ PFNALLOC pfnAlloc; /* where the alloc() is */ PFNFREE pfnFree; /* where the free() is */ PFNOPEN pfnOpen; /* open a file callback or NULL */ PFNREAD pfnRead; /* read a file callback */ PFNWRITE pfnWrite; /* write a file callback */ PFNCLOSE pfnClose; /* close a file callback */ PFNSEEK pfnSeek; /* seek in file callback */ UINT cbDataBlockMax; /* promised max data size */ UINT fCPUtype; /* CPU we're running on, QDI_CPU_xxx */ t_decoder_context *decoder_context;};
typedef struct LDI_CONTEXT FAR *PMDC_CONTEXT; /* a pointer to one */
/* MAKE_SIGNATURE - Construct a structure signature
* * Entry: * a,b,c,d - four characters * * Exit: * Returns constructed SIGNATURE * * Example: * strct->signature = MAKE_SIGNATURE('b','e','n','s') */
#define MAKE_SIGNATURE(a,b,c,d) (a + (b<<8) + (c<<16) + (d<<24))
#define BAD_SIGNATURE (0L)
#define LDI_SIGNATURE MAKE_SIGNATURE('L','D','I','C')
/* --- LDI context structure ---------------------------------------------- */
#define PMDCfromHMD(h) ((PMDC_CONTEXT)(h)) /* handle to pointer */
#define HMDfromPMDC(p) ((LDI_CONTEXT_HANDLE)(p)) /* pointer to handle */
/* --- LDICreateDecompression() ------------------------------------------- */#include <stdio.h>
int FAR DIAMONDAPI LDICreateDecompression( UINT FAR * pcbDataBlockMax, /* max uncompressed data block */ void FAR * pvConfiguration, /* implementation-defined */ PFNALLOC pfnma, /* Memory allocation function */ PFNFREE pfnmf, /* Memory free function */ UINT FAR * pcbSrcBufferMin, /* gets required input buffer */ LDI_CONTEXT_HANDLE FAR * pmdhHandle, /* gets newly-created handle */ PFNOPEN pfnopen, /* open a file callback */ PFNREAD pfnread, /* read a file callback */ PFNWRITE pfnwrite, /* write a file callback */ PFNCLOSE pfnclose, /* close a file callback */ PFNSEEK pfnseek) /* seek in file callback */{
PMDC_CONTEXT context; /* new context */ PFLZXDECOMPRESS pConfig; /* to get configuration details */
pConfig = pvConfiguration; /* get a pointer we can use */
*pcbSrcBufferMin = /* we'll expand sometimes */ *pcbDataBlockMax + MAX_GROWTH;
if (pmdhHandle == NULL) /* if no context requested, */ { return(MDI_ERROR_NO_ERROR); /* return from query mode */ }
*pmdhHandle = (LDI_CONTEXT_HANDLE) 0; /* wait until it's valid */
context = pfnma(sizeof(struct LDI_CONTEXT));
if (context == NULL) { return(MDI_ERROR_NOT_ENOUGH_MEMORY); /* if can't allocate */ }
context->decoder_context = pfnma(sizeof(t_decoder_context));
if (context->decoder_context == NULL) { pfnmf(context); return MDI_ERROR_NOT_ENOUGH_MEMORY; }
context->pfnAlloc = pfnma; /* remember where alloc() is */ context->pfnFree = pfnmf; /* remember where free() is */ context->pfnOpen = pfnopen; /* remember where pfnopen() is */ context->pfnRead = pfnread; /* remember where pfnread() is */ context->pfnWrite = pfnwrite; /* remember where pfnwrite() is */ context->pfnClose = pfnclose; /* remember where pfnclose() is */ context->pfnSeek = pfnseek; /* remember where pfnseek() is */ context->cbDataBlockMax = *pcbDataBlockMax; /* remember agreement */ context->fCPUtype = (UINT) pConfig->fCPUtype; /* remember CPU type */ context->signature = LDI_SIGNATURE; /* install signature */
if (LZX_DecodeInit( context->decoder_context, pConfig->WindowSize, pfnma, pfnmf, pfnopen, pfnread, pfnwrite, pfnclose, pfnseek) == false) { pfnmf(context); return (MDI_ERROR_NOT_ENOUGH_MEMORY); }
/* pass context back to caller */ *pmdhHandle = HMDfromPMDC(context);
return(MDI_ERROR_NO_ERROR); /* tell caller all is well */}
/* --- LDIDecompress() ---------------------------------------------------- */int FAR DIAMONDAPI LDIDecompress( LDI_CONTEXT_HANDLE hmd, /* decompression context */ void FAR * pbSrc, /* source buffer */ UINT cbSrc, /* source actual size */ void FAR * pbDst, /* target buffer */ UINT FAR * pcbResult) /* gets actual target size */{ PMDC_CONTEXT context; /* pointer to the context */ int result; /* return code */ long bytes_to_decode; long total_bytes_written = 0;
context = PMDCfromHMD(hmd); /* get pointer from handle */
if (context->signature != LDI_SIGNATURE) { return(MDI_ERROR_BAD_PARAMETERS); /* missing signature */ }
if (*pcbResult > context->cbDataBlockMax) { return(MDI_ERROR_BUFFER_OVERFLOW); /* violated max block promise */ }
#if 0
if (cbSrc == 0) return MDI_ERROR_NO_ERROR;#endif
bytes_to_decode = (long) *pcbResult;
result = LZX_Decode( context->decoder_context, bytes_to_decode, pbSrc, cbSrc, pbDst, bytes_to_decode, &total_bytes_written );
*pcbResult = (UINT) total_bytes_written;
if (result) return MDI_ERROR_FAILED; else return MDI_ERROR_NO_ERROR;}
/* --- LDIResetDecompression() -------------------------------------------- */
int FAR DIAMONDAPI LDIResetDecompression(LDI_CONTEXT_HANDLE hmd){ PMDC_CONTEXT context; /* pointer to the context */
context = PMDCfromHMD(hmd); /* get pointer from handle */
if (context->signature != LDI_SIGNATURE) { return(MDI_ERROR_BAD_PARAMETERS); /* missing signature */ }
LZX_DecodeNewGroup(context->decoder_context);
return(MDI_ERROR_NO_ERROR); /* if tag is OK */}
/* --- LDIDestroyDecompression() ------------------------------------------ */
int FAR DIAMONDAPI LDIDestroyDecompression(LDI_CONTEXT_HANDLE hmd){ PMDC_CONTEXT context; /* pointer to the context */
context = PMDCfromHMD(hmd); /* get pointer from handle */
if (context->signature != LDI_SIGNATURE) { return(MDI_ERROR_BAD_PARAMETERS); /* missing signature */ }
LZX_DecodeFree(context->decoder_context);
context->signature = BAD_SIGNATURE; /* destroy signature */
context->pfnFree(context->decoder_context); context->pfnFree(context); /* self-destruct */
return(MDI_ERROR_NO_ERROR); /* success */}
/* --- LDIGetWindow() ---------------------------------------------------- */#ifndef BIT16
int FAR DIAMONDAPI LDIGetWindow( LDI_CONTEXT_HANDLE hmd, /* decompression context */ BYTE FAR ** ppWindow, /* pointer to window start */ long * pFileOffset, /* offset in folder */ long * pWindowOffset, /* offset in window */ long * pcbBytesAvail) /* bytes avail from window start */{ PMDC_CONTEXT context; t_decoder_context *dec_context;
context = PMDCfromHMD(hmd); /* get pointer from handle */ dec_context = context->decoder_context;
*ppWindow = dec_context->dec_mem_window;
// window is a circular buffer
if ((ulong) dec_context->dec_position_at_start < dec_context->dec_window_size) { *pWindowOffset = 0; *pFileOffset = 0; *pcbBytesAvail = dec_context->dec_position_at_start; } else { *pWindowOffset = dec_context->dec_position_at_start & (dec_context->dec_window_size - 1); *pcbBytesAvail = dec_context->dec_window_size; *pFileOffset = dec_context->dec_position_at_start - dec_context->dec_window_size; }
return MDI_ERROR_NO_ERROR;}#endif
/* ------------------------------------------------------------------------ */
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