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