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116 lines
3.8 KiB
116 lines
3.8 KiB
/* DEC/CMS REPLACEMENT HISTORY, Element UNZIP.C */
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/* *1 14-NOV-1996 10:26:58 ANIGBOGU "[113914]Decompress data in zip format using the inflate algorithm" */
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/* DEC/CMS REPLACEMENT HISTORY, Element UNZIP.C */
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/* DEC/CMS REPLACEMENT HISTORY, Element UNZIP.C */
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/* PRIVATE FILE
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******************************************************************************
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**
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** (c) Copyright Schlumberger Technology Corp., unpublished work, created 1996.
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**
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** This computer program includes Confidential, Proprietary Information and is
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** a Trade Secret of Schlumberger Technology Corp. All use, disclosure, and/or
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** reproduction is prohibited unless authorized in writing by Schlumberger.
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** All Rights Reserved.
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**
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******************************************************************************
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**
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** compress/unzip.c
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**
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** PURPOSE
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**
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** Decompress data using the inflate algorithm.
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**
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** The code in this file is derived from the file funzip.c written
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** and put in the public domain by Mark Adler.
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**
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**
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** SPECIAL REQUIREMENTS & NOTES
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**
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** AUTHOR
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**
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** J. C. Anigbogu
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** Austin Systems Center
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** Nov 1996
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**
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******************************************************************************
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*/
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#include "comppriv.h"
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#define EXTHDR 16 /* size of extended local header, inc sig */
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/* ===========================================================================
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*
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* IN assertions: the buffer Input contains already the beginning of
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* the compressed data, from offsets inptr to InputSize-1 included.
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* The magic header has already been checked. The output buffer is cleared.
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*/
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CompressStatus_t
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Unzip(
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int Method,
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CompParam_t *Comp
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)
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{
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unsigned long OriginalCRC = 0; /* original crc */
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unsigned long OriginalLength = 0; /* original uncompressed length */
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unsigned long Count; /* counter */
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int Pos;
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unsigned char LocalBuffer[EXTHDR]; /* extended local header */
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unsigned char *Buffer, *Ptr;
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CompressStatus_t Status;
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Comp->pCRC->Compute(NULL, 0); /* initialize crc */
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/* Decompress */
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if (Method == STORED)
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{
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/* Get the crc and original length */
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/* crc32 (see algorithm.doc)
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* uncompressed input size modulo 2^32
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*/
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LocalBuffer[0] = 0; /* To get around lint error 771 */
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for (Pos = 0; Pos < 8; Pos++)
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{
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LocalBuffer[Pos] = (unsigned char)GetByte(Comp); /* may cause an error if EOF */
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}
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OriginalCRC = LG(LocalBuffer);
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OriginalLength = LG(LocalBuffer+4);
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Ptr = Buffer = (unsigned char *)CompressMalloc((unsigned int)OriginalLength, &Status);
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if (Status != COMPRESS_OK)
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return Status;
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for (Count = 0; Count < OriginalLength; Count++)
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*(Ptr++) = (unsigned char)GetByte(Comp);
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WriteBuffer(Comp, Buffer, (unsigned int)OriginalLength);
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Comp->BytesOut = OriginalLength;
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CompressFree((char *)Buffer);
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return COMPRESS_OK;
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}
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if ((Status = Inflate(Comp)) != COMPRESS_OK)
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return Status;
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/* Get the crc and original length */
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/* crc32 (see algorithm.doc)
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* uncompressed input size modulo 2^32
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*/
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LocalBuffer[0] = 0; /* To skirt around lint error 771 */
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for (Pos = 0; Pos < 8; Pos++)
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{
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LocalBuffer[Pos] = (unsigned char)GetByte(Comp); /* may cause an error if EOF */
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}
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OriginalCRC = LG(LocalBuffer);
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OriginalLength = LG(LocalBuffer+4);
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/* Validate decompression */
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if (OriginalCRC != (unsigned __int32)(*Comp->pCRC))
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return CRC_ERROR;
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if (OriginalLength != (unsigned long)Comp->BytesOut)
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return LENGTH_ERROR;
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return COMPRESS_OK;
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}
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