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/*
** uncompress.c
**
** Piotr Fusik, 18.11.2001
*/
#include <zlib.h>
int __fastcall__ uncompress (unsigned char* dest, unsigned* destLen,
const unsigned char* source, unsigned sourceLen)
{
unsigned len;
const unsigned char* ptr = source + sourceLen - 4;
unsigned long csum;
/* source[0]: Compression method and flags
bits 0 to 3: Compression method (must be Z_DEFLATED)
bits 4 to 7: Compression info (must be <= 7)
source[1]: Flags
bits 0 to 4: Check bits
bit 5: Preset dictionary (not supported, sorry)
bits 6 to 7: Compression level
*/
if ((source[0] & 0x8f) != Z_DEFLATED || source[1] & 0x20)
return Z_DATA_ERROR;
if ((((unsigned) source[0] << 8) | source[1]) % 31)
return Z_DATA_ERROR;
*destLen = len = inflatemem(dest, source + 2);
csum = adler32(adler32(0L, Z_NULL, 0), dest, len);
if ((unsigned char) csum != ptr[3]
|| (unsigned char) (csum >> 8) != ptr[2]
|| (unsigned char) (csum >> 16) != ptr[1]
|| (unsigned char) (csum >> 24) != ptr[0])
return Z_DATA_ERROR;
return Z_OK;
}
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