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/*
* tinfzlib - tiny zlib decompressor
*
* This version of tinfzlib was modified for use with m1n1.
*
* Copyright (c) 2003-2019 Joergen Ibsen
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must
* not claim that you wrote the original software. If you use this
* software in a product, an acknowledgment in the product
* documentation would be appreciated but is not required.
*
* 2. Altered source versions must be plainly marked as such, and must
* not be misrepresented as being the original software.
*
* 3. This notice may not be removed or altered from any source
* distribution.
*/
#include "tinf.h"
static unsigned int read_be32(const unsigned char *p)
{
return ((unsigned int) p[0] << 24)
| ((unsigned int) p[1] << 16)
| ((unsigned int) p[2] << 8)
| ((unsigned int) p[3]);
}
int tinf_zlib_uncompress(void *dest, unsigned int *destLen,
const void *source, unsigned int *sourceLen)
{
const unsigned char *src = (const unsigned char *) source;
unsigned char *dst = (unsigned char *) dest;
unsigned int a32;
int res;
unsigned char cmf, flg;
unsigned int sourceDataLen = sourceLen ? *sourceLen - 6 : 0;
/* -- Check header -- */
/* Check room for at least 2 byte header and 4 byte trailer */
if (*sourceLen && *sourceLen < 6) {
return TINF_DATA_ERROR;
}
/* Get header bytes */
cmf = src[0];
flg = src[1];
/* Check checksum */
if ((256 * cmf + flg) % 31) {
return TINF_DATA_ERROR;
}
/* Check method is deflate */
if ((cmf & 0x0F) != 8) {
return TINF_DATA_ERROR;
}
/* Check window size is valid */
if ((cmf >> 4) > 7) {
return TINF_DATA_ERROR;
}
/* Check there is no preset dictionary */
if (flg & 0x20) {
return TINF_DATA_ERROR;
}
/* -- Decompress data -- */
res = tinf_uncompress(dst, destLen, src + 2, &sourceDataLen);
if (res != TINF_OK) {
return TINF_DATA_ERROR;
}
/* -- Check Adler-32 checksum -- */
a32 = read_be32(&src[sourceDataLen + 2]);
if (a32 != tinf_adler32(dst, *destLen)) {
return TINF_DATA_ERROR;
}
if (sourceLen)
*sourceLen = sourceDataLen + 6;
return TINF_OK;
}
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