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101 lines (76 loc) · 2.48 KB
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/*
* tinfzlib - tiny zlib decompressor
*
* Copyright (c) 2003 by Joergen Ibsen / Jibz
* All Rights Reserved
*
* http://www.ibsensoftware.com/
*
* 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"
int tinf_zlib_uncompress(void *dest, unsigned int *destLen,
const void *source, unsigned int sourceLen)
{
TINF_DATA d;
int res;
/* initialise data */
d.source = (const unsigned char *)source;
d.destStart = (unsigned char *)dest;
d.destRemaining = *destLen;
res = tinf_zlib_uncompress_dyn(&d, sourceLen);
*destLen = d.dest - d.destStart;
return res;
}
int tinf_zlib_uncompress_dyn(TINF_DATA *d, unsigned int sourceLen)
{
unsigned int a32;
int res;
unsigned char cmf, flg;
/* -- get header bytes -- */
cmf = d->source[0];
flg = d->source[1];
/* -- check format -- */
/* 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;
/* -- get adler32 checksum -- */
a32 = d->source[sourceLen - 4];
a32 = 256*a32 + d->source[sourceLen - 3];
a32 = 256*a32 + d->source[sourceLen - 2];
a32 = 256*a32 + d->source[sourceLen - 1];
d->source += 2;
/* -- inflate -- */
res = tinf_uncompress_dyn(d);
if (res != TINF_OK) return res;
/* -- check adler32 checksum -- */
if (a32 != tinf_adler32(d->destStart, d->dest - d->destStart)) return TINF_DATA_ERROR;
return TINF_OK;
}