kopia lustrzana https://github.com/micropython/micropython
102 wiersze
2.5 KiB
C
102 wiersze
2.5 KiB
C
/*
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* tinfzlib - tiny zlib decompressor
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*
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* Copyright (c) 2003 by Joergen Ibsen / Jibz
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* All Rights Reserved
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*
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* http://www.ibsensoftware.com/
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*
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* This software is provided 'as-is', without any express
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* or implied warranty. In no event will the authors be
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* held liable for any damages arising from the use of
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* this software.
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*
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* Permission is granted to anyone to use this software
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* for any purpose, including commercial applications,
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* and to alter it and redistribute it freely, subject to
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* the following restrictions:
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*
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* 1. The origin of this software must not be
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* misrepresented; you must not claim that you
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* wrote the original software. If you use this
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* software in a product, an acknowledgment in
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* the product documentation would be appreciated
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* but is not required.
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*
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* 2. Altered source versions must be plainly marked
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* as such, and must not be misrepresented as
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* being the original software.
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*
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* 3. This notice may not be removed or altered from
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* any source distribution.
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*/
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#include "tinf.h"
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int tinf_zlib_uncompress(void *dest, unsigned int *destLen,
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const void *source, unsigned int sourceLen)
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{
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TINF_DATA d;
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int res;
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/* initialise data */
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d.source = (const unsigned char *)source;
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d.destStart = (unsigned char *)dest;
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d.destRemaining = *destLen;
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res = tinf_zlib_uncompress_dyn(&d, sourceLen);
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*destLen = d.dest - d.destStart;
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return res;
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}
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int tinf_zlib_uncompress_dyn(TINF_DATA *d, unsigned int sourceLen)
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{
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unsigned int a32;
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int res;
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unsigned char cmf, flg;
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/* -- get header bytes -- */
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cmf = d->source[0];
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flg = d->source[1];
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/* -- check format -- */
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/* check checksum */
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if ((256*cmf + flg) % 31) return TINF_DATA_ERROR;
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/* check method is deflate */
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if ((cmf & 0x0f) != 8) return TINF_DATA_ERROR;
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/* check window size is valid */
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if ((cmf >> 4) > 7) return TINF_DATA_ERROR;
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/* check there is no preset dictionary */
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if (flg & 0x20) return TINF_DATA_ERROR;
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/* -- get adler32 checksum -- */
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a32 = d->source[sourceLen - 4];
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a32 = 256*a32 + d->source[sourceLen - 3];
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a32 = 256*a32 + d->source[sourceLen - 2];
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a32 = 256*a32 + d->source[sourceLen - 1];
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d->source += 2;
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/* -- inflate -- */
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res = tinf_uncompress_dyn(d);
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if (res != TINF_OK) return res;
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/* -- check adler32 checksum -- */
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if (a32 != tinf_adler32(d->destStart, d->dest - d->destStart)) return TINF_DATA_ERROR;
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return TINF_OK;
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}
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