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110 lines
2.7 KiB
110 lines
2.7 KiB
/* |
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* tinfgzip - tiny gzip 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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* Copyright (c) 2014-2016 by Paul Sokolovsky |
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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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#define FTEXT 1 |
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#define FHCRC 2 |
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#define FEXTRA 4 |
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#define FNAME 8 |
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#define FCOMMENT 16 |
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void tinf_skip_bytes(TINF_DATA *d, int num); |
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uint16_t tinf_get_uint16(TINF_DATA *d); |
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void tinf_skip_bytes(TINF_DATA *d, int num) |
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{ |
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while (num--) uzlib_get_byte(d); |
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} |
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uint16_t tinf_get_uint16(TINF_DATA *d) |
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{ |
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unsigned int v = uzlib_get_byte(d); |
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v = (uzlib_get_byte(d) << 8) | v; |
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return v; |
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} |
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int uzlib_gzip_parse_header(TINF_DATA *d) |
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{ |
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unsigned char flg; |
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/* -- check format -- */ |
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/* check id bytes */ |
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if (uzlib_get_byte(d) != 0x1f || uzlib_get_byte(d) != 0x8b) return TINF_DATA_ERROR; |
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/* check method is deflate */ |
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if (uzlib_get_byte(d) != 8) return TINF_DATA_ERROR; |
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/* get flag byte */ |
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flg = uzlib_get_byte(d); |
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/* check that reserved bits are zero */ |
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if (flg & 0xe0) return TINF_DATA_ERROR; |
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/* -- find start of compressed data -- */ |
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/* skip rest of base header of 10 bytes */ |
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tinf_skip_bytes(d, 6); |
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/* skip extra data if present */ |
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if (flg & FEXTRA) |
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{ |
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unsigned int xlen = tinf_get_uint16(d); |
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tinf_skip_bytes(d, xlen); |
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} |
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/* skip file name if present */ |
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if (flg & FNAME) { while (uzlib_get_byte(d)); } |
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/* skip file comment if present */ |
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if (flg & FCOMMENT) { while (uzlib_get_byte(d)); } |
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/* check header crc if present */ |
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if (flg & FHCRC) |
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{ |
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/*unsigned int hcrc =*/ tinf_get_uint16(d); |
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// TODO: Check! |
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// if (hcrc != (tinf_crc32(src, start - src) & 0x0000ffff)) |
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// return TINF_DATA_ERROR; |
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} |
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/* initialize for crc32 checksum */ |
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d->checksum_type = TINF_CHKSUM_CRC; |
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d->checksum = ~0; |
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return TINF_OK; |
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}
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