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https://github.com/PSI-Rockin/DobieStation.git
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92 lines
2.6 KiB
C
92 lines
2.6 KiB
C
/*
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* zlib_decompress.c - decompress with a zlib wrapper
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*
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* Originally public domain; changes after 2016-09-07 are copyrighted.
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*
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* Copyright 2016 Eric Biggers
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use,
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* copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following
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* conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*/
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#include "unaligned.h"
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#include "zlib_constants.h"
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#include "libdeflate.h"
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LIBDEFLATEAPI enum libdeflate_result
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libdeflate_zlib_decompress(struct libdeflate_decompressor *d,
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const void *in, size_t in_nbytes,
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void *out, size_t out_nbytes_avail,
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size_t *actual_out_nbytes_ret)
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{
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const u8 *in_next = in;
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const u8 * const in_end = in_next + in_nbytes;
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u16 hdr;
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size_t actual_out_nbytes;
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enum libdeflate_result result;
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if (in_nbytes < ZLIB_MIN_OVERHEAD)
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return LIBDEFLATE_BAD_DATA;
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/* 2 byte header: CMF and FLG */
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hdr = get_unaligned_be16(in_next);
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in_next += 2;
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/* FCHECK */
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if ((hdr % 31) != 0)
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return LIBDEFLATE_BAD_DATA;
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/* CM */
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if (((hdr >> 8) & 0xF) != ZLIB_CM_DEFLATE)
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return LIBDEFLATE_BAD_DATA;
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/* CINFO */
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if ((hdr >> 12) > ZLIB_CINFO_32K_WINDOW)
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return LIBDEFLATE_BAD_DATA;
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/* FDICT */
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if ((hdr >> 5) & 1)
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return LIBDEFLATE_BAD_DATA;
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/* Compressed data */
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result = libdeflate_deflate_decompress(d, in_next,
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in_end - ZLIB_FOOTER_SIZE - in_next,
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out, out_nbytes_avail,
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actual_out_nbytes_ret);
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if (result != LIBDEFLATE_SUCCESS)
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return result;
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if (actual_out_nbytes_ret)
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actual_out_nbytes = *actual_out_nbytes_ret;
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else
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actual_out_nbytes = out_nbytes_avail;
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in_next = in_end - ZLIB_FOOTER_SIZE;
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/* ADLER32 */
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if (libdeflate_adler32(1, out, actual_out_nbytes) !=
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get_unaligned_be32(in_next))
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return LIBDEFLATE_BAD_DATA;
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return LIBDEFLATE_SUCCESS;
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}
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