mirror of
https://github.com/PSI-Rockin/DobieStation.git
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149 lines
4 KiB
C
149 lines
4 KiB
C
/*
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* gzip_decompress.c - decompress with a gzip 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 "gzip_constants.h"
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#include "unaligned.h"
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#include "libdeflate.h"
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LIBDEFLATEAPI enum libdeflate_result
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libdeflate_gzip_decompress_ex(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_in_nbytes_ret,
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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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u8 flg;
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size_t actual_in_nbytes;
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size_t actual_out_nbytes;
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enum libdeflate_result result;
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if (in_nbytes < GZIP_MIN_OVERHEAD)
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return LIBDEFLATE_BAD_DATA;
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/* ID1 */
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if (*in_next++ != GZIP_ID1)
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return LIBDEFLATE_BAD_DATA;
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/* ID2 */
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if (*in_next++ != GZIP_ID2)
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return LIBDEFLATE_BAD_DATA;
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/* CM */
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if (*in_next++ != GZIP_CM_DEFLATE)
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return LIBDEFLATE_BAD_DATA;
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flg = *in_next++;
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/* MTIME */
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in_next += 4;
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/* XFL */
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in_next += 1;
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/* OS */
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in_next += 1;
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if (flg & GZIP_FRESERVED)
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return LIBDEFLATE_BAD_DATA;
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/* Extra field */
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if (flg & GZIP_FEXTRA) {
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u16 xlen = get_unaligned_le16(in_next);
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in_next += 2;
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if (in_end - in_next < (u32)xlen + GZIP_FOOTER_SIZE)
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return LIBDEFLATE_BAD_DATA;
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in_next += xlen;
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}
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/* Original file name (zero terminated) */
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if (flg & GZIP_FNAME) {
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while (*in_next++ != 0 && in_next != in_end)
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;
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if (in_end - in_next < GZIP_FOOTER_SIZE)
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return LIBDEFLATE_BAD_DATA;
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}
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/* File comment (zero terminated) */
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if (flg & GZIP_FCOMMENT) {
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while (*in_next++ != 0 && in_next != in_end)
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;
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if (in_end - in_next < GZIP_FOOTER_SIZE)
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return LIBDEFLATE_BAD_DATA;
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}
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/* CRC16 for gzip header */
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if (flg & GZIP_FHCRC) {
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in_next += 2;
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if (in_end - in_next < GZIP_FOOTER_SIZE)
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return LIBDEFLATE_BAD_DATA;
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}
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/* Compressed data */
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result = libdeflate_deflate_decompress_ex(d, in_next,
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in_end - GZIP_FOOTER_SIZE - in_next,
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out, out_nbytes_avail,
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&actual_in_nbytes,
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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 += actual_in_nbytes;
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/* CRC32 */
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if (libdeflate_crc32(0, out, actual_out_nbytes) !=
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get_unaligned_le32(in_next))
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return LIBDEFLATE_BAD_DATA;
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in_next += 4;
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/* ISIZE */
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if ((u32)actual_out_nbytes != get_unaligned_le32(in_next))
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return LIBDEFLATE_BAD_DATA;
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in_next += 4;
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if (actual_in_nbytes_ret)
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*actual_in_nbytes_ret = in_next - (u8 *)in;
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return LIBDEFLATE_SUCCESS;
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}
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LIBDEFLATEAPI enum libdeflate_result
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libdeflate_gzip_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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return libdeflate_gzip_decompress_ex(d, in, in_nbytes,
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out, out_nbytes_avail,
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NULL, actual_out_nbytes_ret);
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}
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