xiph.c (2420B)
1 /* 2 * Copyright (C) 2007 The FFmpeg Project 3 * 4 * This file is part of FFmpeg. 5 * 6 * FFmpeg is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * FFmpeg is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with FFmpeg; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19 */ 20 21 #include <limits.h> 22 #include "libavutil/error.h" 23 #include "libavutil/intreadwrite.h" 24 #include "xiph.h" 25 26 int avpriv_split_xiph_headers(const uint8_t *extradata, int extradata_size, 27 int first_header_size, const uint8_t *header_start[3], 28 int header_len[3]) 29 { 30 int i; 31 32 if (extradata_size >= 6 && AV_RB16(extradata) == first_header_size) { 33 int overall_len = 6; 34 for (i=0; i<3; i++) { 35 header_len[i] = AV_RB16(extradata); 36 extradata += 2; 37 header_start[i] = extradata; 38 extradata += header_len[i]; 39 if (overall_len > extradata_size - header_len[i]) 40 return AVERROR_INVALIDDATA; 41 overall_len += header_len[i]; 42 } 43 } else if (extradata_size >= 3 && extradata_size < INT_MAX - 0x1ff && extradata[0] == 2) { 44 int overall_len = 3; 45 extradata++; 46 for (i=0; i<2; i++, extradata++) { 47 header_len[i] = 0; 48 for (; overall_len < extradata_size && *extradata==0xff; extradata++) { 49 header_len[i] += 0xff; 50 overall_len += 0xff + 1; 51 } 52 header_len[i] += *extradata; 53 overall_len += *extradata; 54 if (overall_len > extradata_size) 55 return AVERROR_INVALIDDATA; 56 } 57 header_len[2] = extradata_size - overall_len; 58 header_start[0] = extradata; 59 header_start[1] = header_start[0] + header_len[0]; 60 header_start[2] = header_start[1] + header_len[1]; 61 } else { 62 return -1; 63 } 64 return 0; 65 }