1/* 2 * XBM image format 3 * 4 * Copyright (c) 2012 Paul B Mahol 5 * 6 * This file is part of FFmpeg. 7 * 8 * FFmpeg is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * FFmpeg is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with FFmpeg; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23#include "libavutil/avstring.h" 24#include "libavutil/reverse.h" 25 26#include "avcodec.h" 27#include "codec_internal.h" 28#include "internal.h" 29#include "mathops.h" 30 31static int get_nibble(uint8_t x) 32{ 33 int ret = 255; 34 35 if (x <= '9') { 36 if (x >= '0') 37 ret = x - '0'; 38 } else if (x >= 'a') { 39 if (x <= 'f') 40 ret = x - ('a' - 10); 41 } else if (x >= 'A' && x <= 'F') 42 ret = x - ('A' - 10); 43 return ret; 44} 45 46static int parse_str_int(const uint8_t *p, const uint8_t *end, const uint8_t *key) 47{ 48 int keylen = strlen(key); 49 const uint8_t *e = end - keylen; 50 51 for(; p < e; p++) { 52 if (!memcmp(p, key, keylen)) 53 break; 54 } 55 p += keylen; 56 if (p >= end) 57 return INT_MIN; 58 59 for(; p<end; p++) { 60 char *eptr; 61 int64_t ret = strtol(p, &eptr, 10); 62 if ((const uint8_t *)eptr != p) 63 return ret; 64 } 65 return INT_MIN; 66} 67 68static int xbm_decode_frame(AVCodecContext *avctx, AVFrame *p, 69 int *got_frame, AVPacket *avpkt) 70{ 71 int ret, linesize, i, j; 72 int width = 0; 73 int height = 0; 74 const uint8_t *end, *ptr = avpkt->data; 75 const uint8_t *next; 76 uint8_t *dst; 77 78 avctx->pix_fmt = AV_PIX_FMT_MONOWHITE; 79 end = avpkt->data + avpkt->size; 80 81 width = parse_str_int(avpkt->data, end, "_width"); 82 height = parse_str_int(avpkt->data, end, "_height"); 83 84 if ((ret = ff_set_dimensions(avctx, width, height)) < 0) 85 return ret; 86 87 if ((ret = ff_get_buffer(avctx, p, 0)) < 0) 88 return ret; 89 90 // goto start of image data 91 next = memchr(ptr, '{', avpkt->size); 92 if (!next) 93 next = memchr(ptr, '(', avpkt->size); 94 if (!next) 95 return AVERROR_INVALIDDATA; 96 ptr = next + 1; 97 98 linesize = (avctx->width + 7) / 8; 99 for (i = 0; i < avctx->height; i++) { 100 dst = p->data[0] + i * p->linesize[0]; 101 for (j = 0; j < linesize; j++) { 102 uint8_t nib, val; 103 104 while (ptr < end && *ptr != 'x' && *ptr != '$') 105 ptr++; 106 107 ptr ++; 108 if (ptr < end && (val = get_nibble(*ptr)) <= 15) { 109 ptr++; 110 if ((nib = get_nibble(*ptr)) <= 15) { 111 val = (val << 4) + nib; 112 ptr++; 113 } 114 *dst++ = ff_reverse[val]; 115 if ((val = get_nibble(*ptr)) <= 15 && j+1 < linesize) { 116 j++; 117 ptr++; 118 if ((nib = get_nibble(*ptr)) <= 15) { 119 val = (val << 4) + nib; 120 ptr++; 121 } 122 *dst++ = ff_reverse[val]; 123 } 124 } else { 125 av_log(avctx, AV_LOG_ERROR, 126 "Unexpected data at %.8s.\n", ptr); 127 return AVERROR_INVALIDDATA; 128 } 129 } 130 } 131 132 p->key_frame = 1; 133 p->pict_type = AV_PICTURE_TYPE_I; 134 135 *got_frame = 1; 136 137 return avpkt->size; 138} 139 140const FFCodec ff_xbm_decoder = { 141 .p.name = "xbm", 142 .p.long_name = NULL_IF_CONFIG_SMALL("XBM (X BitMap) image"), 143 .p.type = AVMEDIA_TYPE_VIDEO, 144 .p.id = AV_CODEC_ID_XBM, 145 .p.capabilities = AV_CODEC_CAP_DR1, 146 FF_CODEC_DECODE_CB(xbm_decode_frame), 147}; 148