libavcodec/targa.c
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00001 /*
00002  * Targa (.tga) image decoder
00003  * Copyright (c) 2006 Konstantin Shishkov
00004  *
00005  * This file is part of Libav.
00006  *
00007  * Libav is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * Libav is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with Libav; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include "libavutil/intreadwrite.h"
00023 #include "libavutil/imgutils.h"
00024 #include "avcodec.h"
00025 #include "bytestream.h"
00026 #include "targa.h"
00027 
00028 typedef struct TargaContext {
00029     AVFrame picture;
00030 
00031     int width, height;
00032     int bpp;
00033     int color_type;
00034     int compression_type;
00035 } TargaContext;
00036 
00037 #define CHECK_BUFFER_SIZE(buf, buf_end, needed, where) \
00038     if(needed > buf_end - buf){ \
00039         av_log(avctx, AV_LOG_ERROR, "Problem: unexpected end of data while reading " where "\n"); \
00040         return -1; \
00041     } \
00042 
00043 static int targa_decode_rle(AVCodecContext *avctx, TargaContext *s, const uint8_t *src, int src_size, uint8_t *dst, int w, int h, int stride, int bpp)
00044 {
00045     int i, x, y;
00046     int depth = (bpp + 1) >> 3;
00047     int type, count;
00048     int diff;
00049     const uint8_t *src_end = src + src_size;
00050 
00051     diff = stride - w * depth;
00052     x = y = 0;
00053     while(y < h){
00054         CHECK_BUFFER_SIZE(src, src_end, 1, "image type");
00055         type = *src++;
00056         count = (type & 0x7F) + 1;
00057         type &= 0x80;
00058         if((x + count > w) && (x + count + 1 > (h - y) * w)){
00059             av_log(avctx, AV_LOG_ERROR, "Packet went out of bounds: position (%i,%i) size %i\n", x, y, count);
00060             return -1;
00061         }
00062         if(type){
00063             CHECK_BUFFER_SIZE(src, src_end, depth, "image data");
00064         }else{
00065             CHECK_BUFFER_SIZE(src, src_end, count * depth, "image data");
00066         }
00067         for(i = 0; i < count; i++){
00068             switch(depth){
00069             case 1:
00070                 *dst = *src;
00071                 break;
00072             case 2:
00073                 *((uint16_t*)dst) = AV_RL16(src);
00074                 break;
00075             case 3:
00076                 dst[0] = src[0];
00077                 dst[1] = src[1];
00078                 dst[2] = src[2];
00079                 break;
00080             case 4:
00081                 *((uint32_t*)dst) = AV_RL32(src);
00082                 break;
00083             }
00084             dst += depth;
00085             if(!type)
00086                 src += depth;
00087 
00088             x++;
00089             if(x == w){
00090                 x = 0;
00091                 y++;
00092                 dst += diff;
00093             }
00094         }
00095         if(type)
00096             src += depth;
00097     }
00098     return src_size;
00099 }
00100 
00101 static int decode_frame(AVCodecContext *avctx,
00102                         void *data, int *data_size,
00103                         AVPacket *avpkt)
00104 {
00105     const uint8_t *buf = avpkt->data;
00106     const uint8_t *buf_end = avpkt->data + avpkt->size;
00107     TargaContext * const s = avctx->priv_data;
00108     AVFrame *picture = data;
00109     AVFrame * const p= (AVFrame*)&s->picture;
00110     uint8_t *dst;
00111     int stride;
00112     int idlen, compr, y, w, h, bpp, flags;
00113     int first_clr, colors, csize;
00114 
00115     /* parse image header */
00116     CHECK_BUFFER_SIZE(buf, buf_end, 18, "header");
00117     idlen = *buf++;
00118     buf++; /* pal */
00119     compr = *buf++;
00120     first_clr = AV_RL16(buf); buf += 2;
00121     colors = AV_RL16(buf); buf += 2;
00122     csize = *buf++;
00123     buf += 2; /* x */
00124     y = AV_RL16(buf); buf += 2;
00125     w = AV_RL16(buf); buf += 2;
00126     h = AV_RL16(buf); buf += 2;
00127     bpp = *buf++;
00128     flags = *buf++;
00129     //skip identifier if any
00130     CHECK_BUFFER_SIZE(buf, buf_end, idlen, "identifiers");
00131     buf += idlen;
00132     s->bpp = bpp;
00133     s->width = w;
00134     s->height = h;
00135     switch(s->bpp){
00136     case 8:
00137         avctx->pix_fmt = ((compr & (~TGA_RLE)) == TGA_BW) ? PIX_FMT_GRAY8 : PIX_FMT_PAL8;
00138         break;
00139     case 15:
00140         avctx->pix_fmt = PIX_FMT_RGB555;
00141         break;
00142     case 16:
00143         avctx->pix_fmt = PIX_FMT_RGB555;
00144         break;
00145     case 24:
00146         avctx->pix_fmt = PIX_FMT_BGR24;
00147         break;
00148     case 32:
00149         avctx->pix_fmt = PIX_FMT_RGB32;
00150         break;
00151     default:
00152         av_log(avctx, AV_LOG_ERROR, "Bit depth %i is not supported\n", s->bpp);
00153         return -1;
00154     }
00155 
00156     if(s->picture.data[0])
00157         avctx->release_buffer(avctx, &s->picture);
00158 
00159     if(av_image_check_size(w, h, 0, avctx))
00160         return -1;
00161     if(w != avctx->width || h != avctx->height)
00162         avcodec_set_dimensions(avctx, w, h);
00163     if(avctx->get_buffer(avctx, p) < 0){
00164         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00165         return -1;
00166     }
00167     if(flags & 0x20){
00168         dst = p->data[0];
00169         stride = p->linesize[0];
00170     }else{ //image is upside-down
00171         dst = p->data[0] + p->linesize[0] * (h - 1);
00172         stride = -p->linesize[0];
00173     }
00174 
00175     if(colors){
00176         int pal_size, pal_sample_size;
00177         if((colors + first_clr) > 256){
00178             av_log(avctx, AV_LOG_ERROR, "Incorrect palette: %i colors with offset %i\n", colors, first_clr);
00179             return -1;
00180         }
00181         switch (csize) {
00182         case 24: pal_sample_size = 3; break;
00183         case 16:
00184         case 15: pal_sample_size = 2; break;
00185         default:
00186             av_log(avctx, AV_LOG_ERROR, "Palette entry size %i bits is not supported\n", csize);
00187             return -1;
00188         }
00189         pal_size = colors * pal_sample_size;
00190         CHECK_BUFFER_SIZE(buf, buf_end, pal_size, "color table");
00191         if(avctx->pix_fmt != PIX_FMT_PAL8)//should not occur but skip palette anyway
00192             buf += pal_size;
00193         else{
00194             int t;
00195             uint32_t *pal = ((uint32_t *)p->data[1]) + first_clr;
00196 
00197             switch (pal_sample_size) {
00198             case 3:
00199                 /* RGB24 */
00200                 for (t = 0; t < colors; t++)
00201                     *pal++ = bytestream_get_le24(&buf);
00202                 break;
00203             case 2:
00204                 /* RGB555 */
00205                 for (t = 0; t < colors; t++) {
00206                     uint32_t v = bytestream_get_le16(&buf);
00207                     v = ((v & 0x7C00) <<  9) |
00208                         ((v & 0x03E0) <<  6) |
00209                         ((v & 0x001F) <<  3);
00210                     /* left bit replication */
00211                     v |= (v & 0xE0E0E0U) >> 5;
00212                     *pal++ = v;
00213                 }
00214                 break;
00215             }
00216             p->palette_has_changed = 1;
00217         }
00218     }
00219     if((compr & (~TGA_RLE)) == TGA_NODATA)
00220         memset(p->data[0], 0, p->linesize[0] * s->height);
00221     else{
00222         if(compr & TGA_RLE){
00223             int res = targa_decode_rle(avctx, s, buf, buf_end - buf, dst, avctx->width, avctx->height, stride, bpp);
00224             if (res < 0)
00225                 return -1;
00226             buf += res;
00227         }else{
00228             size_t img_size = s->width * ((s->bpp + 1) >> 3);
00229             CHECK_BUFFER_SIZE(buf, buf_end, img_size, "image data");
00230             for(y = 0; y < s->height; y++){
00231 #if HAVE_BIGENDIAN
00232                 int x;
00233                 if((s->bpp + 1) >> 3 == 2){
00234                     uint16_t *dst16 = (uint16_t*)dst;
00235                     for(x = 0; x < s->width; x++)
00236                         dst16[x] = AV_RL16(buf + x * 2);
00237                 }else if((s->bpp + 1) >> 3 == 4){
00238                     uint32_t *dst32 = (uint32_t*)dst;
00239                     for(x = 0; x < s->width; x++)
00240                         dst32[x] = AV_RL32(buf + x * 4);
00241                 }else
00242 #endif
00243                     memcpy(dst, buf, img_size);
00244 
00245                 dst += stride;
00246                 buf += img_size;
00247             }
00248         }
00249     }
00250 
00251     *picture= *(AVFrame*)&s->picture;
00252     *data_size = sizeof(AVPicture);
00253 
00254     return avpkt->size;
00255 }
00256 
00257 static av_cold int targa_init(AVCodecContext *avctx){
00258     TargaContext *s = avctx->priv_data;
00259 
00260     avcodec_get_frame_defaults((AVFrame*)&s->picture);
00261     avctx->coded_frame= (AVFrame*)&s->picture;
00262 
00263     return 0;
00264 }
00265 
00266 static av_cold int targa_end(AVCodecContext *avctx){
00267     TargaContext *s = avctx->priv_data;
00268 
00269     if(s->picture.data[0])
00270         avctx->release_buffer(avctx, &s->picture);
00271 
00272     return 0;
00273 }
00274 
00275 AVCodec ff_targa_decoder = {
00276     .name           = "targa",
00277     .type           = AVMEDIA_TYPE_VIDEO,
00278     .id             = CODEC_ID_TARGA,
00279     .priv_data_size = sizeof(TargaContext),
00280     .init           = targa_init,
00281     .close          = targa_end,
00282     .decode         = decode_frame,
00283     .capabilities   = CODEC_CAP_DR1,
00284     .long_name = NULL_IF_CONFIG_SMALL("Truevision Targa image"),
00285 };