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FFmpeg/libavcodec/pnm.c

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/*
* PNM image format
* Copyright (c) 2002, 2003 Fabrice Bellard.
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avcodec.h"
#include "pnm.h"
static inline int pnm_space(int c)
{
return c == ' ' || c == '\n' || c == '\r' || c == '\t';
}
static void pnm_get(PNMContext *sc, char *str, int buf_size)
{
char *s;
int c;
/* skip spaces and comments */
for(;;) {
c = *sc->bytestream++;
if (c == '#') {
do {
c = *sc->bytestream++;
} while (c != '\n' && sc->bytestream < sc->bytestream_end);
} else if (!pnm_space(c)) {
break;
}
}
s = str;
while (sc->bytestream < sc->bytestream_end && !pnm_space(c)) {
if ((s - str) < buf_size - 1)
*s++ = c;
c = *sc->bytestream++;
}
*s = '\0';
}
int ff_pnm_decode_header(AVCodecContext *avctx, PNMContext * const s){
char buf1[32], tuple_type[32];
int h, w, depth, maxval;
pnm_get(s, buf1, sizeof(buf1));
if (!strcmp(buf1, "P4")) {
avctx->pix_fmt = PIX_FMT_MONOWHITE;
} else if (!strcmp(buf1, "P5")) {
if (avctx->codec_id == CODEC_ID_PGMYUV)
avctx->pix_fmt = PIX_FMT_YUV420P;
else
avctx->pix_fmt = PIX_FMT_GRAY8;
} else if (!strcmp(buf1, "P6")) {
avctx->pix_fmt = PIX_FMT_RGB24;
} else if (!strcmp(buf1, "P7")) {
w = -1;
h = -1;
maxval = -1;
depth = -1;
tuple_type[0] = '\0';
for(;;) {
pnm_get(s, buf1, sizeof(buf1));
if (!strcmp(buf1, "WIDTH")) {
pnm_get(s, buf1, sizeof(buf1));
w = strtol(buf1, NULL, 10);
} else if (!strcmp(buf1, "HEIGHT")) {
pnm_get(s, buf1, sizeof(buf1));
h = strtol(buf1, NULL, 10);
} else if (!strcmp(buf1, "DEPTH")) {
pnm_get(s, buf1, sizeof(buf1));
depth = strtol(buf1, NULL, 10);
} else if (!strcmp(buf1, "MAXVAL")) {
pnm_get(s, buf1, sizeof(buf1));
maxval = strtol(buf1, NULL, 10);
} else if (!strcmp(buf1, "TUPLETYPE")) {
pnm_get(s, tuple_type, sizeof(tuple_type));
} else if (!strcmp(buf1, "ENDHDR")) {
break;
} else {
return -1;
}
}
/* check that all tags are present */
if (w <= 0 || h <= 0 || maxval <= 0 || depth <= 0 || tuple_type[0] == '\0' || avcodec_check_dimensions(avctx, w, h))
return -1;
avctx->width = w;
avctx->height = h;
if (depth == 1) {
if (maxval == 1)
avctx->pix_fmt = PIX_FMT_MONOWHITE;
else
avctx->pix_fmt = PIX_FMT_GRAY8;
} else if (depth == 3) {
if (maxval < 256) {
avctx->pix_fmt = PIX_FMT_RGB24;
} else {
av_log(avctx, AV_LOG_ERROR, "16-bit components are only supported for grayscale\n");
avctx->pix_fmt = PIX_FMT_NONE;
return -1;
}
} else if (depth == 4) {
avctx->pix_fmt = PIX_FMT_RGB32;
} else {
return -1;
}
return 0;
} else {
return -1;
}
pnm_get(s, buf1, sizeof(buf1));
avctx->width = atoi(buf1);
if (avctx->width <= 0)
return -1;
pnm_get(s, buf1, sizeof(buf1));
avctx->height = atoi(buf1);
if(avcodec_check_dimensions(avctx, avctx->width, avctx->height))
return -1;
if (avctx->pix_fmt != PIX_FMT_MONOWHITE) {
pnm_get(s, buf1, sizeof(buf1));
s->maxval = atoi(buf1);
if (s->maxval >= 256) {
if (avctx->pix_fmt == PIX_FMT_GRAY8) {
avctx->pix_fmt = PIX_FMT_GRAY16BE;
if (s->maxval != 65535)
avctx->pix_fmt = PIX_FMT_GRAY16;
} else {
av_log(avctx, AV_LOG_ERROR, "16-bit components are only supported for grayscale\n");
avctx->pix_fmt = PIX_FMT_NONE;
return -1;
}
}
}
/* more check if YUV420 */
if (avctx->pix_fmt == PIX_FMT_YUV420P) {
if ((avctx->width & 1) != 0)
return -1;
h = (avctx->height * 2);
if ((h % 3) != 0)
return -1;
h /= 3;
avctx->height = h;
}
return 0;
}