ffmpeg/libavcodec/xbmdec.c

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/*
* XBM image format
*
* Copyright (c) 2012 Paul B Mahol
*
* 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 "internal.h"
static av_cold int xbm_decode_init(AVCodecContext *avctx)
{
avctx->coded_frame = avcodec_alloc_frame();
if (!avctx->coded_frame)
return AVERROR(ENOMEM);
return 0;
}
static int convert(uint8_t x)
{
if (x >= 'a')
x -= 87;
else if (x >= 'A')
x -= 55;
else
x -= '0';
return x;
}
static int xbm_decode_frame(AVCodecContext *avctx, void *data,
int *data_size, AVPacket *avpkt)
{
AVFrame *p = avctx->coded_frame;
const uint8_t *end, *ptr = avpkt->data;
uint8_t *dst;
int ret, linesize, i, j;
end = avpkt->data + avpkt->size;
while (!avctx->width || !avctx->height) {
char name[256];
int number, len;
ptr += strcspn(ptr, "#");
if (sscanf(ptr, "#define %256s %u", name, &number) != 2)
return AVERROR_INVALIDDATA;
len = strlen(name);
if ((len > 6) && !avctx->height && !memcmp(name + len - 7, "_height", 7)) {
avctx->height = number;
} else if ((len > 5) && !avctx->width && !memcmp(name + len - 6, "_width", 6)) {
avctx->width = number;
} else {
return AVERROR_INVALIDDATA;
}
ptr += strcspn(ptr, "\n\r") + 1;
}
avctx->pix_fmt = PIX_FMT_MONOWHITE;
if (p->data[0])
avctx->release_buffer(avctx, p);
p->reference = 0;
if ((ret = avctx->get_buffer(avctx, p)) < 0)
return ret;
linesize = (avctx->width + 7) / 8;
for (i = 0; i < avctx->height; i++) {
dst = p->data[0] + i * p->linesize[0];
for (j = 0; j < linesize; j++) {
uint8_t val;
ptr += strcspn(ptr, "x") + 1;
if (ptr < end && isxdigit(*ptr)) {
val = convert(*ptr);
ptr++;
if (isxdigit(*ptr))
val = (val << 4) + convert(*ptr);
*dst++ = av_reverse[val];
} else {
return AVERROR_INVALIDDATA;
}
}
}
p->key_frame = 1;
p->pict_type = AV_PICTURE_TYPE_I;
*data_size = sizeof(AVFrame);
*(AVFrame *)data = *p;
return avpkt->size;
}
static av_cold int xbm_decode_close(AVCodecContext *avctx)
{
if (avctx->coded_frame->data[0])
avctx->release_buffer(avctx, avctx->coded_frame);
av_freep(&avctx->coded_frame);
return 0;
}
AVCodec ff_xbm_decoder = {
.name = "xbm",
.type = AVMEDIA_TYPE_VIDEO,
.id = CODEC_ID_XBM,
.init = xbm_decode_init,
.close = xbm_decode_close,
.decode = xbm_decode_frame,
.capabilities = CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("XBM (X BitMap) image"),
};