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ffmpeg
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Add meaningful error codes and constants. 

Replace literals with named constants in several pieces of code
like 'return -1' and 'case 0xab'.
Change the way decoder handles absence of image data in a file:
notify gif_decode_frame() caller with got_picture set to zero
instead of returning -1.

Signed-off-by: Vitaliy E Sugrobov <vsugrob@hotmail.com>
This commit is contained in:
Vitaliy E Sugrobov 2012-11-30 12:58:52 +04:00 committed by Paul B Mahol
parent 034a1afbd8
commit c5fe41c768
1 changed files with 24 additions and 16 deletions
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40
libavcodec/gifdec.c
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@ -31,6 +31,10 @@
#define GCE_DISPOSAL_INPLACE 1
#define GCE_DISPOSAL_BACKGROUND 2
#define GCE_DISPOSAL_RESTORE 3
#define GIF_TRAILER 0x3b
#define GIF_EXTENSION_INTRODUCER 0x21
#define GIF_IMAGE_SEPARATOR 0x2c
#define GIF_GCE_EXT_LABEL 0xf9
typedef struct GifState {
AVFrame picture;
@ -170,7 +174,7 @@ static int gif_read_extension(GifState *s)
av_dlog(s->avctx, "ext_code=0x%x len=%d\n", ext_code, ext_len);
switch(ext_code) {
case 0xf9:
case GIF_GCE_EXT_LABEL:
if (ext_len != 4)
goto discard_ext;
s->transparent_color_index = -1;
@ -248,28 +252,32 @@ static int gif_read_header1(GifState *s)
return 0;
}
static int gif_parse_next_image(GifState *s)
static int gif_parse_next_image(GifState *s, int *got_picture)
{
int ret;
*got_picture = sizeof(AVPicture);
while (s->bytestream < s->bytestream_end) {
int code = bytestream_get_byte(&s->bytestream);
av_dlog(s->avctx, "code=%02x '%c'\n", code, code);
switch (code) {
case ',':
case GIF_IMAGE_SEPARATOR:
return gif_read_image(s);
case '!':
if (gif_read_extension(s) < 0)
return -1;
case GIF_EXTENSION_INTRODUCER:
if ((ret = gif_read_extension(s)) < 0)
return ret;
break;
case ';':
case GIF_TRAILER:
/* end of image */
*got_picture = 0;
return 0;
default:
/* error or erroneous EOF */
return -1;
/* erroneous block label */
return AVERROR_INVALIDDATA;
}
}
return -1;
return AVERROR_EOF;
}
static av_cold int gif_decode_init(AVCodecContext *avctx)
@ -285,7 +293,7 @@ static av_cold int gif_decode_init(AVCodecContext *avctx)
return 0;
}
static int gif_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt)
static int gif_decode_frame(AVCodecContext *avctx, void *data, int *got_picture, AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
@ -299,8 +307,8 @@ static int gif_decode_frame(AVCodecContext *avctx, void *data, int *data_size, A
return ret;
avctx->pix_fmt = AV_PIX_FMT_PAL8;
if (av_image_check_size(s->screen_width, s->screen_height, 0, avctx))
return -1;
if ((ret = av_image_check_size(s->screen_width, s->screen_height, 0, avctx)) < 0)
return ret;
avcodec_set_dimensions(avctx, s->screen_width, s->screen_height);
if (s->picture.data[0])
@ -310,12 +318,12 @@ static int gif_decode_frame(AVCodecContext *avctx, void *data, int *data_size, A
return ret;
}
s->image_palette = (uint32_t *)s->picture.data[1];
ret = gif_parse_next_image(s);
ret = gif_parse_next_image(s, got_picture);
if (ret < 0)
return ret;
else if (*got_picture)
*picture = s->picture;
*picture = s->picture;
*data_size = sizeof(AVPicture);
return s->bytestream - buf;
}