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author | Vitaliy E Sugrobov <vsugrob@hotmail.com> | 2012-11-30 12:58:52 +0400 |
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committer | Paul B Mahol <onemda@gmail.com> | 2012-11-30 14:33:58 +0000 |
commit | c5fe41c7680c0492abd1928e3d7072b2d9c5afbe (patch) | |
tree | ae8ab5c513937c84772e8cac9ca88beaa0b92025 /libavcodec/gifdec.c | |
parent | 034a1afbd85ee18c1b7f3b9be59371173d421c6b (diff) | |
download | ffmpeg-c5fe41c7680c0492abd1928e3d7072b2d9c5afbe.tar.gz |
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>
Diffstat (limited to 'libavcodec/gifdec.c')
-rw-r--r-- | libavcodec/gifdec.c | 40 |
1 files changed, 24 insertions, 16 deletions
diff --git a/libavcodec/gifdec.c b/libavcodec/gifdec.c index 2a61090ef9..91139e195b 100644 --- a/libavcodec/gifdec.c +++ b/libavcodec/gifdec.c @@ -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; } |