static int gif_read_header1(GifState *s)
{
uint8_t sig[6];
int v, n;
int background_color_index;
if (bytestream2_get_bytes_left(&s->gb) < 13)
return AVERROR_INVALIDDATA;
/* read gif signature */
bytestream2_get_bufferu(&s->gb, sig, 6);
if (memcmp(sig, gif87a_sig, 6) != 0 &&
memcmp(sig, gif89a_sig, 6) != 0)
return AVERROR_INVALIDDATA;
/* read screen header */
s->transparent_color_index = -1;
s->screen_width = bytestream2_get_le16u(&s->gb);
s->screen_height = bytestream2_get_le16u(&s->gb);
if( (unsigned)s->screen_width > 32767
|| (unsigned)s->screen_height > 32767){
av_log(s->avctx, AV_LOG_ERROR, "picture size too large\n");
return AVERROR_INVALIDDATA;
}
av_fast_malloc(&s->idx_line, &s->idx_line_size, s->screen_width);
if (!s->idx_line)
return AVERROR(ENOMEM);
v = bytestream2_get_byteu(&s->gb);
s->color_resolution = ((v & 0x70) >> 4) + 1;
s->has_global_palette = (v & 0x80);
s->bits_per_pixel = (v & 0x07) + 1;
background_color_index = bytestream2_get_byteu(&s->gb);
n = bytestream2_get_byteu(&s->gb);
if (n) {
s->avctx->sample_aspect_ratio.num = n + 15;
s->avctx->sample_aspect_ratio.den = 64;
}
av_dlog(s->avctx, "screen_w=%d screen_h=%d bpp=%d global_palette=%d\n",
s->screen_width, s->screen_height, s->bits_per_pixel,
s->has_global_palette);
if (s->has_global_palette) {
s->background_color_index = background_color_index;
n = 1 << s->bits_per_pixel;
if (bytestream2_get_bytes_left(&s->gb) < n * 3)
return AVERROR_INVALIDDATA;
gif_read_palette(s, s->global_palette, n);
s->bg_color = s->global_palette[s->background_color_index];
} else
s->background_color_index = -1;
return 0;
}
static int gif_read_header1(GifState *s)
{
uint8_t sig[6];
int v, n;
int background_color_index;
if (bytestream2_get_bytes_left(&s->gb) < 13)
return AVERROR_INVALIDDATA;
/* read gif signature */
bytestream2_get_bufferu(&s->gb, sig, 6);
if (memcmp(sig, gif87a_sig, 6) &&
memcmp(sig, gif89a_sig, 6))
return AVERROR_INVALIDDATA;
/* read screen header */
s->transparent_color_index = -1;
s->screen_width = bytestream2_get_le16u(&s->gb);
s->screen_height = bytestream2_get_le16u(&s->gb);
v = bytestream2_get_byteu(&s->gb);
s->color_resolution = ((v & 0x70) >> 4) + 1;
s->has_global_palette = (v & 0x80);
s->bits_per_pixel = (v & 0x07) + 1;
background_color_index = bytestream2_get_byteu(&s->gb);
n = bytestream2_get_byteu(&s->gb);
if (n) {
s->avctx->sample_aspect_ratio.num = n + 15;
s->avctx->sample_aspect_ratio.den = 64;
}
ff_dlog(s->avctx, "screen_w=%d screen_h=%d bpp=%d global_palette=%d\n",
s->screen_width, s->screen_height, s->bits_per_pixel,
s->has_global_palette);
if (s->has_global_palette) {
s->background_color_index = background_color_index;
n = 1 << s->bits_per_pixel;
if (bytestream2_get_bytes_left(&s->gb) < n * 3)
return AVERROR_INVALIDDATA;
gif_read_palette(s, s->global_palette, n);
s->bg_color = s->global_palette[s->background_color_index];
} else
s->background_color_index = -1;
return 0;
}
static int gif_read_image(GifState *s, AVFrame *frame)
{
int left, top, width, height, bits_per_pixel, code_size, flags, pw;
int is_interleaved, has_local_palette, y, pass, y1, linesize, pal_size;
uint32_t *ptr, *pal, *px, *pr, *ptr1;
int ret;
uint8_t *idx;
/* At least 9 bytes of Image Descriptor. */
if (bytestream2_get_bytes_left(&s->gb) < 9)
return AVERROR_INVALIDDATA;
left = bytestream2_get_le16u(&s->gb);
top = bytestream2_get_le16u(&s->gb);
width = bytestream2_get_le16u(&s->gb);
height = bytestream2_get_le16u(&s->gb);
flags = bytestream2_get_byteu(&s->gb);
is_interleaved = flags & 0x40;
has_local_palette = flags & 0x80;
bits_per_pixel = (flags & 0x07) + 1;
av_dlog(s->avctx, "image x=%d y=%d w=%d h=%d\n", left, top, width, height);
if (has_local_palette) {
pal_size = 1 << bits_per_pixel;
if (bytestream2_get_bytes_left(&s->gb) < pal_size * 3)
return AVERROR_INVALIDDATA;
gif_read_palette(s, s->local_palette, pal_size);
pal = s->local_palette;
} else {
if (!s->has_global_palette) {
av_log(s->avctx, AV_LOG_ERROR, "picture doesn't have either global or local palette.\n");
return AVERROR_INVALIDDATA;
}
pal = s->global_palette;
}
if (s->keyframe) {
if (s->transparent_color_index == -1 && s->has_global_palette) {
/* transparency wasn't set before the first frame, fill with background color */
gif_fill(frame, s->bg_color);
} else {
/* otherwise fill with transparent color.
* this is necessary since by default picture filled with 0x80808080. */
gif_fill(frame, s->trans_color);
}
}
/* verify that all the image is inside the screen dimensions */
if (!width || width > s->screen_width || left >= s->screen_width) {
av_log(s->avctx, AV_LOG_ERROR, "Invalid image width.\n");
return AVERROR_INVALIDDATA;
}
if (!height || height > s->screen_height || top >= s->screen_height) {
av_log(s->avctx, AV_LOG_ERROR, "Invalid image height.\n");
return AVERROR_INVALIDDATA;
}
if (left + width > s->screen_width) {
/* width must be kept around to avoid lzw vs line desync */
pw = s->screen_width - left;
av_log(s->avctx, AV_LOG_WARNING, "Image too wide by %d, truncating.\n",
left + width - s->screen_width);
} else {
pw = width;
}
if (top + height > s->screen_height) {
/* we don't care about the extra invisible lines */
av_log(s->avctx, AV_LOG_WARNING, "Image too high by %d, truncating.\n",
top + height - s->screen_height);
height = s->screen_height - top;
}
/* process disposal method */
if (s->gce_prev_disposal == GCE_DISPOSAL_BACKGROUND) {
gif_fill_rect(frame, s->stored_bg_color, s->gce_l, s->gce_t, s->gce_w, s->gce_h);
} else if (s->gce_prev_disposal == GCE_DISPOSAL_RESTORE) {
gif_copy_img_rect(s->stored_img, (uint32_t *)frame->data[0],
frame->linesize[0] / sizeof(uint32_t), s->gce_l, s->gce_t, s->gce_w, s->gce_h);
}
s->gce_prev_disposal = s->gce_disposal;
if (s->gce_disposal != GCE_DISPOSAL_NONE) {
s->gce_l = left; s->gce_t = top;
s->gce_w = pw; s->gce_h = height;
if (s->gce_disposal == GCE_DISPOSAL_BACKGROUND) {
if (s->transparent_color_index >= 0)
s->stored_bg_color = s->trans_color;
else
s->stored_bg_color = s->bg_color;
} else if (s->gce_disposal == GCE_DISPOSAL_RESTORE) {
av_fast_malloc(&s->stored_img, &s->stored_img_size, frame->linesize[0] * frame->height);
if (!s->stored_img)
return AVERROR(ENOMEM);
gif_copy_img_rect((uint32_t *)frame->data[0], s->stored_img,
frame->linesize[0] / sizeof(uint32_t), left, top, pw, height);
}
}
/* Expect at least 2 bytes: 1 for lzw code size and 1 for block size. */
if (bytestream2_get_bytes_left(&s->gb) < 2)
return AVERROR_INVALIDDATA;
/* now get the image data */
code_size = bytestream2_get_byteu(&s->gb);
if ((ret = ff_lzw_decode_init(s->lzw, code_size, s->gb.buffer,
bytestream2_get_bytes_left(&s->gb), FF_LZW_GIF)) < 0) {
av_log(s->avctx, AV_LOG_ERROR, "LZW init failed\n");
return ret;
}
/* read all the image */
linesize = frame->linesize[0] / sizeof(uint32_t);
ptr1 = (uint32_t *)frame->data[0] + top * linesize + left;
ptr = ptr1;
pass = 0;
y1 = 0;
for (y = 0; y < height; y++) {
int count = ff_lzw_decode(s->lzw, s->idx_line, width);
if (count != width) {
if (count)
av_log(s->avctx, AV_LOG_ERROR, "LZW decode failed\n");
goto decode_tail;
}
pr = ptr + pw;
for (px = ptr, idx = s->idx_line; px < pr; px++, idx++) {
if (*idx != s->transparent_color_index)
*px = pal[*idx];
}
if (is_interleaved) {
switch(pass) {
default:
case 0:
case 1:
y1 += 8;
ptr += linesize * 8;
if (y1 >= height) {
y1 = pass ? 2 : 4;
ptr = ptr1 + linesize * y1;
pass++;
}
break;
case 2:
y1 += 4;
ptr += linesize * 4;
if (y1 >= height) {
y1 = 1;
ptr = ptr1 + linesize;
pass++;
}
break;
case 3:
y1 += 2;
ptr += linesize * 2;
break;
}
} else {
ptr += linesize;
}
}
decode_tail:
/* read the garbage data until end marker is found */
ff_lzw_decode_tail(s->lzw);
/* Graphic Control Extension's scope is single frame.
* Remove its influence. */
s->transparent_color_index = -1;
s->gce_disposal = GCE_DISPOSAL_NONE;
return 0;
}
static int gif_read_image(GifState *s)
{
int left, top, width, height, bits_per_pixel, code_size, flags;
int is_interleaved, has_local_palette, y, pass, y1, linesize, pal_size;
uint32_t *ptr, *pal, *px, *pr, *ptr1;
int ret;
uint8_t *idx;
/* At least 9 bytes of Image Descriptor. */
if (s->bytestream_end < s->bytestream + 9)
return AVERROR_INVALIDDATA;
left = bytestream_get_le16(&s->bytestream);
top = bytestream_get_le16(&s->bytestream);
width = bytestream_get_le16(&s->bytestream);
height = bytestream_get_le16(&s->bytestream);
flags = bytestream_get_byte(&s->bytestream);
is_interleaved = flags & 0x40;
has_local_palette = flags & 0x80;
bits_per_pixel = (flags & 0x07) + 1;
av_dlog(s->avctx, "image x=%d y=%d w=%d h=%d\n", left, top, width, height);
if (has_local_palette) {
pal_size = 1 << bits_per_pixel;
if (s->bytestream_end < s->bytestream + pal_size * 3)
return AVERROR_INVALIDDATA;
gif_read_palette(&s->bytestream, s->local_palette, pal_size);
pal = s->local_palette;
} else {
if (!s->has_global_palette) {
av_log(s->avctx, AV_LOG_FATAL, "picture doesn't have either global or local palette.\n");
return AVERROR_INVALIDDATA;
}
pal = s->global_palette;
}
if (s->keyframe) {
if (s->transparent_color_index == -1 && s->has_global_palette) {
/* transparency wasn't set before the first frame, fill with background color */
gif_fill(&s->picture, s->bg_color);
} else {
/* otherwise fill with transparent color.
* this is necessary since by default picture filled with 0x80808080. */
gif_fill(&s->picture, s->trans_color);
}
}
/* verify that all the image is inside the screen dimensions */
if (left + width > s->screen_width ||
top + height > s->screen_height)
return AVERROR(EINVAL);
/* process disposal method */
if (s->gce_prev_disposal == GCE_DISPOSAL_BACKGROUND) {
gif_fill_rect(&s->picture, s->stored_bg_color, s->gce_l, s->gce_t, s->gce_w, s->gce_h);
} else if (s->gce_prev_disposal == GCE_DISPOSAL_RESTORE) {
gif_copy_img_rect(s->stored_img, (uint32_t *)s->picture.data[0],
s->picture.linesize[0] / sizeof(uint32_t), s->gce_l, s->gce_t, s->gce_w, s->gce_h);
}
s->gce_prev_disposal = s->gce_disposal;
if (s->gce_disposal != GCE_DISPOSAL_NONE) {
s->gce_l = left; s->gce_t = top;
s->gce_w = width; s->gce_h = height;
if (s->gce_disposal == GCE_DISPOSAL_BACKGROUND) {
if (s->background_color_index == s->transparent_color_index)
s->stored_bg_color = s->trans_color;
else
s->stored_bg_color = s->bg_color;
} else if (s->gce_disposal == GCE_DISPOSAL_RESTORE) {
av_fast_malloc(&s->stored_img, &s->stored_img_size, s->picture.linesize[0] * s->picture.height);
if (!s->stored_img)
return AVERROR(ENOMEM);
gif_copy_img_rect((uint32_t *)s->picture.data[0], s->stored_img,
s->picture.linesize[0] / sizeof(uint32_t), left, top, width, height);
}
}
/* Expect at least 2 bytes: 1 for lzw code size and 1 for block size. */
if (s->bytestream_end < s->bytestream + 2)
return AVERROR_INVALIDDATA;
/* now get the image data */
code_size = bytestream_get_byte(&s->bytestream);
if ((ret = ff_lzw_decode_init(s->lzw, code_size, s->bytestream,
s->bytestream_end - s->bytestream, FF_LZW_GIF)) < 0) {
av_log(s->avctx, AV_LOG_ERROR, "LZW init failed\n");
return ret;
}
/* read all the image */
linesize = s->picture.linesize[0] / sizeof(uint32_t);
ptr1 = (uint32_t *)s->picture.data[0] + top * linesize + left;
ptr = ptr1;
pass = 0;
y1 = 0;
for (y = 0; y < height; y++) {
if (ff_lzw_decode(s->lzw, s->idx_line, width) == 0)
goto decode_tail;
pr = ptr + width;
for (px = ptr, idx = s->idx_line; px < pr; px++, idx++) {
if (*idx != s->transparent_color_index)
*px = pal[*idx];
}
if (is_interleaved) {
switch(pass) {
default:
case 0:
case 1:
y1 += 8;
ptr += linesize * 8;
if (y1 >= height) {
y1 = pass ? 2 : 4;
ptr = ptr1 + linesize * y1;
pass++;
}
break;
case 2:
y1 += 4;
ptr += linesize * 4;
if (y1 >= height) {
y1 = 1;
ptr = ptr1 + linesize;
pass++;
}
break;
case 3:
y1 += 2;
ptr += linesize * 2;
break;
}
} else {
ptr += linesize;
}
}
decode_tail:
/* read the garbage data until end marker is found */
ff_lzw_decode_tail(s->lzw);
s->bytestream = ff_lzw_cur_ptr(s->lzw);
/* Graphic Control Extension's scope is single frame.
* Remove its influence. */
s->transparent_color_index = -1;
s->gce_disposal = GCE_DISPOSAL_NONE;
return 0;
}