static int IsValidExtendedFormat(const WebPDemuxer* const dmux) {
const int has_fragments = !!(dmux->feature_flags_ & FRAGMENTS_FLAG);
const int has_frames = !!(dmux->feature_flags_ & ANIMATION_FLAG);
const Frame* f;
if (dmux->state_ == WEBP_DEMUX_PARSING_HEADER) return 1;
if (dmux->canvas_width_ <= 0 || dmux->canvas_height_ <= 0) return 0;
if (dmux->loop_count_ < 0) return 0;
if (dmux->state_ == WEBP_DEMUX_DONE && dmux->frames_ == NULL) return 0;
for (f = dmux->frames_; f != NULL; f = f->next_) {
const int cur_frame_set = f->frame_num_;
int frame_count = 0, fragment_count = 0;
// Check frame properties and if the image is composed of fragments that
// each fragment came from a fragment.
for (; f != NULL && f->frame_num_ == cur_frame_set; f = f->next_) {
const ChunkData* const image = f->img_components_;
const ChunkData* const alpha = f->img_components_ + 1;
if (!has_fragments && f->is_fragment_) return 0;
if (!has_frames && f->frame_num_ > 1) return 0;
if (f->complete_) {
if (alpha->size_ == 0 && image->size_ == 0) return 0;
// Ensure alpha precedes image bitstream.
if (alpha->size_ > 0 && alpha->offset_ > image->offset_) {
return 0;
}
if (f->width_ <= 0 || f->height_ <= 0) return 0;
} else {
// There shouldn't be a partial frame in a complete file.
if (dmux->state_ == WEBP_DEMUX_DONE) return 0;
// Ensure alpha precedes image bitstream.
if (alpha->size_ > 0 && image->size_ > 0 &&
alpha->offset_ > image->offset_) {
return 0;
}
// There shouldn't be any frames after an incomplete one.
if (f->next_ != NULL) return 0;
}
if (f->width_ > 0 && f->height_ > 0 &&
!CheckFrameBounds(f, !(has_frames || has_fragments),
dmux->canvas_width_, dmux->canvas_height_)) {
return 0;
}
fragment_count += f->is_fragment_;
++frame_count;
}
if (!has_fragments && frame_count > 1) return 0;
if (fragment_count > 0 && frame_count != fragment_count) return 0;
if (f == NULL) break;
}
return 1;
}
static int IsValidExtendedFormat(const WebPDemuxer* const dmux) {
const int is_animation = !!(dmux->feature_flags_ & ANIMATION_FLAG);
const int is_fragmented = !!(dmux->feature_flags_ & FRAGMENTS_FLAG);
const Frame* f = dmux->frames_;
if (dmux->state_ == WEBP_DEMUX_PARSING_HEADER) return 1;
if (dmux->canvas_width_ <= 0 || dmux->canvas_height_ <= 0) return 0;
if (dmux->loop_count_ < 0) return 0;
if (dmux->state_ == WEBP_DEMUX_DONE && dmux->frames_ == NULL) return 0;
if (is_fragmented) return 0;
while (f != NULL) {
const int cur_frame_set = f->frame_num_;
int frame_count = 0;
// Check frame properties.
for (; f != NULL && f->frame_num_ == cur_frame_set; f = f->next_) {
const ChunkData* const image = f->img_components_;
const ChunkData* const alpha = f->img_components_ + 1;
if (!is_animation && f->frame_num_ > 1) return 0;
if (f->complete_) {
if (alpha->size_ == 0 && image->size_ == 0) return 0;
// Ensure alpha precedes image bitstream.
if (alpha->size_ > 0 && alpha->offset_ > image->offset_) {
return 0;
}
if (f->width_ <= 0 || f->height_ <= 0) return 0;
} else {
// There shouldn't be a partial frame in a complete file.
if (dmux->state_ == WEBP_DEMUX_DONE) return 0;
// Ensure alpha precedes image bitstream.
if (alpha->size_ > 0 && image->size_ > 0 &&
alpha->offset_ > image->offset_) {
return 0;
}
// There shouldn't be any frames after an incomplete one.
if (f->next_ != NULL) return 0;
}
if (f->width_ > 0 && f->height_ > 0 &&
!CheckFrameBounds(f, !is_animation,
dmux->canvas_width_, dmux->canvas_height_)) {
return 0;
}
++frame_count;
}
}
return 1;
}
