case YY_FOUR_CC()

in iOS/WAStickersThirdParty/YYImageCoder.m [525:534]


                case YY_FOUR_CC('I', 'D', 'A', 'T'): {
                    if (info->apng_shared_insert_index == 0) {
                        info->apng_shared_insert_index = i;
                    }
                    if (first_frame_is_cover) {
                        yy_png_frame_info *frame = info->apng_frames + frame_index;
                        frame->chunk_num++;
                        frame->chunk_size += chunk->length + 12;
                    }
                } break;