static int jp2_find_codestream(Jpeg2000DecoderContext *s) { uint32_t atom_size, atom, atom_end; int search_range = 10; while (search_range && bytestream2_get_bytes_left(&s->g) >= 8) { atom_size = bytestream2_get_be32u(&s->g); atom = bytestream2_get_be32u(&s->g); atom_end = bytestream2_tell(&s->g) + atom_size - 8; if (atom == JP2_CODESTREAM) return 1; if (bytestream2_get_bytes_left(&s->g) < atom_size || atom_end < atom_size) return 0; if (atom == JP2_HEADER && atom_size >= 16) { uint32_t atom2_size, atom2, atom2_end; do { atom2_size = bytestream2_get_be32u(&s->g); atom2 = bytestream2_get_be32u(&s->g); atom2_end = bytestream2_tell(&s->g) + atom2_size - 8; if (atom2_size < 8 || atom2_end > atom_end || atom2_end < atom2_size) break; atom2_size -= 8; if (atom2 == JP2_CODESTREAM) { return 1; } else if (atom2 == MKBETAG('c','o','l','r') && atom2_size >= 7) { int method = bytestream2_get_byteu(&s->g); bytestream2_skipu(&s->g, 2); if (method == 1) { s->colour_space = bytestream2_get_be32u(&s->g); } else if (atom2 == MKBETAG('p','c','l','r') && atom2_size >= 6) { int i, size, colour_count, colour_channels, colour_depth[3]; uint32_t r, g, b; colour_count = bytestream2_get_be16u(&s->g); colour_channels = bytestream2_get_byteu(&s->g); // FIXME: Do not ignore channel_sign colour_depth[0] = (bytestream2_get_byteu(&s->g) & 0x7f) + 1; colour_depth[1] = (bytestream2_get_byteu(&s->g) & 0x7f) + 1; colour_depth[2] = (bytestream2_get_byteu(&s->g) & 0x7f) + 1; size = (colour_depth[0] + 7 >> 3) * colour_count + (colour_depth[1] + 7 >> 3) * colour_count + (colour_depth[2] + 7 >> 3) * colour_count; if (colour_count > 256 || colour_channels != 3 || colour_depth[0] > 16 || colour_depth[1] > 16 || colour_depth[2] > 16 || atom2_size < size) { avpriv_request_sample(s->avctx, "Unknown palette"); s->pal8 = 1; for (i = 0; i < colour_count; i++) { if (colour_depth[0] <= 8) { r = bytestream2_get_byteu(&s->g) << 8 - colour_depth[0]; r |= r >> colour_depth[0]; } else { r = bytestream2_get_be16u(&s->g) >> colour_depth[0] - 8; if (colour_depth[1] <= 8) { g = bytestream2_get_byteu(&s->g) << 8 - colour_depth[1]; r |= r >> colour_depth[1]; } else { g = bytestream2_get_be16u(&s->g) >> colour_depth[1] - 8; if (colour_depth[2] <= 8) { b = bytestream2_get_byteu(&s->g) << 8 - colour_depth[2]; r |= r >> colour_depth[2]; } else { b = bytestream2_get_be16u(&s->g) >> colour_depth[2] - 8; s->palette[i] = 0xffu << 24 | r << 16 | g << 8 | b; } else if (atom2 == MKBETAG('c','d','e','f') && atom2_size >= 2) { int n = bytestream2_get_be16u(&s->g); for (; n>0; n--) { int cn = bytestream2_get_be16(&s->g); int av_unused typ = bytestream2_get_be16(&s->g); int asoc = bytestream2_get_be16(&s->g); if (cn < 4 && asoc < 4) s->cdef[cn] = asoc; } else if (atom2 == MKBETAG('r','e','s',' ') && atom2_size >= 18) { int64_t vnum, vden, hnum, hden, vexp, hexp; uint32_t resx; bytestream2_skip(&s->g, 4); resx = bytestream2_get_be32u(&s->g); if (resx != MKBETAG('r','e','s','c') && resx != MKBETAG('r','e','s','d')) { vnum = bytestream2_get_be16u(&s->g); vden = bytestream2_get_be16u(&s->g); hnum = bytestream2_get_be16u(&s->g); hden = bytestream2_get_be16u(&s->g); vexp = bytestream2_get_byteu(&s->g); hexp = bytestream2_get_byteu(&s->g); if (vexp > hexp) { vexp -= hexp; hexp = 0; } else { hexp -= vexp; vexp = 0; if ( INT64_MAX / (hnum * vden) > pow(10, hexp) && INT64_MAX / (vnum * hden) > pow(10, vexp)) av_reduce(&s->sar.den, &s->sar.num, hnum * vden * pow(10, hexp), vnum * hden * pow(10, vexp), INT32_MAX); } while (atom_end - atom2_end >= 8); } else { search_range--; bytestream2_seek(&s->g, atom_end, SEEK_SET); return 0;