static int mjpeg_decode_dht(MJpegDecodeContext *s) { int len, index, i, class, n, v, code_max; uint8_t bits_table[17]; uint8_t val_table[256]; len = get_bits(&s->gb, 16) - 2; while (len > 0) { if (len < 17) return -1; class = get_bits(&s->gb, 4); if (class >= 2) return -1; index = get_bits(&s->gb, 4); if (index >= 4) return -1; n = 0; for(i=1;i<=16;i++) { bits_table[i] = get_bits(&s->gb, 8); n += bits_table[i]; } len -= 17; if (len < n || n > 256) return -1; code_max = 0; for(i=0;i<n;i++) { v = get_bits(&s->gb, 8); if (v > code_max) code_max = v; val_table[i] = v; } len -= n; /* build VLC and flush previous vlc if present */ free_vlc(&s->vlcs[class][index]); dprintf("class=%d index=%d nb_codes=%d\n", class, index, code_max + 1); if(build_vlc(&s->vlcs[class][index], bits_table, val_table, code_max + 1) < 0){ return -1; } } return 0; }