void decode_ac_coefficients(const struct huffman_table* tbl, struct bit_source* bits, int16_t* coeff)
{
+ possibly_refill(bits, DEHUF_AC_TABLE_BITS);
for (unsigned i = 0; i < DCTSIZE2 - 1; ) {
- possibly_refill(bits, DEHUF_AC_TABLE_BITS);
unsigned lookup = peek_bits(bits, DEHUF_AC_TABLE_BITS);
int code = tbl->ac_table_codes[lookup];
+ unsigned length = tbl->ac_table_length[lookup];
+ unsigned r = tbl->ac_table_skip[lookup];
if (__builtin_expect(code == AC_DEHUF_SLOW_PATH, 0)) {
unsigned rs = read_huffman_symbol_no_refill(tbl, bits);
- unsigned r = rs >> 4;
- unsigned s = rs & 0xf;
- i += r + 1;
- possibly_refill(bits, s);
-
if (rs == 0x00) {
- assert(code == AC_DEHUF_SLOW_PATH || code == AC_END_OF_BLOCK);
/* end of block */
break;
}
- if (rs == 0xf0) {
- assert(code == AC_DEHUF_SLOW_PATH || code == AC_SIXTEEN_ZEROS);
- /* 16 zero coefficients */
- continue;
- }
+ unsigned r = rs >> 4;
+ unsigned s = rs & 0xf;
+ i += r + 1;
+ possibly_refill(bits, s);
coeff[unzigzag[i]] = extend(read_bits(bits, s), s);
+ possibly_refill(bits, DEHUF_AC_TABLE_BITS);
} else {
- unsigned length = tbl->ac_table_length[lookup];
- int r = tbl->ac_table_skip[lookup];
- assert(r >= 1);
- i += r;
assert(bits->bits_available >= length);
read_bits(bits, length);
- if (code == AC_END_OF_BLOCK) {
- break;
- }
- if (code == AC_SIXTEEN_ZEROS) {
- continue;
- }
+ possibly_refill(bits, DEHUF_AC_TABLE_BITS);
+
+ assert(r >= 1);
+ i += r;
coeff[unzigzag[i]] = code;
}
}