| /* |
| * Copyright (c) 2021, Alliance for Open Media. All rights reserved |
| * |
| * This source code is subject to the terms of the BSD 3-Clause Clear License |
| * and the Alliance for Open Media Patent License 1.0. If the BSD 3-Clause Clear |
| * License was not distributed with this source code in the LICENSE file, you |
| * can obtain it at aomedia.org/license/software-license/bsd-3-c-c/. If the |
| * Alliance for Open Media Patent License 1.0 was not distributed with this |
| * source code in the PATENTS file, you can obtain it at |
| * aomedia.org/license/patent-license/. |
| */ |
| |
| #include "aom_dsp/binary_codes_reader.h" |
| #include "aom_dsp/recenter.h" |
| #include "av1/common/common.h" |
| |
| uint16_t aom_read_primitive_quniform_(aom_reader *r, |
| uint16_t n ACCT_STR_PARAM) { |
| if (n <= 1) return 0; |
| const int l = get_msb(n) + 1; |
| const int m = (1 << l) - n; |
| const int v = aom_read_literal(r, l - 1, ACCT_STR_NAME); |
| return v < m ? v : (v << 1) - m + aom_read_bit(r, ACCT_STR_NAME); |
| } |
| |
| // Decode finite subexponential code that for a symbol v in [0, n-1] with |
| // parameter k |
| uint16_t aom_read_primitive_subexpfin_(aom_reader *r, uint16_t n, |
| uint16_t k ACCT_STR_PARAM) { |
| int i = 0; |
| int mk = 0; |
| |
| while (1) { |
| int b = (i ? k + i - 1 : k); |
| int a = (1 << b); |
| |
| if (n <= mk + 3 * a) { |
| return aom_read_primitive_quniform(r, n - mk, ACCT_STR_NAME) + mk; |
| } |
| |
| if (!aom_read_bit(r, ACCT_STR_NAME)) { |
| return aom_read_literal(r, b, ACCT_STR_NAME) + mk; |
| } |
| |
| i = i + 1; |
| mk += a; |
| } |
| |
| assert(0); |
| return 0; |
| } |
| |
| uint16_t aom_read_primitive_refsubexpfin_(aom_reader *r, uint16_t n, uint16_t k, |
| uint16_t ref ACCT_STR_PARAM) { |
| return inv_recenter_finite_nonneg( |
| n, ref, aom_read_primitive_subexpfin(r, n, k, ACCT_STR_NAME)); |
| } |