/src/aom/aom_dsp/binary_codes_reader.c
Line | Count | Source (jump to first uncovered line) |
1 | | /* |
2 | | * Copyright (c) 2017, Alliance for Open Media. All rights reserved. |
3 | | * |
4 | | * This source code is subject to the terms of the BSD 2 Clause License and |
5 | | * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License |
6 | | * was not distributed with this source code in the LICENSE file, you can |
7 | | * obtain it at www.aomedia.org/license/software. If the Alliance for Open |
8 | | * Media Patent License 1.0 was not distributed with this source code in the |
9 | | * PATENTS file, you can obtain it at www.aomedia.org/license/patent. |
10 | | */ |
11 | | |
12 | | #include "aom_dsp/binary_codes_reader.h" |
13 | | #include "aom_dsp/recenter.h" |
14 | | |
15 | | #define read_primitive_quniform(r, n, ACCT_STR_NAME) \ |
16 | 112k | read_primitive_quniform_(r, n ACCT_STR_ARG(ACCT_STR_NAME)) |
17 | | #define read_primitive_subexpfin(r, n, k, ACCT_STR_NAME) \ |
18 | 384k | read_primitive_subexpfin_(r, n, k ACCT_STR_ARG(ACCT_STR_NAME)) |
19 | | |
20 | | static uint16_t read_primitive_quniform_(aom_reader *r, |
21 | 112k | uint16_t n ACCT_STR_PARAM) { |
22 | 112k | if (n <= 1) return 0; |
23 | 112k | const int l = get_msb(n) + 1; |
24 | 112k | const int m = (1 << l) - n; |
25 | 112k | const int v = aom_read_literal(r, l - 1, ACCT_STR_NAME); |
26 | 112k | return v < m ? v : (v << 1) - m + aom_read_bit(r, ACCT_STR_NAME); |
27 | 112k | } |
28 | | |
29 | | // Decode finite subexponential code that for a symbol v in [0, n-1] with |
30 | | // parameter k |
31 | | static uint16_t read_primitive_subexpfin_(aom_reader *r, uint16_t n, |
32 | 384k | uint16_t k ACCT_STR_PARAM) { |
33 | 384k | int i = 0; |
34 | 384k | int mk = 0; |
35 | | |
36 | 686k | while (1) { |
37 | 686k | int b = (i ? k + i - 1 : k); |
38 | 686k | int a = (1 << b); |
39 | | |
40 | 686k | if (n <= mk + 3 * a) { |
41 | 112k | return read_primitive_quniform(r, n - mk, ACCT_STR_NAME) + mk; |
42 | 112k | } |
43 | | |
44 | 574k | if (!aom_read_bit(r, ACCT_STR_NAME)) { |
45 | 272k | return aom_read_literal(r, b, ACCT_STR_NAME) + mk; |
46 | 272k | } |
47 | | |
48 | 301k | i = i + 1; |
49 | 301k | mk += a; |
50 | 301k | } |
51 | | |
52 | 18.4E | assert(0); |
53 | 0 | return 0; |
54 | 18.4E | } |
55 | | |
56 | | uint16_t aom_read_primitive_refsubexpfin_(aom_reader *r, uint16_t n, uint16_t k, |
57 | 384k | uint16_t ref ACCT_STR_PARAM) { |
58 | 384k | return inv_recenter_finite_nonneg( |
59 | 384k | n, ref, read_primitive_subexpfin(r, n, k, ACCT_STR_NAME)); |
60 | 384k | } |