1 /*
2 * Copyright (c) 2016, 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 <string.h>
13
14 #include "aom_dsp/buf_ans.h"
15 #include "aom_mem/aom_mem.h"
16 #include "aom/internal/aom_codec_internal.h"
17
aom_buf_ans_alloc(struct BufAnsCoder * c,struct aom_internal_error_info * error)18 void aom_buf_ans_alloc(struct BufAnsCoder *c,
19 struct aom_internal_error_info *error) {
20 c->error = error;
21 assert(c->size > 1);
22 AOM_CHECK_MEM_ERROR(error, c->buf, aom_malloc(c->size * sizeof(*c->buf)));
23 // Initialize to overfull to trigger the assert in write.
24 c->offset = c->size + 1;
25 }
26
aom_buf_ans_free(struct BufAnsCoder * c)27 void aom_buf_ans_free(struct BufAnsCoder *c) {
28 aom_free(c->buf);
29 c->buf = NULL;
30 c->size = 0;
31 }
32
33 #if !ANS_MAX_SYMBOLS
aom_buf_ans_grow(struct BufAnsCoder * c)34 void aom_buf_ans_grow(struct BufAnsCoder *c) {
35 struct buffered_ans_symbol *new_buf = NULL;
36 int new_size = c->size * 2;
37 AOM_CHECK_MEM_ERROR(c->error, new_buf,
38 aom_malloc(new_size * sizeof(*new_buf)));
39 memcpy(new_buf, c->buf, c->size * sizeof(*c->buf));
40 aom_free(c->buf);
41 c->buf = new_buf;
42 c->size = new_size;
43 }
44 #endif
45
aom_buf_ans_flush(struct BufAnsCoder * const c)46 void aom_buf_ans_flush(struct BufAnsCoder *const c) {
47 int offset;
48 #if ANS_MAX_SYMBOLS
49 if (c->offset == 0) return;
50 #endif
51 assert(c->offset > 0);
52 offset = c->offset - 1;
53 // Code the first symbol such that it brings the state to the smallest normal
54 // state from an initial state that would have been a subnormal/refill state.
55 if (c->buf[offset].method == ANS_METHOD_RANS) {
56 c->ans.state += c->buf[offset].val_start;
57 } else {
58 c->ans.state += c->buf[offset].val_start ? c->buf[offset].prob : 0;
59 }
60 for (offset = offset - 1; offset >= 0; --offset) {
61 if (c->buf[offset].method == ANS_METHOD_RANS) {
62 rans_write(&c->ans, c->buf[offset].val_start, c->buf[offset].prob);
63 } else {
64 rabs_write(&c->ans, (uint8_t)c->buf[offset].val_start,
65 (AnsP8)c->buf[offset].prob);
66 }
67 }
68 c->offset = 0;
69 c->output_bytes += ans_write_end(&c->ans);
70 }
71