72 строки
2.3 KiB
C
72 строки
2.3 KiB
C
/*
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* Copyright (c) 2016, Alliance for Open Media. All rights reserved
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*
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* This source code is subject to the terms of the BSD 2 Clause License and
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* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
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* was not distributed with this source code in the LICENSE file, you can
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* obtain it at www.aomedia.org/license/software. If the Alliance for Open
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* Media Patent License 1.0 was not distributed with this source code in the
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* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
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*/
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#include <string.h>
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#include "aom_dsp/buf_ans.h"
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#include "aom_mem/aom_mem.h"
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#include "aom/internal/aom_codec_internal.h"
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void aom_buf_ans_alloc(struct BufAnsCoder *c,
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struct aom_internal_error_info *error, int size) {
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c->error = error;
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c->size = size;
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assert(c->size > 1);
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AOM_CHECK_MEM_ERROR(error, c->buf, aom_malloc(c->size * sizeof(*c->buf)));
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// Initialize to overfull to trigger the assert in write.
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c->offset = c->size + 1;
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}
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void aom_buf_ans_free(struct BufAnsCoder *c) {
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aom_free(c->buf);
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c->buf = NULL;
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c->size = 0;
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}
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#if !ANS_MAX_SYMBOLS
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void aom_buf_ans_grow(struct BufAnsCoder *c) {
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struct buffered_ans_symbol *new_buf = NULL;
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int new_size = c->size * 2;
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AOM_CHECK_MEM_ERROR(c->error, new_buf,
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aom_malloc(new_size * sizeof(*new_buf)));
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memcpy(new_buf, c->buf, c->size * sizeof(*c->buf));
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aom_free(c->buf);
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c->buf = new_buf;
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c->size = new_size;
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}
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#endif
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void aom_buf_ans_flush(struct BufAnsCoder *const c) {
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int offset;
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#if ANS_MAX_SYMBOLS
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if (c->offset == 0) return;
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#endif
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assert(c->offset > 0);
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offset = c->offset - 1;
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// Code the first symbol such that it brings the state to the smallest normal
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// state from an initial state that would have been a subnormal/refill state.
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if (c->buf[offset].method == ANS_METHOD_RANS) {
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c->ans.state += c->buf[offset].val_start;
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} else {
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c->ans.state += c->buf[offset].val_start ? c->buf[offset].prob : 0;
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}
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for (offset = offset - 1; offset >= 0; --offset) {
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if (c->buf[offset].method == ANS_METHOD_RANS) {
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rans_write(&c->ans, c->buf[offset].val_start, c->buf[offset].prob);
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} else {
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rabs_write(&c->ans, (uint8_t)c->buf[offset].val_start,
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(AnsP8)c->buf[offset].prob);
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}
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}
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c->offset = 0;
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c->output_bytes += ans_write_end(&c->ans);
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}
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