62 строки
2.0 KiB
C
62 строки
2.0 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 <limits.h>
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#include <stdlib.h>
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#include "./aom_config.h"
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#include "./bitwriter_buffer.h"
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size_t aom_wb_bytes_written(const struct aom_write_bit_buffer *wb) {
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return wb->bit_offset / CHAR_BIT + (wb->bit_offset % CHAR_BIT > 0);
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}
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void aom_wb_write_bit(struct aom_write_bit_buffer *wb, int bit) {
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const int off = (int)wb->bit_offset;
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const int p = off / CHAR_BIT;
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const int q = CHAR_BIT - 1 - off % CHAR_BIT;
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if (q == CHAR_BIT - 1) {
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// Zero next char and write bit
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wb->bit_buffer[p] = bit << q;
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} else {
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wb->bit_buffer[p] &= ~(1 << q);
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wb->bit_buffer[p] |= bit << q;
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}
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wb->bit_offset = off + 1;
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}
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void aom_wb_overwrite_bit(struct aom_write_bit_buffer *wb, int bit) {
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// Do not zero bytes but overwrite exisiting values
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const int off = (int)wb->bit_offset;
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const int p = off / CHAR_BIT;
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const int q = CHAR_BIT - 1 - off % CHAR_BIT;
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wb->bit_buffer[p] &= ~(1 << q);
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wb->bit_buffer[p] |= bit << q;
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wb->bit_offset = off + 1;
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}
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void aom_wb_write_literal(struct aom_write_bit_buffer *wb, int data, int bits) {
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int bit;
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for (bit = bits - 1; bit >= 0; bit--) aom_wb_write_bit(wb, (data >> bit) & 1);
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}
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void aom_wb_overwrite_literal(struct aom_write_bit_buffer *wb, int data,
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int bits) {
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int bit;
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for (bit = bits - 1; bit >= 0; bit--)
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aom_wb_overwrite_bit(wb, (data >> bit) & 1);
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}
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void aom_wb_write_inv_signed_literal(struct aom_write_bit_buffer *wb, int data,
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int bits) {
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aom_wb_write_literal(wb, data, bits + 1);
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}
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