зеркало из https://github.com/mozilla/gecko-dev.git
48 строки
1.6 KiB
C
48 строки
1.6 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 "./aom_config.h"
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#include "./bitreader_buffer.h"
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size_t aom_rb_bytes_read(struct aom_read_bit_buffer *rb) {
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return (rb->bit_offset + 7) >> 3;
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}
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int aom_rb_read_bit(struct aom_read_bit_buffer *rb) {
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const uint32_t off = rb->bit_offset;
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const uint32_t p = off >> 3;
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const int q = 7 - (int)(off & 0x7);
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if (rb->bit_buffer + p < rb->bit_buffer_end) {
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const int bit = (rb->bit_buffer[p] >> q) & 1;
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rb->bit_offset = off + 1;
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return bit;
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} else {
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rb->error_handler(rb->error_handler_data);
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return 0;
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}
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}
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int aom_rb_read_literal(struct aom_read_bit_buffer *rb, int bits) {
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int value = 0, bit;
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for (bit = bits - 1; bit >= 0; bit--) value |= aom_rb_read_bit(rb) << bit;
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return value;
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}
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int aom_rb_read_signed_literal(struct aom_read_bit_buffer *rb, int bits) {
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const int value = aom_rb_read_literal(rb, bits);
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return aom_rb_read_bit(rb) ? -value : value;
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}
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int aom_rb_read_inv_signed_literal(struct aom_read_bit_buffer *rb, int bits) {
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const int nbits = sizeof(unsigned) * 8 - bits - 1;
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const unsigned value = (unsigned)aom_rb_read_literal(rb, bits + 1) << nbits;
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return ((int)value) >> nbits;
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}
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