47 lines
1.3 KiB
C
47 lines
1.3 KiB
C
/*
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* Copyright (c) 2013 The WebM project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef VP9_BIT_WRITE_BUFFER_H_
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#define VP9_BIT_WRITE_BUFFER_H_
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#include "vpx/vpx_integer.h"
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struct vp9_write_bit_buffer {
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uint8_t *bit_buffer;
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size_t bit_offset;
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};
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static size_t vp9_rb_bytes_written(struct vp9_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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static void vp9_wb_write_bit(struct vp9_write_bit_buffer *wb, int bit) {
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const int off = 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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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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static void vp9_wb_write_literal(struct vp9_write_bit_buffer *wb,
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int data, int bits) {
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int bit;
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for (bit = bits - 1; bit >= 0; bit--)
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vp9_wb_write_bit(wb, (data >> bit) & 1);
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}
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#endif // VP9_BIT_WRITE_BUFFER_H_
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