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1 /*
2  *  Copyright (c) 2013 The WebM project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #include <limits.h>
12 #include "vp9/encoder/vp9_write_bit_buffer.h"
13 
vp9_wb_bytes_written(const struct vp9_write_bit_buffer * wb)14 size_t vp9_wb_bytes_written(const struct vp9_write_bit_buffer *wb) {
15   return wb->bit_offset / CHAR_BIT + (wb->bit_offset % CHAR_BIT > 0);
16 }
17 
vp9_wb_write_bit(struct vp9_write_bit_buffer * wb,int bit)18 void vp9_wb_write_bit(struct vp9_write_bit_buffer *wb, int bit) {
19   const int off = (int)wb->bit_offset;
20   const int p = off / CHAR_BIT;
21   const int q = CHAR_BIT - 1 - off % CHAR_BIT;
22   if (q == CHAR_BIT -1) {
23     wb->bit_buffer[p] = bit << q;
24   } else {
25     wb->bit_buffer[p] &= ~(1 << q);
26     wb->bit_buffer[p] |= bit << q;
27   }
28   wb->bit_offset = off + 1;
29 }
30 
vp9_wb_write_literal(struct vp9_write_bit_buffer * wb,int data,int bits)31 void vp9_wb_write_literal(struct vp9_write_bit_buffer *wb, int data, int bits) {
32   int bit;
33   for (bit = bits - 1; bit >= 0; bit--)
34     vp9_wb_write_bit(wb, (data >> bit) & 1);
35 }
36