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 <stdlib.h>
13
14 #include "./vpx_config.h"
15 #include "./bitwriter_buffer.h"
16
vpx_wb_bytes_written(const struct vpx_write_bit_buffer * wb)17 size_t vpx_wb_bytes_written(const struct vpx_write_bit_buffer *wb) {
18 return wb->bit_offset / CHAR_BIT + (wb->bit_offset % CHAR_BIT > 0);
19 }
20
vpx_wb_write_bit(struct vpx_write_bit_buffer * wb,int bit)21 void vpx_wb_write_bit(struct vpx_write_bit_buffer *wb, int bit) {
22 const int off = (int)wb->bit_offset;
23 const int p = off / CHAR_BIT;
24 const int q = CHAR_BIT - 1 - off % CHAR_BIT;
25 if (q == CHAR_BIT - 1) {
26 wb->bit_buffer[p] = bit << q;
27 } else {
28 wb->bit_buffer[p] &= ~(1 << q);
29 wb->bit_buffer[p] |= bit << q;
30 }
31 wb->bit_offset = off + 1;
32 }
33
vpx_wb_write_literal(struct vpx_write_bit_buffer * wb,int data,int bits)34 void vpx_wb_write_literal(struct vpx_write_bit_buffer *wb, int data, int bits) {
35 int bit;
36 for (bit = bits - 1; bit >= 0; bit--) vpx_wb_write_bit(wb, (data >> bit) & 1);
37 }
38
vpx_wb_write_inv_signed_literal(struct vpx_write_bit_buffer * wb,int data,int bits)39 void vpx_wb_write_inv_signed_literal(struct vpx_write_bit_buffer *wb, int data,
40 int bits) {
41 vpx_wb_write_literal(wb, abs(data), bits);
42 vpx_wb_write_bit(wb, data < 0);
43 }
44