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
17size_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
21void 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
34void 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
39void 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