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#include "./vpx_config.h"
11#include "./bitreader_buffer.h"
12
13size_t vpx_rb_bytes_read(struct vpx_read_bit_buffer *rb) {
14  return (rb->bit_offset + 7) >> 3;
15}
16
17int vpx_rb_read_bit(struct vpx_read_bit_buffer *rb) {
18  const size_t off = rb->bit_offset;
19  const size_t p = off >> 3;
20  const int q = 7 - (int)(off & 0x7);
21  if (rb->bit_buffer + p < rb->bit_buffer_end) {
22    const int bit = (rb->bit_buffer[p] >> q) & 1;
23    rb->bit_offset = off + 1;
24    return bit;
25  } else {
26    rb->error_handler(rb->error_handler_data);
27    return 0;
28  }
29}
30
31int vpx_rb_read_literal(struct vpx_read_bit_buffer *rb, int bits) {
32  int value = 0, bit;
33  for (bit = bits - 1; bit >= 0; bit--) value |= vpx_rb_read_bit(rb) << bit;
34  return value;
35}
36
37int vpx_rb_read_signed_literal(struct vpx_read_bit_buffer *rb, int bits) {
38  const int value = vpx_rb_read_literal(rb, bits);
39  return vpx_rb_read_bit(rb) ? -value : value;
40}
41
42int vpx_rb_read_inv_signed_literal(struct vpx_read_bit_buffer *rb, int bits) {
43  return vpx_rb_read_signed_literal(rb, bits);
44}
45