2 * Copyright (c) 2013 The WebM project authors. All Rights Reserved.
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.
10 #include "vp9/decoder/vp9_read_bit_buffer.h"
12 size_t vp9_rb_bytes_read(struct vp9_read_bit_buffer *rb) {
13 return rb->bit_offset / CHAR_BIT + (rb->bit_offset % CHAR_BIT > 0);
16 int vp9_rb_read_bit(struct vp9_read_bit_buffer *rb) {
17 const size_t off = rb->bit_offset;
18 const size_t p = off / CHAR_BIT;
19 const int q = CHAR_BIT - 1 - (int)off % CHAR_BIT;
20 if (rb->bit_buffer + p >= rb->bit_buffer_end) {
21 rb->error_handler(rb->error_handler_data);
24 const int bit = (rb->bit_buffer[p] & (1 << q)) >> q;
25 rb->bit_offset = off + 1;
30 int vp9_rb_read_literal(struct vp9_read_bit_buffer *rb, int bits) {
32 for (bit = bits - 1; bit >= 0; bit--)
33 value |= vp9_rb_read_bit(rb) << bit;
37 int vp9_rb_read_signed_literal(struct vp9_read_bit_buffer *rb,
39 const int value = vp9_rb_read_literal(rb, bits);
40 return vp9_rb_read_bit(rb) ? -value : value;