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 
vpx_rb_bytes_read(struct vpx_read_bit_buffer * rb)13 size_t vpx_rb_bytes_read(struct vpx_read_bit_buffer *rb) {
14   return (rb->bit_offset + 7) >> 3;
15 }
16 
vpx_rb_read_bit(struct vpx_read_bit_buffer * rb)17 int 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     if (rb->error_handler != NULL) rb->error_handler(rb->error_handler_data);
27     return 0;
28   }
29 }
30 
vpx_rb_read_literal(struct vpx_read_bit_buffer * rb,int bits)31 int 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 
vpx_rb_read_signed_literal(struct vpx_read_bit_buffer * rb,int bits)37 int 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 
vpx_rb_read_inv_signed_literal(struct vpx_read_bit_buffer * rb,int bits)42 int 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