1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 // Note: ported from Chromium commit head: 2de6929
5 
6 #include "bit_reader.h"
7 
8 namespace media {
9 
10 BitReader::BitReader(const uint8_t* data, int size)
11     : initial_size_(size),
12       data_(data),
13       bytes_left_(size),
14       bit_reader_core_(this) {
15   DCHECK(data != NULL);
16   DCHECK_GE(size, 0);
17 }
18 
19 BitReader::~BitReader() = default;
20 
21 bool BitReader::ReadString(int num_bits, std::string* str) {
22   DCHECK_EQ(num_bits % 8, 0);
23   DCHECK_GT(num_bits, 0);
24   DCHECK(str);
25   int num_bytes = num_bits / 8;
26   str->resize(num_bytes);
27   char* ptr = &str->front();
28   while (num_bytes--) {
29     if (!ReadBits(8, ptr++))
30       return false;
31   }
32   return true;
33 }
34 
35 int BitReader::GetBytes(int max_nbytes, const uint8_t** out) {
36   DCHECK_GE(max_nbytes, 0);
37   DCHECK(out);
38 
39   int nbytes = max_nbytes;
40   if (nbytes > bytes_left_)
41     nbytes = bytes_left_;
42 
43   *out = data_;
44   data_ += nbytes;
45   bytes_left_ -= nbytes;
46   return nbytes;
47 }
48 
49 }  // namespace media
50