1 // Copyright 2014 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
5 #include "net/spdy/spdy_prefixed_buffer_reader.h"
6
7 #include "base/logging.h"
8
9 namespace net {
10
SpdyPrefixedBufferReader(const char * prefix,size_t prefix_length,const char * suffix,size_t suffix_length)11 SpdyPrefixedBufferReader::SpdyPrefixedBufferReader(
12 const char* prefix,
13 size_t prefix_length,
14 const char* suffix,
15 size_t suffix_length)
16 : prefix_(prefix),
17 suffix_(suffix),
18 prefix_length_(prefix_length),
19 suffix_length_(suffix_length) {}
20
Available()21 size_t SpdyPrefixedBufferReader::Available() {
22 return prefix_length_ + suffix_length_;
23 }
24
ReadN(size_t count,char * out)25 bool SpdyPrefixedBufferReader::ReadN(size_t count, char* out) {
26 if (Available() < count)
27 return false;
28
29 if (prefix_length_ >= count) {
30 // Read is fully satisfied by the prefix.
31 std::copy(prefix_, prefix_ + count, out);
32 prefix_ += count;
33 prefix_length_ -= count;
34 return true;
35 } else if (prefix_length_ != 0) {
36 // Read is partially satisfied by the prefix.
37 out = std::copy(prefix_, prefix_ + prefix_length_, out);
38 count -= prefix_length_;
39 prefix_length_ = 0;
40 // Fallthrough to suffix read.
41 }
42 DCHECK(suffix_length_ >= count);
43 // Read is satisfied by the suffix.
44 std::copy(suffix_, suffix_ + count, out);
45 suffix_ += count;
46 suffix_length_ -= count;
47 return true;
48 }
49
ReadN(size_t count,SpdyPinnableBufferPiece * out)50 bool SpdyPrefixedBufferReader::ReadN(size_t count,
51 SpdyPinnableBufferPiece* out) {
52 if (Available() < count)
53 return false;
54
55 out->storage_.reset();
56 out->length_ = count;
57
58 if (prefix_length_ >= count) {
59 // Read is fully satisfied by the prefix.
60 out->buffer_ = prefix_;
61 prefix_ += count;
62 prefix_length_ -= count;
63 return true;
64 } else if (prefix_length_ != 0) {
65 // Read is only partially satisfied by the prefix. We need to allocate
66 // contiguous storage as the read spans the prefix & suffix.
67 out->storage_.reset(new char[count]);
68 out->buffer_ = out->storage_.get();
69 ReadN(count, out->storage_.get());
70 return true;
71 } else {
72 DCHECK(suffix_length_ >= count);
73 // Read is fully satisfied by the suffix.
74 out->buffer_ = suffix_;
75 suffix_ += count;
76 suffix_length_ -= count;
77 return true;
78 }
79 }
80
81 } // namespace net
82