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 5 #include "content/browser/speech/chunked_byte_buffer.h" 6 7 #include <algorithm> 8 9 #include "base/basictypes.h" 10 #include "base/lazy_instance.h" 11 #include "base/logging.h" 12 13 namespace { 14 15 static const size_t kHeaderLength = sizeof(uint32); 16 17 COMPILE_ASSERT(sizeof(size_t) >= kHeaderLength, 18 ChunkedByteBufferNotSupportedOnThisArchitecture); 19 20 uint32 ReadBigEndian32(const uint8* buffer) { 21 return (static_cast<uint32>(buffer[3])) | 22 (static_cast<uint32>(buffer[2]) << 8) | 23 (static_cast<uint32>(buffer[1]) << 16) | 24 (static_cast<uint32>(buffer[0]) << 24); 25 } 26 27 } // namespace 28 29 namespace content { 30 31 ChunkedByteBuffer::ChunkedByteBuffer() 32 : partial_chunk_(new Chunk()), 33 total_bytes_stored_(0) { 34 } 35 36 ChunkedByteBuffer::~ChunkedByteBuffer() { 37 Clear(); 38 } 39 40 void ChunkedByteBuffer::Append(const uint8* start, size_t length) { 41 size_t remaining_bytes = length; 42 const uint8* next_data = start; 43 44 while (remaining_bytes > 0) { 45 DCHECK(partial_chunk_ != NULL); 46 size_t insert_length = 0; 47 bool header_completed = false; 48 bool content_completed = false; 49 std::vector<uint8>* insert_target; 50 51 if (partial_chunk_->header.size() < kHeaderLength) { 52 const size_t bytes_to_complete_header = 53 kHeaderLength - partial_chunk_->header.size(); 54 insert_length = std::min(bytes_to_complete_header, remaining_bytes); 55 insert_target = &partial_chunk_->header; 56 header_completed = (remaining_bytes >= bytes_to_complete_header); 57 } else { 58 DCHECK_LT(partial_chunk_->content->size(), 59 partial_chunk_->ExpectedContentLength()); 60 const size_t bytes_to_complete_chunk = 61 partial_chunk_->ExpectedContentLength() - 62 partial_chunk_->content->size(); 63 insert_length = std::min(bytes_to_complete_chunk, remaining_bytes); 64 insert_target = partial_chunk_->content.get(); 65 content_completed = (remaining_bytes >= bytes_to_complete_chunk); 66 } 67 68 DCHECK_GT(insert_length, 0U); 69 DCHECK_LE(insert_length, remaining_bytes); 70 DCHECK_LE(next_data + insert_length, start + length); 71 insert_target->insert(insert_target->end(), 72 next_data, 73 next_data + insert_length); 74 next_data += insert_length; 75 remaining_bytes -= insert_length; 76 77 if (header_completed) { 78 DCHECK_EQ(partial_chunk_->header.size(), kHeaderLength); 79 if (partial_chunk_->ExpectedContentLength() == 0) { 80 // Handle zero-byte chunks. 81 chunks_.push_back(partial_chunk_.release()); 82 partial_chunk_.reset(new Chunk()); 83 } else { 84 partial_chunk_->content->reserve( 85 partial_chunk_->ExpectedContentLength()); 86 } 87 } else if (content_completed) { 88 DCHECK_EQ(partial_chunk_->content->size(), 89 partial_chunk_->ExpectedContentLength()); 90 chunks_.push_back(partial_chunk_.release()); 91 partial_chunk_.reset(new Chunk()); 92 } 93 } 94 DCHECK_EQ(next_data, start + length); 95 total_bytes_stored_ += length; 96 } 97 98 void ChunkedByteBuffer::Append(const std::string& string) { 99 Append(reinterpret_cast<const uint8*>(string.data()), string.size()); 100 } 101 102 bool ChunkedByteBuffer::HasChunks() const { 103 return !chunks_.empty(); 104 } 105 106 scoped_ptr< std::vector<uint8> > ChunkedByteBuffer::PopChunk() { 107 if (chunks_.empty()) 108 return scoped_ptr< std::vector<uint8> >(); 109 scoped_ptr<Chunk> chunk(*chunks_.begin()); 110 chunks_.weak_erase(chunks_.begin()); 111 DCHECK_EQ(chunk->header.size(), kHeaderLength); 112 DCHECK_EQ(chunk->content->size(), chunk->ExpectedContentLength()); 113 total_bytes_stored_ -= chunk->content->size(); 114 total_bytes_stored_ -= kHeaderLength; 115 return chunk->content.Pass(); 116 } 117 118 void ChunkedByteBuffer::Clear() { 119 chunks_.clear(); 120 partial_chunk_.reset(new Chunk()); 121 total_bytes_stored_ = 0; 122 } 123 124 ChunkedByteBuffer::Chunk::Chunk() 125 : content(new std::vector<uint8>()) { 126 } 127 128 ChunkedByteBuffer::Chunk::~Chunk() { 129 } 130 131 size_t ChunkedByteBuffer::Chunk::ExpectedContentLength() const { 132 DCHECK_EQ(header.size(), kHeaderLength); 133 return static_cast<size_t>(ReadBigEndian32(&header[0])); 134 } 135 136 } // namespace content 137