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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/speech/chunked_byte_buffer.h"
#include <algorithm>
#include <memory>
#include <utility>
#include "base/big_endian.h"
#include "base/check_op.h"
#include "base/lazy_instance.h"
namespace {
static const size_t kHeaderLength = sizeof(uint32_t);
static_assert(sizeof(size_t) >= kHeaderLength,
"chunked byte buffer not supported on this architecture");
} // namespace
namespace speech {
ChunkedByteBuffer::ChunkedByteBuffer()
: partial_chunk_(new Chunk()), total_bytes_stored_(0) {}
ChunkedByteBuffer::~ChunkedByteBuffer() {
Clear();
}
void ChunkedByteBuffer::Append(const uint8_t* start, size_t length) {
size_t remaining_bytes = length;
const uint8_t* next_data = start;
while (remaining_bytes > 0) {
DCHECK(partial_chunk_ != nullptr);
size_t insert_length = 0;
bool header_completed = false;
bool content_completed = false;
std::vector<uint8_t>* insert_target;
if (partial_chunk_->header.size() < kHeaderLength) {
const size_t bytes_to_complete_header =
kHeaderLength - partial_chunk_->header.size();
insert_length = std::min(bytes_to_complete_header, remaining_bytes);
insert_target = &partial_chunk_->header;
header_completed = (remaining_bytes >= bytes_to_complete_header);
} else {
DCHECK_LT(partial_chunk_->content->size(),
partial_chunk_->ExpectedContentLength());
const size_t bytes_to_complete_chunk =
partial_chunk_->ExpectedContentLength() -
partial_chunk_->content->size();
insert_length = std::min(bytes_to_complete_chunk, remaining_bytes);
insert_target = partial_chunk_->content.get();
content_completed = (remaining_bytes >= bytes_to_complete_chunk);
}
DCHECK_GT(insert_length, 0U);
DCHECK_LE(insert_length, remaining_bytes);
DCHECK_LE(next_data + insert_length, start + length);
insert_target->insert(insert_target->end(), next_data,
next_data + insert_length);
next_data += insert_length;
remaining_bytes -= insert_length;
if (header_completed) {
DCHECK_EQ(partial_chunk_->header.size(), kHeaderLength);
if (partial_chunk_->ExpectedContentLength() == 0) {
// Handle zero-byte chunks.
chunks_.push_back(std::move(partial_chunk_));
partial_chunk_ = std::make_unique<Chunk>();
} else {
partial_chunk_->content->reserve(
partial_chunk_->ExpectedContentLength());
}
} else if (content_completed) {
DCHECK_EQ(partial_chunk_->content->size(),
partial_chunk_->ExpectedContentLength());
chunks_.push_back(std::move(partial_chunk_));
partial_chunk_ = std::make_unique<Chunk>();
}
}
DCHECK_EQ(next_data, start + length);
total_bytes_stored_ += length;
}
void ChunkedByteBuffer::Append(base::StringPiece string) {
Append(reinterpret_cast<const uint8_t*>(string.data()), string.size());
}
bool ChunkedByteBuffer::HasChunks() const {
return !chunks_.empty();
}
std::unique_ptr<std::vector<uint8_t>> ChunkedByteBuffer::PopChunk() {
if (chunks_.empty())
return nullptr;
std::unique_ptr<Chunk> chunk = std::move(*chunks_.begin());
chunks_.erase(chunks_.begin());
DCHECK_EQ(chunk->header.size(), kHeaderLength);
DCHECK_EQ(chunk->content->size(), chunk->ExpectedContentLength());
total_bytes_stored_ -= chunk->content->size();
total_bytes_stored_ -= kHeaderLength;
return std::move(chunk->content);
}
void ChunkedByteBuffer::Clear() {
chunks_.clear();
partial_chunk_ = std::make_unique<Chunk>();
total_bytes_stored_ = 0;
}
ChunkedByteBuffer::Chunk::Chunk() : content(new std::vector<uint8_t>()) {}
ChunkedByteBuffer::Chunk::~Chunk() {}
size_t ChunkedByteBuffer::Chunk::ExpectedContentLength() const {
DCHECK_EQ(header.size(), kHeaderLength);
uint32_t content_length = 0;
base::ReadBigEndian(&header[0], &content_length);
return static_cast<size_t>(content_length);
}
} // namespace speech
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