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// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "media/base/byte_queue.h"
#include "base/logging.h"
namespace media {
// Default starting size for the queue.
enum { kDefaultQueueSize = 1024 };
ByteQueue::ByteQueue()
: buffer_(new uint8_t[kDefaultQueueSize]),
size_(kDefaultQueueSize),
offset_(0),
used_(0) {}
ByteQueue::~ByteQueue() {}
void ByteQueue::Reset() {
offset_ = 0;
used_ = 0;
}
void ByteQueue::Push(const uint8_t* data, int size) {
DCHECK(data);
DCHECK_GT(size, 0);
size_t size_needed = used_ + size;
// Check to see if we need a bigger buffer.
if (size_needed > size_) {
size_t new_size = 2 * size_;
while (size_needed > new_size && new_size > size_)
new_size *= 2;
// Sanity check to make sure we didn't overflow.
CHECK_GT(new_size, size_);
scoped_ptr<uint8_t[]> new_buffer(new uint8_t[new_size]);
// Copy the data from the old buffer to the start of the new one.
if (used_ > 0)
memcpy(new_buffer.get(), front(), used_);
buffer_.reset(new_buffer.release());
size_ = new_size;
offset_ = 0;
} else if ((offset_ + used_ + size) > size_) {
// The buffer is big enough, but we need to move the data in the queue.
memmove(buffer_.get(), front(), used_);
offset_ = 0;
}
memcpy(front() + used_, data, size);
used_ += size;
}
void ByteQueue::Peek(const uint8_t** data, int* size) const {
DCHECK(data);
DCHECK(size);
*data = front();
*size = used_;
}
void ByteQueue::Pop(int count) {
DCHECK_LE(count, used_);
offset_ += count;
used_ -= count;
// Move the offset back to 0 if we have reached the end of the buffer.
if (offset_ == size_) {
DCHECK_EQ(used_, 0);
offset_ = 0;
}
}
uint8_t* ByteQueue::front() const {
return buffer_.get() + offset_;
}
} // namespace media
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