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/*
* Copyright (C) 2013 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "third_party/blink/renderer/platform/wtf/typed_arrays/array_buffer_builder.h"
#include <limits>
#include "third_party/blink/renderer/platform/wtf/assertions.h"
namespace WTF {
static const int kDefaultBufferCapacity = 32768;
ArrayBufferBuilder::ArrayBufferBuilder()
: bytes_used_(0), variable_capacity_(true) {
buffer_ = ArrayBuffer::Create(kDefaultBufferCapacity, 1);
}
bool ArrayBufferBuilder::ExpandCapacity(unsigned size_to_increase) {
unsigned current_buffer_size = buffer_->ByteLength();
// If the size of the buffer exceeds max of unsigned, it can't be grown any
// more.
if (size_to_increase > std::numeric_limits<unsigned>::max() - bytes_used_)
return false;
unsigned new_buffer_size = bytes_used_ + size_to_increase;
// Grow exponentially if possible.
unsigned exponential_growth_new_buffer_size =
std::numeric_limits<unsigned>::max();
if (current_buffer_size <= std::numeric_limits<unsigned>::max() / 2)
exponential_growth_new_buffer_size = current_buffer_size * 2;
if (exponential_growth_new_buffer_size > new_buffer_size)
new_buffer_size = exponential_growth_new_buffer_size;
// Copy existing data in current buffer to new buffer.
scoped_refptr<ArrayBuffer> new_buffer =
ArrayBuffer::Create(new_buffer_size, 1);
if (!new_buffer)
return false;
memcpy(new_buffer->Data(), buffer_->Data(), bytes_used_);
buffer_ = new_buffer;
return true;
}
unsigned ArrayBufferBuilder::Append(const char* data, unsigned length) {
DCHECK_GT(length, 0u);
unsigned current_buffer_size = buffer_->ByteLength();
DCHECK_LE(bytes_used_, current_buffer_size);
unsigned remaining_buffer_space = current_buffer_size - bytes_used_;
unsigned bytes_to_save = length;
if (length > remaining_buffer_space) {
if (variable_capacity_) {
if (!ExpandCapacity(length))
return 0;
} else {
bytes_to_save = remaining_buffer_space;
}
}
memcpy(static_cast<char*>(buffer_->Data()) + bytes_used_, data,
bytes_to_save);
bytes_used_ += bytes_to_save;
return bytes_to_save;
}
scoped_refptr<ArrayBuffer> ArrayBufferBuilder::ToArrayBuffer() {
// Fully used. Return m_buffer as-is.
if (buffer_->ByteLength() == bytes_used_)
return buffer_;
return buffer_->Slice(0, bytes_used_);
}
String ArrayBufferBuilder::ToString() {
return String(static_cast<const char*>(buffer_->Data()), bytes_used_);
}
void ArrayBufferBuilder::ShrinkToFit() {
DCHECK_LE(bytes_used_, buffer_->ByteLength());
if (buffer_->ByteLength() > bytes_used_)
buffer_ = buffer_->Slice(0, bytes_used_);
}
} // namespace WTF
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