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/*
* Copyright (C) 2012 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.
*/
#pragma once
#include <wtf/Deque.h>
#include <wtf/text/ParsingUtilities.h>
namespace WTF {
template <typename T, size_t BlockSize>
class StreamBuffer {
WTF_MAKE_FAST_ALLOCATED;
private:
typedef Vector<T> Block;
public:
StreamBuffer()
: m_size(0)
, m_readOffset(0)
{
}
~StreamBuffer()
{
}
bool isEmpty() const { return !size(); }
void append(std::span<const T> data)
{
if (!data.size())
return;
m_size += data.size();
while (data.size()) {
if (!m_buffer.size() || m_buffer.last()->size() == BlockSize)
m_buffer.append(makeUnique<Block>());
size_t appendSize = std::min(BlockSize - m_buffer.last()->size(), data.size());
m_buffer.last()->append(consumeSpan(data, appendSize));
}
}
void append(const T* data, size_t size) { append(std::span { data, size }); }
// This function consume data in the fist block.
// Specified size must be less than over equal to firstBlockSize().
void consume(size_t size)
{
ASSERT(m_size >= size);
if (!m_size)
return;
ASSERT(m_buffer.size() > 0);
ASSERT(m_readOffset + size <= m_buffer.first()->size());
m_readOffset += size;
m_size -= size;
if (m_readOffset >= m_buffer.first()->size()) {
m_readOffset = 0;
m_buffer.removeFirst();
}
}
size_t size() const { return m_size; }
const T* firstBlockData() const
{
if (!m_size)
return 0;
ASSERT(m_buffer.size() > 0);
return &m_buffer.first()->data()[m_readOffset];
}
size_t firstBlockSize() const
{
if (!m_size)
return 0;
ASSERT(m_buffer.size() > 0);
return m_buffer.first()->size() - m_readOffset;
}
std::span<const T> firstBlockSpan() const { return std::span { firstBlockData(), firstBlockSize() }; }
private:
size_t m_size;
size_t m_readOffset;
Deque<std::unique_ptr<Block>> m_buffer;
};
} // namespace WTF
using WTF::StreamBuffer;
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