blob: c5ecec9ee6e15768aa8b09d8a62c59be38f98049 [file] [log] [blame]
/*
* Copyright (C) 2010-2021 Apple 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:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS 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 APPLE INC. OR ITS 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 "config.h"
#include <wtf/persistence/PersistentDecoder.h>
#include <wtf/persistence/PersistentEncoder.h>
namespace WTF {
namespace Persistence {
Decoder::Decoder(Span<const uint8_t> span)
: m_buffer(span)
, m_bufferPosition(span.begin())
{
}
Decoder::~Decoder()
{
}
bool Decoder::bufferIsLargeEnoughToContain(size_t size) const
{
return size <= static_cast<size_t>(m_buffer.end() - m_bufferPosition);
}
const uint8_t* Decoder::bufferPointerForDirectRead(size_t size)
{
if (!bufferIsLargeEnoughToContain(size))
return nullptr;
auto data = m_bufferPosition;
m_bufferPosition += size;
Encoder::updateChecksumForData(m_sha1, { data, size });
return data;
}
bool Decoder::decodeFixedLengthData(Span<uint8_t> span)
{
auto buffer = bufferPointerForDirectRead(span.size());
if (!buffer)
return false;
memcpy(span.data(), buffer, span.size());
return true;
}
bool Decoder::rewind(size_t size)
{
if (size <= static_cast<size_t>(m_bufferPosition - m_buffer.begin())) {
m_bufferPosition -= size;
return true;
}
return false;
}
template<typename T>
Decoder& Decoder::decodeNumber(std::optional<T>& optional)
{
if (!bufferIsLargeEnoughToContain(sizeof(T)))
return *this;
T value;
memcpy(&value, m_bufferPosition, sizeof(T));
m_bufferPosition += sizeof(T);
Encoder::updateChecksumForNumber(m_sha1, value);
optional = value;
return *this;
}
Decoder& Decoder::operator>>(std::optional<bool>& result)
{
return decodeNumber(result);
}
Decoder& Decoder::operator>>(std::optional<uint8_t>& result)
{
return decodeNumber(result);
}
Decoder& Decoder::operator>>(std::optional<uint16_t>& result)
{
return decodeNumber(result);
}
Decoder& Decoder::operator>>(std::optional<int16_t>& result)
{
return decodeNumber(result);
}
Decoder& Decoder::operator>>(std::optional<uint32_t>& result)
{
return decodeNumber(result);
}
Decoder& Decoder::operator>>(std::optional<uint64_t>& result)
{
return decodeNumber(result);
}
Decoder& Decoder::operator>>(std::optional<int32_t>& result)
{
return decodeNumber(result);
}
Decoder& Decoder::operator>>(std::optional<int64_t>& result)
{
return decodeNumber(result);
}
Decoder& Decoder::operator>>(std::optional<float>& result)
{
return decodeNumber(result);
}
Decoder& Decoder::operator>>(std::optional<double>& result)
{
return decodeNumber(result);
}
bool Decoder::verifyChecksum()
{
SHA1::Digest computedHash;
m_sha1.computeHash(computedHash);
SHA1::Digest savedHash;
if (!decodeFixedLengthData({ savedHash.data(), sizeof(savedHash) }))
return false;
return computedHash == savedHash;
}
} // namespace Persistence
} // namespace WTF