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#pragma once
#include "endianness.hpp"
#include "reader.hpp"
#include "write_to_sink.hpp"
#include "../base/assert.hpp"
#include "../base/base.hpp"
#include "../std/string.hpp"
#include "../std/utility.hpp"
#include "../std/vector.hpp"
#include "../std/scoped_ptr.hpp"
template <typename ItT, typename TDstStream>
void WriteVarSerialVector(ItT begin, ItT end, TDstStream & dst)
{
vector<uint32_t> offsets;
uint32_t offset = 0;
for (ItT it = begin; it != end; ++it)
{
offset += it->size() * sizeof((*it)[0]);
offsets.push_back(offset);
}
WriteToSink(dst, static_cast<uint32_t>(end - begin));
for (size_t i = 0; i < offsets.size(); ++i)
WriteToSink(dst, offsets[i]);
for (ItT it = begin; it != end; ++it)
{
typename ItT::value_type const & v = *it;
if (!v.empty())
dst.Write(&v[0], v.size() * sizeof(v[0]));
}
}
template <class WriterT> class VarSerialVectorWriter
{
public:
// Actually, it is possible to refactor to accept maxPossibleSize (i.e. capacity) instead of size.
VarSerialVectorWriter(WriterT & writer, uint32_t size)
: m_Writer(writer), m_Size(size), m_RecordNumber(0)
{
WriteToSink(m_Writer, size);
m_SizesOffset = m_Writer.Pos();
m_Writer.Seek(m_SizesOffset + size * 4);
}
~VarSerialVectorWriter()
{
CHECK_EQUAL(m_RecordNumber, m_Size, ());
}
void FinishRecord()
{
CHECK_LESS(m_RecordNumber, m_Size, ());
uint64_t const pos = m_Writer.Pos();
uint64_t recordSize64 = pos - m_SizesOffset - m_Size * 4;
uint32_t recordSize = static_cast<uint32_t>(recordSize64);
CHECK_EQUAL(recordSize, recordSize64, ());
m_Writer.Seek(m_SizesOffset + m_RecordNumber * 4);
WriteToSink(m_Writer, recordSize);
m_Writer.Seek(pos);
++m_RecordNumber;
}
private:
WriterT & m_Writer;
uint64_t m_SizesOffset;
uint32_t m_Size;
uint32_t m_RecordNumber;
};
template <class ReaderT>
class VarSerialVectorReader
{
public:
template <typename SourceT>
explicit VarSerialVectorReader(SourceT & source) :
/// Reading this code can blow your mind :)
/// Initialization (and declaration below) order of m_offsetsReader and m_dataReader matters!!!
/// @see ReaderSource::SubReader - it's not constant.
/// @todo Do this stuff in a better way.
m_size(ReadPrimitiveFromSource<uint32_t>(source)),
m_offsetsReader(source.SubReader(m_size * sizeof(uint32_t))),
m_dataReader(source.SubReader())
{
}
string Read(uint64_t i) const
{
size_t begin =
i == 0 ? 0 : ReadPrimitiveFromPos<uint32_t>(m_offsetsReader, (i - 1) * sizeof(uint32_t));
size_t end = ReadPrimitiveFromPos<uint32_t>(m_offsetsReader, i * sizeof(uint32_t));
string result;
result.resize(end - begin);
ReadFromPos(m_dataReader, begin, (void *)result.data(), end - begin);
return result;
}
ReaderT SubReader(uint64_t i) const
{
size_t begin =
i == 0 ? 0 : ReadPrimitiveFromPos<uint32_t>(m_offsetsReader, (i - 1) * sizeof(uint32_t));
size_t end = ReadPrimitiveFromPos<uint32_t>(m_offsetsReader, i * sizeof(uint32_t));
return m_dataReader.SubReader(begin, end - begin);
}
uint64_t Size() const
{
return m_size;
}
private:
/// @note Do NOT change declaration order.
uint64_t m_size;
ReaderT m_offsetsReader;
ReaderT m_dataReader;
};
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