serializer.hpp

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// Copyright (c) 2013-2018 Anton Kozhevnikov, Thomas Schulthess
// 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.
// 
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/** \file serializer.hpp
 *
 *  \brief Serializer for simple data structures.
 */
 
#ifndef __SERIALIZER_HPP__
#define __SERIALIZER_HPP__
 
#include <limits>
#include "core/mpi/communicator.hpp"
#include "SDDK/memory.hpp"
 
namespace sirius {
 
/// Serialize and deserialize objects.
class serializer
{
  private:
    /// Position in the stream. This is used during unpacking.
    size_t pos_{0};
    /// Data stream is represendted as a sequence of characters.
    std::vector<uint8_t> stream_;
  public:
 
    /// Copy n bytes into a serialization stream.
    void copyin(uint8_t const* ptr__, size_t nbytes__)
    {
        /* resize the array */
        stream_.resize(stream_.size() + nbytes__);
        /* copy from pointer */
        std::memcpy(&stream_[stream_.size() - nbytes__], ptr__, nbytes__);
    }
 
    /// Copy n bytes from the serialization stream.
    /** When data is copied out, the position inside a stream is shifted to n bytes forward. */
    void copyout(uint8_t* ptr__, size_t nbytes__)
    {
        std::memcpy(ptr__, &stream_[pos_], nbytes__);
        pos_ += nbytes__;
    }
 
    void send_recv(mpi::Communicator const& comm__, int source__, int dest__)
    {
        if (source__ == dest__) {
            return;
        }
 
        size_t sz;
 
        mpi::Request r1, r2;
 
        int tag = mpi::Communicator::get_tag(source__, dest__);
 
        if (comm__.rank() == source__) {
            sz = stream_.size();
            RTE_ASSERT(sz < static_cast<size_t>(std::numeric_limits<int>::max()));
            r1 = comm__.isend(&sz, 1, dest__, tag++);
            r2 = comm__.isend(&stream_[0], (int)sz, dest__, tag++);
        }
 
        if (comm__.rank() == dest__) {
            comm__.recv(&sz, 1, source__, tag++);
            stream_.resize(sz);
            comm__.recv(&stream_[0], (int)sz, source__, tag++);
        }
 
        if (comm__.rank() == source__) {
            r1.wait();
            r2.wait();
        }
    }
 
    std::vector<uint8_t> const& stream() const
    {
        return stream_;
    }
};
 
/// Serialize a single element.
template <typename T>
inline void serialize(serializer& s__, T var__)
{
    s__.copyin(reinterpret_cast<uint8_t const*>(&var__), sizeof(T));
}
 
/// Deserialize a single element.
template <typename T>
inline void deserialize(serializer& s__, T& var__)
{
    s__.copyout(reinterpret_cast<uint8_t*>(&var__), sizeof(T));
}
 
/// Serialize a vector.
template <typename T>
inline void serialize(serializer& s__, std::vector<T> const& vec__)
{
    serialize(s__, vec__.size());
    s__.copyin(reinterpret_cast<uint8_t const*>(&vec__[0]), sizeof(T) * vec__.size());
}
 
/// Deserialize a vector.
template <typename T>
inline void deserialize(serializer& s__, std::vector<T>& vec__)
{
    size_t sz;
    deserialize(s__, sz);
    vec__.resize(sz);
    s__.copyout(reinterpret_cast<uint8_t*>(&vec__[0]), sizeof(T) * vec__.size());
}
 
/// Serialize multidimentional array.
template <typename T, int N>
void serialize(serializer& s__, sddk::mdarray<T, N> const& array__)
{
    serialize(s__, array__.size());
    if (array__.size() == 0) {
        return;
    }
    for (int i = 0; i < N; i++) {
        serialize(s__, array__.dim(i).begin());
        serialize(s__, array__.dim(i).end());
    }
    s__.copyin(reinterpret_cast<uint8_t const*>(&array__[0]), sizeof(T) * array__.size());
}
 
/// Deserialize multidimentional array.
template <typename T, int N>
void deserialize(serializer& s__, sddk::mdarray<T, N>& array__)
{
    size_t sz;
    deserialize(s__, sz);
    if (sz == 0) {
        array__ = sddk::mdarray<T, N>();
        return;
    }
    std::array<sddk::mdarray_index_descriptor, N> dims;
    for (int i = 0; i < N; i++) {
        sddk::mdarray_index_descriptor::index_type begin, end;
        deserialize(s__, begin);
        deserialize(s__, end);
        dims[i] = sddk::mdarray_index_descriptor(begin, end);
    }
    array__ = sddk::mdarray<T, N>(dims);
    s__.copyout(reinterpret_cast<uint8_t*>(&array__[0]), sizeof(T) * array__.size());
}
 
/// Serialize block data descriptor.
inline void serialize(serializer& s__, mpi::block_data_descriptor const& dd__)
{
    serialize(s__, dd__.num_ranks);
    serialize(s__, dd__.counts);
    serialize(s__, dd__.offsets);
}
 
/// Deserialize block data descriptor.
inline void deserialize(serializer& s__, mpi::block_data_descriptor& dd__)
{
    deserialize(s__, dd__.num_ranks);
    deserialize(s__, dd__.counts);
    deserialize(s__, dd__.offsets);
}
 
}
 
#endif