serialization.h

Go to the documentation of this file.

// -*- mode: c++; tab-width: 4; indent-tabs-mode: t; eval: (progn (c-set-style "stroustrup") (c-set-offset 'innamespace 0)); -*-
// vi:set ts=4 sts=4 sw=4 noet :
// Copyright 2010, The TPIE development team
// 
// This file is part of TPIE.
// 
// TPIE is free software: you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License as published by the
// Free Software Foundation, either version 3 of the License, or (at your
// option) any later version.
// 
// TPIE is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
// License for more details.
// 
// You should have received a copy of the GNU Lesser General Public License
// along with TPIE.  If not, see <http://www.gnu.org/licenses/>
#ifndef __TPIE_SERIALIZATION_H__
#define __TPIE_SERIALIZATION_H__


#include <tpie/config.h>
#include <tpie/portability.h>
#include <tpie/hash_map.h>
#include <vector>
#include <utility>
#include <typeinfo>

#include <type_traits>
#include <cstdint>
#include <istream>
#include <ostream>
#include <cstring>

namespace tpie {


struct serialization_error: public std::runtime_error {
    explicit serialization_error(const std::string & what): std::runtime_error(what) {}
};



class serializer {
public:
    serializer(std::ostream & out, bool typesafe=false): m_out(out), m_typesafe(false) {
        *this << "TPIE Serialization" //File header
              << (uint16_t)1   //File version
              << typesafe;            //Do we serialize typeids before each actual item?
        m_typesafe = typesafe;
    }

    template <typename T>
    inline serializer & write(const T * data, size_t l) {
        *this << (uint16_t)l;
        for (size_t i=0; i < l; ++i)
            *this << data[i];
        return *this;
    }
    template <typename T>
    inline typename std::enable_if<std::is_fundamental<T>::value || std::is_enum<T>::value,
                                     serializer &>::type operator << (const T & x) {
        write_type<T>();
        m_out.write(reinterpret_cast<const char*>(&x), sizeof(T));
        return * this;
    }

    template <typename T1, typename T2>
    inline serializer & operator <<(const std::pair<T1, T2> & p) {
        write_type<std::pair<T1,T2> >();
        return *this << p.first << p.second;
    }

    template <typename T>
    inline serializer & operator <<(const std::vector<T> & v) {
        write_type<std::vector<T> >();
        *this << (uint16_t)v.size();
        for (size_t i=0; i < v.size(); ++i)
            *this << v[i];
        return *this;
    }

    inline serializer & operator <<(const char * data) {write_type<std::string>(); return write(data, strlen(data));}
    inline serializer & operator <<(const std::string & s) {write_type<std::string>(); return write(s.c_str(), s.size());}
private:
    template <typename T>
    void write_type() {
        if (m_typesafe) {
            hash<const char *> h;
            m_out << (uint8_t)(h(typeid(T).name()) % 256);
        }
    }
        
    std::ostream & m_out;
    bool m_typesafe;
};

class unserializer {
public:
    unserializer(std::istream & in): m_in(in), m_typesafe(false) {
        //Validate header;
        *this << "TPIE Serialization" 
              << (uint16_t)1;
        bool typesafe;
        *this >> typesafe;
        m_typesafe=typesafe;
    }

    template <typename T>
    inline unserializer & operator <<(const T & x) {
        T y;
        *this >> y;
        if (y != x) throw serialization_error("Verification failed");
        return *this;
    }

    inline unserializer & operator <<(const char * x) {
        std::string y;
        *this >> y;
        if (y != x) throw serialization_error("Verification failed");
        return *this;
    }

    template <typename T>
    inline unserializer & read(T * array, size_t & size) {
        uint16_t x;
        *this >> x;
        if (x > size) throw serialization_error("array too short");
        size=x;
        for (size_t i=0; i < size; ++i)
            *this >> array[i];
        return *this;
    }

    template <typename T>
    inline typename std::enable_if<std::is_fundamental<T>::value || std::is_enum<T>::value, unserializer &>::type operator >> (T & x) {
        check_type<T>();
        char * y = reinterpret_cast<char*>(&x);
        m_in.read(y, sizeof(T));
        if (m_in.eof() || m_in.fail()) throw serialization_error("Unexpected end-of-file");
        return *this;
    }

    template <typename T1, typename T2>
    inline unserializer & operator >>(std::pair<T1, T2> & p) {
        check_type<std::pair<T1, T2> >();
        return *this >> p.first >> p.second;
    }

    template <typename T>
    inline unserializer & operator >> (std::vector<T> & v) {
        check_type<std::vector<T> >();
        uint16_t size;
        *this >> size;
        v.clear();
        for (size_t i=0; i < size; ++i) {
            v.push_back(T());
            *this >> v.back();
        }
        return *this;
    }

    inline unserializer & operator >>(std::string & s) {
        check_type<std::string>();
        s.clear();
        uint16_t size;
        *this >> size;
        for (size_t i=0; i < size; ++i) {
            char x;
            *this >> x;
            s.push_back(x);
        }
        return *this;
    }

private:
    template <typename T>
    void check_type() {
        if (!m_typesafe) return;
        hash<const char *> h;
        uint8_t hash = h(typeid(T).name()) % 256;
        uint8_t s_hash;
        m_in >> s_hash;
        if (s_hash == hash) return;
        std::stringstream ss;
        ss << "Serialization type error, input type did not match expected type: " << typeid(T).name();
        throw serialization_error(ss.str());
    }

    std::istream & m_in;
    bool m_typesafe;
};

} //namespace tpie
#endif /*__TPIE_SERIALIZATION_H__*/