Serialize.h

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#ifndef _SERIALIZE_H_
#define _SERIALIZE_H_
#include <iostream>
#include <sstream>
#include <vector>
#include <set>
#include <map>
#include <tuple>
 
// our "interface" for encoding
// template<class T>
// void encode(std::streambuf& os, T t);
 
// our "interface" for decoding
// template<class T>
// void decode(std::streambuf& os, T& t);
 
// helpers to encode pointers to arrays of data
// also works for single elements
template<class T>
void encode(std::streambuf& os, T* t, size_t size = 1) {
  os.sputn((char*)t, sizeof(T)*size);
}
 
template<class T>
void decode(std::streambuf& os, T* t, size_t size = 1) {
  os.sgetn((char*)t, sizeof(T)*size);
}
 
// This is a macro to allow easy construction of encode and decode for
// trivial to serialize types.
// Trivially serializable types are any type that can be copied by
// copying its memory.
// As a rule of thumb, anything with a pointer is not trivially serializable
#define TRIVIALLY_SERIALIZABLE(T)               \
  void encode(std::streambuf& os, const T& t) { \
    encode(os, &t);                             \
  }                                             \
  void decode(std::streambuf& os, T& t) {       \
    decode(os, &t);                             \
  }
 
// integral types serialization methods
TRIVIALLY_SERIALIZABLE(char);
TRIVIALLY_SERIALIZABLE(unsigned char);
TRIVIALLY_SERIALIZABLE(short int);
TRIVIALLY_SERIALIZABLE(unsigned short int);
TRIVIALLY_SERIALIZABLE(int);
TRIVIALLY_SERIALIZABLE(unsigned int);
TRIVIALLY_SERIALIZABLE(long int);
TRIVIALLY_SERIALIZABLE(unsigned long int);
TRIVIALLY_SERIALIZABLE(long long int);
TRIVIALLY_SERIALIZABLE(unsigned long long int);
 
 
// STL container serializers
// Some of these functions have template specializations to increase performance when
// the entire structure exists as a contiguous piece of memory
// we need some prototypes TODO: clean up order of functions
template<class T>
void decode(std::streambuf& os, std::set<T>& v);
 
// std::pair
// we pray that std::pair is contiguous memory
// TODO: is it?
template<class T, class S>
inline
typename std::enable_if<std::is_pod<T>::value && std::is_pod<S>::value, void>::type
encode(std::streambuf& os, const std::pair<T, S>& p) {
  encode(os, &p);
}
 
// specialization for non-contiguous mem
template<class T, class S>
inline
typename std::enable_if<!(std::is_pod<T>::value && std::is_pod<S>::value), void>::type
encode(std::streambuf& os, const std::pair<T, S>& p) {
  encode(os, p.first);
  encode(os, p.second);
}
 
template<class T, class S>
inline
typename std::enable_if<std::is_pod<T>::value && std::is_pod<S>::value, void>::type
decode(std::streambuf& os, std::pair<T, S>& p) {
  decode(os, &p);
}
 
template<class T, class S>
inline
typename std::enable_if<!(std::is_pod<T>::value && std::is_pod<S>::value), void>::type
decode(std::streambuf& os, std::pair<T, S>& p) {
  decode(os, p.first);
  decode(os, p.second);
}
 
// helper to encode a size plus an interator
template<class Iter>
inline
void encode_iter(std::streambuf& os, size_t size, Iter begin, Iter end);
 
// std::vector
 
// specialized for contiguous memory
template<class T>
inline
typename std::enable_if<std::is_pod<T>::value, void>::type
encode(std::streambuf& os, const std::vector<T>& v) {
  encode(os, v.size());
  encode(os, v.data(), v.size());
}
 
template<class T>
inline
typename std::enable_if<!std::is_pod<T>::value, void>::type
encode(std::streambuf& os, const std::vector<T>& v) {
  encode_iter(os, v.size(), v.begin(), v.end());
}
 
template<class T>
inline
typename std::enable_if<std::is_pod<T>::value, void>::type
decode(std::streambuf& os, std::vector<T>& v) {
  // read size of the vector
  size_t size;
  decode(os, size);
  v.resize(size); // we know the size, so we reserve space
  decode(os, v.data(), size);
}
 
template<class T>
inline
typename std::enable_if<!std::is_pod<T>::value, void>::type
decode(std::streambuf& os, std::vector<T>& v) {
  v.clear();
  size_t size;
  decode(os, size);
  v.reserve(size);
  for(size_t i = 0; i < size; i++) {
    typename std::remove_reference<decltype(v)>::type::value_type t;
    decode(os, t);
    v.emplace_back(std::move(t));
  }
}
 
// std::set
template<class T>
inline
void encode(std::streambuf& os, const std::set<T>& v) {
  encode_iter(os, v.size(), v.begin(), v.end());
}
 
template<class T>
inline
void decode_thing(std::streambuf& os, T& v) {
  v.clear();
  size_t size;
  decode(os, size);
  auto hint = v.end();
  for(size_t i = 0; i < size; i++) {
    typename std::remove_reference<decltype(v)>::type::value_type t;
    decode(os, t);
    hint = v.emplace_hint(hint, std::move(t));
  }
}
 
template<class T>
inline
void decode(std::streambuf& os, std::set<T>& v) {
  decode_thing(os, v);
}
 
// std::map
template<class T, class S>
inline
void encode(std::streambuf& os, const std::map<T, S>& v) {
  encode_iter(os, v.size(), v.begin(), v.end());
}
 
template<class T, class S>
inline
void decode(std::streambuf& os, std::map<T, S>& v) {
  decode_thing(os, v);
}
 
// std::multimap
template<class T, class S>
inline
void encode(std::streambuf& os, const std::multimap<T, S>& v) {
  encode_iter(os, v.size(), v.begin(), v.end());
}
 
template<class T, class S>
inline
void decode(std::streambuf& os, std::multimap<T, S>& v) {
  decode_thing(os, v);
}
 
template<class Iter>
inline
void encode_iter(std::streambuf& os, size_t size, Iter begin, Iter end) {
  encode(os, size);
  for (; begin != end; ++begin) {
    encode(os, *begin);
  }
}
 
#endif