old-nall/serializer.hpp
2016-07-09 09:51:02 +02:00

146 lines
4.2 KiB
C++

#pragma once
//serializer: a class designed to save and restore the state of classes.
//
//benefits:
//- data() will be portable in size (it is not necessary to specify type sizes.)
//- data() will be portable in endianness (always stored internally as little-endian.)
//- one serialize function can both save and restore class states.
//
//caveats:
//- only plain-old-data can be stored. complex classes must provide serialize(serializer&);
//- floating-point usage is not portable across different implementations
#include <nall/stdint.hpp>
#include <nall/traits.hpp>
#include <nall/utility.hpp>
namespace nall {
struct serializer;
template<typename T>
struct has_serialize {
template<typename C> static auto test(decltype(std::declval<C>().serialize(std::declval<serializer&>()))*) -> char;
template<typename C> static auto test(...) -> long;
static const bool value = sizeof(test<T>(0)) == sizeof(char);
};
struct serializer {
enum Mode : uint { Load, Save, Size };
auto mode() const -> Mode {
return _mode;
}
auto data() const -> const uint8_t* {
return _data;
}
auto size() const -> uint {
return _size;
}
auto capacity() const -> uint {
return _capacity;
}
template<typename T> auto floatingpoint(T& value) -> serializer& {
enum { size = sizeof(T) };
//this is rather dangerous, and not cross-platform safe;
//but there is no standardized way to export FP-values
auto p = (uint8_t*)&value;
if(_mode == Save) {
for(uint n = 0; n < size; n++) _data[_size++] = p[n];
} else if(_mode == Load) {
for(uint n = 0; n < size; n++) p[n] = _data[_size++];
} else {
_size += size;
}
return *this;
}
template<typename T> auto integer(T& value) -> serializer& {
enum { size = std::is_same<bool, T>::value ? 1 : sizeof(T) };
if(_mode == Save) {
for(uint n = 0; n < size; n++) _data[_size++] = (uintmax_t)value >> (n << 3);
} else if(_mode == Load) {
value = 0;
for(uint n = 0; n < size; n++) value |= (uintmax_t)_data[_size++] << (n << 3);
} else if(_mode == Size) {
_size += size;
}
return *this;
}
template<typename T, int N> auto array(T (&array)[N]) -> serializer& {
for(uint n = 0; n < N; n++) operator()(array[n]);
return *this;
}
template<typename T> auto array(T array, uint size) -> serializer& {
for(uint n = 0; n < size; n++) operator()(array[n]);
return *this;
}
template<typename T> auto operator()(T& value, typename std::enable_if<has_serialize<T>::value>::type* = 0) -> serializer& { value.serialize(*this); return *this; }
template<typename T> auto operator()(T& value, typename std::enable_if<std::is_integral<T>::value>::type* = 0) -> serializer& { return integer(value); }
template<typename T> auto operator()(T& value, typename std::enable_if<std::is_floating_point<T>::value>::type* = 0) -> serializer& { return floatingpoint(value); }
template<typename T> auto operator()(T& value, typename std::enable_if<std::is_array<T>::value>::type* = 0) -> serializer& { return array(value); }
template<typename T> auto operator()(T& value, uint size, typename std::enable_if<std::is_pointer<T>::value>::type* = 0) -> serializer& { return array(value, size); }
auto operator=(const serializer& s) -> serializer& {
if(_data) delete[] _data;
_mode = s._mode;
_data = new uint8_t[s._capacity];
_size = s._size;
_capacity = s._capacity;
memcpy(_data, s._data, s._capacity);
return *this;
}
auto operator=(serializer&& s) -> serializer& {
if(_data) delete[] _data;
_mode = s._mode;
_data = s._data;
_size = s._size;
_capacity = s._capacity;
s._data = nullptr;
return *this;
}
serializer() = default;
serializer(const serializer& s) { operator=(s); }
serializer(serializer&& s) { operator=(move(s)); }
serializer(uint capacity) {
_mode = Save;
_data = new uint8_t[capacity]();
_size = 0;
_capacity = capacity;
}
serializer(const uint8_t* data, uint capacity) {
_mode = Load;
_data = new uint8_t[capacity];
_size = 0;
_capacity = capacity;
memcpy(_data, data, capacity);
}
~serializer() {
if(_data) delete[] _data;
}
private:
Mode _mode = Size;
uint8_t* _data = nullptr;
uint _size = 0;
uint _capacity = 0;
};
};