endian: add convenience selectable convertor

This commit is contained in:
Danny Robson 2014-07-31 18:52:57 +10:00
parent 14fd62a64a
commit a3dcdeb7a3

View File

@ -20,8 +20,17 @@
#ifndef __UTIL_ENDIAN_HPP #ifndef __UTIL_ENDIAN_HPP
#define __UTIL_ENDIAN_HPP #define __UTIL_ENDIAN_HPP
#include <cstdint> #include "types/bits.hpp"
#include <cstdint>
#include <type_traits>
//-----------------------------------------------------------------------------
// Uses the TIFF header values. Just because. Don't rely on this.
enum class endian : uint16_t {
BIG = 0x4D4D,
LITTLE = 0x4949,
};
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
template <typename T> template <typename T>
@ -68,5 +77,31 @@ template <typename T> constexpr T btoh (T v) { return bswap (v); }
template <typename T> constexpr T ltoh (T v) { return v; } template <typename T> constexpr T ltoh (T v) { return v; }
#endif #endif
//-----------------------------------------------------------------------------
struct from_endian {
from_endian (endian _endian):
src (_endian)
{ ; }
template <typename T>
T operator() (const T v) const {
static_assert (std::is_integral<T>::value || std::is_enum<T>::value,
"endian conversion is only defined for integrals currently");
auto u = static_cast<
typename std::conditional<
std::is_signed<T>::value,
typename sized_type<T>::sint,
typename sized_type<T>::uint
>::type
> (v);
return static_cast<T> (
(src == endian::LITTLE) ? ltoh (u) : btoh (u)
);
}
endian src;
};
#endif #endif