111 lines
3.8 KiB
C++
111 lines
3.8 KiB
C++
/*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*
|
|
* Copyright 2010-2014 Danny Robson <danny@nerdcruft.net>
|
|
*/
|
|
|
|
#ifndef __UTIL_ENDIAN_HPP
|
|
#define __UTIL_ENDIAN_HPP
|
|
|
|
#include "types/bits.hpp"
|
|
|
|
#include <cstdint>
|
|
#include <type_traits>
|
|
|
|
namespace util {
|
|
//-------------------------------------------------------------------------
|
|
// Uses the TIFF header values. Just because. Don't rely on this.
|
|
enum class endian : uint16_t {
|
|
BIG = 0x4D4D,
|
|
LITTLE = 0x4949,
|
|
};
|
|
|
|
//-------------------------------------------------------------------------
|
|
template <typename T>
|
|
constexpr T
|
|
bswap (T);
|
|
|
|
//template <> constexpr int8_t bswap ( int8_t v) { return v; }
|
|
//template <> constexpr int16_t bswap (int16_t v) { return __builtin_bswap16 (v); }
|
|
//template <> constexpr int32_t bswap (int32_t v) { return __builtin_bswap32 (v); }
|
|
//template <> constexpr int64_t bswap (int64_t v) { return __builtin_bswap64 (v); }
|
|
|
|
template <> constexpr uint8_t bswap ( uint8_t v) { return v; }
|
|
template <> constexpr uint16_t bswap (uint16_t v) { return __builtin_bswap16 (v); }
|
|
template <> constexpr uint32_t bswap (uint32_t v) { return __builtin_bswap32 (v); }
|
|
template <> constexpr uint64_t bswap (uint64_t v) { return __builtin_bswap64 (v); }
|
|
|
|
|
|
//-------------------------------------------------------------------------
|
|
template <typename T>
|
|
constexpr T
|
|
identity (T &&v) {
|
|
return v;
|
|
}
|
|
|
|
|
|
//-------------------------------------------------------------------------
|
|
#if defined(WORDS_BIGENDIAN)
|
|
template <typename T> constexpr T hton (T v) { return v; }
|
|
template <typename T> constexpr T ntoh (T v) { return v; }
|
|
|
|
template <typename T> constexpr T htob (T v) { return v; }
|
|
template <typename T> constexpr T htol (T v) { return bswap (v); }
|
|
|
|
template <typename T> constexpr T btoh (T v) { return v; }
|
|
template <typename T> constexpr T ltoh (T v) { return bswap (v); }
|
|
#else
|
|
template <typename T> constexpr T hton (T v) { return bswap (v); }
|
|
template <typename T> constexpr T ntoh (T v) { return bswap (v); }
|
|
|
|
template <typename T> constexpr T htob (T v) { return bswap (v); }
|
|
template <typename T> constexpr T htol (T v) { return v; }
|
|
|
|
template <typename T> constexpr T btoh (T v) { return bswap (v); }
|
|
template <typename T> constexpr T ltoh (T v) { return v; }
|
|
#endif
|
|
|
|
//-------------------------------------------------------------------------
|
|
struct from_endian {
|
|
explicit 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");
|
|
|
|
union {
|
|
typename sized_type<T>::sint sint;
|
|
typename sized_type<T>::uint uint;
|
|
};
|
|
|
|
if (std::is_signed<T>::value)
|
|
sint = v;
|
|
else
|
|
uint = v;
|
|
|
|
uint = (src == endian::LITTLE) ? ltoh (uint) : btoh (uint);
|
|
|
|
if (std::is_signed<T>::value)
|
|
return T (sint);
|
|
else
|
|
return T (uint);
|
|
}
|
|
|
|
endian src;
|
|
};
|
|
}
|
|
#endif
|