endian: complete reimplementation
Old implementation was overly verbose. We can just rely on gcc builtins as we can't actually build on anything else anyway.
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87
endian.cpp
87
endian.cpp
@ -14,92 +14,7 @@
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* You should have received a copy of the GNU General Public License
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* along with libgim. If not, see <http://www.gnu.org/licenses/>.
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*
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* Copyright 2010 Danny Robson <danny@nerdcruft.net>
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* Copyright 2010-2014 Danny Robson <danny@nerdcruft.net>
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*/
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#include "endian.hpp"
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#include <cstdio>
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#include <type_traits>
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using std::is_fundamental;
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using std::is_unsigned;
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#ifdef WORDS_BIGENDIAN
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/* Big endian doesn't need swapping */
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template <typename T>
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T hton (T val) {
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static_assert (is_fundamental <T>(), "hton implementation assumes fundamental types");
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static_assert (is_unsigned <T>(), "hton implementation does not handle signed");
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return val;
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}
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template <typename T>
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T ntoh (T val) {
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static_assert (is_fundamental <T>(), "ntoh implementation assumes fundamental types");
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static_assert (is_unsigned <T>(), "ntoh implementation does not handle signed");
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return val;
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}
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template <> uint8_t hton ( uint8_t);
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template <> uint16_t hton (uint16_t);
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template <> uint32_t hton (uint32_t);
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template <> uint64_t hton (uint64_t);
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template <> uint8_t ntoh ( uint8_t);
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template <> uint16_t ntoh (uint16_t);
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template <> uint32_t ntoh (uint32_t);
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template <> uint64_t ntoh (uint64_t);
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#else
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static void
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byte_swap (uint8_t *restrict dst, uint8_t *restrict src, size_t len) {
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for (unsigned int i = 0; i < len; ++i)
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dst[len - i - 1] = src[i];
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}
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template <typename T>
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T
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hton (T i) {
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// Unsure if this will really be sensible for non-intrinsic types, or types larger than 8 bytes.
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static_assert (is_fundamental <T>::value, "hton implementation assumes fundamental types");
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static_assert (is_unsigned <T>::value, "hton implementation does not handle signed");
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T swapped;
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byte_swap (reinterpret_cast <uint8_t*>(&swapped),
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reinterpret_cast <uint8_t*>(&i),
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sizeof (T));
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return swapped;
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}
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template <typename T>
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T
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ntoh (T i) {
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// Unsure if this will really be sensible for non-intrinsic types, or types larger than 8 bytes.
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static_assert (is_fundamental <T>::value, "ntoh implementation assumes fundamental types");
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static_assert (is_unsigned <T>::value, "ntoh implementation does not handle signed");
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T swapped;
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byte_swap (reinterpret_cast <uint8_t*>(&swapped),
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reinterpret_cast <uint8_t*>(&i),
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sizeof (T));
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return swapped;
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}
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template <> uint8_t hton (uint8_t i) { return i; }
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template <> uint8_t ntoh (uint8_t i) { return i; }
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template uint16_t ntoh<uint16_t> (uint16_t);
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template uint32_t ntoh<uint32_t> (uint32_t);
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template uint64_t ntoh<uint64_t> (uint64_t);
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template uint16_t hton<uint16_t> (uint16_t);
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template uint32_t hton<uint32_t> (uint32_t);
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template uint64_t hton<uint64_t> (uint64_t);
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#endif
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79
endian.hpp
79
endian.hpp
@ -14,69 +14,54 @@
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* You should have received a copy of the GNU General Public License
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* along with libgim. If not, see <http://www.gnu.org/licenses/>.
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*
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* Copyright 2010 Danny Robson <danny@nerdcruft.net>
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* Copyright 2010-2014 Danny Robson <danny@nerdcruft.net>
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*/
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#ifndef __UTIL_ENDIAN_HPP
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#define __UTIL_ENDIAN_HPP
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#include "platform.hpp"
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#include <cstdint>
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enum {
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ENDIAN_BIG,
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ENDIAN_LITTLE
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};
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//-----------------------------------------------------------------------------
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template <typename T>
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constexpr T
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bswap (T);
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template <> constexpr uint8_t bswap ( uint8_t v) { return v; }
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template <> constexpr uint16_t bswap (uint16_t v) { return __builtin_bswap16 (v); }
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template <> constexpr uint32_t bswap (uint32_t v) { return __builtin_bswap32 (v); }
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template <> constexpr uint64_t bswap (uint64_t v) { return __builtin_bswap64 (v); }
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constexpr uint8_t hton (uint8_t h) { return h; }
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constexpr uint8_t ntoh (uint8_t n) { return n; }
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constexpr uint16_t hton (uint16_t h) {
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return ((h & 0xFF00) >> 8) |
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((h & 0x00FF) << 8);
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//-----------------------------------------------------------------------------
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template <typename T>
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constexpr T
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identity (T &&v) {
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return v;
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}
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constexpr uint16_t ntoh (uint16_t n)
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{ return hton (n); }
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//-----------------------------------------------------------------------------
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#if defined(WORDS_BIGENDIAN)
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template <typename T> constexpr T hton (T v) { return v; }
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template <typename T> constexpr T ntoh (T v) { return v; }
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constexpr uint32_t hton (uint32_t h) {
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#if defined(COMPILER_GCC)
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return __builtin_bswap32 (h);
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template <typename T> constexpr T htob (T v) { return v; }
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template <typename T> constexpr T htol (T v) { return bswap (v); }
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template <typename T> constexpr T btoh (T v) { return v; }
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template <typename T> constexpr T ltoh (T v) { return bswap (v); }
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#else
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return (h & 0xFF000000U) >> 24 |
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(h & 0x00FF0000U) >> 8 |
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(h & 0x0000FF00U) << 8 |
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(h & 0x000000FFU) << 24;
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template <typename T> constexpr T hton (T v) { return bswap (v); }
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template <typename T> constexpr T ntoh (T v) { return bswap (v); }
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template <typename T> constexpr T htob (T v) { return bswap (v); }
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template <typename T> constexpr T htol (T v) { return v; }
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template <typename T> constexpr T btoh (T v) { return bswap (v); }
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template <typename T> constexpr T ltoh (T v) { return v; }
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#endif
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}
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constexpr uint32_t ntoh (uint32_t n)
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{ return hton (n); }
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constexpr uint64_t hton (uint64_t h) {
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#if defined(COMPILER_GCC)
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return __builtin_bswap64 (h);
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#else
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return (h & 0xFF00000000000000UL) >> 56 |
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(h & 0x00FF000000000000UL) >> 40 |
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(h & 0x0000FF0000000000UL) >> 24 |
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(h & 0x000000FF00000000UL) >> 8 |
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(h & 0x00000000FF000000UL) << 8 |
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(h & 0x0000000000FF0000UL) << 24 |
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(h & 0x000000000000FF00UL) << 40 |
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(h & 0x00000000000000FFUL) << 56;
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#endif
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}
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constexpr uint64_t ntoh (uint64_t n)
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{ return hton (n); }
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#endif
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