WDL/wdlendian.h

   1 /*
   2   WDL - wdlendian.h
   3   (c) Theo Niessink 2011
   4   <http://www.taletn.com/>
   5
   6   This software is provided 'as-is', without any express or implied
   7   warranty. In no event will the authors be held liable for any damages
   8   arising from the use of this software.
   9
  10   Permission is granted to anyone to use this software for any purpose,
  11   including commercial applications, and to alter it and redistribute it
  12   freely, subject to the following restrictions:
  13
  14   1. The origin of this software must not be misrepresented; you must not
  15      claim that you wrote the original software. If you use this software
  16      in a product, an acknowledgment in the product documentation would be
  17      appreciated but is not required.
  18   2. Altered source versions must be plainly marked as such, and must not be
  19      misrepresented as being the original software.
  20   3. This notice may not be removed or altered from any source distribution.
  21
  22
  23   This file provides macros and functions for converting integer and
  24   floating point data types from native (host) endian to little or big
  25   endian format, and vice versa.
  26
  27 */
  28
  29
  30 #ifndef _WDL_ENDIAN_H_
  31 #define _WDL_ENDIAN_H_
  32
  33
  34 #include "wdltypes.h"
  35
  36 typedef union { float  f; unsigned int int32; } WDL_EndianFloat;
  37 typedef union { double f; WDL_UINT64   int64; } WDL_EndianDouble;
  38
  39 #ifdef __cplusplus
  40         #define WDL_ENDIAN_INLINE inline
  41 #elif defined(_MSC_VER)
  42         #define WDL_ENDIAN_INLINE __inline
  43 #else
  44         #define WDL_ENDIAN_INLINE
  45 #endif
  46
  47
  48 // Windows
  49 #ifdef _WIN32
  50 #define WDL_LITTLE_ENDIAN
  51
  52 // Mac OS X
  53 #elif defined(__APPLE__)
  54 #if __LITTLE_ENDIAN__ // Intel
  55         #define WDL_LITTLE_ENDIAN
  56 #elif __BIG_ENDIAN__ // PowerPC
  57         #define WDL_BIG_ENDIAN
  58 #else
  59         #error Unknown endian
  60 #endif
  61
  62 // GNU C (v4.6 or later?)
  63 #elif __GNUC__ && defined(__BYTE_ORDER__)
  64 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
  65         #define WDL_LITTLE_ENDIAN
  66 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
  67         #define WDL_BIG_ENDIAN
  68 #else
  69         #error Unsupported endian
  70 #endif
  71 #if __FLOAT_WORD_ORDER__ != __BYTE_ORDER__
  72         #error Unsupported float endian
  73 #endif
  74
  75 // GNU C, Intel C++
  76 #elif defined(__i386) || defined(__i386__) || defined(i386)
  77 #define WDL_LITTLE_ENDIAN
  78
  79 // Intel C++
  80 #elif defined(__x86_64) || defined(__x86_64__)
  81 #define WDL_LITTLE_ENDIAN
  82
  83 #else
  84 #error Unknown endian
  85 #endif
  86
  87
  88 // Microsoft C
  89 #ifdef _MSC_VER
  90 #include <intrin.h>
  91 #define WDL_bswap16(x) _byteswap_ushort(x)
  92 #define WDL_bswap32(x) _byteswap_ulong(x)
  93 #define WDL_bswap64(x) _byteswap_uint64(x)
  94
  95 #elif defined(__APPLE__)
  96   #include "TargetConditionals.h"
  97   #if defined(TARGET_OS_IPHONE) | defined(TARGET_IPHONE_SIMULATOR)
  98     #include <libkern/OSByteOrder.h>
  99
 100     // iOS
 101     #define WDL_bswap16(x) OSSwapInt16(x)
 102     #define WDL_bswap32(x) OSSwapInt32(x)
 103     #define WDL_bswap64(x) OSSwapInt64(x)
 104
 105   // Mac OS X (v10.0 and later)
 106   #elif defined(TARGET_OS_MAC)
 107     #include <CoreServices/CoreServices.h>
 108
 109     #define WDL_bswap16(x) Endian16_Swap(x)
 110     #define WDL_bswap32(x) Endian32_Swap(x)
 111     #define WDL_bswap64(x) Endian64_Swap(x) // (Thread-safe on) v10.3 and later (?)
 112 #endif
 113
 114
 115 // GNU C
 116 #elif __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
 117 #define WDL_bswap32(x) __builtin_bswap32(x)
 118 #define WDL_bswap64(x) __builtin_bswap64(x)
 119
 120 // Linux
 121 #elif defined(__linux) || defined(__linux__) || defined(linux)
 122 #include <endian.h>
 123 #define WDL_bswap16(x) bswap16(x)
 124 #define WDL_bswap32(x) bswap32(x)
 125 #define WDL_bswap64(x) bswap64(x)
 126
 127 #endif // WDL_bswapXX
 128
 129 // If none of the supported intrinsics were found, then revert to generic C
 130 // byte swap functions.
 131 #ifndef WDL_bswap16
 132 static WDL_ENDIAN_INLINE unsigned short WDL_bswap16(const unsigned short int16)
 133 {
 134         return int16 >> 8 |
 135                int16 << 8;
 136 }
 137 #endif
 138
 139 #ifndef WDL_bswap32
 140 static WDL_ENDIAN_INLINE unsigned int WDL_bswap32(const unsigned int int32)
 141 {
 142         return int32 >> 24 |
 143                int32 >> 8  & 0x0000FF00 |
 144                int32 << 8  & 0x00FF0000 |
 145                int32 << 24;
 146 }
 147 #endif
 148
 149 #ifndef WDL_bswap64
 150 static WDL_ENDIAN_INLINE WDL_UINT64 WDL_bswap64(const WDL_UINT64 int64)
 151 {
 152         return int64 >> 56 |
 153                int64 >> 40 & 0x000000000000FF00ULL |
 154                int64 >> 24 & 0x0000000000FF0000ULL |
 155                int64 >> 8  & 0x00000000FF000000ULL |
 156                int64 << 8  & 0x000000FF00000000ULL |
 157                int64 << 24 & 0x0000FF0000000000ULL |
 158                int64 << 40 & 0x00FF000000000000ULL |
 159                int64 << 56;
 160 }
 161 #endif
 162
 163
 164 // Int types
 165
 166 #if defined(WDL_LITTLE_ENDIAN)
 167
 168         #define WDL_bswap16_if_le(x) WDL_bswap16(x)
 169         #define WDL_bswap32_if_le(x) WDL_bswap32(x)
 170         #define WDL_bswap64_if_le(x) WDL_bswap64(x)
 171         #define WDL_bswap16_if_be(x) ((unsigned short)(x))
 172         #define WDL_bswap32_if_be(x) ((unsigned int)(x))
 173         #define WDL_bswap64_if_be(x) ((WDL_UINT64)(x))
 174
 175         // Wrappers that convert a variable in-place, or generate no code if
 176         // conversion is not necessary. Beware to only feed variables to these
 177         // macros, so no fancy things like WDL_BSWAP32_IF_LE(x + y) or
 178         // WDL_BSWAP32_IF_LE(x++). Note that these macros only change the type
 179         // to unsigned if conversion is actually necessary.
 180         #define WDL_BSWAP16_IF_LE(x) (x = WDL_bswap16(x))
 181         #define WDL_BSWAP32_IF_LE(x) (x = WDL_bswap32(x))
 182         #define WDL_BSWAP64_IF_LE(x) (x = WDL_bswap64(x))
 183         #define WDL_BSWAP16_IF_BE(x) ((void)0)
 184         #define WDL_BSWAP32_IF_BE(x) ((void)0)
 185         #define WDL_BSWAP64_IF_BE(x) ((void)0)
 186
 187 #else // #elif defined(WDL_BIG_ENDIAN)
 188
 189         #define WDL_bswap16_if_be(x) WDL_bswap16(x)
 190         #define WDL_bswap32_if_be(x) WDL_bswap32(x)
 191         #define WDL_bswap64_if_be(x) WDL_bswap64(x)
 192         #define WDL_bswap16_if_le(x) ((unsigned short)(x))
 193         #define WDL_bswap32_if_le(x) ((unsigned int)(x))
 194         #define WDL_bswap64_if_le(x) ((WDL_UINT64)(x))
 195
 196         // In-place wrappers (see notes above)
 197         #define WDL_BSWAP16_IF_BE(x) (x = WDL_bswap16(x))
 198         #define WDL_BSWAP32_IF_BE(x) (x = WDL_bswap32(x))
 199         #define WDL_BSWAP64_IF_BE(x) (x = WDL_bswap64(x))
 200         #define WDL_BSWAP16_IF_LE(x) ((void)0)
 201         #define WDL_BSWAP32_IF_LE(x) ((void)0)
 202         #define WDL_BSWAP64_IF_LE(x) ((void)0)
 203
 204 #endif // WDL_bswapXX_if_YY
 205
 206
 207 // C++ auto-typed wrappers
 208
 209 #ifdef __cplusplus
 210
 211 static WDL_ENDIAN_INLINE unsigned short WDL_bswap_if_le(unsigned short int16) { return WDL_bswap16_if_le(int16); }
 212 static WDL_ENDIAN_INLINE signed   short WDL_bswap_if_le(signed   short int16) { return WDL_bswap16_if_le(int16); }
 213 static WDL_ENDIAN_INLINE unsigned int   WDL_bswap_if_le(unsigned int   int32) { return WDL_bswap32_if_le(int32); }
 214 static WDL_ENDIAN_INLINE signed   int   WDL_bswap_if_le(signed   int   int32) { return WDL_bswap32_if_le(int32); }
 215 static WDL_ENDIAN_INLINE WDL_UINT64     WDL_bswap_if_le(WDL_UINT64     int64) { return WDL_bswap64_if_le(int64); }
 216 static WDL_ENDIAN_INLINE WDL_INT64      WDL_bswap_if_le(WDL_INT64      int64) { return WDL_bswap64_if_le(int64); }
 217
 218 static WDL_ENDIAN_INLINE unsigned short WDL_bswap_if_be(unsigned short int16) { return WDL_bswap16_if_be(int16); }
 219 static WDL_ENDIAN_INLINE signed   short WDL_bswap_if_be(signed   short int16) { return WDL_bswap16_if_be(int16); }
 220 static WDL_ENDIAN_INLINE unsigned int   WDL_bswap_if_be(unsigned int   int32) { return WDL_bswap32_if_be(int32); }
 221 static WDL_ENDIAN_INLINE signed   int   WDL_bswap_if_be(signed   int   int32) { return WDL_bswap32_if_be(int32); }
 222 static WDL_ENDIAN_INLINE WDL_UINT64     WDL_bswap_if_be(WDL_UINT64     int64) { return WDL_bswap64_if_be(int64); }
 223 static WDL_ENDIAN_INLINE WDL_INT64      WDL_bswap_if_be(WDL_INT64      int64) { return WDL_bswap64_if_be(int64); }
 224
 225 // Auto-typed in-place wrappers (see notes above)
 226 #ifdef WDL_LITTLE_ENDIAN
 227         #define WDL_BSWAP_IF_LE(x) (x = WDL_bswap_if_le(x))
 228         #define WDL_BSWAP_IF_BE(x) ((void)0)
 229 #else // #elif defined(WDL_BIG_ENDIAN)
 230         #define WDL_BSWAP_IF_BE(x) (x = WDL_bswap_if_be(x))
 231         #define WDL_BSWAP_IF_LE(x) ((void)0)
 232 #endif
 233
 234
 235 // Map floating point types to int types.
 236
 237 #if defined(WDL_LITTLE_ENDIAN)
 238         #define __WDL_bswapf_if_a WDL_bswapf_if_le
 239         #define __WDL_bswapf_if_b WDL_bswapf_if_be
 240 #else // #elif defined(WDL_BIG_ENDIAN)
 241         #define __WDL_bswapf_if_a WDL_bswapf_if_be
 242         #define __WDL_bswapf_if_b WDL_bswapf_if_le
 243 #endif
 244
 245 static WDL_ENDIAN_INLINE unsigned int __WDL_bswapf_if_a(const float        f)     { return WDL_bswap32(*(const unsigned int*)&f); }
 246 static WDL_ENDIAN_INLINE WDL_UINT64   __WDL_bswapf_if_a(const double       f)     { return WDL_bswap64(*(const WDL_UINT64  *)&f); }
 247
 248 static WDL_ENDIAN_INLINE float        __WDL_bswapf_if_a(const unsigned int int32)
 249 {
 250         const unsigned int i = WDL_bswap32(int32);
 251         return *(const float*)&i;
 252 }
 253
 254 static WDL_ENDIAN_INLINE double       __WDL_bswapf_if_a(const WDL_UINT64   int64)
 255 {
 256         const WDL_UINT64 i = WDL_bswap64(int64);
 257         return *(const double*)&i;
 258 }
 259
 260 static WDL_ENDIAN_INLINE unsigned int __WDL_bswapf_if_b(const float        f)     { return *(const unsigned int*)&f; }
 261 static WDL_ENDIAN_INLINE WDL_UINT64   __WDL_bswapf_if_b(const double       f)     { return *(const WDL_UINT64  *)&f; }
 262 static WDL_ENDIAN_INLINE float        __WDL_bswapf_if_b(const unsigned int int32) { return *(const float       *)&int32; }
 263 static WDL_ENDIAN_INLINE double       __WDL_bswapf_if_b(const WDL_UINT64   int64) { return *(const double      *)&int64; }
 264
 265 #undef __WDL_bswapf_if_a
 266 #undef __WDL_bswapf_if_b
 267
 268 #endif // __cplusplus
 269
 270
 271 #endif // _WDL_ENDIAN_H_