common/include/byte-swapping.h

   1 /* nbdkit
   2  * Copyright Red Hat
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  * * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *
  11  * * Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  *
  15  * * Neither the name of Red Hat nor the names of its contributors may be
  16  * used to endorse or promote products derived from this software without
  17  * specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  22  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
  23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  26  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  27  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  28  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  29  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 /* The job of this header is to define macros (or functions) called
  34  * things like 'htobe32' and 'le64toh' which byte swap N-bit integers
  35  * between host representation, and little and big endian.  Also
  36  * bswap_16, bswap_32 and bswap_64 which simply swap endianness.
  37  *
  38  * The core code and plugins in nbdkit uses these names and relies on
  39  * this header to provide the platform-specific implementation.  On
  40  * GNU/Linux these are defined in <endian.h> and <byteswap.h> but
  41  * other platforms have other requirements.
  42  */
  43
  44 #ifndef NBDKIT_BYTE_SWAPPING_H
  45 #define NBDKIT_BYTE_SWAPPING_H
  46
  47 #ifdef HAVE_BYTESWAP_H
  48 #include <byteswap.h>
  49 #endif
  50
  51 #ifdef HAVE_ENDIAN_H
  52 #include <endian.h>
  53 #endif
  54
  55 #ifdef HAVE_SYS_ENDIAN_H
  56 #include <sys/endian.h>
  57 #endif
  58
  59 #ifdef __HAIKU__
  60 #include <ByteOrder.h>
  61 #define htobe16(x) B_HOST_TO_BENDIAN_INT16 (x)
  62 #define htole16(x) B_HOST_TO_LENDIAN_INT16 (x)
  63 #define be16toh(x) B_BENDIAN_TO_HOST_INT16 (x)
  64 #define le16toh(x) B_LENDIAN_TO_HOST_INT16 (x)
  65
  66 #define htobe32(x) B_HOST_TO_BENDIAN_INT32 (x)
  67 #define htole32(x) B_HOST_TO_LENDIAN_INT32 (x)
  68 #define be32toh(x) B_BENDIAN_TO_HOST_INT32 (x)
  69 #define le32toh(x) B_LENDIAN_TO_HOST_INT32 (x)
  70
  71 #define htobe64(x) B_HOST_TO_BENDIAN_INT64 (x)
  72 #define htole64(x) B_HOST_TO_LENDIAN_INT64 (x)
  73 #define be64toh(x) B_BENDIAN_TO_HOST_INT64 (x)
  74 #define le64toh(x) B_LENDIAN_TO_HOST_INT64 (x)
  75 #endif
  76
  77 /* If we didn't define bswap_16, bswap_32 and bswap_64 already above,
  78  * create macros.  GCC >= 4.8 and Clang have builtins.
  79  */
  80 #ifndef bswap_16
  81 #define bswap_16 __builtin_bswap16
  82 #endif
  83
  84 #ifndef bswap_32
  85 #define bswap_32 __builtin_bswap32
  86 #endif
  87
  88 #ifndef bswap_64
  89 #define bswap_64 __builtin_bswap64
  90 #endif
  91
  92 /* If we didn't define htobe* above then define them in terms of
  93  * bswap_* macros.
  94  */
  95 #ifndef htobe32
  96 # ifndef WORDS_BIGENDIAN /* little endian */
  97 #  define htobe16(x) bswap_16 (x)
  98 #  define htole16(x) (x)
  99 #  define be16toh(x) bswap_16 (x)
 100 #  define le16toh(x) (x)
 101
 102 #  define htobe32(x) bswap_32 (x)
 103 #  define htole32(x) (x)
 104 #  define be32toh(x) bswap_32 (x)
 105 #  define le32toh(x) (x)
 106
 107 #  define htobe64(x) bswap_64 (x)
 108 #  define htole64(x) (x)
 109 #  define be64toh(x) bswap_64 (x)
 110 #  define le64toh(x) (x)
 111
 112 # else /* big endian */
 113 #  define htobe16(x) (x)
 114 #  define htole16(x) bswap_16 (x)
 115 #  define be16toh(x) (x)
 116 #  define le16toh(x) bswap_16 (x)
 117
 118 #  define htobe32(x) (x)
 119 #  define htole32(x) bswap_32 (x)
 120 #  define be32toh(x) (x)
 121 #  define le32toh(x) bswap_32 (x)
 122
 123 #  define htobe64(x) (x)
 124 #  define htole64(x) bswap_64 (x)
 125 #  define be64toh(x) (x)
 126 #  define le64toh(x) bswap_64 (x)
 127 # endif
 128 #endif
 129
 130 #endif /* NBDKIT_BYTE_SWAPPING_H */