include/mruby/endian.h

   1 /**
   2 ** @file mruby/endian.h - detect endian-ness
   3 **
   4 ** See Copyright Notice in mruby.h
   5 */
   6
   7 #ifndef MRUBY_ENDIAN_H
   8 #define MRUBY_ENDIAN_H
   9
  10 #include <limits.h>
  11
  12 MRB_BEGIN_DECL
  13
  14 #if !defined(BYTE_ORDER) && defined(__BYTE_ORDER__)
  15 # define BYTE_ORDER __BYTE_ORDER__
  16 #endif
  17 #if !defined(BIG_ENDIAN) && defined(__ORDER_BIG_ENDIAN__)
  18 # define BIG_ENDIAN __ORDER_BIG_ENDIAN__
  19 #endif
  20 #if !defined(LITTLE_ENDIAN) && defined(__ORDER_LITTLE_ENDIAN__)
  21 # define LITTLE_ENDIAN __ORDER_LITTLE_ENDIAN__
  22 #endif
  23
  24 #ifdef BYTE_ORDER
  25 # if BYTE_ORDER == BIG_ENDIAN
  26 #  define littleendian 0
  27 # elif BYTE_ORDER == LITTLE_ENDIAN
  28 #  define littleendian 1
  29 # endif
  30 #endif
  31 #ifndef littleendian
  32 /* can't distinguish endian in compile time */
  33 static inline int
  34 check_little_endian(void)
  35 {
  36   unsigned int n = 1;
  37   return (*(unsigned char *)&n == 1);
  38 }
  39 #  define littleendian check_little_endian()
  40 #endif
  41
  42 MRB_END_DECL
  43
  44 #endif  /* MRUBY_ENDIAN_H */