text: #ifndef _LINUX_BYTEORDER_GENERIC_H
  #define _LINUX_BYTEORDER_GENERIC_H
  
  /*
   * linux/byteorder_generic.h
   * Generic Byte-reordering support
   *
   * Francois-Rene Rideau <fare@tunes.org> 19970707
   *    gathered all the good ideas from all asm-foo/byteorder.h into one file,
   *    cleaned them up.
   *    I hope it is compliant with non-GCC compilers.
   *    I decided to put __BYTEORDER_HAS_U64__ in byteorder.h,
   *    because I wasn't sure it would be ok to put it in types.h
   *    Upgraded it to 2.1.43
   * Francois-Rene Rideau <fare@tunes.org> 19971012
   *    Upgraded it to 2.1.57
   *    to please Linus T., replaced huge #ifdef's between little/big endian
   *    by nestedly #include'd files.
   * Francois-Rene Rideau <fare@tunes.org> 19971205
   *    Made it to 2.1.71; now a facelift:
   *    Put files under include/linux/byteorder/
   *    Split swab from generic support.
   *
   * TODO:
   *   = Regular kernel maintainers could also replace all these manual
   *    byteswap macros that remain, disseminated among drivers,
   *    after some grep or the sources...
   *   = Linus might want to rename all these macros and files to fit his taste,
   *    to fit his personal naming scheme.
   *   = it seems that a few drivers would also appreciate
   *    nybble swapping support...
   *   = every architecture could add their byteswap macro in asm/byteorder.h
   *    see how some architectures already do (i386, alpha, ppc, etc)
   *   = cpu_to_beXX and beXX_to_cpu might some day need to be well
   *    distinguished throughout the kernel. This is not the case currently,
   *    since little endian, big endian, and pdp endian machines needn't it.
   *    But this might be the case for, say, a port of Linux to 20/21 bit
   *    architectures (and F21 Linux addict around?).
   */
  
  /*
   * The following macros are to be defined by <asm/byteorder.h>:
   *
   * Conversion of long and short int between network and host format
   *	ntohl(__u32 x)
   *	ntohs(__u16 x)
   *	htonl(__u32 x)
   *	htons(__u16 x)
   * It seems that some programs (which? where? or perhaps a standard? POSIX?)
   * might like the above to be functions, not macros (why?).
   * if that's true, then detect them, and take measures.
   * Anyway, the measure is: define only ___ntohl as a macro instead,
   * and in a separate file, have
   * unsigned long inline ntohl(x){return ___ntohl(x);}
   *
   * The same for constant arguments
   *	__constant_ntohl(__u32 x)
   *	__constant_ntohs(__u16 x)
   *	__constant_htonl(__u32 x)
   *	__constant_htons(__u16 x)
   *
   * Conversion of XX-bit integers (16- 32- or 64-)
   * between native CPU format and little/big endian format
   * 64-bit stuff only defined for proper architectures
   *	cpu_to_[bl]eXX(__uXX x)
   *	[bl]eXX_to_cpu(__uXX x)
   *
   * The same, but takes a pointer to the value to convert
   *	cpu_to_[bl]eXXp(__uXX x)
   *	[bl]eXX_to_cpup(__uXX x)
   *
   * The same, but change in situ
   *	cpu_to_[bl]eXXs(__uXX x)
   *	[bl]eXX_to_cpus(__uXX x)
   *
   * See asm-foo/byteorder.h for examples of how to provide
   * architecture-optimized versions
   *
   */
  
  
  #if defined(__KERNEL__)
  /*
   * inside the kernel, we can use nicknames;
   * outside of it, we must avoid POSIX namespace pollution...
   */
  #define cpu_to_le64 __cpu_to_le64
  #define le64_to_cpu __le64_to_cpu
  #define cpu_to_le32 __cpu_to_le32
  #define le32_to_cpu __le32_to_cpu
  #define cpu_to_le16 __cpu_to_le16
  #define le16_to_cpu __le16_to_cpu
  #define cpu_to_be64 __cpu_to_be64
  #define be64_to_cpu __be64_to_cpu
  #define cpu_to_be32 __cpu_to_be32
  #define be32_to_cpu __be32_to_cpu
  #define cpu_to_be16 __cpu_to_be16
  #define be16_to_cpu __be16_to_cpu
  #define cpu_to_le64p __cpu_to_le64p
  #define le64_to_cpup __le64_to_cpup
  #define cpu_to_le32p __cpu_to_le32p
  #define le32_to_cpup __le32_to_cpup
  #define cpu_to_le16p __cpu_to_le16p
  #define le16_to_cpup __le16_to_cpup
  #define cpu_to_be64p __cpu_to_be64p
  #define be64_to_cpup __be64_to_cpup
  #define cpu_to_be32p __cpu_to_be32p
  #define be32_to_cpup __be32_to_cpup
  #define cpu_to_be16p __cpu_to_be16p
  #define be16_to_cpup __be16_to_cpup
  #define cpu_to_le64s __cpu_to_le64s
  #define le64_to_cpus __le64_to_cpus
  #define cpu_to_le32s __cpu_to_le32s
  #define le32_to_cpus __le32_to_cpus
  #define cpu_to_le16s __cpu_to_le16s
  #define le16_to_cpus __le16_to_cpus
  #define cpu_to_be64s __cpu_to_be64s
  #define be64_to_cpus __be64_to_cpus
  #define cpu_to_be32s __cpu_to_be32s
  #define be32_to_cpus __be32_to_cpus
  #define cpu_to_be16s __cpu_to_be16s
  #define be16_to_cpus __be16_to_cpus
  #endif
  
  
  /*
   * Handle ntohl and suches. These have various compatibility
   * issues - like we want to give the prototype even though we
   * also have a macro for them in case some strange program
   * wants to take the address of the thing or something..
   *
   * Note that these used to return a "long" in libc5, even though
   * long is often 64-bit these days.. Thus the casts.
   *
   * They have to be macros in order to do the constant folding
   * correctly - if the argument passed into a inline function
   * it is no longer constant according to gcc..
   */
  
  #undef ntohl
  #undef ntohs
  #undef htonl
  #undef htons
  
  /*
   * Do the prototypes. Somebody might want to take the
   * address or some such sick thing..
   */
  #if defined(__KERNEL__) || (defined(__GLIBC__) && __GLIBC__ >= 2)
  extern __u32			ntohl(__u32);
  extern __u32			htonl(__u32);
  #else
  extern unsigned long int	ntohl(unsigned long int);
  extern unsigned long int	htonl(unsigned long int);
  #endif
  extern unsigned short int	ntohs(unsigned short int);
  extern unsigned short int	htons(unsigned short int);
  
  
  #if defined(__GNUC__) && (__GNUC__ >= 2) && defined(__OPTIMIZE__) && !defined(__STRICT_ANSI__)
  
  #define ___htonl(x) __cpu_to_be32(x)
  #define ___htons(x) __cpu_to_be16(x)
  #define ___ntohl(x) __be32_to_cpu(x)
  #define ___ntohs(x) __be16_to_cpu(x)
  
  #if defined(__KERNEL__) || (defined(__GLIBC__) && __GLIBC__ >= 2)
  #define htonl(x) ___htonl(x)
  #define ntohl(x) ___ntohl(x)
  #else
  #define htonl(x) ((unsigned long)___htonl(x))
  #define ntohl(x) ((unsigned long)___ntohl(x))
  #endif
  #define htons(x) ___htons(x)
  #define ntohs(x) ___ntohs(x)
  
  #endif /* OPTIMIZE */
  
  
  #endif /* _LINUX_BYTEORDER_GENERIC_H */
  