144 lines
3.1 KiB
C
144 lines
3.1 KiB
C
#ifndef _SYS_BYTEORDER_H
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#define _SYS_BYTEORDER_H
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/* Functions to convert `short' and `long' quantities from host byte order
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to (internet) network byte order (i.e. big-endian).
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Written by Ron Guilmette (rfg@ncd.com).
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This isn't actually used by GCC. It is installed by fixinc.svr4.
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For big-endian machines these functions are essentially no-ops.
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For little-endian machines, we define the functions using specialized
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asm sequences in cases where doing so yields better code (e.g. i386). */
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#if !defined (__GNUC__) && !defined (__GNUG__)
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#error You lose! This file is only useful with GNU compilers.
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#endif
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#ifdef __GNUC__
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#define __STATIC static
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#else
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#define __STATIC
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#endif
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#ifdef __STDC__
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__STATIC __inline__ unsigned long htonl (unsigned long);
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__STATIC __inline__ unsigned short htons (unsigned int);
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__STATIC __inline__ unsigned long ntohl (unsigned long);
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__STATIC __inline__ unsigned short ntohs (unsigned int);
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#endif /* defined (__STDC__) */
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#if defined (__i386__)
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/* Convert a host long to a network long. */
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__STATIC __inline__ unsigned long
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htonl (__arg)
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unsigned long __arg;
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{
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register unsigned long __result __asm__ ("%eax");
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__result = __arg;
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__asm__ ("xchgb %%ah, %%al\n\
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rorl $16, %%eax\n\
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xchgb %%ah, %%al\n\
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clc" : "=r" (__result) : "0" (__result));
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return __result;
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}
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/* Convert a host short to a network short. */
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__STATIC __inline__ unsigned short
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htons (__arg)
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unsigned int __arg;
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{
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register unsigned short __result __asm__ ("%eax");
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__result = __arg;
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__asm__ ("xchgb %%ah, %%al\n\
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clc" : "=r" (__result) : "0" (__result));
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return __result;
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}
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#elif ((defined (__i860__) && !defined (__i860_big_endian__)) \
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|| defined (__ns32k__) || defined (__vax__) \
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|| defined (__spur__) || defined (__arm__))
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/* For other little-endian machines, using C code is just as efficient as
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using assembly code. */
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/* Convert a host long to a network long. */
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__STATIC __inline__ unsigned long
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htonl (__arg)
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unsigned long __arg;
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{
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register unsigned long __result;
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__result = (__arg >> 24) & 0x000000ff;
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__result |= (__arg >> 8) & 0x0000ff00;
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__result |= (__arg << 8) & 0x00ff0000;
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__result |= (__arg << 24) & 0xff000000;
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return __result;
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}
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/* Convert a host short to a network short. */
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__STATIC __inline__ unsigned short
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htons (__arg)
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unsigned int __arg;
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{
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register unsigned short __result;
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__result = (__arg << 8) & 0xff00;
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__result |= (__arg >> 8) & 0x00ff;
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return __result;
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}
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#else /* must be a big-endian machine */
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/* Convert a host long to a network long. */
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__STATIC __inline__ unsigned long
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htonl (__arg)
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unsigned long __arg;
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{
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return __arg;
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}
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/* Convert a host short to a network short. */
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__STATIC __inline__ unsigned short
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htons (__arg)
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unsigned int __arg;
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{
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return __arg;
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}
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#endif /* big-endian */
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/* Convert a network long to a host long. */
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__STATIC __inline__ unsigned long
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ntohl (__arg)
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unsigned long __arg;
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{
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return htonl (__arg);
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}
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/* Convert a network short to a host short. */
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__STATIC __inline__ unsigned short
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ntohs (__arg)
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unsigned int __arg;
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{
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return htons (__arg);
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}
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#undef __STATIC
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#endif /* !defined (_SYS_BYTEORDER_H) */
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