byteorder.h

   1 /*
   2    simple byteorder handling
   3    Copyright (C) Andrew Tridgell 1992-1995
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software
  17    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18 */
  19
  20 #undef CAREFUL_ALIGNMENT
  21
  22 /* we know that the x86 can handle misalignment and has the "right"
  23    byteorder */
  24 #ifdef __i386__
  25 #define CAREFUL_ALIGNMENT 0
  26 #endif
  27
  28 #ifndef CAREFUL_ALIGNMENT
  29 #define CAREFUL_ALIGNMENT 1
  30 #endif
  31
  32 #define CVAL(buf,pos) (((unsigned char *)(buf))[pos])
  33 #define PVAL(buf,pos) ((unsigned)CVAL(buf,pos))
  34 #define SCVAL(buf,pos,val) (CVAL(buf,pos) = (val))
  35
  36
  37 #if CAREFUL_ALIGNMENT
  38 #define SVAL(buf,pos) (PVAL(buf,pos)|PVAL(buf,(pos)+1)<<8)
  39 #define IVAL(buf,pos) (SVAL(buf,pos)|SVAL(buf,(pos)+2)<<16)
  40 #define SSVALX(buf,pos,val) (CVAL(buf,pos)=(val)&0xFF,CVAL(buf,pos+1)=(val)>>8)
  41 #define SIVALX(buf,pos,val) (SSVALX(buf,pos,val&0xFFFF),SSVALX(buf,pos+2,val>>16))
  42 #define SIVAL(buf,pos,val) SIVALX((buf),(pos),((uint32)(val)))
  43 #else
  44 /* this handles things for architectures like the 386 that can handle
  45    alignment errors */
  46 /*
  47    WARNING: This section is dependent on the length of int32
  48    being correct. set CAREFUL_ALIGNMENT if it is not.
  49 */
  50 #define IVAL(buf,pos) (*(uint32 *)((char *)(buf) + (pos)))
  51 #define SIVAL(buf,pos,val) IVAL(buf,pos)=((uint32)(val))
  52 #endif
  53
  54