byteorder.h

   1 /*
   2  * Simple byteorder handling.
   3  *
   4  * Copyright (C) 1992-1995 Andrew Tridgell
   5  * Copyright (C) 2007-2008 Wayne Davison
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 3 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, visit the http://fsf.org website.
  19  */
  20
  21 #undef CAREFUL_ALIGNMENT
  22
  23 /* We know that the x86 can handle misalignment and has the same
  24  * byte order (LSB-first) as the 32-bit numbers we transmit. */
  25 #ifdef __i386__
  26 #define CAREFUL_ALIGNMENT 0
  27 #endif
  28
  29 #ifndef CAREFUL_ALIGNMENT
  30 #define CAREFUL_ALIGNMENT 1
  31 #endif
  32
  33 #define CVAL(buf,pos) (((unsigned char *)(buf))[pos])
  34 #define UVAL(buf,pos) ((uint32)CVAL(buf,pos))
  35 #define SCVAL(buf,pos,val) (CVAL(buf,pos) = (val))
  36
  37 #if CAREFUL_ALIGNMENT
  38 #define PVAL(buf,pos) (UVAL(buf,pos)|UVAL(buf,(pos)+1)<<8)
  39 #define IVAL(buf,pos) (PVAL(buf,pos)|PVAL(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