byteorder.h

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/*
 * Branched from Samba project Subversion repository, version #2:
 *  http://websvn.samba.org/cgi-bin/viewcvs.cgi/trunk/source/include/byteorder.h
 *
 * Unix SMB/CIFS implementation.
 * SMB Byte handling
 *
 * Copyright (C) 2005 Timothy D. Morgan
 * Copyright (C) 1992-1998 Andrew Tridgell 
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 3 of the License.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * $Id: byteorder.h 168 2010-03-03 00:08:42Z tim $
 */

#ifndef _BYTEORDER_H
#define _BYTEORDER_H

#undef CAREFUL_ALIGNMENT

/* we know that the 386 can handle misalignment and has the "right" 
   byteorder */
#ifdef __i386__
#define CAREFUL_ALIGNMENT 0
#endif

#ifndef CAREFUL_ALIGNMENT
#define CAREFUL_ALIGNMENT 1
#endif

#define CVAL(buf,pos) ((unsigned)(((const unsigned char *)(buf))[pos]))
#define CVAL_NC(buf,pos) (((unsigned char *)(buf))[pos]) /* Non-const version of CVAL */
#define PVAL(buf,pos) (CVAL(buf,pos))
#define SCVAL(buf,pos,val) (CVAL_NC(buf,pos) = (val))


#if CAREFUL_ALIGNMENT

#define SVAL(buf,pos) (PVAL(buf,pos)|PVAL(buf,(pos)+1)<<8)
#define IVAL(buf,pos) (SVAL(buf,pos)|SVAL(buf,(pos)+2)<<16)
#define SSVALX(buf,pos,val) (CVAL_NC(buf,pos)=(unsigned char)((val)&0xFF),CVAL_NC(buf,pos+1)=(unsigned char)((val)>>8))
#define SIVALX(buf,pos,val) (SSVALX(buf,pos,val&0xFFFF),SSVALX(buf,pos+2,val>>16))
#define SVALS(buf,pos) ((int16_t)SVAL(buf,pos))
#define IVALS(buf,pos) ((int32_t)IVAL(buf,pos))
#define SSVAL(buf,pos,val) SSVALX((buf),(pos),((uint16_t)(val)))
#define SIVAL(buf,pos,val) SIVALX((buf),(pos),((uint32_t)(val)))
#define SSVALS(buf,pos,val) SSVALX((buf),(pos),((int16_t)(val)))
#define SIVALS(buf,pos,val) SIVALX((buf),(pos),((int32_t)(val)))

#else /* CAREFUL_ALIGNMENT */

/* this handles things for architectures like the 386 that can handle
   alignment errors */
/*
   WARNING: This section is dependent on the length of int16_t and int32_t
   being correct 
*/

/* get single value from an SMB buffer */
#define SVAL(buf,pos) (*(const uint16_t *)((const char *)(buf) + (pos)))
#define SVAL_NC(buf,pos) (*(uint16_t *)((char *)(buf) + (pos))) /* Non const version of above. */
#define IVAL(buf,pos) (*(const uint32_t *)((const char *)(buf) + (pos)))
#define IVAL_NC(buf,pos) (*(uint32_t *)((char *)(buf) + (pos))) /* Non const version of above. */
#define SVALS(buf,pos) (*(const int16_t *)((const char *)(buf) + (pos)))
#define SVALS_NC(buf,pos) (*(int16_t *)((char *)(buf) + (pos))) /* Non const version of above. */
#define IVALS(buf,pos) (*(const int32_t *)((const char *)(buf) + (pos)))
#define IVALS_NC(buf,pos) (*(int32_t *)((char *)(buf) + (pos))) /* Non const version of above. */

/* store single value in an SMB buffer */
#define SSVAL(buf,pos,val) SVAL_NC(buf,pos)=((uint16_t)(val))
#define SIVAL(buf,pos,val) IVAL_NC(buf,pos)=((uint32_t)(val))
#define SSVALS(buf,pos,val) SVALS_NC(buf,pos)=((int16_t)(val))
#define SIVALS(buf,pos,val) IVALS_NC(buf,pos)=((int32_t)(val))

#endif /* CAREFUL_ALIGNMENT */

/* now the reverse routines - these are used in nmb packets (mostly) */
#define SREV(x) ((((x)&0xFF)<<8) | (((x)>>8)&0xFF))
#define IREV(x) ((SREV(x)<<16) | (SREV((x)>>16)))

#define RSVAL(buf,pos) SREV(SVAL(buf,pos))
#define RSVALS(buf,pos) SREV(SVALS(buf,pos))
#define RIVAL(buf,pos) IREV(IVAL(buf,pos))
#define RIVALS(buf,pos) IREV(IVALS(buf,pos))
#define RSSVAL(buf,pos,val) SSVAL(buf,pos,SREV(val))
#define RSSVALS(buf,pos,val) SSVALS(buf,pos,SREV(val))
#define RSIVAL(buf,pos,val) SIVAL(buf,pos,IREV(val))
#define RSIVALS(buf,pos,val) SIVALS(buf,pos,IREV(val))

/* Alignment macros. */
#define ALIGN4(p,base) ((p) + ((4 - (PTR_DIFF((p), (base)) & 3)) & 3))
#define ALIGN2(p,base) ((p) + ((2 - (PTR_DIFF((p), (base)) & 1)) & 1))

#endif /* _BYTEORDER_H */