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Annotation of embedaddon/rsync/byteorder.h, revision 1.1.1.1

1.1       misho       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: #undef AVOID_BYTEORDER_INLINE
                     23: 
                     24: /* We know that the x86 can handle misalignment and has the same
                     25:  * byte order (LSB-first) as the 32-bit numbers we transmit. */
                     26: #ifdef __i386__
                     27: #define CAREFUL_ALIGNMENT 0
                     28: #endif
                     29: 
                     30: #ifndef CAREFUL_ALIGNMENT
                     31: #define CAREFUL_ALIGNMENT 1
                     32: #endif
                     33: 
                     34: #define CVAL(buf,pos) (((unsigned char *)(buf))[pos])
                     35: #define UVAL(buf,pos) ((uint32)CVAL(buf,pos))
                     36: 
                     37: #if CAREFUL_ALIGNMENT
                     38: 
                     39: #define PVAL(buf,pos) (UVAL(buf,pos)|UVAL(buf,(pos)+1)<<8)
                     40: #define IVAL(buf,pos) (PVAL(buf,pos)|PVAL(buf,(pos)+2)<<16)
                     41: #define SSVALX(buf,pos,val) (CVAL(buf,pos)=(val)&0xFF,CVAL(buf,pos+1)=(val)>>8)
                     42: #define SIVALX(buf,pos,val) (SSVALX(buf,pos,val&0xFFFF),SSVALX(buf,pos+2,val>>16))
                     43: #define SIVAL(buf,pos,val) SIVALX((buf),(pos),((uint32)(val)))
                     44: 
                     45: #define IVALu(buf,pos) IVAL(buf,pos)
                     46: #define SIVALu(buf,pos,val) SIVAL(buf,pos,val)
                     47: 
                     48: #else /* !CAREFUL_ALIGNMENT */
                     49: 
                     50: /* This handles things for architectures like the 386 that can handle alignment errors.
                     51:  * WARNING: This section is dependent on the length of an int32 (and thus a uint32)
                     52:  * being correct (4 bytes)!  Set CAREFUL_ALIGNMENT if it is not. */
                     53: 
                     54: # ifdef AVOID_BYTEORDER_INLINE
                     55: 
                     56: #define IVAL(buf,pos) (*(uint32 *)((char *)(buf) + (pos)))
                     57: #define SIVAL(buf,pos,val) IVAL(buf,pos)=((uint32)(val))
                     58: 
                     59: #define IVALu(buf,pos) IVAL(buf,pos)
                     60: #define SIVALu(buf,pos,val) SIVAL(buf,pos,val)
                     61: 
                     62: # else /* !AVOID_BYTEORDER_INLINE */
                     63: 
                     64: static inline uint32
                     65: IVALu(const uchar *buf, int pos)
                     66: {
                     67:        union {
                     68:                const uchar *b;
                     69:                const uint32 *num;
                     70:        } u;
                     71:        u.b = buf + pos;
                     72:        return *u.num;
                     73: }
                     74: 
                     75: static inline void
                     76: SIVALu(uchar *buf, int pos, uint32 val)
                     77: {
                     78:        union {
                     79:                uchar *b;
                     80:                uint32 *num;
                     81:        } u;
                     82:        u.b = buf + pos;
                     83:        *u.num = val;
                     84: }
                     85: 
                     86: static inline uint32
                     87: IVAL(const char *buf, int pos)
                     88: {
                     89:        return IVALu((uchar*)buf, pos);
                     90: }
                     91: 
                     92: static inline void
                     93: SIVAL(char *buf, int pos, uint32 val)
                     94: {
                     95:        SIVALu((uchar*)buf, pos, val);
                     96: }
                     97: 
                     98: # endif /* !AVOID_BYTEORDER_INLINE */
                     99: 
                    100: #endif /* !CAREFUL_ALIGNMENT */