db2/include/db_swap.h

   1 /*-
   2  * See the file LICENSE for redistribution information.
   3  *
   4  * Copyright (c) 1996, 1997, 1998
   5  *      Sleepycat Software.  All rights reserved.
   6  */
   7 /*
   8  * Copyright (c) 1990, 1993, 1994
   9  *      The Regents of the University of California.  All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. All advertising materials mentioning features or use of this software
  20  *    must display the following acknowledgement:
  21  *      This product includes software developed by the University of
  22  *      California, Berkeley and its contributors.
  23  * 4. Neither the name of the University nor the names of its contributors
  24  *    may be used to endorse or promote products derived from this software
  25  *    without specific prior written permission.
  26  *
  27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  37  * SUCH DAMAGE.
  38  *
  39  *      @(#)db_swap.h   10.5 (Sleepycat) 4/10/98
  40  */
  41
  42 #ifndef _DB_SWAP_H_
  43 #define _DB_SWAP_H_
  44
  45 /*
  46  * Little endian <==> big endian 32-bit swap macros.
  47  *      M_32_SWAP       swap a memory location
  48  *      P_32_COPY       copy potentially unaligned 4 byte quantities
  49  *      P_32_SWAP       swap a referenced memory location
  50  */
  51 #define M_32_SWAP(a) {                                                  \
  52         u_int32_t _tmp;                                                 \
  53         _tmp = a;                                                       \
  54         ((u_int8_t *)&a)[0] = ((u_int8_t *)&_tmp)[3];                   \
  55         ((u_int8_t *)&a)[1] = ((u_int8_t *)&_tmp)[2];                   \
  56         ((u_int8_t *)&a)[2] = ((u_int8_t *)&_tmp)[1];                   \
  57         ((u_int8_t *)&a)[3] = ((u_int8_t *)&_tmp)[0];                   \
  58 }
  59 #define P_32_COPY(a, b) {                                               \
  60         ((u_int8_t *)b)[0] = ((u_int8_t *)a)[0];                        \
  61         ((u_int8_t *)b)[1] = ((u_int8_t *)a)[1];                        \
  62         ((u_int8_t *)b)[2] = ((u_int8_t *)a)[2];                        \
  63         ((u_int8_t *)b)[3] = ((u_int8_t *)a)[3];                        \
  64 }
  65 #define P_32_SWAP(a) {                                                  \
  66         u_int32_t _tmp;                                                 \
  67         P_32_COPY(a, &_tmp);                                            \
  68         ((u_int8_t *)a)[0] = ((u_int8_t *)&_tmp)[3];                    \
  69         ((u_int8_t *)a)[1] = ((u_int8_t *)&_tmp)[2];                    \
  70         ((u_int8_t *)a)[2] = ((u_int8_t *)&_tmp)[1];                    \
  71         ((u_int8_t *)a)[3] = ((u_int8_t *)&_tmp)[0];                    \
  72 }
  73
  74 /*
  75  * Little endian <==> big endian 16-bit swap macros.
  76  *      M_16_SWAP       swap a memory location
  77  *      P_16_COPY       copy potentially unaligned 2 byte quantities
  78  *      P_16_SWAP       swap a referenced memory location
  79  */
  80 #define M_16_SWAP(a) {                                                  \
  81         u_int16_t _tmp;                                                 \
  82         _tmp = (u_int16_t)a;                                            \
  83         ((u_int8_t *)&a)[0] = ((u_int8_t *)&_tmp)[1];                   \
  84         ((u_int8_t *)&a)[1] = ((u_int8_t *)&_tmp)[0];                   \
  85 }
  86 #define P_16_COPY(a, b) {                                               \
  87         ((u_int8_t *)b)[0] = ((u_int8_t *)a)[0];                        \
  88         ((u_int8_t *)b)[1] = ((u_int8_t *)a)[1];                        \
  89 }
  90 #define P_16_SWAP(a) {                                                  \
  91         u_int16_t _tmp;                                                 \
  92         P_16_COPY(a, &_tmp);                                            \
  93         ((u_int8_t *)a)[0] = ((u_int8_t *)&_tmp)[1];                    \
  94         ((u_int8_t *)a)[1] = ((u_int8_t *)&_tmp)[0];                    \
  95 }
  96
  97 #define SWAP32(p) {                                                     \
  98         P_32_SWAP(p);                                                   \
  99         (p) += sizeof(u_int32_t);                                       \
 100 }
 101 #define SWAP16(p) {                                                     \
 102         P_16_SWAP(p);                                                   \
 103         (p) += sizeof(u_int16_t);                                       \
 104 }
 105 #endif /* !_DB_SWAP_H_ */