db_swap.h

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996-2005
 *      Sleepycat Software.  All rights reserved.
 */
/*
 * Copyright (c) 1990, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $Id: db_swap.h,v 12.3 2005/06/16 20:21:47 bostic Exp $
 */

#ifndef _DB_SWAP_H_
#define _DB_SWAP_H_

/*
 * Little endian <==> big endian 64-bit swap macros.
 *      M_64_SWAP       swap a memory location
 *      P_64_COPY       copy potentially unaligned 4 byte quantities
 *      P_64_SWAP       swap a referenced memory location
 */
#undef  M_64_SWAP
#define M_64_SWAP(a) {                                                  \
        u_int64_t _tmp;                                                 \
        _tmp = (u_int64_t)a;                                            \
        ((u_int8_t *)&a)[0] = ((u_int8_t *)&_tmp)[7];                   \
        ((u_int8_t *)&a)[1] = ((u_int8_t *)&_tmp)[6];                   \
        ((u_int8_t *)&a)[2] = ((u_int8_t *)&_tmp)[5];                   \
        ((u_int8_t *)&a)[3] = ((u_int8_t *)&_tmp)[4];                   \
        ((u_int8_t *)&a)[4] = ((u_int8_t *)&_tmp)[3];                   \
        ((u_int8_t *)&a)[5] = ((u_int8_t *)&_tmp)[2];                   \
        ((u_int8_t *)&a)[6] = ((u_int8_t *)&_tmp)[1];                   \
        ((u_int8_t *)&a)[7] = ((u_int8_t *)&_tmp)[0];                   \
}
#undef  P_64_COPY
#define P_64_COPY(a, b) {                                               \
        ((u_int8_t *)b)[0] = ((u_int8_t *)a)[0];                        \
        ((u_int8_t *)b)[1] = ((u_int8_t *)a)[1];                        \
        ((u_int8_t *)b)[2] = ((u_int8_t *)a)[2];                        \
        ((u_int8_t *)b)[3] = ((u_int8_t *)a)[3];                        \
        ((u_int8_t *)b)[4] = ((u_int8_t *)a)[4];                        \
        ((u_int8_t *)b)[5] = ((u_int8_t *)a)[5];                        \
        ((u_int8_t *)b)[6] = ((u_int8_t *)a)[6];                        \
        ((u_int8_t *)b)[7] = ((u_int8_t *)a)[7];                        \
}
#undef  P_64_SWAP
#define P_64_SWAP(a) {                                                  \
        u_int64_t _tmp;                                                 \
        P_64_COPY(a, &_tmp);                                            \
        ((u_int8_t *)a)[0] = ((u_int8_t *)&_tmp)[7];                    \
        ((u_int8_t *)a)[1] = ((u_int8_t *)&_tmp)[6];                    \
        ((u_int8_t *)a)[2] = ((u_int8_t *)&_tmp)[5];                    \
        ((u_int8_t *)a)[3] = ((u_int8_t *)&_tmp)[4];                    \
        ((u_int8_t *)a)[4] = ((u_int8_t *)&_tmp)[3];                    \
        ((u_int8_t *)a)[5] = ((u_int8_t *)&_tmp)[2];                    \
        ((u_int8_t *)a)[6] = ((u_int8_t *)&_tmp)[1];                    \
        ((u_int8_t *)a)[7] = ((u_int8_t *)&_tmp)[0];                    \
}

/*
 * Little endian <==> big endian 32-bit swap macros.
 *      M_32_SWAP       swap a memory location
 *      P_32_COPY       copy potentially unaligned 4 byte quantities
 *      P_32_SWAP       swap a referenced memory location
 */
#undef  M_32_SWAP
#define M_32_SWAP(a) {                                                  \
        u_int32_t _tmp;                                                 \
        _tmp = (u_int32_t)a;                                            \
        ((u_int8_t *)&a)[0] = ((u_int8_t *)&_tmp)[3];                   \
        ((u_int8_t *)&a)[1] = ((u_int8_t *)&_tmp)[2];                   \
        ((u_int8_t *)&a)[2] = ((u_int8_t *)&_tmp)[1];                   \
        ((u_int8_t *)&a)[3] = ((u_int8_t *)&_tmp)[0];                   \
}
#undef  P_32_COPY
#define P_32_COPY(a, b) {                                               \
        ((u_int8_t *)b)[0] = ((u_int8_t *)a)[0];                        \
        ((u_int8_t *)b)[1] = ((u_int8_t *)a)[1];                        \
        ((u_int8_t *)b)[2] = ((u_int8_t *)a)[2];                        \
        ((u_int8_t *)b)[3] = ((u_int8_t *)a)[3];                        \
}
#undef  P_32_SWAP
#define P_32_SWAP(a) {                                                  \
        u_int32_t _tmp;                                                 \
        P_32_COPY(a, &_tmp);                                            \
        ((u_int8_t *)a)[0] = ((u_int8_t *)&_tmp)[3];                    \
        ((u_int8_t *)a)[1] = ((u_int8_t *)&_tmp)[2];                    \
        ((u_int8_t *)a)[2] = ((u_int8_t *)&_tmp)[1];                    \
        ((u_int8_t *)a)[3] = ((u_int8_t *)&_tmp)[0];                    \
}

/*
 * Little endian <==> big endian 16-bit swap macros.
 *      M_16_SWAP       swap a memory location
 *      P_16_COPY       copy potentially unaligned 2 byte quantities
 *      P_16_SWAP       swap a referenced memory location
 */
#undef  M_16_SWAP
#define M_16_SWAP(a) {                                                  \
        u_int16_t _tmp;                                                 \
        _tmp = (u_int16_t)a;                                            \
        ((u_int8_t *)&a)[0] = ((u_int8_t *)&_tmp)[1];                   \
        ((u_int8_t *)&a)[1] = ((u_int8_t *)&_tmp)[0];                   \
}
#undef  P_16_COPY
#define P_16_COPY(a, b) {                                               \
        ((u_int8_t *)b)[0] = ((u_int8_t *)a)[0];                        \
        ((u_int8_t *)b)[1] = ((u_int8_t *)a)[1];                        \
}
#undef  P_16_SWAP
#define P_16_SWAP(a) {                                                  \
        u_int16_t _tmp;                                                 \
        P_16_COPY(a, &_tmp);                                            \
        ((u_int8_t *)a)[0] = ((u_int8_t *)&_tmp)[1];                    \
        ((u_int8_t *)a)[1] = ((u_int8_t *)&_tmp)[0];                    \
}

#undef  SWAP32
#define SWAP32(p) {                                                     \
        P_32_SWAP(p);                                                   \
        (p) += sizeof(u_int32_t);                                       \
}
#undef  SWAP16
#define SWAP16(p) {                                                     \
        P_16_SWAP(p);                                                   \
        (p) += sizeof(u_int16_t);                                       \
}

/*
 * Berkeley DB has local versions of htonl() and ntohl() that operate on
 * pointers to the right size memory locations; the portability magic for
 * finding the real system functions isn't worth the effort.
 */
#undef  DB_HTONL
#define DB_HTONL(p) do {                                                \
        if (!__db_isbigendian())                                        \
                P_32_SWAP(p);                                           \
} while (0)
#undef  DB_NTOHL
#define DB_NTOHL(p) do {                                                \
        if (!__db_isbigendian())                                        \
                P_32_SWAP(p);                                           \
} while (0)

#endif /* !_DB_SWAP_H_ */

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