Endianess.h

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/*
 * endian.c
 *
 * Copyright (C) 2013 IBR, TU Braunschweig
 *
 * Written-by: Johannes Morgenroth <morgenroth@ibr.cs.tu-bs.de>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

// DO NOT INCLUDE THIS FILE IN A HEADER FILE!

#include <stdint.h>

#ifndef ENDIANESS_H_
#define ENDIANESS_H_

namespace dtn
{
        namespace data
        {
                uint16_t bswap16(uint16_t x);
                uint32_t bswap32(uint32_t x);
                uint64_t bswap64(uint64_t x);
        }
}

#ifdef HAVE_GLIB
        // GLIB provides optimized macros for endianess conversion
        // we prefer to use them
        #include <glib.h>
#else
        // include endianess headers
        #if HAVE_ENDIAN_H
                // include standard POSIX endian.h
                #include <endian.h>
        #elif HAVE_MACHINE_ENDIAN_H
                // include BSD endian.h
                #include <machine/endian.h>
        #elif __WIN32__
                // windows has no endian header, but
                // provides byte swapping in the winsock2 API
                #include <winsock2.h>
                #define BYTE_ORDER __BYTE_ORDER
                #define LITTLE_ENDIAN __LITTLE_ENDIAN
        #endif

        // check if system byte order is network order
        #if BYTE_ORDER == LITTLE_ENDIAN
                // if POSIX htobe16 is available use it
                #ifdef htobe16
                #define GUINT16_TO_BE(x) htobe16(x)
                #else
                #define GUINT16_TO_BE(x) dtn::data::bswap16(x)
                #endif

                // if POSIX htobe32 is available use it
                #ifdef htobe32
                #define GUINT32_TO_BE(x) htobe32(x)
                #else
                #define GUINT32_TO_BE(x) dtn::data::bswap32(x)
                #endif

                // if POSIX htobe64 is available use it
                #ifdef htobe64
                #define GUINT64_TO_BE(x) htobe64(x)
                #else
                #define GUINT64_TO_BE(x) dtn::data::bswap64(x)
                #endif
        #else
                // system byte order is equal to network byte order
                // generate dummy macros
                #define GUINT16_TO_BE(x) (x)
                #define GUINT32_TO_BE(x) (x)
                #define GUINT64_TO_BE(x) (x)
        #endif
#endif

#endif /* ENDIANESS_H_ */