/*
 *  DMS Tools and Utilities
 *  Copyright (C) 2012 David M. Syzdek <david@syzdek.net>.
 *
 *  @SYZDEK_LICENSE_HEADER_START@
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are
 *  met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of David M. Syzdek 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 COPYRIGHT HOLDERS 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 DAVID M. SYZDEK 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.
 *
 *  @SYZDEK_LICENSE_HEADER_END@
 */
/**
 *  @file src/endian.c determines the byte order of the system
 */
/*
 *  Simple Build:
 *     gcc -W -Wall -O2 -c endian.c
 *     gcc -W -Wall -O2 -o endian   endian.o
 *
 *  GNU Libtool Build:
 *     libtool --mode=compile gcc -W -Wall -g -O2 -c endian.c
 *     libtool --mode=link    gcc -W -Wall -g -O2 -o endian endian.lo
 *
 *  GNU Libtool Install:
 *     libtool --mode=install install -c endian /usr/local/bin/endian
 *
 *  GNU Libtool Clean:
 *     libtool --mode=clean rm -f endian.lo endian
 */
#define _DMSTOOLS_SRC_ENDIAN_C 1

///////////////
//           //
//  Headers  //
//           //
///////////////

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>
#include <inttypes.h>
#include <stdlib.h>
#include <getopt.h>
#include <string.h>


///////////////////
//               //
//  Definitions  //
//               //
///////////////////

#ifndef PROGRAM_NAME
#define PROGRAM_NAME "endian"
#endif
#ifndef PACKAGE_BUGREPORT
#define PACKAGE_BUGREPORT "david@syzdek.net"
#endif
#ifndef PACKAGE_COPYRIGHT
#define PACKAGE_COPYRIGHT ""
#endif
#ifndef PACKAGE_NAME
#define PACKAGE_NAME ""
#endif
#ifndef PACKAGE_VERSION
#define PACKAGE_VERSION ""
#endif


//////////////////
//              //
//  Prototypes  //
//              //
//////////////////

// determines byte order
int is_big_endian(void);

// main statement
int main(int argc, char * argv[]);

//displays usage information
void my_usage(void);

// displays version information
void my_version(void);


/////////////////
//             //
//  Functions  //
//             //
/////////////////

/// determines byte order
int is_big_endian(void)
{
   union
   {
      uint32_t i;
      char     c[4];
   } endian = { 0x01020304 };
   return((endian.c[0] == 1));
}


/// main statement
/// @param[in] argc   number of arguments
/// @param[in] argv   array of arguments
int main(int argc, char * argv[])
{
   int       c;
   int       opt_index;

   // getopt options
   static char   short_opt[] = "hV";
   static struct option long_opt[] =
   {
      {"help",          no_argument, 0, 'h'},
      {"version",       no_argument, 0, 'V'},
      {NULL,            0,           0, 0  }
   };

   while((c = getopt_long(argc, argv, short_opt, long_opt, &opt_index)) != -1)
   {
      switch(c)
      {
         case -1:	/* no more arguments */
         case 0:	/* long options toggles */
            break;
         case 'h':
            my_usage();
            return(0);
         case 'V':
            my_version();
            return(0);
         case '?':
            fprintf(stderr, "Try `%s --help' for more information.\n", PROGRAM_NAME);
            return(1);
         default:
            fprintf(stderr, "%s: unrecognized option `--%c'\n", PROGRAM_NAME, c);
            fprintf(stderr, "Try `%s --help' for more information.\n", PROGRAM_NAME);
            return(1);
      };
   };

   // checks for extra arguments
   if (optind != argc)
   {
      fprintf(stderr, "%s: unknown option `%s'\n", PROGRAM_NAME, argv[optind]);
      fprintf(stderr, "Try `%s --help' for more information.\n", PROGRAM_NAME);
      return(1);
   };

   // prints byte order
   if ((is_big_endian()))
      printf("big endian\n");
   else
      printf("little endian\n");

   return(0);
}


/// displays usage information
void my_usage()
{
   printf("Usage: %s\n", PROGRAM_NAME);
   printf("\n");
   printf("Report bugs to <%s>.\n", PACKAGE_BUGREPORT);
   return;
}


/// displays version information
void my_version(void)
{
   printf("%s (%s) %s\n", PROGRAM_NAME, PACKAGE_NAME, PACKAGE_VERSION);
   printf("Written by David M. Syzdek.\n");
   printf("\n");
   printf("%s\n", PACKAGE_COPYRIGHT);
   printf("This is free software; see the source for copying conditions.  There is NO\n");
   printf("warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n");
   return;
}

/* end of source code */