/*
 * $Header: /home/gene/library/website/docsrc/salt/RCS/salt.c,v 395.1 2008/04/20 17:25:50 gene Exp $
 *
 * Copyright (C) 2004 Gene Michael Stover.
 *
 * This file is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * As a special exception to the GNU General Public License, if you
 * distribute this file as part of a program that contains a
 * configuration script generated by Autoconf, you may include it under
 * the same distribution terms that you use for the rest of that program.
 */

/* Catholic C */
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

/* unix */
#include <unistd.h>
extern int getopt ();
extern char *optarg;
extern int optidx;

static int S_count = 100;
static int S_quantity = 100;
static int S_pinch = 10;

static int
S_Init ()
{
  int rc = 0;

  srand (time (NULL));
  return rc;
}

static int
S_CommandLine (argc, argv)
     int argc;
     char *argv[];
{
  int rc = 0;
  int c;

  while (rc == 0 && (c = getopt (argc, argv, "c:q:p:")) != -1) {
    switch (c) {
    case 'c':
      S_count = atoi (optarg);
      break;
    case 'p':
      S_pinch = atoi (optarg);
      break;
    case 'q':
      S_quantity = atoi (optarg);
      break;
    default:
      fprintf (stderr, "\n%s:%d: unexpected command line opt '%c'",
	       __FILE__, __LINE__, c);
      rc = 42;
    }
  }
  return rc;
}

/*
 * Return the number of items of TYPE in the container.
 */
static int
S_Count (container, type, len)
     char container[];
     char type;
     int len;
{
  int count = 0, i;

  for (i = 0; i < len; ++i) {
    if (container[i] == type) {
      ++count;
    }
  }
  return count;
}

/*
 * Fill the container with one kind of item
 */
static void
S_FillContainer (container, type, len)
     char container[];
     char type;
     int len;
{
  memset (container, type, len);
}

static void
S_SwapChar (x, y)
     char *x;
     char *y;
{
  char tmp;

  tmp = *x;
  *x = *y;
  *y = tmp;
}

static void
S_Shuffle (container, len)
     char container[];
     int len;
{
  int i, j;

  for (i = 0; i < len; ++i) {
    j = rand () % (len - i);
    j += i;
    S_SwapChar (&container[i], &container[j]);
  }
  fprintf (stderr, "\n%s:%d: shuffle debug: ", __FILE__, __LINE__);
  for (i = 0; i < len; ++i) {
    fprintf (stderr, "%c", container[i]);
  }
}

static void
S_Trial (salt, pepper)
     char salt[];
     char pepper[];
{
  /* Fill the pepper container with pepper. */
  S_FillContainer (pepper, 'p', S_quantity);
  /* Append some salt to the pepper. */
  S_FillContainer (&pepper[S_quantity], 's', S_pinch);
  /* Shake the pepper container */
  S_Shuffle (pepper, S_quantity + S_pinch);

  /* Fill the salt -- but it lacks one pinch */
  S_FillContainer (salt, 's', S_quantity - S_pinch);
  /* Append to the salt a pinch from the pepper container. */
  bcopy (&pepper[S_quantity], &salt[S_quantity - S_pinch], S_pinch);
}

static double
S_Rate (container, type, len)
     char container[];
     char type;
     int len;
{
  return S_Count (container, type, len) / (double) len;
}

static void
S_Print (i, salt, pepper, len)
     int i;
     char salt[];
     char pepper[];
     int len;
{
  printf ("\n(salt %d, %d, %.3f), (pepper %d, %d, %.3f)",
	  S_Count (salt, 's', len),   S_Count (salt, 'p', len),
	  S_Rate (salt, 's', len),
	  S_Count (pepper, 's', len), S_Count (pepper, 'p', len),
	  S_Rate (pepper, 'p', len));
  if (S_Rate (salt, 's') != S_Rate (pepper, 'p')) {
    printf (" *");
  }
}

static char *
S_NewContainer ()
{
  return (char *) malloc ((S_quantity + S_pinch) * sizeof *salt);
}

static int
S_Run ()
{
  int rc = 0;
  int i;
  char *salt, *pepper;

  salt = S_NewContainer ();
  pepper = S_NewContainer ();
  for (i = 0; i < S_count; ++i) {
    S_Trial (salt, pepper);
    S_Print (i, salt, pepper, S_quantity);
  }
  free (pepper);
  free (salt);
  return rc;
}

int
main (argc, argv)
     int argc;
     char *argv[];
{
  int rc = 0;

  if (S_Init () == 0) {
    if (S_CommandLine (argc, argv) == 0) {
      if (S_Run () == 0) {
	/* success */
      } else {
	fprintf (stderr, "\n%s:%d: run failed", __FILE__, __LINE__);
	rc = 1010;
      }
    } else {
      fprintf (stderr, "\n%s:%d: command line error", __FILE__, __LINE__);
      rc = 3;
    }
  } else {
    fprintf (stderr, "\n%s:%d: init failed", __FILE__, __LINE__);
    rc = -234;
  }
  printf ("\n");
  return rc == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
}

/* --- end of file --- */