/**

 *     $Id: hex2chars.c,v 1.1.1.1 2008-04-28 17:32:53 mbroeker Exp $

 * $Source: /development/c/demos/hex2chars.c,v $

 *

 */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <math.h>

#ifndef RUNS

#define RUNS 16

#endif

/*

 * =708== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 13 from 1)

 * ==708== malloc/free: in use at exit: 352 bytes in 32 blocks.

 * ==708== malloc/free: 48 allocs, 16 frees, 3,680 bytes allocated.

 * ==708== For counts of detected errors, rerun with: -v

 * ==708== searching for pointers to 32 not-freed blocks.

 * ==708== checked 68,684 bytes.

 */

const char *characters = "xuzicjklmneopbdaqfrstvgwhy";

char *remap_works (char *str, int slen)

{

    int i;

    int pos;

    static char *s;

    if ((s = malloc (slen + 1)) == NULL)

        return NULL;

    for (i = 0; i < slen; i++) {

        if (str[i] >= 'a') {

            pos = str[i] - 'a';

            s[i] = characters[pos];

        } else {

            /*

             * Let numbers asis

             */

            s[i] = str[i];

        }

    }

    s[i] = 0;

    return s;

}

char *remap_works_not (char *str, int slen)

{

    int i, j;

    double value;

    double *table;

    static char *s;

    int clen = strlen (characters);

    if ((s = malloc (slen + 1)) == NULL)

        return NULL;

    if ((table = calloc (clen, sizeof (double))) == NULL)

        return NULL;

    for (i = 0; i < clen; i++)

        table[i] = cos ('a' + i);

    for (i = 0; i < slen; i++) {

        if (str[i] >= 'a') {

            value = cos (str[i]);

            for (j = 0; j < clen; j++) {

                /*

                 * flip and expand characters

                 */

                s[i] = '*';

                if (value == table[j]) {

                    s[i] = characters[j];

                    break;

                }

                if ((fabs (value - table[j])) < 0.001) {

                    s[i] = characters[j];

                    break;

                }

            }

        } else {

            /*

             * Let numbers asis

             */

            s[i] = str[i];

        }

    }

    s[i] = 0;

    if (table != NULL)

        free (table);

    return s;

}

int main (int argc, char **argv)

{

    int i;

    int len;

    char *start;

    char *end;

    if (argc != 2) {

        printf ("Usage: %s <string>\n", argv[0]);

        exit (0);

    }

    start = argv[1];

    len = strlen (start);

    printf ("\n  --- REMAP_WORKS FINE ---\n\n");

    for (i = 0; i < RUNS; i++) {

        if ((end = remap_works (start, len)) != NULL)

            printf ("%s\t<==>\t%s\n", start, end);

        start = end;

    }

    /*

     * reset state

     */

    start = argv[1];

    printf ("\n  --- REMAP_WORKS_NOT because floating-point comparison is evil at all ---\n\n");

    for (i = 0; i < RUNS; i++) {

        if ((end = remap_works_not (start, len)) != NULL)

            printf ("%s\t<==>\t%s\n", start, end);

        start = end;

    }

    return 0;

}