/*----------------------------------------------------------------------
  File    : hashtest.c
  Contents: test of static hash tables
  Author  : Christian Borgelt
  History : 04.06.1998 file created
            02.09.1998 adapted to changes of module hashtab
----------------------------------------------------------------------*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "hashtab.h"

/*----------------------------------------------------------------------
  Preprocessor Definitions
----------------------------------------------------------------------*/
#define NAMELEN   256           /* maximal length of names */
#define TABSIZE   19            /* size of hash table */

/*----------------------------------------------------------------------
  Auxiliary Functions
----------------------------------------------------------------------*/

static char* getname (char *buf, int maxlen)
{                               /* --- read a name */
  char *dst, *src;              /* to traverse the name read */

  fgets(buf, maxlen, stdin);    /* read a string from stdin */
  dst = src = buf;              /* traverse the name read */
  while ((*src == ' ') || (*src == '\t'))
    src++;                      /* skip leading blanks */
  while (*src) *dst++ = *src++; /* copy name to front */
  if ((dst > buf) && (*(dst-1) == '\n'))
    dst--;                      /* if there is a newline, remove it */
  *dst = '\0';                  /* terminate the string */
  return buf;                   /* return buffer read into */
}  /* getname() */

/*--------------------------------------------------------------------*/

static unsigned int hash (const char *s)
{                               /* --- hash function */
  unsigned int h = 0;           /* hash value */

  while (*s) h = (h << 3) ^ (unsigned int)*s++;
  return h;                     /* compute hash value */
}  /* hash() */

/*----------------------------------------------------------------------
  Main Function
----------------------------------------------------------------------*/

int main (int argc, char *argv[])
{                               /* --- main function */
  int     i, cnt;               /* loop variable, number of elements */
  HASHTAB *htab;                /* hash table */
  char    name[NAMELEN];        /* name to insert/look up */
  char    *tmp;                 /* buffer for name to insert */
  int     cmd;                  /* command */

  htab = ht_create(TABSIZE, (HASHFN*)hash, (HT_CMPFN*)strcmp, free);
  if (!htab) { printf("%s: not enough memory\n", argv[0]); return -1; }
                                /* create a hash table */
  printf("%s --- demonstration of static hashing\n", argv[0]);
  printf("type l for a list of commands\n");
  while (1) {                   /* command loop */
    printf("> "); fflush(stdout);
    do { cmd = getchar();       /* get next command */
    } while (strchr(" \t\n", cmd) != NULL);
    switch (cmd) {              /* evaluate command */
      case 'i':                 /* -- insert into hash table */
        tmp = (char*)malloc(strlen(getname(name, NAMELEN)) +1);
        if (!tmp) { printf("not enough memory\n"); break; }
        i = ht_insert(htab, strcpy(tmp, name));
        if (i >= 0) break;      /* insert name into vector */
        if (i < -1) printf("%s already exists\n", name);
        else        printf("not enough memory\n");
        free(tmp); break;       /* if an error occured, delete name */
      case 'o':                 /* -- look up in hash table */
        tmp = ht_lookup(htab, getname(name, NAMELEN));
        printf("%s %sfound\n", name, (tmp) ? "" : "not ");
        break;                  /* look up name and print result */
      case 'c':                 /* -- clear hash table */
        ht_clear(htab); break;
      case 's':                 /* -- show hash table contents */
        for (cnt = ht_size(htab), i = 0; i < cnt; i++) {
          printf("%2li:", i);   /* traverse hash table */
          tmp = ht_get(htab, i);
          if (tmp) printf(" \"%s\"", tmp);
          printf("\n");         /* print all hash table elements */
        } break;       
      case 'l':                 /* -- print help */
        printf("commands:\n");  /* (i.e. a list of commands) */
        printf("i n  --- insert name n into hash table\n");
        printf("o n  --- look up name n in hash table\n");
        printf("c    --- clear hash table (remove all names)\n");
        printf("s    --- show contents of hash table\n");
        printf("l    --- print this list of commands\n");
        printf("q    --- quit program\n");                break;
      case 'q':                 /* -- quit program */
        ht_delete(htab);        /* delete hash table */
        return 0;               /* return `ok' */
      default:                  /* -- unknown command */
        printf("unknown command --- type l for a list\n"); break;
    }
  }  /* while (1) */
}  /* main() */