Generic trie implemetnation in C

This a simple implementation of trie data structure in C99. This implementation allows to store sequences of int-s, however one can easy trigger a type of symb in struct trie.

The library includes a simple test-case in the trie.c. In order to make it work, run make test.

Usage

Currently an implemetation provides interfaces to store char based strings in the trie, attaching to each word some information of ssize_t type. For example, consider the following case:

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>

#include "trie.h"

/* some values, we want to attach to every
   word in the trie data base.  */
enum type_of_word {
  type_a, type_b
};

int main (int argc, char *argv[])
{
  int ret = EXIT_SUCCESS;
  ssize_t res;

  /* Initialize new trie.  */
  truct trie *  dict = trie_new ();
  if (argc <= 1)
    {
      (void) fprintf (stderr, "usage: %s word to find\n", argv[0]);
      ret = EXIT_FAILURE;
      goto out;
    }

  /* Add two words of two different types.  */
  trie_add_word (dict, "hello", strlen ("hello"), (ssize_t)type_a);
  trie_add_word (dict, "hell", strlen ("hell"), (ssize_t)type_b);


  printf ("Printing the trie.\n");
  trie_print (dict);

  /* Search the argument in the trie and detect a type of it.  */
  res = trie_search (dict, argv[1], strlen (argv[1]));
  printf ("searching '%s' in the database -- %s\n",
    argv[1],  res != TRIE_NOT_LAST
    ? (enum type_of_word)res == type_a ? "yes, type A" : "yes, type B"
    : "no");

out:
 trie_free (dict);
 return ret;
}

As the type of information you attach is a transparent size_t we need to dedicate one symbol, whic would denote that a certain symbol is not last. Macro TRIE_NOT_LAST serves this purpose.

Tha implementation is valgrinded, and is compiled at strictes gcc warning level.

Send your suggestions or patches.