/*
 * An implementation of tries.
 */

#ifndef _TRI_H_
#define _TRI_H_

#include <stdbool.h>

#define NUM_ALPHA_CHARS (256)

struct tri_node {
	struct tri_node *nodes[NUM_ALPHA_CHARS];
	void *value;
};

struct tri {
	struct tri_node *head;
};


/**
 *  Initialize a tri and set its maximum depth.
 */
void tri_init(struct tri *tri);

/**
 *  Destroys an initialized tri and frees its internal structures.
 */
void tri_free(struct tri *tri);

/**
 *  Add a string as a key, and a value to the tri.
 */
int tri_add_string(struct tri *tri, const char *string, void * value);

/**
 *  Returns the value cooresponding to string. If the string is not in the tri, return
 *  NULL.
 */
void *tri_get_string(struct tri *tri, const char *string);

/**
 *  Returns the value cooresponding to the longest matching prefix
 */
void *tri_prefix_match(struct tri *tri, const char *string);

/**
 *  Using 'string' as a prefix, returns the value of the cooresponding string if there
 *  is only one that matches.
 *
 *  If there are multiple possible matches, return NULL and set 'ambiguous' to true. If
 *  there are no possible matches, return NULL and set 'ambiguous' to false.
 */
void *tri_get_string_autocomplete(struct tri *tri, const char *string, bool *ambiguous);


#endif