set.h

/*
 * Copyright (C) 1995-2011 University of Karlsruhe.  All right reserved.
 *
 * This file is part of libFirm.
 *
 * This file may be distributed and/or modified under the terms of the
 * GNU General Public License version 2 as published by the Free Software
 * Foundation and appearing in the file LICENSE.GPL included in the
 * packaging of this file.
 *
 * Licensees holding valid libFirm Professional Edition licenses may use
 * this file in accordance with the libFirm Commercial License.
 * Agreement provided with the Software.
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE.
 */

/**
 * @file
 * @brief       hashset: datastructure containing objects accessible by their key
 * @author      Markus Armbruster
 * @version     $Id$
 */
#ifndef FIRM_ADT_SET_H
#define FIRM_ADT_SET_H

#include <stddef.h>

#include "../begin.h"

/**
 * The abstract type of a set.
 *
 * This sets stores copies of its elements, so there is no need
 * to store the elements after they were added to a set.
 *
 * @see pset
 */
typedef struct set set;

/** The entry of a set, representing an element in the set and its meta-information */
typedef struct set_entry {
	unsigned hash;  /**< the hash value of the element */
	size_t size;    /**< the size of the element */
	int dptr[1];    /**< the element itself, data copied in must not need more
	                     alignment than this */
} set_entry;

/**
 * The type of a set compare function.
 *
 * @param elt   pointer to an element
 * @param key   pointer to another element
 * @param size  size of the elements
 *
 * @return
 *    0 if the elements are identically, non-zero else
 *
 * @note
 *    Although it is possible to define different meanings of equality
 *    of two elements of a set, they can be only equal if their sizes are
 *    are equal. This is checked before the compare function is called.
 */
typedef int (*set_cmp_fun) (const void *elt, const void *key, size_t size);

/**
 * Creates a new set.
 *
 * @param func    The compare function of this set.
 * @param slots   Initial number of collision chains.  I.e., \#slots
 *                different keys can be hashed without collisions.
 *
 * @returns
 *    created set
 */
FIRM_API set *new_set(set_cmp_fun func, size_t slots);

/**
 * Deletes a set and all elements of it.
 *
 * @param set  the set to delete
 */
FIRM_API void del_set(set *set);

/**
 * Returns the number of elements in a set.
 *
 * @param set   the set
 */
FIRM_API size_t set_count(set *set);

/**
 * Searches an element in a set.
 *
 * @param set   the set to search in
 * @param key   the element to is searched
 * @param size  the size of key
 * @param hash  the hash value of key
 *
 * @return
 *    The address of the found element in the set or NULL if it was not found.
 */
FIRM_API void *set_find(set *set, const void *key, size_t size, unsigned hash);

/**
 * Inserts an element into a set.
 *
 * @param set   the set to insert in
 * @param key   a pointer to the element to be inserted.  Element is copied!
 * @param size  the size of the element that should be inserted
 * @param hash  the hash-value of the element
 *
 * @return a pointer to the inserted element
 *
 * @note
 *    It is not possible to insert one element more than once. If an element
 *    that should be inserted is already in the set, this functions does
 *    nothing but returning its pointer.
 */
FIRM_API void *set_insert(set *set, const void *key, size_t size, unsigned hash);

/**
 * Inserts an element into a set and returns its set_entry.
 *
 * @param set   the set to insert in
 * @param key   a pointer to the element to be inserted. Element is copied!
 * @param size  the size of the element that should be inserted
 * @param hash  the hash-value of the element
 *
 * @return a pointer to the set_entry of the inserted element
 *
 * @note
 *    It is not possible to insert an element more than once. If an element
 *    that should be inserted is already in the set, this functions does
 *    nothing but returning its set_entry.
 */
FIRM_API set_entry *set_hinsert(set *set, const void *key, size_t size, unsigned hash);

/**
 * Inserts an element into a set, zero-terminate it and returns its set_entry.
 *
 * @param set   the set to insert in
 * @param key   a pointer to the element to be inserted.  Element is copied!
 * @param size  the size of the element that should be inserted
 * @param hash  the hash-value of the element
 *
 * @return a pointer to the set_entry of the inserted element
 *
 * @note
 *    It is not possible to insert on element more than once. If an element
 *    that should be inserted is already in the set, this functions does
 *    nothing but returning its set_entry.
 */
FIRM_API set_entry *set_hinsert0(set *set, const void *key, size_t size, unsigned hash);

/**
 * Returns the first element of a set.
 *
 * @param set  the set to iterate
 *
 * @return a pointer to the element or NULL if the set is empty
 */
FIRM_API void *set_first(set *set);

/**
 * Returns the next element of a set.
 *
 * @param set  the set to iterate
 *
 * @return a pointer to the next element or NULL if the
 *         iteration is finished
 */
FIRM_API void *set_next(set *set);

/**
 * Breaks the iteration of a set. Must be called before
 * the next set_first() call if the iteration was NOT
 * finished.
 *
 * @param set  the set
 */
FIRM_API void set_break(set *set);

/**
 * Iterates over an set.
 *
 * @param set    the set
 * @param entry  the iterator
 */
#define foreach_set(set, type, entry) for (entry = (type) set_first(set); entry; entry = (type) set_next(set))

/* implementation specific */
#define new_set(cmp, slots) ((new_set) ((cmp), (slots)))
#define set_find(set, key, size, hash) \
  _set_search ((set), (key), (size), (hash), _set_find)
#define set_insert(set, key, size, hash) \
  _set_search ((set), (key), (size), (hash), _set_insert)
#define set_hinsert(set, key, size, hash) \
  ((set_entry *)_set_search ((set), (key), (size), (hash), _set_hinsert))
#define set_hinsert0(set, key, size, hash) \
  ((set_entry *)_set_search ((set), (key), (size), (hash), _set_hinsert0))

#define SET_VRFY(set) (void)0

#ifdef STATS
/**
 * Prints statistics on a set to stdout.
 *
 * @param set  the set
 */
void set_stats (set *set);
#else
# define set_stats(s) ((void)0)
#endif

#ifdef DEBUG
/**
 * Describe a set.
 *
 * Writes a description of a set to stdout. The description includes:
 * - a header telling how many elements (nkey) and segments (nseg) are in use
 * - for every collision chain the number of element with its hash values
 *
 * @param set  the set
 */
FIRM_API void set_describe(set *set);
#endif


/* Private */

typedef enum { _set_find, _set_insert, _set_hinsert, _set_hinsert0 } _set_action;

FIRM_API void *_set_search(set *, const void *, size_t, unsigned, _set_action);

#include "../end.h"

#endif