src/util/heap.h

/* -*- c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* ====================================================================
 * Copyright (c) 1999-2004 Carnegie Mellon University.  All rights
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 * This work was supported in part by funding from the Defense Advanced 
 * Research Projects Agency and the National Science Foundation of the 
 * United States of America, and the CMU Sphinx Speech Consortium.
 *
 * THIS SOFTWARE IS PROVIDED BY CARNEGIE MELLON UNIVERSITY ``AS IS'' AND 
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/*
 * heap.h -- Generic heap structure for inserting in any and popping in sorted
 * 		order.
 *
 * **********************************************
 * CMU ARPA Speech Project
 *
 * Copyright (c) 1999 Carnegie Mellon University.
 * ALL RIGHTS RESERVED.
 * **********************************************
 * 
 * HISTORY
 * $Log: heap.h,v $
 * Revision 1.7  2005/06/22 03:05:49  arthchan2003
 * 1, Fixed doxygen documentation, 2, Add  keyword.
 *
 * Revision 1.4  2005/06/15 04:21:46  archan
 * 1, Fixed doxygen-documentation, 2, Add  keyword such that changes will be logged into a file.
 *
 * Revision 1.3  2005/03/30 01:22:48  archan
 * Fixed mistakes in last updates. Add
 *
 * 
 * 23-Dec-96	M K Ravishankar (rkm@cs.cmu.edu) at Carnegie Mellon University
 * 		Started.
 */


#ifndef _LIBUTIL_HEAP_H_
#define _LIBUTIL_HEAP_H_

#include <stdlib.h>

#include <pocketsphinx/prim_type.h>

  /** \file heap.h
   * \brief Heap Implementation. 
   *
   * General Comment: Sorted heap structure with three main operations:
   * 
   *   1. Insert a data item (with two attributes: an application supplied pointer and an
   *      integer value; the heap is maintained in ascending order of the integer value).
   *   2. Return the currently topmost item (i.e., item with smallest associated value).
   *   3. Return the currently topmost item and pop it off the heap.
   */

#ifdef __cplusplus
extern "C" {
#endif
#if 0
/* Fool Emacs. */
}
#endif


typedef struct heap_s heap_t;


/**
 * Allocate a new heap and return handle to it.
 */
heap_t *heap_new(void);


/**
 * Insert a new item into the given heap.
 * Return value: 0 if successful, -1 otherwise.
 */
int heap_insert(heap_t *heap,	/**< In: Heap into which item is to be inserted */
                void *data,	/**< In: Application-determined data pointer */
                int32 val	/**< In: According to item entered in sorted heap */
	);
/**
 * Return the topmost item in the heap.
 * Return value: 1 if heap is not empty and the topmost value is returned;
 * 0 if heap is empty; -1 if some error occurred.
 */
int heap_top(heap_t *heap,	/**< In: Heap whose topmost item is to be returned */
             void **data,	/**< Out: Data pointer associated with the topmost item */
             int32 *val		/**< Out: Value associated with the topmost item */
	);
/**
 * Like heap_top but also pop the top item off the heap.
 */
int heap_pop(heap_t *heap, void **data, int32 *val);

/**
 * Remove an item from the heap.
 */
int heap_remove(heap_t *heap, void *data);

/**
 * Return the number of items in the heap.
 */
size_t heap_size(heap_t *heap);

/**
 * Destroy the given heap; free the heap nodes.  NOTE: Data pointers in the nodes are NOT freed.
 * Return value: 0 if successful, -1 otherwise.
 */

int heap_destroy(heap_t *heap);

#ifdef __cplusplus
}
#endif

#endif