/* modified by Juncheng Yang for use in libCacheSim 201606
 */

/*
 * Copyright (c) 2014, Volkan Yazıcı <volkan.yazici@gmail.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * @file  pqueue.h
 * @brief Priority Queue function declarations
 *
 * @{
 */

#ifndef PQUEUE_H
#define PQUEUE_H

#ifdef __cplusplus
extern "C" {
#endif

#include <stdio.h>

#include "../include/config.h"

/** priority data type */
struct pqueue_pri {
  double pri;
};
typedef struct pqueue_pri pqueue_pri_t;

/** callback functions to get/set/compare the priority of an element */
typedef pqueue_pri_t (*pqueue_get_pri_f)(void *a);
typedef void (*pqueue_set_pri_f)(void *a, pqueue_pri_t pri);
typedef int (*pqueue_cmp_pri_f)(pqueue_pri_t next, pqueue_pri_t curr);

/** callback functions to get/set the position of an element */
typedef size_t (*pqueue_get_pos_f)(void *a);
typedef void (*pqueue_set_pos_f)(void *a, size_t pos);

/** debug callback function to print a entry */
typedef void (*pqueue_print_entry_f)(FILE *out, void *a);

/** the priority queue handle */
typedef struct pqueue_t {
  size_t size;             /**< number of elements in this queue */
  size_t avail;            /**< slots available in this queue */
  size_t step;             /**< growth stepping setting */
  pqueue_cmp_pri_f cmppri; /**< callback to compare nodes */
  pqueue_get_pri_f getpri; /**< callback to get priority of a node */
  pqueue_set_pri_f setpri; /**< callback to set priority of a node */
  pqueue_get_pos_f getpos; /**< callback to get position of a node */
  pqueue_set_pos_f setpos; /**< callback to set position of a node */
  void **d;                /**< The actual queue in binary heap form */
} pqueue_t;

typedef struct node_t {
  pqueue_pri_t pri;
  obj_id_t obj_id;
  size_t pos;
} pq_node_t;

pqueue_t *pqueue_init(size_t n);

/**
 * initialize the queue
 *
 * @param n the initial estimate of the number of queue items for which memory
 *     should be preallocated
 * @param cmppri The callback function to run to compare two elements
 *     This callback should return 0 for 'lower' and non-zero
 *     for 'higher', or vice versa if reverse priority is desired
 * @param setpri the callback function to run to assign a score to an element
 * @param getpri the callback function to run to set a score to an element
 * @param getpos the callback function to get the current element's position
 * @param setpos the callback function to set the current element's position
 *
 * @return the handle or NULL for insufficient memory
 */
pqueue_t *pqueue_init_full(size_t n, pqueue_cmp_pri_f cmppri,
                           pqueue_get_pri_f getpri, pqueue_set_pri_f setpri,
                           pqueue_get_pos_f getpos, pqueue_set_pos_f setpos);

/**
 * free all memory used by the queue
 * @param q the queue
 */
void pqueue_free(pqueue_t *q);

/**
 * return the size of the queue.
 * @param q the queue
 */
size_t pqueue_size(pqueue_t *q);

/**
 * insert an item into the queue.
 * @param q the queue
 * @param d the item
 * @return 0 on success
 */
int pqueue_insert(pqueue_t *q, void *d);

/**
 * move an existing entry to a different priority
 * @param q the queue
 * @param new_pri the new priority
 * @param d the entry
 */
void pqueue_change_priority(pqueue_t *q, pqueue_pri_t new_pri, void *d);

/**
 * pop the highest-ranking item from the queue.
 * @param q the queue
 * @return NULL on error, otherwise the entry
 */
void *pqueue_pop(pqueue_t *q);

/**
 * remove an item from the queue.
 * @param q the queue
 * @param d the entry
 * @return 0 on success
 */
int pqueue_remove(pqueue_t *q, void *d);

/**
 * access highest-ranking item without removing it.
 * @param q the queue
 * @return NULL on error, otherwise the entry
 */
void *pqueue_peek(pqueue_t *q);

/**
 * print the queue
 * @internal
 * DEBUG function only
 * @param q the queue
 * @param out the output handle
 * @param print the callback function to print the entry
 */
void pqueue_print(pqueue_t *q, FILE *out, pqueue_print_entry_f print);

/**
 * dump the queue and it's internal structure
 * @internal
 * debug function only
 * @param q the queue
 * @param out the output handle
 * @param print callback function to print the entry
 */
void pqueue_dump(pqueue_t *q, FILE *out, pqueue_print_entry_f print);

/**
 * checks that the pq is in the right order, etc
 * @internal
 * debug function only
 * @param q the queue
 */
int pqueue_is_valid(pqueue_t *q);

/******************* priority queue structs and def **********************/

static inline int cmp_pri(pqueue_pri_t next, pqueue_pri_t curr) {
  return (next.pri < curr.pri);
}

static inline pqueue_pri_t get_pri(void *a) { return ((pq_node_t *)a)->pri; }

static inline void set_pri(void *a, pqueue_pri_t pri) {
  ((pq_node_t *)a)->pri = pri;
}

static inline size_t get_pos(void *a) { return ((pq_node_t *)a)->pos; }

static inline void set_pos(void *a, size_t pos) { ((pq_node_t *)a)->pos = pos; }

#ifdef __cplusplus
}
#endif

#endif /* PQUEUE_H */
/** @} */
