162 lines
5.9 KiB
C
162 lines
5.9 KiB
C
|
/* $NetBSD: minheap-internal.h,v 1.2 2013/04/12 18:11:15 joerg Exp $ */
|
||
|
/*
|
||
|
* Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
|
||
|
*
|
||
|
* Copyright (c) 2006 Maxim Yegorushkin <maxim.yegorushkin@gmail.com>
|
||
|
*
|
||
|
* 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.
|
||
|
* 3. The name of the author may not be used to endorse or promote products
|
||
|
* derived from this software without specific prior written permission.
|
||
|
*
|
||
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
|
||
|
*/
|
||
|
#ifndef _MIN_HEAP_H_
|
||
|
#define _MIN_HEAP_H_
|
||
|
|
||
|
#include "event2/event-config.h"
|
||
|
#include "event2/event.h"
|
||
|
#include "event2/event_struct.h"
|
||
|
#include "event2/util.h"
|
||
|
#include "util-internal.h"
|
||
|
#include "mm-internal.h"
|
||
|
|
||
|
typedef struct min_heap
|
||
|
{
|
||
|
struct event** p;
|
||
|
unsigned n, a;
|
||
|
} min_heap_t;
|
||
|
|
||
|
static inline void min_heap_ctor(min_heap_t* s);
|
||
|
static inline void min_heap_dtor(min_heap_t* s);
|
||
|
static inline void min_heap_elem_init(struct event* e);
|
||
|
static inline int min_heap_elt_is_top(const struct event *e);
|
||
|
static inline int min_heap_elem_greater(struct event *a, struct event *b);
|
||
|
static inline int min_heap_empty(min_heap_t* s);
|
||
|
static inline unsigned min_heap_size(min_heap_t* s);
|
||
|
static inline struct event* min_heap_top(min_heap_t* s);
|
||
|
static inline int min_heap_reserve(min_heap_t* s, unsigned n);
|
||
|
static inline int min_heap_push(min_heap_t* s, struct event* e);
|
||
|
static inline struct event* min_heap_pop(min_heap_t* s);
|
||
|
static inline int min_heap_erase(min_heap_t* s, struct event* e);
|
||
|
static inline void min_heap_shift_up_(min_heap_t* s, unsigned hole_index, struct event* e);
|
||
|
static inline void min_heap_shift_down_(min_heap_t* s, unsigned hole_index, struct event* e);
|
||
|
|
||
|
static inline int min_heap_elem_greater(struct event *a, struct event *b)
|
||
|
{
|
||
|
return evutil_timercmp(&a->ev_timeout, &b->ev_timeout, >);
|
||
|
}
|
||
|
|
||
|
static inline void min_heap_ctor(min_heap_t* s) { s->p = 0; s->n = 0; s->a = 0; }
|
||
|
static inline void min_heap_dtor(min_heap_t* s) { if (s->p) mm_free(s->p); }
|
||
|
static inline void min_heap_elem_init(struct event* e) { e->ev_timeout_pos.min_heap_idx = -1; }
|
||
|
static inline int min_heap_empty(min_heap_t* s) { return 0u == s->n; }
|
||
|
static inline unsigned min_heap_size(min_heap_t* s) { return s->n; }
|
||
|
static inline struct event* min_heap_top(min_heap_t* s) { return s->n ? *s->p : 0; }
|
||
|
|
||
|
static inline int min_heap_push(min_heap_t* s, struct event* e)
|
||
|
{
|
||
|
if (min_heap_reserve(s, s->n + 1))
|
||
|
return -1;
|
||
|
min_heap_shift_up_(s, s->n++, e);
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
static inline struct event* min_heap_pop(min_heap_t* s)
|
||
|
{
|
||
|
if (s->n)
|
||
|
{
|
||
|
struct event* e = *s->p;
|
||
|
min_heap_shift_down_(s, 0u, s->p[--s->n]);
|
||
|
e->ev_timeout_pos.min_heap_idx = -1;
|
||
|
return e;
|
||
|
}
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
static inline int min_heap_elt_is_top(const struct event *e)
|
||
|
{
|
||
|
return e->ev_timeout_pos.min_heap_idx == 0;
|
||
|
}
|
||
|
|
||
|
static inline int min_heap_erase(min_heap_t* s, struct event* e)
|
||
|
{
|
||
|
if (-1 != e->ev_timeout_pos.min_heap_idx)
|
||
|
{
|
||
|
struct event *last = s->p[--s->n];
|
||
|
unsigned parent = (e->ev_timeout_pos.min_heap_idx - 1) / 2;
|
||
|
/* we replace e with the last element in the heap. We might need to
|
||
|
shift it upward if it is less than its parent, or downward if it is
|
||
|
greater than one or both its children. Since the children are known
|
||
|
to be less than the parent, it can't need to shift both up and
|
||
|
down. */
|
||
|
if (e->ev_timeout_pos.min_heap_idx > 0 && min_heap_elem_greater(s->p[parent], last))
|
||
|
min_heap_shift_up_(s, e->ev_timeout_pos.min_heap_idx, last);
|
||
|
else
|
||
|
min_heap_shift_down_(s, e->ev_timeout_pos.min_heap_idx, last);
|
||
|
e->ev_timeout_pos.min_heap_idx = -1;
|
||
|
return 0;
|
||
|
}
|
||
|
return -1;
|
||
|
}
|
||
|
|
||
|
static inline int min_heap_reserve(min_heap_t* s, unsigned n)
|
||
|
{
|
||
|
if (s->a < n)
|
||
|
{
|
||
|
struct event** p;
|
||
|
unsigned a = s->a ? s->a * 2 : 8;
|
||
|
if (a < n)
|
||
|
a = n;
|
||
|
if (!(p = (struct event**)mm_realloc(s->p, a * sizeof *p)))
|
||
|
return -1;
|
||
|
s->p = p;
|
||
|
s->a = a;
|
||
|
}
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
static inline void min_heap_shift_up_(min_heap_t* s, unsigned hole_index, struct event* e)
|
||
|
{
|
||
|
unsigned parent = (hole_index - 1) / 2;
|
||
|
while (hole_index && min_heap_elem_greater(s->p[parent], e))
|
||
|
{
|
||
|
(s->p[hole_index] = s->p[parent])->ev_timeout_pos.min_heap_idx = hole_index;
|
||
|
hole_index = parent;
|
||
|
parent = (hole_index - 1) / 2;
|
||
|
}
|
||
|
(s->p[hole_index] = e)->ev_timeout_pos.min_heap_idx = hole_index;
|
||
|
}
|
||
|
|
||
|
static inline void min_heap_shift_down_(min_heap_t* s, unsigned hole_index, struct event* e)
|
||
|
{
|
||
|
unsigned min_child = 2 * (hole_index + 1);
|
||
|
while (min_child <= s->n)
|
||
|
{
|
||
|
min_child -= min_child == s->n || min_heap_elem_greater(s->p[min_child], s->p[min_child - 1]);
|
||
|
if (!(min_heap_elem_greater(e, s->p[min_child])))
|
||
|
break;
|
||
|
(s->p[hole_index] = s->p[min_child])->ev_timeout_pos.min_heap_idx = hole_index;
|
||
|
hole_index = min_child;
|
||
|
min_child = 2 * (hole_index + 1);
|
||
|
}
|
||
|
(s->p[hole_index] = e)->ev_timeout_pos.min_heap_idx = hole_index;
|
||
|
}
|
||
|
|
||
|
#endif /* _MIN_HEAP_H_ */
|