move libevent into base

third_party/libevent/min_heap.h

-/*
- * Copyright (c) 2006 Maxim Yegorushkin <maxim.yegorushkin@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.
- * 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 "event.h"
-#include "evutil.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_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);
-
-int min_heap_elem_greater(struct event *a, struct event *b)
-{
-    return evutil_timercmp(&a->ev_timeout, &b->ev_timeout, >);
-}
-
-void min_heap_ctor(min_heap_t* s) { s->p = 0; s->n = 0; s->a = 0; }
-void min_heap_dtor(min_heap_t* s) { if(s->p) free(s->p); }
-void min_heap_elem_init(struct event* e) { e->min_heap_idx = -1; }
-int min_heap_empty(min_heap_t* s) { return 0u == s->n; }
-unsigned min_heap_size(min_heap_t* s) { return s->n; }
-struct event* min_heap_top(min_heap_t* s) { return s->n ? *s->p : 0; }
-
-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;
-}
-
-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->min_heap_idx = -1;
-        return e;
-    }
-    return 0;
-}
-
-int min_heap_erase(min_heap_t* s, struct event* e)
-{
-    if(((unsigned int)-1) != e->min_heap_idx)
-    {
-        struct event *last = s->p[--s->n];
-        unsigned parent = (e->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->min_heap_idx > 0 && min_heap_elem_greater(s->p[parent], last))
-             min_heap_shift_up_(s, e->min_heap_idx, last);
-        else
-             min_heap_shift_down_(s, e->min_heap_idx, last);
-        e->min_heap_idx = -1;
-        return 0;
-    }
-    return -1;
-}
-
-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**)realloc(s->p, a * sizeof *p)))
-            return -1;
-        s->p = p;
-        s->a = a;
-    }
-    return 0;
-}
-
-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])->min_heap_idx = hole_index;
-        hole_index = parent;
-        parent = (hole_index - 1) / 2;
-    }
-    (s->p[hole_index] = e)->min_heap_idx = hole_index;
-}
-
-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])->min_heap_idx = hole_index;
-        hole_index = min_child;
-        min_child = 2 * (hole_index + 1);
-        }
-    min_heap_shift_up_(s, hole_index,  e);
-}
-
-#endif /* _MIN_HEAP_H_ */