kc3-lang/libevent/min_heap.h

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• Hash : 4e1ec3e0
  Author :
  Date : 2007-11-07T21:01:26
  

  Make all the C files in the libraries compile under MSVC 2005 Express.  There are still a few warnings, and probably some subtle issues, but it's better than nothing.
  
  svn:r499
  

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• 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"
  
  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 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) { 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;
          e->min_heap_idx = -1;
          min_heap_shift_down_(s, 0u, s->p[--s->n]);
          return e;
      }
      return 0;
  }
  
  int min_heap_erase(min_heap_t* s, struct event* e)
  {
      if(((unsigned int)-1) != e->min_heap_idx)
      {
          min_heap_shift_down_(s, e->min_heap_idx, s->p[--s->n]);
          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_ */
  

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