trunk/src/queue.c

/***************************************
 Queue data type functions.

 Part of the Routino routing software.
 ******************/ /******************
 This file Copyright 2008-2013 Andrew M. Bishop

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU Affero General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU Affero General Public License for more details.

 You should have received a copy of the GNU Affero General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ***************************************/


#include <string.h>
#include <stdlib.h>

#include "results.h"


/*+ A queue of results. +*/
struct _Queue
{
 int      nincrement;           /*+ The amount to increment the queue when full. +*/
 int      nallocated;           /*+ The number of entries allocated. +*/
 int      noccupied;            /*+ The number of entries occupied. +*/

 Result **results;              /*+ The queue of pointers to results. +*/
};


/*++++++++++++++++++++++++++++++++++++++
  Allocate a new queue.

  Queue *NewQueueList Returns the queue.

  uint8_t log2bins The base 2 logarithm of the initial number of bins in the queue.
  ++++++++++++++++++++++++++++++++++++++*/

Queue *NewQueueList(uint8_t log2bins)
{
 Queue *queue;

 queue=(Queue*)malloc(sizeof(Queue));

 queue->nincrement=1<<log2bins;

 queue->nallocated=queue->nincrement;
 queue->noccupied=0;

 queue->results=(Result**)malloc(queue->nallocated*sizeof(Result*));

 return(queue);
}


/*++++++++++++++++++++++++++++++++++++++
  Free a queue.

  Queue *queue The queue to be freed.
  ++++++++++++++++++++++++++++++++++++++*/

void FreeQueueList(Queue *queue)
{
 free(queue->results);

 free(queue);
}


/*++++++++++++++++++++++++++++++++++++++
  Insert a new item into the queue in the right place.

  The data is stored in a "Binary Heap" http://en.wikipedia.org/wiki/Binary_heap
  and this operation is adding an item to the heap.

  Queue *queue The queue to insert the result into.

  Result *result The result to insert into the queue.

  score_t score The score to use for sorting the node.
  ++++++++++++++++++++++++++++++++++++++*/

void InsertInQueue(Queue *queue,Result *result,score_t score)
{
 int index;

 if(result->queued==NOT_QUEUED)
   {
    queue->noccupied++;
    index=queue->noccupied;

    if(queue->noccupied==queue->nallocated)
      {
       queue->nallocated=queue->nallocated+queue->nincrement;
       queue->results=(Result**)realloc((void*)queue->results,queue->nallocated*sizeof(Result*));
      }

    queue->results[index]=result;
    queue->results[index]->queued=index;
   }
 else
    index=result->queued;

 queue->results[index]->sortby=score;

 /* Bubble up the new value */

 while(index>1 &&
       queue->results[index]->sortby<queue->results[index/2]->sortby)
   {
    int newindex;
    Result *temp;

    newindex=index/2;

    temp=queue->results[index];
    queue->results[index]=queue->results[newindex];
    queue->results[newindex]=temp;

    queue->results[index]->queued=index;
    queue->results[newindex]->queued=newindex;

    index=newindex;
   }
}


/*++++++++++++++++++++++++++++++++++++++
  Pop an item from the front of the queue.

  The data is stored in a "Binary Heap" http://en.wikipedia.org/wiki/Binary_heap
  and this operation is deleting the root item from the heap.

  Result *PopFromQueue Returns the top item.

  Queue *queue The queue to remove the result from.
  ++++++++++++++++++++++++++++++++++++++*/

Result *PopFromQueue(Queue *queue)
{
 int index;
 Result *retval;

 if(queue->noccupied==0)
    return(NULL);

 retval=queue->results[1];
 retval->queued=NOT_QUEUED;

 index=1;

 queue->results[index]=queue->results[queue->noccupied];

 queue->noccupied--;

 /* Bubble down the newly promoted value */

 while((2*index)<queue->noccupied &&
       (queue->results[index]->sortby>queue->results[2*index  ]->sortby ||
        queue->results[index]->sortby>queue->results[2*index+1]->sortby))
   {
    int newindex;
    Result *temp;

    if(queue->results[2*index]->sortby<queue->results[2*index+1]->sortby)
       newindex=2*index;
    else
       newindex=2*index+1;

    temp=queue->results[newindex];
    queue->results[newindex]=queue->results[index];
    queue->results[index]=temp;

    queue->results[index]->queued=index;
    queue->results[newindex]->queued=newindex;

    index=newindex;
   }

 if((2*index)==queue->noccupied &&
    queue->results[index]->sortby>queue->results[2*index]->sortby)
   {
    int newindex;
    Result *temp;

    newindex=2*index;

    temp=queue->results[newindex];
    queue->results[newindex]=queue->results[index];
    queue->results[index]=temp;

    queue->results[index]->queued=index;
    queue->results[newindex]->queued=newindex;
   }

 return(retval);
}
1	/***************************************
2	Queue data type functions.
3
4	Part of the Routino routing software.
5	****************/ /****************
6	This file Copyright 2008-2013 Andrew M. Bishop
7
8	This program is free software: you can redistribute it and/or modify
9	it under the terms of the GNU Affero General Public License as published by
10	the Free Software Foundation, either version 3 of the License, or
11	(at your option) any later version.
12
13	This program is distributed in the hope that it will be useful,
14	but WITHOUT ANY WARRANTY; without even the implied warranty of
15	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16	GNU Affero General Public License for more details.
17
18	You should have received a copy of the GNU Affero General Public License
19	along with this program. If not, see <http://www.gnu.org/licenses/>.
20	***************************************/
21
22
23	#include <string.h>
24	#include <stdlib.h>
25
26	#include "results.h"
27
28
29	/+ A queue of results. +/
30	struct _Queue
31	{
32	int nincrement; /+ The amount to increment the queue when full. +/
33	int nallocated; /+ The number of entries allocated. +/
34	int noccupied; /+ The number of entries occupied. +/
35
36	Result *results; /+ The queue of pointers to results. +*/
37	};
38
39
40	/*++++++++++++++++++++++++++++++++++++++
41	Allocate a new queue.
42
43	Queue *NewQueueList Returns the queue.
44
45	uint8_t log2bins The base 2 logarithm of the initial number of bins in the queue.
46	++++++++++++++++++++++++++++++++++++++*/
47
48	Queue *NewQueueList(uint8_t log2bins)
49	{
50	Queue *queue;
51
52	queue=(Queue*)malloc(sizeof(Queue));
53
54	queue->nincrement=1<<log2bins;
55
56	queue->nallocated=queue->nincrement;
57	queue->noccupied=0;
58
59	queue->results=(Result*)malloc(queue->nallocatedsizeof(Result*));
60
61	return(queue);
62	}
63
64
65	/*++++++++++++++++++++++++++++++++++++++
66	Free a queue.
67
68	Queue *queue The queue to be freed.
69	++++++++++++++++++++++++++++++++++++++*/
70
71	void FreeQueueList(Queue *queue)
72	{
73	free(queue->results);
74
75	free(queue);
76	}
77
78
79	/*++++++++++++++++++++++++++++++++++++++
80	Insert a new item into the queue in the right place.
81
82	The data is stored in a "Binary Heap" http://en.wikipedia.org/wiki/Binary_heap
83	and this operation is adding an item to the heap.
84
85	Queue *queue The queue to insert the result into.
86
87	Result *result The result to insert into the queue.
88
89	score_t score The score to use for sorting the node.
90	++++++++++++++++++++++++++++++++++++++*/
91
92	void InsertInQueue(Queue queue,Result result,score_t score)
93	{
94	int index;
95
96	if(result->queued==NOT_QUEUED)
97	{
98	queue->noccupied++;
99	index=queue->noccupied;
100
101	if(queue->noccupied==queue->nallocated)
102	{
103	queue->nallocated=queue->nallocated+queue->nincrement;
104	queue->results=(Result*)realloc((void)queue->results,queue->nallocatedsizeof(Result));
105	}
106
107	queue->results[index]=result;
108	queue->results[index]->queued=index;
109	}
110	else
111	index=result->queued;
112
113	queue->results[index]->sortby=score;
114
115	/* Bubble up the new value */
116
117	while(index>1 &&
118	queue->results[index]->sortby<queue->results[index/2]->sortby)
119	{
120	int newindex;
121	Result *temp;
122
123	newindex=index/2;
124
125	temp=queue->results[index];
126	queue->results[index]=queue->results[newindex];
127	queue->results[newindex]=temp;
128
129	queue->results[index]->queued=index;
130	queue->results[newindex]->queued=newindex;
131
132	index=newindex;
133	}
134	}
135
136
137	/*++++++++++++++++++++++++++++++++++++++
138	Pop an item from the front of the queue.
139
140	The data is stored in a "Binary Heap" http://en.wikipedia.org/wiki/Binary_heap
141	and this operation is deleting the root item from the heap.
142
143	Result *PopFromQueue Returns the top item.
144
145	Queue *queue The queue to remove the result from.
146	++++++++++++++++++++++++++++++++++++++*/
147
148	Result PopFromQueue(Queue queue)
149	{
150	int index;
151	Result *retval;
152
153	if(queue->noccupied==0)
154	return(NULL);
155
156	retval=queue->results[1];
157	retval->queued=NOT_QUEUED;
158
159	index=1;
160
161	queue->results[index]=queue->results[queue->noccupied];
162
163	queue->noccupied--;
164
165	/* Bubble down the newly promoted value */
166
167	while((2*index)<queue->noccupied &&
168	(queue->results[index]->sortby>queue->results[2*index ]->sortby \|\|
169	queue->results[index]->sortby>queue->results[2*index+1]->sortby))
170	{
171	int newindex;
172	Result *temp;
173
174	if(queue->results[2index]->sortby<queue->results[2index+1]->sortby)
175	newindex=2*index;
176	else
177	newindex=2*index+1;
178
179	temp=queue->results[newindex];
180	queue->results[newindex]=queue->results[index];
181	queue->results[index]=temp;
182
183	queue->results[index]->queued=index;
184	queue->results[newindex]->queued=newindex;
185
186	index=newindex;
187	}
188
189	if((2*index)==queue->noccupied &&
190	queue->results[index]->sortby>queue->results[2*index]->sortby)
191	{
192	int newindex;
193	Result *temp;
194
195	newindex=2*index;
196
197	temp=queue->results[newindex];
198	queue->results[newindex]=queue->results[index];
199	queue->results[index]=temp;
200
201	queue->results[index]->queued=index;
202	queue->results[newindex]->queued=newindex;
203	}
204
205	return(retval);
206	}