trunk/src/queue.c

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

 Part of the Routino routing software.
 ******************/ /******************
 This file Copyright 2008-2011 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 <sys/types.h>
#include <string.h>
#include <stdlib.h>

#include "results.h"


/*+ The size of the increment to the allocated memory. +*/
#define QUEUE_INCREMENT 1024


/*+ A queue of results. +*/
struct _Queue
{
 uint32_t nallocated;           /*+ The number of entries allocated. +*/
 uint32_t noccupied;            /*+ The number of entries occupied. +*/

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


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

  Queue *NewQueueList Returns the queue.
  ++++++++++++++++++++++++++++++++++++++*/

Queue *NewQueueList(void)
{
 Queue *queue;

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

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

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

 return(queue);
}


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

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

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

 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.
  ++++++++++++++++++++++++++++++++++++++*/

void InsertInQueue(Queue *queue,Result *result)
{
 uint32_t index;

 if(result->queued==NOT_QUEUED)
   {
    if(queue->noccupied==queue->nallocated)
      {
       queue->nallocated=queue->nallocated+QUEUE_INCREMENT;
       queue->data=(Result**)realloc((void*)queue->data,queue->nallocated*sizeof(Result*));
      }

    index=queue->noccupied;
    queue->noccupied++;

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

 /* Bubble up the new value */

 while(index>0)
   {
    uint32_t newindex;
    Result *temp;

    newindex=(index-1)/2;

    if(queue->data[index]->sortby>=queue->data[newindex]->sortby)
       break;

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

    queue->data[index]->queued=index;
    queue->data[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)
{
 uint32_t index;
 Result *retval;

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

 retval=queue->data[0];
 retval->queued=NOT_QUEUED;

 index=0;
 queue->noccupied--;

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

 /* Bubble down the newly promoted value */

 while((2*index+2)<queue->noccupied)
   {
    uint32_t newindex;
    Result *temp;

    newindex=2*index+1;

    if(queue->data[newindex]->sortby>queue->data[newindex+1]->sortby)
       newindex=newindex+1;

    if(queue->data[index]->sortby<=queue->data[newindex]->sortby)
       break;

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

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

    index=newindex;
   }

 if((2*index+2)==queue->noccupied)
   {
    uint32_t newindex;
    Result *temp;

    newindex=2*index+1;

    if(queue->data[index]->sortby<=queue->data[newindex]->sortby)
       ; /* break */
    else
      {
       temp=queue->data[newindex];
       queue->data[newindex]=queue->data[index];
       queue->data[index]=temp;

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

 return(retval);
}
1	/***************************************
2	Queue data type functions.
3
4	Part of the Routino routing software.
5	****************/ /****************
6	This file Copyright 2008-2011 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 <sys/types.h>
24	#include <string.h>
25	#include <stdlib.h>
26
27	#include "results.h"
28
29
30	/+ The size of the increment to the allocated memory. +/
31	#define QUEUE_INCREMENT 1024
32
33
34	/+ A queue of results. +/
35	struct _Queue
36	{
37	uint32_t nallocated; /+ The number of entries allocated. +/
38	uint32_t noccupied; /+ The number of entries occupied. +/
39
40	Result *data; /+ The queue of pointers to results. +*/
41	};
42
43
44	/*++++++++++++++++++++++++++++++++++++++
45	Allocate a new queue.
46
47	Queue *NewQueueList Returns the queue.
48	++++++++++++++++++++++++++++++++++++++*/
49
50	Queue *NewQueueList(void)
51	{
52	Queue *queue;
53
54	queue=(Queue*)malloc(sizeof(Queue));
55
56	queue->nallocated=QUEUE_INCREMENT;
57	queue->noccupied=0;
58
59	queue->data=(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->data);
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
90	void InsertInQueue(Queue queue,Result result)
91	{
92	uint32_t index;
93
94	if(result->queued==NOT_QUEUED)
95	{
96	if(queue->noccupied==queue->nallocated)
97	{
98	queue->nallocated=queue->nallocated+QUEUE_INCREMENT;
99	queue->data=(Result*)realloc((void)queue->data,queue->nallocatedsizeof(Result));
100	}
101
102	index=queue->noccupied;
103	queue->noccupied++;
104
105	queue->data[index]=result;
106	queue->data[index]->queued=index;
107	}
108	else
109	{
110	index=result->queued;
111	}
112
113	/* Bubble up the new value */
114
115	while(index>0)
116	{
117	uint32_t newindex;
118	Result *temp;
119
120	newindex=(index-1)/2;
121
122	if(queue->data[index]->sortby>=queue->data[newindex]->sortby)
123	break;
124
125	temp=queue->data[index];
126	queue->data[index]=queue->data[newindex];
127	queue->data[newindex]=temp;
128
129	queue->data[index]->queued=index;
130	queue->data[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	uint32_t index;
151	Result *retval;
152
153	if(queue->noccupied==0)
154	return(NULL);
155
156	retval=queue->data[0];
157	retval->queued=NOT_QUEUED;
158
159	index=0;
160	queue->noccupied--;
161
162	queue->data[index]=queue->data[queue->noccupied];
163
164	/* Bubble down the newly promoted value */
165
166	while((2*index+2)<queue->noccupied)
167	{
168	uint32_t newindex;
169	Result *temp;
170
171	newindex=2*index+1;
172
173	if(queue->data[newindex]->sortby>queue->data[newindex+1]->sortby)
174	newindex=newindex+1;
175
176	if(queue->data[index]->sortby<=queue->data[newindex]->sortby)
177	break;
178
179	temp=queue->data[newindex];
180	queue->data[newindex]=queue->data[index];
181	queue->data[index]=temp;
182
183	queue->data[index]->queued=index;
184	queue->data[newindex]->queued=newindex;
185
186	index=newindex;
187	}
188
189	if((2*index+2)==queue->noccupied)
190	{
191	uint32_t newindex;
192	Result *temp;
193
194	newindex=2*index+1;
195
196	if(queue->data[index]->sortby<=queue->data[newindex]->sortby)
197	; /* break */
198	else
199	{
200	temp=queue->data[newindex];
201	queue->data[newindex]=queue->data[index];
202	queue->data[index]=temp;
203
204	queue->data[index]->queued=index;
205	queue->data[newindex]->queued=newindex;
206	}
207	}
208
209	return(retval);
210	}