1 /* $OpenBSD: queue.c,v 1.6 2011/07/08 01:20:24 tedu Exp $ */
2
3 /*-
4 * Copyright (c) 1999 James Howard and Dag-Erling Co�dan Sm�rgrav
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 /*
30 * A really poor man's queue. It does only what it has to and gets out of
31 * Dodge.
32 */
33
34 #include <sys/param.h>
35
36 #include <stdlib.h>
37 #include <string.h>
38
39 #include "grep.h"
40
41 typedef struct queue {
42 struct queue *next;
43 str_t data;
44 } queue_t;
45
46 static queue_t *q_head, *q_tail;
47 static int count;
48
49 static queue_t *dequeue(void);
50
51 void
initqueue(void)52 initqueue(void)
53 {
54 q_head = q_tail = NULL;
55 }
56
57 static void
free_item(queue_t * item)58 free_item(queue_t *item)
59 {
60 free(item);
61 }
62
63 void
enqueue(str_t * x)64 enqueue(str_t *x)
65 {
66 queue_t *item;
67
68 item = grep_malloc(sizeof *item + x->len);
69 item->data.len = x->len;
70 item->data.line_no = x->line_no;
71 item->data.off = x->off;
72 item->data.dat = (char *)item + sizeof *item;
73 memcpy(item->data.dat, x->dat, x->len);
74 item->data.file = x->file;
75 item->next = NULL;
76
77 if (!q_head) {
78 q_head = q_tail = item;
79 } else {
80 q_tail->next = item;
81 q_tail = item;
82 }
83
84 if (++count > Bflag)
85 free_item(dequeue());
86 }
87
88 static queue_t *
dequeue(void)89 dequeue(void)
90 {
91 queue_t *item;
92
93 if (q_head == NULL)
94 return NULL;
95
96 --count;
97 item = q_head;
98 q_head = item->next;
99 if (q_head == NULL)
100 q_tail = NULL;
101 return item;
102 }
103
104 void
printqueue(void)105 printqueue(void)
106 {
107 queue_t *item;
108
109 while ((item = dequeue()) != NULL) {
110 printline(&item->data, '-', NULL);
111 free_item(item);
112 }
113 }
114
115 void
clearqueue(void)116 clearqueue(void)
117 {
118 queue_t *item;
119
120 while ((item = dequeue()) != NULL)
121 free_item(item);
122 }
123