1 /* $NetBSD: queue.c,v 1.5 2011/08/31 16:24:57 plunky Exp $ */
2
3 /*-
4 * SPDX-License-Identifier: BSD-2-Clause
5 *
6 * Copyright (c) 1999 James Howard and Dag-Erling Smørgrav
7 * All rights reserved.
8 * Copyright (c) 2020 Kyle Evans <kevans@FreeBSD.org>
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 /*
33 * A really poor man's queue. It does only what it has to and gets out of
34 * Dodge. It is used in place of <sys/queue.h> to get a better performance.
35 */
36
37 #include <sys/param.h>
38 #include <sys/queue.h>
39
40 #include <stdlib.h>
41 #include <string.h>
42
43 #include "grep.h"
44
45 typedef struct str qentry_t;
46
47 static long long filled;
48 static qentry_t *qend, *qpool;
49
50 /*
51 * qnext is the next entry to populate. qlist is where the list actually
52 * starts, for the purposes of printing.
53 */
54 static qentry_t *qlist, *qnext;
55
56 void
initqueue(void)57 initqueue(void)
58 {
59
60 qlist = qnext = qpool = grep_calloc(Bflag, sizeof(*qpool));
61 qend = qpool + (Bflag - 1);
62 }
63
64 static qentry_t *
advqueue(qentry_t * itemp)65 advqueue(qentry_t *itemp)
66 {
67
68 if (itemp == qend)
69 return (qpool);
70 return (itemp + 1);
71 }
72
73 /*
74 * Enqueue another line; return true if we've dequeued a line as a result
75 */
76 bool
enqueue(struct str * x)77 enqueue(struct str *x)
78 {
79 qentry_t *item;
80 bool rotated;
81
82 item = qnext;
83 qnext = advqueue(qnext);
84 rotated = false;
85
86 if (filled < Bflag) {
87 filled++;
88 } else if (filled == Bflag) {
89 /* We had already filled up coming in; just rotate. */
90 qlist = advqueue(qlist);
91 rotated = true;
92 free(item->dat);
93 }
94 /* len + 1 for NUL-terminator */
95 item->dat = grep_malloc(sizeof(char) * x->len + 1);
96 item->len = x->len;
97 item->line_no = x->line_no;
98 item->boff = x->boff;
99 item->off = x->off;
100 memcpy(item->dat, x->dat, x->len);
101 item->dat[x->len] = '\0';
102 item->file = x->file;
103
104 return (rotated);
105 }
106
107 void
printqueue(void)108 printqueue(void)
109 {
110 qentry_t *item;
111
112 item = qlist;
113 do {
114 /* Buffer must have ended early. */
115 if (item->dat == NULL)
116 break;
117
118 grep_printline(item, '-');
119 free(item->dat);
120 item->dat = NULL;
121 item = advqueue(item);
122 } while (item != qlist);
123
124 qlist = qnext = qpool;
125 filled = 0;
126 }
127
128 void
clearqueue(void)129 clearqueue(void)
130 {
131 qentry_t *item;
132
133 item = qlist;
134 do {
135 free(item->dat);
136 item->dat = NULL;
137 item = advqueue(item);
138 } while (item != qlist);
139
140 qlist = qnext = qpool;
141 filled = 0;
142 }
143