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 <[email protected]>
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/cdefs.h>
38 #include <sys/param.h>
39 #include <sys/queue.h>
40
41 #include <stdlib.h>
42 #include <string.h>
43
44 #include "grep.h"
45
46 typedef struct str qentry_t;
47
48 static long long filled;
49 static qentry_t *qend, *qpool;
50
51 /*
52 * qnext is the next entry to populate. qlist is where the list actually
53 * starts, for the purposes of printing.
54 */
55 static qentry_t *qlist, *qnext;
56
57 void
initqueue(void)58 initqueue(void)
59 {
60
61 qlist = qnext = qpool = grep_calloc(Bflag, sizeof(*qpool));
62 qend = qpool + (Bflag - 1);
63 }
64
65 static qentry_t *
advqueue(qentry_t * itemp)66 advqueue(qentry_t *itemp)
67 {
68
69 if (itemp == qend)
70 return (qpool);
71 return (itemp + 1);
72 }
73
74 /*
75 * Enqueue another line; return true if we've dequeued a line as a result
76 */
77 bool
enqueue(struct str * x)78 enqueue(struct str *x)
79 {
80 qentry_t *item;
81 bool rotated;
82
83 item = qnext;
84 qnext = advqueue(qnext);
85 rotated = false;
86
87 if (filled < Bflag) {
88 filled++;
89 } else if (filled == Bflag) {
90 /* We had already filled up coming in; just rotate. */
91 qlist = advqueue(qlist);
92 rotated = true;
93 free(item->dat);
94 }
95 /* len + 1 for NUL-terminator */
96 item->dat = grep_malloc(sizeof(char) * x->len + 1);
97 item->len = x->len;
98 item->line_no = x->line_no;
99 item->boff = x->boff;
100 item->off = x->off;
101 memcpy(item->dat, x->dat, x->len);
102 item->dat[x->len] = '\0';
103 item->file = x->file;
104
105 return (rotated);
106 }
107
108 void
printqueue(void)109 printqueue(void)
110 {
111 qentry_t *item;
112
113 item = qlist;
114 do {
115 /* Buffer must have ended early. */
116 if (item->dat == NULL)
117 break;
118
119 grep_printline(item, '-');
120 free(item->dat);
121 item->dat = NULL;
122 item = advqueue(item);
123 } while (item != qlist);
124
125 qlist = qnext = qpool;
126 filled = 0;
127 }
128
129 void
clearqueue(void)130 clearqueue(void)
131 {
132 qentry_t *item;
133
134 item = qlist;
135 do {
136 free(item->dat);
137 item->dat = NULL;
138 item = advqueue(item);
139 } while (item != qlist);
140
141 qlist = qnext = qpool;
142 filled = 0;
143 }
144