1 /* $NetBSD: queue.c,v 1.5 2011/08/31 16:24:57 plunky Exp $ */
2 /* $FreeBSD$ */
3
4 /*-
5 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
6 *
7 * Copyright (c) 1999 James Howard and Dag-Erling Coïdan Smørgrav
8 * All rights reserved.
9 * Copyright (c) 2020 Kyle Evans <[email protected]>
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 /*
34 * A really poor man's queue. It does only what it has to and gets out of
35 * Dodge. It is used in place of <sys/queue.h> to get a better performance.
36 */
37
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40
41 #include <sys/param.h>
42 #include <sys/queue.h>
43
44 #include <stdlib.h>
45 #include <string.h>
46
47 #include "grep.h"
48
49 typedef struct str qentry_t;
50
51 static long long filled;
52 static qentry_t *qend, *qpool;
53
54 /*
55 * qnext is the next entry to populate. qlist is where the list actually
56 * starts, for the purposes of printing.
57 */
58 static qentry_t *qlist, *qnext;
59
60 void
initqueue(void)61 initqueue(void)
62 {
63
64 qlist = qnext = qpool = grep_calloc(Bflag, sizeof(*qpool));
65 qend = qpool + (Bflag - 1);
66 }
67
68 static qentry_t *
advqueue(qentry_t * itemp)69 advqueue(qentry_t *itemp)
70 {
71
72 if (itemp == qend)
73 return (qpool);
74 return (itemp + 1);
75 }
76
77 /*
78 * Enqueue another line; return true if we've dequeued a line as a result
79 */
80 bool
enqueue(struct str * x)81 enqueue(struct str *x)
82 {
83 qentry_t *item;
84 bool rotated;
85
86 item = qnext;
87 qnext = advqueue(qnext);
88 rotated = false;
89
90 if (filled < Bflag) {
91 filled++;
92 } else if (filled == Bflag) {
93 /* We had already filled up coming in; just rotate. */
94 qlist = advqueue(qlist);
95 rotated = true;
96 free(item->dat);
97 }
98 /* len + 1 for NUL-terminator */
99 item->dat = grep_malloc(sizeof(char) * x->len + 1);
100 item->len = x->len;
101 item->line_no = x->line_no;
102 item->boff = x->boff;
103 item->off = x->off;
104 memcpy(item->dat, x->dat, x->len);
105 item->dat[x->len] = '\0';
106 item->file = x->file;
107
108 return (rotated);
109 }
110
111 void
printqueue(void)112 printqueue(void)
113 {
114 qentry_t *item;
115
116 item = qlist;
117 do {
118 /* Buffer must have ended early. */
119 if (item->dat == NULL)
120 break;
121
122 grep_printline(item, '-');
123 free(item->dat);
124 item->dat = NULL;
125 item = advqueue(item);
126 } while (item != qlist);
127
128 qlist = qnext = qpool;
129 filled = 0;
130 }
131
132 void
clearqueue(void)133 clearqueue(void)
134 {
135 qentry_t *item;
136
137 item = qlist;
138 do {
139 free(item->dat);
140 item->dat = NULL;
141 item = advqueue(item);
142 } while (item != qlist);
143
144 qlist = qnext = qpool;
145 filled = 0;
146 }
147