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 Sm��rgrav
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
45typedef struct str		qentry_t;
46
47static long long		filled;
48static 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 */
54static qentry_t		*qlist, *qnext;
55
56void
57initqueue(void)
58{
59
60	qlist = qnext = qpool = grep_calloc(Bflag, sizeof(*qpool));
61	qend = qpool + (Bflag - 1);
62}
63
64static qentry_t *
65advqueue(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 */
76bool
77enqueue(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
107void
108printqueue(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
128void
129clearqueue(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