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/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 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 * 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 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 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 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