1 /* $OpenBSD: queue.c,v 1.7 2015/01/16 06:40:08 deraadt Exp $ */ 2 3 /*- 4 * Copyright (c) 1999 James Howard and Dag-Erling Co�dan Sm�rgrav 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 /* 30 * A really poor man's queue. It does only what it has to and gets out of 31 * Dodge. 32 */ 33 34 #include <stdlib.h> 35 #include <string.h> 36 37 #include "grep.h" 38 39 typedef struct queue { 40 struct queue *next; 41 str_t data; 42 } queue_t; 43 44 static queue_t *q_head, *q_tail; 45 static int count; 46 47 static queue_t *dequeue(void); 48 49 void 50 initqueue(void) 51 { 52 q_head = q_tail = NULL; 53 } 54 55 static void 56 free_item(queue_t *item) 57 { 58 free(item); 59 } 60 61 void 62 enqueue(str_t *x) 63 { 64 queue_t *item; 65 66 item = grep_malloc(sizeof *item + x->len); 67 item->data.len = x->len; 68 item->data.line_no = x->line_no; 69 item->data.off = x->off; 70 item->data.dat = (char *)item + sizeof *item; 71 memcpy(item->data.dat, x->dat, x->len); 72 item->data.file = x->file; 73 item->next = NULL; 74 75 if (!q_head) { 76 q_head = q_tail = item; 77 } else { 78 q_tail->next = item; 79 q_tail = item; 80 } 81 82 if (++count > Bflag) 83 free_item(dequeue()); 84 } 85 86 static queue_t * 87 dequeue(void) 88 { 89 queue_t *item; 90 91 if (q_head == NULL) 92 return NULL; 93 94 --count; 95 item = q_head; 96 q_head = item->next; 97 if (q_head == NULL) 98 q_tail = NULL; 99 return item; 100 } 101 102 void 103 printqueue(void) 104 { 105 queue_t *item; 106 107 while ((item = dequeue()) != NULL) { 108 printline(&item->data, '-', NULL); 109 free_item(item); 110 } 111 } 112 113 void 114 clearqueue(void) 115 { 116 queue_t *item; 117 118 while ((item = dequeue()) != NULL) 119 free_item(item); 120 } 121