1 /* $OpenBSD: queue.c,v 1.6 2011/07/08 01:20:24 tedu 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 <sys/param.h> 35 36 #include <stdlib.h> 37 #include <string.h> 38 39 #include "grep.h" 40 41 typedef struct queue { 42 struct queue *next; 43 str_t data; 44 } queue_t; 45 46 static queue_t *q_head, *q_tail; 47 static int count; 48 49 static queue_t *dequeue(void); 50 51 void 52 initqueue(void) 53 { 54 q_head = q_tail = NULL; 55 } 56 57 static void 58 free_item(queue_t *item) 59 { 60 free(item); 61 } 62 63 void 64 enqueue(str_t *x) 65 { 66 queue_t *item; 67 68 item = grep_malloc(sizeof *item + x->len); 69 item->data.len = x->len; 70 item->data.line_no = x->line_no; 71 item->data.off = x->off; 72 item->data.dat = (char *)item + sizeof *item; 73 memcpy(item->data.dat, x->dat, x->len); 74 item->data.file = x->file; 75 item->next = NULL; 76 77 if (!q_head) { 78 q_head = q_tail = item; 79 } else { 80 q_tail->next = item; 81 q_tail = item; 82 } 83 84 if (++count > Bflag) 85 free_item(dequeue()); 86 } 87 88 static queue_t * 89 dequeue(void) 90 { 91 queue_t *item; 92 93 if (q_head == NULL) 94 return NULL; 95 96 --count; 97 item = q_head; 98 q_head = item->next; 99 if (q_head == NULL) 100 q_tail = NULL; 101 return item; 102 } 103 104 void 105 printqueue(void) 106 { 107 queue_t *item; 108 109 while ((item = dequeue()) != NULL) { 110 printline(&item->data, '-', NULL); 111 free_item(item); 112 } 113 } 114 115 void 116 clearqueue(void) 117 { 118 queue_t *item; 119 120 while ((item = dequeue()) != NULL) 121 free_item(item); 122 } 123