usr.bin/grep/queue.c

   1 /*      $NetBSD: queue.c,v 1.6 2003/11/08 17:24:07 cjep Exp $   */
   2
   3 /*-
   4  * Copyright (c) 1999 James Howard and Dag-Erling Coïdan Smørgrav
   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 #include <sys/cdefs.h>
  31 #ifndef lint
  32 __RCSID("$NetBSD: queue.c,v 1.6 2003/11/08 17:24:07 cjep Exp $");
  33 #endif /* not lint */
  34
  35 /*
  36  * A really poor man's queue.  It does only what it has to and gets out of
  37  * Dodge.
  38  */
  39
  40 #include <sys/param.h>
  41
  42 #include <stdlib.h>
  43 #include <string.h>
  44
  45 #include "grep.h"
  46
  47 typedef struct queue {
  48         struct queue *next;
  49         str_t data;
  50 } queue_t;
  51
  52 static queue_t *q_head, *q_tail;
  53 static int count;
  54
  55 static queue_t *dequeue(void);
  56
  57 void
  58 initqueue(void)
  59 {
  60         q_head = q_tail = NULL;
  61 }
  62
  63 static void
  64 free_item(queue_t *item)
  65 {
  66         free(item);
  67 }
  68
  69 void
  70 enqueue(str_t *x)
  71 {
  72         queue_t *item;
  73
  74         item = grep_malloc(sizeof *item + x->len);
  75         item->data.len = x->len;
  76         item->data.line_no = x->line_no;
  77         item->data.off = x->off;
  78         item->data.dat = (char *)item + sizeof *item;
  79         memcpy(item->data.dat, x->dat, x->len);
  80         item->data.file = x->file;
  81         item->next = NULL;
  82
  83         if (!q_head) {
  84                 q_head = q_tail = item;
  85         } else {
  86                 q_tail->next = item;
  87                 q_tail = item;
  88         }
  89
  90         if (++count > Bflag)
  91                 free_item(dequeue());
  92 }
  93
  94 static queue_t *
  95 dequeue(void)
  96 {
  97         queue_t *item;
  98
  99         if (q_head == NULL)
 100                 return NULL;
 101
 102         --count;
 103         item = q_head;
 104         q_head = item->next;
 105         if (q_head == NULL)
 106                 q_tail = NULL;
 107         return item;
 108 }
 109
 110 void
 111 printqueue(void)
 112 {
 113         queue_t *item;
 114
 115         while ((item = dequeue()) != NULL) {
 116                 printline(&item->data, fn_dashchar, (regmatch_t *)NULL, 0);
 117                 free_item(item);
 118         }
 119 }
 120
 121 void
 122 clearqueue(void)
 123 {
 124         queue_t *item;
 125
 126         while ((item = dequeue()) != NULL)
 127                 free_item(item);
 128 }