bin/grep/queue.c

   1 /*      $NetBSD: queue.c,v 1.5 2011/08/31 16:24:57 plunky Exp $ */
   2 /*      $FreeBSD$       */
   3
   4 /*-
   5  * Copyright (c) 1999 James Howard and Dag-Erling Coïdan Smørgrav
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 /*
  31  * A really poor man's queue.  It does only what it has to and gets out of
  32  * Dodge.  It is used in place of <sys/queue.h> to get a better performance.
  33  */
  34
  35 #include <sys/param.h>
  36 #include <sys/queue.h>
  37
  38 #include <stdlib.h>
  39 #include <string.h>
  40
  41 #include "grep.h"
  42
  43 struct qentry {
  44         STAILQ_ENTRY(qentry)    list;
  45         struct str              data;
  46 };
  47
  48 static STAILQ_HEAD(, qentry)    queue = STAILQ_HEAD_INITIALIZER(queue);
  49 static long long                count;
  50
  51 static struct qentry    *dequeue(void);
  52
  53 /*
  54  * Enqueue another line; return true if we've dequeued a line as a result
  55  */
  56 bool
  57 enqueue(struct str *x)
  58 {
  59         struct qentry *item;
  60
  61         item = grep_malloc(sizeof(struct qentry));
  62         item->data.dat = grep_malloc(sizeof(char) * x->len);
  63         item->data.len = x->len;
  64         item->data.line_no = x->line_no;
  65         item->data.boff = x->boff;
  66         item->data.off = x->off;
  67         memcpy(item->data.dat, x->dat, x->len);
  68         item->data.file = x->file;
  69
  70         STAILQ_INSERT_TAIL(&queue, item, list);
  71
  72         if (++count > Bflag) {
  73                 item = dequeue();
  74                 free(item->data.dat);
  75                 free(item);
  76                 return (true);
  77         }
  78         return (false);
  79 }
  80
  81 static struct qentry *
  82 dequeue(void)
  83 {
  84         struct qentry *item;
  85
  86         item = STAILQ_FIRST(&queue);
  87         if (item == NULL)
  88                 return (NULL);
  89
  90         STAILQ_REMOVE_HEAD(&queue, list);
  91         --count;
  92         return (item);
  93 }
  94
  95 void
  96 printqueue(void)
  97 {
  98         struct qentry *item;
  99
 100         while ((item = dequeue()) != NULL) {
 101                 grep_printline(&item->data, '-');
 102                 free(item->data.dat);
 103                 free(item);
 104         }
 105 }
 106
 107 void
 108 clearqueue(void)
 109 {
 110         struct qentry *item;
 111
 112         while ((item = dequeue()) != NULL) {
 113                 free(item->data.dat);
 114                 free(item);
 115         }
 116 }