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/* $OpenBSD: queue.c,v 1.7 2015/01/16 06:40:08 deraadt Exp $ */
/*-
* Copyright (c) 1999 James Howard and Dag-Erling Coïdan Smørgrav
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* A really poor man's queue. It does only what it has to and gets out of
* Dodge.
*/
#include <stdlib.h>
#include <string.h>
#include "grep.h"
typedef struct queue {
struct queue *next;
str_t data;
} queue_t;
static queue_t *q_head, *q_tail;
static int count;
static queue_t *dequeue(void);
void
initqueue(void)
{
q_head = q_tail = NULL;
}
static void
free_item(queue_t *item)
{
free(item);
}
void
enqueue(str_t *x)
{
queue_t *item;
item = grep_malloc(sizeof *item + x->len);
item->data.len = x->len;
item->data.line_no = x->line_no;
item->data.off = x->off;
item->data.dat = (char *)item + sizeof *item;
memcpy(item->data.dat, x->dat, x->len);
item->data.file = x->file;
item->next = NULL;
if (!q_head) {
q_head = q_tail = item;
} else {
q_tail->next = item;
q_tail = item;
}
if (++count > Bflag)
free_item(dequeue());
}
static queue_t *
dequeue(void)
{
queue_t *item;
if (q_head == NULL)
return NULL;
--count;
item = q_head;
q_head = item->next;
if (q_head == NULL)
q_tail = NULL;
return item;
}
void
printqueue(void)
{
queue_t *item;
while ((item = dequeue()) != NULL) {
printline(&item->data, '-', NULL);
free_item(item);
}
}
void
clearqueue(void)
{
queue_t *item;
while ((item = dequeue()) != NULL)
free_item(item);
}
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