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Annotation of src/usr.bin/grep/queue.c, Revision 1.6

1.6     ! tedu        1: /*     $OpenBSD: queue.c,v 1.5 2006/02/09 09:54:47 otto Exp $  */
1.3       deraadt     2:
1.1       deraadt     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:  * 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: {
1.4       deraadt    66:        queue_t *item;
1.1       deraadt    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: {
1.4       deraadt    91:        queue_t *item;
1.1       deraadt    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) {
1.6     ! tedu      110:                printline(&item->data, '-', NULL);
1.1       deraadt   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: }