fifo.c

来自「Development tools and sources fifo.c」· C语言 代码 · 共 154 行

/*
      2  * CDDL HEADER START
      3  *
      4  * The contents of this file are subject to the terms of the
      5  * Common Development and Distribution License, Version 1.0 only
      6  * (the "License").  You may not use this file except in compliance
      7  * with the License.
      8  *
      9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
     10  * or http://www.opensolaris.org/os/licensing.
     11  * See the License for the specific language governing permissions
     12  * and limitations under the License.
     13  *
     14  * When distributing Covered Code, include this CDDL HEADER in each
     15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     16  * If applicable, add the following below this CDDL HEADER, with the
     17  * fields enclosed by brackets "[]" replaced with your own identifying
     18  * information: Portions Copyright [yyyy] [name of copyright owner]
     19  *
     20  * CDDL HEADER END
     21  */
     22 /*
     23  * Copyright 2002 Sun Microsystems, Inc.  All rights reserved.
     24  * Use is subject to license terms.
     25  */
     26 
     27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
     28 
     29 /*
     30  * Routines for manipulating a FIFO queue
     31  */
     32 
     33 #include <stdlib.h>
     34 
     35 #include "fifo.h"
     36 #include "memory.h"
     37 
     38 typedef struct fifonode {
     39 	void *fn_data;
     40 	struct fifonode *fn_next;
     41 } fifonode_t;
     42 
     43 struct fifo {
     44 	fifonode_t *f_head;
     45 	fifonode_t *f_tail;
     46 };
     47 
     48 fifo_t *
     49 fifo_new(void)
     50 {
     51 	fifo_t *f;
     52 
     53 	f = xcalloc(sizeof (fifo_t));
     54 
     55 	return (f);
     56 }
     57 
     58 /* Add to the end of the fifo */
     59 void
     60 fifo_add(fifo_t *f, void *data)
     61 {
     62 	fifonode_t *fn = xmalloc(sizeof (fifonode_t));
     63 
     64 	fn->fn_data = data;
     65 	fn->fn_next = NULL;
     66 
     67 	if (f->f_tail == NULL)
     68 		f->f_head = f->f_tail = fn;
     69 	else {
     70 		f->f_tail->fn_next = fn;
     71 		f->f_tail = fn;
     72 	}
     73 }
     74 
     75 /* Remove from the front of the fifo */
     76 void *
     77 fifo_remove(fifo_t *f)
     78 {
     79 	fifonode_t *fn;
     80 	void *data;
     81 
     82 	if ((fn = f->f_head) == NULL)
     83 		return (NULL);
     84 
     85 	data = fn->fn_data;
     86 	if ((f->f_head = fn->fn_next) == NULL)
     87 		f->f_tail = NULL;
     88 
     89 	free(fn);
     90 
     91 	return (data);
     92 }
     93 
     94 /*ARGSUSED*/
     95 static void
     96 fifo_nullfree(void *arg)
     97 {
     98 	/* this function intentionally left blank */
     99 }
    100 
    101 /* Free an entire fifo */
    102 void
    103 fifo_free(fifo_t *f, void (*freefn)(void *))
    104 {
    105 	fifonode_t *fn = f->f_head;
    106 	fifonode_t *tmp;
    107 
    108 	if (freefn == NULL)
    109 		freefn = fifo_nullfree;
    110 
    111 	while (fn) {
    112 		(*freefn)(fn->fn_data);
    113 
    114 		tmp = fn;
    115 		fn = fn->fn_next;
    116 		free(tmp);
    117 	}
    118 
    119 	free(f);
    120 }
    121 
    122 int
    123 fifo_len(fifo_t *f)
    124 {
    125 	fifonode_t *fn;
    126 	int i;
    127 
    128 	for (i = 0, fn = f->f_head; fn; fn = fn->fn_next, i++);
    129 
    130 	return (i);
    131 }
    132 
    133 int
    134 fifo_empty(fifo_t *f)
    135 {
    136 	return (f->f_head == NULL);
    137 }
    138 
    139 int
    140 fifo_iter(fifo_t *f, int (*iter)(void *data, void *arg), void *arg)
    141 {
    142 	fifonode_t *fn;
    143 	int rc;
    144 	int ret = 0;
    145 
    146 	for (fn = f->f_head; fn; fn = fn->fn_next) {
    147 		if ((rc = iter(fn->fn_data, arg)) < 0)
    148 			return (-1);
    149 		ret += rc;
    150 	}
    151 
    152 	return (ret);
    153 }
    154