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Annotation of embedaddon/istgt/src/istgt_queue.c, revision 1.1.1.1

1.1       misho       1: /*
                      2:  * Copyright (C) 2008-2010 Daisuke Aoyama <aoyama@peach.ne.jp>.
                      3:  * All rights reserved.
                      4:  *
                      5:  * Redistribution and use in source and binary forms, with or without
                      6:  * modification, are permitted provided that the following conditions
                      7:  * are met:
                      8:  * 1. Redistributions of source code must retain the above copyright
                      9:  *    notice, this list of conditions and the following disclaimer.
                     10:  * 2. Redistributions in binary form must reproduce the above copyright
                     11:  *    notice, this list of conditions and the following disclaimer in the
                     12:  *    documentation and/or other materials provided with the distribution.
                     13:  *
                     14:  * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
                     15:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     16:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     17:  * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
                     18:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     19:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     20:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     21:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     22:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     23:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     24:  * SUCH DAMAGE.
                     25:  *
                     26:  */
                     27: 
                     28: #ifdef HAVE_CONFIG_H
                     29: #include "config.h"
                     30: #endif
                     31: 
                     32: #include <inttypes.h>
                     33: #include <stdint.h>
                     34: 
                     35: #include <stdlib.h>
                     36: #include <string.h>
                     37: 
                     38: #include "istgt_misc.h"
                     39: #include "istgt_queue.h"
                     40: 
                     41: int
                     42: istgt_queue_init(ISTGT_QUEUE_Ptr head)
                     43: {
                     44:        if (head == NULL)
                     45:                return -1;
                     46:        head->prev = NULL;
                     47:        head->next = NULL;
                     48:        head->elem = NULL;
                     49:        return 0;
                     50: }
                     51: 
                     52: void
                     53: istgt_queue_destroy(ISTGT_QUEUE_Ptr head)
                     54: {
                     55:        ISTGT_QUEUE_Ptr qp;
                     56:        ISTGT_QUEUE_Ptr next;
                     57: 
                     58:        if (head == NULL)
                     59:                return;
                     60:        for (qp = head->next; qp != NULL && qp != head; qp = next) {
                     61:                next = qp->next;
                     62:                free(qp);
                     63:        }
                     64:        head->next = NULL;
                     65:        head->prev = NULL;
                     66: }
                     67: 
                     68: int
                     69: istgt_queue_count(ISTGT_QUEUE_Ptr head)
                     70: {
                     71:        ISTGT_QUEUE_Ptr qp;
                     72:        int num;
                     73: 
                     74:        if (head == NULL)
                     75:                return 0;
                     76:        num = 0;
                     77:        for (qp = head->next; qp != NULL && qp != head; qp = qp->next) {
                     78:                num++;
                     79:        }
                     80:        return num;
                     81: }
                     82: 
                     83: int
                     84: istgt_queue_enqueue(ISTGT_QUEUE_Ptr head, void *elem)
                     85: {
                     86:        ISTGT_QUEUE_Ptr qp;
                     87:        ISTGT_QUEUE_Ptr tail;
                     88: 
                     89:        if (head == NULL)
                     90:                return -1;
                     91:        qp = xmalloc(sizeof *qp);
                     92:        memset(qp, 0, sizeof *qp);
                     93: 
                     94:        qp->elem = elem;
                     95: 
                     96:        tail = head->prev;
                     97:        if (tail == NULL) {
                     98:                head->next = qp;
                     99:                head->prev = qp;
                    100:                qp->next = head;
                    101:                qp->prev = head;
                    102:        } else {
                    103:                tail->next = qp;
                    104:                head->prev = qp;
                    105:                qp->next = head;
                    106:                qp->prev = tail;
                    107:        }
                    108:        return 0;
                    109: }
                    110: 
                    111: void *
                    112: istgt_queue_dequeue(ISTGT_QUEUE_Ptr head)
                    113: {
                    114:        ISTGT_QUEUE_Ptr first;
                    115:        ISTGT_QUEUE_Ptr next;
                    116:        void *elem;
                    117: 
                    118:        if (head == NULL)
                    119:                return NULL;
                    120:        first = head->next;
                    121:        if (first == NULL || first == head) {
                    122:                return NULL;
                    123:        } else {
                    124:                elem = first->elem;
                    125:                next = first->next;
                    126:                xfree(first);
                    127:                if (next == NULL) {
                    128:                        head->next = NULL;
                    129:                        head->prev = NULL;
                    130:                } else {
                    131:                        head->next = next;
                    132:                        next->prev = head;
                    133:                }
                    134:        }
                    135:        return elem;
                    136: }
                    137: 
                    138: int
                    139: istgt_queue_enqueue_first(ISTGT_QUEUE_Ptr head, void *elem)
                    140: {
                    141:        ISTGT_QUEUE_Ptr qp;
                    142:        ISTGT_QUEUE_Ptr first;
                    143: 
                    144:        if (head == NULL)
                    145:                return -1;
                    146:        qp = xmalloc(sizeof *qp);
                    147:        memset(qp, 0, sizeof *qp);
                    148: 
                    149:        qp->elem = elem;
                    150: 
                    151:        first = head->next;
                    152:        if (first == NULL || first == head) {
                    153:                head->next = qp;
                    154:                head->prev = qp;
                    155:                qp->next = head;
                    156:                qp->prev = head;
                    157:        } else {
                    158:                head->next = qp;
                    159:                first->prev = qp;
                    160:                qp->next = first;
                    161:                qp->prev = head;
                    162:        }
                    163:        return 0;
                    164: }