1 /* 2 * Copyright (c) International Business Machines Corp., 2001-2004 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See 12 * the GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 17 */ 18 #include <stdlib.h> 19 #include <assert.h> 20 21 #include "cirlist.h" 22 #include "util.h" 23 24 void init_cirlist(struct cirlist *cl) 25 { 26 cl->count = 0; 27 cl->head = NULL; 28 } 29 30 int cl_empty(struct cirlist *cl) 31 { 32 return !(cl->count); 33 } 34 35 void cl_insert_tail(struct cirlist *cl, cldatatype object) 36 { 37 struct cnode *new = ffsb_malloc(sizeof(struct cnode)); 38 new->obj = object; 39 if (cl->count == 0) { 40 assert(cl->head == NULL); 41 cl->head = new; 42 cl->head->next = cl->head; 43 cl->head->prev = cl->head; 44 cl->count = 1; 45 } else { 46 if (cl->count == 1) { 47 assert(cl->head->next == cl->head); 48 assert(cl->head->prev == cl->head); 49 cl->head->next = new; 50 cl->head->prev = new; 51 new->next = cl->head; 52 new->prev = cl->head; 53 } else { 54 assert(cl->head->next != cl->head); 55 assert(cl->head->prev != cl->head); 56 57 new->next = cl->head; 58 new->prev = (cl->head)->prev; 59 cl->head->prev->next = new; 60 cl->head->prev = new; 61 } 62 cl->count++; 63 } 64 } 65 66 cldatatype cl_remove_head(struct cirlist *cl) 67 { 68 struct cnode *oldhead = NULL; 69 struct cnode *newhead = NULL; 70 cldatatype ret = NULL; 71 72 if (cl->count == 0) { 73 assert(cl->head == NULL); 74 return NULL; 75 } 76 if (cl->count == 1) { 77 assert(cl->head->next == cl->head); 78 assert(cl->head->prev == cl->head); 79 oldhead = cl->head; 80 cl->head = NULL; 81 cl->count = 0; 82 } else if (cl->count == 2) { 83 oldhead = cl->head; 84 newhead = oldhead->next; 85 newhead->next = newhead; 86 newhead->prev = newhead; 87 cl->head = newhead; 88 cl->count = 1; 89 } else { 90 assert(cl->head->next != cl->head); 91 assert(cl->head->prev != cl->head); 92 oldhead = cl->head; 93 newhead = oldhead->next; 94 newhead->prev = oldhead->prev; 95 newhead->prev->next = newhead; 96 cl->head = newhead; 97 cl->count--; 98 } 99 ret = oldhead->obj; 100 oldhead->obj = (void *)(-1); 101 oldhead->next = (void *)(-1); 102 oldhead->prev = (void *)(-1); 103 free(oldhead); 104 105 return ret; 106 } 107
