1 /***************************************************************************
2  *                                  _   _ ____  _
3  *  Project                     ___| | | |  _ \| |
4  *                             / __| | | | |_) | |
5  *                            | (__| |_| |  _ <| |___
6  *                             \___|\___/|_| \_\_____|
7  *
8  * Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
9  *
10  * This software is licensed as described in the file COPYING, which
11  * you should have received as part of this distribution. The terms
12  * are also available at https://curl.haxx.se/docs/copyright.html.
13  *
14  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15  * copies of the Software, and permit persons to whom the Software is
16  * furnished to do so, under the terms of the COPYING file.
17  *
18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19  * KIND, either express or implied.
20  *
21  ***************************************************************************/
22 
23 #include "curl_setup.h"
24 
25 #include <curl/curl.h>
26 
27 #include "llist.h"
28 #include "curl_memory.h"
29 
30 /* this must be the last include file */
31 #include "memdebug.h"
32 
33 /*
34  * @unittest: 1300
35  */
36 void
37 Curl_llist_init(struct curl_llist *l, curl_llist_dtor dtor)
38 {
39   l->size = 0;
40   l->dtor = dtor;
41   l->head = NULL;
42   l->tail = NULL;
43 }
44 
45 /*
46  * Curl_llist_insert_next()
47  *
48  * Inserts a new list element after the given one 'e'. If the given existing
49  * entry is NULL and the list already has elements, the new one will be
50  * inserted first in the list.
51  *
52  * The 'ne' argument should be a pointer into the object to store.
53  *
54  * @unittest: 1300
55  */
56 void
57 Curl_llist_insert_next(struct curl_llist *list, struct curl_llist_element *e,
58                        const void *p,
59                        struct curl_llist_element *ne)
60 {
61   ne->ptr = (void *) p;
62   if(list->size == 0) {
63     list->head = ne;
64     list->head->prev = NULL;
65     list->head->next = NULL;
66     list->tail = ne;
67   }
68   else {
69     /* if 'e' is NULL here, we insert the new element first in the list */
70     ne->next = e?e->next:list->head;
71     ne->prev = e;
72     if(!e) {
73       list->head->prev = ne;
74       list->head = ne;
75     }
76     else if(e->next) {
77       e->next->prev = ne;
78     }
79     else {
80       list->tail = ne;
81     }
82     if(e)
83       e->next = ne;
84   }
85 
86   ++list->size;
87 }
88 
89 /*
90  * @unittest: 1300
91  */
92 void
93 Curl_llist_remove(struct curl_llist *list, struct curl_llist_element *e,
94                   void *user)
95 {
96   void *ptr;
97   if(e == NULL || list->size == 0)
98     return;
99 
100   if(e == list->head) {
101     list->head = e->next;
102 
103     if(list->head == NULL)
104       list->tail = NULL;
105     else
106       e->next->prev = NULL;
107   }
108   else {
109     if(!e->prev)
110       list->head = e->next;
111     else
112       e->prev->next = e->next;
113 
114     if(!e->next)
115       list->tail = e->prev;
116     else
117       e->next->prev = e->prev;
118   }
119 
120   ptr = e->ptr;
121 
122   e->ptr  = NULL;
123   e->prev = NULL;
124   e->next = NULL;
125 
126   --list->size;
127 
128   /* call the dtor() last for when it actually frees the 'e' memory itself */
129   if(list->dtor)
130     list->dtor(user, ptr);
131 }
132 
133 void
134 Curl_llist_destroy(struct curl_llist *list, void *user)
135 {
136   if(list) {
137     while(list->size > 0)
138       Curl_llist_remove(list, list->tail, user);
139   }
140 }
141 
142 size_t
143 Curl_llist_count(struct curl_llist *list)
144 {
145   return list->size;
146 }
147 
148 /*
149  * @unittest: 1300
150  */
151 void Curl_llist_move(struct curl_llist *list, struct curl_llist_element *e,
152                      struct curl_llist *to_list,
153                      struct curl_llist_element *to_e)
154 {
155   /* Remove element from list */
156   if(e == NULL || list->size == 0)
157     return;
158 
159   if(e == list->head) {
160     list->head = e->next;
161 
162     if(list->head == NULL)
163       list->tail = NULL;
164     else
165       e->next->prev = NULL;
166   }
167   else {
168     e->prev->next = e->next;
169     if(!e->next)
170       list->tail = e->prev;
171     else
172       e->next->prev = e->prev;
173   }
174 
175   --list->size;
176 
177   /* Add element to to_list after to_e */
178   if(to_list->size == 0) {
179     to_list->head = e;
180     to_list->head->prev = NULL;
181     to_list->head->next = NULL;
182     to_list->tail = e;
183   }
184   else {
185     e->next = to_e->next;
186     e->prev = to_e;
187     if(to_e->next) {
188       to_e->next->prev = e;
189     }
190     else {
191       to_list->tail = e;
192     }
193     to_e->next = e;
194   }
195 
196   ++to_list->size;
197 }
198