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1 /***************************************************************************
2  *                                  _   _ ____  _
3  *  Project                     ___| | | |  _ \| |
4  *                             / __| | | | |_) | |
5  *                            | (__| |_| |  _ <| |___
6  *                             \___|\___/|_| \_\_____|
7  *
8  * Copyright (C) 1998 - 2016, 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 "slist.h"
28 
29 /* The last #include files should be: */
30 #include "curl_memory.h"
31 #include "memdebug.h"
32 
33 /* returns last node in linked list */
slist_get_last(struct curl_slist * list)34 static struct curl_slist *slist_get_last(struct curl_slist *list)
35 {
36   struct curl_slist     *item;
37 
38   /* if caller passed us a NULL, return now */
39   if(!list)
40     return NULL;
41 
42   /* loop through to find the last item */
43   item = list;
44   while(item->next) {
45     item = item->next;
46   }
47   return item;
48 }
49 
50 /*
51  * Curl_slist_append_nodup() appends a string to the linked list. Rather than
52  * copying the string in dynamic storage, it takes its ownership. The string
53  * should have been malloc()ated. Curl_slist_append_nodup always returns
54  * the address of the first record, so that you can use this function as an
55  * initialization function as well as an append function.
56  * If an error occurs, NULL is returned and the string argument is NOT
57  * released.
58  */
Curl_slist_append_nodup(struct curl_slist * list,char * data)59 struct curl_slist *Curl_slist_append_nodup(struct curl_slist *list, char *data)
60 {
61   struct curl_slist     *last;
62   struct curl_slist     *new_item;
63 
64   DEBUGASSERT(data);
65 
66   new_item = malloc(sizeof(struct curl_slist));
67   if(!new_item)
68     return NULL;
69 
70   new_item->next = NULL;
71   new_item->data = data;
72 
73   /* if this is the first item, then new_item *is* the list */
74   if(!list)
75     return new_item;
76 
77   last = slist_get_last(list);
78   last->next = new_item;
79   return list;
80 }
81 
82 /*
83  * curl_slist_append() appends a string to the linked list. It always returns
84  * the address of the first record, so that you can use this function as an
85  * initialization function as well as an append function. If you find this
86  * bothersome, then simply create a separate _init function and call it
87  * appropriately from within the program.
88  */
curl_slist_append(struct curl_slist * list,const char * data)89 struct curl_slist *curl_slist_append(struct curl_slist *list,
90                                      const char *data)
91 {
92   char *dupdata = strdup(data);
93 
94   if(!dupdata)
95     return NULL;
96 
97   list = Curl_slist_append_nodup(list, dupdata);
98   if(!list)
99     free(dupdata);
100 
101   return list;
102 }
103 
104 /*
105  * Curl_slist_duplicate() duplicates a linked list. It always returns the
106  * address of the first record of the cloned list or NULL in case of an
107  * error (or if the input list was NULL).
108  */
Curl_slist_duplicate(struct curl_slist * inlist)109 struct curl_slist *Curl_slist_duplicate(struct curl_slist *inlist)
110 {
111   struct curl_slist *outlist = NULL;
112   struct curl_slist *tmp;
113 
114   while(inlist) {
115     tmp = curl_slist_append(outlist, inlist->data);
116 
117     if(!tmp) {
118       curl_slist_free_all(outlist);
119       return NULL;
120     }
121 
122     outlist = tmp;
123     inlist = inlist->next;
124   }
125   return outlist;
126 }
127 
128 /* be nice and clean up resources */
curl_slist_free_all(struct curl_slist * list)129 void curl_slist_free_all(struct curl_slist *list)
130 {
131   struct curl_slist     *next;
132   struct curl_slist     *item;
133 
134   if(!list)
135     return;
136 
137   item = list;
138   do {
139     next = item->next;
140     Curl_safefree(item->data);
141     free(item);
142     item = next;
143   } while(next);
144 }
145