1DEFINE_STACK_OF(3)                  OpenSSL                 DEFINE_STACK_OF(3)
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NAME

6       DEFINE_STACK_OF, DEFINE_STACK_OF_CONST, DEFINE_SPECIAL_STACK_OF,
7       DEFINE_SPECIAL_STACK_OF_CONST, sk_TYPE_num, sk_TYPE_value, sk_TYPE_new,
8       sk_TYPE_new_null, sk_TYPE_reserve, sk_TYPE_free, sk_TYPE_zero,
9       sk_TYPE_delete, sk_TYPE_delete_ptr, sk_TYPE_push, sk_TYPE_unshift,
10       sk_TYPE_pop, sk_TYPE_shift, sk_TYPE_pop_free, sk_TYPE_insert,
11       sk_TYPE_set, sk_TYPE_find, sk_TYPE_find_ex, sk_TYPE_sort,
12       sk_TYPE_is_sorted, sk_TYPE_dup, sk_TYPE_deep_copy,
13       sk_TYPE_set_cmp_func, sk_TYPE_new_reserve - stack container
14

SYNOPSIS

16        #include <openssl/safestack.h>
17
18        STACK_OF(TYPE)
19        DEFINE_STACK_OF(TYPE)
20        DEFINE_STACK_OF_CONST(TYPE)
21        DEFINE_SPECIAL_STACK_OF(FUNCTYPE, TYPE)
22        DEFINE_SPECIAL_STACK_OF_CONST(FUNCTYPE, TYPE)
23
24        typedef int (*sk_TYPE_compfunc)(const TYPE *const *a, const TYPE *const *b);
25        typedef TYPE * (*sk_TYPE_copyfunc)(const TYPE *a);
26        typedef void (*sk_TYPE_freefunc)(TYPE *a);
27
28        int sk_TYPE_num(const STACK_OF(TYPE) *sk);
29        TYPE *sk_TYPE_value(const STACK_OF(TYPE) *sk, int idx);
30        STACK_OF(TYPE) *sk_TYPE_new(sk_TYPE_compfunc compare);
31        STACK_OF(TYPE) *sk_TYPE_new_null(void);
32        int sk_TYPE_reserve(STACK_OF(TYPE) *sk, int n);
33        void sk_TYPE_free(const STACK_OF(TYPE) *sk);
34        void sk_TYPE_zero(const STACK_OF(TYPE) *sk);
35        TYPE *sk_TYPE_delete(STACK_OF(TYPE) *sk, int i);
36        TYPE *sk_TYPE_delete_ptr(STACK_OF(TYPE) *sk, TYPE *ptr);
37        int sk_TYPE_push(STACK_OF(TYPE) *sk, const TYPE *ptr);
38        int sk_TYPE_unshift(STACK_OF(TYPE) *sk, const TYPE *ptr);
39        TYPE *sk_TYPE_pop(STACK_OF(TYPE) *sk);
40        TYPE *sk_TYPE_shift(STACK_OF(TYPE) *sk);
41        void sk_TYPE_pop_free(STACK_OF(TYPE) *sk, sk_TYPE_freefunc freefunc);
42        int sk_TYPE_insert(STACK_OF(TYPE) *sk, TYPE *ptr, int idx);
43        TYPE *sk_TYPE_set(STACK_OF(TYPE) *sk, int idx, const TYPE *ptr);
44        int sk_TYPE_find(STACK_OF(TYPE) *sk, TYPE *ptr);
45        int sk_TYPE_find_ex(STACK_OF(TYPE) *sk, TYPE *ptr);
46        void sk_TYPE_sort(const STACK_OF(TYPE) *sk);
47        int sk_TYPE_is_sorted(const STACK_OF(TYPE) *sk);
48        STACK_OF(TYPE) *sk_TYPE_dup(const STACK_OF(TYPE) *sk);
49        STACK_OF(TYPE) *sk_TYPE_deep_copy(const STACK_OF(TYPE) *sk,
50                                          sk_TYPE_copyfunc copyfunc,
51                                          sk_TYPE_freefunc freefunc);
52        sk_TYPE_compfunc (*sk_TYPE_set_cmp_func(STACK_OF(TYPE) *sk,
53                                                sk_TYPE_compfunc compare));
54        STACK_OF(TYPE) *sk_TYPE_new_reserve(sk_TYPE_compfunc compare, int n);
55

DESCRIPTION

57       Applications can create and use their own stacks by placing any of the
58       macros described below in a header file. These macros define typesafe
59       inline functions that wrap around the utility OPENSSL_sk_ API.  In the
60       description here, TYPE is used as a placeholder for any of the OpenSSL
61       datatypes, such as X509.
62
63       STACK_OF() returns the name for a stack of the specified TYPE.
64       DEFINE_STACK_OF() creates set of functions for a stack of TYPE. This
65       will mean that type TYPE is stored in each stack, the type is
66       referenced by STACK_OF(TYPE) and each function name begins with
67       sk_TYPE_. For example:
68
69        TYPE *sk_TYPE_value(STACK_OF(TYPE) *sk, int idx);
70
71       DEFINE_STACK_OF_CONST() is identical to DEFINE_STACK_OF() except each
72       element is constant. For example:
73
74        const TYPE *sk_TYPE_value(STACK_OF(TYPE) *sk, int idx);
75
76       DEFINE_SPECIAL_STACK_OF() defines a stack of TYPE but each function
77       uses FUNCNAME in the function name. For example:
78
79        TYPE *sk_FUNCNAME_value(STACK_OF(TYPE) *sk, int idx);
80
81       DEFINE_SPECIAL_STACK_OF_CONST() is similar except that each element is
82       constant:
83
84        const TYPE *sk_FUNCNAME_value(STACK_OF(TYPE) *sk, int idx);
85
86       sk_TYPE_num() returns the number of elements in sk or -1 if sk is NULL.
87
88       sk_TYPE_value() returns element idx in sk, where idx starts at zero. If
89       idx is out of range then NULL is returned.
90
91       sk_TYPE_new() allocates a new empty stack using comparison function
92       compare.  If compare is NULL then no comparison function is used. This
93       function is equivalent to sk_TYPE_new_reserve(compare, 0).
94
95       sk_TYPE_new_null() allocates a new empty stack with no comparison
96       function. This function is equivalent to sk_TYPE_new_reserve(NULL, 0).
97
98       sk_TYPE_reserve() allocates additional memory in the sk structure such
99       that the next n calls to sk_TYPE_insert(), sk_TYPE_push() or
100       sk_TYPE_unshift() will not fail or cause memory to be allocated or
101       reallocated. If n is zero, any excess space allocated in the sk
102       structure is freed. On error sk is unchanged.
103
104       sk_TYPE_new_reserve() allocates a new stack. The new stack will have
105       additional memory allocated to hold n elements if n is positive. The
106       next n calls to sk_TYPE_insert(), sk_TYPE_push() or sk_TYPE_unshift()
107       will not fail or cause memory to be allocated or reallocated. If n is
108       zero or less than zero, no memory is allocated. sk_TYPE_new_reserve()
109       also sets the comparison function compare to the newly created stack.
110       If compare is NULL then no comparison function is used.
111
112       sk_TYPE_set_cmp_func() sets the comparison function of sk to compare.
113       The previous comparison function is returned or NULL if there was no
114       previous comparison function.
115
116       sk_TYPE_free() frees up the sk structure. It does not free up any
117       elements of sk. After this call sk is no longer valid.
118
119       sk_TYPE_zero() sets the number of elements in sk to zero. It does not
120       free sk so after this call sk is still valid.
121
122       sk_TYPE_pop_free() frees up all elements of sk and sk itself. The free
123       function freefunc() is called on each element to free it.
124
125       sk_TYPE_delete() deletes element i from sk. It returns the deleted
126       element or NULL if i is out of range.
127
128       sk_TYPE_delete_ptr() deletes element matching ptr from sk. It returns
129       the deleted element or NULL if no element matching ptr was found.
130
131       sk_TYPE_insert() inserts ptr into sk at position idx. Any existing
132       elements at or after idx are moved downwards. If idx is out of range
133       the new element is appended to sk. sk_TYPE_insert() either returns the
134       number of elements in sk after the new element is inserted or zero if
135       an error (such as memory allocation failure) occurred.
136
137       sk_TYPE_push() appends ptr to sk it is equivalent to:
138
139        sk_TYPE_insert(sk, ptr, -1);
140
141       sk_TYPE_unshift() inserts ptr at the start of sk it is equivalent to:
142
143        sk_TYPE_insert(sk, ptr, 0);
144
145       sk_TYPE_pop() returns and removes the last element from sk.
146
147       sk_TYPE_shift() returns and removes the first element from sk.
148
149       sk_TYPE_set() sets element idx of sk to ptr replacing the current
150       element. The new element value is returned or NULL if an error
151       occurred: this will only happen if sk is NULL or idx is out of range.
152
153       sk_TYPE_find() searches sk for the element ptr.  In the case where no
154       comparison function has been specified, the function performs a linear
155       search for a pointer equal to ptr. The index of the first matching
156       element is returned or -1 if there is no match. In the case where a
157       comparison function has been specified, sk is sorted then
158       sk_TYPE_find() returns the index of a matching element or -1 if there
159       is no match. Note that, in this case, the matching element returned is
160       not guaranteed to be the first; the comparison function will usually
161       compare the values pointed to rather than the pointers themselves and
162       the order of elements in sk could change.
163
164       sk_TYPE_find_ex() operates like sk_TYPE_find() except when a comparison
165       function has been specified and no matching element is found. Instead
166       of returning -1, sk_TYPE_find_ex() returns the index of the element
167       either before or after the location where ptr would be if it were
168       present in sk.
169
170       sk_TYPE_sort() sorts sk using the supplied comparison function.
171
172       sk_TYPE_is_sorted() returns 1 if sk is sorted and 0 otherwise.
173
174       sk_TYPE_dup() returns a copy of sk. Note the pointers in the copy are
175       identical to the original.
176
177       sk_TYPE_deep_copy() returns a new stack where each element has been
178       copied.  Copying is performed by the supplied copyfunc() and freeing by
179       freefunc(). The function freefunc() is only called if an error occurs.
180

NOTES

182       Care should be taken when accessing stacks in multi-threaded
183       environments.  Any operation which increases the size of a stack such
184       as sk_TYPE_insert() or sk_push() can "grow" the size of an internal
185       array and cause race conditions if the same stack is accessed in a
186       different thread. Operations such as sk_find() and sk_sort() can also
187       reorder the stack.
188
189       Any comparison function supplied should use a metric suitable for use
190       in a binary search operation. That is it should return zero, a positive
191       or negative value if a is equal to, greater than or less than b
192       respectively.
193
194       Care should be taken when checking the return values of the functions
195       sk_TYPE_find() and sk_TYPE_find_ex(). They return an index to the
196       matching element. In particular 0 indicates a matching first element.
197       A failed search is indicated by a -1 return value.
198
199       STACK_OF(), DEFINE_STACK_OF(), DEFINE_STACK_OF_CONST(), and
200       DEFINE_SPECIAL_STACK_OF() are implemented as macros.
201
202       The underlying utility OPENSSL_sk_ API should not be used directly.  It
203       defines these functions: OPENSSL_sk_deep_copy(), OPENSSL_sk_delete(),
204       OPENSSL_sk_delete_ptr(), OPENSSL_sk_dup(), OPENSSL_sk_find(),
205       OPENSSL_sk_find_ex(), OPENSSL_sk_free(), OPENSSL_sk_insert(),
206       OPENSSL_sk_is_sorted(), OPENSSL_sk_new(), OPENSSL_sk_new_null(),
207       OPENSSL_sk_num(), OPENSSL_sk_pop(), OPENSSL_sk_pop_free(),
208       OPENSSL_sk_push(), OPENSSL_sk_reserve(), OPENSSL_sk_set(),
209       OPENSSL_sk_set_cmp_func(), OPENSSL_sk_shift(), OPENSSL_sk_sort(),
210       OPENSSL_sk_unshift(), OPENSSL_sk_value(), OPENSSL_sk_zero().
211

RETURN VALUES

213       sk_TYPE_num() returns the number of elements in the stack or -1 if the
214       passed stack is NULL.
215
216       sk_TYPE_value() returns a pointer to a stack element or NULL if the
217       index is out of range.
218
219       sk_TYPE_new(), sk_TYPE_new_null() and sk_TYPE_new_reserve() return an
220       empty stack or NULL if an error occurs.
221
222       sk_TYPE_reserve() returns 1 on successful allocation of the required
223       memory or 0 on error.
224
225       sk_TYPE_set_cmp_func() returns the old comparison function or NULL if
226       there was no old comparison function.
227
228       sk_TYPE_free(), sk_TYPE_zero(), sk_TYPE_pop_free() and sk_TYPE_sort()
229       do not return values.
230
231       sk_TYPE_pop(), sk_TYPE_shift(), sk_TYPE_delete() and
232       sk_TYPE_delete_ptr() return a pointer to the deleted element or NULL on
233       error.
234
235       sk_TYPE_insert(), sk_TYPE_push() and sk_TYPE_unshift() return the total
236       number of elements in the stack and 0 if an error occurred.
237
238       sk_TYPE_set() returns a pointer to the replacement element or NULL on
239       error.
240
241       sk_TYPE_find() and sk_TYPE_find_ex() return an index to the found
242       element or -1 on error.
243
244       sk_TYPE_is_sorted() returns 1 if the stack is sorted and 0 if it is
245       not.
246
247       sk_TYPE_dup() and sk_TYPE_deep_copy() return a pointer to the copy of
248       the stack.
249

HISTORY

251       Before OpenSSL 1.1.0, this was implemented via macros and not inline
252       functions and was not a public API.
253
254       sk_TYPE_reserve() and sk_TYPE_new_reserve() were added in OpenSSL
255       1.1.1.
256
258       Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
259
260       Licensed under the OpenSSL license (the "License").  You may not use
261       this file except in compliance with the License.  You can obtain a copy
262       in the file LICENSE in the source distribution or at
263       <https://www.openssl.org/source/license.html>.
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2671.1.1k                            2021-03-26                DEFINE_STACK_OF(3)
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