xref: /openssl/doc/internal/man3/OPENSSL_SA.pod (revision 0789c7d8) 
1=pod
2
3=head1 NAME
4
5OPENSSL_SA, ossl_sa_TYPE_new, ossl_sa_TYPE_free,
6ossl_sa_TYPE_free_leaves, ossl_sa_TYPE_num, ossl_sa_TYPE_doall,
7ossl_sa_TYPE_doall_arg, ossl_sa_TYPE_get, ossl_sa_TYPE_set
8- sparse array container
9
10=head1 SYNOPSIS
11
12 #include "crypto/sparse_array.h"
13
14 typedef struct sparse_array_st OPENSSL_SA;
15
16 SPARSE_ARRAY_OF(TYPE)
17 DEFINE_SPARSE_ARRAY_OF(TYPE)
18
19 SPARSE_ARRAY_OF(TYPE) *ossl_sa_TYPE_new(void);
20 void ossl_sa_TYPE_free(const SPARSE_ARRAY_OF(TYPE) *sa);
21 void ossl_sa_TYPE_free_leaves(const SPARSE_ARRAY_OF(TYPE) *sa);
22 size_t ossl_sa_TYPE_num(const SPARSE_ARRAY_OF(TYPE) *sa);
23 void ossl_sa_TYPE_doall(const OPENSSL_SA *sa, void (*leaf)(ossl_uintmax_t,
24                                                            void *));
25 void ossl_sa_TYPE_doall_arg(const OPENSSL_SA *sa,
26                             void (*leaf)(ossl_uintmax_t, void *, void *),
27                             void *arg);
28 TYPE *ossl_sa_TYPE_get(const SPARSE_ARRAY_OF(TYPE) *sa, ossl_uintmax_t idx);
29 int ossl_sa_TYPE_set(SPARSE_ARRAY_OF(TYPE) *sa, ossl_uintmax_t idx,
30                      TYPE *value);
31
32=head1 DESCRIPTION
33
34=begin comment
35
36POD is pretty good at recognising function names and making them appropriately
37bold...  however, when part of the function name is variable, we have to help
38the processor along
39
40=end comment
41
42SPARSE_ARRAY_OF() returns the name for a sparse array of the specified
43B<I<TYPE>>.  DEFINE_SPARSE_ARRAY_OF() creates set of functions for a sparse
44array of B<I<TYPE>>. This will mean that a pointer to type B<I<TYPE>>
45is stored in each element of a sparse array, the type is referenced by
46B<SPARSE_ARRAY_OF>(B<I<TYPE>>) and each function name begins with
47B<ossl_sa_I<TYPE>_>. For example:
48
49 TYPE *ossl_sa_TYPE_get(SPARSE_ARRAY_OF(TYPE) *sa, ossl_uintmax_t idx);
50
51B<ossl_sa_I<TYPE>_num>() returns the number of elements in I<sa> or 0 if I<sa>
52is NULL.
53
54B<ossl_sa_I<TYPE>_get>() returns element I<idx> in I<sa>, where I<idx> starts
55at zero. If I<idx> refers to a value that has not been set then NULL is
56returned.
57
58B<ossl_sa_I<TYPE>_set>() sets element I<idx> in I<sa> to I<value>, where I<idx>
59starts at zero. The sparse array will be resized as required.
60
61B<ossl_sa_I<TYPE>_new>() allocates a new empty sparse array.
62
63B<ossl_sa_I<TYPE>_free>() frees up the I<sa> structure. It does I<not> free up any
64elements of I<sa>. After this call I<sa> is no longer valid.
65
66B<ossl_sa_I<TYPE>_free_leaves>() frees up the I<sa> structure and all of its
67elements.  After this call I<sa> is no longer valid.
68
69B<ossl_sa_I<TYPE>_doall>() calls the function I<leaf> for each element in I<sa>
70in ascending index order. The index position, within the sparse array,
71of each item is passed as the first argument to the leaf function and a
72pointer to the associated value is passed as the second argument.
73
74B<ossl_sa_I<TYPE>_doall_arg>() calls the function I<leaf> for each element in
75I<sa> in ascending index order. The index position, within the sparse
76array, of each item is passed as the first argument to the leaf function,
77a pointer to the associated value is passed as the second argument and
78the third argument is the user supplied I<arg>.
79
80
81=head1 NOTES
82
83Sparse arrays are an internal data structure and should B<not> be used by user
84applications.
85
86Care should be taken when accessing sparse arrays in multi-threaded
87environments.  The B<ossl_sa_I<TYPE>_set>() operation can cause the internal
88structure of the sparse array to change which causes race conditions if the
89sparse array is accessed in a different thread.
90
91SPARSE_ARRAY_OF() and DEFINE_SPARSE_ARRAY_OF() are implemented as macros.
92
93The underlying utility B<OPENSSL_SA_> API should not be used directly.  It
94defines these functions: OPENSSL_SA_doall, OPENSSL_SA_doall_arg,
95OPENSSL_SA_free, OPENSSL_SA_free_leaves, OPENSSL_SA_get, OPENSSL_SA_new,
96OPENSSL_SA_num and OPENSSL_SA_set.
97
98=head1 RETURN VALUES
99
100B<ossl_sa_I<TYPE>_num>() returns the number of elements in the sparse array or
101B<0> if the passed sparse array is NULL.
102
103B<ossl_sa_I<TYPE>_get>() returns a pointer to a sparse array element or NULL if
104the element has not be set.
105
106B<ossl_sa_I<TYPE>_set>() return B<1> on success and B<0> on error. In the latter
107case, the elements of the sparse array remain unchanged, although the internal
108structures might have.
109
110B<ossl_sa_I<TYPE>_new>() returns an empty sparse array or NULL if an error
111occurs.
112
113B<ossl_sa_I<TYPE>_doall>(), B<ossl_sa_I<TYPE>_doall_arg>(),
114B<ossl_sa_I<TYPE>_free>() and B<ossl_sa_I<TYPE>_free_leaves>()
115do not return values.
116
117=head1 HISTORY
118
119This functionality was added to OpenSSL 3.0.
120
121=head1 COPYRIGHT
122
123Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.  Copyright
124(c) 2019, Oracle and/or its affiliates.  All rights reserved.
125
126Licensed under the Apache License 2.0 (the "License").  You may not use this
127file except in compliance with the License.  You can obtain a copy in the file
128LICENSE in the source distribution or at
129L<https://www.openssl.org/source/license.html>.
130
131=cut
132