doc/internal/man3/DEFINE_SPARSE_ARRAY_OF.pod

   1 =pod
   2
   3 =head1 NAME
   4
   5 DEFINE_SPARSE_ARRAY_OF, ossl_sa_TYPE_new, ossl_sa_TYPE_free,
   6 ossl_sa_TYPE_free_leaves, ossl_sa_TYPE_num, ossl_sa_TYPE_doall,
   7 ossl_sa_TYPE_doall_arg, ossl_sa_TYPE_get, ossl_sa_TYPE_set
   8 - sparse array container
   9
  10 =head1 SYNOPSIS
  11
  12  #include "internal/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  int ossl_sa_TYPE_num(const SPARSE_ARRAY_OF(TYPE) *sa);
  23  void ossl_sa_TYPE_doall(const OPENSSL_SA *sa, void (*leaf)(size_t, void *));
  24  void ossl_sa_TYPE_doall_arg(const OPENSSL_SA *sa,
  25                              void (*leaf)(size_t, void *, void *), void *arg);
  26  TYPE *ossl_sa_TYPE_get(const SPARSE_ARRAY_OF(TYPE) *sa, size_t idx);
  27  int ossl_sa_TYPE_set(SPARSE_ARRAY_OF(TYPE) *sa, size_t idx, TYPE *value);
  28
  29 =head1 DESCRIPTION
  30
  31 SPARSE_ARRAY_OF() returns the name for a sparse array of the specified
  32 B<TYPE>.  DEFINE_STACK_OF() creates set of functions for a sparse array of
  33 B<TYPE>. This will mean that a pointer to type B<TYPE> is stored in each
  34 element of a sparse array, the type is referenced by SPARSE_ARRAY_OF(TYPE) and
  35 each function name begins with I<ossl_sa_TYPE_>. For example:
  36
  37  TYPE *ossl_sa_TYPE_get(SPARSE_ARRAY_OF(TYPE) *sa, size_t idx);
  38
  39 ossl_sa_TYPE_num() returns the number of elements in B<sa> or 0 if B<sa> is
  40 B<NULL>.
  41
  42 ossl_sa_TYPE_get() returns element B<idx> in B<sa>, where B<idx> starts at
  43 zero. If B<idx> refers to a value that has not been set then B<NULL> is
  44 returned.
  45
  46 ossl_sa_TYPE_set() sets element B<idx> in B<sa> to B<value>, where B<idx>
  47 starts at zero. The sparse array will be resized as required.
  48
  49 ossl_sa_TYPE_new() allocates a new empty sparse array.
  50
  51 ossl_sa_TYPE_free() frees up the B<sa> structure. It does B<not> free up any
  52 elements of B<sa>. After this call B<sa> is no longer valid.
  53
  54 ossl_sa_TYPE_free_leaves() frees up the B<sa> structure and all of its
  55 elements.  After this call B<sa> is no longer valid.
  56
  57 ossl_sa_TYPE_doall() calls the function B<leaf> for each element in B<sa>
  58 in ascending index order. The index position, within the sparse array,
  59 of each item is passed as the first argument to the leaf function and a
  60 pointer to the associated value is is passed as the second argument.
  61
  62 ossl_sa_TYPE_doall_arg() calls the function B<leaf> for each element in
  63 B<sa> in ascending index order. The index position, within the sparse
  64 array, of each item is passed as the first argument to the leaf function,
  65 a pointer to the associated value is passed as the second argument and
  66 the third argument is the user supplied B<arg>.
  67
  68
  69 =head1 NOTES
  70
  71 Sparse arrays are an internal data structure and should B<not> be used by user
  72 applications.
  73
  74 Care should be taken when accessing sparse arrays in multi-threaded
  75 environments.  The ossl_sa_TYPE_set operation can cause the internal structure
  76 of the sparse array to change which causes race conditions if the sparse array
  77 is accessed in a different thread.
  78
  79 SPARSE_ARRAY_OF() and DEFINE_SPARSE_ARRAY_OF() are implemented as macros.
  80
  81 The underlying utility B<OPENSSL_SA_> API should not be used directly.  It
  82 defines these functions: OPENSSL_SA_doall, OPENSSL_SA_doall_arg,
  83 OPENSSL_SA_free, OPENSSL_SA_free_leaves, OPENSSL_SA_get, OPENSSL_SA_new,
  84 OPENSSL_SA_num and OPENSSL_SA_set.
  85
  86 =head1 RETURN VALUES
  87
  88 ossl_sa_TYPE_num() returns the number of elements in the sparse array or B<0>
  89 if the passed sparse array is B<NULL>.
  90
  91 ossl_sa_TYPE_get() returns a pointer to a sparse array element or B<NULL> if
  92 the element has not be set.
  93
  94 ossl_sa_TYPE_set() return B<1> on success and B<0> on error. In the latter
  95 case, the elements of the sparse array remain unchanged, although the internal
  96 structures might have.
  97
  98 ossl_sa_TYPE_new() returns an empty sparse array or B<NULL> if an error
  99 occurs.
 100
 101 ossl_sa_TYPE_doall, ossl_sa_TYPE_doall_arg, ossl_sa_TYPE_free() and
 102 ossl_sa_TYPE_free_leaves() do not return values.
 103
 104 =head1 HISTORY
 105
 106 This functionality was added to OpenSSL 3.0.0.
 107
 108 =head1 COPYRIGHT
 109
 110 Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.  Copyright
 111 (c) 2019, Oracle and/or its affiliates.  All rights reserved.
 112
 113 Licensed under the Apache License 2.0 (the "License").  You may not use this
 114 file except in compliance with the License.  You can obtain a copy in the file
 115 LICENSE in the source distribution or at
 116 L<https://www.openssl.org/source/license.html>.
 117
 118 =cut