openssl/doc/internal/man3/DEFINE_SPARSE_ARRAY_OF.pod
Pauli 8ab53b193a Make the sparse array code use ossl_uintmax_t as its index rather than size_t.
This should never reduce the range covered and might increase it on some
platforms.

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8415)
2019-03-06 13:50:54 +10:00

124 lines
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=pod
=head1 NAME
DEFINE_SPARSE_ARRAY_OF, ossl_sa_TYPE_new, ossl_sa_TYPE_free,
ossl_sa_TYPE_free_leaves, ossl_sa_TYPE_num, ossl_sa_TYPE_doall,
ossl_sa_TYPE_doall_arg, ossl_sa_TYPE_get, ossl_sa_TYPE_set
- sparse array container
=head1 SYNOPSIS
=for comment generic
#include "internal/sparse_array.h"
typedef struct sparse_array_st OPENSSL_SA;
SPARSE_ARRAY_OF(TYPE)
DEFINE_SPARSE_ARRAY_OF(TYPE)
SPARSE_ARRAY_OF(TYPE) *ossl_sa_TYPE_new(void);
void ossl_sa_TYPE_free(const SPARSE_ARRAY_OF(TYPE) *sa);
void ossl_sa_TYPE_free_leaves(const SPARSE_ARRAY_OF(TYPE) *sa);
size_t ossl_sa_TYPE_num(const SPARSE_ARRAY_OF(TYPE) *sa);
void ossl_sa_TYPE_doall(const OPENSSL_SA *sa, void (*leaf)(ossl_uintmax_t,
void *));
void ossl_sa_TYPE_doall_arg(const OPENSSL_SA *sa,
void (*leaf)(ossl_uintmax_t, void *, void *),
void *arg);
TYPE *ossl_sa_TYPE_get(const SPARSE_ARRAY_OF(TYPE) *sa, ossl_uintmax_t idx);
int ossl_sa_TYPE_set(SPARSE_ARRAY_OF(TYPE) *sa, ossl_uintmax_t idx,
TYPE *value);
=head1 DESCRIPTION
SPARSE_ARRAY_OF() returns the name for a sparse array of the specified
B<TYPE>. DEFINE_STACK_OF() creates set of functions for a sparse array of
B<TYPE>. This will mean that a pointer to type B<TYPE> is stored in each
element of a sparse array, the type is referenced by SPARSE_ARRAY_OF(TYPE) and
each function name begins with I<ossl_sa_TYPE_>. For example:
TYPE *ossl_sa_TYPE_get(SPARSE_ARRAY_OF(TYPE) *sa, ossl_uintmax_t idx);
ossl_sa_TYPE_num() returns the number of elements in B<sa> or 0 if B<sa> is
B<NULL>.
ossl_sa_TYPE_get() returns element B<idx> in B<sa>, where B<idx> starts at
zero. If B<idx> refers to a value that has not been set then B<NULL> is
returned.
ossl_sa_TYPE_set() sets element B<idx> in B<sa> to B<value>, where B<idx>
starts at zero. The sparse array will be resized as required.
ossl_sa_TYPE_new() allocates a new empty sparse array.
ossl_sa_TYPE_free() frees up the B<sa> structure. It does B<not> free up any
elements of B<sa>. After this call B<sa> is no longer valid.
ossl_sa_TYPE_free_leaves() frees up the B<sa> structure and all of its
elements. After this call B<sa> is no longer valid.
ossl_sa_TYPE_doall() calls the function B<leaf> for each element in B<sa>
in ascending index order. The index position, within the sparse array,
of each item is passed as the first argument to the leaf function and a
pointer to the associated value is is passed as the second argument.
ossl_sa_TYPE_doall_arg() calls the function B<leaf> for each element in
B<sa> in ascending index order. The index position, within the sparse
array, of each item is passed as the first argument to the leaf function,
a pointer to the associated value is passed as the second argument and
the third argument is the user supplied B<arg>.
=head1 NOTES
Sparse arrays are an internal data structure and should B<not> be used by user
applications.
Care should be taken when accessing sparse arrays in multi-threaded
environments. The ossl_sa_TYPE_set operation can cause the internal structure
of the sparse array to change which causes race conditions if the sparse array
is accessed in a different thread.
SPARSE_ARRAY_OF() and DEFINE_SPARSE_ARRAY_OF() are implemented as macros.
The underlying utility B<OPENSSL_SA_> API should not be used directly. It
defines these functions: OPENSSL_SA_doall, OPENSSL_SA_doall_arg,
OPENSSL_SA_free, OPENSSL_SA_free_leaves, OPENSSL_SA_get, OPENSSL_SA_new,
OPENSSL_SA_num and OPENSSL_SA_set.
=head1 RETURN VALUES
ossl_sa_TYPE_num() returns the number of elements in the sparse array or B<0>
if the passed sparse array is B<NULL>.
ossl_sa_TYPE_get() returns a pointer to a sparse array element or B<NULL> if
the element has not be set.
ossl_sa_TYPE_set() return B<1> on success and B<0> on error. In the latter
case, the elements of the sparse array remain unchanged, although the internal
structures might have.
ossl_sa_TYPE_new() returns an empty sparse array or B<NULL> if an error
occurs.
ossl_sa_TYPE_doall, ossl_sa_TYPE_doall_arg, ossl_sa_TYPE_free() and
ossl_sa_TYPE_free_leaves() do not return values.
=head1 HISTORY
This functionality was added to OpenSSL 3.0.0.
=head1 COPYRIGHT
Copyright 2019 The OpenSSL Project Authors. All Rights Reserved. Copyright
(c) 2019, Oracle and/or its affiliates. All rights reserved.
Licensed under the Apache License 2.0 (the "License"). You may not use this
file except in compliance with the License. You can obtain a copy in the file
LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.
=cut