xref: /openssl/doc/man3/ASN1_STRING_length.pod (revision 8c1cbc72) 
1=pod
2
3=head1 NAME
4
5ASN1_STRING_dup, ASN1_STRING_cmp, ASN1_STRING_set, ASN1_STRING_length,
6ASN1_STRING_type, ASN1_STRING_get0_data, ASN1_STRING_data,
7ASN1_STRING_to_UTF8 - ASN1_STRING utility functions
8
9=head1 SYNOPSIS
10
11 #include <openssl/asn1.h>
12
13 int ASN1_STRING_length(ASN1_STRING *x);
14 const unsigned char *ASN1_STRING_get0_data(const ASN1_STRING *x);
15 unsigned char *ASN1_STRING_data(ASN1_STRING *x);
16
17 ASN1_STRING *ASN1_STRING_dup(const ASN1_STRING *a);
18
19 int ASN1_STRING_cmp(ASN1_STRING *a, ASN1_STRING *b);
20
21 int ASN1_STRING_set(ASN1_STRING *str, const void *data, int len);
22
23 int ASN1_STRING_type(const ASN1_STRING *x);
24
25 int ASN1_STRING_to_UTF8(unsigned char **out, const ASN1_STRING *in);
26
27=head1 DESCRIPTION
28
29These functions allow an B<ASN1_STRING> structure to be manipulated.
30
31ASN1_STRING_length() returns the length of the content of I<x>.
32
33ASN1_STRING_get0_data() returns an internal pointer to the data of I<x>.
34Since this is an internal pointer it should B<not> be freed or
35modified in any way.
36
37ASN1_STRING_data() is similar to ASN1_STRING_get0_data() except the
38returned value is not constant. This function is deprecated:
39applications should use ASN1_STRING_get0_data() instead.
40
41ASN1_STRING_dup() returns a copy of the structure I<a>.
42
43ASN1_STRING_cmp() compares I<a> and I<b> returning 0 if the two
44are identical. The string types and content are compared.
45
46ASN1_STRING_set() sets the data of string I<str> to the buffer
47I<data> or length I<len>. The supplied data is copied. If I<len>
48is -1 then the length is determined by strlen(data).
49
50ASN1_STRING_type() returns the type of I<x>, using standard constants
51such as B<V_ASN1_OCTET_STRING>.
52
53ASN1_STRING_to_UTF8() converts the string I<in> to UTF8 format, the
54converted data is allocated in a buffer in I<*out>. The length of
55I<out> is returned or a negative error code. The buffer I<*out>
56should be freed using OPENSSL_free().
57
58=head1 NOTES
59
60Almost all ASN1 types in OpenSSL are represented as an B<ASN1_STRING>
61structure. Other types such as B<ASN1_OCTET_STRING> are simply typedef'ed
62to B<ASN1_STRING> and the functions call the B<ASN1_STRING> equivalents.
63B<ASN1_STRING> is also used for some B<CHOICE> types which consist
64entirely of primitive string types such as B<DirectoryString> and
65B<Time>.
66
67These functions should B<not> be used to examine or modify B<ASN1_INTEGER>
68or B<ASN1_ENUMERATED> types: the relevant B<INTEGER> or B<ENUMERATED>
69utility functions should be used instead.
70
71In general it cannot be assumed that the data returned by ASN1_STRING_data()
72is null terminated or does not contain embedded nulls. The actual format
73of the data will depend on the actual string type itself: for example
74for an IA5String the data will be ASCII, for a BMPString two bytes per
75character in big endian format, and for a UTF8String it will be in UTF8 format.
76
77Similar care should be take to ensure the data is in the correct format
78when calling ASN1_STRING_set().
79
80=head1 RETURN VALUES
81
82ASN1_STRING_length() returns the length of the content of I<x>.
83
84ASN1_STRING_get0_data() and ASN1_STRING_data() return an internal pointer to
85the data of I<x>.
86
87ASN1_STRING_dup() returns a valid B<ASN1_STRING> structure or NULL if an
88error occurred.
89
90ASN1_STRING_cmp() returns an integer greater than, equal to, or less than 0,
91according to whether I<a> is greater than, equal to, or less than I<b>.
92
93ASN1_STRING_set() returns 1 on success or 0 on error.
94
95ASN1_STRING_type() returns the type of I<x>.
96
97ASN1_STRING_to_UTF8() returns the number of bytes in output string I<out> or a
98negative value if an error occurred.
99
100=head1 SEE ALSO
101
102L<ERR_get_error(3)>
103
104=head1 COPYRIGHT
105
106Copyright 2002-2020 The OpenSSL Project Authors. All Rights Reserved.
107
108Licensed under the Apache License 2.0 (the "License").  You may not use
109this file except in compliance with the License.  You can obtain a copy
110in the file LICENSE in the source distribution or at
111L<https://www.openssl.org/source/license.html>.
112
113=cut
114