1=pod
2
3=head1 NAME
4
5ASN1_STRING_dup, ASN1_STRING_cmp, ASN1_STRING_set, ASN1_STRING_length,
6ASN1_STRING_length_set, ASN1_STRING_type, ASN1_STRING_data -
7ASN1_STRING utility functions
8
9=head1 SYNOPSIS
10
11 int ASN1_STRING_length(ASN1_STRING *x);
12 unsigned char * ASN1_STRING_data(ASN1_STRING *x);
13
14 ASN1_STRING * ASN1_STRING_dup(ASN1_STRING *a);
15
16 int ASN1_STRING_cmp(ASN1_STRING *a, ASN1_STRING *b);
17
18 int ASN1_STRING_set(ASN1_STRING *str, const void *data, int len);
19
20 int ASN1_STRING_type(ASN1_STRING *x);
21
22 int ASN1_STRING_to_UTF8(unsigned char **out, ASN1_STRING *in);
23
24=head1 DESCRIPTION
25
26These functions allow an B<ASN1_STRING> structure to be manipulated.
27
28ASN1_STRING_length() returns the length of the content of B<x>.
29
30ASN1_STRING_data() returns an internal pointer to the data of B<x>.
31Since this is an internal pointer it should B<not> be freed or
32modified in any way.
33
34ASN1_STRING_dup() returns a copy of the structure B<a>.
35
36ASN1_STRING_cmp() compares B<a> and B<b> returning 0 if the two
37are identical. The string types and content are compared.
38
39ASN1_STRING_set() sets the data of string B<str> to the buffer
40B<data> or length B<len>. The supplied data is copied. If B<len>
41is -1 then the length is determined by strlen(data).
42
43ASN1_STRING_type() returns the type of B<x>, using standard constants
44such as B<V_ASN1_OCTET_STRING>.
45
46ASN1_STRING_to_UTF8() converts the string B<in> to UTF8 format, the
47converted data is allocated in a buffer in B<*out>. The length of
48B<out> is returned or a negative error code. The buffer B<*out>
49should be free using OPENSSL_free().
50
51=head1 NOTES
52
53Almost all ASN1 types in OpenSSL are represented as an B<ASN1_STRING>
54structure. Other types such as B<ASN1_OCTET_STRING> are simply typedefed
55to B<ASN1_STRING> and the functions call the B<ASN1_STRING> equivalents.
56B<ASN1_STRING> is also used for some B<CHOICE> types which consist
57entirely of primitive string types such as B<DirectoryString> and
58B<Time>.
59
60These functions should B<not> be used to examine or modify B<ASN1_INTEGER>
61or B<ASN1_ENUMERATED> types: the relevant B<INTEGER> or B<ENUMERATED>
62utility functions should be used instead.
63
64In general it cannot be assumed that the data returned by ASN1_STRING_data()
65is null terminated or does not contain embedded nulls. The actual format
66of the data will depend on the actual string type itself: for example
67for and IA5String the data will be ASCII, for a BMPString two bytes per
68character in big endian format, UTF8String will be in UTF8 format.
69
70Similar care should be take to ensure the data is in the correct format
71when calling ASN1_STRING_set().
72
73=head1 RETURN VALUES
74
75=head1 SEE ALSO
76
77L<ERR_get_error(3)|ERR_get_error(3)>
78
79=head1 HISTORY
80
81=cut
82