ASN1_STRING_length.pod revision 331638 
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, ASN1_STRING_to_UTF8 -
7ASN1_STRING utility functions
8
9=head1 SYNOPSIS
10
11 #include <openssl/asn1.h>
12
13 int ASN1_STRING_length(ASN1_STRING *x);
14 unsigned char * ASN1_STRING_data(ASN1_STRING *x);
15
16 ASN1_STRING * ASN1_STRING_dup(ASN1_STRING *a);
17
18 int ASN1_STRING_cmp(ASN1_STRING *a, ASN1_STRING *b);
19
20 int ASN1_STRING_set(ASN1_STRING *str, const void *data, int len);
21
22 int ASN1_STRING_type(ASN1_STRING *x);
23
24 int ASN1_STRING_to_UTF8(unsigned char **out, ASN1_STRING *in);
25
26=head1 DESCRIPTION
27
28These functions allow an B<ASN1_STRING> structure to be manipulated.
29
30ASN1_STRING_length() returns the length of the content of B<x>.
31
32ASN1_STRING_data() returns an internal pointer to the data of B<x>.
33Since this is an internal pointer it should B<not> be freed or
34modified in any way.
35
36ASN1_STRING_dup() returns a copy of the structure B<a>.
37
38ASN1_STRING_cmp() compares B<a> and B<b> returning 0 if the two
39are identical. The string types and content are compared.
40
41ASN1_STRING_set() sets the data of string B<str> to the buffer
42B<data> or length B<len>. The supplied data is copied. If B<len>
43is -1 then the length is determined by strlen(data).
44
45ASN1_STRING_type() returns the type of B<x>, using standard constants
46such as B<V_ASN1_OCTET_STRING>.
47
48ASN1_STRING_to_UTF8() converts the string B<in> to UTF8 format, the
49converted data is allocated in a buffer in B<*out>. The length of
50B<out> is returned or a negative error code. The buffer B<*out>
51should be free using OPENSSL_free().
52
53=head1 NOTES
54
55Almost all ASN1 types in OpenSSL are represented as an B<ASN1_STRING>
56structure. Other types such as B<ASN1_OCTET_STRING> are simply typedefed
57to B<ASN1_STRING> and the functions call the B<ASN1_STRING> equivalents.
58B<ASN1_STRING> is also used for some B<CHOICE> types which consist
59entirely of primitive string types such as B<DirectoryString> and
60B<Time>.
61
62These functions should B<not> be used to examine or modify B<ASN1_INTEGER>
63or B<ASN1_ENUMERATED> types: the relevant B<INTEGER> or B<ENUMERATED>
64utility functions should be used instead.
65
66In general it cannot be assumed that the data returned by ASN1_STRING_data()
67is null terminated or does not contain embedded nulls. The actual format
68of the data will depend on the actual string type itself: for example
69for an IA5String the data will be ASCII, for a BMPString two bytes per
70character in big endian format, and for an UTF8String it will be in UTF8 format.
71
72Similar care should be take to ensure the data is in the correct format
73when calling ASN1_STRING_set().
74
75=head1 RETURN VALUES
76
77=head1 SEE ALSO
78
79L<ERR_get_error(3)|ERR_get_error(3)>
80
81=head1 HISTORY
82
83=cut
84