ASN1_STRING_LENGTH(3)

NAME
ASN1_STRING_cmp, ASN1_STRING_data, ASN1_STRING_dup, ASN1_STRING_length, ASN1_STRING_length_set, ASN1_STRING_set, ASN1_STRING_to_UTF8, ASN1_STRING_type - ASN1_STRING utility functions

SYNOPSIS
#include <openssl/asn1.h>
int
ASN1_STRING_cmp(ASN1_STRING *a, ASN1_STRING *b);
unsigned char *
ASN1_STRING_data(ASN1_STRING *x);
ASN1_STRING *
ASN1_STRING_dup(ASN1_STRING *a);
int
ASN1_STRING_length(ASN1_STRING *x);
void
ASN1_STRING_length_set(ASN1_STRING *x, int len);
int
ASN1_STRING_set(ASN1_STRING *str, const void *data, int len);
int
ASN1_STRING_to_UTF8(unsigned char **out, ASN1_STRING *in);
int
ASN1_STRING_type(ASN1_STRING *x);

DESCRIPTION
These functions manipulate ASN1_STRING structures.

ASN1_STRING_cmp() compares a and b and returns 0 if the two are identical. The string types and the content are compared.

ASN1_STRING_data() returns an internal pointer to the data of x. Since this is an internal pointer, it should not be freed or modified in any way.

ASN1_STRING_dup() returns a copy of the structure a.

ASN1_STRING_length() returns the length of the content of x.

ASN1_STRING_length_set() sets the length attribute of x to len. It may put x into an inconsistent internal state.

ASN1_STRING_set() sets the data of the string str to the buffer data of length len. The supplied data is copied. If len is -1 then the length is determined by strlen(data).

ASN1_STRING_to_UTF8() converts the string in to UTF8 format. The converted data is copied into a newly allocated buffer out. The length of out is returned or a negative error code. The buffer out should be freed using free(3).

ASN1_STRING_type() returns the type of x, using standard constants such as V_ASN1_OCTET_STRING.

Almost all ASN.1 types in OpenSSL are represented as ASN1_STRING structures. Other types such as ASN1_OCTET_STRING are simply typedefed to ASN1_STRING and the functions call the ASN1_STRING equivalents. ASN1_STRING is also used for some CHOICE types which consist entirely of primitive string types such as DirectoryString and Time.

These functions should not be used to examine or modify ASN1_INTEGER or ASN1_ENUMERATED types: the relevant INTEGER or ENUMERATED utility functions should be used instead.

In general it cannot be assumed that the data returned by ASN1_STRING_data() is NUL terminated, and it may contain embedded NUL characters. The actual format of the data will depend on the actual string type itself: for example for an IA5String the data will be ASCII, for a BMPString two bytes per character in big endian format, and a UTF8String will be in UTF8 format.

Similar care should be take to ensure the data is in the correct format when calling ASN1_STRING_set().

SEE ALSO
ERR_get_error(3)