ASN1_STRING_LENGTH(3)

NAME
ASN1_STRING_cmp, ASN1_OCTET_STRING_cmp, ASN1_STRING_data, ASN1_STRING_dup, ASN1_OCTET_STRING_dup, ASN1_STRING_get0_data, ASN1_STRING_length, ASN1_STRING_length_set, ASN1_STRING_set, ASN1_OCTET_STRING_set, ASN1_STRING_to_UTF8, ASN1_STRING_type - ASN1_STRING utility functions

SYNOPSIS
#include <openssl/asn1.h>
int
ASN1_STRING_cmp(const ASN1_STRING *a, const ASN1_STRING *b);
int
ASN1_OCTET_STRING_cmp(const ASN1_OCTET_STRING *a, const ASN1_OCTET_STRING *b);
unsigned char *
ASN1_STRING_data(ASN1_STRING *x);
ASN1_STRING *
ASN1_STRING_dup(const ASN1_STRING *a);
ASN1_OCTET_STRING *
ASN1_OCTET_STRING_dup(const ASN1_OCTET_STRING *a);
const unsigned char *
ASN1_STRING_get0_data(const ASN1_STRING *x);
int
ASN1_STRING_length(const 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_OCTET_STRING_set(ASN1_OCTET_STRING *str, const unsigned char *data, int len);
int
ASN1_STRING_to_UTF8(unsigned char **out, const ASN1_STRING *in);
int
ASN1_STRING_type(const ASN1_STRING *x);

DESCRIPTION
These functions manipulate ASN1_STRING structures.

ASN1_STRING_cmp() and ASN1_OCTET_STRING_cmp() compare the type, the length, and the content of a and b.

ASN1_STRING_data() is similar to ASN1_STRING_get0_data() except that the returned value is not constant. This function is deprecated. Applications should use ASN1_STRING_get0_data() instead.

ASN1_STRING_dup() and ASN1_OCTET_STRING_dup() copy a.

ASN1_STRING_get0_data() returns an internal pointer to the data of x. It should not be freed or modified in any way.

ASN1_STRING_length() returns the length attribute of x, measured in bytes.

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

ASN1_STRING_set() and ASN1_OCTET_STRING_set() set the length attribute of str to len and copy that number of bytes from data into str. If len is -1, then strlen(data) is used instead of len. If data is NULL, the content of str remains uninitialized; that is not considered an error unless len is negative.

ASN1_STRING_to_UTF8() converts the string in to UTF-8 format. The converted data is copied into a newly allocated buffer *out. The buffer *out should be freed using free(3).

ASN1_STRING_type() returns the type of x.

Almost all ASN.1 types 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_get0_data() and ASN1_STRING_data() is NUL terminated, and it may contain embedded NUL characters. The format of the data depends on the string type: for example for an IA5String the data contains ASCII characters, for a BMPString two bytes per character in big endian format, and for a UTF8String UTF-8 characters.

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

RETURN VALUES
ASN1_STRING_cmp() and ASN1_OCTET_STRING_cmp() return 0 if the type, the length, and the content of a and b agree, or a non-zero value otherwise. In contrast to strcmp(3), the sign of the return value does not indicate lexicographical ordering.

ASN1_STRING_data() and ASN1_STRING_get0_data() return an internal pointer to the data of x.

ASN1_STRING_dup() and ASN1_OCTET_STRING_dup() return a pointer to a newly allocated ASN1_STRING structure or NULL if an error occurred.

ASN1_STRING_length() returns a number of bytes.

ASN1_STRING_set() and ASN1_OCTET_STRING_set() return 1 on success or 0 on failure.

ASN1_STRING_to_UTF8() returns the number of bytes in the output buffer *out, or a negative number if an error occurred.

ASN1_STRING_type() returns an integer constant, for example V_ASN1_OCTET_STRING.

In some cases of failure of ASN1_STRING_dup(), ASN1_STRING_set(), and ASN1_STRING_to_UTF8(), the reason can be determined with ERR_get_error(3).

SEE ALSO
ASN1_STRING_new(3)

HISTORY
ASN1_STRING_cmp(), ASN1_STRING_dup(), ASN1_STRING_set(), and ASN1_OCTET_STRING_set() first appeared in SSLeay 0.6.5. ASN1_OCTET_STRING_cmp(), ASN1_STRING_data(), ASN1_OCTET_STRING_dup(), and ASN1_STRING_type() first appeared in SSLeay 0.8.0. ASN1_STRING_length() first appeared in SSLeay 0.9.0. All these functions have been available since OpenBSD 2.4.

ASN1_STRING_length_set() first appeared in OpenSSL 0.9.5 and has been available since OpenBSD 2.7.

ASN1_STRING_to_UTF8() first appeared in OpenSSL 0.9.6 and has been available since OpenBSD 2.9.

ASN1_STRING_get0_data() first appeared in OpenSSL 1.1.0 and has been available since OpenBSD 6.3.