ASN1_STRING_print_ex, ASN1_STRING_print_ex_fp — ASN1_STRING output routines.
ASN1_STRING_print_ex(BIO *out, ASN1_STRING *str, unsigned long flags);
ASN1_STRING_print_ex_fp(FILE *fp, ASN1_STRING *str, unsigned long
int ASN1_STRING_print(BIO *out, ASN1_STRING *str);
These functions output an ASN1_STRING structure. ASN1_STRING is
used to represent all the ASN1 string types.
ASN1_STRING_print_ex() outputs str to out,
the format is determined by the options flags. ASN1_STRING_print_ex_fp()
is identical except it outputs to fp instead.
ASN1_STRING_print() prints str to out but
using a different format to ASN1_STRING_print_ex(). It replaces unprintable
characters (other than CR, LF) with '.'.
ASN1_STRING_print() is a legacy function which should be avoided
in new applications.
Although there are a large number of options frequently ASN1_STRFLAGS_RFC2253 is
suitable, or on UTF8 terminals ASN1_STRFLAGS_RFC2253 & ~ASN1_STRFLAGS_ESC_MSB.
The complete set of supported options for flags is
Various characters can be escaped. If ASN1_STRFLGS_ESC_2253 is
set the characters determined by RFC2253 are escaped. If ASN1_STRFLGS_ESC_CTRL is
set control characters are escaped. If ASN1_STRFLGS_ESC_MSB is
set characters with the MSB set are escaped: this option should not be
used if the terminal correctly interprets UTF8 sequences.
Escaping takes several forms.
If the character being escaped is a 16 bit character then
the form "\WXXXX" is used using exactly four characters
for the hex representation. If it is 32 bits then "\uXXXXXXXX"
is used using eight characters of its hex representation. These
forms will only be used if UTF8 conversion is not set (see below).
Printable characters are normally escaped using the backslash
'\' character. If ASN1_STRFLGS_ESC_QUOTE is
set then the whole string is instead surrounded by double quote characters:
this is arguably more readable than the backslash notation. Other
characters use the "\XX" using exactly two characters of
the hex representation.
If ASN1_STRFLGS_UTF8_CONVERT is set then
characters are converted to UTF8 format first. If the terminal supports
the display of UTF8 sequences then this option will correctly display
multi byte characters.
If ASN1_STRFLGS_IGNORE_TYPE is set then
the string type is not interpreted at all: everything is assumed
to be one byte per character. This is primarily for debugging purposes
and can result in confusing output in multi character strings.
If ASN1_STRFLGS_SHOW_TYPE is set then
the string type itself is printed out before its value (for example "BMPSTRING"),
this actually uses ASN1_tag2str().
The content of a string instead of being interpreted can be
"dumped": this just outputs the value of the string using the form
#XXXX using hex format for each octet.
If ASN1_STRFLGS_DUMP_ALL is set then
any type is dumped.
Normally non character string types (such as OCTET STRING)
are assumed to be one byte per character, if ASN1_STRFLAGS_DUMP_UNKNOWN is
set then they will be dumped instead.
When a type is dumped normally just the content octets are
printed, if ASN1_STRFLGS_DUMP_DER is set then
the complete encoding is dumped instead (including tag and length
ASN1_STRFLGS_RFC2253 includes all the
flags required by RFC2253. It is equivalent to: ASN1_STRFLGS_ESC_2253 | ASN1_STRFLGS_ESC_CTRL | ASN1_STRFLGS_ESC_MSB | ASN1_STRFLGS_UTF8_CONVERT | ASN1_STRFLGS_DUMP_UNKNOWN ASN1_STRFLGS_DUMP_DER