u8_validate(3C) Standard C Library Functions u8_validate(3C)NAMEu8_validate - validate UTF-8 characters and calculate the byte length
SYNOPSIS
#include <sys/u8_textprep.h>
int u8_validate(char *u8str, size_t n, char **list, int flag,
int *errnum);
PARAMETERS
u8str The UTF-8 string to be validated.
n The maximum number of bytes in u8str that can be examined and
validated.
list A list of null-terminated character strings in UTF-8 that
must be additionally checked against as invalid characters.
The last string in list must be null to indicate there is no
further string.
flag Possible validation options constructed by a bitwise-inclu‐
sive-OR of the following values:
U8_VALIDATE_ENTIRE
By default, u8_validate() looks at the first character or
up to n bytes, whichever is smaller in terms of the num‐
ber of bytes to be consumed, and returns with the result.
When this option is used, u8_validate() will check up to
n bytes from u8str and possibly more than a character
before returning the result.
U8_VALIDATE_CHECK_ADDITIONAL
By default, u8_validate() does not use list supplied.
When this option is supplied with a list of character
strings, u8_validate() additionally validates u8str
against the character strings supplied with list and
returns EBADF in errnum if u8str has any one of the char‐
acter strings in list.
U8_VALIDATE_UCS2_RANGE
By default, u8_validate() uses the entire Unicode coding
space of U+0000 to U+10FFFF.
When this option is specified, the valid Unicode coding
space is smaller to U+0000 to U+FFFF.
errnum An error occurred during validation. The following values
are supported:
EBADF Validation failed because list-specified characters
were found in the string pointed to by u8str.
EILSEQ Validation failed because an illegal byte was found
in the string pointed to by u8str.
EINVAL Validation failed because an incomplete byte was
found in the string pointed to by u8str.
ERANGE Validation failed because character bytes were
encountered that are outside the range of the Uni‐
code coding space.
DESCRIPTION
The u8_validate() function validates u8str in UTF-8 and determines the
number of bytes constituting the character(s) pointed to by u8str.
RETURN VALUES
If u8str is a null pointer, u8_validate() returns 0. Otherwise, u8_val‐
idate() returns either the number of bytes that constitute the charac‐
ters if the next n or fewer bytes form valid characters, or -1 if there
is an validation failure, in which case it may set errnum to indicate
the error.
EXAMPLES
Example 1 Determine the length of the first UTF-8 character.
#include <sys/u8_textprep.h>
char u8[MAXPATHLEN];
int errnum;
.
.
.
len = u8_validate(u8, 4, (char **)NULL, 0, &errnum);
if (len == -1) {
switch (errnum) {
case EILSEQ:
case EINVAL:
return (MYFS4_ERR_INVAL);
case EBADF:
return (MYFS4_ERR_BADNAME);
case ERANGE:
return (MYFS4_ERR_BADCHAR);
default:
return (-10);
}
}
Example 2 Check if there are any invalid characters in the entire
string.
#include <sys/u8_textprep.h>
char u8[MAXPATHLEN];
int n;
int errnum;
.
.
.
n = strlen(u8);
len = u8_validate(u8, n, (char **)NULL, U8_VALIDATE_ENTIRE, &errnum);
if (len == -1) {
switch (errnum) {
case EILSEQ:
case EINVAL:
return (MYFS4_ERR_INVAL);
case EBADF:
return (MYFS4_ERR_BADNAME);
case ERANGE:
return (MYFS4_ERR_BADCHAR);
default:
return (-10);
}
}
Example 3 Check if there is any invalid character, including prohibited
characters, in the entire string.
#include <sys/u8_textprep.h>
char u8[MAXPATHLEN];
int n;
int errnum;
char *prohibited[4] = {
".", "..", "\\", NULL
};
.
.
.
n = strlen(u8);
len = u8_validate(u8, n, prohibited,
(U8_VALIDATE_ENTIRE|U8_VALIDATE_CHECK_ADDITIONAL), &errnum);
if (len == -1) {
switch (errnum) {
case EILSEQ:
case EINVAL:
return (MYFS4_ERR_INVAL);
case EBADF:
return (MYFS4_ERR_BADNAME);
case ERANGE:
return (MYFS4_ERR_BADCHAR);
default:
return (-10);
}
}
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Committed │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOu8_strcmp(3C), u8_textprep_str(3C), attributes(5), u8_strcmp(9F),
u8_textprep_str(9F), u8_validate(9F)
The Unicode Standard (http://www.unicode.org)
SunOS 5.10 18 Sep 2007 u8_validate(3C)
