ICU 59.1  59.1
Data Structures | Namespaces | Macros | Typedefs | Enumerations | Functions
uidna.h File Reference

C API: Internationalizing Domain Names in Applications (IDNA) More...

#include "unicode/utypes.h"
#include "unicode/localpointer.h"
#include "unicode/parseerr.h"

Go to the source code of this file.

Data Structures

struct  UIDNAInfo
 Output container for IDNA processing errors. More...
 

Namespaces

 icu
 File coll.h.
 

Macros

#define UIDNA_INFO_INITIALIZER
 Static initializer for a UIDNAInfo struct. More...
 

Typedefs

typedef struct UIDNA UIDNA
 C typedef for struct UIDNA. More...
 
typedef struct UIDNAInfo UIDNAInfo
 Output container for IDNA processing errors. More...
 

Enumerations

enum  {
  UIDNA_DEFAULT =0, UIDNA_ALLOW_UNASSIGNED =1, UIDNA_USE_STD3_RULES =2, UIDNA_CHECK_BIDI =4,
  UIDNA_CHECK_CONTEXTJ =8, UIDNA_NONTRANSITIONAL_TO_ASCII =0x10, UIDNA_NONTRANSITIONAL_TO_UNICODE =0x20, UIDNA_CHECK_CONTEXTO =0x40
}
 
enum  {
  UIDNA_ERROR_EMPTY_LABEL =1, UIDNA_ERROR_LABEL_TOO_LONG =2, UIDNA_ERROR_DOMAIN_NAME_TOO_LONG =4, UIDNA_ERROR_LEADING_HYPHEN =8,
  UIDNA_ERROR_TRAILING_HYPHEN =0x10, UIDNA_ERROR_HYPHEN_3_4 =0x20, UIDNA_ERROR_LEADING_COMBINING_MARK =0x40, UIDNA_ERROR_DISALLOWED =0x80,
  UIDNA_ERROR_PUNYCODE =0x100, UIDNA_ERROR_LABEL_HAS_DOT =0x200, UIDNA_ERROR_INVALID_ACE_LABEL =0x400, UIDNA_ERROR_BIDI =0x800,
  UIDNA_ERROR_CONTEXTJ =0x1000, UIDNA_ERROR_CONTEXTO_PUNCTUATION =0x2000, UIDNA_ERROR_CONTEXTO_DIGITS =0x4000
}
 

Functions

UIDNAuidna_openUTS46 (uint32_t options, UErrorCode *pErrorCode)
 Returns a UIDNA instance which implements UTS #46. More...
 
void uidna_close (UIDNA *idna)
 Closes a UIDNA instance. More...
 
int32_t uidna_labelToASCII (const UIDNA *idna, const UChar *label, int32_t length, UChar *dest, int32_t capacity, UIDNAInfo *pInfo, UErrorCode *pErrorCode)
 Converts a single domain name label into its ASCII form for DNS lookup. More...
 
int32_t uidna_labelToUnicode (const UIDNA *idna, const UChar *label, int32_t length, UChar *dest, int32_t capacity, UIDNAInfo *pInfo, UErrorCode *pErrorCode)
 Converts a single domain name label into its Unicode form for human-readable display. More...
 
int32_t uidna_nameToASCII (const UIDNA *idna, const UChar *name, int32_t length, UChar *dest, int32_t capacity, UIDNAInfo *pInfo, UErrorCode *pErrorCode)
 Converts a whole domain name into its ASCII form for DNS lookup. More...
 
int32_t uidna_nameToUnicode (const UIDNA *idna, const UChar *name, int32_t length, UChar *dest, int32_t capacity, UIDNAInfo *pInfo, UErrorCode *pErrorCode)
 Converts a whole domain name into its Unicode form for human-readable display. More...
 
int32_t uidna_labelToASCII_UTF8 (const UIDNA *idna, const char *label, int32_t length, char *dest, int32_t capacity, UIDNAInfo *pInfo, UErrorCode *pErrorCode)
 Converts a single domain name label into its ASCII form for DNS lookup. More...
 
int32_t uidna_labelToUnicodeUTF8 (const UIDNA *idna, const char *label, int32_t length, char *dest, int32_t capacity, UIDNAInfo *pInfo, UErrorCode *pErrorCode)
 Converts a single domain name label into its Unicode form for human-readable display. More...
 
int32_t uidna_nameToASCII_UTF8 (const UIDNA *idna, const char *name, int32_t length, char *dest, int32_t capacity, UIDNAInfo *pInfo, UErrorCode *pErrorCode)
 Converts a whole domain name into its ASCII form for DNS lookup. More...
 
int32_t uidna_nameToUnicodeUTF8 (const UIDNA *idna, const char *name, int32_t length, char *dest, int32_t capacity, UIDNAInfo *pInfo, UErrorCode *pErrorCode)
 Converts a whole domain name into its Unicode form for human-readable display. More...
 
int32_t uidna_toASCII (const UChar *src, int32_t srcLength, UChar *dest, int32_t destCapacity, int32_t options, UParseError *parseError, UErrorCode *status)
 IDNA2003: This function implements the ToASCII operation as defined in the IDNA RFC. More...
 
int32_t uidna_toUnicode (const UChar *src, int32_t srcLength, UChar *dest, int32_t destCapacity, int32_t options, UParseError *parseError, UErrorCode *status)
 IDNA2003: This function implements the ToUnicode operation as defined in the IDNA RFC. More...
 
int32_t uidna_IDNToASCII (const UChar *src, int32_t srcLength, UChar *dest, int32_t destCapacity, int32_t options, UParseError *parseError, UErrorCode *status)
 IDNA2003: Convenience function that implements the IDNToASCII operation as defined in the IDNA RFC. More...
 
int32_t uidna_IDNToUnicode (const UChar *src, int32_t srcLength, UChar *dest, int32_t destCapacity, int32_t options, UParseError *parseError, UErrorCode *status)
 IDNA2003: Convenience function that implements the IDNToUnicode operation as defined in the IDNA RFC. More...
 
int32_t uidna_compare (const UChar *s1, int32_t length1, const UChar *s2, int32_t length2, int32_t options, UErrorCode *status)
 IDNA2003: Compare two IDN strings for equivalence. More...
 

Detailed Description

C API: Internationalizing Domain Names in Applications (IDNA)

IDNA2008 is implemented according to UTS #46, see the IDNA C++ class in idna.h.

The C API functions which do take a UIDNA * service object pointer implement UTS #46 and IDNA2008.

IDNA2003 is obsolete. The C API functions which do not take a service object pointer implement IDNA2003. They are all deprecated.

Definition in file uidna.h.

Macro Definition Documentation

§ UIDNA_INFO_INITIALIZER

#define UIDNA_INFO_INITIALIZER
Value:
{ \
(int16_t)sizeof(UIDNAInfo), \
FALSE, FALSE, \
0, 0, 0 }
Output container for IDNA processing errors.
Definition: uidna.h:181
#define FALSE
The FALSE value of a UBool.
Definition: umachine.h:244

Static initializer for a UIDNAInfo struct.

Stable:
ICU 4.6

Definition at line 205 of file uidna.h.

Typedef Documentation

§ UIDNA

typedef struct UIDNA UIDNA

C typedef for struct UIDNA.

Stable:
ICU 4.6

Definition at line 122 of file uidna.h.

§ UIDNAInfo

typedef struct UIDNAInfo UIDNAInfo

Output container for IDNA processing errors.

Initialize with UIDNA_INFO_INITIALIZER:

int32_t length = uidna_nameToASCII(..., &info, &errorCode);
if(U_SUCCESS(errorCode) && info.errors!=0) { ... }
Stable:
ICU 4.6

Enumeration Type Documentation

§ anonymous enum

anonymous enum
Enumerator
UIDNA_DEFAULT 

Default options value: None of the other options are set.

For use in static worker and factory methods.

Stable:
ICU 2.6
UIDNA_ALLOW_UNASSIGNED 

Option to allow unassigned code points in domain names and labels.

For use in static worker and factory methods.

This option is ignored by the UTS46 implementation. (UTS #46 disallows unassigned code points.)

Deprecated:
ICU 55 Use UTS #46 instead via uidna_openUTS46() or class IDNA.
UIDNA_USE_STD3_RULES 

Option to check whether the input conforms to the STD3 ASCII rules, for example the restriction of labels to LDH characters (ASCII Letters, Digits and Hyphen-Minus).

For use in static worker and factory methods.

Stable:
ICU 2.6
UIDNA_CHECK_BIDI 

IDNA option to check for whether the input conforms to the BiDi rules.

For use in static worker and factory methods.

This option is ignored by the IDNA2003 implementation. (IDNA2003 always performs a BiDi check.)

Stable:
ICU 4.6
UIDNA_CHECK_CONTEXTJ 

IDNA option to check for whether the input conforms to the CONTEXTJ rules.

For use in static worker and factory methods.

This option is ignored by the IDNA2003 implementation. (The CONTEXTJ check is new in IDNA2008.)

Stable:
ICU 4.6
UIDNA_NONTRANSITIONAL_TO_ASCII 

IDNA option for nontransitional processing in ToASCII().

For use in static worker and factory methods.

By default, ToASCII() uses transitional processing.

This option is ignored by the IDNA2003 implementation. (This is only relevant for compatibility of newer IDNA implementations with IDNA2003.)

Stable:
ICU 4.6
UIDNA_NONTRANSITIONAL_TO_UNICODE 

IDNA option for nontransitional processing in ToUnicode().

For use in static worker and factory methods.

By default, ToUnicode() uses transitional processing.

This option is ignored by the IDNA2003 implementation. (This is only relevant for compatibility of newer IDNA implementations with IDNA2003.)

Stable:
ICU 4.6
UIDNA_CHECK_CONTEXTO 

IDNA option to check for whether the input conforms to the CONTEXTO rules.

For use in static worker and factory methods.

This option is ignored by the IDNA2003 implementation. (The CONTEXTO check is new in IDNA2008.)

This is for use by registries for IDNA2008 conformance. UTS #46 does not require the CONTEXTO check.

Stable:
ICU 49

Definition at line 46 of file uidna.h.

§ anonymous enum

anonymous enum
Enumerator
UIDNA_ERROR_EMPTY_LABEL 

A non-final domain name label (or the whole domain name) is empty.

Stable:
ICU 4.6
UIDNA_ERROR_LABEL_TOO_LONG 

A domain name label is longer than 63 bytes.

(See STD13/RFC1034 3.1. Name space specifications and terminology.) This is only checked in ToASCII operations, and only if the output label is all-ASCII.

Stable:
ICU 4.6
UIDNA_ERROR_DOMAIN_NAME_TOO_LONG 

A domain name is longer than 255 bytes in its storage form.

(See STD13/RFC1034 3.1. Name space specifications and terminology.) This is only checked in ToASCII operations, and only if the output domain name is all-ASCII.

Stable:
ICU 4.6
UIDNA_ERROR_LEADING_HYPHEN 

A label starts with a hyphen-minus ('-').

Stable:
ICU 4.6
UIDNA_ERROR_TRAILING_HYPHEN 

A label ends with a hyphen-minus ('-').

Stable:
ICU 4.6
UIDNA_ERROR_HYPHEN_3_4 

A label contains hyphen-minus ('-') in the third and fourth positions.

Stable:
ICU 4.6
UIDNA_ERROR_LEADING_COMBINING_MARK 

A label starts with a combining mark.

Stable:
ICU 4.6
UIDNA_ERROR_DISALLOWED 

A label or domain name contains disallowed characters.

Stable:
ICU 4.6
UIDNA_ERROR_PUNYCODE 

A label starts with "xn--" but does not contain valid Punycode.

That is, an xn– label failed Punycode decoding.

Stable:
ICU 4.6
UIDNA_ERROR_LABEL_HAS_DOT 

A label contains a dot=full stop.

This can occur in an input string for a single-label function.

Stable:
ICU 4.6
UIDNA_ERROR_INVALID_ACE_LABEL 

An ACE label does not contain a valid label string.

The label was successfully ACE (Punycode) decoded but the resulting string had severe validation errors. For example, it might contain characters that are not allowed in ACE labels, or it might not be normalized.

Stable:
ICU 4.6
UIDNA_ERROR_BIDI 

A label does not meet the IDNA BiDi requirements (for right-to-left characters).

Stable:
ICU 4.6
UIDNA_ERROR_CONTEXTJ 

A label does not meet the IDNA CONTEXTJ requirements.

Stable:
ICU 4.6
UIDNA_ERROR_CONTEXTO_PUNCTUATION 

A label does not meet the IDNA CONTEXTO requirements for punctuation characters.

Some punctuation characters "Would otherwise have been DISALLOWED" but are allowed in certain contexts. (RFC 5892)

Stable:
ICU 49
UIDNA_ERROR_CONTEXTO_DIGITS 

A label does not meet the IDNA CONTEXTO requirements for digits.

Arabic-Indic Digits (U+066x) must not be mixed with Extended Arabic-Indic Digits (U+06Fx).

Stable:
ICU 49

Definition at line 421 of file uidna.h.

Function Documentation

§ uidna_close()

void uidna_close ( UIDNA idna)

Closes a UIDNA instance.

Parameters
idnaUIDNA instance to be closed
Stable:
ICU 4.6

§ uidna_compare()

int32_t uidna_compare ( const UChar s1,
int32_t  length1,
const UChar s2,
int32_t  length2,
int32_t  options,
UErrorCode status 
)

IDNA2003: Compare two IDN strings for equivalence.

This function splits the domain names into labels and compares them. According to IDN RFC, whenever two labels are compared, they are considered equal if and only if their ASCII forms (obtained by applying toASCII) match using an case-insensitive ASCII comparison. Two domain names are considered a match if and only if all labels match regardless of whether label separators match.

Parameters
s1First source string.
length1Length of first source string, or -1 if NUL-terminated.
s2Second source string.
length2Length of second source string, or -1 if NUL-terminated.
optionsA bit set of options:
  • UIDNA_DEFAULT Use default options, i.e., do not process unassigned code points and do not use STD3 ASCII rules If unassigned code points are found the operation fails with U_UNASSIGNED_CODE_POINT_FOUND error code.
  • UIDNA_ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query operations If this option is set, the unassigned code points are in the input are treated as normal Unicode code points.
  • UIDNA_USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this option is set and the input does not satisfy STD3 rules, the operation will fail with U_IDNA_STD3_ASCII_RULES_ERROR
Parameters
statusICU error code in/out parameter. Must fulfill U_SUCCESS before the function call.
Returns
<0 or 0 or >0 as usual for string comparisons
Deprecated:
ICU 55 Use UTS #46 instead via uidna_openUTS46() or class IDNA.

§ uidna_IDNToASCII()

int32_t uidna_IDNToASCII ( const UChar src,
int32_t  srcLength,
UChar dest,
int32_t  destCapacity,
int32_t  options,
UParseError parseError,
UErrorCode status 
)

IDNA2003: Convenience function that implements the IDNToASCII operation as defined in the IDNA RFC.

This operation is done on complete domain names, e.g: "www.example.com". It is important to note that this operation can fail. If it fails, then the input domain name cannot be used as an Internationalized Domain Name and the application should have methods defined to deal with the failure.

Note: IDNA RFC specifies that a conformant application should divide a domain name into separate labels, decide whether to apply allowUnassigned and useSTD3ASCIIRules on each, and then convert. This function does not offer that level of granularity. The options once set will apply to all labels in the domain name

Parameters
srcInput UChar array containing IDN in Unicode.
srcLengthNumber of UChars in src, or -1 if NUL-terminated.
destOutput UChar array with ASCII (ACE encoded) IDN.
destCapacitySize of dest.
optionsA bit set of options:
  • UIDNA_DEFAULT Use default options, i.e., do not process unassigned code points and do not use STD3 ASCII rules If unassigned code points are found the operation fails with U_UNASSIGNED_CODE_POINT_FOUND error code.
  • UIDNA_ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query operations If this option is set, the unassigned code points are in the input are treated as normal Unicode code points.
  • UIDNA_USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this option is set and the input does not satisfy STD3 rules, the operation will fail with U_IDNA_STD3_ASCII_RULES_ERROR
Parameters
parseErrorPointer to UParseError struct to receive information on position of error if an error is encountered. Can be NULL.
statusICU in/out error code parameter. U_INVALID_CHAR_FOUND if src contains unmatched single surrogates. U_INDEX_OUTOFBOUNDS_ERROR if src contains too many code points. U_BUFFER_OVERFLOW_ERROR if destCapacity is not enough
Returns
The length of the result string, if successful - or in case of a buffer overflow, in which case it will be greater than destCapacity.
Deprecated:
ICU 55 Use UTS #46 instead via uidna_openUTS46() or class IDNA.

§ uidna_IDNToUnicode()

int32_t uidna_IDNToUnicode ( const UChar src,
int32_t  srcLength,
UChar dest,
int32_t  destCapacity,
int32_t  options,
UParseError parseError,
UErrorCode status 
)

IDNA2003: Convenience function that implements the IDNToUnicode operation as defined in the IDNA RFC.

This operation is done on complete domain names, e.g: "www.example.com".

Note: IDNA RFC specifies that a conformant application should divide a domain name into separate labels, decide whether to apply allowUnassigned and useSTD3ASCIIRules on each, and then convert. This function does not offer that level of granularity. The options once set will apply to all labels in the domain name

Parameters
srcInput UChar array containing IDN in ASCII (ACE encoded) form.
srcLengthNumber of UChars in src, or -1 if NUL-terminated.
destOutput UChar array containing Unicode equivalent of source IDN.
destCapacitySize of dest.
optionsA bit set of options:
  • UIDNA_DEFAULT Use default options, i.e., do not process unassigned code points and do not use STD3 ASCII rules If unassigned code points are found the operation fails with U_UNASSIGNED_CODE_POINT_FOUND error code.
  • UIDNA_ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query operations If this option is set, the unassigned code points are in the input are treated as normal Unicode code points.
  • UIDNA_USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this option is set and the input does not satisfy STD3 rules, the operation will fail with U_IDNA_STD3_ASCII_RULES_ERROR
Parameters
parseErrorPointer to UParseError struct to receive information on position of error if an error is encountered. Can be NULL.
statusICU in/out error code parameter. U_INVALID_CHAR_FOUND if src contains unmatched single surrogates. U_INDEX_OUTOFBOUNDS_ERROR if src contains too many code points. U_BUFFER_OVERFLOW_ERROR if destCapacity is not enough
Returns
The length of the result string, if successful - or in case of a buffer overflow, in which case it will be greater than destCapacity.
Deprecated:
ICU 55 Use UTS #46 instead via uidna_openUTS46() or class IDNA.

§ uidna_labelToASCII()

int32_t uidna_labelToASCII ( const UIDNA idna,
const UChar label,
int32_t  length,
UChar dest,
int32_t  capacity,
UIDNAInfo pInfo,
UErrorCode pErrorCode 
)

Converts a single domain name label into its ASCII form for DNS lookup.

If any processing step fails, then pInfo->errors will be non-zero and the result might not be an ASCII string. The label might be modified according to the types of errors. Labels with severe errors will be left in (or turned into) their Unicode form.

The UErrorCode indicates an error only in exceptional cases, such as a U_MEMORY_ALLOCATION_ERROR.

Parameters
idnaUIDNA instance
labelInput domain name label
lengthLabel length, or -1 if NUL-terminated
destDestination string buffer
capacityDestination buffer capacity
pInfoOutput container of IDNA processing details.
pErrorCodeStandard ICU error code. Its input value must pass the U_SUCCESS() test, or else the function returns immediately. Check for U_FAILURE() on output or use with function chaining. (See User Guide for details.)
Returns
destination string length
Stable:
ICU 4.6

§ uidna_labelToASCII_UTF8()

int32_t uidna_labelToASCII_UTF8 ( const UIDNA idna,
const char *  label,
int32_t  length,
char *  dest,
int32_t  capacity,
UIDNAInfo pInfo,
UErrorCode pErrorCode 
)

Converts a single domain name label into its ASCII form for DNS lookup.

UTF-8 version of uidna_labelToASCII(), same behavior.

Parameters
idnaUIDNA instance
labelInput domain name label
lengthLabel length, or -1 if NUL-terminated
destDestination string buffer
capacityDestination buffer capacity
pInfoOutput container of IDNA processing details.
pErrorCodeStandard ICU error code. Its input value must pass the U_SUCCESS() test, or else the function returns immediately. Check for U_FAILURE() on output or use with function chaining. (See User Guide for details.)
Returns
destination string length
Stable:
ICU 4.6

§ uidna_labelToUnicode()

int32_t uidna_labelToUnicode ( const UIDNA idna,
const UChar label,
int32_t  length,
UChar dest,
int32_t  capacity,
UIDNAInfo pInfo,
UErrorCode pErrorCode 
)

Converts a single domain name label into its Unicode form for human-readable display.

If any processing step fails, then pInfo->errors will be non-zero. The label might be modified according to the types of errors.

The UErrorCode indicates an error only in exceptional cases, such as a U_MEMORY_ALLOCATION_ERROR.

Parameters
idnaUIDNA instance
labelInput domain name label
lengthLabel length, or -1 if NUL-terminated
destDestination string buffer
capacityDestination buffer capacity
pInfoOutput container of IDNA processing details.
pErrorCodeStandard ICU error code. Its input value must pass the U_SUCCESS() test, or else the function returns immediately. Check for U_FAILURE() on output or use with function chaining. (See User Guide for details.)
Returns
destination string length
Stable:
ICU 4.6

§ uidna_labelToUnicodeUTF8()

int32_t uidna_labelToUnicodeUTF8 ( const UIDNA idna,
const char *  label,
int32_t  length,
char *  dest,
int32_t  capacity,
UIDNAInfo pInfo,
UErrorCode pErrorCode 
)

Converts a single domain name label into its Unicode form for human-readable display.

UTF-8 version of uidna_labelToUnicode(), same behavior.

Parameters
idnaUIDNA instance
labelInput domain name label
lengthLabel length, or -1 if NUL-terminated
destDestination string buffer
capacityDestination buffer capacity
pInfoOutput container of IDNA processing details.
pErrorCodeStandard ICU error code. Its input value must pass the U_SUCCESS() test, or else the function returns immediately. Check for U_FAILURE() on output or use with function chaining. (See User Guide for details.)
Returns
destination string length
Stable:
ICU 4.6

§ uidna_nameToASCII()

int32_t uidna_nameToASCII ( const UIDNA idna,
const UChar name,
int32_t  length,
UChar dest,
int32_t  capacity,
UIDNAInfo pInfo,
UErrorCode pErrorCode 
)

Converts a whole domain name into its ASCII form for DNS lookup.

If any processing step fails, then pInfo->errors will be non-zero and the result might not be an ASCII string. The domain name might be modified according to the types of errors. Labels with severe errors will be left in (or turned into) their Unicode form.

The UErrorCode indicates an error only in exceptional cases, such as a U_MEMORY_ALLOCATION_ERROR.

Parameters
idnaUIDNA instance
nameInput domain name
lengthDomain name length, or -1 if NUL-terminated
destDestination string buffer
capacityDestination buffer capacity
pInfoOutput container of IDNA processing details.
pErrorCodeStandard ICU error code. Its input value must pass the U_SUCCESS() test, or else the function returns immediately. Check for U_FAILURE() on output or use with function chaining. (See User Guide for details.)
Returns
destination string length
Stable:
ICU 4.6

§ uidna_nameToASCII_UTF8()

int32_t uidna_nameToASCII_UTF8 ( const UIDNA idna,
const char *  name,
int32_t  length,
char *  dest,
int32_t  capacity,
UIDNAInfo pInfo,
UErrorCode pErrorCode 
)

Converts a whole domain name into its ASCII form for DNS lookup.

UTF-8 version of uidna_nameToASCII(), same behavior.

Parameters
idnaUIDNA instance
nameInput domain name
lengthDomain name length, or -1 if NUL-terminated
destDestination string buffer
capacityDestination buffer capacity
pInfoOutput container of IDNA processing details.
pErrorCodeStandard ICU error code. Its input value must pass the U_SUCCESS() test, or else the function returns immediately. Check for U_FAILURE() on output or use with function chaining. (See User Guide for details.)
Returns
destination string length
Stable:
ICU 4.6

§ uidna_nameToUnicode()

int32_t uidna_nameToUnicode ( const UIDNA idna,
const UChar name,
int32_t  length,
UChar dest,
int32_t  capacity,
UIDNAInfo pInfo,
UErrorCode pErrorCode 
)

Converts a whole domain name into its Unicode form for human-readable display.

If any processing step fails, then pInfo->errors will be non-zero. The domain name might be modified according to the types of errors.

The UErrorCode indicates an error only in exceptional cases, such as a U_MEMORY_ALLOCATION_ERROR.

Parameters
idnaUIDNA instance
nameInput domain name
lengthDomain name length, or -1 if NUL-terminated
destDestination string buffer
capacityDestination buffer capacity
pInfoOutput container of IDNA processing details.
pErrorCodeStandard ICU error code. Its input value must pass the U_SUCCESS() test, or else the function returns immediately. Check for U_FAILURE() on output or use with function chaining. (See User Guide for details.)
Returns
destination string length
Stable:
ICU 4.6

§ uidna_nameToUnicodeUTF8()

int32_t uidna_nameToUnicodeUTF8 ( const UIDNA idna,
const char *  name,
int32_t  length,
char *  dest,
int32_t  capacity,
UIDNAInfo pInfo,
UErrorCode pErrorCode 
)

Converts a whole domain name into its Unicode form for human-readable display.

UTF-8 version of uidna_nameToUnicode(), same behavior.

Parameters
idnaUIDNA instance
nameInput domain name
lengthDomain name length, or -1 if NUL-terminated
destDestination string buffer
capacityDestination buffer capacity
pInfoOutput container of IDNA processing details.
pErrorCodeStandard ICU error code. Its input value must pass the U_SUCCESS() test, or else the function returns immediately. Check for U_FAILURE() on output or use with function chaining. (See User Guide for details.)
Returns
destination string length
Stable:
ICU 4.6

§ uidna_openUTS46()

UIDNA* uidna_openUTS46 ( uint32_t  options,
UErrorCode pErrorCode 
)

Returns a UIDNA instance which implements UTS #46.

Returns an unmodifiable instance, owned by the caller. Cache it for multiple operations, and uidna_close() it when done. The instance is thread-safe, that is, it can be used concurrently.

For details about the UTS #46 implementation see the IDNA C++ class in idna.h.

Parameters
optionsBit set to modify the processing and error checking. See option bit set values in uidna.h.
pErrorCodeStandard ICU error code. Its input value must pass the U_SUCCESS() test, or else the function returns immediately. Check for U_FAILURE() on output or use with function chaining. (See User Guide for details.)
Returns
the UTS #46 UIDNA instance, if successful
Stable:
ICU 4.6

§ uidna_toASCII()

int32_t uidna_toASCII ( const UChar src,
int32_t  srcLength,
UChar dest,
int32_t  destCapacity,
int32_t  options,
UParseError parseError,
UErrorCode status 
)

IDNA2003: This function implements the ToASCII operation as defined in the IDNA RFC.

This operation is done on single labels before sending it to something that expects ASCII names. A label is an individual part of a domain name. Labels are usually separated by dots; e.g. "www.example.com" is composed of 3 labels "www","example", and "com".

IDNA2003 API Overview:

The uidna_ API implements the IDNA protocol as defined in the IDNA RFC (http://www.ietf.org/rfc/rfc3490.txt). The RFC defines 2 operations: ToASCII and ToUnicode. Domain name labels containing non-ASCII code points are processed by the ToASCII operation before passing it to resolver libraries. Domain names that are obtained from resolver libraries are processed by the ToUnicode operation before displaying the domain name to the user. IDNA requires that implementations process input strings with Nameprep (http://www.ietf.org/rfc/rfc3491.txt), which is a profile of Stringprep (http://www.ietf.org/rfc/rfc3454.txt), and then with Punycode (http://www.ietf.org/rfc/rfc3492.txt). Implementations of IDNA MUST fully implement Nameprep and Punycode; neither Nameprep nor Punycode are optional. The input and output of ToASCII and ToUnicode operations are Unicode and are designed to be chainable, i.e., applying ToASCII or ToUnicode operations multiple times to an input string will yield the same result as applying the operation once. ToUnicode(ToUnicode(ToUnicode...(ToUnicode(string)))) == ToUnicode(string) ToASCII(ToASCII(ToASCII...(ToASCII(string))) == ToASCII(string).

Parameters
srcInput UChar array containing label in Unicode.
srcLengthNumber of UChars in src, or -1 if NUL-terminated.
destOutput UChar array with ASCII (ACE encoded) label.
destCapacitySize of dest.
optionsA bit set of options:
  • UIDNA_DEFAULT Use default options, i.e., do not process unassigned code points and do not use STD3 ASCII rules If unassigned code points are found the operation fails with U_UNASSIGNED_ERROR error code.
  • UIDNA_ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query operations If this option is set, the unassigned code points are in the input are treated as normal Unicode code points.
  • UIDNA_USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this option is set and the input does not satisfy STD3 rules, the operation will fail with U_IDNA_STD3_ASCII_RULES_ERROR
Parameters
parseErrorPointer to UParseError struct to receive information on position of error if an error is encountered. Can be NULL.
statusICU in/out error code parameter. U_INVALID_CHAR_FOUND if src contains unmatched single surrogates. U_INDEX_OUTOFBOUNDS_ERROR if src contains too many code points. U_BUFFER_OVERFLOW_ERROR if destCapacity is not enough
Returns
The length of the result string, if successful - or in case of a buffer overflow, in which case it will be greater than destCapacity.
Deprecated:
ICU 55 Use UTS #46 instead via uidna_openUTS46() or class IDNA.

§ uidna_toUnicode()

int32_t uidna_toUnicode ( const UChar src,
int32_t  srcLength,
UChar dest,
int32_t  destCapacity,
int32_t  options,
UParseError parseError,
UErrorCode status 
)

IDNA2003: This function implements the ToUnicode operation as defined in the IDNA RFC.

This operation is done on single labels before sending it to something that expects Unicode names. A label is an individual part of a domain name. Labels are usually separated by dots; for e.g. "www.example.com" is composed of 3 labels "www","example", and "com".

Parameters
srcInput UChar array containing ASCII (ACE encoded) label.
srcLengthNumber of UChars in src, or -1 if NUL-terminated.
destOutput Converted UChar array containing Unicode equivalent of label.
destCapacitySize of dest.
optionsA bit set of options:
  • UIDNA_DEFAULT Use default options, i.e., do not process unassigned code points and do not use STD3 ASCII rules If unassigned code points are found the operation fails with U_UNASSIGNED_ERROR error code.
  • UIDNA_ALLOW_UNASSIGNED Unassigned values can be converted to ASCII for query operations If this option is set, the unassigned code points are in the input are treated as normal Unicode code points. Note: This option is required on toUnicode operation because the RFC mandates verification of decoded ACE input by applying toASCII and comparing its output with source
  • UIDNA_USE_STD3_RULES Use STD3 ASCII rules for host name syntax restrictions If this option is set and the input does not satisfy STD3 rules, the operation will fail with U_IDNA_STD3_ASCII_RULES_ERROR
Parameters
parseErrorPointer to UParseError struct to receive information on position of error if an error is encountered. Can be NULL.
statusICU in/out error code parameter. U_INVALID_CHAR_FOUND if src contains unmatched single surrogates. U_INDEX_OUTOFBOUNDS_ERROR if src contains too many code points. U_BUFFER_OVERFLOW_ERROR if destCapacity is not enough
Returns
The length of the result string, if successful - or in case of a buffer overflow, in which case it will be greater than destCapacity.
Deprecated:
ICU 55 Use UTS #46 instead via uidna_openUTS46() or class IDNA.