ICU 75.1 75.1

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 <stdbool.h>`
`#include "unicode/parseerr.h"`
`#include "unicode/localpointer.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
U_CAPI UIDNA * | uidna_openUTS46 (uint32_t options, UErrorCode *pErrorCode)
| Returns a UIDNA instance which implements UTS #46. More...
U_CAPI void | uidna_close (UIDNA *idna)
| Closes a UIDNA instance. More...
U_CAPI 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...
U_CAPI 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...
U_CAPI 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...
U_CAPI 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...
U_CAPI 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...
U_CAPI 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...
U_CAPI 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...
U_CAPI 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 }
UIDNAInfo
Output container for IDNA processing errors.
Definition: uidna.h:185

Static initializer for a UIDNAInfo struct.

Stable:
  ICU 4.6

Definition at line 209 of file uidna.h.

## Typedef Documentation

## ◆ UIDNA

typedef struct UIDNA UIDNA

C typedef for struct UIDNA.

Stable:
  ICU 4.6

Definition at line 1 of file uidna.h.

## ◆ UIDNAInfo

typedef struct UIDNAInfo UIDNAInfo

Output container for IDNA processing errors.

Initialize with UIDNA_INFO_INITIALIZER:

UIDNAInfo info = UIDNA_INFO_INITIALIZER;
int32_t length = uidna_nameToASCII(..., &info, &errorCode);
if(U_SUCCESS(errorCode) && info.errors!=0) { ... }
UIDNAInfo::errors
uint32_t errors
Bit set indicating IDNA processing errors.
Definition: uidna.h:200
UIDNA_INFO_INITIALIZER
#define UIDNA_INFO_INITIALIZER
Static initializer for a UIDNAInfo struct.
Definition: uidna.h:209
uidna_nameToASCII
U_CAPI 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.
U_SUCCESS
#define U_SUCCESS(x)
Does the error code indicate success?
Definition: utypes.h:728

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 50 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 425 of file uidna.h.

## Function Documentation

## ◆ uidna_close()

U_CAPI void uidna_close | ( | UIDNA * | idna | ) |

Closes a UIDNA instance.

Parameters

  idna | UIDNA 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

  s1 | First source string.
  length1 | Length of first source string, or -1 if NUL-terminated.
  s2 | Second source string.
  length2 | Length of second source string, or -1 if NUL-terminated.
  options | A 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

  status | ICU 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

  src | Input UChar array containing IDN in Unicode.
  srcLength | Number of UChars in src, or -1 if NUL-terminated.
  dest | Output UChar array with ASCII (ACE encoded) IDN.
  destCapacity | Size of dest.
  options | A 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

  parseError | Pointer to UParseError struct to receive information on position of error if an error is encountered. Can be NULL.
  status | ICU 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

  src | Input UChar array containing IDN in ASCII (ACE encoded) form.
  srcLength | Number of UChars in src, or -1 if NUL-terminated.
  dest | Output UChar array containing Unicode equivalent of source IDN.
  destCapacity | Size of dest.
  options | A 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

  parseError | Pointer to UParseError struct to receive information on position of error if an error is encountered. Can be NULL.
  status | ICU 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()

U_CAPI 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

  idna | UIDNA instance
  label | Input domain name label
  length | Label length, or -1 if NUL-terminated
  dest | Destination string buffer
  capacity | Destination buffer capacity
  pInfo | Output container of IDNA processing details.
  pErrorCode | Standard 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()

U_CAPI 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

  idna | UIDNA instance
  label | Input domain name label
  length | Label length, or -1 if NUL-terminated
  dest | Destination string buffer
  capacity | Destination buffer capacity
  pInfo | Output container of IDNA processing details.
  pErrorCode | Standard 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()

U_CAPI 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

  idna | UIDNA instance
  label | Input domain name label
  length | Label length, or -1 if NUL-terminated
  dest | Destination string buffer
  capacity | Destination buffer capacity
  pInfo | Output container of IDNA processing details.
  pErrorCode | Standard 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()

U_CAPI 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

  idna | UIDNA instance
  label | Input domain name label
  length | Label length, or -1 if NUL-terminated
  dest | Destination string buffer
  capacity | Destination buffer capacity
  pInfo | Output container of IDNA processing details.
  pErrorCode | Standard 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()

U_CAPI 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

  idna | UIDNA instance
  name | Input domain name
  length | Domain name length, or -1 if NUL-terminated
  dest | Destination string buffer
  capacity | Destination buffer capacity
  pInfo | Output container of IDNA processing details.
  pErrorCode | Standard 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()

U_CAPI 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

  idna | UIDNA instance
  name | Input domain name
  length | Domain name length, or -1 if NUL-terminated
  dest | Destination string buffer
  capacity | Destination buffer capacity
  pInfo | Output container of IDNA processing details.
  pErrorCode | Standard 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()

U_CAPI 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

  idna | UIDNA instance
  name | Input domain name
  length | Domain name length, or -1 if NUL-terminated
  dest | Destination string buffer
  capacity | Destination buffer capacity
  pInfo | Output container of IDNA processing details.
  pErrorCode | Standard 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()

U_CAPI 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

  idna | UIDNA instance
  name | Input domain name
  length | Domain name length, or -1 if NUL-terminated
  dest | Destination string buffer
  capacity | Destination buffer capacity
  pInfo | Output container of IDNA processing details.
  pErrorCode | Standard 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()

U_CAPI 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

  options | Bit set to modify the processing and error checking. See option bit set values in uidna.h.
  pErrorCode | Standard 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

  src | Input UChar array containing label in Unicode.
  srcLength | Number of UChars in src, or -1 if NUL-terminated.
  dest | Output UChar array with ASCII (ACE encoded) label.
  destCapacity | Size of dest.
  options | A 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

  parseError | Pointer to UParseError struct to receive information on position of error if an error is encountered. Can be NULL.
  status | ICU 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

  src | Input UChar array containing ASCII (ACE encoded) label.
  srcLength | Number of UChars in src, or -1 if NUL-terminated.
  dest | Output Converted UChar array containing Unicode equivalent of label.
  destCapacity | Size of dest.
  options | A 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

  parseError | Pointer to UParseError struct to receive information on position of error if an error is encountered. Can be NULL.
  status | ICU 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.