Check in the pristine copy of ICU 4.6...

icu46/source/common/unicode/uidna.h

+/*
+ *******************************************************************************
+ *
+ *   Copyright (C) 2003-2010, International Business Machines
+ *   Corporation and others.  All Rights Reserved.
+ *
+ *******************************************************************************
+ *   file name:  uidna.h
+ *   encoding:   US-ASCII
+ *   tab size:   8 (not used)
+ *   indentation:4
+ *
+ *   created on: 2003feb1
+ *   created by: Ram Viswanadha
+ */
+
+#ifndef __UIDNA_H__
+#define __UIDNA_H__
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_IDNA
+
+#include "unicode/localpointer.h"
+#include "unicode/parseerr.h"
+
+/**
+ * \file
+ * \brief 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.
+ * The C API functions which do not take a service object pointer
+ * implement IDNA2003.
+ */
+
+/*
+ * IDNA option bit set values.
+ */
+enum {
+    /**
+     * Default options value: None of the other options are set.
+     * @stable ICU 2.6
+     */
+    UIDNA_DEFAULT=0,
+    /**
+     * Option to allow unassigned code points in domain names and labels.
+     * This option is ignored by the UTS46 implementation.
+     * (UTS #46 disallows unassigned code points.)
+     * @stable ICU 2.6
+     */
+    UIDNA_ALLOW_UNASSIGNED=1,
+    /**
+     * 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).
+     * @stable ICU 2.6
+     */
+    UIDNA_USE_STD3_RULES=2,
+    /**
+     * IDNA option to check for whether the input conforms to the BiDi rules.
+     * This option is ignored by the IDNA2003 implementation.
+     * (IDNA2003 always performs a BiDi check.)
+     * @draft ICU 4.6
+     */
+    UIDNA_CHECK_BIDI=4,
+    /**
+     * IDNA option to check for whether the input conforms to the CONTEXTJ rules.
+     * This option is ignored by the IDNA2003 implementation.
+     * (The CONTEXTJ check is new in IDNA2008.)
+     * @draft ICU 4.6
+     */
+    UIDNA_CHECK_CONTEXTJ=8,
+    /**
+     * IDNA option for nontransitional processing in ToASCII().
+     * 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.)
+     * @draft ICU 4.6
+     */
+    UIDNA_NONTRANSITIONAL_TO_ASCII=0x10,
+    /**
+     * IDNA option for nontransitional processing in ToUnicode().
+     * 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.)
+     * @draft ICU 4.6
+     */
+    UIDNA_NONTRANSITIONAL_TO_UNICODE=0x20
+};
+
+/**
+ * Opaque C service object type for the new IDNA API.
+ * @draft ICU 4.6
+ */
+struct UIDNA;
+typedef struct UIDNA UIDNA;  /**< C typedef for struct UIDNA. @draft ICU 4.6 */
+
+/**
+ * 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.
+ *
+ * @param options Bit set to modify the processing and error checking.
+ *                See option bit set values in uidna.h.
+ * @param 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.)
+ * @return the UTS #46 UIDNA instance, if successful
+ * @draft ICU 4.6
+ */
+U_DRAFT UIDNA * U_EXPORT2
+uidna_openUTS46(uint32_t options, UErrorCode *pErrorCode);
+
+/**
+ * Closes a UIDNA instance.
+ * @param idna UIDNA instance to be closed
+ * @draft ICU 4.6
+ */
+U_DRAFT void U_EXPORT2
+uidna_close(UIDNA *idna);
+
+#if U_SHOW_CPLUSPLUS_API
+
+U_NAMESPACE_BEGIN
+
+/**
+ * \class LocalUIDNAPointer
+ * "Smart pointer" class, closes a UIDNA via uidna_close().
+ * For most methods see the LocalPointerBase base class.
+ *
+ * @see LocalPointerBase
+ * @see LocalPointer
+ * @draft ICU 4.6
+ */
+U_DEFINE_LOCAL_OPEN_POINTER(LocalUIDNAPointer, UIDNA, uidna_close);
+
+U_NAMESPACE_END
+
+#endif
+
+/**
+ * Output container for IDNA processing errors.
+ * Initialize with UIDNA_INFO_INITIALIZER:
+ * \code
+ * UIDNAInfo info = UIDNA_INFO_INITIALIZER;
+ * int32_t length = uidna_nameToASCII(..., &info, &errorCode);
+ * if(U_SUCCESS(errorCode) && info.errors!=0) { ... }
+ * \endcode
+ * @draft ICU 4.6
+ */
+struct UIDNAInfo {
+    /** sizeof(UIDNAInfo) @draft ICU 4.6 */
+    int16_t size;
+    /**
+     * Set to TRUE if transitional and nontransitional processing produce different results.
+     * For details see C++ IDNAInfo::isTransitionalDifferent().
+     * @draft ICU 4.6
+     */
+    UBool isTransitionalDifferent;
+    UBool reservedB3;  /**< Reserved field, do not use. @internal */
+    /**
+     * Bit set indicating IDNA processing errors. 0 if no errors.
+     * See UIDNA_ERROR_... constants.
+     * @draft ICU 4.6
+     */
+    uint32_t errors;
+    int32_t reservedI2;  /**< Reserved field, do not use. @internal */
+    int32_t reservedI3;  /**< Reserved field, do not use. @internal */
+};
+typedef struct UIDNAInfo UIDNAInfo;
+
+/**
+ * Static initializer for a UIDNAInfo struct.
+ * @draft ICU 4.6
+ */
+#define UIDNA_INFO_INITIALIZER { \
+    (int16_t)sizeof(UIDNAInfo), \
+    FALSE, FALSE, \
+    0, 0, 0 }
+
+/**
+ * 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.
+ *
+ * @param idna UIDNA instance
+ * @param label Input domain name label
+ * @param length Label length, or -1 if NUL-terminated
+ * @param dest Destination string buffer
+ * @param capacity Destination buffer capacity
+ * @param pInfo Output container of IDNA processing details.
+ * @param 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.)
+ * @return destination string length
+ * @draft ICU 4.6
+ */
+U_DRAFT int32_t U_EXPORT2
+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 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.
+ *
+ * @param idna UIDNA instance
+ * @param label Input domain name label
+ * @param length Label length, or -1 if NUL-terminated
+ * @param dest Destination string buffer
+ * @param capacity Destination buffer capacity
+ * @param pInfo Output container of IDNA processing details.
+ * @param 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.)
+ * @return destination string length
+ * @draft ICU 4.6
+ */
+U_DRAFT int32_t U_EXPORT2
+uidna_labelToUnicode(const UIDNA *idna,
+                     const UChar *label, 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.
+ *
+ * @param idna UIDNA instance
+ * @param name Input domain name
+ * @param length Domain name length, or -1 if NUL-terminated
+ * @param dest Destination string buffer
+ * @param capacity Destination buffer capacity
+ * @param pInfo Output container of IDNA processing details.
+ * @param 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.)
+ * @return destination string length
+ * @draft ICU 4.6
+ */
+U_DRAFT int32_t U_EXPORT2
+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 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.
+ *
+ * @param idna UIDNA instance
+ * @param name Input domain name
+ * @param length Domain name length, or -1 if NUL-terminated
+ * @param dest Destination string buffer
+ * @param capacity Destination buffer capacity
+ * @param pInfo Output container of IDNA processing details.
+ * @param 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.)
+ * @return destination string length
+ * @draft ICU 4.6
+ */
+U_DRAFT int32_t U_EXPORT2
+uidna_nameToUnicode(const UIDNA *idna,
+                    const UChar *name, int32_t length,
+                    UChar *dest, int32_t capacity,
+                    UIDNAInfo *pInfo, UErrorCode *pErrorCode);
+
+/* UTF-8 versions of the processing methods --------------------------------- */
+
+/**
+ * Converts a single domain name label into its ASCII form for DNS lookup.
+ * UTF-8 version of uidna_labelToASCII(), same behavior.
+ *
+ * @param idna UIDNA instance
+ * @param label Input domain name label
+ * @param length Label length, or -1 if NUL-terminated
+ * @param dest Destination string buffer
+ * @param capacity Destination buffer capacity
+ * @param pInfo Output container of IDNA processing details.
+ * @param 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.)
+ * @return destination string length
+ * @draft ICU 4.6
+ */
+U_DRAFT int32_t U_EXPORT2
+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 Unicode form for human-readable display.
+ * UTF-8 version of uidna_labelToUnicode(), same behavior.
+ *
+ * @param idna UIDNA instance
+ * @param label Input domain name label
+ * @param length Label length, or -1 if NUL-terminated
+ * @param dest Destination string buffer
+ * @param capacity Destination buffer capacity
+ * @param pInfo Output container of IDNA processing details.
+ * @param 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.)
+ * @return destination string length
+ * @draft ICU 4.6
+ */
+U_DRAFT int32_t U_EXPORT2
+uidna_labelToUnicodeUTF8(const UIDNA *idna,
+                         const char *label, 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.
+ *
+ * @param idna UIDNA instance
+ * @param name Input domain name
+ * @param length Domain name length, or -1 if NUL-terminated
+ * @param dest Destination string buffer
+ * @param capacity Destination buffer capacity
+ * @param pInfo Output container of IDNA processing details.
+ * @param 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.)
+ * @return destination string length
+ * @draft ICU 4.6
+ */
+U_DRAFT int32_t U_EXPORT2
+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 Unicode form for human-readable display.
+ * UTF-8 version of uidna_nameToUnicode(), same behavior.
+ *
+ * @param idna UIDNA instance
+ * @param name Input domain name
+ * @param length Domain name length, or -1 if NUL-terminated
+ * @param dest Destination string buffer
+ * @param capacity Destination buffer capacity
+ * @param pInfo Output container of IDNA processing details.
+ * @param 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.)
+ * @return destination string length
+ * @draft ICU 4.6
+ */
+U_DRAFT int32_t U_EXPORT2
+uidna_nameToUnicodeUTF8(const UIDNA *idna,
+                        const char *name, int32_t length,
+                        char *dest, int32_t capacity,
+                        UIDNAInfo *pInfo, UErrorCode *pErrorCode);
+
+/*
+ * IDNA error bit set values.
+ * When a domain name or label fails a processing step or does not meet the
+ * validity criteria, then one or more of these error bits are set.
+ */
+enum {
+    /**
+     * A non-final domain name label (or the whole domain name) is empty.
+     * @draft ICU 4.6
+     */
+    UIDNA_ERROR_EMPTY_LABEL=1,
+    /**
+     * 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.
+     * @draft ICU 4.6
+     */
+    UIDNA_ERROR_LABEL_TOO_LONG=2,
+    /**
+     * 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.
+     * @draft ICU 4.6
+     */
+    UIDNA_ERROR_DOMAIN_NAME_TOO_LONG=4,
+    /**
+     * A label starts with a hyphen-minus ('-').
+     * @draft ICU 4.6
+     */
+    UIDNA_ERROR_LEADING_HYPHEN=8,
+    /**
+     * A label ends with a hyphen-minus ('-').
+     * @draft ICU 4.6
+     */
+    UIDNA_ERROR_TRAILING_HYPHEN=0x10,
+    /**
+     * A label contains hyphen-minus ('-') in the third and fourth positions.
+     * @draft ICU 4.6
+     */
+    UIDNA_ERROR_HYPHEN_3_4=0x20,
+    /**
+     * A label starts with a combining mark.
+     * @draft ICU 4.6
+     */
+    UIDNA_ERROR_LEADING_COMBINING_MARK=0x40,
+    /**
+     * A label or domain name contains disallowed characters.
+     * @draft ICU 4.6
+     */
+    UIDNA_ERROR_DISALLOWED=0x80,
+    /**
+     * A label starts with "xn--" but does not contain valid Punycode.
+     * That is, an xn-- label failed Punycode decoding.
+     * @draft ICU 4.6
+     */
+    UIDNA_ERROR_PUNYCODE=0x100,
+    /**
+     * A label contains a dot=full stop.
+     * This can occur in an input string for a single-label function.
+     * @draft ICU 4.6
+     */
+    UIDNA_ERROR_LABEL_HAS_DOT=0x200,
+    /**
+     * 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.
+     * @draft ICU 4.6
+     */
+    UIDNA_ERROR_INVALID_ACE_LABEL=0x400,
+    /**
+     * A label does not meet the IDNA BiDi requirements (for right-to-left characters).
+     * @draft ICU 4.6
+     */
+    UIDNA_ERROR_BIDI=0x800,
+    /**
+     * A label does not meet the IDNA CONTEXTJ requirements.
+     * @draft ICU 4.6
+     */
+    UIDNA_ERROR_CONTEXTJ=0x1000
+};
+
+/* IDNA2003 API ------------------------------------------------------------- */
+
+/**
+ * IDNA2003: This function implements the ToASCII operation as defined in the IDNA RFC.
+ * This operation is done on <b>single labels</b> 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).
+ *
+ * @param src               Input UChar array containing label in Unicode.
+ * @param srcLength         Number of UChars in src, or -1 if NUL-terminated.
+ * @param dest              Output UChar array with ASCII (ACE encoded) label.
+ * @param destCapacity      Size of dest.
+ * @param 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
+ *
+ * @param parseError        Pointer to UParseError struct to receive information on position 
+ *                          of error if an error is encountered. Can be NULL.
+ * @param 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
+ * @return The length of the result string, if successful - or in case of a buffer overflow,
+ *         in which case it will be greater than destCapacity.
+ * @stable ICU 2.6
+ */
+U_STABLE int32_t U_EXPORT2
+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 ToUnicode operation as defined in the IDNA RFC.
+ * This operation is done on <b>single labels</b> 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".
+ *
+ * @param src               Input UChar array containing ASCII (ACE encoded) label.
+ * @param srcLength         Number of UChars in src, or -1 if NUL-terminated.
+ * @param dest Output       Converted UChar array containing Unicode equivalent of label.
+ * @param destCapacity      Size of dest.
+ * @param 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. <b> Note: </b> 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
+ *
+ * @param parseError        Pointer to UParseError struct to receive information on position 
+ *                          of error if an error is encountered. Can be NULL.
+ * @param 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
+ * @return The length of the result string, if successful - or in case of a buffer overflow,
+ *         in which case it will be greater than destCapacity.
+ * @stable ICU 2.6
+ */
+U_STABLE int32_t U_EXPORT2
+uidna_toUnicode(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.
+ *
+ * <b>Note:</b> 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
+ *
+ * @param src               Input UChar array containing IDN in Unicode.
+ * @param srcLength         Number of UChars in src, or -1 if NUL-terminated.
+ * @param dest              Output UChar array with ASCII (ACE encoded) IDN.
+ * @param destCapacity      Size of dest.
+ * @param 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
+ *
+ * @param parseError        Pointer to UParseError struct to receive information on position 
+ *                          of error if an error is encountered. Can be NULL.
+ * @param 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
+ * @return The length of the result string, if successful - or in case of a buffer overflow,
+ *         in which case it will be greater than destCapacity.
+ * @stable ICU 2.6
+ */
+U_STABLE int32_t U_EXPORT2
+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 IDNToUnicode operation as defined in the IDNA RFC.
+ * This operation is done on complete domain names, e.g: "www.example.com". 
+ *
+ * <b>Note:</b> 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
+ *
+ * @param src               Input UChar array containing IDN in ASCII (ACE encoded) form.
+ * @param srcLength         Number of UChars in src, or -1 if NUL-terminated.
+ * @param dest Output       UChar array containing Unicode equivalent of source IDN.
+ * @param destCapacity      Size of dest.
+ * @param 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
+ *
+ * @param parseError        Pointer to UParseError struct to receive information on position 
+ *                          of error if an error is encountered. Can be NULL.
+ * @param 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
+ * @return The length of the result string, if successful - or in case of a buffer overflow,
+ *         in which case it will be greater than destCapacity.
+ * @stable ICU 2.6
+ */
+U_STABLE int32_t U_EXPORT2
+uidna_IDNToUnicode(  const UChar* src, int32_t srcLength,
+                     UChar* dest, int32_t destCapacity,
+                     int32_t options,
+                     UParseError* parseError,
+                     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.
+ *
+ * @param s1                First source string.
+ * @param length1           Length of first source string, or -1 if NUL-terminated.
+ *
+ * @param s2                Second source string.
+ * @param length2           Length of second source string, or -1 if NUL-terminated.
+ * @param 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
+ *
+ * @param status            ICU error code in/out parameter.
+ *                          Must fulfill U_SUCCESS before the function call.
+ * @return <0 or 0 or >0 as usual for string comparisons
+ * @stable ICU 2.6
+ */
+U_STABLE int32_t U_EXPORT2
+uidna_compare(  const UChar *s1, int32_t length1,
+                const UChar *s2, int32_t length2,
+                int32_t options,
+                UErrorCode* status);
+
+#endif /* #if !UCONFIG_NO_IDNA */
+
+#endif