text: // Copyright (C) 2016 and later: Unicode, Inc. and others.
  // License & terms of use: http://www.unicode.org/copyright.html
  /*
   *******************************************************************************
   *
   *   Copyright (C) 2003-2014, 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.
   *
   * IDNA2003 is obsolete.
   * The C API functions which do not take a service object pointer
   * implement IDNA2003. They are all deprecated.
   */
  
  /*
   * IDNA option bit set values.
   */
  enum {
      /**
       * Default options value: None of the other options are set.
       * For use in static worker and factory methods.
       * @stable ICU 2.6
       */
      UIDNA_DEFAULT=0,
  #ifndef U_HIDE_DEPRECATED_API
      /**
       * Option to allow unassigned code points in domain names and labels.
       * For use in static worker and factory methods.
       * <p>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_ALLOW_UNASSIGNED=1,
  #endif  /* U_HIDE_DEPRECATED_API */
      /**
       * 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_USE_STD3_RULES=2,
      /**
       * IDNA option to check for whether the input conforms to the BiDi rules.
       * For use in static worker and factory methods.
       * <p>This option is ignored by the IDNA2003 implementation.
       * (IDNA2003 always performs a BiDi check.)
       * @stable ICU 4.6
       */
      UIDNA_CHECK_BIDI=4,
      /**
       * IDNA option to check for whether the input conforms to the CONTEXTJ rules.
       * For use in static worker and factory methods.
       * <p>This option is ignored by the IDNA2003 implementation.
       * (The CONTEXTJ check is new in IDNA2008.)
       * @stable ICU 4.6
       */
      UIDNA_CHECK_CONTEXTJ=8,
      /**
       * IDNA option for nontransitional processing in ToASCII().
       * For use in static worker and factory methods.
       * <p>By default, ToASCII() uses transitional processing.
       * <p>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_ASCII=0x10,
      /**
       * IDNA option for nontransitional processing in ToUnicode().
       * For use in static worker and factory methods.
       * <p>By default, ToUnicode() uses transitional processing.
       * <p>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=0x20,
      /**
       * IDNA option to check for whether the input conforms to the CONTEXTO rules.
       * For use in static worker and factory methods.
       * <p>This option is ignored by the IDNA2003 implementation.
       * (The CONTEXTO check is new in IDNA2008.)
       * <p>This is for use by registries for IDNA2008 conformance.
       * UTS #46 does not require the CONTEXTO check.
       * @stable ICU 49
       */
      UIDNA_CHECK_CONTEXTO=0x40
  };
  
  /**
   * Opaque C service object type for the new IDNA API.
   * @stable ICU 4.6
   */
  struct UIDNA;
  typedef struct UIDNA UIDNA;  /**< C typedef for struct UIDNA. @stable 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
   * @stable ICU 4.6
   */
  U_STABLE UIDNA * U_EXPORT2
  uidna_openUTS46(uint32_t options, UErrorCode *pErrorCode);
  
  /**
   * Closes a UIDNA instance.
   * @param idna UIDNA instance to be closed
   * @stable ICU 4.6
   */
  U_STABLE 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
   * @stable 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
   * @stable ICU 4.6
   */
  typedef struct UIDNAInfo {
      /** sizeof(UIDNAInfo) @stable ICU 4.6 */
      int16_t size;
      /**
       * Set to TRUE if transitional and nontransitional processing produce different results.
       * For details see C++ IDNAInfo::isTransitionalDifferent().
       * @stable 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.
       * @stable ICU 4.6
       */
      uint32_t errors;
      int32_t reservedI2;  /**< Reserved field, do not use. @internal */
      int32_t reservedI3;  /**< Reserved field, do not use. @internal */
  } UIDNAInfo;
  
  /**
   * Static initializer for a UIDNAInfo struct.
   * @stable 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
   * @stable ICU 4.6
   */
  U_STABLE 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
   * @stable ICU 4.6
   */
  U_STABLE 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
   * @stable ICU 4.6
   */
  U_STABLE 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
   * @stable ICU 4.6
   */
  U_STABLE 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
   * @stable ICU 4.6
   */
  U_STABLE 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
   * @stable ICU 4.6
   */
  U_STABLE 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
   * @stable ICU 4.6
   */
  U_STABLE 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
   * @stable ICU 4.6
   */
  U_STABLE 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.
       * @stable 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.
       * @stable 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.
       * @stable ICU 4.6
       */
      UIDNA_ERROR_DOMAIN_NAME_TOO_LONG=4,
      /**
       * A label starts with a hyphen-minus ('-').
       * @stable ICU 4.6
       */
      UIDNA_ERROR_LEADING_HYPHEN=8,
      /**
       * A label ends with a hyphen-minus ('-').
       * @stable ICU 4.6
       */
      UIDNA_ERROR_TRAILING_HYPHEN=0x10,
      /**
       * A label contains hyphen-minus ('-') in the third and fourth positions.
       * @stable ICU 4.6
       */
      UIDNA_ERROR_HYPHEN_3_4=0x20,
      /**
       * A label starts with a combining mark.
       * @stable ICU 4.6
       */
      UIDNA_ERROR_LEADING_COMBINING_MARK=0x40,
      /**
       * A label or domain name contains disallowed characters.
       * @stable 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.
       * @stable 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.
       * @stable 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.
       * @stable ICU 4.6
       */
      UIDNA_ERROR_INVALID_ACE_LABEL=0x400,
      /**
       * A label does not meet the IDNA BiDi requirements (for right-to-left characters).
       * @stable ICU 4.6
       */
      UIDNA_ERROR_BIDI=0x800,
      /**
       * A label does not meet the IDNA CONTEXTJ requirements.
       * @stable ICU 4.6
       */
      UIDNA_ERROR_CONTEXTJ=0x1000,
      /**
       * 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_PUNCTUATION=0x2000,
      /**
       * 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
       */
      UIDNA_ERROR_CONTEXTO_DIGITS=0x4000
  };
  
  #ifndef U_HIDE_DEPRECATED_API
  
  /* 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.
   * @deprecated ICU 55 Use UTS #46 instead via uidna_openUTS46() or class IDNA.
   */
  #if 0
  // Function is hidden because it is not a stable API.
  U_DEPRECATED int32_t U_EXPORT2
  uidna_toASCII(const UChar* src, int32_t srcLength, 
                UChar* dest, int32_t destCapacity,
                int32_t options,
                UParseError* parseError,
                UErrorCode* status);
  #endif
  
  
  /**
   * 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.
   * @deprecated ICU 55 Use UTS #46 instead via uidna_openUTS46() or class IDNA.
   */
  #if 0
  // Function is hidden because it is not a stable API.
  U_DEPRECATED int32_t U_EXPORT2
  uidna_toUnicode(const UChar* src, int32_t srcLength,
                  UChar* dest, int32_t destCapacity,
                  int32_t options,
                  UParseError* parseError,
                  UErrorCode* status);
  #endif
  
  
  /**
   * 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.
   * @deprecated ICU 55 Use UTS #46 instead via uidna_openUTS46() or class IDNA.
   */
  #if 0
  // Function is hidden because it is not a stable API.
  U_DEPRECATED int32_t U_EXPORT2
  uidna_IDNToASCII(  const UChar* src, int32_t srcLength,
                     UChar* dest, int32_t destCapacity,
                     int32_t options,
                     UParseError* parseError,
                     UErrorCode* status);
  #endif
  
  /**
   * 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.
   * @deprecated ICU 55 Use UTS #46 instead via uidna_openUTS46() or class IDNA.
   */
  #if 0
  // Function is hidden because it is not a stable API.
  U_DEPRECATED int32_t U_EXPORT2
  uidna_IDNToUnicode(  const UChar* src, int32_t srcLength,
                       UChar* dest, int32_t destCapacity,
                       int32_t options,
                       UParseError* parseError,
                       UErrorCode* status);
  #endif
  
  /**
   * 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
   * @deprecated ICU 55 Use UTS #46 instead via uidna_openUTS46() or class IDNA.
   */
  #if 0
  // Function is hidden because it is not a stable API.
  U_DEPRECATED int32_t U_EXPORT2
  uidna_compare(  const UChar *s1, int32_t length1,
                  const UChar *s2, int32_t length2,
                  int32_t options,
                  UErrorCode* status);
  #endif
  
  #endif  /* U_HIDE_DEPRECATED_API */
  
  #endif /* #if !UCONFIG_NO_IDNA */
  
  #endif
  