tor-browser

uspoof.h (81921B)

---

// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
***************************************************************************
* Copyright (C) 2008-2016, International Business Machines Corporation
* and others. All Rights Reserved.
***************************************************************************
*   file name:  uspoof.h
*   encoding:   UTF-8
*   tab size:   8 (not used)
*   indentation:4
*
*   created on: 2008Feb13
*   created by: Andy Heninger
*
*   Unicode Spoof Detection
*/

#ifndef USPOOF_H
#define USPOOF_H

#include "unicode/ubidi.h"
#include "unicode/utypes.h"
#include "unicode/uset.h"
#include "unicode/parseerr.h"

#if !UCONFIG_NO_NORMALIZATION


#if U_SHOW_CPLUSPLUS_API
#include "unicode/localpointer.h"
#include "unicode/unistr.h"
#include "unicode/uniset.h"
#endif


/**
* \file
* \brief C API: Unicode Security and Spoofing Detection
*
* <p>
* This class, based on <a href="http://unicode.org/reports/tr36">Unicode Technical Report #36</a> and
* <a href="http://unicode.org/reports/tr39">Unicode Technical Standard #39</a>, has two main functions:
*
* <ol>
* <li>Checking whether two strings are visually <em>confusable</em> with each other, such as "Harvest" and
* &quot;&Eta;arvest&quot;, where the second string starts with the Greek capital letter Eta.</li>
* <li>Checking whether an individual string is likely to be an attempt at confusing the reader (<em>spoof
* detection</em>), such as "paypal" with some Latin characters substituted with Cyrillic look-alikes.</li>
* </ol>
*
* <p>
* Although originally designed as a method for flagging suspicious identifier strings such as URLs,
* <code>USpoofChecker</code> has a number of other practical use cases, such as preventing attempts to evade bad-word
* content filters.
*
* <p>
* The functions of this class are exposed as C API, with a handful of syntactical conveniences for C++.
*
* <h2>Confusables</h2>
*
* <p>
* The following example shows how to use <code>USpoofChecker</code> to check for confusability between two strings:
*
* \code{.c}
* UErrorCode status = U_ZERO_ERROR;
* UChar* str1 = (UChar*) u"Harvest";
* UChar* str2 = (UChar*) u"\u0397arvest";  // with U+0397 GREEK CAPITAL LETTER ETA
*
* USpoofChecker* sc = uspoof_open(&status);
* uspoof_setChecks(sc, USPOOF_CONFUSABLE, &status);
*
* int32_t bitmask = uspoof_areConfusable(sc, str1, -1, str2, -1, &status);
* UBool result = bitmask != 0;
* // areConfusable: 1 (status: U_ZERO_ERROR)
* printf("areConfusable: %d (status: %s)\n", result, u_errorName(status));
* uspoof_close(sc);
* \endcode
*
* <p>
* The call to {@link uspoof_open} creates a <code>USpoofChecker</code> object; the call to {@link uspoof_setChecks}
* enables confusable checking and disables all other checks; the call to {@link uspoof_areConfusable} performs the
* confusability test; and the following line extracts the result out of the return value. For best performance,
* the instance should be created once (e.g., upon application startup), and the efficient
* {@link uspoof_areConfusable} method can be used at runtime.
*
* If the paragraph direction used to display the strings is known, the bidi function should be used instead:
*
* \code{.c}
* UErrorCode status = U_ZERO_ERROR;
* // These strings look identical when rendered in a left-to-right context.
* // They look distinct in a right-to-left context.
* UChar* str1 = (UChar*) u"A1\u05D0";  // A1א
* UChar* str2 = (UChar*) u"A\u05D01";  // Aא1
*
* USpoofChecker* sc = uspoof_open(&status);
* uspoof_setChecks(sc, USPOOF_CONFUSABLE, &status);
*
* int32_t bitmask = uspoof_areBidiConfusable(sc, UBIDI_LTR, str1, -1, str2, -1, &status);
* UBool result = bitmask != 0;
* // areBidiConfusable: 1 (status: U_ZERO_ERROR)
* printf("areBidiConfusable: %d (status: %s)\n", result, u_errorName(status));
* uspoof_close(sc);
* \endcode
*
* <p>
* The type {@link LocalUSpoofCheckerPointer} is exposed for C++ programmers.  It will automatically call
* {@link uspoof_close} when the object goes out of scope:
*
* \code{.cpp}
* UErrorCode status = U_ZERO_ERROR;
* LocalUSpoofCheckerPointer sc(uspoof_open(&status));
* uspoof_setChecks(sc.getAlias(), USPOOF_CONFUSABLE, &status);
* // ...
* \endcode
*
* UTS 39 defines two strings to be <em>confusable</em> if they map to the same <em>skeleton string</em>. A skeleton can
* be thought of as a "hash code". {@link uspoof_getSkeleton} computes the skeleton for a particular string, so
* the following snippet is equivalent to the example above:
*
* \code{.c}
* UErrorCode status = U_ZERO_ERROR;
* UChar* str1 = (UChar*) u"Harvest";
* UChar* str2 = (UChar*) u"\u0397arvest";  // with U+0397 GREEK CAPITAL LETTER ETA
*
* USpoofChecker* sc = uspoof_open(&status);
* uspoof_setChecks(sc, USPOOF_CONFUSABLE, &status);
*
* // Get skeleton 1
* int32_t skel1Len = uspoof_getSkeleton(sc, 0, str1, -1, NULL, 0, &status);
* UChar* skel1 = (UChar*) malloc(++skel1Len * sizeof(UChar));
* status = U_ZERO_ERROR;
* uspoof_getSkeleton(sc, 0, str1, -1, skel1, skel1Len, &status);
*
* // Get skeleton 2
* int32_t skel2Len = uspoof_getSkeleton(sc, 0, str2, -1, NULL, 0, &status);
* UChar* skel2 = (UChar*) malloc(++skel2Len * sizeof(UChar));
* status = U_ZERO_ERROR;
* uspoof_getSkeleton(sc, 0, str2, -1, skel2, skel2Len, &status);
*
* // Are the skeletons the same?
* UBool result = u_strcmp(skel1, skel2) == 0;
* // areConfusable: 1 (status: U_ZERO_ERROR)
* printf("areConfusable: %d (status: %s)\n", result, u_errorName(status));
* uspoof_close(sc);
* free(skel1);
* free(skel2);
* \endcode
*
* If you need to check if a string is confusable with any string in a dictionary of many strings, rather than calling
* {@link uspoof_areConfusable} many times in a loop, {@link uspoof_getSkeleton} can be used instead, as shown below:
*
* \code{.c}
* UErrorCode status = U_ZERO_ERROR;
* #define DICTIONARY_LENGTH 2
* UChar* dictionary[DICTIONARY_LENGTH] = { (UChar*) u"lorem", (UChar*) u"ipsum" };
* UChar* skeletons[DICTIONARY_LENGTH];
* UChar* str = (UChar*) u"1orern";
*
* // Setup:
* USpoofChecker* sc = uspoof_open(&status);
* uspoof_setChecks(sc, USPOOF_CONFUSABLE, &status);
* for (size_t i=0; i<DICTIONARY_LENGTH; i++) {
*     UChar* word = dictionary[i];
*     int32_t len = uspoof_getSkeleton(sc, 0, word, -1, NULL, 0, &status);
*     skeletons[i] = (UChar*) malloc(++len * sizeof(UChar));
*     status = U_ZERO_ERROR;
*     uspoof_getSkeleton(sc, 0, word, -1, skeletons[i], len, &status);
* }
*
* // Live Check:
* {
*     int32_t len = uspoof_getSkeleton(sc, 0, str, -1, NULL, 0, &status);
*     UChar* skel = (UChar*) malloc(++len * sizeof(UChar));
*     status = U_ZERO_ERROR;
*     uspoof_getSkeleton(sc, 0, str, -1, skel, len, &status);
*     UBool result = false;
*     for (size_t i=0; i<DICTIONARY_LENGTH; i++) {
*         result = u_strcmp(skel, skeletons[i]) == 0;
*         if (result == true) { break; }
*     }
*     // Has confusable in dictionary: 1 (status: U_ZERO_ERROR)
*     printf("Has confusable in dictionary: %d (status: %s)\n", result, u_errorName(status));
*     free(skel);
* }
*
* for (size_t i=0; i<DICTIONARY_LENGTH; i++) {
*     free(skeletons[i]);
* }
* uspoof_close(sc);
* \endcode
*
* <b>Note:</b> Since the Unicode confusables mapping table is frequently updated, confusable skeletons are <em>not</em>
* guaranteed to be the same between ICU releases. We therefore recommend that you always compute confusable skeletons
* at runtime and do not rely on creating a permanent, or difficult to update, database of skeletons.
*
* <h2>Spoof Detection</h2>
*
* The following snippet shows a minimal example of using <code>USpoofChecker</code> to perform spoof detection on a
* string:
*
* \code{.c}
* UErrorCode status = U_ZERO_ERROR;
* UChar* str = (UChar*) u"p\u0430ypal";  // with U+0430 CYRILLIC SMALL LETTER A
*
* // Get the default set of allowable characters:
* USet* allowed = uset_openEmpty();
* uset_addAll(allowed, uspoof_getRecommendedSet(&status));
* uset_addAll(allowed, uspoof_getInclusionSet(&status));
*
* USpoofChecker* sc = uspoof_open(&status);
* uspoof_setAllowedChars(sc, allowed, &status);
* uspoof_setRestrictionLevel(sc, USPOOF_MODERATELY_RESTRICTIVE);
*
* int32_t bitmask = uspoof_check(sc, str, -1, NULL, &status);
* UBool result = bitmask != 0;
* // fails checks: 1 (status: U_ZERO_ERROR)
* printf("fails checks: %d (status: %s)\n", result, u_errorName(status));
* uspoof_close(sc);
* uset_close(allowed);
* \endcode
*
* As in the case for confusability checking, it is good practice to create one <code>USpoofChecker</code> instance at
* startup, and call the cheaper {@link uspoof_check} online. We specify the set of
* allowed characters to be those with type RECOMMENDED or INCLUSION, according to the recommendation in UTS 39.
*
* In addition to {@link uspoof_check}, the function {@link uspoof_checkUTF8} is exposed for UTF8-encoded char* strings,
* and {@link uspoof_checkUnicodeString} is exposed for C++ programmers.
*
* If the {@link USPOOF_AUX_INFO} check is enabled, a limited amount of information on why a string failed the checks
* is available in the returned bitmask.  For complete information, use the {@link uspoof_check2} class of functions
* with a {@link USpoofCheckResult} parameter:
*
* \code{.c}
* UErrorCode status = U_ZERO_ERROR;
* UChar* str = (UChar*) u"p\u0430ypal";  // with U+0430 CYRILLIC SMALL LETTER A
*
* // Get the default set of allowable characters:
* USet* allowed = uset_openEmpty();
* uset_addAll(allowed, uspoof_getRecommendedSet(&status));
* uset_addAll(allowed, uspoof_getInclusionSet(&status));
*
* USpoofChecker* sc = uspoof_open(&status);
* uspoof_setAllowedChars(sc, allowed, &status);
* uspoof_setRestrictionLevel(sc, USPOOF_MODERATELY_RESTRICTIVE);
*
* USpoofCheckResult* checkResult = uspoof_openCheckResult(&status);
* int32_t bitmask = uspoof_check2(sc, str, -1, checkResult, &status);
*
* int32_t failures1 = bitmask;
* int32_t failures2 = uspoof_getCheckResultChecks(checkResult, &status);
* assert(failures1 == failures2);
* // checks that failed: 0x00000010 (status: U_ZERO_ERROR)
* printf("checks that failed: %#010x (status: %s)\n", failures1, u_errorName(status));
*
* // Cleanup:
* uspoof_close(sc);
* uset_close(allowed);
* uspoof_closeCheckResult(checkResult);
* \endcode
*
* C++ users can take advantage of a few syntactical conveniences.  The following snippet is functionally
* equivalent to the one above:
*
* \code{.cpp}
* UErrorCode status = U_ZERO_ERROR;
* UnicodeString str((UChar*) u"p\u0430ypal");  // with U+0430 CYRILLIC SMALL LETTER A
*
* // Get the default set of allowable characters:
* UnicodeSet allowed;
* allowed.addAll(*uspoof_getRecommendedUnicodeSet(&status));
* allowed.addAll(*uspoof_getInclusionUnicodeSet(&status));
*
* LocalUSpoofCheckerPointer sc(uspoof_open(&status));
* uspoof_setAllowedChars(sc.getAlias(), allowed.toUSet(), &status);
* uspoof_setRestrictionLevel(sc.getAlias(), USPOOF_MODERATELY_RESTRICTIVE);
*
* LocalUSpoofCheckResultPointer checkResult(uspoof_openCheckResult(&status));
* int32_t bitmask = uspoof_check2UnicodeString(sc.getAlias(), str, checkResult.getAlias(), &status);
*
* int32_t failures1 = bitmask;
* int32_t failures2 = uspoof_getCheckResultChecks(checkResult.getAlias(), &status);
* assert(failures1 == failures2);
* // checks that failed: 0x00000010 (status: U_ZERO_ERROR)
* printf("checks that failed: %#010x (status: %s)\n", failures1, u_errorName(status));
*
* // Explicit cleanup not necessary.
* \endcode
*
* The return value is a bitmask of the checks that failed. In this case, there was one check that failed:
* {@link USPOOF_RESTRICTION_LEVEL}, corresponding to the fifth bit (16). The possible checks are:
*
* <ul>
* <li><code>RESTRICTION_LEVEL</code>: flags strings that violate the
* <a href="http://unicode.org/reports/tr39/#Restriction_Level_Detection">Restriction Level</a> test as specified in UTS
* 39; in most cases, this means flagging strings that contain characters from multiple different scripts.</li>
* <li><code>INVISIBLE</code>: flags strings that contain invisible characters, such as zero-width spaces, or character
* sequences that are likely not to display, such as multiple occurrences of the same non-spacing mark.</li>
* <li><code>CHAR_LIMIT</code>: flags strings that contain characters outside of a specified set of acceptable
* characters. See {@link uspoof_setAllowedChars} and {@link uspoof_setAllowedLocales}.</li>
* <li><code>MIXED_NUMBERS</code>: flags strings that contain digits from multiple different numbering systems.</li>
* </ul>
*
* <p>
* These checks can be enabled independently of each other. For example, if you were interested in checking for only the
* INVISIBLE and MIXED_NUMBERS conditions, you could do:
*
* \code{.c}
* UErrorCode status = U_ZERO_ERROR;
* UChar* str = (UChar*) u"8\u09EA";  // 8 mixed with U+09EA BENGALI DIGIT FOUR
*
* USpoofChecker* sc = uspoof_open(&status);
* uspoof_setChecks(sc, USPOOF_INVISIBLE | USPOOF_MIXED_NUMBERS, &status);
*
* int32_t bitmask = uspoof_check2(sc, str, -1, NULL, &status);
* UBool result = bitmask != 0;
* // fails checks: 1 (status: U_ZERO_ERROR)
* printf("fails checks: %d (status: %s)\n", result, u_errorName(status));
* uspoof_close(sc);
* \endcode
*
* Here is an example in C++ showing how to compute the restriction level of a string:
*
* \code{.cpp}
* UErrorCode status = U_ZERO_ERROR;
* UnicodeString str((UChar*) u"p\u0430ypal");  // with U+0430 CYRILLIC SMALL LETTER A
*
* // Get the default set of allowable characters:
* UnicodeSet allowed;
* allowed.addAll(*uspoof_getRecommendedUnicodeSet(&status));
* allowed.addAll(*uspoof_getInclusionUnicodeSet(&status));
*
* LocalUSpoofCheckerPointer sc(uspoof_open(&status));
* uspoof_setAllowedChars(sc.getAlias(), allowed.toUSet(), &status);
* uspoof_setRestrictionLevel(sc.getAlias(), USPOOF_MODERATELY_RESTRICTIVE);
* uspoof_setChecks(sc.getAlias(), USPOOF_RESTRICTION_LEVEL | USPOOF_AUX_INFO, &status);
*
* LocalUSpoofCheckResultPointer checkResult(uspoof_openCheckResult(&status));
* int32_t bitmask = uspoof_check2UnicodeString(sc.getAlias(), str, checkResult.getAlias(), &status);
*
* URestrictionLevel restrictionLevel = uspoof_getCheckResultRestrictionLevel(checkResult.getAlias(), &status);
* // Since USPOOF_AUX_INFO was enabled, the restriction level is also available in the upper bits of the bitmask:
* assert((restrictionLevel & bitmask) == restrictionLevel);
* // Restriction level: 0x50000000 (status: U_ZERO_ERROR)
* printf("Restriction level: %#010x (status: %s)\n", restrictionLevel, u_errorName(status));
* \endcode
*
* The code '0x50000000' corresponds to the restriction level USPOOF_MINIMALLY_RESTRICTIVE.  Since
* USPOOF_MINIMALLY_RESTRICTIVE is weaker than USPOOF_MODERATELY_RESTRICTIVE, the string fails the check.
*
* <b>Note:</b> The Restriction Level is the most powerful of the checks. The full logic is documented in
* <a href="http://unicode.org/reports/tr39/#Restriction_Level_Detection">UTS 39</a>, but the basic idea is that strings
* are restricted to contain characters from only a single script, <em>except</em> that most scripts are allowed to have
* Latin characters interspersed. Although the default restriction level is <code>HIGHLY_RESTRICTIVE</code>, it is
* recommended that users set their restriction level to <code>MODERATELY_RESTRICTIVE</code>, which allows Latin mixed
* with all other scripts except Cyrillic, Greek, and Cherokee, with which it is often confusable. For more details on
* the levels, see UTS 39 or {@link URestrictionLevel}. The Restriction Level test is aware of the set of
* allowed characters set in {@link uspoof_setAllowedChars}. Note that characters which have script code
* COMMON or INHERITED, such as numbers and punctuation, are ignored when computing whether a string has multiple
* scripts.
*
* <h2>Advanced bidirectional usage</h2>
* If the paragraph direction with which the identifiers will be displayed is not known, there are
* multiple options for confusable detection depending on the circumstances.
*
* <p>
* In some circumstances, the only concern is confusion between identifiers displayed with the same
* paragraph direction.
*
* <p>
* An example is the case where identifiers are usernames prefixed with the @ symbol.
* That symbol will appear to the left in a left-to-right context, and to the right in a
* right-to-left context, so that an identifier displayed in a left-to-right context can never be
* confused with an identifier displayed in a right-to-left context:
* <ul>
* <li>
* The usernames "A1א" (A one aleph) and "Aא1" (A aleph 1)
* would be considered confusable, since they both appear as \@A1א in a left-to-right context, and the
* usernames "אA_1" (aleph A underscore one) and "א1_A" (aleph one underscore A) would be considered
* confusable, since they both appear as A_1א@ in a right-to-left context.
* </li>
* <li>
* The username "Mark_" would not be considered confusable with the username "_Mark",
* even though the latter would appear as Mark_@ in a right-to-left context, and the
* former as \@Mark_ in a left-to-right context.
* </li>
* </ul>
* <p>
* In that case, the caller should check for both LTR-confusability and RTL-confusability:
*
* \code{.cpp}
* bool confusableInEitherDirection =
*     uspoof_areBidiConfusableUnicodeString(sc, UBIDI_LTR, id1, id2, &status) ||
*     uspoof_areBidiConfusableUnicodeString(sc, UBIDI_RTL, id1, id2, &status);
* \endcode
*
* If the bidiSkeleton is used, the LTR and RTL skeleta should be kept separately and compared, LTR
* with LTR and RTL with RTL.
*
* <p>
* In cases where confusability between the visual appearances of an identifier displayed in a
* left-to-right context with another identifier displayed in a right-to-left context is a concern,
* the LTR skeleton of one can be compared with the RTL skeleton of the other.  However, this
* very broad definition of confusability may have unexpected results; for instance, it treats the
* ASCII identifiers "Mark_" and "_Mark" as confusable.
*
* <h2>Additional Information</h2>
*
* A <code>USpoofChecker</code> instance may be used repeatedly to perform checks on any number of identifiers.
*
* <b>Thread Safety:</b> The test functions for checking a single identifier, or for testing whether
* two identifiers are possible confusable, are thread safe. They may called concurrently, from multiple threads,
* using the same USpoofChecker instance.
*
* More generally, the standard ICU thread safety rules apply: functions that take a const USpoofChecker parameter are
* thread safe. Those that take a non-const USpoofChecker are not thread safe..
*
* @stable ICU 4.6
*/

U_CDECL_BEGIN

struct USpoofChecker;
/**
* @stable ICU 4.2
*/
typedef struct USpoofChecker USpoofChecker; /**< typedef for C of USpoofChecker */

struct USpoofCheckResult;
/**
* @see uspoof_openCheckResult
* @stable ICU 58
*/
typedef struct USpoofCheckResult USpoofCheckResult;

/**
* Enum for the kinds of checks that USpoofChecker can perform.
* These enum values are used both to select the set of checks that
* will be performed, and to report results from the check function.
*
* @stable ICU 4.2
*/
typedef enum USpoofChecks {
   /**
    * When performing the two-string {@link uspoof_areConfusable} test, this flag in the return value indicates
    * that the two strings are visually confusable and that they are from the same script, according to UTS 39 section
    * 4.
    *
    * @see uspoof_areConfusable
    * @stable ICU 4.2
    */
   USPOOF_SINGLE_SCRIPT_CONFUSABLE =   1,

   /**
    * When performing the two-string {@link uspoof_areConfusable} test, this flag in the return value indicates
    * that the two strings are visually confusable and that they are <b>not</b> from the same script, according to UTS
    * 39 section 4.
    *
    * @see uspoof_areConfusable
    * @stable ICU 4.2
    */
   USPOOF_MIXED_SCRIPT_CONFUSABLE  =   2,

   /**
    * When performing the two-string {@link uspoof_areConfusable} test, this flag in the return value indicates
    * that the two strings are visually confusable and that they are not from the same script but both of them are
    * single-script strings, according to UTS 39 section 4.
    *
    * @see uspoof_areConfusable
    * @stable ICU 4.2
    */
   USPOOF_WHOLE_SCRIPT_CONFUSABLE  =   4,

   /**
    * Enable this flag in {@link uspoof_setChecks} to turn on all types of confusables.  You may set
    * the checks to some subset of SINGLE_SCRIPT_CONFUSABLE, MIXED_SCRIPT_CONFUSABLE, or WHOLE_SCRIPT_CONFUSABLE to
    * make {@link uspoof_areConfusable} return only those types of confusables.
    *
    * @see uspoof_areConfusable
    * @see uspoof_getSkeleton
    * @stable ICU 58
    */
   USPOOF_CONFUSABLE               =   USPOOF_SINGLE_SCRIPT_CONFUSABLE | USPOOF_MIXED_SCRIPT_CONFUSABLE | USPOOF_WHOLE_SCRIPT_CONFUSABLE,

#ifndef U_HIDE_DEPRECATED_API
   /**
     * This flag is deprecated and no longer affects the behavior of SpoofChecker.
     *
     * @deprecated ICU 58  Any case confusable mappings were removed from UTS 39; the corresponding ICU API was deprecated.
     */
   USPOOF_ANY_CASE                 =   8,
#endif  /* U_HIDE_DEPRECATED_API */

   /**
     * Check that an identifier is no looser than the specified RestrictionLevel.
     * The default if {@link uspoof_setRestrictionLevel} is not called is HIGHLY_RESTRICTIVE.
     *
     * If USPOOF_AUX_INFO is enabled the actual restriction level of the
     * identifier being tested will also be returned by uspoof_check().
     *
     * @see URestrictionLevel
     * @see uspoof_setRestrictionLevel
     * @see USPOOF_AUX_INFO
     *
     * @stable ICU 51
     */
   USPOOF_RESTRICTION_LEVEL        = 16,

#ifndef U_HIDE_DEPRECATED_API
   /** Check that an identifier contains only characters from a
     * single script (plus chars from the common and inherited scripts.)
     * Applies to checks of a single identifier check only.
     * @deprecated ICU 51  Use RESTRICTION_LEVEL instead.
     */
   USPOOF_SINGLE_SCRIPT            =  USPOOF_RESTRICTION_LEVEL,
#endif  /* U_HIDE_DEPRECATED_API */

   /** Check an identifier for the presence of invisible characters,
     * such as zero-width spaces, or character sequences that are
     * likely not to display, such as multiple occurrences of the same
     * non-spacing mark.  This check does not test the input string as a whole
     * for conformance to any particular syntax for identifiers.
     */
   USPOOF_INVISIBLE                =  32,

   /** Check that an identifier contains only characters from a specified set
     * of acceptable characters.  See {@link uspoof_setAllowedChars} and
     * {@link uspoof_setAllowedLocales}.  Note that a string that fails this check
     * will also fail the {@link USPOOF_RESTRICTION_LEVEL} check.
     */
   USPOOF_CHAR_LIMIT               =  64,

   /**
    * Check that an identifier does not mix numbers from different numbering systems.
    * For more information, see UTS 39 section 5.3.
    *
    * @stable ICU 51
    */
   USPOOF_MIXED_NUMBERS            = 128,

   /**
    * Check that an identifier does not have a combining character following a character in which that
    * combining character would be hidden; for example 'i' followed by a U+0307 combining dot.
    *
    * More specifically, the following characters are forbidden from preceding a U+0307:
    * <ul>
    * <li>Those with the Soft_Dotted Unicode property (which includes 'i' and 'j')</li>
    * <li>Latin lowercase letter 'l'</li>
    * <li>Dotless 'i' and 'j' ('ı' and 'ȷ', U+0131 and U+0237)</li>
    * <li>Any character whose confusable prototype ends with such a character
    * (Soft_Dotted, 'l', 'ı', or 'ȷ')</li>
    * </ul>
    * In addition, combining characters are allowed between the above characters and U+0307 except those
    * with combining class 0 or combining class "Above" (230, same class as U+0307).
    *
    * This list and the number of combing characters considered by this check may grow over time.
    *
    * @stable ICU 62
    */
   USPOOF_HIDDEN_OVERLAY            = 256,

  /**
    * Enable all spoof checks.
    *
    * @stable ICU 4.6
    */
   USPOOF_ALL_CHECKS               = 0xFFFF,

   /**
     * Enable the return of auxiliary (non-error) information in the
     * upper bits of the check results value.
     *
     * If this "check" is not enabled, the results of {@link uspoof_check} will be
     * zero when an identifier passes all of the enabled checks.
     *
     * If this "check" is enabled, (uspoof_check() & {@link USPOOF_ALL_CHECKS}) will
     * be zero when an identifier passes all checks.
     *
     * @stable ICU 51
     */
   USPOOF_AUX_INFO                  = 0x40000000

   } USpoofChecks;


   /**
    * Constants from UTS #39 for use in {@link uspoof_setRestrictionLevel}, and
    * for returned identifier restriction levels in check results.
    *
    * @stable ICU 51
    *
    * @see uspoof_setRestrictionLevel
    * @see uspoof_check
    */
   typedef enum URestrictionLevel {
       /**
        * All characters in the string are in the identifier profile and all characters in the string are in the
        * ASCII range.
        *
        * @stable ICU 51
        */
       USPOOF_ASCII = 0x10000000,
       /**
        * The string classifies as ASCII-Only, or all characters in the string are in the identifier profile and
        * the string is single-script, according to the definition in UTS 39 section 5.1.
        *
        * @stable ICU 53
        */
       USPOOF_SINGLE_SCRIPT_RESTRICTIVE = 0x20000000,
       /**
        * The string classifies as Single Script, or all characters in the string are in the identifier profile and
        * the string is covered by any of the following sets of scripts, according to the definition in UTS 39
        * section 5.1:
        * <ul>
        *   <li>Latin + Han + Bopomofo (or equivalently: Latn + Hanb)</li>
        *   <li>Latin + Han + Hiragana + Katakana (or equivalently: Latn + Jpan)</li>
        *   <li>Latin + Han + Hangul (or equivalently: Latn +Kore)</li>
        * </ul>
        * This is the default restriction in ICU.
        *
        * @stable ICU 51
        */
       USPOOF_HIGHLY_RESTRICTIVE = 0x30000000,
       /**
        * The string classifies as Highly Restrictive, or all characters in the string are in the identifier profile
        * and the string is covered by Latin and any one other Recommended or Aspirational script, except Cyrillic,
        * Greek, and Cherokee.
        *
        * @stable ICU 51
        */
       USPOOF_MODERATELY_RESTRICTIVE = 0x40000000,
       /**
        * All characters in the string are in the identifier profile.  Allow arbitrary mixtures of scripts.
        *
        * @stable ICU 51
        */
       USPOOF_MINIMALLY_RESTRICTIVE = 0x50000000,
       /**
        * Any valid identifiers, including characters outside of the Identifier Profile.
        *
        * @stable ICU 51
        */
       USPOOF_UNRESTRICTIVE = 0x60000000,
       /**
        * Mask for selecting the Restriction Level bits from the return value of {@link uspoof_check}.
        *
        * @stable ICU 53
        */
       USPOOF_RESTRICTION_LEVEL_MASK = 0x7F000000,
#ifndef U_HIDE_INTERNAL_API
       /**
        * An undefined restriction level.
        * @internal
        */
       USPOOF_UNDEFINED_RESTRICTIVE = -1
#endif  /* U_HIDE_INTERNAL_API */
   } URestrictionLevel;

/**
*  Create a Unicode Spoof Checker, configured to perform all
*  checks except for USPOOF_LOCALE_LIMIT and USPOOF_CHAR_LIMIT.
*  Note that additional checks may be added in the future,
*  resulting in the changes to the default checking behavior.
*
*  @param status  The error code, set if this function encounters a problem.
*  @return        the newly created Spoof Checker
*  @stable ICU 4.2
*/
U_CAPI USpoofChecker * U_EXPORT2
uspoof_open(UErrorCode *status);


/**
* Open a Spoof checker from its serialized form, stored in 32-bit-aligned memory.
* Inverse of uspoof_serialize().
* The memory containing the serialized data must remain valid and unchanged
* as long as the spoof checker, or any cloned copies of the spoof checker,
* are in use.  Ownership of the memory remains with the caller.
* The spoof checker (and any clones) must be closed prior to deleting the
* serialized data.
*
* @param data a pointer to 32-bit-aligned memory containing the serialized form of spoof data
* @param length the number of bytes available at data;
*               can be more than necessary
* @param pActualLength receives the actual number of bytes at data taken up by the data;
*                      can be NULL
* @param pErrorCode ICU error code
* @return the spoof checker.
*
* @see uspoof_open
* @see uspoof_serialize
* @stable ICU 4.2
*/
U_CAPI USpoofChecker * U_EXPORT2
uspoof_openFromSerialized(const void *data, int32_t length, int32_t *pActualLength,
                         UErrorCode *pErrorCode);

/**
 * Open a Spoof Checker from the source form of the spoof data.
 * The input corresponds to the Unicode data file confusables.txt
 * as described in Unicode Technical Standard #39.  The syntax of the source data
 * is as described in UTS #39 for this file, and the content of
 * this file is acceptable input.
 *
 * The character encoding of the (char *) input text is UTF-8.
 *
 * @param confusables a pointer to the confusable characters definitions,
 *                    as found in file confusables.txt from unicode.org.
 * @param confusablesLen The length of the confusables text, or -1 if the
 *                    input string is zero terminated.
 * @param confusablesWholeScript
 *                    Deprecated in ICU 58.  No longer used.
 * @param confusablesWholeScriptLen
 *                    Deprecated in ICU 58.  No longer used.
 * @param errType     In the event of an error in the input, indicates
 *                    which of the input files contains the error.
 *                    The value is one of USPOOF_SINGLE_SCRIPT_CONFUSABLE or
 *                    USPOOF_WHOLE_SCRIPT_CONFUSABLE, or
 *                    zero if no errors are found.
 * @param pe          In the event of an error in the input, receives the position
 *                    in the input text (line, offset) of the error.
 * @param status      an in/out ICU UErrorCode.  Among the possible errors is
 *                    U_PARSE_ERROR, which is used to report syntax errors
 *                    in the input.
 * @return            A spoof checker that uses the rules from the input files.
 * @stable ICU 4.2
 */
U_CAPI USpoofChecker * U_EXPORT2
uspoof_openFromSource(const char *confusables,  int32_t confusablesLen,
                     const char *confusablesWholeScript, int32_t confusablesWholeScriptLen,
                     int32_t *errType, UParseError *pe, UErrorCode *status);


/**
 * Close a Spoof Checker, freeing any memory that was being held by
 *   its implementation.
 * @stable ICU 4.2
 */
U_CAPI void U_EXPORT2
uspoof_close(USpoofChecker *sc);

/**
* Clone a Spoof Checker.  The clone will be set to perform the same checks
*   as the original source.
*
* @param sc       The source USpoofChecker
* @param status   The error code, set if this function encounters a problem.
* @return
* @stable ICU 4.2
*/
U_CAPI USpoofChecker * U_EXPORT2
uspoof_clone(const USpoofChecker *sc, UErrorCode *status);


/**
* Specify the bitmask of checks that will be performed by {@link uspoof_check}. Calling this method
* overwrites any checks that may have already been enabled. By default, all checks are enabled.
*
* To enable specific checks and disable all others,
* OR together only the bit constants for the desired checks.
* For example, to fail strings containing characters outside of
* the set specified by {@link uspoof_setAllowedChars} and
* also strings that contain digits from mixed numbering systems:
*
* <pre>
* {@code
* uspoof_setChecks(USPOOF_CHAR_LIMIT | USPOOF_MIXED_NUMBERS);
* }
* </pre>
*
* To disable specific checks and enable all others,
* start with ALL_CHECKS and "AND away" the not-desired checks.
* For example, if you are not planning to use the {@link uspoof_areConfusable} functionality,
* it is good practice to disable the CONFUSABLE check:
*
* <pre>
* {@code
* uspoof_setChecks(USPOOF_ALL_CHECKS & ~USPOOF_CONFUSABLE);
* }
* </pre>
*
* Note that methods such as {@link uspoof_setAllowedChars}, {@link uspoof_setAllowedLocales}, and
* {@link uspoof_setRestrictionLevel} will enable certain checks when called. Those methods will OR the check they
* enable onto the existing bitmask specified by this method. For more details, see the documentation of those
* methods.
*
* @param sc       The USpoofChecker
* @param checks         The set of checks that this spoof checker will perform.
*                 The value is a bit set, obtained by OR-ing together
*                 values from enum USpoofChecks.
* @param status   The error code, set if this function encounters a problem.
* @stable ICU 4.2
*
*/
U_CAPI void U_EXPORT2
uspoof_setChecks(USpoofChecker *sc, int32_t checks, UErrorCode *status);

/**
* Get the set of checks that this Spoof Checker has been configured to perform.
*
* @param sc       The USpoofChecker
* @param status   The error code, set if this function encounters a problem.
* @return         The set of checks that this spoof checker will perform.
*                 The value is a bit set, obtained by OR-ing together
*                 values from enum USpoofChecks.
* @stable ICU 4.2
*
*/
U_CAPI int32_t U_EXPORT2
uspoof_getChecks(const USpoofChecker *sc, UErrorCode *status);

/**
* Set the loosest restriction level allowed for strings. The default if this is not called is
* {@link USPOOF_HIGHLY_RESTRICTIVE}. Calling this method enables the {@link USPOOF_RESTRICTION_LEVEL} and
* {@link USPOOF_MIXED_NUMBERS} checks, corresponding to Sections 5.1 and 5.2 of UTS 39. To customize which checks are
* to be performed by {@link uspoof_check}, see {@link uspoof_setChecks}.
*
* @param sc       The USpoofChecker
* @param restrictionLevel The loosest restriction level allowed.
* @see URestrictionLevel
* @stable ICU 51
*/
U_CAPI void U_EXPORT2
uspoof_setRestrictionLevel(USpoofChecker *sc, URestrictionLevel restrictionLevel);


/**
 * Get the Restriction Level that will be tested if the checks include {@link USPOOF_RESTRICTION_LEVEL}.
 *
 * @return The restriction level
 * @see URestrictionLevel
 * @stable ICU 51
 */
U_CAPI URestrictionLevel U_EXPORT2
uspoof_getRestrictionLevel(const USpoofChecker *sc);

/**
* Limit characters that are acceptable in identifiers being checked to those
* normally used with the languages associated with the specified locales.
* Any previously specified list of locales is replaced by the new settings.
*
* A set of languages is determined from the locale(s), and
* from those a set of acceptable Unicode scripts is determined.
* Characters from this set of scripts, along with characters from
* the "common" and "inherited" Unicode Script categories
* will be permitted.
*
* Supplying an empty string removes all restrictions;
* characters from any script will be allowed.
*
* The {@link USPOOF_CHAR_LIMIT} test is automatically enabled for this
* USpoofChecker when calling this function with a non-empty list
* of locales.
*
* The Unicode Set of characters that will be allowed is accessible
* via the uspoof_getAllowedChars() function.  uspoof_setAllowedLocales()
* will <i>replace</i> any previously applied set of allowed characters.
*
* Adjustments, such as additions or deletions of certain classes of characters,
* can be made to the result of uspoof_setAllowedLocales() by
* fetching the resulting set with uspoof_getAllowedChars(),
* manipulating it with the Unicode Set API, then resetting the
* spoof detectors limits with uspoof_setAllowedChars().
*
* @param sc           The USpoofChecker
* @param localesList  A list list of locales, from which the language
*                     and associated script are extracted.  The locales
*                     are comma-separated if there is more than one.
*                     White space may not appear within an individual locale,
*                     but is ignored otherwise.
*                     The locales are syntactically like those from the
*                     HTTP Accept-Language header.
*                     If the localesList is empty, no restrictions will be placed on
*                     the allowed characters.
*
* @param status       The error code, set if this function encounters a problem.
* @stable ICU 4.2
*/
U_CAPI void U_EXPORT2
uspoof_setAllowedLocales(USpoofChecker *sc, const char *localesList, UErrorCode *status);

/**
* Get a list of locales for the scripts that are acceptable in strings
*  to be checked.  If no limitations on scripts have been specified,
*  an empty string will be returned.
*
*  uspoof_setAllowedChars() will reset the list of allowed to be empty.
*
*  The format of the returned list is the same as that supplied to
*  uspoof_setAllowedLocales(), but returned list may not be identical
*  to the originally specified string; the string may be reformatted,
*  and information other than languages from
*  the originally specified locales may be omitted.
*
* @param sc           The USpoofChecker
* @param status       The error code, set if this function encounters a problem.
* @return             A string containing a list of  locales corresponding
*                     to the acceptable scripts, formatted like an
*                     HTTP Accept Language value.
*
* @stable ICU 4.2
*/
U_CAPI const char * U_EXPORT2
uspoof_getAllowedLocales(USpoofChecker *sc, UErrorCode *status);


/**
* Limit the acceptable characters to those specified by a Unicode Set.
*   Any previously specified character limit is
*   is replaced by the new settings.  This includes limits on
*   characters that were set with the uspoof_setAllowedLocales() function.
*
* The USPOOF_CHAR_LIMIT test is automatically enabled for this
* USpoofChecker by this function.
*
* @param sc       The USpoofChecker
* @param chars    A Unicode Set containing the list of
*                 characters that are permitted.  Ownership of the set
*                 remains with the caller.  The incoming set is cloned by
*                 this function, so there are no restrictions on modifying
*                 or deleting the USet after calling this function.
* @param status   The error code, set if this function encounters a problem.
* @stable ICU 4.2
*/
U_CAPI void U_EXPORT2
uspoof_setAllowedChars(USpoofChecker *sc, const USet *chars, UErrorCode *status);


/**
* Get a USet for the characters permitted in an identifier.
* This corresponds to the limits imposed by the Set Allowed Characters
* functions. Limitations imposed by other checks will not be
* reflected in the set returned by this function.
*
* The returned set will be frozen, meaning that it cannot be modified
* by the caller.
*
* Ownership of the returned set remains with the Spoof Detector.  The
* returned set will become invalid if the spoof detector is closed,
* or if a new set of allowed characters is specified.
*
*
* @param sc       The USpoofChecker
* @param status   The error code, set if this function encounters a problem.
* @return         A USet containing the characters that are permitted by
*                 the USPOOF_CHAR_LIMIT test.
* @stable ICU 4.2
*/
U_CAPI const USet * U_EXPORT2
uspoof_getAllowedChars(const USpoofChecker *sc, UErrorCode *status);


/**
* Check the specified string for possible security issues.
* The text to be checked will typically be an identifier of some sort.
* The set of checks to be performed is specified with uspoof_setChecks().
*
* \note
*   Consider using the newer API, {@link uspoof_check2}, instead.
*   The newer API exposes additional information from the check procedure
*   and is otherwise identical to this method.
*
* @param sc      The USpoofChecker
* @param id      The identifier to be checked for possible security issues,
*                in UTF-16 format.
* @param length  the length of the string to be checked, expressed in
*                16 bit UTF-16 code units, or -1 if the string is
*                zero terminated.
* @param position  Deprecated in ICU 51.  Always returns zero.
*                Originally, an out parameter for the index of the first
*                string position that failed a check.
*                This parameter may be NULL.
* @param status  The error code, set if an error occurred while attempting to
*                perform the check.
*                Spoofing or security issues detected with the input string are
*                not reported here, but through the function's return value.
* @return        An integer value with bits set for any potential security
*                or spoofing issues detected.  The bits are defined by
*                enum USpoofChecks.  (returned_value & USPOOF_ALL_CHECKS)
*                will be zero if the input string passes all of the
*                enabled checks.
* @see uspoof_check2
* @stable ICU 4.2
*/
U_CAPI int32_t U_EXPORT2
uspoof_check(const USpoofChecker *sc,
                        const UChar *id, int32_t length,
                        int32_t *position,
                        UErrorCode *status);


/**
* Check the specified string for possible security issues.
* The text to be checked will typically be an identifier of some sort.
* The set of checks to be performed is specified with uspoof_setChecks().
*
* \note
*   Consider using the newer API, {@link uspoof_check2UTF8}, instead.
*   The newer API exposes additional information from the check procedure
*   and is otherwise identical to this method.
*
* @param sc      The USpoofChecker
* @param id      A identifier to be checked for possible security issues, in UTF8 format.
* @param length  the length of the string to be checked, or -1 if the string is
*                zero terminated.
* @param position  Deprecated in ICU 51.  Always returns zero.
*                Originally, an out parameter for the index of the first
*                string position that failed a check.
*                This parameter may be NULL.
* @param status  The error code, set if an error occurred while attempting to
*                perform the check.
*                Spoofing or security issues detected with the input string are
*                not reported here, but through the function's return value.
*                If the input contains invalid UTF-8 sequences,
*                a status of U_INVALID_CHAR_FOUND will be returned.
* @return        An integer value with bits set for any potential security
*                or spoofing issues detected.  The bits are defined by
*                enum USpoofChecks.  (returned_value & USPOOF_ALL_CHECKS)
*                will be zero if the input string passes all of the
*                enabled checks.
* @see uspoof_check2UTF8
* @stable ICU 4.2
*/
U_CAPI int32_t U_EXPORT2
uspoof_checkUTF8(const USpoofChecker *sc,
                const char *id, int32_t length,
                int32_t *position,
                UErrorCode *status);


/**
* Check the specified string for possible security issues.
* The text to be checked will typically be an identifier of some sort.
* The set of checks to be performed is specified with uspoof_setChecks().
*
* @param sc      The USpoofChecker
* @param id      The identifier to be checked for possible security issues,
*                in UTF-16 format.
* @param length  the length of the string to be checked, or -1 if the string is
*                zero terminated.
* @param checkResult  An instance of USpoofCheckResult to be filled with
*                details about the identifier.  Can be NULL.
* @param status  The error code, set if an error occurred while attempting to
*                perform the check.
*                Spoofing or security issues detected with the input string are
*                not reported here, but through the function's return value.
* @return        An integer value with bits set for any potential security
*                or spoofing issues detected.  The bits are defined by
*                enum USpoofChecks.  (returned_value & USPOOF_ALL_CHECKS)
*                will be zero if the input string passes all of the
*                enabled checks.  Any information in this bitmask will be
*                consistent with the information saved in the optional
*                checkResult parameter.
* @see uspoof_openCheckResult
* @see uspoof_check2UTF8
* @see uspoof_check2UnicodeString
* @stable ICU 58
*/
U_CAPI int32_t U_EXPORT2
uspoof_check2(const USpoofChecker *sc,
   const UChar* id, int32_t length,
   USpoofCheckResult* checkResult,
   UErrorCode *status);

/**
* Check the specified string for possible security issues.
* The text to be checked will typically be an identifier of some sort.
* The set of checks to be performed is specified with uspoof_setChecks().
*
* This version of {@link uspoof_check} accepts a USpoofCheckResult, which
* returns additional information about the identifier.  For more
* information, see {@link uspoof_openCheckResult}.
*
* @param sc      The USpoofChecker
* @param id      A identifier to be checked for possible security issues, in UTF8 format.
* @param length  the length of the string to be checked, or -1 if the string is
*                zero terminated.
* @param checkResult  An instance of USpoofCheckResult to be filled with
*                details about the identifier.  Can be NULL.
* @param status  The error code, set if an error occurred while attempting to
*                perform the check.
*                Spoofing or security issues detected with the input string are
*                not reported here, but through the function's return value.
* @return        An integer value with bits set for any potential security
*                or spoofing issues detected.  The bits are defined by
*                enum USpoofChecks.  (returned_value & USPOOF_ALL_CHECKS)
*                will be zero if the input string passes all of the
*                enabled checks.  Any information in this bitmask will be
*                consistent with the information saved in the optional
*                checkResult parameter.
* @see uspoof_openCheckResult
* @see uspoof_check2
* @see uspoof_check2UnicodeString
* @stable ICU 58
*/
U_CAPI int32_t U_EXPORT2
uspoof_check2UTF8(const USpoofChecker *sc,
   const char *id, int32_t length,
   USpoofCheckResult* checkResult,
   UErrorCode *status);

/**
* Create a USpoofCheckResult, used by the {@link uspoof_check2} class of functions to return
* information about the identifier.  Information includes:
* <ul>
*   <li>A bitmask of the checks that failed</li>
*   <li>The identifier's restriction level (UTS 39 section 5.2)</li>
*   <li>The set of numerics in the string (UTS 39 section 5.3)</li>
* </ul>
* The data held in a USpoofCheckResult is cleared whenever it is passed into a new call
* of {@link uspoof_check2}.
*
* @param status  The error code, set if this function encounters a problem.
* @return        the newly created USpoofCheckResult
* @see uspoof_check2
* @see uspoof_check2UTF8
* @see uspoof_check2UnicodeString
* @stable ICU 58
*/
U_CAPI USpoofCheckResult* U_EXPORT2
uspoof_openCheckResult(UErrorCode *status);

/**
* Close a USpoofCheckResult, freeing any memory that was being held by
*   its implementation.
*
* @param checkResult  The instance of USpoofCheckResult to close
* @stable ICU 58
*/
U_CAPI void U_EXPORT2
uspoof_closeCheckResult(USpoofCheckResult *checkResult);

/**
* Indicates which of the spoof check(s) have failed. The value is a bitwise OR of the constants for the tests
* in question: USPOOF_RESTRICTION_LEVEL, USPOOF_CHAR_LIMIT, and so on.
*
* @param checkResult  The instance of USpoofCheckResult created by {@link uspoof_openCheckResult}
* @param status       The error code, set if an error occurred.
* @return        An integer value with bits set for any potential security
*                or spoofing issues detected.  The bits are defined by
*                enum USpoofChecks.  (returned_value & USPOOF_ALL_CHECKS)
*                will be zero if the input string passes all of the
*                enabled checks.
* @see uspoof_setChecks
* @stable ICU 58
*/
U_CAPI int32_t U_EXPORT2
uspoof_getCheckResultChecks(const USpoofCheckResult *checkResult, UErrorCode *status);

/**
* Gets the restriction level that the text meets, if the USPOOF_RESTRICTION_LEVEL check
* was enabled; otherwise, undefined.
*
* @param checkResult  The instance of USpoofCheckResult created by {@link uspoof_openCheckResult}
* @param status       The error code, set if an error occurred.
* @return             The restriction level contained in the USpoofCheckResult
* @see uspoof_setRestrictionLevel
* @stable ICU 58
*/
U_CAPI URestrictionLevel U_EXPORT2
uspoof_getCheckResultRestrictionLevel(const USpoofCheckResult *checkResult, UErrorCode *status);

/**
* Gets the set of numerics found in the string, if the USPOOF_MIXED_NUMBERS check was enabled;
* otherwise, undefined.  The set will contain the zero digit from each decimal number system found
* in the input string.  Ownership of the returned USet remains with the USpoofCheckResult.
* The USet will be free'd when {@link uspoof_closeCheckResult} is called.
*
* @param checkResult  The instance of USpoofCheckResult created by {@link uspoof_openCheckResult}
* @return             The set of numerics contained in the USpoofCheckResult
* @param status       The error code, set if an error occurred.
* @stable ICU 58
*/
U_CAPI const USet* U_EXPORT2
uspoof_getCheckResultNumerics(const USpoofCheckResult *checkResult, UErrorCode *status);


/**
* Check whether two specified strings are visually confusable.
*
* If the strings are confusable, the return value will be nonzero, as long as
* {@link USPOOF_CONFUSABLE} was enabled in uspoof_setChecks().
*
* The bits in the return value correspond to flags for each of the classes of
* confusables applicable to the two input strings.  According to UTS 39
* section 4, the possible flags are:
*
* <ul>
*   <li>{@link USPOOF_SINGLE_SCRIPT_CONFUSABLE}</li>
*   <li>{@link USPOOF_MIXED_SCRIPT_CONFUSABLE}</li>
*   <li>{@link USPOOF_WHOLE_SCRIPT_CONFUSABLE}</li>
* </ul>
*
* If one or more of the above flags were not listed in uspoof_setChecks(), this
* function will never report that class of confusable.  The check
* {@link USPOOF_CONFUSABLE} enables all three flags.
*
*
* @param sc      The USpoofChecker
* @param id1     The first of the two identifiers to be compared for
*                confusability.  The strings are in UTF-16 format.
* @param length1 the length of the first identifier, expressed in
*                16 bit UTF-16 code units, or -1 if the string is
*                nul terminated.
* @param id2     The second of the two identifiers to be compared for
*                confusability.  The identifiers are in UTF-16 format.
* @param length2 The length of the second identifiers, expressed in
*                16 bit UTF-16 code units, or -1 if the string is
*                nul terminated.
* @param status  The error code, set if an error occurred while attempting to
*                perform the check.
*                Confusability of the identifiers is not reported here,
*                but through this function's return value.
* @return        An integer value with bit(s) set corresponding to
*                the type of confusability found, as defined by
*                enum USpoofChecks.  Zero is returned if the identifiers
*                are not confusable.
*
* @stable ICU 4.2
*/
U_CAPI int32_t U_EXPORT2
uspoof_areConfusable(const USpoofChecker *sc,
                    const UChar *id1, int32_t length1,
                    const UChar *id2, int32_t length2,
                    UErrorCode *status);

/**
* Check whether two specified strings are visually confusable when
* displayed in a context with the given paragraph direction.
*
* If the strings are confusable, the return value will be nonzero, as long as
* {@link USPOOF_CONFUSABLE} was enabled in uspoof_setChecks().
*
* The bits in the return value correspond to flags for each of the classes of
* confusables applicable to the two input strings.  According to UTS 39
* section 4, the possible flags are:
*
* <ul>
*   <li>{@link USPOOF_SINGLE_SCRIPT_CONFUSABLE}</li>
*   <li>{@link USPOOF_MIXED_SCRIPT_CONFUSABLE}</li>
*   <li>{@link USPOOF_WHOLE_SCRIPT_CONFUSABLE}</li>
* </ul>
*
* If one or more of the above flags were not listed in uspoof_setChecks(), this
* function will never report that class of confusable.  The check
* {@link USPOOF_CONFUSABLE} enables all three flags.
*
*
* @param sc      The USpoofChecker
* @param direction The paragraph direction with which the identifiers are
*                displayed.  Must be either UBIDI_LTR or UBIDI_RTL.
* @param id1     The first of the two identifiers to be compared for
*                confusability.  The strings are in UTF-16 format.
* @param length1 the length of the first identifier, expressed in
*                16 bit UTF-16 code units, or -1 if the string is
*                nul terminated.
* @param id2     The second of the two identifiers to be compared for
*                confusability.  The identifiers are in UTF-16 format.
* @param length2 The length of the second identifiers, expressed in
*                16 bit UTF-16 code units, or -1 if the string is
*                nul terminated.
* @param status  The error code, set if an error occurred while attempting to
*                perform the check.
*                Confusability of the identifiers is not reported here,
*                but through this function's return value.
* @return        An integer value with bit(s) set corresponding to
*                the type of confusability found, as defined by
*                enum USpoofChecks.  Zero is returned if the identifiers
*                are not confusable.
*
* @stable ICU 74
*/
U_CAPI uint32_t U_EXPORT2 uspoof_areBidiConfusable(const USpoofChecker *sc, UBiDiDirection direction,
                                                 const UChar *id1, int32_t length1,
                                                 const UChar *id2, int32_t length2,
                                                 UErrorCode *status);

/**
* A version of {@link uspoof_areConfusable} accepting strings in UTF-8 format.
*
* @param sc      The USpoofChecker
* @param id1     The first of the two identifiers to be compared for
*                confusability.  The strings are in UTF-8 format.
* @param length1 the length of the first identifiers, in bytes, or -1
*                if the string is nul terminated.
* @param id2     The second of the two identifiers to be compared for
*                confusability.  The strings are in UTF-8 format.
* @param length2 The length of the second string in bytes, or -1
*                if the string is nul terminated.
* @param status  The error code, set if an error occurred while attempting to
*                perform the check.
*                Confusability of the strings is not reported here,
*                but through this function's return value.
* @return        An integer value with bit(s) set corresponding to
*                the type of confusability found, as defined by
*                enum USpoofChecks.  Zero is returned if the strings
*                are not confusable.
*
* @stable ICU 4.2
*
* @see uspoof_areConfusable
*/
U_CAPI int32_t U_EXPORT2
uspoof_areConfusableUTF8(const USpoofChecker *sc,
                        const char *id1, int32_t length1,
                        const char *id2, int32_t length2,
                        UErrorCode *status);

/**
* A version of {@link uspoof_areBidiConfusable} accepting strings in UTF-8 format.
*
* @param sc      The USpoofChecker
* @param direction The paragraph direction with which the identifiers are
*                displayed.  Must be either UBIDI_LTR or UBIDI_RTL.
* @param id1     The first of the two identifiers to be compared for
*                confusability.  The strings are in UTF-8 format.
* @param length1 the length of the first identifiers, in bytes, or -1
*                if the string is nul terminated.
* @param id2     The second of the two identifiers to be compared for
*                confusability.  The strings are in UTF-8 format.
* @param length2 The length of the second string in bytes, or -1
*                if the string is nul terminated.
* @param status  The error code, set if an error occurred while attempting to
*                perform the check.
*                Confusability of the strings is not reported here,
*                but through this function's return value.
* @return        An integer value with bit(s) set corresponding to
*                the type of confusability found, as defined by
*                enum USpoofChecks.  Zero is returned if the strings
*                are not confusable.
*
* @stable ICU 74
*
* @see uspoof_areBidiConfusable
*/
U_CAPI uint32_t U_EXPORT2 uspoof_areBidiConfusableUTF8(const USpoofChecker *sc, UBiDiDirection direction,
                                                     const char *id1, int32_t length1,
                                                     const char *id2, int32_t length2,
                                                     UErrorCode *status);

/**
*  Get the "skeleton" for an identifier.
*  Skeletons are a transformation of the input identifier;
* Two identifiers are confusable if their skeletons are identical.
*  See Unicode Technical Standard #39 for additional information.
*
*  Using skeletons directly makes it possible to quickly check
*  whether an identifier is confusable with any of some large
*  set of existing identifiers, by creating an efficiently
*  searchable collection of the skeletons.
*
* @param sc      The USpoofChecker
* @param type    Deprecated in ICU 58.  You may pass any number.
*                Originally, controlled which of the Unicode confusable data
*                tables to use.
* @param id      The input identifier whose skeleton will be computed.
* @param length  The length of the input identifier, expressed in 16 bit
*                UTF-16 code units, or -1 if the string is zero terminated.
* @param dest    The output buffer, to receive the skeleton string.
* @param destCapacity  The length of the output buffer, in 16 bit units.
*                The destCapacity may be zero, in which case the function will
*                return the actual length of the skeleton.
* @param status  The error code, set if an error occurred while attempting to
*                perform the check.
* @return        The length of the skeleton string.  The returned length
*                is always that of the complete skeleton, even when the
*                supplied buffer is too small (or of zero length)
*
* @stable ICU 4.2
* @see uspoof_areConfusable
*/
U_CAPI int32_t U_EXPORT2
uspoof_getSkeleton(const USpoofChecker *sc,
                  uint32_t type,
                  const UChar *id,  int32_t length,
                  UChar *dest, int32_t destCapacity,
                  UErrorCode *status);

/**
*  Get the "bidiSkeleton" for an identifier and a direction.
*  Skeletons are a transformation of the input identifier;
*  Two identifiers are LTR-confusable if their LTR bidiSkeletons are identical;
*  they are RTL-confusable if their RTL bidiSkeletons are identical.
*  See Unicode Technical Standard #39 for additional information:
*  https://www.unicode.org/reports/tr39/#Confusable_Detection.
*
*  Using skeletons directly makes it possible to quickly check
*  whether an identifier is confusable with any of some large
*  set of existing identifiers, by creating an efficiently
*  searchable collection of the skeletons.
*
* @param sc      The USpoofChecker.
* @param direction The context direction with which the identifier will be
*                displayed.  Must be either UBIDI_LTR or UBIDI_RTL.
* @param id      The input identifier whose skeleton will be computed.
* @param length  The length of the input identifier, expressed in 16 bit
*                UTF-16 code units, or -1 if the string is zero terminated.
* @param dest    The output buffer, to receive the skeleton string.
* @param destCapacity  The length of the output buffer, in 16 bit units.
*                The destCapacity may be zero, in which case the function will
*                return the actual length of the skeleton.
* @param status  The error code, set if an error occurred while attempting to
*                perform the check.
* @return        The length of the skeleton string.  The returned length
*                is always that of the complete skeleton, even when the
*                supplied buffer is too small (or of zero length)
*
* @stable ICU 74
* @see uspoof_areBidiConfusable
*/
U_CAPI int32_t U_EXPORT2 uspoof_getBidiSkeleton(const USpoofChecker *sc,
                                               UBiDiDirection direction,
                                               const UChar *id, int32_t length,
                                               UChar *dest, int32_t destCapacity, UErrorCode *status);

/**
*  Get the "skeleton" for an identifier.
*  Skeletons are a transformation of the input identifier;
*  Two identifiers are confusable if their skeletons are identical.
*  See Unicode Technical Standard #39 for additional information.
*
*  Using skeletons directly makes it possible to quickly check
*  whether an identifier is confusable with any of some large
*  set of existing identifiers, by creating an efficiently
*  searchable collection of the skeletons.
*
* @param sc      The USpoofChecker
* @param type    Deprecated in ICU 58.  You may pass any number.
*                Originally, controlled which of the Unicode confusable data
*                tables to use.
* @param id      The UTF-8 format identifier whose skeleton will be computed.
* @param length  The length of the input string, in bytes,
*                or -1 if the string is zero terminated.
* @param dest    The output buffer, to receive the skeleton string.
* @param destCapacity  The length of the output buffer, in bytes.
*                The destCapacity may be zero, in which case the function will
*                return the actual length of the skeleton.
* @param status  The error code, set if an error occurred while attempting to
*                perform the check.  Possible Errors include U_INVALID_CHAR_FOUND
*                   for invalid UTF-8 sequences, and
*                   U_BUFFER_OVERFLOW_ERROR if the destination buffer is too small
*                   to hold the complete skeleton.
* @return        The length of the skeleton string, in bytes.  The returned length
*                is always that of the complete skeleton, even when the
*                supplied buffer is too small (or of zero length)
*
* @stable ICU 4.2
*/
U_CAPI int32_t U_EXPORT2
uspoof_getSkeletonUTF8(const USpoofChecker *sc,
                      uint32_t type,
                      const char *id,  int32_t length,
                      char *dest, int32_t destCapacity,
                      UErrorCode *status);

/**
*  Get the "bidiSkeleton" for an identifier and a direction.
*  Skeletons are a transformation of the input identifier;
*  Two identifiers are LTR-confusable if their LTR bidiSkeletons are identical;
*  they are RTL-confusable if their RTL bidiSkeletons are identical.
*  See Unicode Technical Standard #39 for additional information:
*  https://www.unicode.org/reports/tr39/#Confusable_Detection.
*
*  Using skeletons directly makes it possible to quickly check
*  whether an identifier is confusable with any of some large
*  set of existing identifiers, by creating an efficiently
*  searchable collection of the skeletons.
*
* @param sc      The USpoofChecker
* @param direction The context direction with which the identifier will be
*                displayed.  Must be either UBIDI_LTR or UBIDI_RTL.
* @param id      The UTF-8 format identifier whose skeleton will be computed.
* @param length  The length of the input string, in bytes,
*                or -1 if the string is zero terminated.
* @param dest    The output buffer, to receive the skeleton string.
* @param destCapacity  The length of the output buffer, in bytes.
*                The destCapacity may be zero, in which case the function will
*                return the actual length of the skeleton.
* @param status  The error code, set if an error occurred while attempting to
*                perform the check.  Possible Errors include U_INVALID_CHAR_FOUND
*                for invalid UTF-8 sequences, and
*                U_BUFFER_OVERFLOW_ERROR if the destination buffer is too small
*                to hold the complete skeleton.
* @return        The length of the skeleton string, in bytes.  The returned length
*                is always that of the complete skeleton, even when the
*                supplied buffer is too small (or of zero length)
*
* @stable ICU 74
*/
U_CAPI int32_t U_EXPORT2 uspoof_getBidiSkeletonUTF8(const USpoofChecker *sc, UBiDiDirection direction,
                                                   const char *id, int32_t length, char *dest,
                                                   int32_t destCapacity, UErrorCode *status);

/**
 * Get the set of Candidate Characters for Inclusion in Identifiers, as defined
 * in http://unicode.org/Public/security/latest/xidmodifications.txt
 * and documented in http://www.unicode.org/reports/tr39/, Unicode Security Mechanisms.
 *
 * The returned set is frozen. Ownership of the set remains with the ICU library; it must not
 * be deleted by the caller.
 *
 * @param status The error code, set if a problem occurs while creating the set.
 *
 * @stable ICU 51
 */
U_CAPI const USet * U_EXPORT2
uspoof_getInclusionSet(UErrorCode *status);

/**
 * Get the set of characters from Recommended Scripts for Inclusion in Identifiers, as defined
 * in http://unicode.org/Public/security/latest/xidmodifications.txt
 * and documented in http://www.unicode.org/reports/tr39/, Unicode Security Mechanisms.
 *
 * The returned set is frozen. Ownership of the set remains with the ICU library; it must not
 * be deleted by the caller.
 *
 * @param status The error code, set if a problem occurs while creating the set.
 *
 * @stable ICU 51
 */
U_CAPI const USet * U_EXPORT2
uspoof_getRecommendedSet(UErrorCode *status);

/**
* Serialize the data for a spoof detector into a chunk of memory.
* The flattened spoof detection tables can later be used to efficiently
* instantiate a new Spoof Detector.
*
* The serialized spoof checker includes only the data compiled from the
* Unicode data tables by uspoof_openFromSource(); it does not include
* include any other state or configuration that may have been set.
*
* @param sc   the Spoof Detector whose data is to be serialized.
* @param data a pointer to 32-bit-aligned memory to be filled with the data,
*             can be NULL if capacity==0
* @param capacity the number of bytes available at data,
*                 or 0 for preflighting
* @param status an in/out ICU UErrorCode; possible errors include:
* - U_BUFFER_OVERFLOW_ERROR if the data storage block is too small for serialization
* - U_ILLEGAL_ARGUMENT_ERROR  the data or capacity parameters are bad
* @return the number of bytes written or needed for the spoof data
*
* @see utrie2_openFromSerialized()
* @stable ICU 4.2
*/
U_CAPI int32_t U_EXPORT2
uspoof_serialize(USpoofChecker *sc,
                void *data, int32_t capacity,
                UErrorCode *status);

U_CDECL_END

#if U_SHOW_CPLUSPLUS_API

U_NAMESPACE_BEGIN

/**
* \class LocalUSpoofCheckerPointer
* "Smart pointer" class, closes a USpoofChecker via uspoof_close().
* For most methods see the LocalPointerBase base class.
*
* @see LocalPointerBase
* @see LocalPointer
* @stable ICU 4.4
*/
/**
* \cond
* Note: Doxygen is giving a bogus warning on this U_DEFINE_LOCAL_OPEN_POINTER.
*       For now, suppress with a Doxygen cond
*/
U_DEFINE_LOCAL_OPEN_POINTER(LocalUSpoofCheckerPointer, USpoofChecker, uspoof_close);
/** \endcond */

/**
* \class LocalUSpoofCheckResultPointer
* "Smart pointer" class, closes a USpoofCheckResult via `uspoof_closeCheckResult()`.
* For most methods see the LocalPointerBase base class.
*
* @see LocalPointerBase
* @see LocalPointer
* @stable ICU 58
*/

/**
* \cond
* Note: Doxygen is giving a bogus warning on this U_DEFINE_LOCAL_OPEN_POINTER.
*       For now, suppress with a Doxygen cond
*/
U_DEFINE_LOCAL_OPEN_POINTER(LocalUSpoofCheckResultPointer, USpoofCheckResult, uspoof_closeCheckResult);
/** \endcond */

U_NAMESPACE_END

/**
* Limit the acceptable characters to those specified by a Unicode Set.
*   Any previously specified character limit is
*   is replaced by the new settings.    This includes limits on
*   characters that were set with the uspoof_setAllowedLocales() function.
*
* The USPOOF_CHAR_LIMIT test is automatically enabled for this
* USoofChecker by this function.
*
* @param sc       The USpoofChecker
* @param chars    A Unicode Set containing the list of
*                 characters that are permitted.  Ownership of the set
*                 remains with the caller.  The incoming set is cloned by
*                 this function, so there are no restrictions on modifying
*                 or deleting the UnicodeSet after calling this function.
* @param status   The error code, set if this function encounters a problem.
* @stable ICU 4.2
*/
U_CAPI void U_EXPORT2
uspoof_setAllowedUnicodeSet(USpoofChecker *sc, const icu::UnicodeSet *chars, UErrorCode *status);


/**
* Get a UnicodeSet for the characters permitted in an identifier.
* This corresponds to the limits imposed by the Set Allowed Characters /
* UnicodeSet functions. Limitations imposed by other checks will not be
* reflected in the set returned by this function.
*
* The returned set will be frozen, meaning that it cannot be modified
* by the caller.
*
* Ownership of the returned set remains with the Spoof Detector.  The
* returned set will become invalid if the spoof detector is closed,
* or if a new set of allowed characters is specified.
*
*
* @param sc       The USpoofChecker
* @param status   The error code, set if this function encounters a problem.
* @return         A UnicodeSet containing the characters that are permitted by
*                 the USPOOF_CHAR_LIMIT test.
* @stable ICU 4.2
*/
U_CAPI const icu::UnicodeSet * U_EXPORT2
uspoof_getAllowedUnicodeSet(const USpoofChecker *sc, UErrorCode *status);

/**
* Check the specified string for possible security issues.
* The text to be checked will typically be an identifier of some sort.
* The set of checks to be performed is specified with uspoof_setChecks().
*
* \note
*   Consider using the newer API, {@link uspoof_check2UnicodeString}, instead.
*   The newer API exposes additional information from the check procedure
*   and is otherwise identical to this method.
*
* @param sc      The USpoofChecker
* @param id      A identifier to be checked for possible security issues.
* @param position  Deprecated in ICU 51.  Always returns zero.
*                Originally, an out parameter for the index of the first
*                string position that failed a check.
*                This parameter may be nullptr.
* @param status  The error code, set if an error occurred while attempting to
*                perform the check.
*                Spoofing or security issues detected with the input string are
*                not reported here, but through the function's return value.
* @return        An integer value with bits set for any potential security
*                or spoofing issues detected.  The bits are defined by
*                enum USpoofChecks.  (returned_value & USPOOF_ALL_CHECKS)
*                will be zero if the input string passes all of the
*                enabled checks.
* @see uspoof_check2UnicodeString
* @stable ICU 4.2
*/
U_CAPI int32_t U_EXPORT2
uspoof_checkUnicodeString(const USpoofChecker *sc,
                         const icu::UnicodeString &id,
                         int32_t *position,
                         UErrorCode *status);

/**
* Check the specified string for possible security issues.
* The text to be checked will typically be an identifier of some sort.
* The set of checks to be performed is specified with uspoof_setChecks().
*
* @param sc      The USpoofChecker
* @param id      A identifier to be checked for possible security issues.
* @param checkResult  An instance of USpoofCheckResult to be filled with
*                details about the identifier.  Can be nullptr.
* @param status  The error code, set if an error occurred while attempting to
*                perform the check.
*                Spoofing or security issues detected with the input string are
*                not reported here, but through the function's return value.
* @return        An integer value with bits set for any potential security
*                or spoofing issues detected.  The bits are defined by
*                enum USpoofChecks.  (returned_value & USPOOF_ALL_CHECKS)
*                will be zero if the input string passes all of the
*                enabled checks.  Any information in this bitmask will be
*                consistent with the information saved in the optional
*                checkResult parameter.
* @see uspoof_openCheckResult
* @see uspoof_check2
* @see uspoof_check2UTF8
* @stable ICU 58
*/
U_CAPI int32_t U_EXPORT2
uspoof_check2UnicodeString(const USpoofChecker *sc,
   const icu::UnicodeString &id,
   USpoofCheckResult* checkResult,
   UErrorCode *status);

/**
* A version of {@link uspoof_areConfusable} accepting UnicodeStrings.
*
* @param sc      The USpoofChecker
* @param s1     The first of the two identifiers to be compared for
*                confusability.  The strings are in UTF-8 format.
* @param s2     The second of the two identifiers to be compared for
*                confusability.  The strings are in UTF-8 format.
* @param status  The error code, set if an error occurred while attempting to
*                perform the check.
*                Confusability of the identifiers is not reported here,
*                but through this function's return value.
* @return        An integer value with bit(s) set corresponding to
*                the type of confusability found, as defined by
*                enum USpoofChecks.  Zero is returned if the identifiers
*                are not confusable.
*
* @stable ICU 4.2
*
* @see uspoof_areConfusable
*/
U_CAPI int32_t U_EXPORT2
uspoof_areConfusableUnicodeString(const USpoofChecker *sc,
                                 const icu::UnicodeString &s1,
                                 const icu::UnicodeString &s2,
                                 UErrorCode *status);

/**
* A version of {@link uspoof_areBidiConfusable} accepting UnicodeStrings.
*
* @param sc      The USpoofChecker
* @param direction The paragraph direction with which the identifiers are
*                displayed.  Must be either UBIDI_LTR or UBIDI_RTL.
* @param s1     The first of the two identifiers to be compared for
*                confusability.  The strings are in UTF-8 format.
* @param s2     The second of the two identifiers to be compared for
*                confusability.  The strings are in UTF-8 format.
* @param status  The error code, set if an error occurred while attempting to
*                perform the check.
*                Confusability of the identifiers is not reported here,
*                but through this function's return value.
* @return        An integer value with bit(s) set corresponding to
*                the type of confusability found, as defined by
*                enum USpoofChecks.  Zero is returned if the identifiers
*                are not confusable.
*
* @stable ICU 74
*
* @see uspoof_areBidiConfusable
*/
U_CAPI uint32_t U_EXPORT2 uspoof_areBidiConfusableUnicodeString(const USpoofChecker *sc,
                                                              UBiDiDirection direction,
                                                              const icu::UnicodeString &s1,
                                                              const icu::UnicodeString &s2,
                                                              UErrorCode *status);

/**
*  Get the "skeleton" for an identifier.
*  Skeletons are a transformation of the input identifier;
*  Two identifiers are confusable if their skeletons are identical.
*  See Unicode Technical Standard #39 for additional information.
*
*  Using skeletons directly makes it possible to quickly check
*  whether an identifier is confusable with any of some large
*  set of existing identifiers, by creating an efficiently
*  searchable collection of the skeletons.
*
* @param sc      The USpoofChecker.
* @param type    Deprecated in ICU 58.  You may pass any number.
*                Originally, controlled which of the Unicode confusable data
*                tables to use.
* @param id      The input identifier whose skeleton will be computed.
* @param dest    The output identifier, to receive the skeleton string.
* @param status  The error code, set if an error occurred while attempting to
*                perform the check.
* @return        A reference to the destination (skeleton) string.
*
* @stable ICU 4.2
*/
U_I18N_API icu::UnicodeString & U_EXPORT2
uspoof_getSkeletonUnicodeString(const USpoofChecker *sc,
                               uint32_t type,
                               const icu::UnicodeString &id,
                               icu::UnicodeString &dest,
                               UErrorCode *status);

/**
*  Get the "bidiSkeleton" for an identifier and a direction.
*  Skeletons are a transformation of the input identifier;
*  Two identifiers are LTR-confusable if their LTR bidiSkeletons are identical;
*  they are RTL-confusable if their RTL bidiSkeletons are identical.
*  See Unicode Technical Standard #39 for additional information.
*  https://www.unicode.org/reports/tr39/#Confusable_Detection.
*
*  Using skeletons directly makes it possible to quickly check
*  whether an identifier is confusable with any of some large
*  set of existing identifiers, by creating an efficiently
*  searchable collection of the skeletons.
*
* @param sc      The USpoofChecker.
* @param direction The context direction with which the identifier will be
*                displayed.  Must be either UBIDI_LTR or UBIDI_RTL.
* @param id      The input identifier whose bidiSkeleton will be computed.
* @param dest    The output identifier, to receive the skeleton string.
* @param status  The error code, set if an error occurred while attempting to
*                perform the check.
* @return        A reference to the destination (skeleton) string.
*
* @stable ICU 74
*/
U_I18N_API icu::UnicodeString &U_EXPORT2 uspoof_getBidiSkeletonUnicodeString(
   const USpoofChecker *sc, UBiDiDirection direction, const icu::UnicodeString &id,
   icu::UnicodeString &dest, UErrorCode *status);

/**
 * Get the set of Candidate Characters for Inclusion in Identifiers, as defined
 * in http://unicode.org/Public/security/latest/xidmodifications.txt
 * and documented in http://www.unicode.org/reports/tr39/, Unicode Security Mechanisms.
 *
 * The returned set is frozen. Ownership of the set remains with the ICU library; it must not
 * be deleted by the caller.
 *
 * @param status The error code, set if a problem occurs while creating the set.
 *
 * @stable ICU 51
 */
U_CAPI const icu::UnicodeSet * U_EXPORT2
uspoof_getInclusionUnicodeSet(UErrorCode *status);

/**
 * Get the set of characters from Recommended Scripts for Inclusion in Identifiers, as defined
 * in http://unicode.org/Public/security/latest/xidmodifications.txt
 * and documented in http://www.unicode.org/reports/tr39/, Unicode Security Mechanisms.
 *
 * The returned set is frozen. Ownership of the set remains with the ICU library; it must not
 * be deleted by the caller.
 *
 * @param status The error code, set if a problem occurs while creating the set.
 *
 * @stable ICU 51
 */
U_CAPI const icu::UnicodeSet * U_EXPORT2
uspoof_getRecommendedUnicodeSet(UErrorCode *status);

#endif /* U_SHOW_CPLUSPLUS_API */

#endif /* UCONFIG_NO_NORMALIZATION */

#endif   /* USPOOF_H */