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      1 /*
      2 ***************************************************************************
      3 * Copyright (C) 2008-2013, International Business Machines Corporation
      4 * and others. All Rights Reserved.
      5 ***************************************************************************
      6 *   file name:  uspoof.h
      7 *   encoding:   US-ASCII
      8 *   tab size:   8 (not used)
      9 *   indentation:4
     10 *
     11 *   created on: 2008Feb13
     12 *   created by: Andy Heninger
     13 *
     14 *   Unicode Spoof Detection
     15 */
     16 
     17 #ifndef USPOOF_H
     18 #define USPOOF_H
     19 
     20 #include "unicode/utypes.h"
     21 #include "unicode/uset.h"
     22 #include "unicode/parseerr.h"
     23 #include "unicode/localpointer.h"
     24 
     25 #if !UCONFIG_NO_NORMALIZATION
     26 
     27 
     28 #if U_SHOW_CPLUSPLUS_API
     29 #include "unicode/unistr.h"
     30 #include "unicode/uniset.h"
     31 #endif
     32 
     33 
     34 /**
     35  * \file
     36  * \brief Unicode Security and Spoofing Detection, C API.
     37  *
     38  * These functions are intended to check strings, typically
     39  * identifiers of some type, such as URLs, for the presence of
     40  * characters that are likely to be visually confusing -
     41  * for cases where the displayed form of an identifier may
     42  * not be what it appears to be.
     43  *
     44  * Unicode Technical Report #36, http://unicode.org/reports/tr36, and
     45  * Unicode Technical Standard #39, http://unicode.org/reports/tr39
     46  * "Unicode security considerations", give more background on
     47  * security an spoofing issues with Unicode identifiers.
     48  * The tests and checks provided by this module implement the recommendations
     49  * from those Unicode documents.
     50  *
     51  * The tests available on identifiers fall into two general categories:
     52  *   -#  Single identifier tests.  Check whether an identifier is
     53  *       potentially confusable with any other string, or is suspicious
     54  *       for other reasons.
     55  *   -#  Two identifier tests.  Check whether two specific identifiers are confusable.
     56  *       This does not consider whether either of strings is potentially
     57  *       confusable with any string other than the exact one specified.
     58  *
     59  * The steps to perform confusability testing are
     60  *   -#  Open a USpoofChecker.
     61  *   -#  Configure the USPoofChecker for the desired set of tests.  The tests that will
     62  *       be performed are specified by a set of USpoofChecks flags.
     63  *   -#  Perform the checks using the pre-configured USpoofChecker.  The results indicate
     64  *       which (if any) of the selected tests have identified possible problems with the identifier.
     65  *       Results are reported as a set of USpoofChecks flags;  this mirrors the form in which
     66  *       the set of tests to perform was originally specified to the USpoofChecker.
     67  *
     68  * A USpoofChecker may be used repeatedly to perform checks on any number of identifiers.
     69  *
     70  * Thread Safety: The test functions for checking a single identifier, or for testing
     71  * whether two identifiers are possible confusable, are thread safe.
     72  * They may called concurrently, from multiple threads, using the same USpoofChecker instance.
     73  *
     74  * More generally, the standard ICU thread safety rules apply:  functions that take a
     75  * const USpoofChecker parameter are thread safe.  Those that take a non-const
     76  * USpoofChecier are not thread safe.
     77  *
     78  *
     79  * Descriptions of the available checks.
     80  *
     81  * When testing whether pairs of identifiers are confusable, with the uspoof_areConfusable()
     82  * family of functions, the relevant tests are
     83  *
     84  *   -# USPOOF_SINGLE_SCRIPT_CONFUSABLE:  All of the characters from the two identifiers are
     85  *      from a single script, and the two identifiers are visually confusable.
     86  *   -# USPOOF_MIXED_SCRIPT_CONFUSABLE:  At least one of the identifiers contains characters
     87  *      from more than one script, and the two identifiers are visually confusable.
     88  *   -# USPOOF_WHOLE_SCRIPT_CONFUSABLE: Each of the two identifiers is of a single script, but
     89  *      the two identifiers are from different scripts, and they are visually confusable.
     90  *
     91  * The safest approach is to enable all three of these checks as a group.
     92  *
     93  * USPOOF_ANY_CASE is a modifier for the above tests.  If the identifiers being checked can
     94  * be of mixed case and are used in a case-sensitive manner, this option should be specified.
     95  *
     96  * If the identifiers being checked are used in a case-insensitive manner, and if they are
     97  * displayed to users in lower-case form only, the USPOOF_ANY_CASE option should not be
     98  * specified.  Confusabality issues involving upper case letters will not be reported.
     99  *
    100  * When performing tests on a single identifier, with the uspoof_check() family of functions,
    101  * the relevant tests are:
    102  *
    103  *    -# USPOOF_MIXED_SCRIPT_CONFUSABLE: the identifier contains characters from multiple
    104  *       scripts, and there exists an identifier of a single script that is visually confusable.
    105  *    -# USPOOF_WHOLE_SCRIPT_CONFUSABLE: the identifier consists of characters from a single
    106  *       script, and there exists a visually confusable identifier.
    107  *       The visually confusable identifier also consists of characters from a single script.
    108  *       but not the same script as the identifier being checked.
    109  *    -# USPOOF_ANY_CASE: modifies the mixed script and whole script confusables tests.  If
    110  *       specified, the checks will consider confusable characters of any case.  If this flag is not
    111  *       set, the test is performed assuming case folded identifiers.
    112  *    -# USPOOF_SINGLE_SCRIPT: check that the identifier contains only characters from a
    113  *       single script.  (Characters from the 'common' and 'inherited' scripts are ignored.)
    114  *       This is not a test for confusable identifiers
    115  *    -# USPOOF_INVISIBLE: check an identifier for the presence of invisible characters,
    116  *       such as zero-width spaces, or character sequences that are
    117  *       likely not to display, such as multiple occurrences of the same
    118  *       non-spacing mark.  This check does not test the input string as a whole
    119  *       for conformance to any particular syntax for identifiers.
    120  *    -# USPOOF_CHAR_LIMIT: check that an identifier contains only characters from a specified set
    121  *       of acceptable characters.  See uspoof_setAllowedChars() and
    122  *       uspoof_setAllowedLocales().
    123  *
    124  *  Note on Scripts:
    125  *     Characters from the Unicode Scripts "Common" and "Inherited" are ignored when considering
    126  *     the script of an identifier. Common characters include digits and symbols that
    127  *     are normally used with text from more than one script.
    128  *
    129  *  Identifier Skeletons:  A skeleton is a transformation of an identifier, such that
    130  *  all identifiers that are confusable with each other have the same skeleton.
    131  *  Using skeletons, it is possible to build a dictionary data structure for
    132  *  a set of identifiers, and then quickly test whether a new identifier is
    133  *  confusable with an identifier already in the set.  The uspoof_getSkeleton()
    134  *  family of functions will produce the skeleton from an identifier.
    135  *
    136  *  Note that skeletons are not guaranteed to be stable between versions
    137  *  of Unicode or ICU, so an applications should not rely on creating a permanent,
    138  *  or difficult to update, database of skeletons.  Instabilities result from
    139  *  identifying new pairs or sequences of characters that are visually
    140  *  confusable, and thus must be mapped to the same skeleton character(s).
    141  *
    142  */
    143 
    144 struct USpoofChecker;
    145 typedef struct USpoofChecker USpoofChecker; /**< typedef for C of USpoofChecker */
    146 
    147 /**
    148  * Enum for the kinds of checks that USpoofChecker can perform.
    149  * These enum values are used both to select the set of checks that
    150  * will be performed, and to report results from the check function.
    151  *
    152  * @stable ICU 4.2
    153  */
    154 typedef enum USpoofChecks {
    155     /**   Single script confusable test.
    156       *   When testing whether two identifiers are confusable, report that they are if
    157       *   both are from the same script and they are visually confusable.
    158       *   Note: this test is not applicable to a check of a single identifier.
    159       */
    160     USPOOF_SINGLE_SCRIPT_CONFUSABLE =   1,
    161 
    162     /** Mixed script confusable test.
    163      *  When checking a single identifier, report a problem if
    164      *    the identifier contains multiple scripts, and
    165      *    is confusable with some other identifier in a single script
    166      *  When testing whether two identifiers are confusable, report that they are if
    167      *    the two IDs are visually confusable,
    168      *    and at least one contains characters from more than one script.
    169      */
    170     USPOOF_MIXED_SCRIPT_CONFUSABLE  =   2,
    171 
    172     /** Whole script confusable test.
    173      *  When checking a single identifier, report a problem if
    174      *    The identifier is of a single script, and
    175      *    there exists a confusable identifier in another script.
    176      *  When testing whether two identifiers are confusable, report that they are if
    177      *    each is of a single script,
    178      *    the scripts of the two identifiers are different, and
    179      *    the identifiers are visually confusable.
    180      */
    181     USPOOF_WHOLE_SCRIPT_CONFUSABLE  =   4,
    182 
    183     /** Any Case Modifier for confusable identifier tests.
    184         If specified, consider all characters, of any case, when looking for confusables.
    185         If USPOOF_ANY_CASE is not specified, identifiers being checked are assumed to have been
    186         case folded.  Upper case confusable characters will not be checked.
    187         Selects between Lower Case Confusable and
    188         Any Case Confusable.   */
    189     USPOOF_ANY_CASE                 =   8,
    190 
    191     /**
    192       * Check that an identifier is no looser than the specified RestrictionLevel.
    193       * The default if uspoof_setRestrctionLevel() is not called is HIGHLY_RESTRICTIVE.
    194       *
    195       * If USPOOF_AUX_INFO is enabled the actual restriction level of the
    196       * identifier being tested will also be returned by uspoof_check().
    197       *
    198       * @see URestrictionLevel
    199       * @see uspoof_setRestrictionLevel
    200       * @see USPOOF_AUX_INFO
    201       *
    202       * @stable ICU 51
    203       */
    204     USPOOF_RESTRICTION_LEVEL        = 16,
    205 
    206 #ifndef U_HIDE_DEPRECATED_API
    207     /** Check that an identifier contains only characters from a
    208       * single script (plus chars from the common and inherited scripts.)
    209       * Applies to checks of a single identifier check only.
    210       * @deprecated ICU 51  Use RESTRICTION_LEVEL instead.
    211       */
    212     USPOOF_SINGLE_SCRIPT            =  USPOOF_RESTRICTION_LEVEL,
    213 #endif  /* U_HIDE_DEPRECATED_API */
    214 
    215     /** Check an identifier for the presence of invisible characters,
    216       * such as zero-width spaces, or character sequences that are
    217       * likely not to display, such as multiple occurrences of the same
    218       * non-spacing mark.  This check does not test the input string as a whole
    219       * for conformance to any particular syntax for identifiers.
    220       */
    221     USPOOF_INVISIBLE                =  32,
    222 
    223     /** Check that an identifier contains only characters from a specified set
    224       * of acceptable characters.  See uspoof_setAllowedChars() and
    225       * uspoof_setAllowedLocales().
    226       */
    227     USPOOF_CHAR_LIMIT               =  64,
    228 
    229 #ifndef U_HIDE_DRAFT_API
    230    /**
    231      * Check that an identifier does not include decimal digits from
    232      * more than one numbering system.
    233      *
    234      * @draft ICU 51
    235      */
    236     USPOOF_MIXED_NUMBERS            = 128,
    237 #endif /* U_HIDE_DRAFT_API */
    238 
    239    /**
    240      * Enable all spoof checks.
    241      *
    242      * @stable ICU 4.6
    243      */
    244     USPOOF_ALL_CHECKS               = 0xFFFF,
    245 
    246 #ifndef U_HIDE_DRAFT_API
    247     /**
    248       * Enable the return of auxillary (non-error) information in the
    249       * upper bits of the check results value.
    250       *
    251       * If this "check" is not enabled, the results of uspoof_check() will be zero when an
    252       * identifier passes all of the enabled checks.
    253       *
    254       * If this "check" is enabled, (uspoof_check() & USPOOF_ALL_CHECKS) will be zero
    255       * when an identifier passes all checks.
    256       *
    257       * @draft ICU 51
    258       */
    259     USPOOF_AUX_INFO                  = 0x40000000
    260 #endif /* U_HIDE_DRAFT_API */
    261 
    262     } USpoofChecks;
    263 
    264 
    265 #ifndef U_HIDE_DRAFT_API
    266     /**
    267      * Constants from UAX #39 for use in setRestrictionLevel(), and
    268      * for returned identifier restriction levels in check results.
    269      * @draft ICU 51
    270      */
    271     typedef enum URestrictionLevel {
    272         /**
    273          * Only ASCII characters: U+0000..U+007F
    274          *
    275          * @draft ICU 51
    276          */
    277         USPOOF_ASCII = 0x10000000,
    278         /**
    279          * All characters in each identifier must be from a single script, or from the combinations: Latin + Han +
    280          * Hiragana + Katakana; Latin + Han + Bopomofo; or Latin + Han + Hangul. Note that this level will satisfy the
    281          * vast majority of Latin-script users; also that TR36 has ASCII instead of Latin.
    282          *
    283          * @draft ICU 51
    284          */
    285         USPOOF_HIGHLY_RESTRICTIVE = 0x20000000,
    286         /**
    287          * Allow Latin with other scripts except Cyrillic, Greek, Cherokee Otherwise, the same as Highly Restrictive
    288          *
    289          * @draft ICU 51
    290          */
    291         USPOOF_MODERATELY_RESTRICTIVE = 0x30000000,
    292         /**
    293          * Allow arbitrary mixtures of scripts. Otherwise, the same as Moderately Restrictive.
    294          *
    295          * @draft ICU 51
    296          */
    297         USPOOF_MINIMALLY_RESTRICTIVE = 0x40000000,
    298         /**
    299          * Any valid identifiers, including characters outside of the Identifier Profile.
    300          *
    301          * @draft ICU 51
    302          */
    303         USPOOF_UNRESTRICTIVE = 0x50000000
    304     } URestrictionLevel;
    305 #endif /* U_HIDE_DRAFT_API */
    306 
    307 /**
    308  *  Create a Unicode Spoof Checker, configured to perform all
    309  *  checks except for USPOOF_LOCALE_LIMIT and USPOOF_CHAR_LIMIT.
    310  *  Note that additional checks may be added in the future,
    311  *  resulting in the changes to the default checking behavior.
    312  *
    313  *  @param status  The error code, set if this function encounters a problem.
    314  *  @return        the newly created Spoof Checker
    315  *  @stable ICU 4.2
    316  */
    317 U_STABLE USpoofChecker * U_EXPORT2
    318 uspoof_open(UErrorCode *status);
    319 
    320 
    321 /**
    322  * Open a Spoof checker from its serialized from, stored in 32-bit-aligned memory.
    323  * Inverse of uspoof_serialize().
    324  * The memory containing the serialized data must remain valid and unchanged
    325  * as long as the spoof checker, or any cloned copies of the spoof checker,
    326  * are in use.  Ownership of the memory remains with the caller.
    327  * The spoof checker (and any clones) must be closed prior to deleting the
    328  * serialized data.
    329  *
    330  * @param data a pointer to 32-bit-aligned memory containing the serialized form of spoof data
    331  * @param length the number of bytes available at data;
    332  *               can be more than necessary
    333  * @param pActualLength receives the actual number of bytes at data taken up by the data;
    334  *                      can be NULL
    335  * @param pErrorCode ICU error code
    336  * @return the spoof checker.
    337  *
    338  * @see uspoof_open
    339  * @see uspoof_serialize
    340  * @stable ICU 4.2
    341  */
    342 U_STABLE USpoofChecker * U_EXPORT2
    343 uspoof_openFromSerialized(const void *data, int32_t length, int32_t *pActualLength,
    344                           UErrorCode *pErrorCode);
    345 
    346 /**
    347   * Open a Spoof Checker from the source form of the spoof data.
    348   * The Three inputs correspond to the Unicode data files confusables.txt
    349   * confusablesWholeScript.txt and xidmdifications.txt as described in
    350   * Unicode UAX #39.  The syntax of the source data is as described in UAX #39 for
    351   * these files, and the content of these files is acceptable input.
    352   *
    353   * The character encoding of the (char *) input text is UTF-8.
    354   *
    355   * @param confusables a pointer to the confusable characters definitions,
    356   *                    as found in file confusables.txt from unicode.org.
    357   * @param confusablesLen The length of the confusables text, or -1 if the
    358   *                    input string is zero terminated.
    359   * @param confusablesWholeScript
    360   *                    a pointer to the whole script confusables definitions,
    361   *                    as found in the file confusablesWholeScript.txt from unicode.org.
    362   * @param confusablesWholeScriptLen The length of the whole script confusables text, or
    363   *                    -1 if the input string is zero terminated.
    364   * @param errType     In the event of an error in the input, indicates
    365   *                    which of the input files contains the error.
    366   *                    The value is one of USPOOF_SINGLE_SCRIPT_CONFUSABLE or
    367   *                    USPOOF_WHOLE_SCRIPT_CONFUSABLE, or
    368   *                    zero if no errors are found.
    369   * @param pe          In the event of an error in the input, receives the position
    370   *                    in the input text (line, offset) of the error.
    371   * @param status      an in/out ICU UErrorCode.  Among the possible errors is
    372   *                    U_PARSE_ERROR, which is used to report syntax errors
    373   *                    in the input.
    374   * @return            A spoof checker that uses the rules from the input files.
    375   * @stable ICU 4.2
    376   */
    377 U_STABLE USpoofChecker * U_EXPORT2
    378 uspoof_openFromSource(const char *confusables,  int32_t confusablesLen,
    379                       const char *confusablesWholeScript, int32_t confusablesWholeScriptLen,
    380                       int32_t *errType, UParseError *pe, UErrorCode *status);
    381 
    382 
    383 /**
    384   * Close a Spoof Checker, freeing any memory that was being held by
    385   *   its implementation.
    386   * @stable ICU 4.2
    387   */
    388 U_STABLE void U_EXPORT2
    389 uspoof_close(USpoofChecker *sc);
    390 
    391 #if U_SHOW_CPLUSPLUS_API
    392 
    393 U_NAMESPACE_BEGIN
    394 
    395 /**
    396  * \class LocalUSpoofCheckerPointer
    397  * "Smart pointer" class, closes a USpoofChecker via uspoof_close().
    398  * For most methods see the LocalPointerBase base class.
    399  *
    400  * @see LocalPointerBase
    401  * @see LocalPointer
    402  * @stable ICU 4.4
    403  */
    404 U_DEFINE_LOCAL_OPEN_POINTER(LocalUSpoofCheckerPointer, USpoofChecker, uspoof_close);
    405 
    406 U_NAMESPACE_END
    407 
    408 #endif
    409 
    410 /**
    411  * Clone a Spoof Checker.  The clone will be set to perform the same checks
    412  *   as the original source.
    413  *
    414  * @param sc       The source USpoofChecker
    415  * @param status   The error code, set if this function encounters a problem.
    416  * @return
    417  * @stable ICU 4.2
    418  */
    419 U_STABLE USpoofChecker * U_EXPORT2
    420 uspoof_clone(const USpoofChecker *sc, UErrorCode *status);
    421 
    422 
    423 /**
    424  * Specify the set of checks that will be performed by the check
    425  * functions of this Spoof Checker.
    426  *
    427  * @param sc       The USpoofChecker
    428  * @param checks         The set of checks that this spoof checker will perform.
    429  *                 The value is a bit set, obtained by OR-ing together
    430  *                 values from enum USpoofChecks.
    431  * @param status   The error code, set if this function encounters a problem.
    432  * @stable ICU 4.2
    433  *
    434  */
    435 U_STABLE void U_EXPORT2
    436 uspoof_setChecks(USpoofChecker *sc, int32_t checks, UErrorCode *status);
    437 
    438 /**
    439  * Get the set of checks that this Spoof Checker has been configured to perform.
    440  *
    441  * @param sc       The USpoofChecker
    442  * @param status   The error code, set if this function encounters a problem.
    443  * @return         The set of checks that this spoof checker will perform.
    444  *                 The value is a bit set, obtained by OR-ing together
    445  *                 values from enum USpoofChecks.
    446  * @stable ICU 4.2
    447  *
    448  */
    449 U_STABLE int32_t U_EXPORT2
    450 uspoof_getChecks(const USpoofChecker *sc, UErrorCode *status);
    451 
    452 #ifndef U_HIDE_DRAFT_API
    453 /**
    454   * Set the loosest restriction level allowed. The default if this function
    455   * is not called is HIGHLY_RESTRICTIVE.
    456   * Calling this function also enables the RESTRICTION_LEVEL check.
    457   * @param restrictionLevel The loosest restriction level allowed.
    458   * @see URestrictionLevel
    459   * @draft ICU 51
    460   */
    461 U_DRAFT void U_EXPORT2
    462 uspoof_setRestrictionLevel(USpoofChecker *sc, URestrictionLevel restrictionLevel);
    463 
    464 
    465 /**
    466   * Get the Restriction Level that will be tested if the checks include RESTRICTION_LEVEL.
    467   *
    468   * @return The restriction level
    469   * @see URestrictionLevel
    470   * @draft ICU 51
    471   */
    472 U_DRAFT URestrictionLevel U_EXPORT2
    473 uspoof_getRestrictionLevel(const USpoofChecker *sc);
    474 #endif /* U_HIDE_DRAFT_API */
    475 
    476 /**
    477  * Limit characters that are acceptable in identifiers being checked to those
    478  * normally used with the languages associated with the specified locales.
    479  * Any previously specified list of locales is replaced by the new settings.
    480  *
    481  * A set of languages is determined from the locale(s), and
    482  * from those a set of acceptable Unicode scripts is determined.
    483  * Characters from this set of scripts, along with characters from
    484  * the "common" and "inherited" Unicode Script categories
    485  * will be permitted.
    486  *
    487  * Supplying an empty string removes all restrictions;
    488  * characters from any script will be allowed.
    489  *
    490  * The USPOOF_CHAR_LIMIT test is automatically enabled for this
    491  * USpoofChecker when calling this function with a non-empty list
    492  * of locales.
    493  *
    494  * The Unicode Set of characters that will be allowed is accessible
    495  * via the uspoof_getAllowedChars() function.  uspoof_setAllowedLocales()
    496  * will <i>replace</i> any previously applied set of allowed characters.
    497  *
    498  * Adjustments, such as additions or deletions of certain classes of characters,
    499  * can be made to the result of uspoof_setAllowedLocales() by
    500  * fetching the resulting set with uspoof_getAllowedChars(),
    501  * manipulating it with the Unicode Set API, then resetting the
    502  * spoof detectors limits with uspoof_setAllowedChars()
    503  *
    504  * @param sc           The USpoofChecker
    505  * @param localesList  A list list of locales, from which the language
    506  *                     and associated script are extracted.  The locales
    507  *                     are comma-separated if there is more than one.
    508  *                     White space may not appear within an individual locale,
    509  *                     but is ignored otherwise.
    510  *                     The locales are syntactically like those from the
    511  *                     HTTP Accept-Language header.
    512  *                     If the localesList is empty, no restrictions will be placed on
    513  *                     the allowed characters.
    514  *
    515  * @param status       The error code, set if this function encounters a problem.
    516  * @stable ICU 4.2
    517  */
    518 U_STABLE void U_EXPORT2
    519 uspoof_setAllowedLocales(USpoofChecker *sc, const char *localesList, UErrorCode *status);
    520 
    521 /**
    522  * Get a list of locales for the scripts that are acceptable in strings
    523  *  to be checked.  If no limitations on scripts have been specified,
    524  *  an empty string will be returned.
    525  *
    526  *  uspoof_setAllowedChars() will reset the list of allowed to be empty.
    527  *
    528  *  The format of the returned list is the same as that supplied to
    529  *  uspoof_setAllowedLocales(), but returned list may not be identical
    530  *  to the originally specified string; the string may be reformatted,
    531  *  and information other than languages from
    532  *  the originally specified locales may be omitted.
    533  *
    534  * @param sc           The USpoofChecker
    535  * @param status       The error code, set if this function encounters a problem.
    536  * @return             A string containing a list of  locales corresponding
    537  *                     to the acceptable scripts, formatted like an
    538  *                     HTTP Accept Language value.
    539  *
    540  * @stable ICU 4.2
    541  */
    542 U_STABLE const char * U_EXPORT2
    543 uspoof_getAllowedLocales(USpoofChecker *sc, UErrorCode *status);
    544 
    545 
    546 /**
    547  * Limit the acceptable characters to those specified by a Unicode Set.
    548  *   Any previously specified character limit is
    549  *   is replaced by the new settings.  This includes limits on
    550  *   characters that were set with the uspoof_setAllowedLocales() function.
    551  *
    552  * The USPOOF_CHAR_LIMIT test is automatically enabled for this
    553  * USpoofChecker by this function.
    554  *
    555  * @param sc       The USpoofChecker
    556  * @param chars    A Unicode Set containing the list of
    557  *                 characters that are permitted.  Ownership of the set
    558  *                 remains with the caller.  The incoming set is cloned by
    559  *                 this function, so there are no restrictions on modifying
    560  *                 or deleting the USet after calling this function.
    561  * @param status   The error code, set if this function encounters a problem.
    562  * @stable ICU 4.2
    563  */
    564 U_STABLE void U_EXPORT2
    565 uspoof_setAllowedChars(USpoofChecker *sc, const USet *chars, UErrorCode *status);
    566 
    567 
    568 /**
    569  * Get a USet for the characters permitted in an identifier.
    570  * This corresponds to the limits imposed by the Set Allowed Characters
    571  * functions. Limitations imposed by other checks will not be
    572  * reflected in the set returned by this function.
    573  *
    574  * The returned set will be frozen, meaning that it cannot be modified
    575  * by the caller.
    576  *
    577  * Ownership of the returned set remains with the Spoof Detector.  The
    578  * returned set will become invalid if the spoof detector is closed,
    579  * or if a new set of allowed characters is specified.
    580  *
    581  *
    582  * @param sc       The USpoofChecker
    583  * @param status   The error code, set if this function encounters a problem.
    584  * @return         A USet containing the characters that are permitted by
    585  *                 the USPOOF_CHAR_LIMIT test.
    586  * @stable ICU 4.2
    587  */
    588 U_STABLE const USet * U_EXPORT2
    589 uspoof_getAllowedChars(const USpoofChecker *sc, UErrorCode *status);
    590 
    591 
    592 #if U_SHOW_CPLUSPLUS_API
    593 /**
    594  * Limit the acceptable characters to those specified by a Unicode Set.
    595  *   Any previously specified character limit is
    596  *   is replaced by the new settings.    This includes limits on
    597  *   characters that were set with the uspoof_setAllowedLocales() function.
    598  *
    599  * The USPOOF_CHAR_LIMIT test is automatically enabled for this
    600  * USoofChecker by this function.
    601  *
    602  * @param sc       The USpoofChecker
    603  * @param chars    A Unicode Set containing the list of
    604  *                 characters that are permitted.  Ownership of the set
    605  *                 remains with the caller.  The incoming set is cloned by
    606  *                 this function, so there are no restrictions on modifying
    607  *                 or deleting the UnicodeSet after calling this function.
    608  * @param status   The error code, set if this function encounters a problem.
    609  * @stable ICU 4.2
    610  */
    611 U_STABLE void U_EXPORT2
    612 uspoof_setAllowedUnicodeSet(USpoofChecker *sc, const icu::UnicodeSet *chars, UErrorCode *status);
    613 
    614 
    615 /**
    616  * Get a UnicodeSet for the characters permitted in an identifier.
    617  * This corresponds to the limits imposed by the Set Allowed Characters /
    618  * UnicodeSet functions. Limitations imposed by other checks will not be
    619  * reflected in the set returned by this function.
    620  *
    621  * The returned set will be frozen, meaning that it cannot be modified
    622  * by the caller.
    623  *
    624  * Ownership of the returned set remains with the Spoof Detector.  The
    625  * returned set will become invalid if the spoof detector is closed,
    626  * or if a new set of allowed characters is specified.
    627  *
    628  *
    629  * @param sc       The USpoofChecker
    630  * @param status   The error code, set if this function encounters a problem.
    631  * @return         A UnicodeSet containing the characters that are permitted by
    632  *                 the USPOOF_CHAR_LIMIT test.
    633  * @stable ICU 4.2
    634  */
    635 U_STABLE const icu::UnicodeSet * U_EXPORT2
    636 uspoof_getAllowedUnicodeSet(const USpoofChecker *sc, UErrorCode *status);
    637 #endif
    638 
    639 
    640 /**
    641  * Check the specified string for possible security issues.
    642  * The text to be checked will typically be an identifier of some sort.
    643  * The set of checks to be performed is specified with uspoof_setChecks().
    644  *
    645  * @param sc      The USpoofChecker
    646  * @param id      The identifier to be checked for possible security issues,
    647  *                in UTF-16 format.
    648  * @param length  the length of the string to be checked, expressed in
    649  *                16 bit UTF-16 code units, or -1 if the string is
    650  *                zero terminated.
    651  * @param position      An out parameter.
    652  *                Originally, the index of the first string position that failed a check.
    653  *                Now, always returns zero.
    654  *                This parameter may be null.
    655  * @param status  The error code, set if an error occurred while attempting to
    656  *                perform the check.
    657  *                Spoofing or security issues detected with the input string are
    658  *                not reported here, but through the function's return value.
    659  * @return        An integer value with bits set for any potential security
    660  *                or spoofing issues detected.  The bits are defined by
    661  *                enum USpoofChecks.  (returned_value & USPOOF_ALL_CHECKS)
    662  *                will be zero if the input string passes all of the
    663  *                enabled checks.
    664  * @stable ICU 4.2
    665  */
    666 U_STABLE int32_t U_EXPORT2
    667 uspoof_check(const USpoofChecker *sc,
    668                          const UChar *id, int32_t length,
    669                          int32_t *position,
    670                          UErrorCode *status);
    671 
    672 
    673 /**
    674  * Check the specified string for possible security issues.
    675  * The text to be checked will typically be an identifier of some sort.
    676  * The set of checks to be performed is specified with uspoof_setChecks().
    677  *
    678  * @param sc      The USpoofChecker
    679  * @param id      A identifier to be checked for possible security issues, in UTF8 format.
    680  * @param length  the length of the string to be checked, or -1 if the string is
    681  *                zero terminated.
    682  * @param position      An out parameter.
    683  *                Originally, the index of the first string position that failed a check.
    684  *                Now, always returns zero.
    685  *                This parameter may be null.
    686  *                @deprecated ICU 51
    687  * @param status  The error code, set if an error occurred while attempting to
    688  *                perform the check.
    689  *                Spoofing or security issues detected with the input string are
    690  *                not reported here, but through the function's return value.
    691  *                If the input contains invalid UTF-8 sequences,
    692  *                a status of U_INVALID_CHAR_FOUND will be returned.
    693  * @return        An integer value with bits set for any potential security
    694  *                or spoofing issues detected.  The bits are defined by
    695  *                enum USpoofChecks.  (returned_value & USPOOF_ALL_CHECKS)
    696  *                will be zero if the input string passes all of the
    697  *                enabled checks.
    698  * @stable ICU 4.2
    699  */
    700 U_STABLE int32_t U_EXPORT2
    701 uspoof_checkUTF8(const USpoofChecker *sc,
    702                  const char *id, int32_t length,
    703                  int32_t *position,
    704                  UErrorCode *status);
    705 
    706 
    707 #if U_SHOW_CPLUSPLUS_API
    708 /**
    709  * Check the specified string for possible security issues.
    710  * The text to be checked will typically be an identifier of some sort.
    711  * The set of checks to be performed is specified with uspoof_setChecks().
    712  *
    713  * @param sc      The USpoofChecker
    714  * @param id      A identifier to be checked for possible security issues.
    715  * @param position      An out parameter.
    716  *                Originally, the index of the first string position that failed a check.
    717  *                Now, always returns zero.
    718  *                This parameter may be null.
    719  *                @deprecated ICU 51
    720  * @param status  The error code, set if an error occurred while attempting to
    721  *                perform the check.
    722  *                Spoofing or security issues detected with the input string are
    723  *                not reported here, but through the function's return value.
    724  * @return        An integer value with bits set for any potential security
    725  *                or spoofing issues detected.  The bits are defined by
    726  *                enum USpoofChecks.  (returned_value & USPOOF_ALL_CHECKS)
    727  *                will be zero if the input string passes all of the
    728  *                enabled checks.
    729  * @stable ICU 4.2
    730  */
    731 U_STABLE int32_t U_EXPORT2
    732 uspoof_checkUnicodeString(const USpoofChecker *sc,
    733                           const icu::UnicodeString &id,
    734                           int32_t *position,
    735                           UErrorCode *status);
    736 
    737 #endif
    738 
    739 
    740 /**
    741  * Check the whether two specified strings are visually confusable.
    742  * The types of confusability to be tested - single script, mixed script,
    743  * or whole script - are determined by the check options set for the
    744  * USpoofChecker.
    745  *
    746  * The tests to be performed are controlled by the flags
    747  *   USPOOF_SINGLE_SCRIPT_CONFUSABLE
    748  *   USPOOF_MIXED_SCRIPT_CONFUSABLE
    749  *   USPOOF_WHOLE_SCRIPT_CONFUSABLE
    750  * At least one of these tests must be selected.
    751  *
    752  * USPOOF_ANY_CASE is a modifier for the tests.  Select it if the identifiers
    753  *   may be of mixed case.
    754  * If identifiers are case folded for comparison and
    755  * display to the user, do not select the USPOOF_ANY_CASE option.
    756  *
    757  *
    758  * @param sc      The USpoofChecker
    759  * @param id1     The first of the two identifiers to be compared for
    760  *                confusability.  The strings are in UTF-16 format.
    761  * @param length1 the length of the first identifer, expressed in
    762  *                16 bit UTF-16 code units, or -1 if the string is
    763  *                nul terminated.
    764  * @param id2     The second of the two identifiers to be compared for
    765  *                confusability.  The identifiers are in UTF-16 format.
    766  * @param length2 The length of the second identifiers, expressed in
    767  *                16 bit UTF-16 code units, or -1 if the string is
    768  *                nul terminated.
    769  * @param status  The error code, set if an error occurred while attempting to
    770  *                perform the check.
    771  *                Confusability of the identifiers is not reported here,
    772  *                but through this function's return value.
    773  * @return        An integer value with bit(s) set corresponding to
    774  *                the type of confusability found, as defined by
    775  *                enum USpoofChecks.  Zero is returned if the identifiers
    776  *                are not confusable.
    777  * @stable ICU 4.2
    778  */
    779 U_STABLE int32_t U_EXPORT2
    780 uspoof_areConfusable(const USpoofChecker *sc,
    781                      const UChar *id1, int32_t length1,
    782                      const UChar *id2, int32_t length2,
    783                      UErrorCode *status);
    784 
    785 
    786 
    787 /**
    788  * Check the whether two specified strings are visually confusable.
    789  * The types of confusability to be tested - single script, mixed script,
    790  * or whole script - are determined by the check options set for the
    791  * USpoofChecker.
    792  *
    793  * @param sc      The USpoofChecker
    794  * @param id1     The first of the two identifiers to be compared for
    795  *                confusability.  The strings are in UTF-8 format.
    796  * @param length1 the length of the first identifiers, in bytes, or -1
    797  *                if the string is nul terminated.
    798  * @param id2     The second of the two identifiers to be compared for
    799  *                confusability.  The strings are in UTF-8 format.
    800  * @param length2 The length of the second string in bytes, or -1
    801  *                if the string is nul terminated.
    802  * @param status  The error code, set if an error occurred while attempting to
    803  *                perform the check.
    804  *                Confusability of the strings is not reported here,
    805  *                but through this function's return value.
    806  * @return        An integer value with bit(s) set corresponding to
    807  *                the type of confusability found, as defined by
    808  *                enum USpoofChecks.  Zero is returned if the strings
    809  *                are not confusable.
    810  * @stable ICU 4.2
    811  */
    812 U_STABLE int32_t U_EXPORT2
    813 uspoof_areConfusableUTF8(const USpoofChecker *sc,
    814                          const char *id1, int32_t length1,
    815                          const char *id2, int32_t length2,
    816                          UErrorCode *status);
    817 
    818 
    819 
    820 
    821 #if U_SHOW_CPLUSPLUS_API
    822 /**
    823  * Check the whether two specified strings are visually confusable.
    824  * The types of confusability to be tested - single script, mixed script,
    825  * or whole script - are determined by the check options set for the
    826  * USpoofChecker.
    827  *
    828  * @param sc      The USpoofChecker
    829  * @param id1     The first of the two identifiers to be compared for
    830  *                confusability.  The strings are in UTF-8 format.
    831  * @param id2     The second of the two identifiers to be compared for
    832  *                confusability.  The strings are in UTF-8 format.
    833  * @param status  The error code, set if an error occurred while attempting to
    834  *                perform the check.
    835  *                Confusability of the identifiers is not reported here,
    836  *                but through this function's return value.
    837  * @return        An integer value with bit(s) set corresponding to
    838  *                the type of confusability found, as defined by
    839  *                enum USpoofChecks.  Zero is returned if the identifiers
    840  *                are not confusable.
    841  * @stable ICU 4.2
    842  */
    843 U_STABLE int32_t U_EXPORT2
    844 uspoof_areConfusableUnicodeString(const USpoofChecker *sc,
    845                                   const icu::UnicodeString &s1,
    846                                   const icu::UnicodeString &s2,
    847                                   UErrorCode *status);
    848 #endif
    849 
    850 
    851 /**
    852   *  Get the "skeleton" for an identifier.
    853   *  Skeletons are a transformation of the input identifier;
    854   *  Two identifiers are confusable if their skeletons are identical.
    855   *  See Unicode UAX #39 for additional information.
    856   *
    857   *  Using skeletons directly makes it possible to quickly check
    858   *  whether an identifier is confusable with any of some large
    859   *  set of existing identifiers, by creating an efficiently
    860   *  searchable collection of the skeletons.
    861   *
    862   * @param sc      The USpoofChecker
    863   * @param type    The type of skeleton, corresponding to which
    864   *                of the Unicode confusable data tables to use.
    865   *                The default is Mixed-Script, Lowercase.
    866   *                Allowed options are USPOOF_SINGLE_SCRIPT_CONFUSABLE and
    867   *                USPOOF_ANY_CASE_CONFUSABLE.  The two flags may be ORed.
    868   * @param id      The input identifier whose skeleton will be computed.
    869   * @param length  The length of the input identifier, expressed in 16 bit
    870   *                UTF-16 code units, or -1 if the string is zero terminated.
    871   * @param dest    The output buffer, to receive the skeleton string.
    872   * @param destCapacity  The length of the output buffer, in 16 bit units.
    873   *                The destCapacity may be zero, in which case the function will
    874   *                return the actual length of the skeleton.
    875   * @param status  The error code, set if an error occurred while attempting to
    876   *                perform the check.
    877   * @return        The length of the skeleton string.  The returned length
    878   *                is always that of the complete skeleton, even when the
    879   *                supplied buffer is too small (or of zero length)
    880   *
    881   * @stable ICU 4.2
    882   */
    883 U_STABLE int32_t U_EXPORT2
    884 uspoof_getSkeleton(const USpoofChecker *sc,
    885                    uint32_t type,
    886                    const UChar *id,  int32_t length,
    887                    UChar *dest, int32_t destCapacity,
    888                    UErrorCode *status);
    889 
    890 /**
    891   *  Get the "skeleton" for an identifier.
    892   *  Skeletons are a transformation of the input identifier;
    893   *  Two identifiers are confusable if their skeletons are identical.
    894   *  See Unicode UAX #39 for additional information.
    895   *
    896   *  Using skeletons directly makes it possible to quickly check
    897   *  whether an identifier is confusable with any of some large
    898   *  set of existing identifiers, by creating an efficiently
    899   *  searchable collection of the skeletons.
    900   *
    901   * @param sc      The USpoofChecker
    902   * @param type    The type of skeleton, corresponding to which
    903   *                of the Unicode confusable data tables to use.
    904   *                The default is Mixed-Script, Lowercase.
    905   *                Allowed options are USPOOF_SINGLE_SCRIPT_CONFUSABLE and
    906   *                USPOOF_ANY_CASE.  The two flags may be ORed.
    907   * @param id      The UTF-8 format identifier whose skeleton will be computed.
    908   * @param length  The length of the input string, in bytes,
    909   *                or -1 if the string is zero terminated.
    910   * @param dest    The output buffer, to receive the skeleton string.
    911   * @param destCapacity  The length of the output buffer, in bytes.
    912   *                The destCapacity may be zero, in which case the function will
    913   *                return the actual length of the skeleton.
    914   * @param status  The error code, set if an error occurred while attempting to
    915   *                perform the check.  Possible Errors include U_INVALID_CHAR_FOUND
    916   *                   for invalid UTF-8 sequences, and
    917   *                   U_BUFFER_OVERFLOW_ERROR if the destination buffer is too small
    918   *                   to hold the complete skeleton.
    919   * @return        The length of the skeleton string, in bytes.  The returned length
    920   *                is always that of the complete skeleton, even when the
    921   *                supplied buffer is too small (or of zero length)
    922   *
    923   * @stable ICU 4.2
    924   */
    925 U_STABLE int32_t U_EXPORT2
    926 uspoof_getSkeletonUTF8(const USpoofChecker *sc,
    927                        uint32_t type,
    928                        const char *id,  int32_t length,
    929                        char *dest, int32_t destCapacity,
    930                        UErrorCode *status);
    931 
    932 #if U_SHOW_CPLUSPLUS_API
    933 /**
    934   *  Get the "skeleton" for an identifier.
    935   *  Skeletons are a transformation of the input identifier;
    936   *  Two identifiers are confusable if their skeletons are identical.
    937   *  See Unicode UAX #39 for additional information.
    938   *
    939   *  Using skeletons directly makes it possible to quickly check
    940   *  whether an identifier is confusable with any of some large
    941   *  set of existing identifiers, by creating an efficiently
    942   *  searchable collection of the skeletons.
    943   *
    944   * @param sc      The USpoofChecker.
    945   * @param type    The type of skeleton, corresponding to which
    946   *                of the Unicode confusable data tables to use.
    947   *                The default is Mixed-Script, Lowercase.
    948   *                Allowed options are USPOOF_SINGLE_SCRIPT_CONFUSABLE and
    949   *                USPOOF_ANY_CASE_CONFUSABLE.  The two flags may be ORed.
    950   * @param id      The input identifier whose skeleton will be computed.
    951   * @param dest    The output identifier, to receive the skeleton string.
    952   * @param status  The error code, set if an error occurred while attempting to
    953   *                perform the check.
    954   * @return        A reference to the destination (skeleton) string.
    955   *
    956   * @stable ICU 4.2
    957   */
    958 U_I18N_API icu::UnicodeString & U_EXPORT2
    959 uspoof_getSkeletonUnicodeString(const USpoofChecker *sc,
    960                                 uint32_t type,
    961                                 const icu::UnicodeString &id,
    962                                 icu::UnicodeString &dest,
    963                                 UErrorCode *status);
    964 #endif   /* U_SHOW_CPLUSPLUS_API */
    965 
    966 
    967 #ifndef U_HIDE_DRAFT_API
    968 /**
    969   * Get the set of Candidate Characters for Inclusion in Identifiers, as defined
    970   * in Unicode UAX #31, http://www.unicode.org/reports/tr31/#Table_Candidate_Characters_for_Inclusion_in_Identifiers
    971   *
    972   * The returned set is frozen. Ownership of the set remains with the ICU library; it must not
    973   * be deleted by the caller.
    974   *
    975   * @param status The error code, set if a problem occurs while creating the set.
    976   *
    977   * @draft ICU 51
    978   */
    979 U_DRAFT const USet * U_EXPORT2
    980 uspoof_getInclusionSet(UErrorCode *status);
    981 
    982 /**
    983   * Get the set of characters from Recommended Scripts for Inclusion in Identifiers, as defined
    984   * in Unicode UAX #31, http://www.unicode.org/reports/tr31/#Table_Recommended_Scripts
    985   *
    986   * The returned set is frozen. Ownership of the set remains with the ICU library; it must not
    987   * be deleted by the caller.
    988   *
    989   * @param status The error code, set if a problem occurs while creating the set.
    990   *
    991   * @draft ICU 51
    992   */
    993 U_DRAFT const USet * U_EXPORT2
    994 uspoof_getRecommendedSet(UErrorCode *status);
    995 
    996 #if U_SHOW_CPLUSPLUS_API
    997 
    998 /**
    999   * Get the set of Candidate Characters for Inclusion in Identifiers, as defined
   1000   * in Unicode UAX #31, http://www.unicode.org/reports/tr31/#Table_Candidate_Characters_for_Inclusion_in_Identifiers
   1001   *
   1002   * The returned set is frozen. Ownership of the set remains with the ICU library; it must not
   1003   * be deleted by the caller.
   1004   *
   1005   * @param status The error code, set if a problem occurs while creating the set.
   1006   *
   1007   * @draft ICU 51
   1008   */
   1009 U_DRAFT const icu::UnicodeSet * U_EXPORT2
   1010 uspoof_getInclusionUnicodeSet(UErrorCode *status);
   1011 
   1012 /**
   1013   * Get the set of characters from Recommended Scripts for Inclusion in Identifiers, as defined
   1014   * in Unicode UAX #31, http://www.unicode.org/reports/tr31/#Table_Recommended_Scripts
   1015   *
   1016   * The returned set is frozen. Ownership of the set remains with the ICU library; it must not
   1017   * be deleted by the caller.
   1018   *
   1019   * @param status The error code, set if a problem occurs while creating the set.
   1020   *
   1021   * @draft ICU 51
   1022   */
   1023 U_DRAFT const icu::UnicodeSet * U_EXPORT2
   1024 uspoof_getRecommendedUnicodeSet(UErrorCode *status);
   1025 
   1026 #endif /* U_SHOW_CPLUSPLUS_API */
   1027 #endif /* U_HIDE_DRAFT_API */
   1028 
   1029 /**
   1030  * Serialize the data for a spoof detector into a chunk of memory.
   1031  * The flattened spoof detection tables can later be used to efficiently
   1032  * instantiate a new Spoof Detector.
   1033  *
   1034  * The serialized spoof checker includes only the data compiled from the
   1035  * Unicode data tables by uspoof_openFromSource(); it does not include
   1036  * include any other state or configuration that may have been set.
   1037  *
   1038  * @param sc   the Spoof Detector whose data is to be serialized.
   1039  * @param data a pointer to 32-bit-aligned memory to be filled with the data,
   1040  *             can be NULL if capacity==0
   1041  * @param capacity the number of bytes available at data,
   1042  *                 or 0 for preflighting
   1043  * @param status an in/out ICU UErrorCode; possible errors include:
   1044  * - U_BUFFER_OVERFLOW_ERROR if the data storage block is too small for serialization
   1045  * - U_ILLEGAL_ARGUMENT_ERROR  the data or capacity parameters are bad
   1046  * @return the number of bytes written or needed for the spoof data
   1047  *
   1048  * @see utrie2_openFromSerialized()
   1049  * @stable ICU 4.2
   1050  */
   1051 U_STABLE int32_t U_EXPORT2
   1052 uspoof_serialize(USpoofChecker *sc,
   1053                  void *data, int32_t capacity,
   1054                  UErrorCode *status);
   1055 
   1056 
   1057 #endif
   1058 
   1059 #endif   /* USPOOF_H */
   1060