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      1 /*
      2  **********************************************************************
      3  *   Copyright (C) 1999-2011, International Business Machines
      4  *   Corporation and others.  All Rights Reserved.
      5  **********************************************************************
      6  *   Date        Name        Description
      7  *   11/17/99    aliu        Creation.
      8  **********************************************************************
      9  */
     10 
     11 #include "unicode/utypes.h"
     12 
     13 #if !UCONFIG_NO_TRANSLITERATION
     14 
     15 #include "unicode/uobject.h"
     16 #include "unicode/parseerr.h"
     17 #include "unicode/parsepos.h"
     18 #include "unicode/putil.h"
     19 #include "unicode/uchar.h"
     20 #include "unicode/ustring.h"
     21 #include "unicode/uniset.h"
     22 #include "cstring.h"
     23 #include "funcrepl.h"
     24 #include "hash.h"
     25 #include "quant.h"
     26 #include "rbt.h"
     27 #include "rbt_data.h"
     28 #include "rbt_pars.h"
     29 #include "rbt_rule.h"
     30 #include "strmatch.h"
     31 #include "strrepl.h"
     32 #include "unicode/symtable.h"
     33 #include "tridpars.h"
     34 #include "uvector.h"
     35 #include "hash.h"
     36 #include "patternprops.h"
     37 #include "util.h"
     38 #include "cmemory.h"
     39 #include "uprops.h"
     40 #include "putilimp.h"
     41 
     42 // Operators
     43 #define VARIABLE_DEF_OP ((UChar)0x003D) /*=*/
     44 #define FORWARD_RULE_OP ((UChar)0x003E) /*>*/
     45 #define REVERSE_RULE_OP ((UChar)0x003C) /*<*/
     46 #define FWDREV_RULE_OP  ((UChar)0x007E) /*~*/ // internal rep of <> op
     47 
     48 // Other special characters
     49 #define QUOTE             ((UChar)0x0027) /*'*/
     50 #define ESCAPE            ((UChar)0x005C) /*\*/
     51 #define END_OF_RULE       ((UChar)0x003B) /*;*/
     52 #define RULE_COMMENT_CHAR ((UChar)0x0023) /*#*/
     53 
     54 #define SEGMENT_OPEN       ((UChar)0x0028) /*(*/
     55 #define SEGMENT_CLOSE      ((UChar)0x0029) /*)*/
     56 #define CONTEXT_ANTE       ((UChar)0x007B) /*{*/
     57 #define CONTEXT_POST       ((UChar)0x007D) /*}*/
     58 #define CURSOR_POS         ((UChar)0x007C) /*|*/
     59 #define CURSOR_OFFSET      ((UChar)0x0040) /*@*/
     60 #define ANCHOR_START       ((UChar)0x005E) /*^*/
     61 #define KLEENE_STAR        ((UChar)0x002A) /***/
     62 #define ONE_OR_MORE        ((UChar)0x002B) /*+*/
     63 #define ZERO_OR_ONE        ((UChar)0x003F) /*?*/
     64 
     65 #define DOT                ((UChar)46)     /*.*/
     66 
     67 static const UChar DOT_SET[] = { // "[^[:Zp:][:Zl:]\r\n$]";
     68     91, 94, 91, 58, 90, 112, 58, 93, 91, 58, 90,
     69     108, 58, 93, 92, 114, 92, 110, 36, 93, 0
     70 };
     71 
     72 // A function is denoted &Source-Target/Variant(text)
     73 #define FUNCTION           ((UChar)38)     /*&*/
     74 
     75 // Aliases for some of the syntax characters. These are provided so
     76 // transliteration rules can be expressed in XML without clashing with
     77 // XML syntax characters '<', '>', and '&'.
     78 #define ALT_REVERSE_RULE_OP ((UChar)0x2190) // Left Arrow
     79 #define ALT_FORWARD_RULE_OP ((UChar)0x2192) // Right Arrow
     80 #define ALT_FWDREV_RULE_OP  ((UChar)0x2194) // Left Right Arrow
     81 #define ALT_FUNCTION        ((UChar)0x2206) // Increment (~Greek Capital Delta)
     82 
     83 // Special characters disallowed at the top level
     84 static const UChar ILLEGAL_TOP[] = {41,0}; // ")"
     85 
     86 // Special characters disallowed within a segment
     87 static const UChar ILLEGAL_SEG[] = {123,125,124,64,0}; // "{}|@"
     88 
     89 // Special characters disallowed within a function argument
     90 static const UChar ILLEGAL_FUNC[] = {94,40,46,42,43,63,123,125,124,64,0}; // "^(.*+?{}|@"
     91 
     92 // By definition, the ANCHOR_END special character is a
     93 // trailing SymbolTable.SYMBOL_REF character.
     94 // private static final char ANCHOR_END       = '$';
     95 
     96 static const UChar gOPERATORS[] = { // "=><"
     97     VARIABLE_DEF_OP, FORWARD_RULE_OP, REVERSE_RULE_OP,
     98     ALT_FORWARD_RULE_OP, ALT_REVERSE_RULE_OP, ALT_FWDREV_RULE_OP,
     99     0
    100 };
    101 
    102 static const UChar HALF_ENDERS[] = { // "=><;"
    103     VARIABLE_DEF_OP, FORWARD_RULE_OP, REVERSE_RULE_OP,
    104     ALT_FORWARD_RULE_OP, ALT_REVERSE_RULE_OP, ALT_FWDREV_RULE_OP,
    105     END_OF_RULE,
    106     0
    107 };
    108 
    109 // These are also used in Transliterator::toRules()
    110 static const int32_t ID_TOKEN_LEN = 2;
    111 static const UChar   ID_TOKEN[]   = { 0x3A, 0x3A }; // ':', ':'
    112 
    113 /*
    114 commented out until we do real ::BEGIN/::END functionality
    115 static const int32_t BEGIN_TOKEN_LEN = 5;
    116 static const UChar BEGIN_TOKEN[] = { 0x42, 0x45, 0x47, 0x49, 0x4e }; // 'BEGIN'
    117 
    118 static const int32_t END_TOKEN_LEN = 3;
    119 static const UChar END_TOKEN[] = { 0x45, 0x4e, 0x44 }; // 'END'
    120 */
    121 
    122 U_NAMESPACE_BEGIN
    123 
    124 //----------------------------------------------------------------------
    125 // BEGIN ParseData
    126 //----------------------------------------------------------------------
    127 
    128 /**
    129  * This class implements the SymbolTable interface.  It is used
    130  * during parsing to give UnicodeSet access to variables that
    131  * have been defined so far.  Note that it uses variablesVector,
    132  * _not_ data.setVariables.
    133  */
    134 class ParseData : public UMemory, public SymbolTable {
    135 public:
    136     const TransliterationRuleData* data; // alias
    137 
    138     const UVector* variablesVector; // alias
    139 
    140     const Hashtable* variableNames; // alias
    141 
    142     ParseData(const TransliterationRuleData* data = 0,
    143               const UVector* variablesVector = 0,
    144               const Hashtable* variableNames = 0);
    145 
    146     virtual const UnicodeString* lookup(const UnicodeString& s) const;
    147 
    148     virtual const UnicodeFunctor* lookupMatcher(UChar32 ch) const;
    149 
    150     virtual UnicodeString parseReference(const UnicodeString& text,
    151                                          ParsePosition& pos, int32_t limit) const;
    152     /**
    153      * Return true if the given character is a matcher standin or a plain
    154      * character (non standin).
    155      */
    156     UBool isMatcher(UChar32 ch);
    157 
    158     /**
    159      * Return true if the given character is a replacer standin or a plain
    160      * character (non standin).
    161      */
    162     UBool isReplacer(UChar32 ch);
    163 
    164 private:
    165     ParseData(const ParseData &other); // forbid copying of this class
    166     ParseData &operator=(const ParseData &other); // forbid copying of this class
    167 };
    168 
    169 ParseData::ParseData(const TransliterationRuleData* d,
    170                      const UVector* sets,
    171                      const Hashtable* vNames) :
    172     data(d), variablesVector(sets), variableNames(vNames) {}
    173 
    174 /**
    175  * Implement SymbolTable API.
    176  */
    177 const UnicodeString* ParseData::lookup(const UnicodeString& name) const {
    178     return (const UnicodeString*) variableNames->get(name);
    179 }
    180 
    181 /**
    182  * Implement SymbolTable API.
    183  */
    184 const UnicodeFunctor* ParseData::lookupMatcher(UChar32 ch) const {
    185     // Note that we cannot use data.lookupSet() because the
    186     // set array has not been constructed yet.
    187     const UnicodeFunctor* set = NULL;
    188     int32_t i = ch - data->variablesBase;
    189     if (i >= 0 && i < variablesVector->size()) {
    190         int32_t i = ch - data->variablesBase;
    191         set = (i < variablesVector->size()) ?
    192             (UnicodeFunctor*) variablesVector->elementAt(i) : 0;
    193     }
    194     return set;
    195 }
    196 
    197 /**
    198  * Implement SymbolTable API.  Parse out a symbol reference
    199  * name.
    200  */
    201 UnicodeString ParseData::parseReference(const UnicodeString& text,
    202                                         ParsePosition& pos, int32_t limit) const {
    203     int32_t start = pos.getIndex();
    204     int32_t i = start;
    205     UnicodeString result;
    206     while (i < limit) {
    207         UChar c = text.charAt(i);
    208         if ((i==start && !u_isIDStart(c)) || !u_isIDPart(c)) {
    209             break;
    210         }
    211         ++i;
    212     }
    213     if (i == start) { // No valid name chars
    214         return result; // Indicate failure with empty string
    215     }
    216     pos.setIndex(i);
    217     text.extractBetween(start, i, result);
    218     return result;
    219 }
    220 
    221 UBool ParseData::isMatcher(UChar32 ch) {
    222     // Note that we cannot use data.lookup() because the
    223     // set array has not been constructed yet.
    224     int32_t i = ch - data->variablesBase;
    225     if (i >= 0 && i < variablesVector->size()) {
    226         UnicodeFunctor *f = (UnicodeFunctor*) variablesVector->elementAt(i);
    227         return f != NULL && f->toMatcher() != NULL;
    228     }
    229     return TRUE;
    230 }
    231 
    232 /**
    233  * Return true if the given character is a replacer standin or a plain
    234  * character (non standin).
    235  */
    236 UBool ParseData::isReplacer(UChar32 ch) {
    237     // Note that we cannot use data.lookup() because the
    238     // set array has not been constructed yet.
    239     int i = ch - data->variablesBase;
    240     if (i >= 0 && i < variablesVector->size()) {
    241         UnicodeFunctor *f = (UnicodeFunctor*) variablesVector->elementAt(i);
    242         return f != NULL && f->toReplacer() != NULL;
    243     }
    244     return TRUE;
    245 }
    246 
    247 //----------------------------------------------------------------------
    248 // BEGIN RuleHalf
    249 //----------------------------------------------------------------------
    250 
    251 /**
    252  * A class representing one side of a rule.  This class knows how to
    253  * parse half of a rule.  It is tightly coupled to the method
    254  * RuleBasedTransliterator.Parser.parseRule().
    255  */
    256 class RuleHalf : public UMemory {
    257 
    258 public:
    259 
    260     UnicodeString text;
    261 
    262     int32_t cursor; // position of cursor in text
    263     int32_t ante;   // position of ante context marker '{' in text
    264     int32_t post;   // position of post context marker '}' in text
    265 
    266     // Record the offset to the cursor either to the left or to the
    267     // right of the key.  This is indicated by characters on the output
    268     // side that allow the cursor to be positioned arbitrarily within
    269     // the matching text.  For example, abc{def} > | @@@ xyz; changes
    270     // def to xyz and moves the cursor to before abc.  Offset characters
    271     // must be at the start or end, and they cannot move the cursor past
    272     // the ante- or postcontext text.  Placeholders are only valid in
    273     // output text.  The length of the ante and post context is
    274     // determined at runtime, because of supplementals and quantifiers.
    275     int32_t cursorOffset; // only nonzero on output side
    276 
    277     // Position of first CURSOR_OFFSET on _right_.  This will be -1
    278     // for |@, -2 for |@@, etc., and 1 for @|, 2 for @@|, etc.
    279     int32_t cursorOffsetPos;
    280 
    281     UBool anchorStart;
    282     UBool anchorEnd;
    283 
    284     /**
    285      * The segment number from 1..n of the next '(' we see
    286      * during parsing; 1-based.
    287      */
    288     int32_t nextSegmentNumber;
    289 
    290     TransliteratorParser& parser;
    291 
    292     //--------------------------------------------------
    293     // Methods
    294 
    295     RuleHalf(TransliteratorParser& parser);
    296     ~RuleHalf();
    297 
    298     int32_t parse(const UnicodeString& rule, int32_t pos, int32_t limit, UErrorCode& status);
    299 
    300     int32_t parseSection(const UnicodeString& rule, int32_t pos, int32_t limit,
    301                          UnicodeString& buf,
    302                          const UnicodeString& illegal,
    303                          UBool isSegment,
    304                          UErrorCode& status);
    305 
    306     /**
    307      * Remove context.
    308      */
    309     void removeContext();
    310 
    311     /**
    312      * Return true if this half looks like valid output, that is, does not
    313      * contain quantifiers or other special input-only elements.
    314      */
    315     UBool isValidOutput(TransliteratorParser& parser);
    316 
    317     /**
    318      * Return true if this half looks like valid input, that is, does not
    319      * contain functions or other special output-only elements.
    320      */
    321     UBool isValidInput(TransliteratorParser& parser);
    322 
    323     int syntaxError(UErrorCode code,
    324                     const UnicodeString& rule,
    325                     int32_t start,
    326                     UErrorCode& status) {
    327         return parser.syntaxError(code, rule, start, status);
    328     }
    329 
    330 private:
    331     // Disallowed methods; no impl.
    332     RuleHalf(const RuleHalf&);
    333     RuleHalf& operator=(const RuleHalf&);
    334 };
    335 
    336 RuleHalf::RuleHalf(TransliteratorParser& p) :
    337     parser(p)
    338 {
    339     cursor = -1;
    340     ante = -1;
    341     post = -1;
    342     cursorOffset = 0;
    343     cursorOffsetPos = 0;
    344     anchorStart = anchorEnd = FALSE;
    345     nextSegmentNumber = 1;
    346 }
    347 
    348 RuleHalf::~RuleHalf() {
    349 }
    350 
    351 /**
    352  * Parse one side of a rule, stopping at either the limit,
    353  * the END_OF_RULE character, or an operator.
    354  * @return the index after the terminating character, or
    355  * if limit was reached, limit
    356  */
    357 int32_t RuleHalf::parse(const UnicodeString& rule, int32_t pos, int32_t limit, UErrorCode& status) {
    358     int32_t start = pos;
    359     text.truncate(0);
    360     pos = parseSection(rule, pos, limit, text, ILLEGAL_TOP, FALSE, status);
    361 
    362     if (cursorOffset > 0 && cursor != cursorOffsetPos) {
    363         return syntaxError(U_MISPLACED_CURSOR_OFFSET, rule, start, status);
    364     }
    365 
    366     return pos;
    367 }
    368 
    369 /**
    370  * Parse a section of one side of a rule, stopping at either
    371  * the limit, the END_OF_RULE character, an operator, or a
    372  * segment close character.  This method parses both a
    373  * top-level rule half and a segment within such a rule half.
    374  * It calls itself recursively to parse segments and nested
    375  * segments.
    376  * @param buf buffer into which to accumulate the rule pattern
    377  * characters, either literal characters from the rule or
    378  * standins for UnicodeMatcher objects including segments.
    379  * @param illegal the set of special characters that is illegal during
    380  * this parse.
    381  * @param isSegment if true, then we've already seen a '(' and
    382  * pos on entry points right after it.  Accumulate everything
    383  * up to the closing ')', put it in a segment matcher object,
    384  * generate a standin for it, and add the standin to buf.  As
    385  * a side effect, update the segments vector with a reference
    386  * to the segment matcher.  This works recursively for nested
    387  * segments.  If isSegment is false, just accumulate
    388  * characters into buf.
    389  * @return the index after the terminating character, or
    390  * if limit was reached, limit
    391  */
    392 int32_t RuleHalf::parseSection(const UnicodeString& rule, int32_t pos, int32_t limit,
    393                                UnicodeString& buf,
    394                                const UnicodeString& illegal,
    395                                UBool isSegment, UErrorCode& status) {
    396     int32_t start = pos;
    397     ParsePosition pp;
    398     UnicodeString scratch;
    399     UBool done = FALSE;
    400     int32_t quoteStart = -1; // Most recent 'single quoted string'
    401     int32_t quoteLimit = -1;
    402     int32_t varStart = -1; // Most recent $variableReference
    403     int32_t varLimit = -1;
    404     int32_t bufStart = buf.length();
    405 
    406     while (pos < limit && !done) {
    407         // Since all syntax characters are in the BMP, fetching
    408         // 16-bit code units suffices here.
    409         UChar c = rule.charAt(pos++);
    410         if (PatternProps::isWhiteSpace(c)) {
    411             // Ignore whitespace.  Note that this is not Unicode
    412             // spaces, but Java spaces -- a subset, representing
    413             // whitespace likely to be seen in code.
    414             continue;
    415         }
    416         if (u_strchr(HALF_ENDERS, c) != NULL) {
    417             if (isSegment) {
    418                 // Unclosed segment
    419                 return syntaxError(U_UNCLOSED_SEGMENT, rule, start, status);
    420             }
    421             break;
    422         }
    423         if (anchorEnd) {
    424             // Text after a presumed end anchor is a syntax err
    425             return syntaxError(U_MALFORMED_VARIABLE_REFERENCE, rule, start, status);
    426         }
    427         if (UnicodeSet::resemblesPattern(rule, pos-1)) {
    428             pp.setIndex(pos-1); // Backup to opening '['
    429             buf.append(parser.parseSet(rule, pp, status));
    430             if (U_FAILURE(status)) {
    431                 return syntaxError(U_MALFORMED_SET, rule, start, status);
    432             }
    433             pos = pp.getIndex();
    434             continue;
    435         }
    436         // Handle escapes
    437         if (c == ESCAPE) {
    438             if (pos == limit) {
    439                 return syntaxError(U_TRAILING_BACKSLASH, rule, start, status);
    440             }
    441             UChar32 escaped = rule.unescapeAt(pos); // pos is already past '\\'
    442             if (escaped == (UChar32) -1) {
    443                 return syntaxError(U_MALFORMED_UNICODE_ESCAPE, rule, start, status);
    444             }
    445             if (!parser.checkVariableRange(escaped)) {
    446                 return syntaxError(U_VARIABLE_RANGE_OVERLAP, rule, start, status);
    447             }
    448             buf.append(escaped);
    449             continue;
    450         }
    451         // Handle quoted matter
    452         if (c == QUOTE) {
    453             int32_t iq = rule.indexOf(QUOTE, pos);
    454             if (iq == pos) {
    455                 buf.append(c); // Parse [''] outside quotes as [']
    456                 ++pos;
    457             } else {
    458                 /* This loop picks up a run of quoted text of the
    459                  * form 'aaaa' each time through.  If this run
    460                  * hasn't really ended ('aaaa''bbbb') then it keeps
    461                  * looping, each time adding on a new run.  When it
    462                  * reaches the final quote it breaks.
    463                  */
    464                 quoteStart = buf.length();
    465                 for (;;) {
    466                     if (iq < 0) {
    467                         return syntaxError(U_UNTERMINATED_QUOTE, rule, start, status);
    468                     }
    469                     scratch.truncate(0);
    470                     rule.extractBetween(pos, iq, scratch);
    471                     buf.append(scratch);
    472                     pos = iq+1;
    473                     if (pos < limit && rule.charAt(pos) == QUOTE) {
    474                         // Parse [''] inside quotes as [']
    475                         iq = rule.indexOf(QUOTE, pos+1);
    476                         // Continue looping
    477                     } else {
    478                         break;
    479                     }
    480                 }
    481                 quoteLimit = buf.length();
    482 
    483                 for (iq=quoteStart; iq<quoteLimit; ++iq) {
    484                     if (!parser.checkVariableRange(buf.charAt(iq))) {
    485                         return syntaxError(U_VARIABLE_RANGE_OVERLAP, rule, start, status);
    486                     }
    487                 }
    488             }
    489             continue;
    490         }
    491 
    492         if (!parser.checkVariableRange(c)) {
    493             return syntaxError(U_VARIABLE_RANGE_OVERLAP, rule, start, status);
    494         }
    495 
    496         if (illegal.indexOf(c) >= 0) {
    497             syntaxError(U_ILLEGAL_CHARACTER, rule, start, status);
    498         }
    499 
    500         switch (c) {
    501 
    502         //------------------------------------------------------
    503         // Elements allowed within and out of segments
    504         //------------------------------------------------------
    505         case ANCHOR_START:
    506             if (buf.length() == 0 && !anchorStart) {
    507                 anchorStart = TRUE;
    508             } else {
    509               return syntaxError(U_MISPLACED_ANCHOR_START,
    510                                  rule, start, status);
    511             }
    512           break;
    513         case SEGMENT_OPEN:
    514             {
    515                 // bufSegStart is the offset in buf to the first
    516                 // character of the segment we are parsing.
    517                 int32_t bufSegStart = buf.length();
    518 
    519                 // Record segment number now, since nextSegmentNumber
    520                 // will be incremented during the call to parseSection
    521                 // if there are nested segments.
    522                 int32_t segmentNumber = nextSegmentNumber++; // 1-based
    523 
    524                 // Parse the segment
    525                 pos = parseSection(rule, pos, limit, buf, ILLEGAL_SEG, TRUE, status);
    526 
    527                 // After parsing a segment, the relevant characters are
    528                 // in buf, starting at offset bufSegStart.  Extract them
    529                 // into a string matcher, and replace them with a
    530                 // standin for that matcher.
    531                 StringMatcher* m =
    532                     new StringMatcher(buf, bufSegStart, buf.length(),
    533                                       segmentNumber, *parser.curData);
    534                 if (m == NULL) {
    535                     return syntaxError(U_MEMORY_ALLOCATION_ERROR, rule, start, status);
    536                 }
    537 
    538                 // Record and associate object and segment number
    539                 parser.setSegmentObject(segmentNumber, m, status);
    540                 buf.truncate(bufSegStart);
    541                 buf.append(parser.getSegmentStandin(segmentNumber, status));
    542             }
    543             break;
    544         case FUNCTION:
    545         case ALT_FUNCTION:
    546             {
    547                 int32_t iref = pos;
    548                 TransliteratorIDParser::SingleID* single =
    549                     TransliteratorIDParser::parseFilterID(rule, iref);
    550                 // The next character MUST be a segment open
    551                 if (single == NULL ||
    552                     !ICU_Utility::parseChar(rule, iref, SEGMENT_OPEN)) {
    553                     return syntaxError(U_INVALID_FUNCTION, rule, start, status);
    554                 }
    555 
    556                 Transliterator *t = single->createInstance();
    557                 delete single;
    558                 if (t == NULL) {
    559                     return syntaxError(U_INVALID_FUNCTION, rule, start, status);
    560                 }
    561 
    562                 // bufSegStart is the offset in buf to the first
    563                 // character of the segment we are parsing.
    564                 int32_t bufSegStart = buf.length();
    565 
    566                 // Parse the segment
    567                 pos = parseSection(rule, iref, limit, buf, ILLEGAL_FUNC, TRUE, status);
    568 
    569                 // After parsing a segment, the relevant characters are
    570                 // in buf, starting at offset bufSegStart.
    571                 UnicodeString output;
    572                 buf.extractBetween(bufSegStart, buf.length(), output);
    573                 FunctionReplacer *r =
    574                     new FunctionReplacer(t, new StringReplacer(output, parser.curData));
    575                 if (r == NULL) {
    576                     return syntaxError(U_MEMORY_ALLOCATION_ERROR, rule, start, status);
    577                 }
    578 
    579                 // Replace the buffer contents with a stand-in
    580                 buf.truncate(bufSegStart);
    581                 buf.append(parser.generateStandInFor(r, status));
    582             }
    583             break;
    584         case SymbolTable::SYMBOL_REF:
    585             // Handle variable references and segment references "$1" .. "$9"
    586             {
    587                 // A variable reference must be followed immediately
    588                 // by a Unicode identifier start and zero or more
    589                 // Unicode identifier part characters, or by a digit
    590                 // 1..9 if it is a segment reference.
    591                 if (pos == limit) {
    592                     // A variable ref character at the end acts as
    593                     // an anchor to the context limit, as in perl.
    594                     anchorEnd = TRUE;
    595                     break;
    596                 }
    597                 // Parse "$1" "$2" .. "$9" .. (no upper limit)
    598                 c = rule.charAt(pos);
    599                 int32_t r = u_digit(c, 10);
    600                 if (r >= 1 && r <= 9) {
    601                     r = ICU_Utility::parseNumber(rule, pos, 10);
    602                     if (r < 0) {
    603                         return syntaxError(U_UNDEFINED_SEGMENT_REFERENCE,
    604                                            rule, start, status);
    605                     }
    606                     buf.append(parser.getSegmentStandin(r, status));
    607                 } else {
    608                     pp.setIndex(pos);
    609                     UnicodeString name = parser.parseData->
    610                                     parseReference(rule, pp, limit);
    611                     if (name.length() == 0) {
    612                         // This means the '$' was not followed by a
    613                         // valid name.  Try to interpret it as an
    614                         // end anchor then.  If this also doesn't work
    615                         // (if we see a following character) then signal
    616                         // an error.
    617                         anchorEnd = TRUE;
    618                         break;
    619                     }
    620                     pos = pp.getIndex();
    621                     // If this is a variable definition statement,
    622                     // then the LHS variable will be undefined.  In
    623                     // that case appendVariableDef() will append the
    624                     // special placeholder char variableLimit-1.
    625                     varStart = buf.length();
    626                     parser.appendVariableDef(name, buf, status);
    627                     varLimit = buf.length();
    628                 }
    629             }
    630             break;
    631         case DOT:
    632             buf.append(parser.getDotStandIn(status));
    633             break;
    634         case KLEENE_STAR:
    635         case ONE_OR_MORE:
    636         case ZERO_OR_ONE:
    637             // Quantifiers.  We handle single characters, quoted strings,
    638             // variable references, and segments.
    639             //  a+      matches  aaa
    640             //  'foo'+  matches  foofoofoo
    641             //  $v+     matches  xyxyxy if $v == xy
    642             //  (seg)+  matches  segsegseg
    643             {
    644                 if (isSegment && buf.length() == bufStart) {
    645                     // The */+ immediately follows '('
    646                     return syntaxError(U_MISPLACED_QUANTIFIER, rule, start, status);
    647                 }
    648 
    649                 int32_t qstart, qlimit;
    650                 // The */+ follows an isolated character or quote
    651                 // or variable reference
    652                 if (buf.length() == quoteLimit) {
    653                     // The */+ follows a 'quoted string'
    654                     qstart = quoteStart;
    655                     qlimit = quoteLimit;
    656                 } else if (buf.length() == varLimit) {
    657                     // The */+ follows a $variableReference
    658                     qstart = varStart;
    659                     qlimit = varLimit;
    660                 } else {
    661                     // The */+ follows a single character, possibly
    662                     // a segment standin
    663                     qstart = buf.length() - 1;
    664                     qlimit = qstart + 1;
    665                 }
    666 
    667                 UnicodeFunctor *m =
    668                     new StringMatcher(buf, qstart, qlimit, 0, *parser.curData);
    669                 if (m == NULL) {
    670                     return syntaxError(U_MEMORY_ALLOCATION_ERROR, rule, start, status);
    671                 }
    672                 int32_t min = 0;
    673                 int32_t max = Quantifier::MAX;
    674                 switch (c) {
    675                 case ONE_OR_MORE:
    676                     min = 1;
    677                     break;
    678                 case ZERO_OR_ONE:
    679                     min = 0;
    680                     max = 1;
    681                     break;
    682                 // case KLEENE_STAR:
    683                 //    do nothing -- min, max already set
    684                 }
    685                 m = new Quantifier(m, min, max);
    686                 if (m == NULL) {
    687                     return syntaxError(U_MEMORY_ALLOCATION_ERROR, rule, start, status);
    688                 }
    689                 buf.truncate(qstart);
    690                 buf.append(parser.generateStandInFor(m, status));
    691             }
    692             break;
    693 
    694         //------------------------------------------------------
    695         // Elements allowed ONLY WITHIN segments
    696         //------------------------------------------------------
    697         case SEGMENT_CLOSE:
    698             // assert(isSegment);
    699             // We're done parsing a segment.
    700             done = TRUE;
    701             break;
    702 
    703         //------------------------------------------------------
    704         // Elements allowed ONLY OUTSIDE segments
    705         //------------------------------------------------------
    706         case CONTEXT_ANTE:
    707             if (ante >= 0) {
    708                 return syntaxError(U_MULTIPLE_ANTE_CONTEXTS, rule, start, status);
    709             }
    710             ante = buf.length();
    711             break;
    712         case CONTEXT_POST:
    713             if (post >= 0) {
    714                 return syntaxError(U_MULTIPLE_POST_CONTEXTS, rule, start, status);
    715             }
    716             post = buf.length();
    717             break;
    718         case CURSOR_POS:
    719             if (cursor >= 0) {
    720                 return syntaxError(U_MULTIPLE_CURSORS, rule, start, status);
    721             }
    722             cursor = buf.length();
    723             break;
    724         case CURSOR_OFFSET:
    725             if (cursorOffset < 0) {
    726                 if (buf.length() > 0) {
    727                     return syntaxError(U_MISPLACED_CURSOR_OFFSET, rule, start, status);
    728                 }
    729                 --cursorOffset;
    730             } else if (cursorOffset > 0) {
    731                 if (buf.length() != cursorOffsetPos || cursor >= 0) {
    732                     return syntaxError(U_MISPLACED_CURSOR_OFFSET, rule, start, status);
    733                 }
    734                 ++cursorOffset;
    735             } else {
    736                 if (cursor == 0 && buf.length() == 0) {
    737                     cursorOffset = -1;
    738                 } else if (cursor < 0) {
    739                     cursorOffsetPos = buf.length();
    740                     cursorOffset = 1;
    741                 } else {
    742                     return syntaxError(U_MISPLACED_CURSOR_OFFSET, rule, start, status);
    743                 }
    744             }
    745             break;
    746 
    747 
    748         //------------------------------------------------------
    749         // Non-special characters
    750         //------------------------------------------------------
    751         default:
    752             // Disallow unquoted characters other than [0-9A-Za-z]
    753             // in the printable ASCII range.  These characters are
    754             // reserved for possible future use.
    755             if (c >= 0x0021 && c <= 0x007E &&
    756                 !((c >= 0x0030/*'0'*/ && c <= 0x0039/*'9'*/) ||
    757                   (c >= 0x0041/*'A'*/ && c <= 0x005A/*'Z'*/) ||
    758                   (c >= 0x0061/*'a'*/ && c <= 0x007A/*'z'*/))) {
    759                 return syntaxError(U_UNQUOTED_SPECIAL, rule, start, status);
    760             }
    761             buf.append(c);
    762             break;
    763         }
    764     }
    765 
    766     return pos;
    767 }
    768 
    769 /**
    770  * Remove context.
    771  */
    772 void RuleHalf::removeContext() {
    773     //text = text.substring(ante < 0 ? 0 : ante,
    774     //                      post < 0 ? text.length() : post);
    775     if (post >= 0) {
    776         text.remove(post);
    777     }
    778     if (ante >= 0) {
    779         text.removeBetween(0, ante);
    780     }
    781     ante = post = -1;
    782     anchorStart = anchorEnd = FALSE;
    783 }
    784 
    785 /**
    786  * Return true if this half looks like valid output, that is, does not
    787  * contain quantifiers or other special input-only elements.
    788  */
    789 UBool RuleHalf::isValidOutput(TransliteratorParser& transParser) {
    790     for (int32_t i=0; i<text.length(); ) {
    791         UChar32 c = text.char32At(i);
    792         i += UTF_CHAR_LENGTH(c);
    793         if (!transParser.parseData->isReplacer(c)) {
    794             return FALSE;
    795         }
    796     }
    797     return TRUE;
    798 }
    799 
    800 /**
    801  * Return true if this half looks like valid input, that is, does not
    802  * contain functions or other special output-only elements.
    803  */
    804 UBool RuleHalf::isValidInput(TransliteratorParser& transParser) {
    805     for (int32_t i=0; i<text.length(); ) {
    806         UChar32 c = text.char32At(i);
    807         i += UTF_CHAR_LENGTH(c);
    808         if (!transParser.parseData->isMatcher(c)) {
    809             return FALSE;
    810         }
    811     }
    812     return TRUE;
    813 }
    814 
    815 //----------------------------------------------------------------------
    816 // PUBLIC API
    817 //----------------------------------------------------------------------
    818 
    819 /**
    820  * Constructor.
    821  */
    822 TransliteratorParser::TransliteratorParser(UErrorCode &statusReturn) :
    823 dataVector(statusReturn),
    824 idBlockVector(statusReturn),
    825 variablesVector(statusReturn),
    826 segmentObjects(statusReturn)
    827 {
    828     idBlockVector.setDeleter(uhash_deleteUnicodeString);
    829     curData = NULL;
    830     compoundFilter = NULL;
    831     parseData = NULL;
    832     variableNames.setValueDeleter(uhash_deleteUnicodeString);
    833 }
    834 
    835 /**
    836  * Destructor.
    837  */
    838 TransliteratorParser::~TransliteratorParser() {
    839     while (!dataVector.isEmpty())
    840         delete (TransliterationRuleData*)(dataVector.orphanElementAt(0));
    841     delete compoundFilter;
    842     delete parseData;
    843     while (!variablesVector.isEmpty())
    844         delete (UnicodeFunctor*)variablesVector.orphanElementAt(0);
    845 }
    846 
    847 void
    848 TransliteratorParser::parse(const UnicodeString& rules,
    849                             UTransDirection transDirection,
    850                             UParseError& pe,
    851                             UErrorCode& ec) {
    852     if (U_SUCCESS(ec)) {
    853         parseRules(rules, transDirection, ec);
    854         pe = parseError;
    855     }
    856 }
    857 
    858 /**
    859  * Return the compound filter parsed by parse().  Caller owns result.
    860  */
    861 UnicodeSet* TransliteratorParser::orphanCompoundFilter() {
    862     UnicodeSet* f = compoundFilter;
    863     compoundFilter = NULL;
    864     return f;
    865 }
    866 
    867 //----------------------------------------------------------------------
    868 // Private implementation
    869 //----------------------------------------------------------------------
    870 
    871 /**
    872  * Parse the given string as a sequence of rules, separated by newline
    873  * characters ('\n'), and cause this object to implement those rules.  Any
    874  * previous rules are discarded.  Typically this method is called exactly
    875  * once, during construction.
    876  * @exception IllegalArgumentException if there is a syntax error in the
    877  * rules
    878  */
    879 void TransliteratorParser::parseRules(const UnicodeString& rule,
    880                                       UTransDirection theDirection,
    881                                       UErrorCode& status)
    882 {
    883     // Clear error struct
    884     uprv_memset(&parseError, 0, sizeof(parseError));
    885     parseError.line = parseError.offset = -1;
    886 
    887     UBool parsingIDs = TRUE;
    888     int32_t ruleCount = 0;
    889 
    890     while (!dataVector.isEmpty()) {
    891         delete (TransliterationRuleData*)(dataVector.orphanElementAt(0));
    892     }
    893     if (U_FAILURE(status)) {
    894         return;
    895     }
    896 
    897     idBlockVector.removeAllElements();
    898     curData = NULL;
    899     direction = theDirection;
    900     ruleCount = 0;
    901 
    902     delete compoundFilter;
    903     compoundFilter = NULL;
    904 
    905     while (!variablesVector.isEmpty()) {
    906         delete (UnicodeFunctor*)variablesVector.orphanElementAt(0);
    907     }
    908     variableNames.removeAll();
    909     parseData = new ParseData(0, &variablesVector, &variableNames);
    910     if (parseData == NULL) {
    911         status = U_MEMORY_ALLOCATION_ERROR;
    912         return;
    913     }
    914 
    915     dotStandIn = (UChar) -1;
    916 
    917     UnicodeString *tempstr = NULL; // used for memory allocation error checking
    918     UnicodeString str; // scratch
    919     UnicodeString idBlockResult;
    920     int32_t pos = 0;
    921     int32_t limit = rule.length();
    922 
    923     // The compound filter offset is an index into idBlockResult.
    924     // If it is 0, then the compound filter occurred at the start,
    925     // and it is the offset to the _start_ of the compound filter
    926     // pattern.  Otherwise it is the offset to the _limit_ of the
    927     // compound filter pattern within idBlockResult.
    928     compoundFilter = NULL;
    929     int32_t compoundFilterOffset = -1;
    930 
    931     while (pos < limit && U_SUCCESS(status)) {
    932         UChar c = rule.charAt(pos++);
    933         if (PatternProps::isWhiteSpace(c)) {
    934             // Ignore leading whitespace.
    935             continue;
    936         }
    937         // Skip lines starting with the comment character
    938         if (c == RULE_COMMENT_CHAR) {
    939             pos = rule.indexOf((UChar)0x000A /*\n*/, pos) + 1;
    940             if (pos == 0) {
    941                 break; // No "\n" found; rest of rule is a commnet
    942             }
    943             continue; // Either fall out or restart with next line
    944         }
    945 
    946         // skip empty rules
    947         if (c == END_OF_RULE)
    948             continue;
    949 
    950         // keep track of how many rules we've seen
    951         ++ruleCount;
    952 
    953         // We've found the start of a rule or ID.  c is its first
    954         // character, and pos points past c.
    955         --pos;
    956         // Look for an ID token.  Must have at least ID_TOKEN_LEN + 1
    957         // chars left.
    958         if ((pos + ID_TOKEN_LEN + 1) <= limit &&
    959                 rule.compare(pos, ID_TOKEN_LEN, ID_TOKEN) == 0) {
    960             pos += ID_TOKEN_LEN;
    961             c = rule.charAt(pos);
    962             while (PatternProps::isWhiteSpace(c) && pos < limit) {
    963                 ++pos;
    964                 c = rule.charAt(pos);
    965             }
    966 
    967             int32_t p = pos;
    968 
    969             if (!parsingIDs) {
    970                 if (curData != NULL) {
    971                     if (direction == UTRANS_FORWARD)
    972                         dataVector.addElement(curData, status);
    973                     else
    974                         dataVector.insertElementAt(curData, 0, status);
    975                     curData = NULL;
    976                 }
    977                 parsingIDs = TRUE;
    978             }
    979 
    980             TransliteratorIDParser::SingleID* id =
    981                 TransliteratorIDParser::parseSingleID(rule, p, direction, status);
    982             if (p != pos && ICU_Utility::parseChar(rule, p, END_OF_RULE)) {
    983                 // Successful ::ID parse.
    984 
    985                 if (direction == UTRANS_FORWARD) {
    986                     idBlockResult.append(id->canonID).append(END_OF_RULE);
    987                 } else {
    988                     idBlockResult.insert(0, END_OF_RULE);
    989                     idBlockResult.insert(0, id->canonID);
    990                 }
    991 
    992             } else {
    993                 // Couldn't parse an ID.  Try to parse a global filter
    994                 int32_t withParens = -1;
    995                 UnicodeSet* f = TransliteratorIDParser::parseGlobalFilter(rule, p, direction, withParens, NULL);
    996                 if (f != NULL) {
    997                     if (ICU_Utility::parseChar(rule, p, END_OF_RULE)
    998                         && (direction == UTRANS_FORWARD) == (withParens == 0))
    999                     {
   1000                         if (compoundFilter != NULL) {
   1001                             // Multiple compound filters
   1002                             syntaxError(U_MULTIPLE_COMPOUND_FILTERS, rule, pos, status);
   1003                             delete f;
   1004                         } else {
   1005                             compoundFilter = f;
   1006                             compoundFilterOffset = ruleCount;
   1007                         }
   1008                     } else {
   1009                         delete f;
   1010                     }
   1011                 } else {
   1012                     // Invalid ::id
   1013                     // Can be parsed as neither an ID nor a global filter
   1014                     syntaxError(U_INVALID_ID, rule, pos, status);
   1015                 }
   1016             }
   1017             delete id;
   1018             pos = p;
   1019         } else {
   1020             if (parsingIDs) {
   1021                 tempstr = new UnicodeString(idBlockResult);
   1022                 // NULL pointer check
   1023                 if (tempstr == NULL) {
   1024                     status = U_MEMORY_ALLOCATION_ERROR;
   1025                     return;
   1026                 }
   1027                 if (direction == UTRANS_FORWARD)
   1028                     idBlockVector.addElement(tempstr, status);
   1029                 else
   1030                     idBlockVector.insertElementAt(tempstr, 0, status);
   1031                 idBlockResult.remove();
   1032                 parsingIDs = FALSE;
   1033                 curData = new TransliterationRuleData(status);
   1034                 // NULL pointer check
   1035                 if (curData == NULL) {
   1036                     status = U_MEMORY_ALLOCATION_ERROR;
   1037                     return;
   1038                 }
   1039                 parseData->data = curData;
   1040 
   1041                 // By default, rules use part of the private use area
   1042                 // E000..F8FF for variables and other stand-ins.  Currently
   1043                 // the range F000..F8FF is typically sufficient.  The 'use
   1044                 // variable range' pragma allows rule sets to modify this.
   1045                 setVariableRange(0xF000, 0xF8FF, status);
   1046             }
   1047 
   1048             if (resemblesPragma(rule, pos, limit)) {
   1049                 int32_t ppp = parsePragma(rule, pos, limit, status);
   1050                 if (ppp < 0) {
   1051                     syntaxError(U_MALFORMED_PRAGMA, rule, pos, status);
   1052                 }
   1053                 pos = ppp;
   1054             // Parse a rule
   1055             } else {
   1056                 pos = parseRule(rule, pos, limit, status);
   1057             }
   1058         }
   1059     }
   1060 
   1061     if (parsingIDs && idBlockResult.length() > 0) {
   1062         tempstr = new UnicodeString(idBlockResult);
   1063         // NULL pointer check
   1064         if (tempstr == NULL) {
   1065             status = U_MEMORY_ALLOCATION_ERROR;
   1066             return;
   1067         }
   1068         if (direction == UTRANS_FORWARD)
   1069             idBlockVector.addElement(tempstr, status);
   1070         else
   1071             idBlockVector.insertElementAt(tempstr, 0, status);
   1072     }
   1073     else if (!parsingIDs && curData != NULL) {
   1074         if (direction == UTRANS_FORWARD)
   1075             dataVector.addElement(curData, status);
   1076         else
   1077             dataVector.insertElementAt(curData, 0, status);
   1078     }
   1079 
   1080     if (U_SUCCESS(status)) {
   1081         // Convert the set vector to an array
   1082         int32_t i, dataVectorSize = dataVector.size();
   1083         for (i = 0; i < dataVectorSize; i++) {
   1084             TransliterationRuleData* data = (TransliterationRuleData*)dataVector.elementAt(i);
   1085             data->variablesLength = variablesVector.size();
   1086             if (data->variablesLength == 0) {
   1087                 data->variables = 0;
   1088             } else {
   1089                 data->variables = (UnicodeFunctor**)uprv_malloc(data->variablesLength * sizeof(UnicodeFunctor*));
   1090                 // NULL pointer check
   1091                 if (data->variables == NULL) {
   1092                     status = U_MEMORY_ALLOCATION_ERROR;
   1093                     return;
   1094                 }
   1095                 data->variablesAreOwned = (i == 0);
   1096             }
   1097 
   1098             for (int32_t j = 0; j < data->variablesLength; j++) {
   1099                 data->variables[j] =
   1100                     ((UnicodeSet*)variablesVector.elementAt(j));
   1101             }
   1102 
   1103             data->variableNames.removeAll();
   1104             int32_t pos = -1;
   1105             const UHashElement* he = variableNames.nextElement(pos);
   1106             while (he != NULL) {
   1107                 UnicodeString* tempus = (UnicodeString*)(((UnicodeString*)(he->value.pointer))->clone());
   1108                 if (tempus == NULL) {
   1109                     status = U_MEMORY_ALLOCATION_ERROR;
   1110                     return;
   1111                 }
   1112                 data->variableNames.put(*((UnicodeString*)(he->key.pointer)),
   1113                     tempus, status);
   1114                 he = variableNames.nextElement(pos);
   1115             }
   1116         }
   1117         variablesVector.removeAllElements();   // keeps them from getting deleted when we succeed
   1118 
   1119         // Index the rules
   1120         if (compoundFilter != NULL) {
   1121             if ((direction == UTRANS_FORWARD && compoundFilterOffset != 1) ||
   1122                 (direction == UTRANS_REVERSE && compoundFilterOffset != ruleCount)) {
   1123                 status = U_MISPLACED_COMPOUND_FILTER;
   1124             }
   1125         }
   1126 
   1127         for (i = 0; i < dataVectorSize; i++) {
   1128             TransliterationRuleData* data = (TransliterationRuleData*)dataVector.elementAt(i);
   1129             data->ruleSet.freeze(parseError, status);
   1130         }
   1131         if (idBlockVector.size() == 1 && ((UnicodeString*)idBlockVector.elementAt(0))->isEmpty()) {
   1132             idBlockVector.removeElementAt(0);
   1133         }
   1134     }
   1135 }
   1136 
   1137 /**
   1138  * Set the variable range to [start, end] (inclusive).
   1139  */
   1140 void TransliteratorParser::setVariableRange(int32_t start, int32_t end, UErrorCode& status) {
   1141     if (start > end || start < 0 || end > 0xFFFF) {
   1142         status = U_MALFORMED_PRAGMA;
   1143         return;
   1144     }
   1145 
   1146     curData->variablesBase = (UChar) start;
   1147     if (dataVector.size() == 0) {
   1148         variableNext = (UChar) start;
   1149         variableLimit = (UChar) (end + 1);
   1150     }
   1151 }
   1152 
   1153 /**
   1154  * Assert that the given character is NOT within the variable range.
   1155  * If it is, return FALSE.  This is neccesary to ensure that the
   1156  * variable range does not overlap characters used in a rule.
   1157  */
   1158 UBool TransliteratorParser::checkVariableRange(UChar32 ch) const {
   1159     return !(ch >= curData->variablesBase && ch < variableLimit);
   1160 }
   1161 
   1162 /**
   1163  * Set the maximum backup to 'backup', in response to a pragma
   1164  * statement.
   1165  */
   1166 void TransliteratorParser::pragmaMaximumBackup(int32_t /*backup*/) {
   1167     //TODO Finish
   1168 }
   1169 
   1170 /**
   1171  * Begin normalizing all rules using the given mode, in response
   1172  * to a pragma statement.
   1173  */
   1174 void TransliteratorParser::pragmaNormalizeRules(UNormalizationMode /*mode*/) {
   1175     //TODO Finish
   1176 }
   1177 
   1178 static const UChar PRAGMA_USE[] = {0x75,0x73,0x65,0x20,0}; // "use "
   1179 
   1180 static const UChar PRAGMA_VARIABLE_RANGE[] = {0x7E,0x76,0x61,0x72,0x69,0x61,0x62,0x6C,0x65,0x20,0x72,0x61,0x6E,0x67,0x65,0x20,0x23,0x20,0x23,0x7E,0x3B,0}; // "~variable range # #~;"
   1181 
   1182 static const UChar PRAGMA_MAXIMUM_BACKUP[] = {0x7E,0x6D,0x61,0x78,0x69,0x6D,0x75,0x6D,0x20,0x62,0x61,0x63,0x6B,0x75,0x70,0x20,0x23,0x7E,0x3B,0}; // "~maximum backup #~;"
   1183 
   1184 static const UChar PRAGMA_NFD_RULES[] = {0x7E,0x6E,0x66,0x64,0x20,0x72,0x75,0x6C,0x65,0x73,0x7E,0x3B,0}; // "~nfd rules~;"
   1185 
   1186 static const UChar PRAGMA_NFC_RULES[] = {0x7E,0x6E,0x66,0x63,0x20,0x72,0x75,0x6C,0x65,0x73,0x7E,0x3B,0}; // "~nfc rules~;"
   1187 
   1188 /**
   1189  * Return true if the given rule looks like a pragma.
   1190  * @param pos offset to the first non-whitespace character
   1191  * of the rule.
   1192  * @param limit pointer past the last character of the rule.
   1193  */
   1194 UBool TransliteratorParser::resemblesPragma(const UnicodeString& rule, int32_t pos, int32_t limit) {
   1195     // Must start with /use\s/i
   1196     return ICU_Utility::parsePattern(rule, pos, limit, PRAGMA_USE, NULL) >= 0;
   1197 }
   1198 
   1199 /**
   1200  * Parse a pragma.  This method assumes resemblesPragma() has
   1201  * already returned true.
   1202  * @param pos offset to the first non-whitespace character
   1203  * of the rule.
   1204  * @param limit pointer past the last character of the rule.
   1205  * @return the position index after the final ';' of the pragma,
   1206  * or -1 on failure.
   1207  */
   1208 int32_t TransliteratorParser::parsePragma(const UnicodeString& rule, int32_t pos, int32_t limit, UErrorCode& status) {
   1209     int32_t array[2];
   1210 
   1211     // resemblesPragma() has already returned true, so we
   1212     // know that pos points to /use\s/i; we can skip 4 characters
   1213     // immediately
   1214     pos += 4;
   1215 
   1216     // Here are the pragmas we recognize:
   1217     // use variable range 0xE000 0xEFFF;
   1218     // use maximum backup 16;
   1219     // use nfd rules;
   1220     // use nfc rules;
   1221     int p = ICU_Utility::parsePattern(rule, pos, limit, PRAGMA_VARIABLE_RANGE, array);
   1222     if (p >= 0) {
   1223         setVariableRange(array[0], array[1], status);
   1224         return p;
   1225     }
   1226 
   1227     p = ICU_Utility::parsePattern(rule, pos, limit, PRAGMA_MAXIMUM_BACKUP, array);
   1228     if (p >= 0) {
   1229         pragmaMaximumBackup(array[0]);
   1230         return p;
   1231     }
   1232 
   1233     p = ICU_Utility::parsePattern(rule, pos, limit, PRAGMA_NFD_RULES, NULL);
   1234     if (p >= 0) {
   1235         pragmaNormalizeRules(UNORM_NFD);
   1236         return p;
   1237     }
   1238 
   1239     p = ICU_Utility::parsePattern(rule, pos, limit, PRAGMA_NFC_RULES, NULL);
   1240     if (p >= 0) {
   1241         pragmaNormalizeRules(UNORM_NFC);
   1242         return p;
   1243     }
   1244 
   1245     // Syntax error: unable to parse pragma
   1246     return -1;
   1247 }
   1248 
   1249 /**
   1250  * MAIN PARSER.  Parse the next rule in the given rule string, starting
   1251  * at pos.  Return the index after the last character parsed.  Do not
   1252  * parse characters at or after limit.
   1253  *
   1254  * Important:  The character at pos must be a non-whitespace character
   1255  * that is not the comment character.
   1256  *
   1257  * This method handles quoting, escaping, and whitespace removal.  It
   1258  * parses the end-of-rule character.  It recognizes context and cursor
   1259  * indicators.  Once it does a lexical breakdown of the rule at pos, it
   1260  * creates a rule object and adds it to our rule list.
   1261  */
   1262 int32_t TransliteratorParser::parseRule(const UnicodeString& rule, int32_t pos, int32_t limit, UErrorCode& status) {
   1263     // Locate the left side, operator, and right side
   1264     int32_t start = pos;
   1265     UChar op = 0;
   1266     int32_t i;
   1267 
   1268     // Set up segments data
   1269     segmentStandins.truncate(0);
   1270     segmentObjects.removeAllElements();
   1271 
   1272     // Use pointers to automatics to make swapping possible.
   1273     RuleHalf _left(*this), _right(*this);
   1274     RuleHalf* left = &_left;
   1275     RuleHalf* right = &_right;
   1276 
   1277     undefinedVariableName.remove();
   1278     pos = left->parse(rule, pos, limit, status);
   1279     if (U_FAILURE(status)) {
   1280         return start;
   1281     }
   1282 
   1283     if (pos == limit || u_strchr(gOPERATORS, (op = rule.charAt(--pos))) == NULL) {
   1284         return syntaxError(U_MISSING_OPERATOR, rule, start, status);
   1285     }
   1286     ++pos;
   1287 
   1288     // Found an operator char.  Check for forward-reverse operator.
   1289     if (op == REVERSE_RULE_OP &&
   1290         (pos < limit && rule.charAt(pos) == FORWARD_RULE_OP)) {
   1291         ++pos;
   1292         op = FWDREV_RULE_OP;
   1293     }
   1294 
   1295     // Translate alternate op characters.
   1296     switch (op) {
   1297     case ALT_FORWARD_RULE_OP:
   1298         op = FORWARD_RULE_OP;
   1299         break;
   1300     case ALT_REVERSE_RULE_OP:
   1301         op = REVERSE_RULE_OP;
   1302         break;
   1303     case ALT_FWDREV_RULE_OP:
   1304         op = FWDREV_RULE_OP;
   1305         break;
   1306     }
   1307 
   1308     pos = right->parse(rule, pos, limit, status);
   1309     if (U_FAILURE(status)) {
   1310         return start;
   1311     }
   1312 
   1313     if (pos < limit) {
   1314         if (rule.charAt(--pos) == END_OF_RULE) {
   1315             ++pos;
   1316         } else {
   1317             // RuleHalf parser must have terminated at an operator
   1318             return syntaxError(U_UNQUOTED_SPECIAL, rule, start, status);
   1319         }
   1320     }
   1321 
   1322     if (op == VARIABLE_DEF_OP) {
   1323         // LHS is the name.  RHS is a single character, either a literal
   1324         // or a set (already parsed).  If RHS is longer than one
   1325         // character, it is either a multi-character string, or multiple
   1326         // sets, or a mixture of chars and sets -- syntax error.
   1327 
   1328         // We expect to see a single undefined variable (the one being
   1329         // defined).
   1330         if (undefinedVariableName.length() == 0) {
   1331             // "Missing '$' or duplicate definition"
   1332             return syntaxError(U_BAD_VARIABLE_DEFINITION, rule, start, status);
   1333         }
   1334         if (left->text.length() != 1 || left->text.charAt(0) != variableLimit) {
   1335             // "Malformed LHS"
   1336             return syntaxError(U_MALFORMED_VARIABLE_DEFINITION, rule, start, status);
   1337         }
   1338         if (left->anchorStart || left->anchorEnd ||
   1339             right->anchorStart || right->anchorEnd) {
   1340             return syntaxError(U_MALFORMED_VARIABLE_DEFINITION, rule, start, status);
   1341         }
   1342         // We allow anything on the right, including an empty string.
   1343         UnicodeString* value = new UnicodeString(right->text);
   1344         // NULL pointer check
   1345         if (value == NULL) {
   1346             return syntaxError(U_MEMORY_ALLOCATION_ERROR, rule, start, status);
   1347         }
   1348         variableNames.put(undefinedVariableName, value, status);
   1349         ++variableLimit;
   1350         return pos;
   1351     }
   1352 
   1353     // If this is not a variable definition rule, we shouldn't have
   1354     // any undefined variable names.
   1355     if (undefinedVariableName.length() != 0) {
   1356         return syntaxError(// "Undefined variable $" + undefinedVariableName,
   1357                     U_UNDEFINED_VARIABLE,
   1358                     rule, start, status);
   1359     }
   1360 
   1361     // Verify segments
   1362     if (segmentStandins.length() > segmentObjects.size()) {
   1363         syntaxError(U_UNDEFINED_SEGMENT_REFERENCE, rule, start, status);
   1364     }
   1365     for (i=0; i<segmentStandins.length(); ++i) {
   1366         if (segmentStandins.charAt(i) == 0) {
   1367             syntaxError(U_INTERNAL_TRANSLITERATOR_ERROR, rule, start, status); // will never happen
   1368         }
   1369     }
   1370     for (i=0; i<segmentObjects.size(); ++i) {
   1371         if (segmentObjects.elementAt(i) == NULL) {
   1372             syntaxError(U_INTERNAL_TRANSLITERATOR_ERROR, rule, start, status); // will never happen
   1373         }
   1374     }
   1375 
   1376     // If the direction we want doesn't match the rule
   1377     // direction, do nothing.
   1378     if (op != FWDREV_RULE_OP &&
   1379         ((direction == UTRANS_FORWARD) != (op == FORWARD_RULE_OP))) {
   1380         return pos;
   1381     }
   1382 
   1383     // Transform the rule into a forward rule by swapping the
   1384     // sides if necessary.
   1385     if (direction == UTRANS_REVERSE) {
   1386         left = &_right;
   1387         right = &_left;
   1388     }
   1389 
   1390     // Remove non-applicable elements in forward-reverse
   1391     // rules.  Bidirectional rules ignore elements that do not
   1392     // apply.
   1393     if (op == FWDREV_RULE_OP) {
   1394         right->removeContext();
   1395         left->cursor = -1;
   1396         left->cursorOffset = 0;
   1397     }
   1398 
   1399     // Normalize context
   1400     if (left->ante < 0) {
   1401         left->ante = 0;
   1402     }
   1403     if (left->post < 0) {
   1404         left->post = left->text.length();
   1405     }
   1406 
   1407     // Context is only allowed on the input side.  Cursors are only
   1408     // allowed on the output side.  Segment delimiters can only appear
   1409     // on the left, and references on the right.  Cursor offset
   1410     // cannot appear without an explicit cursor.  Cursor offset
   1411     // cannot place the cursor outside the limits of the context.
   1412     // Anchors are only allowed on the input side.
   1413     if (right->ante >= 0 || right->post >= 0 || left->cursor >= 0 ||
   1414         (right->cursorOffset != 0 && right->cursor < 0) ||
   1415         // - The following two checks were used to ensure that the
   1416         // - the cursor offset stayed within the ante- or postcontext.
   1417         // - However, with the addition of quantifiers, we have to
   1418         // - allow arbitrary cursor offsets and do runtime checking.
   1419         //(right->cursorOffset > (left->text.length() - left->post)) ||
   1420         //(-right->cursorOffset > left->ante) ||
   1421         right->anchorStart || right->anchorEnd ||
   1422         !left->isValidInput(*this) || !right->isValidOutput(*this) ||
   1423         left->ante > left->post) {
   1424 
   1425         return syntaxError(U_MALFORMED_RULE, rule, start, status);
   1426     }
   1427 
   1428     // Flatten segment objects vector to an array
   1429     UnicodeFunctor** segmentsArray = NULL;
   1430     if (segmentObjects.size() > 0) {
   1431         segmentsArray = (UnicodeFunctor **)uprv_malloc(segmentObjects.size() * sizeof(UnicodeFunctor *));
   1432         // Null pointer check
   1433         if (segmentsArray == NULL) {
   1434             return syntaxError(U_MEMORY_ALLOCATION_ERROR, rule, start, status);
   1435         }
   1436         segmentObjects.toArray((void**) segmentsArray);
   1437     }
   1438     TransliterationRule* temptr = new TransliterationRule(
   1439             left->text, left->ante, left->post,
   1440             right->text, right->cursor, right->cursorOffset,
   1441             segmentsArray,
   1442             segmentObjects.size(),
   1443             left->anchorStart, left->anchorEnd,
   1444             curData,
   1445             status);
   1446     //Null pointer check
   1447     if (temptr == NULL) {
   1448         uprv_free(segmentsArray);
   1449         return syntaxError(U_MEMORY_ALLOCATION_ERROR, rule, start, status);
   1450     }
   1451 
   1452     curData->ruleSet.addRule(temptr, status);
   1453 
   1454     return pos;
   1455 }
   1456 
   1457 /**
   1458  * Called by main parser upon syntax error.  Search the rule string
   1459  * for the probable end of the rule.  Of course, if the error is that
   1460  * the end of rule marker is missing, then the rule end will not be found.
   1461  * In any case the rule start will be correctly reported.
   1462  * @param msg error description
   1463  * @param rule pattern string
   1464  * @param start position of first character of current rule
   1465  */
   1466 int32_t TransliteratorParser::syntaxError(UErrorCode parseErrorCode,
   1467                                           const UnicodeString& rule,
   1468                                           int32_t pos,
   1469                                           UErrorCode& status)
   1470 {
   1471     parseError.offset = pos;
   1472     parseError.line = 0 ; /* we are not using line numbers */
   1473 
   1474     // for pre-context
   1475     const int32_t LEN = U_PARSE_CONTEXT_LEN - 1;
   1476     int32_t start = uprv_max(pos - LEN, 0);
   1477     int32_t stop  = pos;
   1478 
   1479     rule.extract(start,stop-start,parseError.preContext);
   1480     //null terminate the buffer
   1481     parseError.preContext[stop-start] = 0;
   1482 
   1483     //for post-context
   1484     start = pos;
   1485     stop  = uprv_min(pos + LEN, rule.length());
   1486 
   1487     rule.extract(start,stop-start,parseError.postContext);
   1488     //null terminate the buffer
   1489     parseError.postContext[stop-start]= 0;
   1490 
   1491     status = (UErrorCode)parseErrorCode;
   1492     return pos;
   1493 
   1494 }
   1495 
   1496 /**
   1497  * Parse a UnicodeSet out, store it, and return the stand-in character
   1498  * used to represent it.
   1499  */
   1500 UChar TransliteratorParser::parseSet(const UnicodeString& rule,
   1501                                           ParsePosition& pos,
   1502                                           UErrorCode& status) {
   1503     UnicodeSet* set = new UnicodeSet(rule, pos, USET_IGNORE_SPACE, parseData, status);
   1504     // Null pointer check
   1505     if (set == NULL) {
   1506         status = U_MEMORY_ALLOCATION_ERROR;
   1507         return (UChar)0x0000; // Return empty character with error.
   1508     }
   1509     set->compact();
   1510     return generateStandInFor(set, status);
   1511 }
   1512 
   1513 /**
   1514  * Generate and return a stand-in for a new UnicodeFunctor.  Store
   1515  * the matcher (adopt it).
   1516  */
   1517 UChar TransliteratorParser::generateStandInFor(UnicodeFunctor* adopted, UErrorCode& status) {
   1518     // assert(obj != null);
   1519 
   1520     // Look up previous stand-in, if any.  This is a short list
   1521     // (typical n is 0, 1, or 2); linear search is optimal.
   1522     for (int32_t i=0; i<variablesVector.size(); ++i) {
   1523         if (variablesVector.elementAt(i) == adopted) { // [sic] pointer comparison
   1524             return (UChar) (curData->variablesBase + i);
   1525         }
   1526     }
   1527 
   1528     if (variableNext >= variableLimit) {
   1529         delete adopted;
   1530         status = U_VARIABLE_RANGE_EXHAUSTED;
   1531         return 0;
   1532     }
   1533     variablesVector.addElement(adopted, status);
   1534     return variableNext++;
   1535 }
   1536 
   1537 /**
   1538  * Return the standin for segment seg (1-based).
   1539  */
   1540 UChar TransliteratorParser::getSegmentStandin(int32_t seg, UErrorCode& status) {
   1541     // Special character used to indicate an empty spot
   1542     UChar empty = curData->variablesBase - 1;
   1543     while (segmentStandins.length() < seg) {
   1544         segmentStandins.append(empty);
   1545     }
   1546     UChar c = segmentStandins.charAt(seg-1);
   1547     if (c == empty) {
   1548         if (variableNext >= variableLimit) {
   1549             status = U_VARIABLE_RANGE_EXHAUSTED;
   1550             return 0;
   1551         }
   1552         c = variableNext++;
   1553         // Set a placeholder in the master variables vector that will be
   1554         // filled in later by setSegmentObject().  We know that we will get
   1555         // called first because setSegmentObject() will call us.
   1556         variablesVector.addElement((void*) NULL, status);
   1557         segmentStandins.setCharAt(seg-1, c);
   1558     }
   1559     return c;
   1560 }
   1561 
   1562 /**
   1563  * Set the object for segment seg (1-based).
   1564  */
   1565 void TransliteratorParser::setSegmentObject(int32_t seg, StringMatcher* adopted, UErrorCode& status) {
   1566     // Since we call parseSection() recursively, nested
   1567     // segments will result in segment i+1 getting parsed
   1568     // and stored before segment i; be careful with the
   1569     // vector handling here.
   1570     if (segmentObjects.size() < seg) {
   1571         segmentObjects.setSize(seg, status);
   1572     }
   1573     int32_t index = getSegmentStandin(seg, status) - curData->variablesBase;
   1574     if (segmentObjects.elementAt(seg-1) != NULL ||
   1575         variablesVector.elementAt(index) != NULL) {
   1576         // should never happen
   1577         status = U_INTERNAL_TRANSLITERATOR_ERROR;
   1578         return;
   1579     }
   1580     segmentObjects.setElementAt(adopted, seg-1);
   1581     variablesVector.setElementAt(adopted, index);
   1582 }
   1583 
   1584 /**
   1585  * Return the stand-in for the dot set.  It is allocated the first
   1586  * time and reused thereafter.
   1587  */
   1588 UChar TransliteratorParser::getDotStandIn(UErrorCode& status) {
   1589     if (dotStandIn == (UChar) -1) {
   1590         UnicodeSet* tempus = new UnicodeSet(DOT_SET, status);
   1591         // Null pointer check.
   1592         if (tempus == NULL) {
   1593             status = U_MEMORY_ALLOCATION_ERROR;
   1594             return (UChar)0x0000;
   1595         }
   1596         dotStandIn = generateStandInFor(tempus, status);
   1597     }
   1598     return dotStandIn;
   1599 }
   1600 
   1601 /**
   1602  * Append the value of the given variable name to the given
   1603  * UnicodeString.
   1604  */
   1605 void TransliteratorParser::appendVariableDef(const UnicodeString& name,
   1606                                                   UnicodeString& buf,
   1607                                                   UErrorCode& status) {
   1608     const UnicodeString* s = (const UnicodeString*) variableNames.get(name);
   1609     if (s == NULL) {
   1610         // We allow one undefined variable so that variable definition
   1611         // statements work.  For the first undefined variable we return
   1612         // the special placeholder variableLimit-1, and save the variable
   1613         // name.
   1614         if (undefinedVariableName.length() == 0) {
   1615             undefinedVariableName = name;
   1616             if (variableNext >= variableLimit) {
   1617                 // throw new RuntimeException("Private use variables exhausted");
   1618                 status = U_ILLEGAL_ARGUMENT_ERROR;
   1619                 return;
   1620             }
   1621             buf.append((UChar) --variableLimit);
   1622         } else {
   1623             //throw new IllegalArgumentException("Undefined variable $"
   1624             //                                   + name);
   1625             status = U_ILLEGAL_ARGUMENT_ERROR;
   1626             return;
   1627         }
   1628     } else {
   1629         buf.append(*s);
   1630     }
   1631 }
   1632 
   1633 /**
   1634  * Glue method to get around access restrictions in C++.
   1635  */
   1636 /*Transliterator* TransliteratorParser::createBasicInstance(const UnicodeString& id, const UnicodeString* canonID) {
   1637     return Transliterator::createBasicInstance(id, canonID);
   1638 }*/
   1639 
   1640 U_NAMESPACE_END
   1641 
   1642 U_CAPI int32_t
   1643 utrans_stripRules(const UChar *source, int32_t sourceLen, UChar *target, UErrorCode *status) {
   1644     U_NAMESPACE_USE
   1645 
   1646     //const UChar *sourceStart = source;
   1647     const UChar *targetStart = target;
   1648     const UChar *sourceLimit = source+sourceLen;
   1649     UChar *targetLimit = target+sourceLen;
   1650     UChar32 c = 0;
   1651     UBool quoted = FALSE;
   1652     int32_t index;
   1653 
   1654     uprv_memset(target, 0, sourceLen*U_SIZEOF_UCHAR);
   1655 
   1656     /* read the rules into the buffer */
   1657     while (source < sourceLimit)
   1658     {
   1659         index=0;
   1660         U16_NEXT_UNSAFE(source, index, c);
   1661         source+=index;
   1662         if(c == QUOTE) {
   1663             quoted = (UBool)!quoted;
   1664         }
   1665         else if (!quoted) {
   1666             if (c == RULE_COMMENT_CHAR) {
   1667                 /* skip comments and all preceding spaces */
   1668                 while (targetStart < target && *(target - 1) == 0x0020) {
   1669                     target--;
   1670                 }
   1671                 do {
   1672                     c = *(source++);
   1673                 }
   1674                 while (c != CR && c != LF);
   1675             }
   1676             else if (c == ESCAPE) {
   1677                 UChar32   c2 = *source;
   1678                 if (c2 == CR || c2 == LF) {
   1679                     /* A backslash at the end of a line. */
   1680                     /* Since we're stripping lines, ignore the backslash. */
   1681                     source++;
   1682                     continue;
   1683                 }
   1684                 if (c2 == 0x0075 && source+5 < sourceLimit) { /* \u seen. \U isn't unescaped. */
   1685                     int32_t escapeOffset = 0;
   1686                     UnicodeString escapedStr(source, 5);
   1687                     c2 = escapedStr.unescapeAt(escapeOffset);
   1688 
   1689                     if (c2 == (UChar32)0xFFFFFFFF || escapeOffset == 0)
   1690                     {
   1691                         *status = U_PARSE_ERROR;
   1692                         return 0;
   1693                     }
   1694                     if (!PatternProps::isWhiteSpace(c2) && !u_iscntrl(c2) && !u_ispunct(c2)) {
   1695                         /* It was escaped for a reason. Write what it was suppose to be. */
   1696                         source+=5;
   1697                         c = c2;
   1698                     }
   1699                 }
   1700                 else if (c2 == QUOTE) {
   1701                     /* \' seen. Make sure we don't do anything when we see it again. */
   1702                     quoted = (UBool)!quoted;
   1703                 }
   1704             }
   1705         }
   1706         if (c == CR || c == LF)
   1707         {
   1708             /* ignore spaces carriage returns, and all leading spaces on the next line.
   1709             * and line feed unless in the form \uXXXX
   1710             */
   1711             quoted = FALSE;
   1712             while (source < sourceLimit) {
   1713                 c = *(source);
   1714                 if (c != CR && c != LF && c != 0x0020) {
   1715                     break;
   1716                 }
   1717                 source++;
   1718             }
   1719             continue;
   1720         }
   1721 
   1722         /* Append UChar * after dissembling if c > 0xffff*/
   1723         index=0;
   1724         U16_APPEND_UNSAFE(target, index, c);
   1725         target+=index;
   1726     }
   1727     if (target < targetLimit) {
   1728         *target = 0;
   1729     }
   1730     return (int32_t)(target-targetStart);
   1731 }
   1732 
   1733 #endif /* #if !UCONFIG_NO_TRANSLITERATION */
   1734