The Tor Browser: intl/icu/source/i18n/regexcmp.cpp@fc2d59ddac77 (annotated)

intl/icu/source/i18n/regexcmp.cpp@fc2d59ddac77 (annotated)

intl/icu/source/i18n/regexcmp.cpp

Wed, 31 Dec 2014 07:22:50 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 07:22:50 +0100
branch: TOR_BUG_3246
changeset 4: fc2d59ddac77
permissions: -rw-r--r--

Correct previous dual key logic pending first delivery installment.

 //
 //  file:  regexcmp.cpp
 //
 //  Copyright (C) 2002-2013 International Business Machines Corporation and others.
 //  All Rights Reserved.
 //
 //  This file contains the ICU regular expression compiler, which is responsible
 //  for processing a regular expression pattern into the compiled form that
 //  is used by the match finding engine.
 //
 #include "unicode/utypes.h"
 #if !UCONFIG_NO_REGULAR_EXPRESSIONS
 #include "unicode/ustring.h"
 #include "unicode/unistr.h"
 #include "unicode/uniset.h"
 #include "unicode/uchar.h"
 #include "unicode/uchriter.h"
 #include "unicode/parsepos.h"
 #include "unicode/parseerr.h"
 #include "unicode/regex.h"
 #include "unicode/utf.h"
 #include "unicode/utf16.h"
 #include "patternprops.h"
 #include "putilimp.h"
 #include "cmemory.h"
 #include "cstring.h"
 #include "uvectr32.h"
 #include "uvectr64.h"
 #include "uassert.h"
 #include "ucln_in.h"
 #include "uinvchar.h"
 #include "regeximp.h"
 #include "regexcst.h"   // Contains state table for the regex pattern parser.
                         //   generated by a Perl script.
 #include "regexcmp.h"
 #include "regexst.h"
 #include "regextxt.h"
 U_NAMESPACE_BEGIN
 //------------------------------------------------------------------------------
 //
 //  Constructor.
 //
 //------------------------------------------------------------------------------
 RegexCompile::RegexCompile(RegexPattern *rxp, UErrorCode &status) :
    fParenStack(status), fSetStack(status), fSetOpStack(status)
 {
     // Lazy init of all shared global sets (needed for init()'s empty text)
     RegexStaticSets::initGlobals(&status);
     fStatus           = &status;
     fRXPat            = rxp;
     fScanIndex        = 0;
     fLastChar         = -1;
     fPeekChar         = -1;
     fLineNum          = 1;
     fCharNum          = 0;
     fQuoteMode        = FALSE;
     fInBackslashQuote = FALSE;
     fModeFlags        = fRXPat->fFlags | 0x80000000;
     fEOLComments      = TRUE;
     fMatchOpenParen   = -1;
     fMatchCloseParen  = -1;
     if (U_SUCCESS(status) && U_FAILURE(rxp->fDeferredStatus)) {
         status = rxp->fDeferredStatus;
     }
 }
 static const UChar      chAmp       = 0x26;      // '&'
 static const UChar      chDash      = 0x2d;      // '-'
 //------------------------------------------------------------------------------
 //
 //  Destructor
 //
 //------------------------------------------------------------------------------
 RegexCompile::~RegexCompile() {
 }
 static inline void addCategory(UnicodeSet *set, int32_t value, UErrorCode& ec) {
     set->addAll(UnicodeSet().applyIntPropertyValue(UCHAR_GENERAL_CATEGORY_MASK, value, ec));
 }
 //------------------------------------------------------------------------------
 //
 //  Compile regex pattern.   The state machine for rexexp pattern parsing is here.
 //                           The state tables are hand-written in the file regexcst.txt,
 //                           and converted to the form used here by a perl
 //                           script regexcst.pl
 //
 //------------------------------------------------------------------------------
 void    RegexCompile::compile(
                          const UnicodeString &pat,   // Source pat to be compiled.
                          UParseError &pp,            // Error position info
                          UErrorCode &e)              // Error Code
 {
     fRXPat->fPatternString = new UnicodeString(pat);
     UText patternText = UTEXT_INITIALIZER;
     utext_openConstUnicodeString(&patternText, fRXPat->fPatternString, &e);
     if (U_SUCCESS(e)) {
         compile(&patternText, pp, e);
         utext_close(&patternText);
     }
 }
 //
 //   compile, UText mode
 //     All the work is actually done here.
 //
 void    RegexCompile::compile(
                          UText *pat,                 // Source pat to be compiled.
                          UParseError &pp,            // Error position info
                          UErrorCode &e)              // Error Code
 {
     fStatus             = &e;
     fParseErr           = &pp;
     fStackPtr           = 0;
     fStack[fStackPtr]   = 0;
     if (U_FAILURE(*fStatus)) {
         return;
     }
     // There should be no pattern stuff in the RegexPattern object.  They can not be reused.
     U_ASSERT(fRXPat->fPattern == NULL || utext_nativeLength(fRXPat->fPattern) == 0);
     // Prepare the RegexPattern object to receive the compiled pattern.
     fRXPat->fPattern        = utext_clone(fRXPat->fPattern, pat, FALSE, TRUE, fStatus);
     fRXPat->fStaticSets     = RegexStaticSets::gStaticSets->fPropSets;
     fRXPat->fStaticSets8    = RegexStaticSets::gStaticSets->fPropSets8;
     // Initialize the pattern scanning state machine
     fPatternLength = utext_nativeLength(pat);
     uint16_t                state = 1;
     const RegexTableEl      *tableEl;
     // UREGEX_LITERAL force entire pattern to be treated as a literal string.
     if (fModeFlags & UREGEX_LITERAL) {
         fQuoteMode = TRUE;
     }
     nextChar(fC);                        // Fetch the first char from the pattern string.
     //
     // Main loop for the regex pattern parsing state machine.
     //   Runs once per state transition.
     //   Each time through optionally performs, depending on the state table,
     //      - an advance to the the next pattern char
     //      - an action to be performed.
     //      - pushing or popping a state to/from the local state return stack.
     //   file regexcst.txt is the source for the state table.  The logic behind
     //     recongizing the pattern syntax is there, not here.
     //
     for (;;) {
         //  Bail out if anything has gone wrong.
         //  Regex pattern parsing stops on the first error encountered.
         if (U_FAILURE(*fStatus)) {
             break;
         }
         U_ASSERT(state != 0);
         // Find the state table element that matches the input char from the pattern, or the
         //    class of the input character.  Start with the first table row for this
         //    state, then linearly scan forward until we find a row that matches the
         //    character.  The last row for each state always matches all characters, so
         //    the search will stop there, if not before.
         //
         tableEl = &gRuleParseStateTable[state];
         REGEX_SCAN_DEBUG_PRINTF(("char, line, col = (\'%c\', %d, %d)    state=%s ",
             fC.fChar, fLineNum, fCharNum, RegexStateNames[state]));
         for (;;) {    // loop through table rows belonging to this state, looking for one
                       //   that matches the current input char.
             REGEX_SCAN_DEBUG_PRINTF(("."));
             if (tableEl->fCharClass < 127 && fC.fQuoted == FALSE &&   tableEl->fCharClass == fC.fChar) {
                 // Table row specified an individual character, not a set, and
                 //   the input character is not quoted, and
                 //   the input character matched it.
                 break;
             }
             if (tableEl->fCharClass == 255) {
                 // Table row specified default, match anything character class.
                 break;
             }
             if (tableEl->fCharClass == 254 && fC.fQuoted)  {
                 // Table row specified "quoted" and the char was quoted.
                 break;
             }
             if (tableEl->fCharClass == 253 && fC.fChar == (UChar32)-1)  {
                 // Table row specified eof and we hit eof on the input.
                 break;
             }
             if (tableEl->fCharClass >= 128 && tableEl->fCharClass < 240 &&   // Table specs a char class &&
                 fC.fQuoted == FALSE &&                                       //   char is not escaped &&
                 fC.fChar != (UChar32)-1) {                                   //   char is not EOF
                 U_ASSERT(tableEl->fCharClass <= 137);
                 if (RegexStaticSets::gStaticSets->fRuleSets[tableEl->fCharClass-128].contains(fC.fChar)) {
                     // Table row specified a character class, or set of characters,
                     //   and the current char matches it.
                     break;
                 }
             }
             // No match on this row, advance to the next  row for this state,
             tableEl++;
         }
         REGEX_SCAN_DEBUG_PRINTF(("\n"));
         //
         // We've found the row of the state table that matches the current input
         //   character from the rules string.
         // Perform any action specified  by this row in the state table.
         if (doParseActions(tableEl->fAction) == FALSE) {
             // Break out of the state machine loop if the
             //   the action signalled some kind of error, or
             //   the action was to exit, occurs on normal end-of-rules-input.
             break;
         }
         if (tableEl->fPushState != 0) {
             fStackPtr++;
             if (fStackPtr >= kStackSize) {
                 error(U_REGEX_INTERNAL_ERROR);
                 REGEX_SCAN_DEBUG_PRINTF(("RegexCompile::parse() - state stack overflow.\n"));
                 fStackPtr--;
             }
             fStack[fStackPtr] = tableEl->fPushState;
         }
         //
         //  NextChar.  This is where characters are actually fetched from the pattern.
         //             Happens under control of the 'n' tag in the state table.
         //
         if (tableEl->fNextChar) {
             nextChar(fC);
         }
         // Get the next state from the table entry, or from the
         //   state stack if the next state was specified as "pop".
         if (tableEl->fNextState != 255) {
             state = tableEl->fNextState;
         } else {
             state = fStack[fStackPtr];
             fStackPtr--;
             if (fStackPtr < 0) {
                 // state stack underflow
                 // This will occur if the user pattern has mis-matched parentheses,
                 //   with extra close parens.
                 //
                 fStackPtr++;
                 error(U_REGEX_MISMATCHED_PAREN);
             }
         }
     }
     if (U_FAILURE(*fStatus)) {
         // Bail out if the pattern had errors.
         //   Set stack cleanup:  a successful compile would have left it empty,
         //   but errors can leave temporary sets hanging around.
         while (!fSetStack.empty()) {
             delete (UnicodeSet *)fSetStack.pop();
         }
         return;
     }
     //
     // The pattern has now been read and processed, and the compiled code generated.
     //
     //
     // Compute the number of digits requried for the largest capture group number.
     //
     fRXPat->fMaxCaptureDigits = 1;
     int32_t  n = 10;
     int32_t  groupCount = fRXPat->fGroupMap->size();
     while (n <= groupCount) {
         fRXPat->fMaxCaptureDigits++;
         n *= 10;
     }
     //
     // The pattern's fFrameSize so far has accumulated the requirements for
     //   storage for capture parentheses, counters, etc. that are encountered
     //   in the pattern.  Add space for the two variables that are always
     //   present in the saved state:  the input string position (int64_t) and
     //   the position in the compiled pattern.
     //
     fRXPat->fFrameSize+=RESTACKFRAME_HDRCOUNT;
     //
     // Optimization pass 1: NOPs, back-references, and case-folding
     //
     stripNOPs();
     //
     // Get bounds for the minimum and maximum length of a string that this
     //   pattern can match.  Used to avoid looking for matches in strings that
     //   are too short.
     //
     fRXPat->fMinMatchLen = minMatchLength(3, fRXPat->fCompiledPat->size()-1);
     //
     // Optimization pass 2: match start type
     //
     matchStartType();
     //
     // Set up fast latin-1 range sets
     //
     int32_t numSets = fRXPat->fSets->size();
     fRXPat->fSets8 = new Regex8BitSet[numSets];
     // Null pointer check.
     if (fRXPat->fSets8 == NULL) {
         e = *fStatus = U_MEMORY_ALLOCATION_ERROR;
         return;
     }
     int32_t i;
     for (i=0; i<numSets; i++) {
         UnicodeSet *s = (UnicodeSet *)fRXPat->fSets->elementAt(i);
         fRXPat->fSets8[i].init(s);
     }
 }
 //------------------------------------------------------------------------------
 //
 //  doParseAction        Do some action during regex pattern parsing.
 //                       Called by the parse state machine.
 //
 //                       Generation of the match engine PCode happens here, or
 //                       in functions called from the parse actions defined here.
 //
 //
 //------------------------------------------------------------------------------
 UBool RegexCompile::doParseActions(int32_t action)
 {
     UBool   returnVal = TRUE;
     switch ((Regex_PatternParseAction)action) {
     case doPatStart:
         // Start of pattern compiles to:
         //0   SAVE   2        Fall back to position of FAIL
         //1   jmp    3
         //2   FAIL            Stop if we ever reach here.
         //3   NOP             Dummy, so start of pattern looks the same as
         //                    the start of an ( grouping.
         //4   NOP             Resreved, will be replaced by a save if there are
         //                    OR | operators at the top level
         fRXPat->fCompiledPat->addElement(URX_BUILD(URX_STATE_SAVE, 2), *fStatus);
         fRXPat->fCompiledPat->addElement(URX_BUILD(URX_JMP,  3), *fStatus);
         fRXPat->fCompiledPat->addElement(URX_BUILD(URX_FAIL, 0), *fStatus);
         // Standard open nonCapture paren action emits the two NOPs and
         //   sets up the paren stack frame.
         doParseActions(doOpenNonCaptureParen);
         break;
     case doPatFinish:
         // We've scanned to the end of the pattern
         //  The end of pattern compiles to:
         //        URX_END
         //    which will stop the runtime match engine.
         //  Encountering end of pattern also behaves like a close paren,
         //   and forces fixups of the State Save at the beginning of the compiled pattern
         //   and of any OR operations at the top level.
         //
         handleCloseParen();
         if (fParenStack.size() > 0) {
             // Missing close paren in pattern.
             error(U_REGEX_MISMATCHED_PAREN);
         }
         // add the END operation to the compiled pattern.
         fRXPat->fCompiledPat->addElement(URX_BUILD(URX_END, 0), *fStatus);
         // Terminate the pattern compilation state machine.
         returnVal = FALSE;
         break;
     case doOrOperator:
         // Scanning a '|', as in (A|B)
         {
             // Generate code for any pending literals preceding the '|'
             fixLiterals(FALSE);
             // Insert a SAVE operation at the start of the pattern section preceding
             //   this OR at this level.  This SAVE will branch the match forward
             //   to the right hand side of the OR in the event that the left hand
             //   side fails to match and backtracks.  Locate the position for the
             //   save from the location on the top of the parentheses stack.
             int32_t savePosition = fParenStack.popi();
             int32_t op = (int32_t)fRXPat->fCompiledPat->elementAti(savePosition);
             U_ASSERT(URX_TYPE(op) == URX_NOP);  // original contents of reserved location
             op = URX_BUILD(URX_STATE_SAVE, fRXPat->fCompiledPat->size()+1);
             fRXPat->fCompiledPat->setElementAt(op, savePosition);
             // Append an JMP operation into the compiled pattern.  The operand for
             //  the JMP will eventually be the location following the ')' for the
             //  group.  This will be patched in later, when the ')' is encountered.
             op = URX_BUILD(URX_JMP, 0);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             // Push the position of the newly added JMP op onto the parentheses stack.
             // This registers if for fixup when this block's close paren is encountered.
             fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);
             // Append a NOP to the compiled pattern.  This is the slot reserved
             //   for a SAVE in the event that there is yet another '|' following
             //   this one.
             fRXPat->fCompiledPat->addElement(URX_BUILD(URX_NOP, 0), *fStatus);
             fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);
         }
         break;
     case doOpenCaptureParen:
         // Open Paren.
         //   Compile to a
         //      - NOP, which later may be replaced by a save-state if the
         //         parenthesized group gets a * quantifier, followed by
         //      - START_CAPTURE  n    where n is stack frame offset to the capture group variables.
         //      - NOP, which may later be replaced by a save-state if there
         //             is an '|' alternation within the parens.
         //
         //    Each capture group gets three slots in the save stack frame:
         //         0: Capture Group start position (in input string being matched.)
         //         1: Capture Group end position.
         //         2: Start of Match-in-progress.
         //    The first two locations are for a completed capture group, and are
         //     referred to by back references and the like.
         //    The third location stores the capture start position when an START_CAPTURE is
         //      encountered.  This will be promoted to a completed capture when (and if) the corresponding
         //      END_CAPTURE is encountered.
         {
             fixLiterals();
             fRXPat->fCompiledPat->addElement(URX_BUILD(URX_NOP, 0), *fStatus);
             int32_t  varsLoc    = fRXPat->fFrameSize;    // Reserve three slots in match stack frame.
             fRXPat->fFrameSize += 3;
             int32_t  cop        = URX_BUILD(URX_START_CAPTURE, varsLoc);
             fRXPat->fCompiledPat->addElement(cop, *fStatus);
             fRXPat->fCompiledPat->addElement(URX_BUILD(URX_NOP, 0), *fStatus);
             // On the Parentheses stack, start a new frame and add the postions
             //   of the two NOPs.  Depending on what follows in the pattern, the
             //   NOPs may be changed to SAVE_STATE or JMP ops, with a target
             //   address of the end of the parenthesized group.
             fParenStack.push(fModeFlags, *fStatus);                       // Match mode state
             fParenStack.push(capturing, *fStatus);                        // Frame type.
             fParenStack.push(fRXPat->fCompiledPat->size()-3, *fStatus);   // The first  NOP location
             fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);   // The second NOP loc
             // Save the mapping from group number to stack frame variable position.
             fRXPat->fGroupMap->addElement(varsLoc, *fStatus);
         }
          break;
     case doOpenNonCaptureParen:
         // Open non-caputuring (grouping only) Paren.
         //   Compile to a
         //      - NOP, which later may be replaced by a save-state if the
         //         parenthesized group gets a * quantifier, followed by
         //      - NOP, which may later be replaced by a save-state if there
         //             is an '|' alternation within the parens.
         {
             fixLiterals();
             fRXPat->fCompiledPat->addElement(URX_BUILD(URX_NOP, 0), *fStatus);
             fRXPat->fCompiledPat->addElement(URX_BUILD(URX_NOP, 0), *fStatus);
             // On the Parentheses stack, start a new frame and add the postions
             //   of the two NOPs.
             fParenStack.push(fModeFlags, *fStatus);                       // Match mode state
             fParenStack.push(plain,      *fStatus);                       // Begin a new frame.
             fParenStack.push(fRXPat->fCompiledPat->size()-2, *fStatus);   // The first  NOP location
             fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);   // The second NOP loc
         }
          break;
     case doOpenAtomicParen:
         // Open Atomic Paren.  (?>
         //   Compile to a
         //      - NOP, which later may be replaced if the parenthesized group
         //         has a quantifier, followed by
         //      - STO_SP  save state stack position, so it can be restored at the ")"
         //      - NOP, which may later be replaced by a save-state if there
         //             is an '|' alternation within the parens.
         {
             fixLiterals();
             fRXPat->fCompiledPat->addElement(URX_BUILD(URX_NOP, 0), *fStatus);
             int32_t  varLoc    = fRXPat->fDataSize;    // Reserve a data location for saving the
             fRXPat->fDataSize += 1;                    //  state stack ptr.
             int32_t  stoOp     = URX_BUILD(URX_STO_SP, varLoc);
             fRXPat->fCompiledPat->addElement(stoOp, *fStatus);
             fRXPat->fCompiledPat->addElement(URX_BUILD(URX_NOP, 0), *fStatus);
             // On the Parentheses stack, start a new frame and add the postions
             //   of the two NOPs.  Depending on what follows in the pattern, the
             //   NOPs may be changed to SAVE_STATE or JMP ops, with a target
             //   address of the end of the parenthesized group.
             fParenStack.push(fModeFlags, *fStatus);                       // Match mode state
             fParenStack.push(atomic, *fStatus);                           // Frame type.
             fParenStack.push(fRXPat->fCompiledPat->size()-3, *fStatus);   // The first NOP
             fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);   // The second NOP
         }
         break;
     case doOpenLookAhead:
         // Positive Look-ahead   (?=  stuff  )
         //
         //   Note:   Addition of transparent input regions, with the need to
         //           restore the original regions when failing out of a lookahead
         //           block, complicated this sequence.  Some conbined opcodes
         //           might make sense - or might not, lookahead aren't that common.
         //
         //      Caution:  min match length optimization knows about this
         //               sequence; don't change without making updates there too.
         //
         // Compiles to
         //    1    START_LA     dataLoc     Saves SP, Input Pos
         //    2.   STATE_SAVE   4            on failure of lookahead, goto 4
         //    3    JMP          6           continue ...
         //
         //    4.   LA_END                   Look Ahead failed.  Restore regions.
         //    5.   BACKTRACK                and back track again.
         //
         //    6.   NOP              reserved for use by quantifiers on the block.
         //                          Look-ahead can't have quantifiers, but paren stack
         //                             compile time conventions require the slot anyhow.
         //    7.   NOP              may be replaced if there is are '|' ops in the block.
         //    8.     code for parenthesized stuff.
         //    9.   LA_END
         //
         //  Two data slots are reserved, for saving the stack ptr and the input position.
         {
             fixLiterals();
             int32_t dataLoc = fRXPat->fDataSize;
             fRXPat->fDataSize += 2;
             int32_t op = URX_BUILD(URX_LA_START, dataLoc);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             op = URX_BUILD(URX_STATE_SAVE, fRXPat->fCompiledPat->size()+ 2);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             op = URX_BUILD(URX_JMP, fRXPat->fCompiledPat->size()+ 3);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             op = URX_BUILD(URX_LA_END, dataLoc);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             op = URX_BUILD(URX_BACKTRACK, 0);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             op = URX_BUILD(URX_NOP, 0);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             // On the Parentheses stack, start a new frame and add the postions
             //   of the NOPs.
             fParenStack.push(fModeFlags, *fStatus);                       // Match mode state
             fParenStack.push(lookAhead, *fStatus);                        // Frame type.
             fParenStack.push(fRXPat->fCompiledPat->size()-2, *fStatus);   // The first  NOP location
             fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);   // The second NOP location
         }
         break;
     case doOpenLookAheadNeg:
         // Negated Lookahead.   (?! stuff )
         // Compiles to
         //    1.    START_LA    dataloc
         //    2.    SAVE_STATE  7         // Fail within look-ahead block restores to this state,
         //                                //   which continues with the match.
         //    3.    NOP                   // Std. Open Paren sequence, for possible '|'
         //    4.       code for parenthesized stuff.
         //    5.    END_LA                // Cut back stack, remove saved state from step 2.
         //    6.    BACKTRACK             // code in block succeeded, so neg. lookahead fails.
         //    7.    END_LA                // Restore match region, in case look-ahead was using
         //                                        an alternate (transparent) region.
         {
             fixLiterals();
             int32_t dataLoc = fRXPat->fDataSize;
             fRXPat->fDataSize += 2;
             int32_t op = URX_BUILD(URX_LA_START, dataLoc);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             op = URX_BUILD(URX_STATE_SAVE, 0);    // dest address will be patched later.
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             op = URX_BUILD(URX_NOP, 0);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             // On the Parentheses stack, start a new frame and add the postions
             //   of the StateSave and NOP.
             fParenStack.push(fModeFlags, *fStatus);                       // Match mode state
             fParenStack.push(negLookAhead, *fStatus);                    // Frame type
             fParenStack.push(fRXPat->fCompiledPat->size()-2, *fStatus);   // The STATE_SAVE location
             fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);   // The second NOP location
             // Instructions #5 - #7 will be added when the ')' is encountered.
         }
         break;
     case doOpenLookBehind:
         {
             //   Compile a (?<= look-behind open paren.
             //
             //          Compiles to
             //              0       URX_LB_START     dataLoc
             //              1       URX_LB_CONT      dataLoc
             //              2                        MinMatchLen
             //              3                        MaxMatchLen
             //              4       URX_NOP          Standard '(' boilerplate.
             //              5       URX_NOP          Reserved slot for use with '|' ops within (block).
             //              6         <code for LookBehind expression>
             //              7       URX_LB_END       dataLoc    # Check match len, restore input  len
             //              8       URX_LA_END       dataLoc    # Restore stack, input pos
             //
             //          Allocate a block of matcher data, to contain (when running a match)
             //              0:    Stack ptr on entry
             //              1:    Input Index on entry
             //              2:    Start index of match current match attempt.
             //              3:    Original Input String len.
             // Generate match code for any pending literals.
             fixLiterals();
             // Allocate data space
             int32_t dataLoc = fRXPat->fDataSize;
             fRXPat->fDataSize += 4;
             // Emit URX_LB_START
             int32_t op = URX_BUILD(URX_LB_START, dataLoc);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             // Emit URX_LB_CONT
             op = URX_BUILD(URX_LB_CONT, dataLoc);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             fRXPat->fCompiledPat->addElement(0,  *fStatus);    // MinMatchLength.  To be filled later.
             fRXPat->fCompiledPat->addElement(0,  *fStatus);    // MaxMatchLength.  To be filled later.
             // Emit the NOP
             op = URX_BUILD(URX_NOP, 0);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             // On the Parentheses stack, start a new frame and add the postions
             //   of the URX_LB_CONT and the NOP.
             fParenStack.push(fModeFlags, *fStatus);                       // Match mode state
             fParenStack.push(lookBehind, *fStatus);                       // Frame type
             fParenStack.push(fRXPat->fCompiledPat->size()-2, *fStatus);   // The first NOP location
             fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);   // The 2nd   NOP location
             // The final two instructions will be added when the ')' is encountered.
         }
         break;
     case doOpenLookBehindNeg:
         {
             //   Compile a (?<! negated look-behind open paren.
             //
             //          Compiles to
             //              0       URX_LB_START     dataLoc    # Save entry stack, input len
             //              1       URX_LBN_CONT     dataLoc    # Iterate possible match positions
             //              2                        MinMatchLen
             //              3                        MaxMatchLen
             //              4                        continueLoc (9)
             //              5       URX_NOP          Standard '(' boilerplate.
             //              6       URX_NOP          Reserved slot for use with '|' ops within (block).
             //              7         <code for LookBehind expression>
             //              8       URX_LBN_END      dataLoc    # Check match len, cause a FAIL
             //              9       ...
             //
             //          Allocate a block of matcher data, to contain (when running a match)
             //              0:    Stack ptr on entry
             //              1:    Input Index on entry
             //              2:    Start index of match current match attempt.
             //              3:    Original Input String len.
             // Generate match code for any pending literals.
             fixLiterals();
             // Allocate data space
             int32_t dataLoc = fRXPat->fDataSize;
             fRXPat->fDataSize += 4;
             // Emit URX_LB_START
             int32_t op = URX_BUILD(URX_LB_START, dataLoc);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             // Emit URX_LBN_CONT
             op = URX_BUILD(URX_LBN_CONT, dataLoc);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             fRXPat->fCompiledPat->addElement(0,  *fStatus);    // MinMatchLength.  To be filled later.
             fRXPat->fCompiledPat->addElement(0,  *fStatus);    // MaxMatchLength.  To be filled later.
             fRXPat->fCompiledPat->addElement(0,  *fStatus);    // Continue Loc.    To be filled later.
             // Emit the NOP
             op = URX_BUILD(URX_NOP, 0);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             // On the Parentheses stack, start a new frame and add the postions
             //   of the URX_LB_CONT and the NOP.
             fParenStack.push(fModeFlags, *fStatus);                       // Match mode state
             fParenStack.push(lookBehindN, *fStatus);                      // Frame type
             fParenStack.push(fRXPat->fCompiledPat->size()-2, *fStatus);   // The first NOP location
             fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);   // The 2nd   NOP location
             // The final two instructions will be added when the ')' is encountered.
         }
         break;
     case doConditionalExpr:
         // Conditionals such as (?(1)a:b)
     case doPerlInline:
         // Perl inline-condtionals.  (?{perl code}a|b) We're not perl, no way to do them.
         error(U_REGEX_UNIMPLEMENTED);
         break;
     case doCloseParen:
         handleCloseParen();
         if (fParenStack.size() <= 0) {
             //  Extra close paren, or missing open paren.
             error(U_REGEX_MISMATCHED_PAREN);
         }
         break;
     case doNOP:
         break;
     case doBadOpenParenType:
     case doRuleError:
         error(U_REGEX_RULE_SYNTAX);
         break;
     case doMismatchedParenErr:
         error(U_REGEX_MISMATCHED_PAREN);
         break;
     case doPlus:
         //  Normal '+'  compiles to
         //     1.   stuff to be repeated  (already built)
         //     2.   jmp-sav 1
         //     3.   ...
         //
         //  Or, if the item to be repeated can match a zero length string,
         //     1.   STO_INP_LOC  data-loc
         //     2.      body of stuff to be repeated
         //     3.   JMP_SAV_X    2
         //     4.   ...
         //
         //  Or, if the item to be repeated is simple
         //     1.   Item to be repeated.
         //     2.   LOOP_SR_I    set number  (assuming repeated item is a set ref)
         //     3.   LOOP_C       stack location
         {
             int32_t  topLoc = blockTopLoc(FALSE);        // location of item #1
             int32_t  frameLoc;
             // Check for simple constructs, which may get special optimized code.
             if (topLoc == fRXPat->fCompiledPat->size() - 1) {
                 int32_t repeatedOp = (int32_t)fRXPat->fCompiledPat->elementAti(topLoc);
                 if (URX_TYPE(repeatedOp) == URX_SETREF) {
                     // Emit optimized code for [char set]+
                     int32_t loopOpI = URX_BUILD(URX_LOOP_SR_I, URX_VAL(repeatedOp));
                     fRXPat->fCompiledPat->addElement(loopOpI, *fStatus);
                     frameLoc = fRXPat->fFrameSize;
                     fRXPat->fFrameSize++;
                     int32_t loopOpC = URX_BUILD(URX_LOOP_C, frameLoc);
                     fRXPat->fCompiledPat->addElement(loopOpC, *fStatus);
                     break;
                 }
                 if (URX_TYPE(repeatedOp) == URX_DOTANY ||
                     URX_TYPE(repeatedOp) == URX_DOTANY_ALL ||
                     URX_TYPE(repeatedOp) == URX_DOTANY_UNIX) {
                     // Emit Optimized code for .+ operations.
                     int32_t loopOpI = URX_BUILD(URX_LOOP_DOT_I, 0);
                     if (URX_TYPE(repeatedOp) == URX_DOTANY_ALL) {
                         // URX_LOOP_DOT_I operand is a flag indicating ". matches any" mode.
                         loopOpI |= 1;
                     }
                     if (fModeFlags & UREGEX_UNIX_LINES) {
                         loopOpI |= 2;
                     }
                     fRXPat->fCompiledPat->addElement(loopOpI, *fStatus);
                     frameLoc = fRXPat->fFrameSize;
                     fRXPat->fFrameSize++;
                     int32_t loopOpC = URX_BUILD(URX_LOOP_C, frameLoc);
                     fRXPat->fCompiledPat->addElement(loopOpC, *fStatus);
                     break;
                 }
             }
             // General case.
             // Check for minimum match length of zero, which requires
             //    extra loop-breaking code.
             if (minMatchLength(topLoc, fRXPat->fCompiledPat->size()-1) == 0) {
                 // Zero length match is possible.
                 // Emit the code sequence that can handle it.
                 insertOp(topLoc);
                 frameLoc =  fRXPat->fFrameSize;
                 fRXPat->fFrameSize++;
                 int32_t op = URX_BUILD(URX_STO_INP_LOC, frameLoc);
                 fRXPat->fCompiledPat->setElementAt(op, topLoc);
                 op = URX_BUILD(URX_JMP_SAV_X, topLoc+1);
                 fRXPat->fCompiledPat->addElement(op, *fStatus);
             } else {
                 // Simpler code when the repeated body must match something non-empty
                 int32_t  jmpOp  = URX_BUILD(URX_JMP_SAV, topLoc);
                 fRXPat->fCompiledPat->addElement(jmpOp, *fStatus);
             }
         }
         break;
     case doNGPlus:
         //  Non-greedy '+?'  compiles to
         //     1.   stuff to be repeated  (already built)
         //     2.   state-save  1
         //     3.   ...
         {
             int32_t topLoc      = blockTopLoc(FALSE);
             int32_t saveStateOp = URX_BUILD(URX_STATE_SAVE, topLoc);
             fRXPat->fCompiledPat->addElement(saveStateOp, *fStatus);
         }
         break;
     case doOpt:
         // Normal (greedy) ? quantifier.
         //  Compiles to
         //     1. state save 3
         //     2.    body of optional block
         //     3. ...
         // Insert the state save into the compiled pattern, and we're done.
         {
             int32_t   saveStateLoc = blockTopLoc(TRUE);
             int32_t   saveStateOp  = URX_BUILD(URX_STATE_SAVE, fRXPat->fCompiledPat->size());
             fRXPat->fCompiledPat->setElementAt(saveStateOp, saveStateLoc);
         }
         break;
     case doNGOpt:
         // Non-greedy ?? quantifier
         //   compiles to
         //    1.  jmp   4
         //    2.     body of optional block
         //    3   jmp   5
         //    4.  state save 2
         //    5    ...
         //  This code is less than ideal, with two jmps instead of one, because we can only
         //  insert one instruction at the top of the block being iterated.
         {
             int32_t  jmp1_loc = blockTopLoc(TRUE);
             int32_t  jmp2_loc = fRXPat->fCompiledPat->size();
             int32_t  jmp1_op  = URX_BUILD(URX_JMP, jmp2_loc+1);
             fRXPat->fCompiledPat->setElementAt(jmp1_op, jmp1_loc);
             int32_t  jmp2_op  = URX_BUILD(URX_JMP, jmp2_loc+2);
             fRXPat->fCompiledPat->addElement(jmp2_op, *fStatus);
             int32_t  save_op  = URX_BUILD(URX_STATE_SAVE, jmp1_loc+1);
             fRXPat->fCompiledPat->addElement(save_op, *fStatus);
         }
         break;
     case doStar:
         // Normal (greedy) * quantifier.
         // Compiles to
         //       1.   STATE_SAVE   4
         //       2.      body of stuff being iterated over
         //       3.   JMP_SAV      2
         //       4.   ...
         //
         // Or, if the body is a simple [Set],
         //       1.   LOOP_SR_I    set number
         //       2.   LOOP_C       stack location
         //       ...
         //
         // Or if this is a .*
         //       1.   LOOP_DOT_I    (. matches all mode flag)
         //       2.   LOOP_C        stack location
         //
         // Or, if the body can match a zero-length string, to inhibit infinite loops,
         //       1.   STATE_SAVE   5
         //       2.   STO_INP_LOC  data-loc
         //       3.      body of stuff
         //       4.   JMP_SAV_X    2
         //       5.   ...
         {
             // location of item #1, the STATE_SAVE
             int32_t   topLoc = blockTopLoc(FALSE);
             int32_t   dataLoc = -1;
             // Check for simple *, where the construct being repeated
             //   compiled to single opcode, and might be optimizable.
             if (topLoc == fRXPat->fCompiledPat->size() - 1) {
                 int32_t repeatedOp = (int32_t)fRXPat->fCompiledPat->elementAti(topLoc);
                 if (URX_TYPE(repeatedOp) == URX_SETREF) {
                     // Emit optimized code for a [char set]*
                     int32_t loopOpI = URX_BUILD(URX_LOOP_SR_I, URX_VAL(repeatedOp));
                     fRXPat->fCompiledPat->setElementAt(loopOpI, topLoc);
                     dataLoc = fRXPat->fFrameSize;
                     fRXPat->fFrameSize++;
                     int32_t loopOpC = URX_BUILD(URX_LOOP_C, dataLoc);
                     fRXPat->fCompiledPat->addElement(loopOpC, *fStatus);
                     break;
                 }
                 if (URX_TYPE(repeatedOp) == URX_DOTANY ||
                     URX_TYPE(repeatedOp) == URX_DOTANY_ALL ||
                     URX_TYPE(repeatedOp) == URX_DOTANY_UNIX) {
                     // Emit Optimized code for .* operations.
                     int32_t loopOpI = URX_BUILD(URX_LOOP_DOT_I, 0);
                     if (URX_TYPE(repeatedOp) == URX_DOTANY_ALL) {
                         // URX_LOOP_DOT_I operand is a flag indicating . matches any mode.
                         loopOpI |= 1;
                     }
                     if ((fModeFlags & UREGEX_UNIX_LINES) != 0) {
                         loopOpI |= 2;
                     }
                     fRXPat->fCompiledPat->setElementAt(loopOpI, topLoc);
                     dataLoc = fRXPat->fFrameSize;
                     fRXPat->fFrameSize++;
                     int32_t loopOpC = URX_BUILD(URX_LOOP_C, dataLoc);
                     fRXPat->fCompiledPat->addElement(loopOpC, *fStatus);
                     break;
                 }
             }
             // Emit general case code for this *
             // The optimizations did not apply.
             int32_t   saveStateLoc = blockTopLoc(TRUE);
             int32_t   jmpOp        = URX_BUILD(URX_JMP_SAV, saveStateLoc+1);
             // Check for minimum match length of zero, which requires
             //    extra loop-breaking code.
             if (minMatchLength(saveStateLoc, fRXPat->fCompiledPat->size()-1) == 0) {
                 insertOp(saveStateLoc);
                 dataLoc =  fRXPat->fFrameSize;
                 fRXPat->fFrameSize++;
                 int32_t op = URX_BUILD(URX_STO_INP_LOC, dataLoc);
                 fRXPat->fCompiledPat->setElementAt(op, saveStateLoc+1);
                 jmpOp      = URX_BUILD(URX_JMP_SAV_X, saveStateLoc+2);
             }
             // Locate the position in the compiled pattern where the match will continue
             //   after completing the *.   (4 or 5 in the comment above)
             int32_t continueLoc = fRXPat->fCompiledPat->size()+1;
             // Put together the save state op store it into the compiled code.
             int32_t saveStateOp = URX_BUILD(URX_STATE_SAVE, continueLoc);
             fRXPat->fCompiledPat->setElementAt(saveStateOp, saveStateLoc);
             // Append the URX_JMP_SAV or URX_JMPX operation to the compiled pattern.
             fRXPat->fCompiledPat->addElement(jmpOp, *fStatus);
         }
         break;
     case doNGStar:
         // Non-greedy *? quantifier
         // compiles to
         //     1.   JMP    3
         //     2.      body of stuff being iterated over
         //     3.   STATE_SAVE  2
         //     4    ...
         {
             int32_t     jmpLoc  = blockTopLoc(TRUE);                   // loc  1.
             int32_t     saveLoc = fRXPat->fCompiledPat->size();        // loc  3.
             int32_t     jmpOp   = URX_BUILD(URX_JMP, saveLoc);
             int32_t     stateSaveOp = URX_BUILD(URX_STATE_SAVE, jmpLoc+1);
             fRXPat->fCompiledPat->setElementAt(jmpOp, jmpLoc);
             fRXPat->fCompiledPat->addElement(stateSaveOp, *fStatus);
         }
         break;
     case doIntervalInit:
         // The '{' opening an interval quantifier was just scanned.
         // Init the counter varaiables that will accumulate the values as the digits
         //    are scanned.
         fIntervalLow = 0;
         fIntervalUpper = -1;
         break;
     case doIntevalLowerDigit:
         // Scanned a digit from the lower value of an {lower,upper} interval
         {
             int32_t digitValue = u_charDigitValue(fC.fChar);
             U_ASSERT(digitValue >= 0);
             fIntervalLow = fIntervalLow*10 + digitValue;
             if (fIntervalLow < 0) {
                 error(U_REGEX_NUMBER_TOO_BIG);
             }
         }
         break;
     case doIntervalUpperDigit:
         // Scanned a digit from the upper value of an {lower,upper} interval
         {
             if (fIntervalUpper < 0) {
                 fIntervalUpper = 0;
             }
             int32_t digitValue = u_charDigitValue(fC.fChar);
             U_ASSERT(digitValue >= 0);
             fIntervalUpper = fIntervalUpper*10 + digitValue;
             if (fIntervalUpper < 0) {
                 error(U_REGEX_NUMBER_TOO_BIG);
             }
         }
         break;
     case doIntervalSame:
         // Scanned a single value interval like {27}.  Upper = Lower.
         fIntervalUpper = fIntervalLow;
         break;
     case doInterval:
         // Finished scanning a normal {lower,upper} interval.  Generate the code for it.
         if (compileInlineInterval() == FALSE) {
             compileInterval(URX_CTR_INIT, URX_CTR_LOOP);
         }
         break;
     case doPossessiveInterval:
         // Finished scanning a Possessive {lower,upper}+ interval.  Generate the code for it.
         {
             // Remember the loc for the top of the block being looped over.
             //   (Can not reserve a slot in the compiled pattern at this time, because
             //    compileInterval needs to reserve also, and blockTopLoc can only reserve
             //    once per block.)
             int32_t topLoc = blockTopLoc(FALSE);
             // Produce normal looping code.
             compileInterval(URX_CTR_INIT, URX_CTR_LOOP);
             // Surround the just-emitted normal looping code with a STO_SP ... LD_SP
             //  just as if the loop was inclosed in atomic parentheses.
             // First the STO_SP before the start of the loop
             insertOp(topLoc);
             int32_t  varLoc    = fRXPat->fDataSize;    // Reserve a data location for saving the
             fRXPat->fDataSize += 1;                    //  state stack ptr.
             int32_t  op        = URX_BUILD(URX_STO_SP, varLoc);
             fRXPat->fCompiledPat->setElementAt(op, topLoc);
             int32_t loopOp = (int32_t)fRXPat->fCompiledPat->popi();
             U_ASSERT(URX_TYPE(loopOp) == URX_CTR_LOOP && URX_VAL(loopOp) == topLoc);
             loopOp++;     // point LoopOp after the just-inserted STO_SP
             fRXPat->fCompiledPat->push(loopOp, *fStatus);
             // Then the LD_SP after the end of the loop
             op = URX_BUILD(URX_LD_SP, varLoc);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
         }
         break;
     case doNGInterval:
         // Finished scanning a non-greedy {lower,upper}? interval.  Generate the code for it.
         compileInterval(URX_CTR_INIT_NG, URX_CTR_LOOP_NG);
         break;
     case doIntervalError:
         error(U_REGEX_BAD_INTERVAL);
         break;
     case doLiteralChar:
         // We've just scanned a "normal" character from the pattern,
         literalChar(fC.fChar);
         break;
     case doEscapedLiteralChar:
         // We've just scanned an backslashed escaped character with  no
         //   special meaning.  It represents itself.
         if ((fModeFlags & UREGEX_ERROR_ON_UNKNOWN_ESCAPES) != 0 &&
             ((fC.fChar >= 0x41 && fC.fChar<= 0x5A) ||     // in [A-Z]
             (fC.fChar >= 0x61 && fC.fChar <= 0x7a))) {   // in [a-z]
                error(U_REGEX_BAD_ESCAPE_SEQUENCE);
              }
         literalChar(fC.fChar);
         break;
     case doDotAny:
         // scanned a ".",  match any single character.
         {
             fixLiterals(FALSE);
             int32_t   op;
             if (fModeFlags & UREGEX_DOTALL) {
                 op = URX_BUILD(URX_DOTANY_ALL, 0);
             } else if (fModeFlags & UREGEX_UNIX_LINES) {
                 op = URX_BUILD(URX_DOTANY_UNIX, 0);
             } else {
                 op = URX_BUILD(URX_DOTANY, 0);
             }
             fRXPat->fCompiledPat->addElement(op, *fStatus);
         }
         break;
     case doCaret:
         {
             fixLiterals(FALSE);
             int32_t op = 0;
             if (       (fModeFlags & UREGEX_MULTILINE) == 0 && (fModeFlags & UREGEX_UNIX_LINES) == 0) {
                 op = URX_CARET;
             } else if ((fModeFlags & UREGEX_MULTILINE) != 0 && (fModeFlags & UREGEX_UNIX_LINES) == 0) {
                 op = URX_CARET_M;
             } else if ((fModeFlags & UREGEX_MULTILINE) == 0 && (fModeFlags & UREGEX_UNIX_LINES) != 0) {
                 op = URX_CARET;   // Only testing true start of input.
             } else if ((fModeFlags & UREGEX_MULTILINE) != 0 && (fModeFlags & UREGEX_UNIX_LINES) != 0) {
                 op = URX_CARET_M_UNIX;
             }
             fRXPat->fCompiledPat->addElement(URX_BUILD(op, 0), *fStatus);
         }
         break;
     case doDollar:
         {
             fixLiterals(FALSE);
             int32_t op = 0;
             if (       (fModeFlags & UREGEX_MULTILINE) == 0 && (fModeFlags & UREGEX_UNIX_LINES) == 0) {
                 op = URX_DOLLAR;
             } else if ((fModeFlags & UREGEX_MULTILINE) != 0 && (fModeFlags & UREGEX_UNIX_LINES) == 0) {
                 op = URX_DOLLAR_M;
             } else if ((fModeFlags & UREGEX_MULTILINE) == 0 && (fModeFlags & UREGEX_UNIX_LINES) != 0) {
                 op = URX_DOLLAR_D;
             } else if ((fModeFlags & UREGEX_MULTILINE) != 0 && (fModeFlags & UREGEX_UNIX_LINES) != 0) {
                 op = URX_DOLLAR_MD;
             }
             fRXPat->fCompiledPat->addElement(URX_BUILD(op, 0), *fStatus);
         }
         break;
     case doBackslashA:
         fixLiterals(FALSE);
         fRXPat->fCompiledPat->addElement(URX_BUILD(URX_CARET, 0), *fStatus);
         break;
     case doBackslashB:
         {
             #if  UCONFIG_NO_BREAK_ITERATION==1
             if (fModeFlags & UREGEX_UWORD) {
                 error(U_UNSUPPORTED_ERROR);
             }
             #endif
             fixLiterals(FALSE);
             int32_t op = (fModeFlags & UREGEX_UWORD)? URX_BACKSLASH_BU : URX_BACKSLASH_B;
             fRXPat->fCompiledPat->addElement(URX_BUILD(op, 1), *fStatus);
         }
         break;
     case doBackslashb:
         {
             #if  UCONFIG_NO_BREAK_ITERATION==1
             if (fModeFlags & UREGEX_UWORD) {
                 error(U_UNSUPPORTED_ERROR);
             }
             #endif
             fixLiterals(FALSE);
             int32_t op = (fModeFlags & UREGEX_UWORD)? URX_BACKSLASH_BU : URX_BACKSLASH_B;
             fRXPat->fCompiledPat->addElement(URX_BUILD(op, 0), *fStatus);
         }
         break;
     case doBackslashD:
         fixLiterals(FALSE);
         fRXPat->fCompiledPat->addElement(URX_BUILD(URX_BACKSLASH_D, 1), *fStatus);
         break;
     case doBackslashd:
         fixLiterals(FALSE);
         fRXPat->fCompiledPat->addElement(URX_BUILD(URX_BACKSLASH_D, 0), *fStatus);
         break;
     case doBackslashG:
         fixLiterals(FALSE);
         fRXPat->fCompiledPat->addElement(URX_BUILD(URX_BACKSLASH_G, 0), *fStatus);
         break;
     case doBackslashS:
         fixLiterals(FALSE);
         fRXPat->fCompiledPat->addElement(
             URX_BUILD(URX_STAT_SETREF_N, URX_ISSPACE_SET), *fStatus);
         break;
     case doBackslashs:
         fixLiterals(FALSE);
         fRXPat->fCompiledPat->addElement(
             URX_BUILD(URX_STATIC_SETREF, URX_ISSPACE_SET), *fStatus);
         break;
     case doBackslashW:
         fixLiterals(FALSE);
         fRXPat->fCompiledPat->addElement(
             URX_BUILD(URX_STAT_SETREF_N, URX_ISWORD_SET), *fStatus);
         break;
     case doBackslashw:
         fixLiterals(FALSE);
         fRXPat->fCompiledPat->addElement(
             URX_BUILD(URX_STATIC_SETREF, URX_ISWORD_SET), *fStatus);
         break;
     case doBackslashX:
         fixLiterals(FALSE);
         fRXPat->fCompiledPat->addElement(URX_BUILD(URX_BACKSLASH_X, 0), *fStatus);
         break;
     case doBackslashZ:
         fixLiterals(FALSE);
         fRXPat->fCompiledPat->addElement(URX_BUILD(URX_DOLLAR, 0), *fStatus);
         break;
     case doBackslashz:
         fixLiterals(FALSE);
         fRXPat->fCompiledPat->addElement(URX_BUILD(URX_BACKSLASH_Z, 0), *fStatus);
         break;
     case doEscapeError:
         error(U_REGEX_BAD_ESCAPE_SEQUENCE);
         break;
     case doExit:
         fixLiterals(FALSE);
         returnVal = FALSE;
         break;
     case doProperty:
         {
             fixLiterals(FALSE);
             UnicodeSet *theSet = scanProp();
             compileSet(theSet);
         }
         break;
     case doNamedChar:
         {
             UChar32 c = scanNamedChar();
             literalChar(c);
         }
         break;
     case doBackRef:
         // BackReference.  Somewhat unusual in that the front-end can not completely parse
         //                 the regular expression, because the number of digits to be consumed
         //                 depends on the number of capture groups that have been defined.  So
         //                 we have to do it here instead.
         {
             int32_t  numCaptureGroups = fRXPat->fGroupMap->size();
             int32_t  groupNum = 0;
             UChar32  c        = fC.fChar;
             for (;;) {
                 // Loop once per digit, for max allowed number of digits in a back reference.
                 int32_t digit = u_charDigitValue(c);
                 groupNum = groupNum * 10 + digit;
                 if (groupNum >= numCaptureGroups) {
                     break;
                 }
                 c = peekCharLL();
                 if (RegexStaticSets::gStaticSets->fRuleDigitsAlias->contains(c) == FALSE) {
                     break;
                 }
                 nextCharLL();
             }
             // Scan of the back reference in the source regexp is complete.  Now generate
             //  the compiled code for it.
             // Because capture groups can be forward-referenced by back-references,
             //  we fill the operand with the capture group number.  At the end
             //  of compilation, it will be changed to the variable's location.
             U_ASSERT(groupNum > 0);  // Shouldn't happen.  '\0' begins an octal escape sequence,
                                      //    and shouldn't enter this code path at all.
             fixLiterals(FALSE);
             int32_t  op;
             if (fModeFlags & UREGEX_CASE_INSENSITIVE) {
                 op = URX_BUILD(URX_BACKREF_I, groupNum);
             } else {
                 op = URX_BUILD(URX_BACKREF, groupNum);
             }
             fRXPat->fCompiledPat->addElement(op, *fStatus);
         }
         break;
     case doPossessivePlus:
         // Possessive ++ quantifier.
         // Compiles to
         //       1.   STO_SP
         //       2.      body of stuff being iterated over
         //       3.   STATE_SAVE 5
         //       4.   JMP        2
         //       5.   LD_SP
         //       6.   ...
         //
         //  Note:  TODO:  This is pretty inefficient.  A mass of saved state is built up
         //                then unconditionally discarded.  Perhaps introduce a new opcode.  Ticket 6056
         //
         {
             // Emit the STO_SP
             int32_t   topLoc = blockTopLoc(TRUE);
             int32_t   stoLoc = fRXPat->fDataSize;
             fRXPat->fDataSize++;       // Reserve the data location for storing save stack ptr.
             int32_t   op     = URX_BUILD(URX_STO_SP, stoLoc);
             fRXPat->fCompiledPat->setElementAt(op, topLoc);
             // Emit the STATE_SAVE
             op = URX_BUILD(URX_STATE_SAVE, fRXPat->fCompiledPat->size()+2);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             // Emit the JMP
             op = URX_BUILD(URX_JMP, topLoc+1);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             // Emit the LD_SP
             op = URX_BUILD(URX_LD_SP, stoLoc);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
         }
         break;
     case doPossessiveStar:
         // Possessive *+ quantifier.
         // Compiles to
         //       1.   STO_SP       loc
         //       2.   STATE_SAVE   5
         //       3.      body of stuff being iterated over
         //       4.   JMP          2
         //       5.   LD_SP        loc
         //       6    ...
         // TODO:  do something to cut back the state stack each time through the loop.
         {
             // Reserve two slots at the top of the block.
             int32_t   topLoc = blockTopLoc(TRUE);
             insertOp(topLoc);
             // emit   STO_SP     loc
             int32_t   stoLoc = fRXPat->fDataSize;
             fRXPat->fDataSize++;       // Reserve the data location for storing save stack ptr.
             int32_t   op     = URX_BUILD(URX_STO_SP, stoLoc);
             fRXPat->fCompiledPat->setElementAt(op, topLoc);
             // Emit the SAVE_STATE   5
             int32_t L7 = fRXPat->fCompiledPat->size()+1;
             op = URX_BUILD(URX_STATE_SAVE, L7);
             fRXPat->fCompiledPat->setElementAt(op, topLoc+1);
             // Append the JMP operation.
             op = URX_BUILD(URX_JMP, topLoc+1);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             // Emit the LD_SP       loc
             op = URX_BUILD(URX_LD_SP, stoLoc);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
         }
         break;
     case doPossessiveOpt:
         // Possessive  ?+ quantifier.
         //  Compiles to
         //     1. STO_SP      loc
         //     2. SAVE_STATE  5
         //     3.    body of optional block
         //     4. LD_SP       loc
         //     5. ...
         //
         {
             // Reserve two slots at the top of the block.
             int32_t   topLoc = blockTopLoc(TRUE);
             insertOp(topLoc);
             // Emit the STO_SP
             int32_t   stoLoc = fRXPat->fDataSize;
             fRXPat->fDataSize++;       // Reserve the data location for storing save stack ptr.
             int32_t   op     = URX_BUILD(URX_STO_SP, stoLoc);
             fRXPat->fCompiledPat->setElementAt(op, topLoc);
             // Emit the SAVE_STATE
             int32_t   continueLoc = fRXPat->fCompiledPat->size()+1;
             op = URX_BUILD(URX_STATE_SAVE, continueLoc);
             fRXPat->fCompiledPat->setElementAt(op, topLoc+1);
             // Emit the LD_SP
             op = URX_BUILD(URX_LD_SP, stoLoc);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
         }
         break;
     case doBeginMatchMode:
         fNewModeFlags = fModeFlags;
         fSetModeFlag  = TRUE;
         break;
     case doMatchMode:   //  (?i)    and similar
         {
             int32_t  bit = 0;
             switch (fC.fChar) {
             case 0x69: /* 'i' */   bit = UREGEX_CASE_INSENSITIVE; break;
             case 0x64: /* 'd' */   bit = UREGEX_UNIX_LINES;       break;
             case 0x6d: /* 'm' */   bit = UREGEX_MULTILINE;        break;
             case 0x73: /* 's' */   bit = UREGEX_DOTALL;           break;
             case 0x75: /* 'u' */   bit = 0; /* Unicode casing */  break;
             case 0x77: /* 'w' */   bit = UREGEX_UWORD;            break;
             case 0x78: /* 'x' */   bit = UREGEX_COMMENTS;         break;
             case 0x2d: /* '-' */   fSetModeFlag = FALSE;          break;
             default:
                 U_ASSERT(FALSE);   // Should never happen.  Other chars are filtered out
                                    // by the scanner.
             }
             if (fSetModeFlag) {
                 fNewModeFlags |= bit;
             } else {
                 fNewModeFlags &= ~bit;
             }
         }
         break;
     case doSetMatchMode:
         // Emit code to match any pending literals, using the not-yet changed match mode.
         fixLiterals();
         // We've got a (?i) or similar.  The match mode is being changed, but
         //   the change is not scoped to a parenthesized block.
         U_ASSERT(fNewModeFlags < 0);
         fModeFlags = fNewModeFlags;
         break;
     case doMatchModeParen:
         // We've got a (?i: or similar.  Begin a parenthesized block, save old
         //   mode flags so they can be restored at the close of the block.
         //
         //   Compile to a
         //      - NOP, which later may be replaced by a save-state if the
         //         parenthesized group gets a * quantifier, followed by
         //      - NOP, which may later be replaced by a save-state if there
         //             is an '|' alternation within the parens.
         {
             fixLiterals(FALSE);
             fRXPat->fCompiledPat->addElement(URX_BUILD(URX_NOP, 0), *fStatus);
             fRXPat->fCompiledPat->addElement(URX_BUILD(URX_NOP, 0), *fStatus);
             // On the Parentheses stack, start a new frame and add the postions
             //   of the two NOPs (a normal non-capturing () frame, except for the
             //   saving of the orignal mode flags.)
             fParenStack.push(fModeFlags, *fStatus);
             fParenStack.push(flags, *fStatus);                            // Frame Marker
             fParenStack.push(fRXPat->fCompiledPat->size()-2, *fStatus);   // The first NOP
             fParenStack.push(fRXPat->fCompiledPat->size()-1, *fStatus);   // The second NOP
             // Set the current mode flags to the new values.
             U_ASSERT(fNewModeFlags < 0);
             fModeFlags = fNewModeFlags;
         }
         break;
     case doBadModeFlag:
         error(U_REGEX_INVALID_FLAG);
         break;
     case doSuppressComments:
         // We have just scanned a '(?'.  We now need to prevent the character scanner from
         // treating a '#' as a to-the-end-of-line comment.
         //   (This Perl compatibility just gets uglier and uglier to do...)
         fEOLComments = FALSE;
         break;
     case doSetAddAmp:
         {
           UnicodeSet *set = (UnicodeSet *)fSetStack.peek();
           set->add(chAmp);
         }
         break;
     case doSetAddDash:
         {
           UnicodeSet *set = (UnicodeSet *)fSetStack.peek();
           set->add(chDash);
         }
         break;
      case doSetBackslash_s:
         {
          UnicodeSet *set = (UnicodeSet *)fSetStack.peek();
          set->addAll(*RegexStaticSets::gStaticSets->fPropSets[URX_ISSPACE_SET]);
          break;
         }
      case doSetBackslash_S:
         {
             UnicodeSet *set = (UnicodeSet *)fSetStack.peek();
             UnicodeSet SSet(*RegexStaticSets::gStaticSets->fPropSets[URX_ISSPACE_SET]);
             SSet.complement();
             set->addAll(SSet);
             break;
         }
     case doSetBackslash_d:
         {
             UnicodeSet *set = (UnicodeSet *)fSetStack.peek();
             // TODO - make a static set, ticket 6058.
             addCategory(set, U_GC_ND_MASK, *fStatus);
             break;
         }
     case doSetBackslash_D:
         {
             UnicodeSet *set = (UnicodeSet *)fSetStack.peek();
             UnicodeSet digits;
             // TODO - make a static set, ticket 6058.
             digits.applyIntPropertyValue(UCHAR_GENERAL_CATEGORY_MASK, U_GC_ND_MASK, *fStatus);
             digits.complement();
             set->addAll(digits);
             break;
         }
     case doSetBackslash_w:
         {
             UnicodeSet *set = (UnicodeSet *)fSetStack.peek();
             set->addAll(*RegexStaticSets::gStaticSets->fPropSets[URX_ISWORD_SET]);
             break;
         }
     case doSetBackslash_W:
         {
             UnicodeSet *set = (UnicodeSet *)fSetStack.peek();
             UnicodeSet SSet(*RegexStaticSets::gStaticSets->fPropSets[URX_ISWORD_SET]);
             SSet.complement();
             set->addAll(SSet);
             break;
         }
     case doSetBegin:
         fixLiterals(FALSE);
         fSetStack.push(new UnicodeSet(), *fStatus);
         fSetOpStack.push(setStart, *fStatus);
         if ((fModeFlags & UREGEX_CASE_INSENSITIVE) != 0) {
             fSetOpStack.push(setCaseClose, *fStatus);
         }
         break;
     case doSetBeginDifference1:
         //  We have scanned something like [[abc]-[
         //  Set up a new UnicodeSet for the set beginning with the just-scanned '['
         //  Push a Difference operator, which will cause the new set to be subtracted from what
         //    went before once it is created.
         setPushOp(setDifference1);
         fSetOpStack.push(setStart, *fStatus);
         if ((fModeFlags & UREGEX_CASE_INSENSITIVE) != 0) {
             fSetOpStack.push(setCaseClose, *fStatus);
         }
         break;
     case doSetBeginIntersection1:
         //  We have scanned something like  [[abc]&[
         //   Need both the '&' operator and the open '[' operator.
         setPushOp(setIntersection1);
         fSetOpStack.push(setStart, *fStatus);
         if ((fModeFlags & UREGEX_CASE_INSENSITIVE) != 0) {
             fSetOpStack.push(setCaseClose, *fStatus);
         }
         break;
     case doSetBeginUnion:
         //  We have scanned something like  [[abc][
         //     Need to handle the union operation explicitly [[abc] | [
         setPushOp(setUnion);
         fSetOpStack.push(setStart, *fStatus);
         if ((fModeFlags & UREGEX_CASE_INSENSITIVE) != 0) {
             fSetOpStack.push(setCaseClose, *fStatus);
         }
         break;
     case doSetDifference2:
         // We have scanned something like [abc--
         //   Consider this to unambiguously be a set difference operator.
         setPushOp(setDifference2);
         break;
     case doSetEnd:
         // Have encountered the ']' that closes a set.
         //    Force the evaluation of any pending operations within this set,
         //    leave the completed set on the top of the set stack.
         setEval(setEnd);
         U_ASSERT(fSetOpStack.peeki()==setStart);
         fSetOpStack.popi();
         break;
     case doSetFinish:
         {
         // Finished a complete set expression, including all nested sets.
         //   The close bracket has already triggered clearing out pending set operators,
         //    the operator stack should be empty and the operand stack should have just
         //    one entry, the result set.
         U_ASSERT(fSetOpStack.empty());
         UnicodeSet *theSet = (UnicodeSet *)fSetStack.pop();
         U_ASSERT(fSetStack.empty());
         compileSet(theSet);
         break;
         }
     case doSetIntersection2:
         // Have scanned something like [abc&&
         setPushOp(setIntersection2);
         break;
     case doSetLiteral:
         // Union the just-scanned literal character into the set being built.
         //    This operation is the highest precedence set operation, so we can always do
         //    it immediately, without waiting to see what follows.  It is necessary to perform
         //    any pending '-' or '&' operation first, because these have the same precedence
         //    as union-ing in a literal'
         {
             setEval(setUnion);
             UnicodeSet *s = (UnicodeSet *)fSetStack.peek();
             s->add(fC.fChar);
             fLastSetLiteral = fC.fChar;
             break;
         }
     case doSetLiteralEscaped:
         // A back-slash escaped literal character was encountered.
         // Processing is the same as with setLiteral, above, with the addition of
         //  the optional check for errors on escaped ASCII letters.
         {
             if ((fModeFlags & UREGEX_ERROR_ON_UNKNOWN_ESCAPES) != 0 &&
                 ((fC.fChar >= 0x41 && fC.fChar<= 0x5A) ||     // in [A-Z]
                  (fC.fChar >= 0x61 && fC.fChar <= 0x7a))) {   // in [a-z]
                 error(U_REGEX_BAD_ESCAPE_SEQUENCE);
             }
             setEval(setUnion);
             UnicodeSet *s = (UnicodeSet *)fSetStack.peek();
             s->add(fC.fChar);
             fLastSetLiteral = fC.fChar;
             break;
         }
         case doSetNamedChar:
         // Scanning a \N{UNICODE CHARACTER NAME}
         //  Aside from the source of the character, the processing is identical to doSetLiteral,
         //    above.
         {
             UChar32  c = scanNamedChar();
             setEval(setUnion);
             UnicodeSet *s = (UnicodeSet *)fSetStack.peek();
             s->add(c);
             fLastSetLiteral = c;
             break;
         }
     case doSetNamedRange:
         // We have scanned literal-\N{CHAR NAME}.  Add the range to the set.
         // The left character is already in the set, and is saved in fLastSetLiteral.
         // The right side needs to be picked up, the scan is at the 'N'.
         // Lower Limit > Upper limit being an error matches both Java
         //        and ICU UnicodeSet behavior.
         {
             UChar32  c = scanNamedChar();
             if (U_SUCCESS(*fStatus) && fLastSetLiteral > c) {
                 error(U_REGEX_INVALID_RANGE);
             }
             UnicodeSet *s = (UnicodeSet *)fSetStack.peek();
             s->add(fLastSetLiteral, c);
             fLastSetLiteral = c;
             break;
         }
     case  doSetNegate:
         // Scanned a '^' at the start of a set.
         // Push the negation operator onto the set op stack.
         // A twist for case-insensitive matching:
         //   the case closure operation must happen _before_ negation.
         //   But the case closure operation will already be on the stack if it's required.
         //   This requires checking for case closure, and swapping the stack order
         //    if it is present.
         {
             int32_t  tosOp = fSetOpStack.peeki();
             if (tosOp == setCaseClose) {
                 fSetOpStack.popi();
                 fSetOpStack.push(setNegation, *fStatus);
                 fSetOpStack.push(setCaseClose, *fStatus);
             } else {
                 fSetOpStack.push(setNegation, *fStatus);
             }
         }
         break;
     case doSetNoCloseError:
         error(U_REGEX_MISSING_CLOSE_BRACKET);
         break;
     case doSetOpError:
         error(U_REGEX_RULE_SYNTAX);   //  -- or && at the end of a set.  Illegal.
         break;
     case doSetPosixProp:
         {
             UnicodeSet *s = scanPosixProp();
             if (s != NULL) {
                 UnicodeSet *tos = (UnicodeSet *)fSetStack.peek();
                 tos->addAll(*s);
                 delete s;
             }  // else error.  scanProp() reported the error status already.
         }
         break;
     case doSetProp:
         //  Scanned a \p \P within [brackets].
         {
             UnicodeSet *s = scanProp();
             if (s != NULL) {
                 UnicodeSet *tos = (UnicodeSet *)fSetStack.peek();
                 tos->addAll(*s);
                 delete s;
             }  // else error.  scanProp() reported the error status already.
         }
         break;
     case doSetRange:
         // We have scanned literal-literal.  Add the range to the set.
         // The left character is already in the set, and is saved in fLastSetLiteral.
         // The right side is the current character.
         // Lower Limit > Upper limit being an error matches both Java
         //        and ICU UnicodeSet behavior.
         {
         if (fLastSetLiteral > fC.fChar) {
             error(U_REGEX_INVALID_RANGE);
         }
         UnicodeSet *s = (UnicodeSet *)fSetStack.peek();
         s->add(fLastSetLiteral, fC.fChar);
         break;
         }
     default:
         U_ASSERT(FALSE);
         error(U_REGEX_INTERNAL_ERROR);
         break;
     }
     if (U_FAILURE(*fStatus)) {
         returnVal = FALSE;
     }
     return returnVal;
 }
 //------------------------------------------------------------------------------
 //
 //   literalChar           We've encountered a literal character from the pattern,
 //                             or an escape sequence that reduces to a character.
 //                         Add it to the string containing all literal chars/strings from
 //                             the pattern.
 //
 //------------------------------------------------------------------------------
 void RegexCompile::literalChar(UChar32 c)  {
     fLiteralChars.append(c);
 }
 //------------------------------------------------------------------------------
 //
 //    fixLiterals           When compiling something that can follow a literal
 //                          string in a pattern, emit the code to match the
 //                          accumulated literal string.
 //
 //                          Optionally, split the last char of the string off into
 //                          a single "ONE_CHAR" operation, so that quantifiers can
 //                          apply to that char alone.  Example:   abc*
 //                          The * must apply to the 'c' only.
 //
 //------------------------------------------------------------------------------
 void    RegexCompile::fixLiterals(UBool split) {
     int32_t  op = 0;                       // An op from/for the compiled pattern.
     // If no literal characters have been scanned but not yet had code generated
     //   for them, nothing needs to be done.
     if (fLiteralChars.length() == 0) {
         return;
     }
     int32_t indexOfLastCodePoint = fLiteralChars.moveIndex32(fLiteralChars.length(), -1);
     UChar32 lastCodePoint = fLiteralChars.char32At(indexOfLastCodePoint);
     // Split:  We need to  ensure that the last item in the compiled pattern
     //     refers only to the last literal scanned in the pattern, so that
     //     quantifiers (*, +, etc.) affect only it, and not a longer string.
     //     Split before case folding for case insensitive matches.
     if (split) {
         fLiteralChars.truncate(indexOfLastCodePoint);
         fixLiterals(FALSE);   // Recursive call, emit code to match the first part of the string.
                               //  Note that the truncated literal string may be empty, in which case
                               //  nothing will be emitted.
         literalChar(lastCodePoint);  // Re-add the last code point as if it were a new literal.
         fixLiterals(FALSE);          // Second recursive call, code for the final code point.
         return;
     }
     // If we are doing case-insensitive matching, case fold the string.  This may expand
     //   the string, e.g. the German sharp-s turns into "ss"
     if (fModeFlags & UREGEX_CASE_INSENSITIVE) {
         fLiteralChars.foldCase();
         indexOfLastCodePoint = fLiteralChars.moveIndex32(fLiteralChars.length(), -1);
         lastCodePoint = fLiteralChars.char32At(indexOfLastCodePoint);
     }
     if (indexOfLastCodePoint == 0) {
         // Single character, emit a URX_ONECHAR op to match it.
         if ((fModeFlags & UREGEX_CASE_INSENSITIVE) &&
                  u_hasBinaryProperty(lastCodePoint, UCHAR_CASE_SENSITIVE)) {
             op = URX_BUILD(URX_ONECHAR_I, lastCodePoint);
         } else {
             op = URX_BUILD(URX_ONECHAR, lastCodePoint);
         }
         fRXPat->fCompiledPat->addElement(op, *fStatus);
     } else {
         // Two or more chars, emit a URX_STRING to match them.
         if (fModeFlags & UREGEX_CASE_INSENSITIVE) {
             op = URX_BUILD(URX_STRING_I, fRXPat->fLiteralText.length());
         } else {
             // TODO here:  add optimization to split case sensitive strings of length two
             //             into two single char ops, for efficiency.
             op = URX_BUILD(URX_STRING, fRXPat->fLiteralText.length());
         }
         fRXPat->fCompiledPat->addElement(op, *fStatus);
         op = URX_BUILD(URX_STRING_LEN, fLiteralChars.length());
         fRXPat->fCompiledPat->addElement(op, *fStatus);
         // Add this string into the accumulated strings of the compiled pattern.
         fRXPat->fLiteralText.append(fLiteralChars);
     }
     fLiteralChars.remove();
 }
 //------------------------------------------------------------------------------
 //
 //   insertOp()             Insert a slot for a new opcode into the already
 //                          compiled pattern code.
 //
 //                          Fill the slot with a NOP.  Our caller will replace it
 //                          with what they really wanted.
 //
 //------------------------------------------------------------------------------
 void   RegexCompile::insertOp(int32_t where) {
     UVector64 *code = fRXPat->fCompiledPat;
     U_ASSERT(where>0 && where < code->size());
     int32_t  nop = URX_BUILD(URX_NOP, 0);
     code->insertElementAt(nop, where, *fStatus);
     // Walk through the pattern, looking for any ops with targets that
     //  were moved down by the insert.  Fix them.
     int32_t loc;
     for (loc=0; loc<code->size(); loc++) {
         int32_t op = (int32_t)code->elementAti(loc);
         int32_t opType = URX_TYPE(op);
         int32_t opValue = URX_VAL(op);
         if ((opType == URX_JMP         ||
             opType == URX_JMPX         ||
             opType == URX_STATE_SAVE   ||
             opType == URX_CTR_LOOP     ||
             opType == URX_CTR_LOOP_NG  ||
             opType == URX_JMP_SAV      ||
             opType == URX_JMP_SAV_X    ||
             opType == URX_RELOC_OPRND)    && opValue > where) {
             // Target location for this opcode is after the insertion point and
             //   needs to be incremented to adjust for the insertion.
             opValue++;
             op = URX_BUILD(opType, opValue);
             code->setElementAt(op, loc);
         }
     }
     // Now fix up the parentheses stack.  All positive values in it are locations in
     //  the compiled pattern.   (Negative values are frame boundaries, and don't need fixing.)
     for (loc=0; loc<fParenStack.size(); loc++) {
         int32_t x = fParenStack.elementAti(loc);
         U_ASSERT(x < code->size());
         if (x>where) {
             x++;
             fParenStack.setElementAt(x, loc);
         }
     }
     if (fMatchCloseParen > where) {
         fMatchCloseParen++;
     }
     if (fMatchOpenParen > where) {
         fMatchOpenParen++;
     }
 }
 //------------------------------------------------------------------------------
 //
 //   blockTopLoc()          Find or create a location in the compiled pattern
 //                          at the start of the operation or block that has
 //                          just been compiled.  Needed when a quantifier (* or
 //                          whatever) appears, and we need to add an operation
 //                          at the start of the thing being quantified.
 //
 //                          (Parenthesized Blocks) have a slot with a NOP that
 //                          is reserved for this purpose.  .* or similar don't
 //                          and a slot needs to be added.
 //
 //       parameter reserveLoc   :  TRUE -  ensure that there is space to add an opcode
 //                                         at the returned location.
 //                                 FALSE - just return the address,
 //                                         do not reserve a location there.
 //
 //------------------------------------------------------------------------------
 int32_t   RegexCompile::blockTopLoc(UBool reserveLoc) {
     int32_t   theLoc;
     fixLiterals(TRUE);  // Emit code for any pending literals.
                         //   If last item was a string, emit separate op for the its last char.
     if (fRXPat->fCompiledPat->size() == fMatchCloseParen)
     {
         // The item just processed is a parenthesized block.
         theLoc = fMatchOpenParen;   // A slot is already reserved for us.
         U_ASSERT(theLoc > 0);
         U_ASSERT(URX_TYPE(((uint32_t)fRXPat->fCompiledPat->elementAti(theLoc))) == URX_NOP);
     }
     else {
         // Item just compiled is a single thing, a ".", or a single char, a string or a set reference.
         // No slot for STATE_SAVE was pre-reserved in the compiled code.
         // We need to make space now.
         theLoc = fRXPat->fCompiledPat->size()-1;
         int32_t opAtTheLoc = (int32_t)fRXPat->fCompiledPat->elementAti(theLoc);
         if (URX_TYPE(opAtTheLoc) == URX_STRING_LEN) {
             // Strings take two opcode, we want the position of the first one.
             // We can have a string at this point if a single character case-folded to two.
             theLoc--;
         }
         if (reserveLoc) {
             int32_t  nop = URX_BUILD(URX_NOP, 0);
             fRXPat->fCompiledPat->insertElementAt(nop, theLoc, *fStatus);
         }
     }
     return theLoc;
 }
 //------------------------------------------------------------------------------
 //
 //    handleCloseParen      When compiling a close paren, we need to go back
 //                          and fix up any JMP or SAVE operations within the
 //                          parenthesized block that need to target the end
 //                          of the block.  The locations of these are kept on
 //                          the paretheses stack.
 //
 //                          This function is called both when encountering a
 //                          real ) and at the end of the pattern.
 //
 //------------------------------------------------------------------------------
 void  RegexCompile::handleCloseParen() {
     int32_t   patIdx;
     int32_t   patOp;
     if (fParenStack.size() <= 0) {
         error(U_REGEX_MISMATCHED_PAREN);
         return;
     }
     // Emit code for any pending literals.
     fixLiterals(FALSE);
     // Fixup any operations within the just-closed parenthesized group
     //    that need to reference the end of the (block).
     //    (The first one popped from the stack is an unused slot for
     //     alternation (OR) state save, but applying the fixup to it does no harm.)
     for (;;) {
         patIdx = fParenStack.popi();
         if (patIdx < 0) {
             // value < 0 flags the start of the frame on the paren stack.
             break;
         }
         U_ASSERT(patIdx>0 && patIdx <= fRXPat->fCompiledPat->size());
         patOp = (int32_t)fRXPat->fCompiledPat->elementAti(patIdx);
         U_ASSERT(URX_VAL(patOp) == 0);          // Branch target for JMP should not be set.
         patOp |= fRXPat->fCompiledPat->size();  // Set it now.
         fRXPat->fCompiledPat->setElementAt(patOp, patIdx);
         fMatchOpenParen     = patIdx;
     }
     //  At the close of any parenthesized block, restore the match mode flags  to
     //  the value they had at the open paren.  Saved value is
     //  at the top of the paren stack.
     fModeFlags = fParenStack.popi();
     U_ASSERT(fModeFlags < 0);
     // DO any additional fixups, depending on the specific kind of
     // parentesized grouping this is
     switch (patIdx) {
     case plain:
     case flags:
         // No additional fixups required.
         //   (Grouping-only parentheses)
         break;
     case capturing:
         // Capturing Parentheses.
         //   Insert a End Capture op into the pattern.
         //   The frame offset of the variables for this cg is obtained from the
         //       start capture op and put it into the end-capture op.
         {
             int32_t   captureOp = (int32_t)fRXPat->fCompiledPat->elementAti(fMatchOpenParen+1);
             U_ASSERT(URX_TYPE(captureOp) == URX_START_CAPTURE);
             int32_t   frameVarLocation = URX_VAL(captureOp);
             int32_t   endCaptureOp = URX_BUILD(URX_END_CAPTURE, frameVarLocation);
             fRXPat->fCompiledPat->addElement(endCaptureOp, *fStatus);
         }
         break;
     case atomic:
         // Atomic Parenthesis.
         //   Insert a LD_SP operation to restore the state stack to the position
         //   it was when the atomic parens were entered.
         {
             int32_t   stoOp = (int32_t)fRXPat->fCompiledPat->elementAti(fMatchOpenParen+1);
             U_ASSERT(URX_TYPE(stoOp) == URX_STO_SP);
             int32_t   stoLoc = URX_VAL(stoOp);
             int32_t   ldOp   = URX_BUILD(URX_LD_SP, stoLoc);
             fRXPat->fCompiledPat->addElement(ldOp, *fStatus);
         }
         break;
     case lookAhead:
         {
             int32_t  startOp = (int32_t)fRXPat->fCompiledPat->elementAti(fMatchOpenParen-5);
             U_ASSERT(URX_TYPE(startOp) == URX_LA_START);
             int32_t dataLoc  = URX_VAL(startOp);
             int32_t op       = URX_BUILD(URX_LA_END, dataLoc);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
         }
         break;
     case negLookAhead:
         {
             // See comment at doOpenLookAheadNeg
             int32_t  startOp = (int32_t)fRXPat->fCompiledPat->elementAti(fMatchOpenParen-1);
             U_ASSERT(URX_TYPE(startOp) == URX_LA_START);
             int32_t dataLoc  = URX_VAL(startOp);
             int32_t op       = URX_BUILD(URX_LA_END, dataLoc);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             op               = URX_BUILD(URX_BACKTRACK, 0);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             op               = URX_BUILD(URX_LA_END, dataLoc);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             // Patch the URX_SAVE near the top of the block.
             // The destination of the SAVE is the final LA_END that was just added.
             int32_t saveOp   = (int32_t)fRXPat->fCompiledPat->elementAti(fMatchOpenParen);
             U_ASSERT(URX_TYPE(saveOp) == URX_STATE_SAVE);
             int32_t dest     = fRXPat->fCompiledPat->size()-1;
             saveOp           = URX_BUILD(URX_STATE_SAVE, dest);
             fRXPat->fCompiledPat->setElementAt(saveOp, fMatchOpenParen);
         }
         break;
     case lookBehind:
         {
             // See comment at doOpenLookBehind.
             // Append the URX_LB_END and URX_LA_END to the compiled pattern.
             int32_t  startOp = (int32_t)fRXPat->fCompiledPat->elementAti(fMatchOpenParen-4);
             U_ASSERT(URX_TYPE(startOp) == URX_LB_START);
             int32_t dataLoc  = URX_VAL(startOp);
             int32_t op       = URX_BUILD(URX_LB_END, dataLoc);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
                     op       = URX_BUILD(URX_LA_END, dataLoc);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             // Determine the min and max bounds for the length of the
             //  string that the pattern can match.
             //  An unbounded upper limit is an error.
             int32_t patEnd   = fRXPat->fCompiledPat->size() - 1;
             int32_t minML    = minMatchLength(fMatchOpenParen, patEnd);
             int32_t maxML    = maxMatchLength(fMatchOpenParen, patEnd);
             if (maxML == INT32_MAX) {
                 error(U_REGEX_LOOK_BEHIND_LIMIT);
                 break;
             }
             U_ASSERT(minML <= maxML);
             // Insert the min and max match len bounds into the URX_LB_CONT op that
             //  appears at the top of the look-behind block, at location fMatchOpenParen+1
             fRXPat->fCompiledPat->setElementAt(minML,  fMatchOpenParen-2);
             fRXPat->fCompiledPat->setElementAt(maxML,  fMatchOpenParen-1);
         }
         break;
     case lookBehindN:
         {
             // See comment at doOpenLookBehindNeg.
             // Append the URX_LBN_END to the compiled pattern.
             int32_t  startOp = (int32_t)fRXPat->fCompiledPat->elementAti(fMatchOpenParen-5);
             U_ASSERT(URX_TYPE(startOp) == URX_LB_START);
             int32_t dataLoc  = URX_VAL(startOp);
             int32_t op       = URX_BUILD(URX_LBN_END, dataLoc);
             fRXPat->fCompiledPat->addElement(op, *fStatus);
             // Determine the min and max bounds for the length of the
             //  string that the pattern can match.
             //  An unbounded upper limit is an error.
             int32_t patEnd   = fRXPat->fCompiledPat->size() - 1;
             int32_t minML    = minMatchLength(fMatchOpenParen, patEnd);
             int32_t maxML    = maxMatchLength(fMatchOpenParen, patEnd);
             if (maxML == INT32_MAX) {
                 error(U_REGEX_LOOK_BEHIND_LIMIT);
                 break;
             }
             U_ASSERT(minML <= maxML);
             // Insert the min and max match len bounds into the URX_LB_CONT op that
             //  appears at the top of the look-behind block, at location fMatchOpenParen+1
             fRXPat->fCompiledPat->setElementAt(minML,  fMatchOpenParen-3);
             fRXPat->fCompiledPat->setElementAt(maxML,  fMatchOpenParen-2);
             // Insert the pattern location to continue at after a successful match
             //  as the last operand of the URX_LBN_CONT
             op = URX_BUILD(URX_RELOC_OPRND, fRXPat->fCompiledPat->size());
             fRXPat->fCompiledPat->setElementAt(op,  fMatchOpenParen-1);
         }
         break;
     default:
         U_ASSERT(FALSE);
     }
     // remember the next location in the compiled pattern.
     // The compilation of Quantifiers will look at this to see whether its looping
     //   over a parenthesized block or a single item
     fMatchCloseParen = fRXPat->fCompiledPat->size();
 }
 //------------------------------------------------------------------------------
 //
 //   compileSet       Compile the pattern operations for a reference to a
 //                    UnicodeSet.
 //
 //------------------------------------------------------------------------------
 void        RegexCompile::compileSet(UnicodeSet *theSet)
 {
     if (theSet == NULL) {
         return;
     }
     //  Remove any strings from the set.
     //  There shoudn't be any, but just in case.
     //     (Case Closure can add them; if we had a simple case closure avaialble that
     //      ignored strings, that would be better.)
     theSet->removeAllStrings();
     int32_t  setSize = theSet->size();
     switch (setSize) {
     case 0:
         {
             // Set of no elements.   Always fails to match.
             fRXPat->fCompiledPat->addElement(URX_BUILD(URX_BACKTRACK, 0), *fStatus);
             delete theSet;
         }
         break;
     case 1:
         {
             // The set contains only a single code point.  Put it into
             //   the compiled pattern as a single char operation rather
             //   than a set, and discard the set itself.
             literalChar(theSet->charAt(0));
             delete theSet;
         }
         break;
     default:
         {
             //  The set contains two or more chars.  (the normal case)
             //  Put it into the compiled pattern as a set.
             int32_t setNumber = fRXPat->fSets->size();
             fRXPat->fSets->addElement(theSet, *fStatus);
             int32_t setOp = URX_BUILD(URX_SETREF, setNumber);
             fRXPat->fCompiledPat->addElement(setOp, *fStatus);
         }
     }
 }
 //------------------------------------------------------------------------------
 //
 //   compileInterval    Generate the code for a {min, max} style interval quantifier.
 //                      Except for the specific opcodes used, the code is the same
 //                      for all three types (greedy, non-greedy, possessive) of
 //                      intervals.  The opcodes are supplied as parameters.
 //                      (There are two sets of opcodes - greedy & possessive use the
 //                      same ones, while non-greedy has it's own.)
 //
 //                      The code for interval loops has this form:
 //                         0  CTR_INIT   counter loc (in stack frame)
 //                         1             5  patt address of CTR_LOOP at bottom of block
 //                         2             min count
 //                         3             max count   (-1 for unbounded)
 //                         4  ...        block to be iterated over
 //                         5  CTR_LOOP
 //
 //                       In
 //------------------------------------------------------------------------------
 void        RegexCompile::compileInterval(int32_t InitOp,  int32_t LoopOp)
 {
     // The CTR_INIT op at the top of the block with the {n,m} quantifier takes
     //   four slots in the compiled code.  Reserve them.
     int32_t   topOfBlock = blockTopLoc(TRUE);
     insertOp(topOfBlock);
     insertOp(topOfBlock);
     insertOp(topOfBlock);
     // The operands for the CTR_INIT opcode include the index in the matcher data
     //   of the counter.  Allocate it now. There are two data items
     //        counterLoc   -->  Loop counter
     //               +1    -->  Input index (for breaking non-progressing loops)
     //                          (Only present if unbounded upper limit on loop)
     int32_t   counterLoc = fRXPat->fFrameSize;
     fRXPat->fFrameSize++;
     if (fIntervalUpper < 0) {
         fRXPat->fFrameSize++;
     }
     int32_t   op = URX_BUILD(InitOp, counterLoc);
     fRXPat->fCompiledPat->setElementAt(op, topOfBlock);
     // The second operand of CTR_INIT is the location following the end of the loop.
     //   Must put in as a URX_RELOC_OPRND so that the value will be adjusted if the
     //   compilation of something later on causes the code to grow and the target
     //   position to move.
     int32_t loopEnd = fRXPat->fCompiledPat->size();
     op = URX_BUILD(URX_RELOC_OPRND, loopEnd);
     fRXPat->fCompiledPat->setElementAt(op, topOfBlock+1);
     // Followed by the min and max counts.
     fRXPat->fCompiledPat->setElementAt(fIntervalLow, topOfBlock+2);
     fRXPat->fCompiledPat->setElementAt(fIntervalUpper, topOfBlock+3);
     // Apend the CTR_LOOP op.  The operand is the location of the CTR_INIT op.
     //   Goes at end of the block being looped over, so just append to the code so far.
     op = URX_BUILD(LoopOp, topOfBlock);
     fRXPat->fCompiledPat->addElement(op, *fStatus);
     if ((fIntervalLow & 0xff000000) != 0 ||
         (fIntervalUpper > 0 && (fIntervalUpper & 0xff000000) != 0)) {
             error(U_REGEX_NUMBER_TOO_BIG);
         }
     if (fIntervalLow > fIntervalUpper && fIntervalUpper != -1) {
         error(U_REGEX_MAX_LT_MIN);
     }
 }
 UBool RegexCompile::compileInlineInterval() {
     if (fIntervalUpper > 10 || fIntervalUpper < fIntervalLow) {
         // Too big to inline.  Fail, which will cause looping code to be generated.
         //   (Upper < Lower picks up unbounded upper and errors, both.)
         return FALSE;
     }
     int32_t   topOfBlock = blockTopLoc(FALSE);
     if (fIntervalUpper == 0) {
         // Pathological case.  Attempt no matches, as if the block doesn't exist.
         fRXPat->fCompiledPat->setSize(topOfBlock);
         return TRUE;
     }
     if (topOfBlock != fRXPat->fCompiledPat->size()-1 && fIntervalUpper != 1) {
         // The thing being repeated is not a single op, but some
         //   more complex block.  Do it as a loop, not inlines.
         //   Note that things "repeated" a max of once are handled as inline, because
         //     the one copy of the code already generated is just fine.
         return FALSE;
     }
     // Pick up the opcode that is to be repeated
     //
     int32_t op = (int32_t)fRXPat->fCompiledPat->elementAti(topOfBlock);
     // Compute the pattern location where the inline sequence
     //   will end, and set up the state save op that will be needed.
     //
     int32_t endOfSequenceLoc = fRXPat->fCompiledPat->size()-1
                                 + fIntervalUpper + (fIntervalUpper-fIntervalLow);
     int32_t saveOp = URX_BUILD(URX_STATE_SAVE, endOfSequenceLoc);
     if (fIntervalLow == 0) {
         insertOp(topOfBlock);
         fRXPat->fCompiledPat->setElementAt(saveOp, topOfBlock);
     }
     //  Loop, emitting the op for the thing being repeated each time.
     //    Loop starts at 1 because one instance of the op already exists in the pattern,
     //    it was put there when it was originally encountered.
     int32_t i;
     for (i=1; i<fIntervalUpper; i++ ) {
         if (i == fIntervalLow) {
             fRXPat->fCompiledPat->addElement(saveOp, *fStatus);
         }
         if (i > fIntervalLow) {
             fRXPat->fCompiledPat->addElement(saveOp, *fStatus);
         }
         fRXPat->fCompiledPat->addElement(op, *fStatus);
     }
     return TRUE;
 }
 //------------------------------------------------------------------------------
 //
 //   matchStartType    Determine how a match can start.
 //                     Used to optimize find() operations.
 //
 //                     Operation is very similar to minMatchLength().  Walk the compiled
 //                     pattern, keeping an on-going minimum-match-length.  For any
 //                     op where the min match coming in is zero, add that ops possible
 //                     starting matches to the possible starts for the overall pattern.
 //
 //------------------------------------------------------------------------------
 void   RegexCompile::matchStartType() {
     if (U_FAILURE(*fStatus)) {
         return;
     }
     int32_t    loc;                    // Location in the pattern of the current op being processed.
     int32_t    op;                     // The op being processed
     int32_t    opType;                 // The opcode type of the op
     int32_t    currentLen = 0;         // Minimum length of a match to this point (loc) in the pattern
     int32_t    numInitialStrings = 0;  // Number of strings encountered that could match at start.
     UBool      atStart = TRUE;         // True if no part of the pattern yet encountered
                                        //   could have advanced the position in a match.
                                        //   (Maximum match length so far == 0)
     // forwardedLength is a vector holding minimum-match-length values that
     //   are propagated forward in the pattern by JMP or STATE_SAVE operations.
     //   It must be one longer than the pattern being checked because some  ops
     //   will jmp to a end-of-block+1 location from within a block, and we must
     //   count those when checking the block.
     int32_t end = fRXPat->fCompiledPat->size();
     UVector32  forwardedLength(end+1, *fStatus);
     forwardedLength.setSize(end+1);
     for (loc=3; loc<end; loc++) {
         forwardedLength.setElementAt(INT32_MAX, loc);
     }
     for (loc = 3; loc<end; loc++) {
         op = (int32_t)fRXPat->fCompiledPat->elementAti(loc);
         opType = URX_TYPE(op);
         // The loop is advancing linearly through the pattern.
         // If the op we are now at was the destination of a branch in the pattern,
         // and that path has a shorter minimum length than the current accumulated value,
         // replace the current accumulated value.
         if (forwardedLength.elementAti(loc) < currentLen) {
             currentLen = forwardedLength.elementAti(loc);
             U_ASSERT(currentLen>=0 && currentLen < INT32_MAX);
         }
         switch (opType) {
             // Ops that don't change the total length matched
         case URX_RESERVED_OP:
         case URX_END:
         case URX_FAIL:
         case URX_STRING_LEN:
         case URX_NOP:
         case URX_START_CAPTURE:
         case URX_END_CAPTURE:
         case URX_BACKSLASH_B:
         case URX_BACKSLASH_BU:
         case URX_BACKSLASH_G:
         case URX_BACKSLASH_Z:
         case URX_DOLLAR:
         case URX_DOLLAR_M:
         case URX_DOLLAR_D:
         case URX_DOLLAR_MD:
         case URX_RELOC_OPRND:
         case URX_STO_INP_LOC:
         case URX_BACKREF:         // BackRef.  Must assume that it might be a zero length match
         case URX_BACKREF_I:
         case URX_STO_SP:          // Setup for atomic or possessive blocks.  Doesn't change what can match.
         case URX_LD_SP:
             break;
         case URX_CARET:
             if (atStart) {
                 fRXPat->fStartType = START_START;
             }
             break;
         case URX_CARET_M:
         case URX_CARET_M_UNIX:
             if (atStart) {
                 fRXPat->fStartType = START_LINE;
             }
             break;
         case URX_ONECHAR:
             if (currentLen == 0) {
                 // This character could appear at the start of a match.
                 //   Add it to the set of possible starting characters.
                 fRXPat->fInitialChars->add(URX_VAL(op));
                 numInitialStrings += 2;
             }
             currentLen++;
             atStart = FALSE;
             break;
         case URX_SETREF:
             if (currentLen == 0) {
                 int32_t  sn = URX_VAL(op);
                 U_ASSERT(sn > 0 && sn < fRXPat->fSets->size());
                 const UnicodeSet *s = (UnicodeSet *)fRXPat->fSets->elementAt(sn);
                 fRXPat->fInitialChars->addAll(*s);
                 numInitialStrings += 2;
             }
             currentLen++;
             atStart = FALSE;
             break;
         case URX_LOOP_SR_I:
             // [Set]*, like a SETREF, above, in what it can match,
             //  but may not match at all, so currentLen is not incremented.
             if (currentLen == 0) {
                 int32_t  sn = URX_VAL(op);
                 U_ASSERT(sn > 0 && sn < fRXPat->fSets->size());
                 const UnicodeSet *s = (UnicodeSet *)fRXPat->fSets->elementAt(sn);
                 fRXPat->fInitialChars->addAll(*s);
                 numInitialStrings += 2;
             }
             atStart = FALSE;
             break;
         case URX_LOOP_DOT_I:
             if (currentLen == 0) {
                 // .* at the start of a pattern.
                 //    Any character can begin the match.
                 fRXPat->fInitialChars->clear();
                 fRXPat->fInitialChars->complement();
                 numInitialStrings += 2;
             }
             atStart = FALSE;
             break;
         case URX_STATIC_SETREF:
             if (currentLen == 0) {
                 int32_t  sn = URX_VAL(op);
                 U_ASSERT(sn>0 && sn<URX_LAST_SET);
                 const UnicodeSet *s = fRXPat->fStaticSets[sn];
                 fRXPat->fInitialChars->addAll(*s);
                 numInitialStrings += 2;
             }
             currentLen++;
             atStart = FALSE;
             break;
         case URX_STAT_SETREF_N:
             if (currentLen == 0) {
                 int32_t  sn = URX_VAL(op);
                 const UnicodeSet *s = fRXPat->fStaticSets[sn];
                 UnicodeSet sc(*s);
                 sc.complement();
                 fRXPat->fInitialChars->addAll(sc);
                 numInitialStrings += 2;
             }
             currentLen++;
             atStart = FALSE;
             break;
         case URX_BACKSLASH_D:
             // Digit Char
              if (currentLen == 0) {
                  UnicodeSet s;
                  s.applyIntPropertyValue(UCHAR_GENERAL_CATEGORY_MASK, U_GC_ND_MASK, *fStatus);
                  if (URX_VAL(op) != 0) {
                      s.complement();
                  }
                  fRXPat->fInitialChars->addAll(s);
                  numInitialStrings += 2;
             }
             currentLen++;
             atStart = FALSE;
             break;
         case URX_ONECHAR_I:
             // Case Insensitive Single Character.
             if (currentLen == 0) {
                 UChar32  c = URX_VAL(op);
                 if (u_hasBinaryProperty(c, UCHAR_CASE_SENSITIVE)) {
                     // Disable optimizations on first char of match.
                     // TODO: Compute the set of chars that case fold to this char, or to
                     //       a string that begins with this char.
                     //       For simple case folding, this code worked:
                     //   UnicodeSet s(c, c);
                     //   s.closeOver(USET_CASE_INSENSITIVE);
                     //   fRXPat->fInitialChars->addAll(s);
                     fRXPat->fInitialChars->clear();
                     fRXPat->fInitialChars->complement();
                 } else {
                     // Char has no case variants.  Just add it as-is to the
                     //   set of possible starting chars.
                     fRXPat->fInitialChars->add(c);
                 }
                 numInitialStrings += 2;
             }
             currentLen++;
             atStart = FALSE;
             break;
         case URX_BACKSLASH_X:   // Grahpeme Cluster.  Minimum is 1, max unbounded.
         case URX_DOTANY_ALL:    // . matches one or two.
         case URX_DOTANY:
         case URX_DOTANY_UNIX:
             if (currentLen == 0) {
                 // These constructs are all bad news when they appear at the start
                 //   of a match.  Any character can begin the match.
                 fRXPat->fInitialChars->clear();
                 fRXPat->fInitialChars->complement();
                 numInitialStrings += 2;
             }
             currentLen++;
             atStart = FALSE;
             break;
         case URX_JMPX:
             loc++;             // Except for extra operand on URX_JMPX, same as URX_JMP.
         case URX_JMP:
             {
                 int32_t  jmpDest = URX_VAL(op);
                 if (jmpDest < loc) {
                     // Loop of some kind.  Can safely ignore, the worst that will happen
                     //  is that we understate the true minimum length
                     currentLen = forwardedLength.elementAti(loc+1);
                 } else {
                     // Forward jump.  Propagate the current min length to the target loc of the jump.
                     U_ASSERT(jmpDest <= end+1);
                     if (forwardedLength.elementAti(jmpDest) > currentLen) {
                         forwardedLength.setElementAt(currentLen, jmpDest);
                     }
                 }
             }
             atStart = FALSE;
             break;
         case URX_JMP_SAV:
         case URX_JMP_SAV_X:
             // Combo of state save to the next loc, + jmp backwards.
             //   Net effect on min. length computation is nothing.
             atStart = FALSE;
             break;
         case URX_BACKTRACK:
             // Fails are kind of like a branch, except that the min length was
             //   propagated already, by the state save.
             currentLen = forwardedLength.elementAti(loc+1);
             atStart = FALSE;
             break;
         case URX_STATE_SAVE:
             {
                 // State Save, for forward jumps, propagate the current minimum.
                 //             of the state save.
                 int32_t  jmpDest = URX_VAL(op);
                 if (jmpDest > loc) {
                     if (currentLen < forwardedLength.elementAti(jmpDest)) {
                         forwardedLength.setElementAt(currentLen, jmpDest);
                     }
                 }
             }
             atStart = FALSE;
             break;
         case URX_STRING:
             {
                 loc++;
                 int32_t stringLenOp = (int32_t)fRXPat->fCompiledPat->elementAti(loc);
                 int32_t stringLen   = URX_VAL(stringLenOp);
                 U_ASSERT(URX_TYPE(stringLenOp) == URX_STRING_LEN);
                 U_ASSERT(stringLenOp >= 2);
                 if (currentLen == 0) {
                     // Add the starting character of this string to the set of possible starting
                     //   characters for this pattern.
                     int32_t stringStartIdx = URX_VAL(op);
                     UChar32  c = fRXPat->fLiteralText.char32At(stringStartIdx);
                     fRXPat->fInitialChars->add(c);
                     // Remember this string.  After the entire pattern has been checked,
                     //  if nothing else is identified that can start a match, we'll use it.
                     numInitialStrings++;
                     fRXPat->fInitialStringIdx = stringStartIdx;
                     fRXPat->fInitialStringLen = stringLen;
                 }
                 currentLen += stringLen;
                 atStart = FALSE;
             }
             break;
         case URX_STRING_I:
             {
                 // Case-insensitive string.  Unlike exact-match strings, we won't
                 //   attempt a string search for possible match positions.  But we
                 //   do update the set of possible starting characters.
                 loc++;
                 int32_t stringLenOp = (int32_t)fRXPat->fCompiledPat->elementAti(loc);
                 int32_t stringLen   = URX_VAL(stringLenOp);
                 U_ASSERT(URX_TYPE(stringLenOp) == URX_STRING_LEN);
                 U_ASSERT(stringLenOp >= 2);
                 if (currentLen == 0) {
                     // Add the starting character of this string to the set of possible starting
                     //   characters for this pattern.
                     int32_t stringStartIdx = URX_VAL(op);
                     UChar32  c = fRXPat->fLiteralText.char32At(stringStartIdx);
                     UnicodeSet s(c, c);
                     // TODO:  compute correct set of starting chars for full case folding.
                     //        For the moment, say any char can start.
                     // s.closeOver(USET_CASE_INSENSITIVE);
                     s.clear();
                     s.complement();
                     fRXPat->fInitialChars->addAll(s);
                     numInitialStrings += 2;  // Matching on an initial string not possible.
                 }
                 currentLen += stringLen;
                 atStart = FALSE;
             }
             break;
         case URX_CTR_INIT:
         case URX_CTR_INIT_NG:
             {
                 // Loop Init Ops.  These don't change the min length, but they are 4 word ops
                 //   so location must be updated accordingly.
                 // Loop Init Ops.
                 //   If the min loop count == 0
                 //      move loc forwards to the end of the loop, skipping over the body.
                 //   If the min count is > 0,
                 //      continue normal processing of the body of the loop.
                 int32_t loopEndLoc   = (int32_t)fRXPat->fCompiledPat->elementAti(loc+1);
                         loopEndLoc   = URX_VAL(loopEndLoc);
                 int32_t minLoopCount = (int32_t)fRXPat->fCompiledPat->elementAti(loc+2);
                 if (minLoopCount == 0) {
                     // Min Loop Count of 0, treat like a forward branch and
                     //   move the current minimum length up to the target
                     //   (end of loop) location.
                     U_ASSERT(loopEndLoc <= end+1);
                     if (forwardedLength.elementAti(loopEndLoc) > currentLen) {
                         forwardedLength.setElementAt(currentLen, loopEndLoc);
                     }
                 }
                 loc+=3;  // Skips over operands of CTR_INIT
             }
             atStart = FALSE;
             break;
         case URX_CTR_LOOP:
         case URX_CTR_LOOP_NG:
             // Loop ops.
             //  The jump is conditional, backwards only.
             atStart = FALSE;
             break;
         case URX_LOOP_C:
             // More loop ops.  These state-save to themselves.
             //   don't change the minimum match
             atStart = FALSE;
             break;
         case URX_LA_START:
         case URX_LB_START:
             {
                 // Look-around.  Scan forward until the matching look-ahead end,
                 //   without processing the look-around block.  This is overly pessimistic.
                 // Keep track of the nesting depth of look-around blocks.  Boilerplate code for
                 //   lookahead contains two LA_END instructions, so count goes up by two
                 //   for each LA_START.
                 int32_t  depth = (opType == URX_LA_START? 2: 1);
                 for (;;) {
                     loc++;
                     op = (int32_t)fRXPat->fCompiledPat->elementAti(loc);
                     if (URX_TYPE(op) == URX_LA_START) {
                         depth+=2;
                     }
                     if (URX_TYPE(op) == URX_LB_START) {
                         depth++;
                     }
                     if (URX_TYPE(op) == URX_LA_END || URX_TYPE(op)==URX_LBN_END) {
                         depth--;
                         if (depth == 0) {
                             break;
                         }
                     }
                     if (URX_TYPE(op) == URX_STATE_SAVE) {
                         // Need this because neg lookahead blocks will FAIL to outside
                         //   of the block.
                         int32_t  jmpDest = URX_VAL(op);
                         if (jmpDest > loc) {
                             if (currentLen < forwardedLength.elementAti(jmpDest)) {
                                 forwardedLength.setElementAt(currentLen, jmpDest);
                             }
                         }
                     }
                     U_ASSERT(loc <= end);
                 }
             }
             break;
         case URX_LA_END:
         case URX_LB_CONT:
         case URX_LB_END:
         case URX_LBN_CONT:
         case URX_LBN_END:
             U_ASSERT(FALSE);     // Shouldn't get here.  These ops should be
                                  //  consumed by the scan in URX_LA_START and LB_START
             break;
         default:
             U_ASSERT(FALSE);
             }
         }
     // We have finished walking through the ops.  Check whether some forward jump
     //   propagated a shorter length to location end+1.
     if (forwardedLength.elementAti(end+1) < currentLen) {
         currentLen = forwardedLength.elementAti(end+1);
     }
     fRXPat->fInitialChars8->init(fRXPat->fInitialChars);
     // Sort out what we should check for when looking for candidate match start positions.
     // In order of preference,
     //     1.   Start of input text buffer.
     //     2.   A literal string.
     //     3.   Start of line in multi-line mode.
     //     4.   A single literal character.
     //     5.   A character from a set of characters.
     //
     if (fRXPat->fStartType == START_START) {
         // Match only at the start of an input text string.
         //    start type is already set.  We're done.
     } else if (numInitialStrings == 1 && fRXPat->fMinMatchLen > 0) {
         // Match beginning only with a literal string.
         UChar32  c = fRXPat->fLiteralText.char32At(fRXPat->fInitialStringIdx);
         U_ASSERT(fRXPat->fInitialChars->contains(c));
         fRXPat->fStartType   = START_STRING;
         fRXPat->fInitialChar = c;
     } else if (fRXPat->fStartType == START_LINE) {
         // Match at start of line in Multi-Line mode.
         // Nothing to do here; everything is already set.
     } else if (fRXPat->fMinMatchLen == 0) {
         // Zero length match possible.  We could start anywhere.
         fRXPat->fStartType = START_NO_INFO;
     } else if (fRXPat->fInitialChars->size() == 1) {
         // All matches begin with the same char.
         fRXPat->fStartType   = START_CHAR;
         fRXPat->fInitialChar = fRXPat->fInitialChars->charAt(0);
         U_ASSERT(fRXPat->fInitialChar != (UChar32)-1);
     } else if (fRXPat->fInitialChars->contains((UChar32)0, (UChar32)0x10ffff) == FALSE &&
         fRXPat->fMinMatchLen > 0) {
         // Matches start with a set of character smaller than the set of all chars.
         fRXPat->fStartType = START_SET;
     } else {
         // Matches can start with anything
         fRXPat->fStartType = START_NO_INFO;
     }
     return;
 }
 //------------------------------------------------------------------------------
 //
 //   minMatchLength    Calculate the length of the shortest string that could
 //                     match the specified pattern.
 //                     Length is in 16 bit code units, not code points.
 //
 //                     The calculated length may not be exact.  The returned
 //                     value may be shorter than the actual minimum; it must
 //                     never be longer.
 //
 //                     start and end are the range of p-code operations to be
 //                     examined.  The endpoints are included in the range.
 //
 //------------------------------------------------------------------------------
 int32_t   RegexCompile::minMatchLength(int32_t start, int32_t end) {
     if (U_FAILURE(*fStatus)) {
         return 0;
     }
     U_ASSERT(start <= end);
     U_ASSERT(end < fRXPat->fCompiledPat->size());
     int32_t    loc;
     int32_t    op;
     int32_t    opType;
     int32_t    currentLen = 0;
     // forwardedLength is a vector holding minimum-match-length values that
     //   are propagated forward in the pattern by JMP or STATE_SAVE operations.
     //   It must be one longer than the pattern being checked because some  ops
     //   will jmp to a end-of-block+1 location from within a block, and we must
     //   count those when checking the block.
     UVector32  forwardedLength(end+2, *fStatus);
     forwardedLength.setSize(end+2);
     for (loc=start; loc<=end+1; loc++) {
         forwardedLength.setElementAt(INT32_MAX, loc);
     }
     for (loc = start; loc<=end; loc++) {
         op = (int32_t)fRXPat->fCompiledPat->elementAti(loc);
         opType = URX_TYPE(op);
         // The loop is advancing linearly through the pattern.
         // If the op we are now at was the destination of a branch in the pattern,
         // and that path has a shorter minimum length than the current accumulated value,
         // replace the current accumulated value.
         // U_ASSERT(currentLen>=0 && currentLen < INT32_MAX);  // MinLength == INT32_MAX for some
                                                                //   no-match-possible cases.
         if (forwardedLength.elementAti(loc) < currentLen) {
             currentLen = forwardedLength.elementAti(loc);
             U_ASSERT(currentLen>=0 && currentLen < INT32_MAX);
         }
         switch (opType) {
             // Ops that don't change the total length matched
         case URX_RESERVED_OP:
         case URX_END:
         case URX_STRING_LEN:
         case URX_NOP:
         case URX_START_CAPTURE:
         case URX_END_CAPTURE:
         case URX_BACKSLASH_B:
         case URX_BACKSLASH_BU:
         case URX_BACKSLASH_G:
         case URX_BACKSLASH_Z:
         case URX_CARET:
         case URX_DOLLAR:
         case URX_DOLLAR_M:
         case URX_DOLLAR_D:
         case URX_DOLLAR_MD:
         case URX_RELOC_OPRND:
         case URX_STO_INP_LOC:
         case URX_CARET_M:
         case URX_CARET_M_UNIX:
         case URX_BACKREF:         // BackRef.  Must assume that it might be a zero length match
         case URX_BACKREF_I:
         case URX_STO_SP:          // Setup for atomic or possessive blocks.  Doesn't change what can match.
         case URX_LD_SP:
         case URX_JMP_SAV:
         case URX_JMP_SAV_X:
             break;
             // Ops that match a minimum of one character (one or two 16 bit code units.)
             //
         case URX_ONECHAR:
         case URX_STATIC_SETREF:
         case URX_STAT_SETREF_N:
         case URX_SETREF:
         case URX_BACKSLASH_D:
         case URX_ONECHAR_I:
         case URX_BACKSLASH_X:   // Grahpeme Cluster.  Minimum is 1, max unbounded.
         case URX_DOTANY_ALL:    // . matches one or two.
         case URX_DOTANY:
         case URX_DOTANY_UNIX:
             currentLen++;
             break;
         case URX_JMPX:
             loc++;              // URX_JMPX has an extra operand, ignored here,
                                 //   otherwise processed identically to URX_JMP.
         case URX_JMP:
             {
                 int32_t  jmpDest = URX_VAL(op);
                 if (jmpDest < loc) {
                     // Loop of some kind.  Can safely ignore, the worst that will happen
                     //  is that we understate the true minimum length
                     currentLen = forwardedLength.elementAti(loc+1);
                 } else {
                     // Forward jump.  Propagate the current min length to the target loc of the jump.
                     U_ASSERT(jmpDest <= end+1);
                     if (forwardedLength.elementAti(jmpDest) > currentLen) {
                         forwardedLength.setElementAt(currentLen, jmpDest);
                     }
                 }
             }
             break;
         case URX_BACKTRACK:
             {
                 // Back-tracks are kind of like a branch, except that the min length was
                 //   propagated already, by the state save.
                 currentLen = forwardedLength.elementAti(loc+1);
             }
             break;
         case URX_STATE_SAVE:
             {
                 // State Save, for forward jumps, propagate the current minimum.
                 //             of the state save.
                 int32_t  jmpDest = URX_VAL(op);
                 if (jmpDest > loc) {
                     if (currentLen < forwardedLength.elementAti(jmpDest)) {
                         forwardedLength.setElementAt(currentLen, jmpDest);
                     }
                 }
             }
             break;
         case URX_STRING:
             {
                 loc++;
                 int32_t stringLenOp = (int32_t)fRXPat->fCompiledPat->elementAti(loc);
                 currentLen += URX_VAL(stringLenOp);
             }
             break;
         case URX_STRING_I:
             {
                 loc++;
                 // TODO: with full case folding, matching input text may be shorter than
                 //       the string we have here.  More smarts could put some bounds on it.
                 //       Assume a min length of one for now.  A min length of zero causes
                 //        optimization failures for a pattern like "string"+
                 // currentLen += URX_VAL(stringLenOp);
                 currentLen += 1;
             }
             break;
         case URX_CTR_INIT:
         case URX_CTR_INIT_NG:
             {
                 // Loop Init Ops.
                 //   If the min loop count == 0
                 //      move loc forwards to the end of the loop, skipping over the body.
                 //   If the min count is > 0,
                 //      continue normal processing of the body of the loop.
                 int32_t loopEndLoc   = (int32_t)fRXPat->fCompiledPat->elementAti(loc+1);
                         loopEndLoc   = URX_VAL(loopEndLoc);
                 int32_t minLoopCount = (int32_t)fRXPat->fCompiledPat->elementAti(loc+2);
                 if (minLoopCount == 0) {
                     loc = loopEndLoc;
                 } else {
                     loc+=3;  // Skips over operands of CTR_INIT
                 }
             }
             break;
         case URX_CTR_LOOP:
         case URX_CTR_LOOP_NG:
             // Loop ops.
             //  The jump is conditional, backwards only.
             break;
         case URX_LOOP_SR_I:
         case URX_LOOP_DOT_I:
         case URX_LOOP_C:
             // More loop ops.  These state-save to themselves.
             //   don't change the minimum match - could match nothing at all.
             break;
         case URX_LA_START:
         case URX_LB_START:
             {
                 // Look-around.  Scan forward until the matching look-ahead end,
                 //   without processing the look-around block.  This is overly pessimistic for look-ahead,
                 //   it assumes that the look-ahead match might be zero-length.
                 //   TODO:  Positive lookahead could recursively do the block, then continue
                 //          with the longer of the block or the value coming in.  Ticket 6060
                 int32_t  depth = (opType == URX_LA_START? 2: 1);;
                 for (;;) {
                     loc++;
                     op = (int32_t)fRXPat->fCompiledPat->elementAti(loc);
                     if (URX_TYPE(op) == URX_LA_START) {
                         // The boilerplate for look-ahead includes two LA_END insturctions,
                         //    Depth will be decremented by each one when it is seen.
                         depth += 2;
                     }
                     if (URX_TYPE(op) == URX_LB_START) {
                         depth++;
                     }
                     if (URX_TYPE(op) == URX_LA_END) {
                         depth--;
                         if (depth == 0) {
                             break;
                         }
                     }
                     if (URX_TYPE(op)==URX_LBN_END) {
                         depth--;
                         if (depth == 0) {
                             break;
                         }
                     }
                     if (URX_TYPE(op) == URX_STATE_SAVE) {
                         // Need this because neg lookahead blocks will FAIL to outside
                         //   of the block.
                         int32_t  jmpDest = URX_VAL(op);
                         if (jmpDest > loc) {
                             if (currentLen < forwardedLength.elementAti(jmpDest)) {
                                 forwardedLength.setElementAt(currentLen, jmpDest);
                             }
                         }
                     }
                     U_ASSERT(loc <= end);
                 }
             }
             break;
         case URX_LA_END:
         case URX_LB_CONT:
         case URX_LB_END:
         case URX_LBN_CONT:
         case URX_LBN_END:
             // Only come here if the matching URX_LA_START or URX_LB_START was not in the
             //   range being sized, which happens when measuring size of look-behind blocks.
             break;
         default:
             U_ASSERT(FALSE);
             }
         }
     // We have finished walking through the ops.  Check whether some forward jump
     //   propagated a shorter length to location end+1.
     if (forwardedLength.elementAti(end+1) < currentLen) {
         currentLen = forwardedLength.elementAti(end+1);
         U_ASSERT(currentLen>=0 && currentLen < INT32_MAX);
     }
     return currentLen;
 }
 // Increment with overflow check.
 // val and delta will both be positive.
 static int32_t safeIncrement(int32_t val, int32_t delta) {
     if (INT32_MAX - val > delta) {
         return val + delta;
     } else {
         return INT32_MAX;
     }
 }
 //------------------------------------------------------------------------------
 //
 //   maxMatchLength    Calculate the length of the longest string that could
 //                     match the specified pattern.
 //                     Length is in 16 bit code units, not code points.
 //
 //                     The calculated length may not be exact.  The returned
 //                     value may be longer than the actual maximum; it must
 //                     never be shorter.
 //
 //------------------------------------------------------------------------------
 int32_t   RegexCompile::maxMatchLength(int32_t start, int32_t end) {
     if (U_FAILURE(*fStatus)) {
         return 0;
     }
     U_ASSERT(start <= end);
     U_ASSERT(end < fRXPat->fCompiledPat->size());
     int32_t    loc;
     int32_t    op;
     int32_t    opType;
     int32_t    currentLen = 0;
     UVector32  forwardedLength(end+1, *fStatus);
     forwardedLength.setSize(end+1);
     for (loc=start; loc<=end; loc++) {
         forwardedLength.setElementAt(0, loc);
     }
     for (loc = start; loc<=end; loc++) {
         op = (int32_t)fRXPat->fCompiledPat->elementAti(loc);
         opType = URX_TYPE(op);
         // The loop is advancing linearly through the pattern.
         // If the op we are now at was the destination of a branch in the pattern,
         // and that path has a longer maximum length than the current accumulated value,
         // replace the current accumulated value.
         if (forwardedLength.elementAti(loc) > currentLen) {
             currentLen = forwardedLength.elementAti(loc);
         }
         switch (opType) {
             // Ops that don't change the total length matched
         case URX_RESERVED_OP:
         case URX_END:
         case URX_STRING_LEN:
         case URX_NOP:
         case URX_START_CAPTURE:
         case URX_END_CAPTURE:
         case URX_BACKSLASH_B:
         case URX_BACKSLASH_BU:
         case URX_BACKSLASH_G:
         case URX_BACKSLASH_Z:
         case URX_CARET:
         case URX_DOLLAR:
         case URX_DOLLAR_M:
         case URX_DOLLAR_D:
         case URX_DOLLAR_MD:
         case URX_RELOC_OPRND:
         case URX_STO_INP_LOC:
         case URX_CARET_M:
         case URX_CARET_M_UNIX:
         case URX_STO_SP:          // Setup for atomic or possessive blocks.  Doesn't change what can match.
         case URX_LD_SP:
         case URX_LB_END:
         case URX_LB_CONT:
         case URX_LBN_CONT:
         case URX_LBN_END:
             break;
             // Ops that increase that cause an unbounded increase in the length
             //   of a matched string, or that increase it a hard to characterize way.
             //   Call the max length unbounded, and stop further checking.
         case URX_BACKREF:         // BackRef.  Must assume that it might be a zero length match
         case URX_BACKREF_I:
         case URX_BACKSLASH_X:   // Grahpeme Cluster.  Minimum is 1, max unbounded.
             currentLen = INT32_MAX;
             break;
             // Ops that match a max of one character (possibly two 16 bit code units.)
             //
         case URX_STATIC_SETREF:
         case URX_STAT_SETREF_N:
         case URX_SETREF:
         case URX_BACKSLASH_D:
         case URX_ONECHAR_I:
         case URX_DOTANY_ALL:
         case URX_DOTANY:
         case URX_DOTANY_UNIX:
             currentLen = safeIncrement(currentLen, 2);
             break;
             // Single literal character.  Increase current max length by one or two,
             //       depending on whether the char is in the supplementary range.
         case URX_ONECHAR:
             currentLen = safeIncrement(currentLen, 1);
             if (URX_VAL(op) > 0x10000) {
                 currentLen = safeIncrement(currentLen, 1);
             }
             break;
             // Jumps.
             //
         case URX_JMP:
         case URX_JMPX:
         case URX_JMP_SAV:
         case URX_JMP_SAV_X:
             {
                 int32_t  jmpDest = URX_VAL(op);
                 if (jmpDest < loc) {
                     // Loop of some kind.  Max match length is unbounded.
                     currentLen = INT32_MAX;
                 } else {
                     // Forward jump.  Propagate the current min length to the target loc of the jump.
                     if (forwardedLength.elementAti(jmpDest) < currentLen) {
                         forwardedLength.setElementAt(currentLen, jmpDest);
                     }
                     currentLen = 0;
                 }
             }
             break;
         case URX_BACKTRACK:
             // back-tracks are kind of like a branch, except that the max length was
             //   propagated already, by the state save.
             currentLen = forwardedLength.elementAti(loc+1);
             break;
         case URX_STATE_SAVE:
             {
                 // State Save, for forward jumps, propagate the current minimum.
                 //               of the state save.
                 //             For backwards jumps, they create a loop, maximum
                 //               match length is unbounded.
                 int32_t  jmpDest = URX_VAL(op);
                 if (jmpDest > loc) {
                     if (currentLen > forwardedLength.elementAti(jmpDest)) {
                         forwardedLength.setElementAt(currentLen, jmpDest);
                     }
                 } else {
                     currentLen = INT32_MAX;
                 }
             }
             break;
         case URX_STRING:
             {
                 loc++;
                 int32_t stringLenOp = (int32_t)fRXPat->fCompiledPat->elementAti(loc);
                 currentLen = safeIncrement(currentLen, URX_VAL(stringLenOp));
                 break;
             }
         case URX_STRING_I:
             // TODO:  This code assumes that any user string that matches will be no longer
             //        than our compiled string, with case insensitive matching.
             //        Our compiled string has been case-folded already.
             //
             //        Any matching user string will have no more code points than our
             //        compiled (folded) string.  Folding may add code points, but
             //        not remove them.
             //
             //        There is a potential problem if a supplemental code point
             //        case-folds to a BMP code point.  In this case our compiled string
             //        could be shorter (in code units) than a matching user string.
             //
             //        At this time (Unicode 6.1) there are no such characters, and this case
             //        is not being handled.  A test, intltest regex/Bug9283, will fail if
             //        any problematic characters are added to Unicode.
             //
             //        If this happens, we can make a set of the BMP chars that the
             //        troublesome supplementals fold to, scan our string, and bump the
             //        currentLen one extra for each that is found.
             //
             {
                 loc++;
                 int32_t stringLenOp = (int32_t)fRXPat->fCompiledPat->elementAti(loc);
                 currentLen = safeIncrement(currentLen, URX_VAL(stringLenOp));
             }
             break;
         case URX_CTR_INIT:
         case URX_CTR_INIT_NG:
             // For Loops, recursively call this function on the pattern for the loop body,
             //   then multiply the result by the maximum loop count.
             {
                 int32_t  loopEndLoc = URX_VAL(fRXPat->fCompiledPat->elementAti(loc+1));
                 if (loopEndLoc == loc+4) {
                     // Loop has an empty body. No affect on max match length.
                     // Continue processing with code after the loop end.
                     loc = loopEndLoc;
                     break;
                 }
                 int32_t maxLoopCount = fRXPat->fCompiledPat->elementAti(loc+3);
                 if (maxLoopCount == -1) {
                     // Unbounded Loop. No upper bound on match length.
                     currentLen = INT32_MAX;
                     break;
                 }
                 U_ASSERT(loopEndLoc >= loc+4);
                 int32_t  blockLen = maxMatchLength(loc+4, loopEndLoc-1);  // Recursive call.
                 if (blockLen == INT32_MAX) {
                     currentLen = blockLen;
                     break;
                 }
                 currentLen += blockLen * maxLoopCount;
                 loc = loopEndLoc;
                 break;
             }
         case URX_CTR_LOOP:
         case URX_CTR_LOOP_NG:
             // These opcodes will be skipped over by code for URX_CRT_INIT.
             // We shouldn't encounter them here.
             U_ASSERT(FALSE);
             break;
         case URX_LOOP_SR_I:
         case URX_LOOP_DOT_I:
         case URX_LOOP_C:
             // For anything to do with loops, make the match length unbounded.
             currentLen = INT32_MAX;
             break;
         case URX_LA_START:
         case URX_LA_END:
             // Look-ahead.  Just ignore, treat the look-ahead block as if
             // it were normal pattern.  Gives a too-long match length,
             //  but good enough for now.
             break;
             // End of look-ahead ops should always be consumed by the processing at
             //  the URX_LA_START op.
             // U_ASSERT(FALSE);
             // break;
         case URX_LB_START:
             {
                 // Look-behind.  Scan forward until the matching look-around end,
                 //   without processing the look-behind block.
                 int32_t  depth = 0;
                 for (;;) {
                     loc++;
                     op = (int32_t)fRXPat->fCompiledPat->elementAti(loc);
                     if (URX_TYPE(op) == URX_LA_START || URX_TYPE(op) == URX_LB_START) {
                         depth++;
                     }
                     if (URX_TYPE(op) == URX_LA_END || URX_TYPE(op)==URX_LBN_END) {
                         if (depth == 0) {
                             break;
                         }
                         depth--;
                     }
                     U_ASSERT(loc < end);
                 }
             }
             break;
         default:
             U_ASSERT(FALSE);
         }
         if (currentLen == INT32_MAX) {
             //  The maximum length is unbounded.
             //  Stop further processing of the pattern.
             break;
         }
     }
     return currentLen;
 }
 //------------------------------------------------------------------------------
 //
 //   stripNOPs    Remove any NOP operations from the compiled pattern code.
 //                Extra NOPs are inserted for some constructs during the initial
 //                code generation to provide locations that may be patched later.
 //                Many end up unneeded, and are removed by this function.
 //
 //                In order to minimize the number of passes through the pattern,
 //                back-reference fixup is also performed here (adjusting
 //                back-reference operands to point to the correct frame offsets).
 //
 //------------------------------------------------------------------------------
 void RegexCompile::stripNOPs() {
     if (U_FAILURE(*fStatus)) {
         return;
     }
     int32_t    end = fRXPat->fCompiledPat->size();
     UVector32  deltas(end, *fStatus);
     // Make a first pass over the code, computing the amount that things
     //   will be offset at each location in the original code.
     int32_t   loc;
     int32_t   d = 0;
     for (loc=0; loc<end; loc++) {
         deltas.addElement(d, *fStatus);
         int32_t op = (int32_t)fRXPat->fCompiledPat->elementAti(loc);
         if (URX_TYPE(op) == URX_NOP) {
             d++;
         }
     }
     UnicodeString caseStringBuffer;
     // Make a second pass over the code, removing the NOPs by moving following
     //  code up, and patching operands that refer to code locations that
     //  are being moved.  The array of offsets from the first step is used
     //  to compute the new operand values.
     int32_t src;
     int32_t dst = 0;
     for (src=0; src<end; src++) {
         int32_t op = (int32_t)fRXPat->fCompiledPat->elementAti(src);
         int32_t opType = URX_TYPE(op);
         switch (opType) {
         case URX_NOP:
             break;
         case URX_STATE_SAVE:
         case URX_JMP:
         case URX_CTR_LOOP:
         case URX_CTR_LOOP_NG:
         case URX_RELOC_OPRND:
         case URX_JMPX:
         case URX_JMP_SAV:
         case URX_JMP_SAV_X:
             // These are instructions with operands that refer to code locations.
             {
                 int32_t  operandAddress = URX_VAL(op);
                 U_ASSERT(operandAddress>=0 && operandAddress<deltas.size());
                 int32_t fixedOperandAddress = operandAddress - deltas.elementAti(operandAddress);
                 op = URX_BUILD(opType, fixedOperandAddress);
                 fRXPat->fCompiledPat->setElementAt(op, dst);
                 dst++;
                 break;
             }
         case URX_BACKREF:
         case URX_BACKREF_I:
             {
                 int32_t where = URX_VAL(op);
                 if (where > fRXPat->fGroupMap->size()) {
                     error(U_REGEX_INVALID_BACK_REF);
                     break;
                 }
                 where = fRXPat->fGroupMap->elementAti(where-1);
                 op    = URX_BUILD(opType, where);
                 fRXPat->fCompiledPat->setElementAt(op, dst);
                 dst++;
                 fRXPat->fNeedsAltInput = TRUE;
                 break;
             }
         case URX_RESERVED_OP:
         case URX_RESERVED_OP_N:
         case URX_BACKTRACK:
         case URX_END:
         case URX_ONECHAR:
         case URX_STRING:
         case URX_STRING_LEN:
         case URX_START_CAPTURE:
         case URX_END_CAPTURE:
         case URX_STATIC_SETREF:
         case URX_STAT_SETREF_N:
         case URX_SETREF:
         case URX_DOTANY:
         case URX_FAIL:
         case URX_BACKSLASH_B:
         case URX_BACKSLASH_BU:
         case URX_BACKSLASH_G:
         case URX_BACKSLASH_X:
         case URX_BACKSLASH_Z:
         case URX_DOTANY_ALL:
         case URX_BACKSLASH_D:
         case URX_CARET:
         case URX_DOLLAR:
         case URX_CTR_INIT:
         case URX_CTR_INIT_NG:
         case URX_DOTANY_UNIX:
         case URX_STO_SP:
         case URX_LD_SP:
         case URX_STO_INP_LOC:
         case URX_LA_START:
         case URX_LA_END:
         case URX_ONECHAR_I:
         case URX_STRING_I:
         case URX_DOLLAR_M:
         case URX_CARET_M:
         case URX_CARET_M_UNIX:
         case URX_LB_START:
         case URX_LB_CONT:
         case URX_LB_END:
         case URX_LBN_CONT:
         case URX_LBN_END:
         case URX_LOOP_SR_I:
         case URX_LOOP_DOT_I:
         case URX_LOOP_C:
         case URX_DOLLAR_D:
         case URX_DOLLAR_MD:
             // These instructions are unaltered by the relocation.
             fRXPat->fCompiledPat->setElementAt(op, dst);
             dst++;
             break;
         default:
             // Some op is unaccounted for.
             U_ASSERT(FALSE);
             error(U_REGEX_INTERNAL_ERROR);
         }
     }
     fRXPat->fCompiledPat->setSize(dst);
 }
 //------------------------------------------------------------------------------
 //
 //  Error         Report a rule parse error.
 //                Only report it if no previous error has been recorded.
 //
 //------------------------------------------------------------------------------
 void RegexCompile::error(UErrorCode e) {
     if (U_SUCCESS(*fStatus)) {
         *fStatus = e;
         // Hmm. fParseErr (UParseError) line & offset fields are int32_t in public
         // API (see common/unicode/parseerr.h), while fLineNum and fCharNum are
         // int64_t. If the values of the latter are out of range for the former,
         // set them to the appropriate "field not supported" values.
         if (fLineNum > 0x7FFFFFFF) {
             fParseErr->line   = 0;
             fParseErr->offset = -1;
         } else if (fCharNum > 0x7FFFFFFF) {
             fParseErr->line   = (int32_t)fLineNum;
             fParseErr->offset = -1;
         } else {
             fParseErr->line   = (int32_t)fLineNum;
             fParseErr->offset = (int32_t)fCharNum;
         }
         UErrorCode status = U_ZERO_ERROR; // throwaway status for extracting context
         // Fill in the context.
         //   Note: extractBetween() pins supplied indicies to the string bounds.
         uprv_memset(fParseErr->preContext,  0, sizeof(fParseErr->preContext));
         uprv_memset(fParseErr->postContext, 0, sizeof(fParseErr->postContext));
         utext_extract(fRXPat->fPattern, fScanIndex-U_PARSE_CONTEXT_LEN+1, fScanIndex, fParseErr->preContext, U_PARSE_CONTEXT_LEN, &status);
         utext_extract(fRXPat->fPattern, fScanIndex, fScanIndex+U_PARSE_CONTEXT_LEN-1, fParseErr->postContext, U_PARSE_CONTEXT_LEN, &status);
     }
 }
 //
 //  Assorted Unicode character constants.
 //     Numeric because there is no portable way to enter them as literals.
 //     (Think EBCDIC).
 //
 static const UChar      chCR        = 0x0d;      // New lines, for terminating comments.
 static const UChar      chLF        = 0x0a;      // Line Feed
 static const UChar      chPound     = 0x23;      // '#', introduces a comment.
 static const UChar      chDigit0    = 0x30;      // '0'
 static const UChar      chDigit7    = 0x37;      // '9'
 static const UChar      chColon     = 0x3A;      // ':'
 static const UChar      chE         = 0x45;      // 'E'
 static const UChar      chQ         = 0x51;      // 'Q'
 //static const UChar      chN         = 0x4E;      // 'N'
 static const UChar      chP         = 0x50;      // 'P'
 static const UChar      chBackSlash = 0x5c;      // '\'  introduces a char escape
 //static const UChar      chLBracket  = 0x5b;      // '['
 static const UChar      chRBracket  = 0x5d;      // ']'
 static const UChar      chUp        = 0x5e;      // '^'
 static const UChar      chLowerP    = 0x70;
 static const UChar      chLBrace    = 0x7b;      // '{'
 static const UChar      chRBrace    = 0x7d;      // '}'
 static const UChar      chNEL       = 0x85;      //    NEL newline variant
 static const UChar      chLS        = 0x2028;    //    Unicode Line Separator
 //------------------------------------------------------------------------------
 //
 //  nextCharLL    Low Level Next Char from the regex pattern.
 //                Get a char from the string, keep track of input position
 //                     for error reporting.
 //
 //------------------------------------------------------------------------------
 UChar32  RegexCompile::nextCharLL() {
     UChar32       ch;
     if (fPeekChar != -1) {
         ch = fPeekChar;
         fPeekChar = -1;
         return ch;
     }
     // assume we're already in the right place
     ch = UTEXT_NEXT32(fRXPat->fPattern);
     if (ch == U_SENTINEL) {
         return ch;
     }
     if (ch == chCR ||
         ch == chNEL ||
         ch == chLS   ||
         (ch == chLF && fLastChar != chCR)) {
         // Character is starting a new line.  Bump up the line number, and
         //  reset the column to 0.
         fLineNum++;
         fCharNum=0;
     }
     else {
         // Character is not starting a new line.  Except in the case of a
         //   LF following a CR, increment the column position.
         if (ch != chLF) {
             fCharNum++;
         }
     }
     fLastChar = ch;
     return ch;
 }
 //------------------------------------------------------------------------------
 //
 //   peekCharLL    Low Level Character Scanning, sneak a peek at the next
 //                 character without actually getting it.
 //
 //------------------------------------------------------------------------------
 UChar32  RegexCompile::peekCharLL() {
     if (fPeekChar == -1) {
         fPeekChar = nextCharLL();
     }
     return fPeekChar;
 }
 //------------------------------------------------------------------------------
 //
 //   nextChar     for pattern scanning.  At this level, we handle stripping
 //                out comments and processing some backslash character escapes.
 //                The rest of the pattern grammar is handled at the next level up.
 //
 //------------------------------------------------------------------------------
 void RegexCompile::nextChar(RegexPatternChar &c) {
     fScanIndex = UTEXT_GETNATIVEINDEX(fRXPat->fPattern);
     c.fChar    = nextCharLL();
     c.fQuoted  = FALSE;
     if (fQuoteMode) {
         c.fQuoted = TRUE;
         if ((c.fChar==chBackSlash && peekCharLL()==chE && ((fModeFlags & UREGEX_LITERAL) == 0)) ||
             c.fChar == (UChar32)-1) {
             fQuoteMode = FALSE;  //  Exit quote mode,
             nextCharLL();        // discard the E
             nextChar(c);         // recurse to get the real next char
         }
     }
     else if (fInBackslashQuote) {
         // The current character immediately follows a '\'
         // Don't check for any further escapes, just return it as-is.
         // Don't set c.fQuoted, because that would prevent the state machine from
         //    dispatching on the character.
         fInBackslashQuote = FALSE;
     }
     else
     {
         // We are not in a \Q quoted region \E of the source.
         //
         if (fModeFlags & UREGEX_COMMENTS) {
             //
             // We are in free-spacing and comments mode.
             //  Scan through any white space and comments, until we
             //  reach a significant character or the end of inut.
             for (;;) {
                 if (c.fChar == (UChar32)-1) {
                     break;     // End of Input
                 }
                 if  (c.fChar == chPound && fEOLComments == TRUE) {
                     // Start of a comment.  Consume the rest of it, until EOF or a new line
                     for (;;) {
                         c.fChar = nextCharLL();
                         if (c.fChar == (UChar32)-1 ||  // EOF
                             c.fChar == chCR        ||
                             c.fChar == chLF        ||
                             c.fChar == chNEL       ||
                             c.fChar == chLS)       {
                             break;
                         }
                     }
                 }
                 // TODO:  check what Java & Perl do with non-ASCII white spaces.  Ticket 6061.
                 if (PatternProps::isWhiteSpace(c.fChar) == FALSE) {
                     break;
                 }
                 c.fChar = nextCharLL();
             }
         }
         //
         //  check for backslash escaped characters.
         //
         if (c.fChar == chBackSlash) {
             int64_t pos = UTEXT_GETNATIVEINDEX(fRXPat->fPattern);
             if (RegexStaticSets::gStaticSets->fUnescapeCharSet.contains(peekCharLL())) {
                 //
                 // A '\' sequence that is handled by ICU's standard unescapeAt function.
                 //   Includes \uxxxx, \n, \r, many others.
                 //   Return the single equivalent character.
                 //
                 nextCharLL();                 // get & discard the peeked char.
                 c.fQuoted = TRUE;
                 if (UTEXT_FULL_TEXT_IN_CHUNK(fRXPat->fPattern, fPatternLength)) {
                     int32_t endIndex = (int32_t)pos;
                     c.fChar = u_unescapeAt(uregex_ucstr_unescape_charAt, &endIndex, (int32_t)fPatternLength, (void *)fRXPat->fPattern->chunkContents);
                     if (endIndex == pos) {
                         error(U_REGEX_BAD_ESCAPE_SEQUENCE);
                     }
                     fCharNum += endIndex - pos;
                     UTEXT_SETNATIVEINDEX(fRXPat->fPattern, endIndex);
                 } else {
                     int32_t offset = 0;
                     struct URegexUTextUnescapeCharContext context = U_REGEX_UTEXT_UNESCAPE_CONTEXT(fRXPat->fPattern);
                     UTEXT_SETNATIVEINDEX(fRXPat->fPattern, pos);
                     c.fChar = u_unescapeAt(uregex_utext_unescape_charAt, &offset, INT32_MAX, &context);
                     if (offset == 0) {
                         error(U_REGEX_BAD_ESCAPE_SEQUENCE);
                     } else if (context.lastOffset == offset) {
                         UTEXT_PREVIOUS32(fRXPat->fPattern);
                     } else if (context.lastOffset != offset-1) {
                         utext_moveIndex32(fRXPat->fPattern, offset - context.lastOffset - 1);
                     }
                     fCharNum += offset;
                 }
             }
             else if (peekCharLL() == chDigit0) {
                 //  Octal Escape, using Java Regexp Conventions
                 //    which are \0 followed by 1-3 octal digits.
                 //    Different from ICU Unescape handling of Octal, which does not
                 //    require the leading 0.
                 //  Java also has the convention of only consuming 2 octal digits if
                 //    the three digit number would be > 0xff
                 //
                 c.fChar = 0;
                 nextCharLL();    // Consume the initial 0.
                 int index;
                 for (index=0; index<3; index++) {
                     int32_t ch = peekCharLL();
                     if (ch<chDigit0 || ch>chDigit7) {
                         if (index==0) {
                            // \0 is not followed by any octal digits.
                            error(U_REGEX_BAD_ESCAPE_SEQUENCE);
                         }
                         break;
                     }
                     c.fChar <<= 3;
                     c.fChar += ch&7;
                     if (c.fChar <= 255) {
                         nextCharLL();
                     } else {
                         // The last digit made the number too big.  Forget we saw it.
                         c.fChar >>= 3;
                     }
                 }
                 c.fQuoted = TRUE;
             }
             else if (peekCharLL() == chQ) {
                 //  "\Q"  enter quote mode, which will continue until "\E"
                 fQuoteMode = TRUE;
                 nextCharLL();       // discard the 'Q'.
                 nextChar(c);        // recurse to get the real next char.
             }
             else
             {
                 // We are in a '\' escape that will be handled by the state table scanner.
                 // Just return the backslash, but remember that the following char is to
                 //  be taken literally.
                 fInBackslashQuote = TRUE;
             }
         }
     }
     // re-enable # to end-of-line comments, in case they were disabled.
     // They are disabled by the parser upon seeing '(?', but this lasts for
     //  the fetching of the next character only.
     fEOLComments = TRUE;
     // putc(c.fChar, stdout);
 }
 //------------------------------------------------------------------------------
 //
 //  scanNamedChar
  //            Get a UChar32 from a \N{UNICODE CHARACTER NAME} in the pattern.
 //
 //             The scan position will be at the 'N'.  On return
 //             the scan position should be just after the '}'
 //
 //             Return the UChar32
 //
 //------------------------------------------------------------------------------
 UChar32  RegexCompile::scanNamedChar() {
     if (U_FAILURE(*fStatus)) {
         return 0;
     }
     nextChar(fC);
     if (fC.fChar != chLBrace) {
         error(U_REGEX_PROPERTY_SYNTAX);
         return 0;
     }
     UnicodeString  charName;
     for (;;) {
         nextChar(fC);
         if (fC.fChar == chRBrace) {
             break;
         }
         if (fC.fChar == -1) {
             error(U_REGEX_PROPERTY_SYNTAX);
             return 0;
         }
         charName.append(fC.fChar);
     }
     char name[100];
     if (!uprv_isInvariantUString(charName.getBuffer(), charName.length()) ||
          (uint32_t)charName.length()>=sizeof(name)) {
         // All Unicode character names have only invariant characters.
         // The API to get a character, given a name, accepts only char *, forcing us to convert,
         //   which requires this error check
         error(U_REGEX_PROPERTY_SYNTAX);
         return 0;
     }
     charName.extract(0, charName.length(), name, sizeof(name), US_INV);
     UChar32  theChar = u_charFromName(U_UNICODE_CHAR_NAME, name, fStatus);
     if (U_FAILURE(*fStatus)) {
         error(U_REGEX_PROPERTY_SYNTAX);
     }
     nextChar(fC);      // Continue overall regex pattern processing with char after the '}'
     return theChar;
 }
 //------------------------------------------------------------------------------
 //
 //  scanProp   Construct a UnicodeSet from the text at the current scan
 //             position, which will be of the form \p{whaterver}
 //
 //             The scan position will be at the 'p' or 'P'.  On return
 //             the scan position should be just after the '}'
 //
 //             Return a UnicodeSet, constructed from the \P pattern,
 //             or NULL if the pattern is invalid.
 //
 //------------------------------------------------------------------------------
 UnicodeSet *RegexCompile::scanProp() {
     UnicodeSet    *uset = NULL;
     if (U_FAILURE(*fStatus)) {
         return NULL;
     }
     U_ASSERT(fC.fChar == chLowerP || fC.fChar == chP);
     UBool negated = (fC.fChar == chP);
     UnicodeString propertyName;
     nextChar(fC);
     if (fC.fChar != chLBrace) {
         error(U_REGEX_PROPERTY_SYNTAX);
         return NULL;
     }
     for (;;) {
         nextChar(fC);
         if (fC.fChar == chRBrace) {
             break;
         }
         if (fC.fChar == -1) {
             // Hit the end of the input string without finding the closing '}'
             error(U_REGEX_PROPERTY_SYNTAX);
             return NULL;
         }
         propertyName.append(fC.fChar);
     }
     uset = createSetForProperty(propertyName, negated);
     nextChar(fC);    // Move input scan to position following the closing '}'
     return uset;
 }
 //------------------------------------------------------------------------------
 //
 //  scanPosixProp   Construct a UnicodeSet from the text at the current scan
 //             position, which is expected be of the form [:property expression:]
 //
 //             The scan position will be at the opening ':'.  On return
 //             the scan position must be on the closing ']'
 //
 //             Return a UnicodeSet constructed from the pattern,
 //             or NULL if this is not a valid POSIX-style set expression.
 //             If not a property expression, restore the initial scan position
 //                (to the opening ':')
 //
 //               Note:  the opening '[:' is not sufficient to guarantee that
 //                      this is a [:property:] expression.
 //                      [:'+=,] is a perfectly good ordinary set expression that
 //                              happens to include ':' as one of its characters.
 //
 //------------------------------------------------------------------------------
 UnicodeSet *RegexCompile::scanPosixProp() {
     UnicodeSet    *uset = NULL;
     if (U_FAILURE(*fStatus)) {
         return NULL;
     }
     U_ASSERT(fC.fChar == chColon);
     // Save the scanner state.
     // TODO:  move this into the scanner, with the state encapsulated in some way.  Ticket 6062
     int64_t     savedScanIndex        = fScanIndex;
     int64_t     savedNextIndex        = UTEXT_GETNATIVEINDEX(fRXPat->fPattern);
     UBool       savedQuoteMode        = fQuoteMode;
     UBool       savedInBackslashQuote = fInBackslashQuote;
     UBool       savedEOLComments      = fEOLComments;
     int64_t     savedLineNum          = fLineNum;
     int64_t     savedCharNum          = fCharNum;
     UChar32     savedLastChar         = fLastChar;
     UChar32     savedPeekChar         = fPeekChar;
     RegexPatternChar savedfC          = fC;
     // Scan for a closing ].   A little tricky because there are some perverse
     //   edge cases possible.  "[:abc\Qdef:] \E]"  is a valid non-property expression,
     //   ending on the second closing ].
     UnicodeString propName;
     UBool         negated  = FALSE;
     // Check for and consume the '^' in a negated POSIX property, e.g.  [:^Letter:]
     nextChar(fC);
     if (fC.fChar == chUp) {
        negated = TRUE;
        nextChar(fC);
     }
     // Scan for the closing ":]", collecting the property name along the way.
     UBool  sawPropSetTerminator = FALSE;
     for (;;) {
         propName.append(fC.fChar);
         nextChar(fC);
         if (fC.fQuoted || fC.fChar == -1) {
             // Escaped characters or end of input - either says this isn't a [:Property:]
             break;
         }
         if (fC.fChar == chColon) {
             nextChar(fC);
             if (fC.fChar == chRBracket) {
                 sawPropSetTerminator = TRUE;
             }
             break;
         }
     }
     if (sawPropSetTerminator) {
         uset = createSetForProperty(propName, negated);
     }
     else
     {
         // No closing ":]".
         //  Restore the original scan position.
         //  The main scanner will retry the input as a normal set expression,
         //    not a [:Property:] expression.
         fScanIndex        = savedScanIndex;
         fQuoteMode        = savedQuoteMode;
         fInBackslashQuote = savedInBackslashQuote;
         fEOLComments      = savedEOLComments;
         fLineNum          = savedLineNum;
         fCharNum          = savedCharNum;
         fLastChar         = savedLastChar;
         fPeekChar         = savedPeekChar;
         fC                = savedfC;
         UTEXT_SETNATIVEINDEX(fRXPat->fPattern, savedNextIndex);
     }
     return uset;
 }
 static inline void addIdentifierIgnorable(UnicodeSet *set, UErrorCode& ec) {
     set->add(0, 8).add(0x0e, 0x1b).add(0x7f, 0x9f);
     addCategory(set, U_GC_CF_MASK, ec);
 }
 //
 //  Create a Unicode Set from a Unicode Property expression.
 //     This is common code underlying both \p{...} ane [:...:] expressions.
 //     Includes trying the Java "properties" that aren't supported as
 //     normal ICU UnicodeSet properties
 //
 static const UChar posSetPrefix[] = {0x5b, 0x5c, 0x70, 0x7b, 0}; // "[\p{"
 static const UChar negSetPrefix[] = {0x5b, 0x5c, 0x50, 0x7b, 0}; // "[\P{"
 UnicodeSet *RegexCompile::createSetForProperty(const UnicodeString &propName, UBool negated) {
     UnicodeString   setExpr;
     UnicodeSet      *set;
     uint32_t        usetFlags = 0;
     if (U_FAILURE(*fStatus)) {
         return NULL;
     }
     //
     //  First try the property as we received it
     //
     if (negated) {
         setExpr.append(negSetPrefix, -1);
     } else {
         setExpr.append(posSetPrefix, -1);
     }
     setExpr.append(propName);
     setExpr.append(chRBrace);
     setExpr.append(chRBracket);
     if (fModeFlags & UREGEX_CASE_INSENSITIVE) {
         usetFlags |= USET_CASE_INSENSITIVE;
     }
     set = new UnicodeSet(setExpr, usetFlags, NULL, *fStatus);
     if (U_SUCCESS(*fStatus)) {
        return set;
     }
     delete set;
     set = NULL;
     //
     //  The property as it was didn't work.
     //  Do [:word:]. It is not recognized as a property by UnicodeSet.  "word" not standard POSIX
     //     or standard Java, but many other regular expression packages do recognize it.
     if (propName.caseCompare(UNICODE_STRING_SIMPLE("word"), 0) == 0) {
         *fStatus = U_ZERO_ERROR;
         set = new UnicodeSet(*(fRXPat->fStaticSets[URX_ISWORD_SET]));
         if (set == NULL) {
             *fStatus = U_MEMORY_ALLOCATION_ERROR;
             return set;
         }
         if (negated) {
             set->complement();
         }
         return set;
     }
     //    Do Java fixes -
     //       InGreek -> InGreek or Coptic, that being the official Unicode name for that block.
     //       InCombiningMarksforSymbols -> InCombiningDiacriticalMarksforSymbols.
     //
     //       Note on Spaces:  either "InCombiningMarksForSymbols" or "InCombining Marks for Symbols"
     //                        is accepted by Java.  The property part of the name is compared
     //                        case-insenstively.  The spaces must be exactly as shown, either
     //                        all there, or all omitted, with exactly one at each position
     //                        if they are present.  From checking against JDK 1.6
     //
     //       This code should be removed when ICU properties support the Java  compatibility names
     //          (ICU 4.0?)
     //
     UnicodeString mPropName = propName;
     if (mPropName.caseCompare(UNICODE_STRING_SIMPLE("InGreek"), 0) == 0) {
         mPropName = UNICODE_STRING_SIMPLE("InGreek and Coptic");
     }
     if (mPropName.caseCompare(UNICODE_STRING_SIMPLE("InCombining Marks for Symbols"), 0) == 0 ||
         mPropName.caseCompare(UNICODE_STRING_SIMPLE("InCombiningMarksforSymbols"), 0) == 0) {
         mPropName = UNICODE_STRING_SIMPLE("InCombining Diacritical Marks for Symbols");
     }
     else if (mPropName.compare(UNICODE_STRING_SIMPLE("all")) == 0) {
         mPropName = UNICODE_STRING_SIMPLE("javaValidCodePoint");
     }
     //    See if the property looks like a Java "InBlockName", which
     //    we will recast as "Block=BlockName"
     //
     static const UChar IN[] = {0x49, 0x6E, 0};  // "In"
     static const UChar BLOCK[] = {0x42, 0x6C, 0x6f, 0x63, 0x6b, 0x3d, 00};  // "Block="
     if (mPropName.startsWith(IN, 2) && propName.length()>=3) {
         setExpr.truncate(4);   // Leaves "[\p{", or "[\P{"
         setExpr.append(BLOCK, -1);
         setExpr.append(UnicodeString(mPropName, 2));  // Property with the leading "In" removed.
         setExpr.append(chRBrace);
         setExpr.append(chRBracket);
         *fStatus = U_ZERO_ERROR;
         set = new UnicodeSet(setExpr, usetFlags, NULL, *fStatus);
         if (U_SUCCESS(*fStatus)) {
             return set;
         }
         delete set;
         set = NULL;
     }
     if (propName.startsWith(UNICODE_STRING_SIMPLE("java")) ||
         propName.compare(UNICODE_STRING_SIMPLE("all")) == 0)
     {
         UErrorCode localStatus = U_ZERO_ERROR;
         //setExpr.remove();
         set = new UnicodeSet();
         //
         //  Try the various Java specific properties.
         //   These all begin with "java"
         //
         if (mPropName.compare(UNICODE_STRING_SIMPLE("javaDefined")) == 0) {
             addCategory(set, U_GC_CN_MASK, localStatus);
             set->complement();
         }
         else if (mPropName.compare(UNICODE_STRING_SIMPLE("javaDigit")) == 0) {
             addCategory(set, U_GC_ND_MASK, localStatus);
         }
         else if (mPropName.compare(UNICODE_STRING_SIMPLE("javaIdentifierIgnorable")) == 0) {
             addIdentifierIgnorable(set, localStatus);
         }
         else if (mPropName.compare(UNICODE_STRING_SIMPLE("javaISOControl")) == 0) {
             set->add(0, 0x1F).add(0x7F, 0x9F);
         }
         else if (mPropName.compare(UNICODE_STRING_SIMPLE("javaJavaIdentifierPart")) == 0) {
             addCategory(set, U_GC_L_MASK, localStatus);
             addCategory(set, U_GC_SC_MASK, localStatus);
             addCategory(set, U_GC_PC_MASK, localStatus);
             addCategory(set, U_GC_ND_MASK, localStatus);
             addCategory(set, U_GC_NL_MASK, localStatus);
             addCategory(set, U_GC_MC_MASK, localStatus);
             addCategory(set, U_GC_MN_MASK, localStatus);
             addIdentifierIgnorable(set, localStatus);
         }
         else if (mPropName.compare(UNICODE_STRING_SIMPLE("javaJavaIdentifierStart")) == 0) {
             addCategory(set, U_GC_L_MASK, localStatus);
             addCategory(set, U_GC_NL_MASK, localStatus);
             addCategory(set, U_GC_SC_MASK, localStatus);
             addCategory(set, U_GC_PC_MASK, localStatus);
         }
         else if (mPropName.compare(UNICODE_STRING_SIMPLE("javaLetter")) == 0) {
             addCategory(set, U_GC_L_MASK, localStatus);
         }
         else if (mPropName.compare(UNICODE_STRING_SIMPLE("javaLetterOrDigit")) == 0) {
             addCategory(set, U_GC_L_MASK, localStatus);
             addCategory(set, U_GC_ND_MASK, localStatus);
         }
         else if (mPropName.compare(UNICODE_STRING_SIMPLE("javaLowerCase")) == 0) {
             addCategory(set, U_GC_LL_MASK, localStatus);
         }
         else if (mPropName.compare(UNICODE_STRING_SIMPLE("javaMirrored")) == 0) {
             set->applyIntPropertyValue(UCHAR_BIDI_MIRRORED, 1, localStatus);
         }
         else if (mPropName.compare(UNICODE_STRING_SIMPLE("javaSpaceChar")) == 0) {
             addCategory(set, U_GC_Z_MASK, localStatus);
         }
         else if (mPropName.compare(UNICODE_STRING_SIMPLE("javaSupplementaryCodePoint")) == 0) {
             set->add(0x10000, UnicodeSet::MAX_VALUE);
         }
         else if (mPropName.compare(UNICODE_STRING_SIMPLE("javaTitleCase")) == 0) {
             addCategory(set, U_GC_LT_MASK, localStatus);
         }
         else if (mPropName.compare(UNICODE_STRING_SIMPLE("javaUnicodeIdentifierStart")) == 0) {
             addCategory(set, U_GC_L_MASK, localStatus);
             addCategory(set, U_GC_NL_MASK, localStatus);
         }
         else if (mPropName.compare(UNICODE_STRING_SIMPLE("javaUnicodeIdentifierPart")) == 0) {
             addCategory(set, U_GC_L_MASK, localStatus);
             addCategory(set, U_GC_PC_MASK, localStatus);
             addCategory(set, U_GC_ND_MASK, localStatus);
             addCategory(set, U_GC_NL_MASK, localStatus);
             addCategory(set, U_GC_MC_MASK, localStatus);
             addCategory(set, U_GC_MN_MASK, localStatus);
             addIdentifierIgnorable(set, localStatus);
         }
         else if (mPropName.compare(UNICODE_STRING_SIMPLE("javaUpperCase")) == 0) {
             addCategory(set, U_GC_LU_MASK, localStatus);
         }
         else if (mPropName.compare(UNICODE_STRING_SIMPLE("javaValidCodePoint")) == 0) {
             set->add(0, UnicodeSet::MAX_VALUE);
         }
         else if (mPropName.compare(UNICODE_STRING_SIMPLE("javaWhitespace")) == 0) {
             addCategory(set, U_GC_Z_MASK, localStatus);
             set->removeAll(UnicodeSet().add(0xa0).add(0x2007).add(0x202f));
             set->add(9, 0x0d).add(0x1c, 0x1f);
         }
         else if (mPropName.compare(UNICODE_STRING_SIMPLE("all")) == 0) {
             set->add(0, UnicodeSet::MAX_VALUE);
         }
         if (U_SUCCESS(localStatus) && !set->isEmpty()) {
             *fStatus = U_ZERO_ERROR;
             if (usetFlags & USET_CASE_INSENSITIVE) {
                 set->closeOver(USET_CASE_INSENSITIVE);
             }
             if (negated) {
                 set->complement();
             }
             return set;
         }
         delete set;
         set = NULL;
     }
     error(*fStatus);
     return NULL;
 }
 //
 //  SetEval   Part of the evaluation of [set expressions].
 //            Perform any pending (stacked) operations with precedence
 //            equal or greater to that of the next operator encountered
 //            in the expression.
 //
 void RegexCompile::setEval(int32_t nextOp) {
     UnicodeSet *rightOperand = NULL;
     UnicodeSet *leftOperand  = NULL;
     for (;;) {
         U_ASSERT(fSetOpStack.empty()==FALSE);
         int32_t pendingSetOperation = fSetOpStack.peeki();
         if ((pendingSetOperation&0xffff0000) < (nextOp&0xffff0000)) {
             break;
         }
         fSetOpStack.popi();
         U_ASSERT(fSetStack.empty() == FALSE);
         rightOperand = (UnicodeSet *)fSetStack.peek();
         switch (pendingSetOperation) {
             case setNegation:
                 rightOperand->complement();
                 break;
             case setCaseClose:
                 // TODO: need a simple close function.  Ticket 6065
                 rightOperand->closeOver(USET_CASE_INSENSITIVE);
                 rightOperand->removeAllStrings();
                 break;
             case setDifference1:
             case setDifference2:
                 fSetStack.pop();
                 leftOperand = (UnicodeSet *)fSetStack.peek();
                 leftOperand->removeAll(*rightOperand);
                 delete rightOperand;
                 break;
             case setIntersection1:
             case setIntersection2:
                 fSetStack.pop();
                 leftOperand = (UnicodeSet *)fSetStack.peek();
                 leftOperand->retainAll(*rightOperand);
                 delete rightOperand;
                 break;
             case setUnion:
                 fSetStack.pop();
                 leftOperand = (UnicodeSet *)fSetStack.peek();
                 leftOperand->addAll(*rightOperand);
                 delete rightOperand;
                 break;
             default:
                 U_ASSERT(FALSE);
                 break;
             }
         }
     }
 void RegexCompile::setPushOp(int32_t op) {
     setEval(op);
     fSetOpStack.push(op, *fStatus);
     fSetStack.push(new UnicodeSet(), *fStatus);
 }
 U_NAMESPACE_END
 #endif  // !UCONFIG_NO_REGULAR_EXPRESSIONS

The Tor Browser / annotate

intl/icu/source/i18n/regexcmp.cpp@fc2d59ddac77 (annotated)

intl/icu/source/i18n/regexcmp.cpp