icuSources/i18n/regexcmp.h

   1 // © 2016 and later: Unicode, Inc. and others.
   2 // License & terms of use: http://www.unicode.org/copyright.html
   3 //
   4 //  regexcmp.h
   5 //
   6 //  Copyright (C) 2002-2016, International Business Machines Corporation and others.
   7 //  All Rights Reserved.
   8 //
   9 //  This file contains declarations for the class RegexCompile
  10 //
  11 //  This class is internal to the regular expression implementation.
  12 //  For the public Regular Expression API, see the file "unicode/regex.h"
  13 //
  14
  15
  16 #ifndef RBBISCAN_H
  17 #define RBBISCAN_H
  18
  19 #include "unicode/utypes.h"
  20 #if !UCONFIG_NO_REGULAR_EXPRESSIONS
  21
  22 #include "unicode/parseerr.h"
  23 #include "unicode/uniset.h"
  24 #include "unicode/uobject.h"
  25 #include "unicode/utext.h"
  26 #include "uhash.h"
  27 #include "uvector.h"
  28 #include "uvectr32.h"
  29
  30
  31
  32 U_NAMESPACE_BEGIN
  33
  34
  35 //--------------------------------------------------------------------------------
  36 //
  37 //  class RegexCompile    Contains the regular expression compiler.
  38 //
  39 //--------------------------------------------------------------------------------
  40 struct  RegexTableEl;
  41 class   RegexPattern;
  42
  43
  44 class U_I18N_API RegexCompile : public UMemory {
  45 public:
  46
  47     enum {
  48         kStackSize = 100            // The size of the state stack for
  49     };                              //   pattern parsing.  Corresponds roughly
  50                                     //   to the depth of parentheses nesting
  51                                     //   that is allowed in the rules.
  52
  53     struct RegexPatternChar {
  54         UChar32             fChar;
  55         UBool               fQuoted;
  56     };
  57
  58     RegexCompile(RegexPattern *rp, UErrorCode &e);
  59
  60     void       compile(const UnicodeString &pat, UParseError &pp, UErrorCode &e);
  61     void       compile(UText *pat, UParseError &pp, UErrorCode &e);
  62
  63
  64     virtual    ~RegexCompile();
  65
  66     void        nextChar(RegexPatternChar &c);      // Get the next char from the input stream.
  67
  68     static void cleanup();                       // Memory cleanup
  69
  70
  71
  72     // Categories of parentheses in pattern.
  73     //   The category is saved in the compile-time parentheses stack frame, and
  74     //   determines the code to be generated when the matching close ) is encountered.
  75     enum EParenClass {
  76         plain        = -1,               // No special handling
  77         capturing    = -2,
  78         atomic       = -3,
  79         lookAhead    = -4,
  80         negLookAhead = -5,
  81         flags        = -6,
  82         lookBehind   = -7,
  83         lookBehindN  = -8
  84     };
  85
  86 private:
  87
  88
  89     UBool       doParseActions(int32_t a);
  90     void        error(UErrorCode e);                   // error reporting convenience function.
  91
  92     UChar32     nextCharLL();
  93     UChar32     peekCharLL();
  94     UnicodeSet  *scanProp();
  95     UnicodeSet  *scanPosixProp();
  96     void        handleCloseParen();
  97     int32_t     blockTopLoc(UBool reserve);          // Locate a position in the compiled pattern
  98                                                      //  at the top of the just completed block
  99                                                      //  or operation, and optionally ensure that
 100                                                      //  there is space to add an opcode there.
 101     void        compileSet(UnicodeSet *theSet);      // Generate the compiled pattern for
 102                                                      //   a reference to a UnicodeSet.
 103     void        compileInterval(int32_t InitOp,      // Generate the code for a {min,max} quantifier.
 104                                int32_t LoopOp);
 105     UBool       compileInlineInterval();             // Generate inline code for a {min,max} quantifier
 106     void        literalChar(UChar32 c);              // Compile a literal char
 107     void        fixLiterals(UBool split=FALSE);      // Generate code for pending literal characters.
 108     void        insertOp(int32_t where);             // Open up a slot for a new op in the
 109                                                      //   generated code at the specified location.
 110     void        appendOp(int32_t op);                // Append a new op to the compiled pattern.
 111     void        appendOp(int32_t type, int32_t val); // Build & append a new op to the compiled pattern.
 112     int32_t     buildOp(int32_t type, int32_t val);  // Construct a new pcode instruction.
 113     int32_t     allocateData(int32_t size);          // Allocate space in the matcher data area.
 114                                                      //   Return index of the newly allocated data.
 115     int32_t     allocateStackData(int32_t size);     // Allocate space in the match back-track stack frame.
 116                                                      //   Return offset index in the frame.
 117     int32_t     minMatchLength(int32_t start,
 118                                int32_t end);
 119     int32_t     maxMatchLength(int32_t start,
 120                                int32_t end);
 121     void        matchStartType();
 122     void        stripNOPs();
 123
 124     void        setEval(int32_t op);
 125     void        setPushOp(int32_t op);
 126     UChar32     scanNamedChar();
 127     UnicodeSet *createSetForProperty(const UnicodeString &propName, UBool negated);
 128
 129 public:   // Public for testing only.
 130     static void U_EXPORT2 findCaseInsensitiveStarters(UChar32 c, UnicodeSet *starterChars);
 131 private:
 132
 133
 134     UErrorCode                    *fStatus;
 135     RegexPattern                  *fRXPat;
 136     UParseError                   *fParseErr;
 137
 138     //
 139     //  Data associated with low level character scanning
 140     //
 141     int64_t                       fScanIndex;        // Index of current character being processed
 142                                                      //   in the rule input string.
 143     UBool                         fQuoteMode;        // Scan is in a \Q...\E quoted region
 144     UBool                         fInBackslashQuote; // Scan is between a '\' and the following char.
 145     UBool                         fEOLComments;      // When scan is just after '(?',  inhibit #... to
 146                                                      //   end of line comments, in favor of (?#...) comments.
 147     int64_t                       fLineNum;          // Line number in input file.
 148     int64_t                       fCharNum;          // Char position within the line.
 149     UChar32                       fLastChar;         // Previous char, needed to count CR-LF
 150                                                      //   as a single line, not two.
 151     UChar32                       fPeekChar;         // Saved char, if we've scanned ahead.
 152
 153
 154     RegexPatternChar              fC;                // Current char for parse state machine
 155                                                      //   processing.
 156
 157     //
 158     //   Data for the state machine that parses the regular expression.
 159     //
 160     RegexTableEl                  **fStateTable;     // State Transition Table for regex Rule
 161                                                      //   parsing.  index by p[state][char-class]
 162
 163     uint16_t                      fStack[kStackSize];  // State stack, holds state pushes
 164     int32_t                       fStackPtr;           //  and pops as specified in the state
 165                                                        //  transition rules.
 166
 167     //
 168     //  Data associated with the generation of the pcode for the match engine
 169     //
 170     int32_t                       fModeFlags;        // Match Flags.  (Case Insensitive, etc.)
 171                                                      //   Always has high bit (31) set so that flag values
 172                                                      //   on the paren stack are distinguished from relocatable
 173                                                      //   pcode addresses.
 174     int32_t                       fNewModeFlags;     // New flags, while compiling (?i, holds state
 175                                                      //   until last flag is scanned.
 176     UBool                         fSetModeFlag;      // true for (?ismx, false for (?-ismx
 177
 178     UnicodeString                 fLiteralChars;     // Literal chars or strings from the pattern are accumulated here.
 179                                                      //   Once completed, meaning that some non-literal pattern
 180                                                      //   construct is encountered, the appropriate opcodes
 181                                                      //   to match the literal will be generated, and this
 182                                                      //   string will be cleared.
 183
 184     int64_t                       fPatternLength;    // Length of the input pattern string.
 185
 186     UVector32                     fParenStack;       // parentheses stack.  Each frame consists of
 187                                                      //   the positions of compiled pattern operations
 188                                                      //   needing fixup, followed by negative value.  The
 189                                                      //   first entry in each frame is the position of the
 190                                                      //   spot reserved for use when a quantifier
 191                                                      //   needs to add a SAVE at the start of a (block)
 192                                                      //   The negative value (-1, -2,...) indicates
 193                                                      //   the kind of paren that opened the frame.  Some
 194                                                      //   need special handling on close.
 195
 196
 197     int32_t                       fMatchOpenParen;   // The position in the compiled pattern
 198                                                      //   of the slot reserved for a state save
 199                                                      //   at the start of the most recently processed
 200                                                      //   parenthesized block. Updated when processing
 201                                                      //   a close to the location for the corresponding open.
 202
 203     int32_t                       fMatchCloseParen;  // The position in the pattern of the first
 204                                                      //   location after the most recently processed
 205                                                      //   parenthesized block.
 206
 207     int32_t                       fIntervalLow;      // {lower, upper} interval quantifier values.
 208     int32_t                       fIntervalUpper;    // Placed here temporarily, when pattern is
 209                                                      //   initially scanned.  Each new interval
 210                                                      //   encountered overwrites these values.
 211                                                      //   -1 for the upper interval value means none
 212                                                      //   was specified (unlimited occurences.)
 213
 214     int64_t                       fNameStartPos;     // Starting position of a \N{NAME} name in a
 215                                                      //   pattern, valid while remainder of name is
 216                                                      //   scanned.
 217
 218     UStack                        fSetStack;         // Stack of UnicodeSets, used while evaluating
 219                                                      //   (at compile time) set expressions within
 220                                                      //   the pattern.
 221     UStack                        fSetOpStack;       // Stack of pending set operators (&&, --, union)
 222
 223     UChar32                       fLastSetLiteral;   // The last single code point added to a set.
 224                                                      //   needed when "-y" is scanned, and we need
 225                                                      //   to turn "x-y" into a range.
 226
 227     UnicodeString                *fCaptureName;      // Named Capture, the group name is built up
 228                                                      //   in this string while being scanned.
 229 };
 230
 231 // Constant values to be pushed onto fSetOpStack while scanning & evalueating [set expressions]
 232 //   The high 16 bits are the operator precedence, and the low 16 are a code for the operation itself.
 233
 234 enum SetOperations {
 235     setStart         = 0 << 16 | 1,
 236     setEnd           = 1 << 16 | 2,
 237     setNegation      = 2 << 16 | 3,
 238     setCaseClose     = 2 << 16 | 9,
 239     setDifference2   = 3 << 16 | 4,    // '--' set difference operator
 240     setIntersection2 = 3 << 16 | 5,    // '&&' set intersection operator
 241     setUnion         = 4 << 16 | 6,    // implicit union of adjacent items
 242     setDifference1   = 4 << 16 | 7,    // '-', single dash difference op, for compatibility with old UnicodeSet.
 243     setIntersection1 = 4 << 16 | 8     // '&', single amp intersection op, for compatibility with old UnicodeSet.
 244     };
 245
 246 U_NAMESPACE_END
 247 #endif   // !UCONFIG_NO_REGULAR_EXPRESSIONS
 248 #endif   // RBBISCAN_H