icuSources/common/ruleiter.cpp

   1 // © 2016 and later: Unicode, Inc. and others.
   2 // License & terms of use: http://www.unicode.org/copyright.html
   3 /*
   4 **********************************************************************
   5 * Copyright (c) 2003-2011, International Business Machines
   6 * Corporation and others.  All Rights Reserved.
   7 **********************************************************************
   8 * Author: Alan Liu
   9 * Created: September 24 2003
  10 * Since: ICU 2.8
  11 **********************************************************************
  12 */
  13 #include "ruleiter.h"
  14 #include "unicode/parsepos.h"
  15 #include "unicode/symtable.h"
  16 #include "unicode/unistr.h"
  17 #include "unicode/utf16.h"
  18 #include "patternprops.h"
  19
  20 /* \U87654321 or \ud800\udc00 */
  21 #define MAX_U_NOTATION_LEN 12
  22
  23 U_NAMESPACE_BEGIN
  24
  25 RuleCharacterIterator::RuleCharacterIterator(const UnicodeString& theText, const SymbolTable* theSym,
  26                       ParsePosition& thePos) :
  27     text(theText),
  28     pos(thePos),
  29     sym(theSym),
  30     buf(0),
  31     bufPos(0)
  32 {}
  33
  34 UBool RuleCharacterIterator::atEnd() const {
  35     return buf == 0 && pos.getIndex() == text.length();
  36 }
  37
  38 UChar32 RuleCharacterIterator::next(int32_t options, UBool& isEscaped, UErrorCode& ec) {
  39     if (U_FAILURE(ec)) return DONE;
  40
  41     UChar32 c = DONE;
  42     isEscaped = FALSE;
  43
  44     for (;;) {
  45         c = _current();
  46         _advance(U16_LENGTH(c));
  47
  48         if (c == SymbolTable::SYMBOL_REF && buf == 0 &&
  49             (options & PARSE_VARIABLES) != 0 && sym != 0) {
  50             UnicodeString name = sym->parseReference(text, pos, text.length());
  51             // If name is empty there was an isolated SYMBOL_REF;
  52             // return it.  Caller must be prepared for this.
  53             if (name.length() == 0) {
  54                 break;
  55             }
  56             bufPos = 0;
  57             buf = sym->lookup(name);
  58             if (buf == 0) {
  59                 ec = U_UNDEFINED_VARIABLE;
  60                 return DONE;
  61             }
  62             // Handle empty variable value
  63             if (buf->length() == 0) {
  64                 buf = 0;
  65             }
  66             continue;
  67         }
  68
  69         if ((options & SKIP_WHITESPACE) != 0 && PatternProps::isWhiteSpace(c)) {
  70             continue;
  71         }
  72
  73         if (c == 0x5C /*'\\'*/ && (options & PARSE_ESCAPES) != 0) {
  74             UnicodeString tempEscape;
  75             int32_t offset = 0;
  76             c = lookahead(tempEscape, MAX_U_NOTATION_LEN).unescapeAt(offset);
  77             jumpahead(offset);
  78             isEscaped = TRUE;
  79             if (c < 0) {
  80                 ec = U_MALFORMED_UNICODE_ESCAPE;
  81                 return DONE;
  82             }
  83         }
  84
  85         break;
  86     }
  87
  88     return c;
  89 }
  90
  91 void RuleCharacterIterator::getPos(RuleCharacterIterator::Pos& p) const {
  92     p.buf = buf;
  93     p.pos = pos.getIndex();
  94     p.bufPos = bufPos;
  95 }
  96
  97 void RuleCharacterIterator::setPos(const RuleCharacterIterator::Pos& p) {
  98     buf = p.buf;
  99     pos.setIndex(p.pos);
 100     bufPos = p.bufPos;
 101 }
 102
 103 void RuleCharacterIterator::skipIgnored(int32_t options) {
 104     if ((options & SKIP_WHITESPACE) != 0) {
 105         for (;;) {
 106             UChar32 a = _current();
 107             if (!PatternProps::isWhiteSpace(a)) break;
 108             _advance(U16_LENGTH(a));
 109         }
 110     }
 111 }
 112
 113 UnicodeString& RuleCharacterIterator::lookahead(UnicodeString& result, int32_t maxLookAhead) const {
 114     if (maxLookAhead < 0) {
 115         maxLookAhead = 0x7FFFFFFF;
 116     }
 117     if (buf != 0) {
 118         buf->extract(bufPos, maxLookAhead, result);
 119     } else {
 120         text.extract(pos.getIndex(), maxLookAhead, result);
 121     }
 122     return result;
 123 }
 124
 125 void RuleCharacterIterator::jumpahead(int32_t count) {
 126     _advance(count);
 127 }
 128
 129 /*
 130 UnicodeString& RuleCharacterIterator::toString(UnicodeString& result) const {
 131     int32_t b = pos.getIndex();
 132     text.extract(0, b, result);
 133     return result.append((UChar) 0x7C).append(text, b, 0x7FFFFFFF); // Insert '|' at index
 134 }
 135 */
 136
 137 UChar32 RuleCharacterIterator::_current() const {
 138     if (buf != 0) {
 139         return buf->char32At(bufPos);
 140     } else {
 141         int i = pos.getIndex();
 142         return (i < text.length()) ? text.char32At(i) : (UChar32)DONE;
 143     }
 144 }
 145
 146 void RuleCharacterIterator::_advance(int32_t count) {
 147     if (buf != 0) {
 148         bufPos += count;
 149         if (bufPos == buf->length()) {
 150             buf = 0;
 151         }
 152     } else {
 153         pos.setIndex(pos.getIndex() + count);
 154         if (pos.getIndex() > text.length()) {
 155             pos.setIndex(text.length());
 156         }
 157     }
 158 }
 159
 160 U_NAMESPACE_END
 161
 162 //eof