icuSources/common/symtable.h

   1 /*
   2 **********************************************************************
   3 *   Copyright (c) 2000, International Business Machines
   4 *   Corporation and others.  All Rights Reserved.
   5 **********************************************************************
   6 *   Date        Name        Description
   7 *   02/04/00    aliu        Creation.
   8 **********************************************************************
   9 */
  10 #ifndef SYMTABLE_H
  11 #define SYMTABLE_H
  12
  13 #include "unicode/utypes.h"
  14 #include "unicode/uobject.h"
  15
  16 U_NAMESPACE_BEGIN
  17
  18 class ParsePosition;
  19 class UnicodeFunctor;
  20 class UnicodeSet;
  21 class UnicodeString;
  22
  23 /**
  24  * An interface that maps strings to objects.  This interface defines
  25  * both lookup protocol and parsing.  This allows different components
  26  * to share a symbol table and to handle name parsing uniformly.  It
  27  * is expected that client parse code look for the SYMBOL_REF
  28  * character and, when seen, attempt to parse the characters after it
  29  * using parseReference().
  30  *
  31  * <p>Currently, RuleBasedTransliterator and UnicodeSet use this
  32  * interface to share variable definitions.
  33  */
  34 class SymbolTable /* not : public UObject because this is an interface/mixin class */ {
  35 public:
  36
  37     /**
  38      * The character preceding a symbol reference name.
  39      */
  40     enum { SYMBOL_REF = 0x0024 /*$*/ };
  41
  42     /**
  43      * Destructor.
  44      */
  45     virtual inline ~SymbolTable() {};
  46
  47     /**
  48      * Lookup the characters associated with this string and return it.
  49      * Return <tt>NULL</tt> if no such name exists.  The resultant
  50      * string may have length zero.
  51      */
  52     virtual const UnicodeString* lookup(const UnicodeString& s) const = 0;
  53
  54     /**
  55      * Lookup the UnicodeMatcher associated with the given character, and
  56      * return it.  Return <tt>null</tt> if not found.
  57      */
  58     virtual const UnicodeFunctor* lookupMatcher(UChar32 ch) const = 0;
  59
  60     /**
  61      * Parse a symbol reference name from the given string, starting
  62      * at the given position.  If no valid symbol reference name is
  63      * found, return an empty string.
  64      * @param text the text to parse for the name
  65      * @param pos on entry, the index of the first character to parse.
  66      * This is the character following the SYMBOL_REF character.  On
  67      * exit, the index after the last parsed character.
  68      * @param limit the index after the last character to be parsed.
  69      * @return the parsed name or an empty string.
  70      */
  71     virtual UnicodeString parseReference(const UnicodeString& text,
  72                                          ParsePosition& pos, int32_t limit) const = 0;
  73 };
  74 U_NAMESPACE_END
  75
  76
  77 #endif