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Diffstat (limited to 'intl/icu/source/common/unicode/symtable.h')
-rw-r--r-- | intl/icu/source/common/unicode/symtable.h | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/intl/icu/source/common/unicode/symtable.h b/intl/icu/source/common/unicode/symtable.h new file mode 100644 index 000000000..cf2c4f0f4 --- /dev/null +++ b/intl/icu/source/common/unicode/symtable.h @@ -0,0 +1,114 @@ +// Copyright (C) 2016 and later: Unicode, Inc. and others. +// License & terms of use: http://www.unicode.org/copyright.html +/* +********************************************************************** +* Copyright (c) 2000-2005, International Business Machines +* Corporation and others. All Rights Reserved. +********************************************************************** +* Date Name Description +* 02/04/00 aliu Creation. +********************************************************************** +*/ +#ifndef SYMTABLE_H +#define SYMTABLE_H + +#include "unicode/utypes.h" +#include "unicode/uobject.h" + +/** + * \file + * \brief C++ API: An interface that defines both lookup protocol and parsing of + * symbolic names. + */ + +U_NAMESPACE_BEGIN + +class ParsePosition; +class UnicodeFunctor; +class UnicodeSet; +class UnicodeString; + +/** + * An interface that defines both lookup protocol and parsing of + * symbolic names. + * + * <p>A symbol table maintains two kinds of mappings. The first is + * between symbolic names and their values. For example, if the + * variable with the name "start" is set to the value "alpha" + * (perhaps, though not necessarily, through an expression such as + * "$start=alpha"), then the call lookup("start") will return the + * char[] array ['a', 'l', 'p', 'h', 'a']. + * + * <p>The second kind of mapping is between character values and + * UnicodeMatcher objects. This is used by RuleBasedTransliterator, + * which uses characters in the private use area to represent objects + * such as UnicodeSets. If U+E015 is mapped to the UnicodeSet [a-z], + * then lookupMatcher(0xE015) will return the UnicodeSet [a-z]. + * + * <p>Finally, a symbol table defines parsing behavior for symbolic + * names. All symbolic names start with the SYMBOL_REF character. + * When a parser encounters this character, it calls parseReference() + * with the position immediately following the SYMBOL_REF. The symbol + * table parses the name, if there is one, and returns it. + * + * @stable ICU 2.8 + */ +class U_COMMON_API SymbolTable /* not : public UObject because this is an interface/mixin class */ { +public: + + /** + * The character preceding a symbol reference name. + * @stable ICU 2.8 + */ + enum { SYMBOL_REF = 0x0024 /*$*/ }; + + /** + * Destructor. + * @stable ICU 2.8 + */ + virtual ~SymbolTable(); + + /** + * Lookup the characters associated with this string and return it. + * Return <tt>NULL</tt> if no such name exists. The resultant + * string may have length zero. + * @param s the symbolic name to lookup + * @return a string containing the name's value, or <tt>NULL</tt> if + * there is no mapping for s. + * @stable ICU 2.8 + */ + virtual const UnicodeString* lookup(const UnicodeString& s) const = 0; + + /** + * Lookup the UnicodeMatcher associated with the given character, and + * return it. Return <tt>NULL</tt> if not found. + * @param ch a 32-bit code point from 0 to 0x10FFFF inclusive. + * @return the UnicodeMatcher object represented by the given + * character, or NULL if there is no mapping for ch. + * @stable ICU 2.8 + */ + virtual const UnicodeFunctor* lookupMatcher(UChar32 ch) const = 0; + + /** + * Parse a symbol reference name from the given string, starting + * at the given position. If no valid symbol reference name is + * found, return the empty string and leave pos unchanged. That is, if the + * character at pos cannot start a name, or if pos is at or after + * text.length(), then return an empty string. This indicates an + * isolated SYMBOL_REF character. + * @param text the text to parse for the name + * @param pos on entry, the index of the first character to parse. + * This is the character following the SYMBOL_REF character. On + * exit, the index after the last parsed character. If the parse + * failed, pos is unchanged on exit. + * @param limit the index after the last character to be parsed. + * @return the parsed name, or an empty string if there is no + * valid symbolic name at the given position. + * @stable ICU 2.8 + */ + virtual UnicodeString parseReference(const UnicodeString& text, + ParsePosition& pos, int32_t limit) const = 0; +}; +U_NAMESPACE_END + +#endif |