--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/fontservices/textshaperplugin/IcuSource/common/ruleiter.h Tue Feb 02 02:02:46 2010 +0200
@@ -0,0 +1,231 @@
+/*
+**********************************************************************
+* Copyright (c) 2003-2005, International Business Machines
+* Corporation and others. All Rights Reserved.
+**********************************************************************
+* Author: Alan Liu
+* Created: September 24 2003
+* Since: ICU 2.8
+**********************************************************************
+*/
+#ifndef _RULEITER_H_
+#define _RULEITER_H_
+
+#include "unicode/utypes.h"
+
+U_NAMESPACE_BEGIN
+
+class UnicodeString;
+class ParsePosition;
+class SymbolTable;
+
+/**
+ * An iterator that returns 32-bit code points. This class is deliberately
+ * <em>not</em> related to any of the ICU character iterator classes
+ * in order to minimize complexity.
+ * @author Alan Liu
+ * @since ICU 2.8
+ */
+class U_COMMON_API RuleCharacterIterator {
+
+ // TODO: Ideas for later. (Do not implement if not needed, lest the
+ // code coverage numbers go down due to unused methods.)
+ // 1. Add a copy constructor, operator==() method.
+ // 2. Rather than return DONE, throw an exception if the end
+ // is reached -- this is an alternate usage model, probably not useful.
+
+private:
+ /**
+ * Text being iterated.
+ */
+ const UnicodeString& text;
+
+ /**
+ * Position of iterator.
+ */
+ ParsePosition& pos;
+
+ /**
+ * Symbol table used to parse and dereference variables. May be 0.
+ */
+ const SymbolTable* sym;
+
+ /**
+ * Current variable expansion, or 0 if none.
+ */
+ const UnicodeString* buf;
+
+ /**
+ * Position within buf. Meaningless if buf == 0.
+ */
+ int32_t bufPos;
+
+public:
+ /**
+ * Value returned when there are no more characters to iterate.
+ */
+ enum { DONE = -1 };
+
+ /**
+ * Bitmask option to enable parsing of variable names. If (options &
+ * PARSE_VARIABLES) != 0, then an embedded variable will be expanded to
+ * its value. Variables are parsed using the SymbolTable API.
+ */
+ enum { PARSE_VARIABLES = 1 };
+
+ /**
+ * Bitmask option to enable parsing of escape sequences. If (options &
+ * PARSE_ESCAPES) != 0, then an embedded escape sequence will be expanded
+ * to its value. Escapes are parsed using Utility.unescapeAt().
+ */
+ enum { PARSE_ESCAPES = 2 };
+
+ /**
+ * Bitmask option to enable skipping of whitespace. If (options &
+ * SKIP_WHITESPACE) != 0, then whitespace characters will be silently
+ * skipped, as if they were not present in the input. Whitespace
+ * characters are defined by UCharacterProperty.isRuleWhiteSpace().
+ */
+ enum { SKIP_WHITESPACE = 4 };
+
+ /**
+ * Constructs an iterator over the given text, starting at the given
+ * position.
+ * @param text the text to be iterated
+ * @param sym the symbol table, or null if there is none. If sym is null,
+ * then variables will not be deferenced, even if the PARSE_VARIABLES
+ * option is set.
+ * @param pos upon input, the index of the next character to return. If a
+ * variable has been dereferenced, then pos will <em>not</em> increment as
+ * characters of the variable value are iterated.
+ */
+ RuleCharacterIterator(const UnicodeString& text, const SymbolTable* sym,
+ ParsePosition& pos);
+
+ /**
+ * Returns true if this iterator has no more characters to return.
+ */
+ UBool atEnd() const;
+
+ /**
+ * Returns the next character using the given options, or DONE if there
+ * are no more characters, and advance the position to the next
+ * character.
+ * @param options one or more of the following options, bitwise-OR-ed
+ * together: PARSE_VARIABLES, PARSE_ESCAPES, SKIP_WHITESPACE.
+ * @param isEscaped output parameter set to TRUE if the character
+ * was escaped
+ * @param ec input-output error code. An error will only be set by
+ * this routing if options includes PARSE_VARIABLES and an unknown
+ * variable name is seen, or if options includes PARSE_ESCAPES and
+ * an invalid escape sequence is seen.
+ * @return the current 32-bit code point, or DONE
+ */
+ UChar32 next(int32_t options, UBool& isEscaped, UErrorCode& ec);
+
+ /**
+ * Returns true if this iterator is currently within a variable expansion.
+ */
+ inline UBool inVariable() const;
+
+ /**
+ * An opaque object representing the position of a RuleCharacterIterator.
+ */
+ struct Pos {
+ private:
+ const UnicodeString* buf;
+ int32_t pos;
+ int32_t bufPos;
+ friend class RuleCharacterIterator;
+ };
+
+ /**
+ * Sets an object which, when later passed to setPos(), will
+ * restore this iterator's position. Usage idiom:
+ *
+ * RuleCharacterIterator iterator = ...;
+ * RuleCharacterIterator::Pos pos;
+ * iterator.getPos(pos);
+ * for (;;) {
+ * iterator.getPos(pos);
+ * int c = iterator.next(...);
+ * ...
+ * }
+ * iterator.setPos(pos);
+ *
+ * @param p a position object to be set to this iterator's
+ * current position.
+ */
+ void getPos(Pos& p) const;
+
+ /**
+ * Restores this iterator to the position it had when getPos()
+ * set the given object.
+ * @param p a position object previously set by getPos()
+ */
+ void setPos(const Pos& p);
+
+ /**
+ * Skips ahead past any ignored characters, as indicated by the given
+ * options. This is useful in conjunction with the lookahead() method.
+ *
+ * Currently, this only has an effect for SKIP_WHITESPACE.
+ * @param options one or more of the following options, bitwise-OR-ed
+ * together: PARSE_VARIABLES, PARSE_ESCAPES, SKIP_WHITESPACE.
+ */
+ void skipIgnored(int32_t options);
+
+ /**
+ * Returns a string containing the remainder of the characters to be
+ * returned by this iterator, without any option processing. If the
+ * iterator is currently within a variable expansion, this will only
+ * extend to the end of the variable expansion. This method is provided
+ * so that iterators may interoperate with string-based APIs. The typical
+ * sequence of calls is to call skipIgnored(), then call lookahead(), then
+ * parse the string returned by lookahead(), then call jumpahead() to
+ * resynchronize the iterator.
+ * @param result a string to receive the characters to be returned
+ * by future calls to next()
+ * @return a reference to result
+ */
+ UnicodeString& lookahead(UnicodeString& result) const;
+
+ /**
+ * Advances the position by the given number of 16-bit code units.
+ * This is useful in conjunction with the lookahead() method.
+ * @param count the number of 16-bit code units to jump over
+ */
+ void jumpahead(int32_t count);
+
+ /**
+ * Returns a string representation of this object, consisting of the
+ * characters being iterated, with a '|' marking the current position.
+ * Position within an expanded variable is <em>not</em> indicated.
+ * @param result output parameter to receive a string
+ * representation of this object
+ */
+// UnicodeString& toString(UnicodeString& result) const;
+
+private:
+ /**
+ * Returns the current 32-bit code point without parsing escapes, parsing
+ * variables, or skipping whitespace.
+ * @return the current 32-bit code point
+ */
+ UChar32 _current() const;
+
+ /**
+ * Advances the position by the given amount.
+ * @param count the number of 16-bit code units to advance past
+ */
+ void _advance(int32_t count);
+};
+
+inline UBool RuleCharacterIterator::inVariable() const {
+ return buf != 0;
+}
+
+U_NAMESPACE_END
+
+#endif // _RULEITER_H_
+//eof