1999-04-07 22:42:40 +08:00
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// Default character BreakIterator.
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2000-01-20 02:39:27 +08:00
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/* Copyright (C) 1999 Red Hat, Inc.
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1999-04-07 22:42:40 +08:00
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This file is part of libgcj.
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This software is copyrighted work licensed under the terms of the
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Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
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details. */
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package gnu.gcj.text;
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import java.text.BreakIterator;
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import java.text.CharacterIterator;
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/**
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* @author Tom Tromey <tromey@cygnus.com>
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* @date March 19, 1999
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* Written using The Unicode Standard, Version 2.0.
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*/
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public class CharacterBreakIterator extends BaseBreakIterator
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{
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// Hangul Jamo constants from Unicode book.
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private static final int LBase = 0x1100;
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private static final int VBase = 0x1161;
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private static final int TBase = 0x11a7;
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private static final int LCount = 19;
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private static final int VCount = 21;
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private static final int TCount = 28;
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// Information about surrogates.
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private static final int highSurrogateStart = 0xD800;
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private static final int highSurrogateEnd = 0xDBFF;
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private static final int lowSurrogateStart = 0xDC00;
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private static final int lowSurrogateEnd = 0xDFFF;
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public Object clone ()
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{
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return new CharacterBreakIterator (this);
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}
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public CharacterBreakIterator ()
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{
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iter = null; // FIXME?
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}
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private CharacterBreakIterator (CharacterBreakIterator other)
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{
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iter = (CharacterIterator) other.iter.clone();
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}
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// Some methods to tell us different properties of characters.
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private final boolean isL (char c)
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{
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return c >= LBase && c <= LBase + LCount;
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}
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private final boolean isV (char c)
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{
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return c >= VBase && c <= VBase + VCount;
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}
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private final boolean isT (char c)
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{
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return c >= TBase && c <= TBase + TCount;
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}
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private final boolean isLVT (char c)
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{
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return isL (c) || isV (c) || isT (c);
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}
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private final boolean isHighSurrogate (char c)
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{
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return c >= highSurrogateStart && c <= highSurrogateEnd;
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}
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private final boolean isLowSurrogate (char c)
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{
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return c >= lowSurrogateStart && c <= lowSurrogateEnd;
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}
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public int next ()
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{
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int end = iter.getEndIndex();
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if (iter.getIndex() == end)
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return DONE;
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char c;
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for (char prev = CharacterIterator.DONE; iter.getIndex() < end; prev = c)
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{
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c = iter.next();
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if (c == CharacterIterator.DONE)
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break;
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int type = Character.getType(c);
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// Break after paragraph separators.
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if (type == Character.PARAGRAPH_SEPARATOR)
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break;
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// Now we need some lookahead.
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char ahead = iter.next();
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iter.previous();
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if (ahead == CharacterIterator.DONE)
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break;
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int aheadType = Character.getType(ahead);
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if (aheadType != Character.NON_SPACING_MARK
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&& ! isLowSurrogate (ahead)
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&& ! isLVT (ahead))
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break;
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if (! isLVT (c) && isLVT (ahead))
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break;
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if (isL (c) && ! isLVT (ahead)
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&& aheadType != Character.NON_SPACING_MARK)
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break;
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if (isV (c) && ! isV (ahead) && !isT (ahead)
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&& aheadType != Character.NON_SPACING_MARK)
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break;
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if (isT (c) && ! isT (ahead)
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&& aheadType != Character.NON_SPACING_MARK)
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break;
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if (! isHighSurrogate (c) && isLowSurrogate (ahead))
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break;
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if (isHighSurrogate (c) && ! isLowSurrogate (ahead))
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break;
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if (! isHighSurrogate (prev) && isLowSurrogate (c))
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break;
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}
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return iter.getIndex();
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}
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public int previous ()
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{
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if (iter.getIndex() == iter.getBeginIndex())
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return DONE;
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int start = iter.getBeginIndex();
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while (iter.getIndex() >= iter.getBeginIndex())
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{
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char c = iter.previous();
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if (c == CharacterIterator.DONE)
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break;
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int type = Character.getType(c);
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if (type != Character.NON_SPACING_MARK
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&& ! isLowSurrogate (c)
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&& ! isLVT (c))
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break;
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// Now we need some lookahead.
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char ahead = iter.previous();
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if (ahead == CharacterIterator.DONE)
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{
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iter.next();
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break;
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}
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char ahead2 = iter.previous();
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iter.next();
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iter.next();
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if (ahead2 == CharacterIterator.DONE)
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break;
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int aheadType = Character.getType(ahead);
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if (aheadType == Character.PARAGRAPH_SEPARATOR)
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break;
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if (isLVT (c) && ! isLVT (ahead))
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break;
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if (! isLVT (c) && type != Character.NON_SPACING_MARK
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&& isL (ahead))
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break;
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if (! isV (c) && ! isT (c) && type != Character.NON_SPACING_MARK
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&& isV (ahead))
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break;
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if (! isT (c) && type != Character.NON_SPACING_MARK
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&& isT (ahead))
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break;
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if (isLowSurrogate (c) && ! isHighSurrogate (ahead))
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break;
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if (! isLowSurrogate (c) && isHighSurrogate (ahead))
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break;
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if (isLowSurrogate (ahead) && ! isHighSurrogate (ahead2))
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break;
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}
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return iter.getIndex();
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}
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}
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