gcc/libjava/gnu/gcj/text/CharacterBreakIterator.java
2000-01-19 18:39:27 +00:00

189 lines
4.5 KiB
Java

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