/*
* ====================================================================
*
* The Apache Software License, Version 1.1
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* modification, are permitted provided that the following conditions
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* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowledgement:
* "This product includes software developed by the
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*
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package org.apache.commons.jrcs.diff;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
/**
* Holds a information about a parrt of the text involved in
* a differencing or patching operation.
*
* @version $Id: Chunk.java 2891 2005-10-25 17:30:31Z ian@caret.cam.ac.uk $
* @author <a href="mailto:juanco@suigeneris.org">Juanco Anez</a>
* @see Diff
* @see Delta
*/
public class Chunk
extends org.apache.commons.jrcs.util.ToString
{
protected int anchor;
protected int count;
protected List chunk;
/**
* Creates a chunk that doesn't copy the original text.
* @param pos the start position in the text.
* @param count the size of the chunk.
*/
public Chunk(int pos, int count)
{
this.anchor = pos;
this.count = (count >= 0 ? count : 0);
}
/**
* Creates a chunk and saves a copy the original chunk's text.
* @param iseq the original text.
* @param pos the start position in the text.
* @param count the size of the chunk.
*/
public Chunk(Object[] iseq, int pos, int count)
{
this(pos, count);
chunk = slice(iseq, pos, count);
}
/**
* Creates a chunk that will be displaced in the resulting text,
* and saves a copy the original chunk's text.
* @param iseq the original text.
* @param pos the start position in the text.
* @param count the size of the chunk.
* @param offset the position the chunk should have in the resulting text.
*/
public Chunk(Object[] iseq, int pos, int count, int offset)
{
this(offset, count);
chunk = slice(iseq, pos, count);
}
/**
* Creates a chunk and saves a copy the original chunk's text.
* @param iseq the original text.
* @param pos the start position in the text.
* @param count the size of the chunk.
*/
public Chunk(List iseq, int pos, int count)
{
this(pos, count);
chunk = slice(iseq, pos, count);
}
/**
* Creates a chunk that will be displaced in the resulting text,
* and saves a copy the original chunk's text.
* @param iseq the original text.
* @param pos the start position in the text.
* @param count the size of the chunk.
* @param offset the position the chunk should have in the resulting text.
*/
public Chunk(List iseq, int pos, int count, int offset)
{
this(offset, count);
chunk = slice(iseq, pos, count);
}
/**
* Returns the anchor position of the chunk.
* @return the anchor position.
*/
public int anchor()
{
return anchor;
}
/**
* Returns the size of the chunk.
* @return the size.
*/
public int size()
{
return count;
}
/**
* Returns the index of the first line of the chunk.
*/
public int first()
{
return anchor();
}
/**
* Returns the index of the last line of the chunk.
*/
public int last()
{
return anchor() + size() - 1;
}
/**
* Returns the <i>from</i> index of the chunk in RCS terms.
*/
public int rcsfrom()
{
return anchor + 1;
}
/**
* Returns the <i>to</i> index of the chunk in RCS terms.
*/
public int rcsto()
{
return anchor + count;
}
/**
* Returns the text saved for this chunk.
* @return the text.
*/
public List chunk()
{
return chunk;
}
/**
* Verifies that this chunk's saved text matches the corresponding
* text in the given sequence.
* @param target the sequence to verify against.
* @return true if the texts match.
*/
public boolean verify(List target)
{
if (chunk == null)
{
return true;
}
if (last() > target.size())
{
return false;
}
for (int i = 0; i < count; i++)
{
if (!target.get(anchor + i).equals(chunk.get(i)))
{
return false;
}
}
return true;
}
/**
* Delete this chunk from he given text.
* @param target the text to delete from.
*/
public void applyDelete(List target)
{
for (int i = last(); i >= first(); i--)
{
target.remove(i);
}
}
/**
* Add the text of this chunk to the target at the given position.
* @param start where to add the text.
* @param target the text to add to.
*/
public void applyAdd(int start, List target)
{
Iterator i = chunk.iterator();
while (i.hasNext())
{
target.add(start++, i.next());
}
}
/**
* Provide a string image of the chunk using the an empty prefix and
* postfix.
*/
public void toString(StringBuffer s)
{
toString(s, "", "");
}
/**
* Provide a string image of the chunk using the given prefix and
* postfix.
* @param s where the string image should be appended.
* @param prefix the text thatshould prefix each line.
* @param postfix the text that should end each line.
*/
public StringBuffer toString(StringBuffer s, String prefix, String postfix)
{
if (chunk != null)
{
Iterator i = chunk.iterator();
while (i.hasNext())
{
s.append(prefix);
s.append(i.next());
s.append(postfix);
}
}
return s;
}
/**
* Retreives the specified part from a {@link List List}.
* @param seq the list to retreive a slice from.
* @param pos the start position.
* @param count the number of items in the slice.
* @return a {@link List List} containing the specified items.
*/
public static List slice(List seq, int pos, int count)
{
if (count <= 0)
{
return new ArrayList(seq.subList(pos, pos));
}
else
{
return new ArrayList(seq.subList(pos, pos + count));
}
}
/**
* Retrieves a slice from an {@link Object Object} array.
* @param seq the list to retreive a slice from.
* @param pos the start position.
* @param count the number of items in the slice.
* @return a {@link List List} containing the specified items.
*/
public static List slice(Object[] seq, int pos, int count)
{
return slice(Arrays.asList(seq), pos, count);
}
/**
* Provide a string representation of the numeric range of this chunk.
*/
public String rangeString()
{
StringBuffer result = new StringBuffer();
rangeString(result);
return result.toString();
}
/**
* Provide a string representation of the numeric range of this chunk.
* @param s where the string representation should be appended.
*/
public void rangeString(StringBuffer s)
{
rangeString(s, ",");
}
/**
* Provide a string representation of the numeric range of this chunk.
* @param s where the string representation should be appended.
* @param separ what to use as line separator.
*/
public void rangeString(StringBuffer s, String separ)
{
if (size() <= 1)
{
s.append(Integer.toString(rcsfrom()));
}
else
{
s.append(Integer.toString(rcsfrom()));
s.append(separ);
s.append(Integer.toString(rcsto()));
}
}
}