Jskad/source/org/thdl/util/javaxdelta/GDiffWriter.java

141 lines
4.7 KiB
Java

/* Taken from the javaxdelta project.
http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/javaxdelta/javaxdelta/com/nothome/delta/GDiffWriter.java?rev=1.1.1.1&content-type=text/vnd.viewcvs-markup */
/*
*
* Copyright (c) 2001 Torgeir Veimo
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
*/
package org.thdl.util.javaxdelta;
/**
* The output follows the GDIFF file specification available at
* http://www.w3.org/TR/NOTE-gdiff-19970901.html.
*/
import java.util.*;
import java.io.*;
public class GDiffWriter implements DiffWriter {
byte buf[] = new byte[256]; int buflen = 0;
protected boolean debug = false;
//Vector writeQueue = new Vector();
DataOutputStream output = null;
public GDiffWriter(DataOutputStream os) throws IOException {
this.output = os;
// write magic string "d1 ff d1 ff 04"
output.writeByte(0xd1);
output.writeByte(0xff);
output.writeByte(0xd1);
output.writeByte(0xff);
output.writeByte(0x04);
}
public void setDebug(boolean flag) { debug = flag; }
public void addCopy(int offset, int length) throws IOException {
if (buflen > 0)
writeBuf();
//output debug data
if (debug)
System.err.println("COPY off: " + offset + ", len: " + length);
// output real data
byte command;
if (offset > Integer.MAX_VALUE) {
// use long, int format
output.writeByte(255);
// Actually, we don't support longer files than int.MAX_VALUE at the moment..
} else if (offset < 65536) {
if (length < 256) {
// use ushort, ubyte
output.writeByte(249);
output.writeShort(offset);
output.writeByte(length);
} else if (length > 65535) {
// use ushort, int
output.writeByte(251);
output.writeShort(offset);
output.writeInt(length);
} else {
// use ushort, ushort
output.writeByte(250);
output.writeShort(offset);
output.writeShort(length);
}
} else {
if (length < 256) {
// use int, ubyte
output.writeByte(252);
output.writeInt(offset);
output.writeByte(length);
} else if (length > 65535) {
// use int, int
output.writeByte(254);
output.writeInt(offset);
output.writeInt(length);
} else {
// use int, ushort
output.writeByte(253);
output.writeInt(offset);
output.writeShort(length);
}
}
}
public void addData(byte b) throws IOException {
if (buflen >= 246)
writeBuf();
buf[buflen] = b; buflen++;
}
private void writeBuf() throws IOException {
// output debug data
if (debug) {
System.err.print("DATA:");
for (int ix = 0; ix < buflen; ix++) {
if (buf[ix] == '\n')
System.err.print("\\n");
else
System.err.print(String.valueOf((char)((char) buf[ix])));
}
System.err.println("");
}
if (buflen > 0) {
// output real data
output.writeByte(buflen);
output.write(buf, 0, buflen);
}
buflen = 0;
}
public void flush() throws IOException { if (buflen > 0) writeBuf(); output.flush(); }
public void close() throws IOException { this.flush(); }
}