/*
* Minecraft Forge
* Copyright (c) 2016.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation version 2.1
* of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
package net.minecraftforge.fml.repackage.com.nothome.delta;
import org.apache.commons.io.IOUtils;
import static net.minecraftforge.fml.repackage.com.nothome.delta.GDiffWriter.COPY_INT_INT;
import static net.minecraftforge.fml.repackage.com.nothome.delta.GDiffWriter.COPY_INT_UBYTE;
import static net.minecraftforge.fml.repackage.com.nothome.delta.GDiffWriter.COPY_INT_USHORT;
import static net.minecraftforge.fml.repackage.com.nothome.delta.GDiffWriter.COPY_LONG_INT;
import static net.minecraftforge.fml.repackage.com.nothome.delta.GDiffWriter.COPY_USHORT_INT;
import static net.minecraftforge.fml.repackage.com.nothome.delta.GDiffWriter.COPY_USHORT_UBYTE;
import static net.minecraftforge.fml.repackage.com.nothome.delta.GDiffWriter.COPY_USHORT_USHORT;
import static net.minecraftforge.fml.repackage.com.nothome.delta.GDiffWriter.DATA_INT;
import static net.minecraftforge.fml.repackage.com.nothome.delta.GDiffWriter.DATA_MAX;
import static net.minecraftforge.fml.repackage.com.nothome.delta.GDiffWriter.DATA_USHORT;
import static net.minecraftforge.fml.repackage.com.nothome.delta.GDiffWriter.EOF;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.EOFException;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
/**
* This class patches an input file with a GDIFF patch file.
*
* The patch file follows the GDIFF file specification available at
*
* <a href="http://www.w3.org/TR/NOTE-gdiff-19970901.html">http://www.w3.org/TR/NOTE-gdiff-19970901.html</a>.
*/
public class GDiffPatcher {
private ByteBuffer buf = ByteBuffer.allocate(1024);
private byte buf2[] = buf.array();
/**
* Constructs a new GDiffPatcher.
*/
public GDiffPatcher() {
}
/**
* Patches to an output file.
*/
public void patch(File sourceFile, File patchFile, File outputFile)
throws IOException
{
RandomAccessFileSeekableSource source =new RandomAccessFileSeekableSource(new RandomAccessFile(sourceFile, "r"));
InputStream patch = null;
OutputStream output = null;
try {
patch = new FileInputStream(patchFile);
output = new FileOutputStream(outputFile);
patch(source, patch, output);
} finally {
IOUtils.closeQuietly(source);
IOUtils.closeQuietly(patch);
IOUtils.closeQuietly(output);
}
}
/**
* Patches to an output stream.
*/
public void patch(byte[] source, InputStream patch, OutputStream output) throws IOException {
patch(new ByteBufferSeekableSource(source), patch, output);
}
/**
* Patches in memory, returning the patch result.
*/
public byte[] patch(byte[] source, byte[] patch) throws IOException {
ByteArrayOutputStream os = new ByteArrayOutputStream();
patch(source, new ByteArrayInputStream(patch), os);
return os.toByteArray();
}
/**
* Patches to an output stream.
*/
public void patch(SeekableSource source, InputStream patch, OutputStream out) throws IOException {
DataOutputStream outOS = new DataOutputStream(out);
DataInputStream patchIS = new DataInputStream(patch);
// the magic string is 'd1 ff d1 ff' + the version number
if (patchIS.readUnsignedByte() != 0xd1 ||
patchIS.readUnsignedByte() != 0xff ||
patchIS.readUnsignedByte() != 0xd1 ||
patchIS.readUnsignedByte() != 0xff ||
patchIS.readUnsignedByte() != 0x04) {
throw new PatchException("magic string not found, aborting!");
}
while (true) {
int command = patchIS.readUnsignedByte();
if (command == EOF)
break;
int length;
int offset;
if (command <= DATA_MAX) {
append(command, patchIS, outOS);
continue;
}
switch (command) {
case DATA_USHORT: // ushort, n bytes following; append
length = patchIS.readUnsignedShort();
append(length, patchIS, outOS);
break;
case DATA_INT: // int, n bytes following; append
length = patchIS.readInt();
append(length, patchIS, outOS);
break;
case COPY_USHORT_UBYTE:
offset = patchIS.readUnsignedShort();
length = patchIS.readUnsignedByte();
copy(offset, length, source, outOS);
break;
case COPY_USHORT_USHORT:
offset = patchIS.readUnsignedShort();
length = patchIS.readUnsignedShort();
copy(offset, length, source, outOS);
break;
case COPY_USHORT_INT:
offset = patchIS.readUnsignedShort();
length = patchIS.readInt();
copy(offset, length, source, outOS);
break;
case COPY_INT_UBYTE:
offset = patchIS.readInt();
length = patchIS.readUnsignedByte();
copy(offset, length, source, outOS);
break;
case COPY_INT_USHORT:
offset = patchIS.readInt();
length = patchIS.readUnsignedShort();
copy(offset, length, source, outOS);
break;
case COPY_INT_INT:
offset = patchIS.readInt();
length = patchIS.readInt();
copy(offset, length, source, outOS);
break;
case COPY_LONG_INT:
long loffset = patchIS.readLong();
length = patchIS.readInt();
copy(loffset, length, source, outOS);
break;
default:
throw new IllegalStateException("command " + command);
}
}
outOS.flush();
}
private void copy(long offset, int length, SeekableSource source, OutputStream output)
throws IOException
{
source.seek(offset);
while (length > 0) {
int len = Math.min(buf.capacity(), length);
buf.clear().limit(len);
int res = source.read(buf);
if (res == -1)
throw new EOFException("in copy " + offset + " " + length);
output.write(buf.array(), 0, res);
length -= res;
}
}
private void append(int length, InputStream patch, OutputStream output) throws IOException {
while (length > 0) {
int len = Math.min(buf2.length, length);
int res = patch.read(buf2, 0, len);
if (res == -1)
throw new EOFException("cannot read " + length);
output.write(buf2, 0, res);
length -= res;
}
}
/**
* Simple command line tool to patch a file.
*/
public static void main(String argv[]) {
if (argv.length != 3) {
System.err.println("usage GDiffPatch source patch output");
System.err.println("aborting..");
return;
}
try {
File sourceFile = new File(argv[0]);
File patchFile = new File(argv[1]);
File outputFile = new File(argv[2]);
if (sourceFile.length() > Integer.MAX_VALUE ||
patchFile.length() > Integer.MAX_VALUE) {
System.err.println("source or patch is too large, max length is " + Integer.MAX_VALUE);
System.err.println("aborting..");
return;
}
GDiffPatcher patcher = new GDiffPatcher();
patcher.patch(sourceFile, patchFile, outputFile);
System.out.println("finished patching file");
} catch (Exception ioe) { //gls031504a
System.err.println("error while patching: " + ioe);
}
}
}