/*
* Copyright (c) 1998-2011 Caucho Technology -- all rights reserved
*
* This file is part of Resin(R) Open Source
*
* Each copy or derived work must preserve the copyright notice and this
* notice unmodified.
*
* Resin Open Source is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* Resin Open Source 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, or any warranty
* of NON-INFRINGEMENT. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with Resin Open Source; if not, write to the
* Free SoftwareFoundation, Inc.
* 59 Temple Place, Suite 330
* Boston, MA 02111-1307 USA
*
* @author Scott Ferguson
*/
package com.caucho.util;
import com.caucho.vfs.*;
import java.io.*;
import java.util.*;
public class BinaryDiff {
int _oldLength;
ArrayList<TempBuffer> _oldBuffers;
byte[][] _oldBytes;
int _chunkSize = 1;
int _chunkCount;
int []_suffixArray;
int []_charMin;
int []_charMax;
public void delta(OutputStream out, InputStream oldFile, InputStream newFile)
throws IOException
{
readBuffers(oldFile);
processOrigFile();
processNewFile(out, newFile);
}
protected void add(OutputStream out, byte []buffer, int offset, int length)
throws IOException
{
System.out.println("ADD(" + length + "): '" + new String(buffer, offset, length) + "'");
}
protected void copy(OutputStream out, int offset, int length)
throws IOException
{
System.out.println("COPY(" + offset + "," + length + ")");
}
private void readBuffers(InputStream oldFile)
throws IOException
{
_oldBuffers = new ArrayList<TempBuffer>();
_oldLength = 0;
while (true) {
TempBuffer buf = TempBuffer.allocate();
byte []buffer = buf.getBuffer();
int sublen = readAll(oldFile, buffer);
if (sublen < 0) {
TempBuffer.free(buf);
break;
}
_oldLength += sublen;
_oldBuffers.add(buf);
if (sublen < buffer.length)
break;
}
_oldBytes = new byte[_oldBuffers.size()][];
for (int i = 0; i < _oldBytes.length; i++) {
_oldBytes[i] = _oldBuffers.get(i).getBuffer();
}
}
private void processOrigFile()
{
_chunkCount = _oldLength / _chunkSize;
_suffixArray = new int[_chunkCount];
int chunkSize = _chunkSize;
int chunkCount = _chunkCount;
int []suffixArray = _suffixArray;
for (int i = 0; i < chunkCount; i++) {
suffixArray[i] = i * chunkSize;
}
byte [][]data = _oldBytes;
sort(suffixArray, _oldBytes, TempBuffer.SIZE, _chunkSize);
int []charMin = _charMin = new int[256];
int []charMax = _charMax = new int[256];
for (int i = 0; i < suffixArray.length; i++) {
int offset = suffixArray[i];
int ch = data[offset / TempBuffer.SIZE][offset % TempBuffer.SIZE] & 0xff;
if (charMin[ch] == 0)
charMin[ch] = i;
charMax[ch] = i + 1;
}
}
private static void sort(int []suffixArray, byte [][]data,
int bufLength, int chunkSize)
{
int length = suffixArray.length;
int dataLength = length * chunkSize;
for (int i = 0; i < suffixArray.length - 1; i++) {
for (int j = suffixArray.length - 2; i <= j; j--) {
int a = suffixArray[j];
int b = suffixArray[j + 1];
if (suffixCompareTo(a, b, data, dataLength, bufLength) > 0) {
int temp = suffixArray[j];
suffixArray[j] = suffixArray[j + 1];
suffixArray[j + 1] = temp;
}
}
}
}
private static int suffixCompareTo(int a, int b, byte [][]data,
int length, int bufLength)
{
int sublen = length - a;
if (length - b < sublen)
sublen = length - b;
for (int i = 0; i < sublen; i++) {
int a1 = data[a / bufLength][a % bufLength];
int b1 = data[b / bufLength][b % bufLength];
if (a1 < b1)
return -1;
else if (b1 < a1)
return 1;
a++;
b++;
}
return 0;
}
private void processNewFile(OutputStream out, InputStream newIn)
throws IOException
{
TempBuffer tempBuf = TempBuffer.allocate();
byte []buffer = tempBuf.getBuffer();;
int length = readAll(newIn, buffer);
int prevOffset = 0;
int offset = 0;
int []charMin = _charMin;
int []charMax = _charMax;
int minLength = 8;
byte [][]data = _oldBytes;
int []suffixArray = _suffixArray;
loop:
for (; offset + minLength < length; offset += 1) {
int ch = buffer[offset] & 0xff;
int min = charMin[ch];
int max = charMax[ch];
byte ch2 = buffer[offset + 1];
for (int i = min; i < max; i++) {
int suffixOffset = suffixArray[i];
int dataOffset = suffixOffset + 1;
byte d1 = data[suffixOffset / TempBuffer.SIZE][suffixOffset % TempBuffer.SIZE];
byte d2 = data[dataOffset / TempBuffer.SIZE][dataOffset % TempBuffer.SIZE];
if (d2 == ch2) {
dataOffset++;
int bufOffset = offset + 2;
match_loop:
while (bufOffset < length && dataOffset < _oldLength) {
byte bufCh = buffer[bufOffset];
byte dataCh = data[dataOffset / TempBuffer.SIZE][dataOffset % TempBuffer.SIZE];
if (bufCh == dataCh) {
bufOffset += 1;
dataOffset += 1;
}
else if (bufCh < dataCh) {
if (dataOffset - suffixOffset >= minLength) {
if (prevOffset < offset)
add(out, buffer, prevOffset, offset - prevOffset);
offset = bufOffset;
copy(out, suffixOffset, dataOffset - suffixOffset);
prevOffset = offset;
continue loop;
}
else
break;
}
else {
for (i++; i < max; i++) {
int newSuffix = suffixArray[i];
int newOffset = newSuffix + (dataOffset - suffixOffset);
boolean isMatch = true;
for (int j = newOffset; newSuffix <= j; j--) {
dataCh = data[j / TempBuffer.SIZE][j % TempBuffer.SIZE];
bufCh = buffer[offset + (j - newSuffix)];
if (bufCh != dataCh) {
isMatch = false;
break;
}
}
if (isMatch) {
dataOffset = newOffset;
suffixOffset = newSuffix;
continue match_loop;
}
}
if (dataOffset - suffixOffset >= minLength) {
if (prevOffset < offset)
add(out, buffer, prevOffset, offset - prevOffset);
offset = bufOffset;
prevOffset = offset;
copy(out, suffixOffset, dataOffset - suffixOffset);
continue loop;
}
else
break;
}
}
if (dataOffset - suffixOffset >= minLength) {
if (prevOffset < offset)
add(out, buffer, prevOffset, offset - prevOffset);
offset = bufOffset;
prevOffset = offset;
copy(out, suffixOffset, dataOffset - suffixOffset);
}
break;
}
else if (ch2 < d2)
break;
}
}
if (prevOffset < length)
add(out, buffer, prevOffset, length - prevOffset);
TempBuffer.free(tempBuf);
}
private int readAll(InputStream is, byte []buffer)
throws IOException
{
int offset = 0;
while (offset < buffer.length) {
int sublen = buffer.length - offset;
sublen = is.read(buffer, offset, sublen);
if (sublen < 0)
return offset > 0 ? offset : -1;
offset += sublen;
}
return buffer.length;
}
}