126 lines
3.3 KiB
Java
126 lines
3.3 KiB
Java
/**
|
|
* Proof of concept for delta rd5's
|
|
*
|
|
* @author ab
|
|
*/
|
|
package btools.mapaccess;
|
|
|
|
import java.io.BufferedInputStream;
|
|
import java.io.File;
|
|
import java.io.FileInputStream;
|
|
import java.security.DigestInputStream;
|
|
import java.security.MessageDigest;
|
|
|
|
final public class Rd5DiffManager
|
|
{
|
|
public static void main( String[] args ) throws Exception
|
|
{
|
|
calcDiffs( new File( args[0] ),new File( args[1] ) );
|
|
}
|
|
|
|
/**
|
|
* Compute diffs for all RD5 files
|
|
*/
|
|
public static void calcDiffs( File oldDir, File newDir ) throws Exception
|
|
{
|
|
File oldDiffDir = new File( oldDir, "diff" );
|
|
File newDiffDir = new File( newDir, "diff" );
|
|
|
|
File[] filesNew = newDir.listFiles();
|
|
|
|
for( File fn : filesNew )
|
|
{
|
|
String name = fn.getName();
|
|
if ( !name.endsWith( ".rd5" ) )
|
|
{
|
|
continue;
|
|
}
|
|
if ( fn.length() < 1024*1024 )
|
|
{
|
|
continue; // exclude very small files from diffing
|
|
}
|
|
String basename = name.substring( 0, name.length() - 4 );
|
|
File fo = new File( oldDir, name );
|
|
if ( !fo.isFile() )
|
|
{
|
|
continue;
|
|
}
|
|
|
|
// calculate MD5 of old file
|
|
String md5 = getMD5( fo );
|
|
|
|
String md5New = getMD5( fn );
|
|
|
|
System.out.println( "name=" + name + " md5=" + md5 );
|
|
|
|
File specificNewDiffs = new File( newDiffDir, basename );
|
|
specificNewDiffs.mkdirs();
|
|
|
|
String diffFileName = md5 + ".rd5diff";
|
|
File diffFile = new File( specificNewDiffs, diffFileName );
|
|
|
|
String dummyDiffFileName = md5New + ".rd5diff";
|
|
File dummyDiffFile = new File( specificNewDiffs, dummyDiffFileName );
|
|
dummyDiffFile.createNewFile();
|
|
|
|
// calc the new diff
|
|
Rd5DiffTool.diff2files( fo, fn, diffFile );
|
|
|
|
// ... and add that to old diff files
|
|
File specificOldDiffs = new File( oldDiffDir, basename );
|
|
if ( specificOldDiffs.isDirectory() )
|
|
{
|
|
File[] oldDiffs = specificOldDiffs.listFiles();
|
|
for( File od : oldDiffs )
|
|
{
|
|
if ( !od.getName().endsWith( ".rd5diff" ) )
|
|
{
|
|
continue;
|
|
}
|
|
if ( System.currentTimeMillis() - od.lastModified() > 9*86400000L )
|
|
{
|
|
continue; // limit diff history to 9 days
|
|
}
|
|
|
|
File updatedDiff = new File( specificNewDiffs, od.getName() );
|
|
if ( !updatedDiff.exists() )
|
|
{
|
|
Rd5DiffTool.addDeltas( od, diffFile, updatedDiff );
|
|
updatedDiff.setLastModified( od.lastModified() );
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
public static String getMD5( File f ) throws Exception
|
|
{
|
|
MessageDigest md = MessageDigest.getInstance("MD5");
|
|
BufferedInputStream bis = new BufferedInputStream( new FileInputStream( f ) );
|
|
DigestInputStream dis = new DigestInputStream(bis, md);
|
|
byte[] buf = new byte[8192];
|
|
for(;;)
|
|
{
|
|
int len = dis.read( buf );
|
|
if ( len <= 0 )
|
|
{
|
|
break;
|
|
}
|
|
}
|
|
dis.close();
|
|
byte[] bytes = md.digest();
|
|
|
|
StringBuilder sb = new StringBuilder();
|
|
for (int j = 0; j < bytes.length; j++)
|
|
{
|
|
int v = bytes[j] & 0xff;
|
|
sb.append( hexChar( v >>> 4 ) ).append( hexChar( v & 0xf ) );
|
|
}
|
|
return sb.toString();
|
|
}
|
|
|
|
private static char hexChar( int v )
|
|
{
|
|
return (char) ( v > 9 ? 'a' + (v-10) : '0' + v );
|
|
}
|
|
}
|