brouter/brouter-mapaccess/src/main/java/btools/mapaccess/Rd5DiffManager.java

129 lines
3.5 KiB
Java

/**
* Manage rd5 diff-file creation
*
* @author ab
*/
package btools.mapaccess;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.security.DigestInputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
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 + ".df5";
File diffFile = new File( specificNewDiffs, diffFileName );
String dummyDiffFileName = md5New + ".df5";
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( ".df5" ) )
{
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 IOException
{
try {
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();
} catch (NoSuchAlgorithmException e) {
throw new IOException("MD5 algorithm not available", e);
}
}
private static char hexChar( int v )
{
return (char) ( v > 9 ? 'a' + (v-10) : '0' + v );
}
}