source: other-projects/trunk/anttasks/src/org/greenstone/anttasks/SplitResource.java@ 17089

/*
 *    SplitResource.java
 *    A task to split a file into chunks and optionally add references to those
 *    chunks in an rc (resource compiler) script
 *
 *    Copyright (C) 2005 New Zealand Digital Library, http://www.nzdl.org
 *
 *    This program 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.
 *
 *    This program 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 General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

package org.greenstone.anttasks;

import org.apache.tools.ant.*;
import org.apache.tools.ant.taskdefs.*;
import java.util.*;
import java.io.*;
import java.util.regex.*;

/**
 * Splits a file (resource) into chunks of a given size and puts them in files 
 * with the same name as the resource but appended with a dot followed by the chunk number
 */
public class SplitResource extends Task {

    private File resource = null;
    private File resourceScript = null;
    private File outputDir = null;
    private String resourceName = null;
    private String resourceType = null;
    private int chunkSize = 0;
    

    /**
     * for testing
     */
    public static void main( String[] args ) {

        SplitResource sr = new SplitResource();
        sr.setResource( new File(args[0]) );
        sr.setOutputDir( new File(args[1]) );
        sr.setResourceScript( new File(args[2]) );
        sr.setResourceName( args[3] );
        sr.setResourceType( args[4] );
        sr.setChunkSize( Integer.parseInt(args[5]) );
        sr.execute();

    }

    public void execute() {

        if ( resource == null ) {
            throw new BuildException( "Error - No resource specified !!" );
        }

        if ( outputDir == null ) {
            outputDir = new File(".");
        }
        outputDir.mkdir();

        if ( chunkSize == 0 ) {
            throw new BuildException( "Error - No chunk size specified !!" );
        }

        DataInputStream is;

        try {
            is = new DataInputStream( new FileInputStream( resource ) );
        } catch ( IOException e ) {
            throw new BuildException( "Error - couldn't open the resource file" );
        }

        //figure out how many chunks to do this in
        int noChunks = (int)(resource.length() / chunkSize) + 1;

        System.out.println( "Splitting file into chunks" );
        System.out.println( "file: " + resource.getAbsolutePath() );
        System.out.println( "file size: " + resource.length() );
        System.out.println( "chunk size: " + chunkSize );
        System.out.println( "ergo, num chunks: " + noChunks );

        long written = 0;
        for ( int i=0; i<noChunks; i++  ) {

            //open a file for output
            DataOutputStream os;
            File partFile = new File( outputDir, resource.getName() + "." + i );
            //System.out.println( "partFile: " + partFile );

            try {
                os = new DataOutputStream( new FileOutputStream( partFile ) );
            } catch ( IOException e ) {
                throw new BuildException( "Error - couldn't create a part file" );
            }


            //sort out thisChunkSize
            int thisChunkSize = chunkSize;
            if ( i == noChunks - 1 ) {
                //System.out.println( "(Last Chunk)");
                thisChunkSize = (int)(resource.length() % chunkSize);
            }

            //System.out.println( "Read a chunk (" + thisChunkSize + " bytes)" );
            byte[] data = new byte[thisChunkSize];
            try {
                is.readFully( data, 0, thisChunkSize );
            } catch( EOFException eof ) {
                throw new BuildException( "Error - unexpectedly hit the end of the resource file" );
            } catch ( IOException e ) {
                throw new BuildException( "Error - couldn't read a byte from the resource file" );
            }

            //System.out.println( "Write to the file");
            try {
                os.write( data, 0, thisChunkSize );
                written += thisChunkSize;
            } catch ( IOException e ) {
                throw new BuildException( "Error - couldn't write out a byte to the part file" );
            }

            try {
                os.close();
            } catch ( IOException e ) {
                throw new BuildException( "Error - couldn't close a chunk output stream" );
            }
      }
        
        //System.out.println( "Total written: " + written + " bytes" );

        try {
          is.close();
        } catch ( IOException e ) {
            throw new BuildException( "Error - couldn't close the input stream" );
        }


        //if they have specified a resource script and resource name, write an rc file
        if ( resourceScript != null && resourceName != null && resourceType != null ) {
            System.out.println( "Putting references into a resource script" );
            System.out.println( "resourceScript: " + resourceScript.getAbsolutePath() );
            System.out.println( "resourceName  : " + resourceName );
            System.out.println( "resourceType  : " + resourceType );
            
            //open the resource script
            PrintWriter out = null;
            try {
                out = new PrintWriter(new FileWriter( resourceScript, true ));
            } catch ( IOException e ) {
                throw new BuildException( "Error - couldn't open the resource script" );
            }

            //put a line in for each chunk
            for ( int i=0; i<noChunks; i++ ){
                out.println(
                    resourceName + "_" + (i+1) + " " + resourceType + " \"" + resource.getName() + "." + i + "\""
                    );
            }
            
            //close the resource script
           out.close();
        }
    }

   
    public void setResource(File resource) {
        this.resource = resource;
    }

    public void setResourceScript(File resourceScript) {
        this.resourceScript = resourceScript;
    }

    public void setResourceName(String resourceName) {
        this.resourceName = resourceName;
    }
    public void setResourceType(String resourceType) {
        this.resourceType = resourceType;
    }

    public void setOutputDir(File outputDir) {
        this.outputDir = outputDir;
    }

    public void setChunkSize(int chunkSize) {
        this.chunkSize = chunkSize;
    }

}