fileadapter.java

用java实现的神经网络bp的核心算法

/*
 * FileAdapter.java
 *
 * Created on 2007骞?1鏈?3鏃? 2:47
 *
 * To change this template, choose Tools | Template Manager
 * and open the template infile the editor.
 */

package Compressor;
import java.io.*;
import java.util.*;
/**
 * file adapter will normalize binary code to numbers in the range between 0.1 * Range and 0.9 * Range.
 * Or translate back.
 * @author yuhui_bear
 */
public class FileAdapter {
    private BufferedInputStream infile;
    private BufferedOutputStream outfile;
    private long groupSize;
    private long filelength;
    private long orglength;
    private int dividedSize;
//    private int writeCnt=0;
    private final int VALUE =4;
    private double Range =1 * 0.8D;
    private double BASE = 1 * 0.1258D;
    private double enDIF = Range / VALUE;
    private double deDIF = Range / (VALUE *2 );
    private int BIT=2;
    /**
     * Creates a new instance of FileAdapter
     * @param inf work file.
     * @param ds the size of data array.
     * @param encode TRUE ,work in encoding mode.
     * FALSE, work in decoding mode.
     * @throws java.io.IOException If IOException encountered ,IOException was thrown.
     */
    public FileAdapter(File inf , int ds ,boolean encode) throws IOException{
        dividedSize = ds;
        String path = inf.getPath().substring(0 , inf.getPath().length()-inf.getName().length());
        infile = new BufferedInputStream(new FileInputStream(inf));
        //write length of the original file.
        if(encode){
            filelength = inf.length(); 
            outfile =new BufferedOutputStream(new FileOutputStream(new File(path,inf.getName().replaceAll("\\.\\w{1,3}",".nc"))));
            DataOutputStream tout =new DataOutputStream(outfile);
            tout.writeUTF(inf.getName());
            tout.writeLong(filelength);
            orglength = filelength / BIT;
            if(filelength %2 !=0){
                orglength ++;
            }
        }else{
            //decode.
            DataInputStream tin =new DataInputStream(infile);
            String outname = tin.readUTF();
            orglength = tin.readLong();
            filelength = inf.length()- 8 -2- outname.length(); 
            outfile =new BufferedOutputStream(new FileOutputStream(new File(path,outname)));            
        }
        if(dividedSize == 4){
            groupSize=filelength ;
        }else{
            groupSize=(long)((double)filelength / (double)dividedSize / 4D) +1;
        }
    }

    /**
     * get numbers of group.
     * @return how many group the source data divided to.
     */
    public long getGroupSize(){
        return groupSize;
    }
    /**
     * get next group values needed to encode or decode.
     * @return ,an array of adjusted values.
     */
    public double[] nextGroup(){
        double[] source = new double[dividedSize];
        Arrays.fill(source,-1);
        int cnt=0;
        
        try {
            for(int i = 0;i<dividedSize;i +=4){
                cnt = infile.read();
                //reach end of the file.
                 filelength --; 
                if( filelength <0){
                        infile.close();
                        return source;
                }
                source[i]=cnt;          //highest 2 bites.
                source[i+1]=cnt;        
                source[i+2]=cnt;        //lowest 2 bites.
                source[i+3]=cnt;
                source[i] = (((int)source[i] >>>6 & 0x00000003))* enDIF + BASE;
                source[i+1] = (((int)source[i+1] >>>4& 0x00000003))* enDIF + BASE;
                source[i+2] = (((int)source[i+2] >>>2& 0x00000003))* enDIF + BASE;
                source[i+3] = (((int)source[i+3] & 0x00000003))* enDIF + BASE;
            }
        } catch (IOException ex) {
//            ex.printStackTrace();
            return null;
        }             
        return source;
    }
    /**
     * get next byte value.
     * @return next byte.
     */
    public int nextByte(){
        int source =0;      
        try {
            for(int i = 0;i<dividedSize;i++){
                source =infile.read();
                //reach end of the file.
                if( source <0){
                        infile.close();
                        return -1;
                }
            }
        } catch (IOException ex) {            
            ex.printStackTrace();
            return -1;
        }             
        return source;
    }
    /**
     * write encoded or decoded data to file.
     * @param ind , data to write between 0.1 * Range ~ 0.9 * Range.
     * @return ,if succeed 0, error -1,IOException -2.
     */
    public int writeBack(double[] ind){        
        if(ind ==null){
            try {
                outfile.close();
            } catch (IOException ex) {
                ex.printStackTrace();
                return -1;
            }
            return 1;
        }else{
            if(ind.length % 4 == 0){
                try {
//                    if(writeCnt !=0){
                        //low 4 bites gained.write back.
//                        for (int id =0;id<ind.length;id +=2){
                        orglength -= ind.length / 4;
                        for(int iw =0;iw < ind.length / 4;iw++){
                            outfile.write(((int)(((ind[iw + 3] - BASE)/ deDIF +1)/2 ) <<2 & 0x000000C0)          //lowest bit.
                                            | ((int)(((ind[iw + 2] - BASE)/ deDIF +1)/2 ) & 0x00000030)
                                            | ((int)(((ind[iw + 1] - BASE)/ deDIF +1)/2 ) <<6 & 0x000000C0)
                                            | ((int)(((ind[iw] - BASE)/ deDIF +1)/2 ) << 4 & 0x00000030));   //highest bit.
                        }
//                        writeCnt=0;
                        if(orglength <1){
                            try {
                                outfile.close();
                            } catch (IOException ex) {
                                ex.printStackTrace();
                                return -1;
                            }
                            return 2;
                        }                    
//                        }//for end.
//                    }else{
                        //store high 4 bites.
//                        writeCnt=((int)(((ind[0] - BASE)/ deDIF +1)/2 ) <<6 & 0x000000C0) | ((int)(((ind[1] - BASE)/ deDIF +1)/2 ) << 4 & 0x00000030);
//                    }
                } catch (IOException ex) {
                    ex.printStackTrace();
                    return -2;
                }
            }else{
                return -1;
            }
        }
        return 1;
    }
    
}