SHA1 Sum : SHA « Security « Java

1. Java
2. Security
3. SHA

SHA1 Sum

    
/**
 * This file is distributed under the GPL
 * $Id: SHA1Sum.java 1810 2009-06-22 17:33:07Z scotta $
 */

//package net.bnubot.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.security.MessageDigest;

//import net.bnubot.logging.Out;

/**
 * @author scotta
 */
public class SHA1Sum {
  private final byte[] sha1sum;
  private String display = null;

  public SHA1Sum(String hexStr) throws Exception {
    if(!hexStr.matches("[0-9a-fA-F]{40}"))
      throw new Exception("Invalid format: " + hexStr);
    display = hexStr.toLowerCase();
    sha1sum = new byte[20];
    for(int i = 0; i < 20; i++) {
      int pos = i << 1;
      sha1sum[i] = (byte) Integer.parseInt(hexStr.substring(pos, pos+2), 16);
    }
  }

  public SHA1Sum(byte[] bytes) throws Exception {
    MessageDigest digest = MessageDigest.getInstance("SHA1");
    digest.update(bytes, 0, bytes.length);
    sha1sum = digest.digest();
  }

  public SHA1Sum(File f) throws Exception {
    MessageDigest digest = MessageDigest.getInstance("SHA1");
    InputStream is = new FileInputStream(f);
    byte[] buffer = new byte[8192];
    do {
      int read = is.read(buffer);
      if(read <= 0)
        break;
      digest.update(buffer, 0, read);
    } while(true);
    sha1sum = digest.digest();

  
  }

  private static String hexChr(int b) {
    return Integer.toHexString(b & 0xF);
  }

  private static String toHex(int b) {
    return hexChr((b & 0xF0) >> 4) + hexChr(b & 0x0F);
  }

  @Override
  public String toString() {
    if(display == null) {
      display = "";
      for(byte b : sha1sum)
        display += toHex(b);
    }
    return display;
  }

  public byte[] getSum() {
    return sha1sum;
  }

  @Override
  public boolean equals(Object obj) {
    if(!(obj instanceof SHA1Sum))
      return false;

    byte[] obj_sha1sum = ((SHA1Sum)obj).sha1sum;
    if(sha1sum.length != obj_sha1sum.length)
      return false;

    for(int i = 0; i < sha1sum.length; i++)
      if(sha1sum[i] != obj_sha1sum[i])
        return false;

    return true;
  }
}

   
    
    
    
  

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