/*
 * Created on Apr 12, 2004
 * Created by Olivier Chalouhi
 * Modified Apr 13, 2004 by Alon Rohter
 * Copyright (C) 2004, 2005, 2006 Aelitis, All Rights Reserved.
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * AELITIS, SAS au capital de 46,603.30 euros
 * 8 Allee Lenotre, La Grille Royale, 78600 Le Mesnil le Roi, France.
 * 
 */

package org.gudy.azureus2.core3.util;

import java.nio.ByteBuffer;


/**
 * SHA-1 message digest class.
 */
public final class SHA1 {

	private int h0,h1,h2,h3,h4;
	private ByteBuffer finalBuffer;

	private ByteBuffer saveBuffer;
	private int s0,s1,s2,s3,s4;

	private long length;
	private long saveLength;


	/**
	 * Create a new SHA-1 message digest hasher.
	 */
	public SHA1() {
		finalBuffer = ByteBuffer.allocate(64);
		finalBuffer.position(0);
		finalBuffer.limit(64);

		saveBuffer = ByteBuffer.allocate(64);
		saveBuffer.position(0);
		saveBuffer.limit(64);

		reset();
	}

	final private void transform(final byte[] ar, int offset) {
		int w0, w1, w2, w3, w4, w5, w6, w7, w8, w9, w10, w11, w12, w13, w14, w15;

		int a,b,c,d,e;

		/*
		 * we're using direct array access instead of buffer.getInt() since it is significantly faster
		 * combined with the chunk-fetching on direct byte buffers this is 30(direct) to 100%(heap) faster
		 * than the previous implementation
		 */
		w0 = (ar[offset++]&0xff) << 24 | (ar[offset++]&0xff) << 16 | (ar[offset++]&0xff) << 8 | (ar[offset++]&0xff);
		w1 = (ar[offset++]&0xff) << 24 | (ar[offset++]&0xff) << 16 | (ar[offset++]&0xff) << 8 | (ar[offset++]&0xff);
		w2 = (ar[offset++]&0xff) << 24 | (ar[offset++]&0xff) << 16 | (ar[offset++]&0xff) << 8 | (ar[offset++]&0xff);
		w3 = (ar[offset++]&0xff) << 24 | (ar[offset++]&0xff) << 16 | (ar[offset++]&0xff) << 8 | (ar[offset++]&0xff);
		w4 = (ar[offset++]&0xff) << 24 | (ar[offset++]&0xff) << 16 | (ar[offset++]&0xff) << 8 | (ar[offset++]&0xff);
		w5 = (ar[offset++]&0xff) << 24 | (ar[offset++]&0xff) << 16 | (ar[offset++]&0xff) << 8 | (ar[offset++]&0xff);
		w6 = (ar[offset++]&0xff) << 24 | (ar[offset++]&0xff) << 16 | (ar[offset++]&0xff) << 8 | (ar[offset++]&0xff);
		w7 = (ar[offset++]&0xff) << 24 | (ar[offset++]&0xff) << 16 | (ar[offset++]&0xff) << 8 | (ar[offset++]&0xff);
		w8 = (ar[offset++]&0xff) << 24 | (ar[offset++]&0xff) << 16 | (ar[offset++]&0xff) << 8 | (ar[offset++]&0xff);
		w9 = (ar[offset++]&0xff) << 24 | (ar[offset++]&0xff) << 16 | (ar[offset++]&0xff) << 8 | (ar[offset++]&0xff);
		w10 = (ar[offset++]&0xff) << 24 | (ar[offset++]&0xff) << 16 | (ar[offset++]&0xff) << 8 | (ar[offset++]&0xff);
		w11 = (ar[offset++]&0xff) << 24 | (ar[offset++]&0xff) << 16 | (ar[offset++]&0xff) << 8 | (ar[offset++]&0xff);
		w12 = (ar[offset++]&0xff) << 24 | (ar[offset++]&0xff) << 16 | (ar[offset++]&0xff) << 8 | (ar[offset++]&0xff);
		w13 = (ar[offset++]&0xff) << 24 | (ar[offset++]&0xff) << 16 | (ar[offset++]&0xff) << 8 | (ar[offset++]&0xff);
		w14 = (ar[offset++]&0xff) << 24 | (ar[offset++]&0xff) << 16 | (ar[offset++]&0xff) << 8 | (ar[offset++]&0xff);
		w15 = (ar[offset++]&0xff) << 24 | (ar[offset++]&0xff) << 16 | (ar[offset++]&0xff) << 8 | (ar[offset]&0xff);

		a = h0 ; b = h1 ; c = h2 ; d = h3 ; e = h4;
		e += ((a << 5) | ( a >>> 27)) + w0 + ((b & c) | ((~b ) & d)) + 0x5A827999 ;
		b = (b << 30) | (b >>> 2) ;
		d += ((e << 5) | ( e >>> 27)) + w1 + ((a & b) | ((~a ) & c)) + 0x5A827999 ;
		a = (a << 30) | (a >>> 2) ;
		c += ((d << 5) | ( d >>> 27)) + w2 + ((e & a) | ((~e ) & b)) + 0x5A827999 ;
		e = (e << 30) | (e >>> 2) ;
		b += ((c << 5) | ( c >>> 27)) + w3 + ((d & e) | ((~d ) & a)) + 0x5A827999 ;
		d = (d << 30) | (d >>> 2) ;
		a += ((b << 5) | ( b >>> 27)) + w4 + ((c & d) | ((~c ) & e)) + 0x5A827999 ;
		c = (c << 30) | (c >>> 2) ;
		e += ((a << 5) | ( a >>> 27)) + w5 + ((b & c) | ((~b ) & d)) + 0x5A827999 ;
		b = (b << 30) | (b >>> 2) ;
		d += ((e << 5) | ( e >>> 27)) + w6 + ((a & b) | ((~a ) & c)) + 0x5A827999 ;
		a = (a << 30) | (a >>> 2) ;
		c += ((d << 5) | ( d >>> 27)) + w7 + ((e & a) | ((~e ) & b)) + 0x5A827999 ;
		e = (e << 30) | (e >>> 2) ;
		b += ((c << 5) | ( c >>> 27)) + w8 + ((d & e) | ((~d ) & a)) + 0x5A827999 ;
		d = (d << 30) | (d >>> 2) ;
		a += ((b << 5) | ( b >>> 27)) + w9 + ((c & d) | ((~c ) & e)) + 0x5A827999 ;
		c = (c << 30) | (c >>> 2) ;
		e += ((a << 5) | ( a >>> 27)) + w10 + ((b & c) | ((~b ) & d)) + 0x5A827999 ;
		b = (b << 30) | (b >>> 2) ;
		d += ((e << 5) | ( e >>> 27)) + w11 + ((a & b) | ((~a ) & c)) + 0x5A827999 ;
		a = (a << 30) | (a >>> 2) ;
		c += ((d << 5) | ( d >>> 27)) + w12 + ((e & a) | ((~e ) & b)) + 0x5A827999 ;
		e = (e << 30) | (e >>> 2) ;
		b += ((c << 5) | ( c >>> 27)) + w13 + ((d & e) | ((~d ) & a)) + 0x5A827999 ;
		d = (d << 30) | (d >>> 2) ;
		a += ((b << 5) | ( b >>> 27)) + w14 + ((c & d) | ((~c ) & e)) + 0x5A827999 ;
		c = (c << 30) | (c >>> 2) ;
		e += ((a << 5) | ( a >>> 27)) + w15 + ((b & c) | ((~b ) & d)) + 0x5A827999 ;
		b = (b << 30) | (b >>> 2) ;
		w0 = w13 ^ w8 ^ w2 ^ w0; w0 = (w0 << 1) | (w0 >>> 31) ;
		d += ((e << 5) | ( e >>> 27)) + w0 + ((a & b) | ((~a ) & c)) + 0x5A827999 ;
		a = (a << 30) | (a >>> 2) ;
		w1 = w14 ^ w9 ^ w3 ^ w1; w1 = (w1 << 1) | (w1 >>> 31) ;
		c += ((d << 5) | ( d >>> 27)) + w1 + ((e & a) | ((~e ) & b)) + 0x5A827999 ;
		e = (e << 30) | (e >>> 2) ;
		w2 = w15 ^ w10 ^ w4 ^ w2; w2 = (w2 << 1) | (w2 >>> 31) ;
		b += ((c << 5) | ( c >>> 27)) + w2 + ((d & e) | ((~d ) & a)) + 0x5A827999 ;
		d = (d << 30) | (d >>> 2) ;
		w3 = w0 ^ w11 ^ w5 ^ w3; w3 = (w3 << 1) | (w3 >>> 31) ;
		a += ((b << 5) | ( b >>> 27)) + w3 + ((c & d) | ((~c ) & e)) + 0x5A827999 ;
		c = (c << 30) | (c >>> 2) ;
		w4 = w1 ^ w12 ^ w6 ^ w4; w4 = (w4 << 1) | (w4 >>> 31) ;
		e += ((a << 5) | ( a >>> 27)) + w4 + (b ^ c ^ d) + 0x6ED9EBA1 ;
		b = (b << 30) | (b >>> 2) ;
		w5 = w2 ^ w13 ^ w7 ^ w5; w5 = (w5 << 1) | (w5 >>> 31) ;
		d += ((e << 5) | ( e >>> 27)) + w5 + (a ^ b ^ c) + 0x6ED9EBA1 ;
		a = (a << 30) | (a >>> 2) ;
		w6 = w3 ^ w14 ^ w8 ^ w6; w6 = (w6 << 1) | (w6 >>> 31) ;
		c += ((d << 5) | ( d >>> 27)) + w6 + (e ^ a ^ b) + 0x6ED9EBA1 ;
		e = (e << 30) | (e >>> 2) ;
		w7 = w4 ^ w15 ^ w9 ^ w7; w7 = (w7 << 1) | (w7 >>> 31) ;
		b += ((c << 5) | ( c >>> 27)) + w7 + (d ^ e ^ a) + 0x6ED9EBA1 ;
		d = (d << 30) | (d >>> 2) ;
		w8 = w5 ^ w0 ^ w10 ^ w8; w8 = (w8 << 1) | (w8 >>> 31) ;
		a += ((b << 5) | ( b >>> 27)) + w8 + (c ^ d ^ e) + 0x6ED9EBA1 ;
		c = (c << 30) | (c >>> 2) ;
		w9 = w6 ^ w1 ^ w11 ^ w9; w9 = (w9 << 1) | (w9 >>> 31) ;
		e += ((a << 5) | ( a >>> 27)) + w9 + (b ^ c ^ d) + 0x6ED9EBA1 ;
		b = (b << 30) | (b >>> 2) ;
		w10 = w7 ^ w2 ^ w12 ^ w10; w10 = (w10 << 1) | (w10 >>> 31) ;
		d += ((e << 5) | ( e >>> 27)) + w10 + (a ^ b ^ c) + 0x6ED9EBA1 ;
		a = (a << 30) | (a >>> 2) ;
		w11 = w8 ^ w3 ^ w13 ^ w11; w11 = (w11 << 1) | (w11 >>> 31) ;
		c += ((d << 5) | ( d >>> 27)) + w11 + (e ^ a ^ b) + 0x6ED9EBA1 ;
		e = (e << 30) | (e >>> 2) ;
		w12 = w9 ^ w4 ^ w14 ^ w12; w12 = (w12 << 1) | (w12 >>> 31) ;
		b += ((c << 5) | ( c >>> 27)) + w12 + (d ^ e ^ a) + 0x6ED9EBA1 ;
		d = (d << 30) | (d >>> 2) ;
		w13 = w10 ^ w5 ^ w15 ^ w13; w13 = (w13 << 1) | (w13 >>> 31) ;
		a += ((b << 5) | ( b >>> 27)) + w13 + (c ^ d ^ e) + 0x6ED9EBA1 ;
		c = (c << 30) | (c >>> 2) ;
		w14 = w11 ^ w6 ^ w0 ^ w14; w14 = (w14 << 1) | (w14 >>> 31) ;
		e += ((a << 5) | ( a >>> 27)) + w14 + (b ^ c ^ d) + 0x6ED9EBA1 ;
		b = (b << 30) | (b >>> 2) ;
		w15 = w12 ^ w7 ^ w1 ^ w15; w15 = (w15 << 1) | (w15 >>> 31) ;
		d += ((e << 5) | ( e >>> 27)) + w15 + (a ^ b ^ c) + 0x6ED9EBA1 ;
		a = (a << 30) | (a >>> 2) ;
		w0 = w13 ^ w8 ^ w2 ^ w0; w0 = (w0 << 1) | (w0 >>> 31) ;
		c += ((d << 5) | ( d >>> 27)) + w0 + (e ^ a ^ b) + 0x6ED9EBA1 ;
		e = (e << 30) | (e >>> 2) ;
		w1 = w14 ^ w9 ^ w3 ^ w1; w1 = (w1 << 1) | (w1 >>> 31) ;
		b += ((c << 5) | ( c >>> 27)) + w1 + (d ^ e ^ a) + 0x6ED9EBA1 ;
		d = (d << 30) | (d >>> 2) ;
		w2 = w15 ^ w10 ^ w4 ^ w2; w2 = (w2 << 1) | (w2 >>> 31) ;
		a += ((b << 5) | ( b >>> 27)) + w2 + (c ^ d ^ e) + 0x6ED9EBA1 ;
		c = (c << 30) | (c >>> 2) ;
		w3 = w0 ^ w11 ^ w5 ^ w3; w3 = (w3 << 1) | (w3 >>> 31) ;
		e += ((a << 5) | ( a >>> 27)) + w3 + (b ^ c ^ d) + 0x6ED9EBA1 ;
		b = (b << 30) | (b >>> 2) ;
		w4 = w1 ^ w12 ^ w6 ^ w4; w4 = (w4 << 1) | (w4 >>> 31) ;
		d += ((e << 5) | ( e >>> 27)) + w4 + (a ^ b ^ c) + 0x6ED9EBA1 ;
		a = (a << 30) | (a >>> 2) ;
		w5 = w2 ^ w13 ^ w7 ^ w5; w5 = (w5 << 1) | (w5 >>> 31) ;
		c += ((d << 5) | ( d >>> 27)) + w5 + (e ^ a ^ b) + 0x6ED9EBA1 ;
		e = (e << 30) | (e >>> 2) ;
		w6 = w3 ^ w14 ^ w8 ^ w6; w6 = (w6 << 1) | (w6 >>> 31) ;
		b += ((c << 5) | ( c >>> 27)) + w6 + (d ^ e ^ a) + 0x6ED9EBA1 ;
		d = (d << 30) | (d >>> 2) ;
		w7 = w4 ^ w15 ^ w9 ^ w7; w7 = (w7 << 1) | (w7 >>> 31) ;
		a += ((b << 5) | ( b >>> 27)) + w7 + (c ^ d ^ e) + 0x6ED9EBA1 ;
		c = (c << 30) | (c >>> 2) ;
		w8 = w5 ^ w0 ^ w10 ^ w8; w8 = (w8 << 1) | (w8 >>> 31) ;
		e += ((a << 5) | ( a >>> 27)) + w8 + ((b & c) | (b & d) | (c & d)) + 0x8F1BBCDC ;
		b = (b << 30) | (b >>> 2) ;
		w9 = w6 ^ w1 ^ w11 ^ w9; w9 = (w9 << 1) | (w9 >>> 31) ;
		d += ((e << 5) | ( e >>> 27)) + w9 + ((a & b) | (a & c) | (b & c)) + 0x8F1BBCDC ;
		a = (a << 30) | (a >>> 2) ;
		w10 = w7 ^ w2 ^ w12 ^ w10; w10 = (w10 << 1) | (w10 >>> 31) ;
		c += ((d << 5) | ( d >>> 27)) + w10 + ((e & a) | (e & b) | (a & b)) + 0x8F1BBCDC ;
		e = (e << 30) | (e >>> 2) ;
		w11 = w8 ^ w3 ^ w13 ^ w11; w11 = (w11 << 1) | (w11 >>> 31) ;
		b += ((c << 5) | ( c >>> 27)) + w11 + ((d & e) | (d & a) | (e & a)) + 0x8F1BBCDC ;
		d = (d << 30) | (d >>> 2) ;
		w12 = w9 ^ w4 ^ w14 ^ w12; w12 = (w12 << 1) | (w12 >>> 31) ;
		a += ((b << 5) | ( b >>> 27)) + w12 + ((c & d) | (c & e) | (d & e)) + 0x8F1BBCDC ;
		c = (c << 30) | (c >>> 2) ;
		w13 = w10 ^ w5 ^ w15 ^ w13; w13 = (w13 << 1) | (w13 >>> 31) ;
		e += ((a << 5) | ( a >>> 27)) + w13 + ((b & c) | (b & d) | (c & d)) + 0x8F1BBCDC ;
		b = (b << 30) | (b >>> 2) ;
		w14 = w11 ^ w6 ^ w0 ^ w14; w14 = (w14 << 1) | (w14 >>> 31) ;
		d += ((e << 5) | ( e >>> 27)) + w14 + ((a & b) | (a & c) | (b & c)) + 0x8F1BBCDC ;
		a = (a << 30) | (a >>> 2) ;
		w15 = w12 ^ w7 ^ w1 ^ w15; w15 = (w15 << 1) | (w15 >>> 31) ;
		c += ((d << 5) | ( d >>> 27)) + w15 + ((e & a) | (e & b) | (a & b)) + 0x8F1BBCDC ;
		e = (e << 30) | (e >>> 2) ;
		w0 = w13 ^ w8 ^ w2 ^ w0; w0 = (w0 << 1) | (w0 >>> 31) ;
		b += ((c << 5) | ( c >>> 27)) + w0 + ((d & e) | (d & a) | (e & a)) + 0x8F1BBCDC ;
		d = (d << 30) | (d >>> 2) ;
		w1 = w14 ^ w9 ^ w3 ^ w1; w1 = (w1 << 1) | (w1 >>> 31) ;
		a += ((b << 5) | ( b >>> 27)) + w1 + ((c & d) | (c & e) | (d & e)) + 0x8F1BBCDC ;
		c = (c << 30) | (c >>> 2) ;
		w2 = w15 ^ w10 ^ w4 ^ w2; w2 = (w2 << 1) | (w2 >>> 31) ;
		e += ((a << 5) | ( a >>> 27)) + w2 + ((b & c) | (b & d) | (c & d)) + 0x8F1BBCDC ;
		b = (b << 30) | (b >>> 2) ;
		w3 = w0 ^ w11 ^ w5 ^ w3; w3 = (w3 << 1) | (w3 >>> 31) ;
		d += ((e << 5) | ( e >>> 27)) + w3 + ((a & b) | (a & c) | (b & c)) + 0x8F1BBCDC ;
		a = (a << 30) | (a >>> 2) ;
		w4 = w1 ^ w12 ^ w6 ^ w4; w4 = (w4 << 1) | (w4 >>> 31) ;
		c += ((d << 5) | ( d >>> 27)) + w4 + ((e & a) | (e & b) | (a & b)) + 0x8F1BBCDC ;
		e = (e << 30) | (e >>> 2) ;
		w5 = w2 ^ w13 ^ w7 ^ w5; w5 = (w5 << 1) | (w5 >>> 31) ;
		b += ((c << 5) | ( c >>> 27)) + w5 + ((d & e) | (d & a) | (e & a)) + 0x8F1BBCDC ;
		d = (d << 30) | (d >>> 2) ;
		w6 = w3 ^ w14 ^ w8 ^ w6; w6 = (w6 << 1) | (w6 >>> 31) ;
		a += ((b << 5) | ( b >>> 27)) + w6 + ((c & d) | (c & e) | (d & e)) + 0x8F1BBCDC ;
		c = (c << 30) | (c >>> 2) ;
		w7 = w4 ^ w15 ^ w9 ^ w7; w7 = (w7 << 1) | (w7 >>> 31) ;
		e += ((a << 5) | ( a >>> 27)) + w7 + ((b & c) | (b & d) | (c & d)) + 0x8F1BBCDC ;
		b = (b << 30) | (b >>> 2) ;
		w8 = w5 ^ w0 ^ w10 ^ w8; w8 = (w8 << 1) | (w8 >>> 31) ;
		d += ((e << 5) | ( e >>> 27)) + w8 + ((a & b) | (a & c) | (b & c)) + 0x8F1BBCDC ;
		a = (a << 30) | (a >>> 2) ;
		w9 = w6 ^ w1 ^ w11 ^ w9; w9 = (w9 << 1) | (w9 >>> 31) ;
		c += ((d << 5) | ( d >>> 27)) + w9 + ((e & a) | (e & b) | (a & b)) + 0x8F1BBCDC ;
		e = (e << 30) | (e >>> 2) ;
		w10 = w7 ^ w2 ^ w12 ^ w10; w10 = (w10 << 1) | (w10 >>> 31) ;
		b += ((c << 5) | ( c >>> 27)) + w10 + ((d & e) | (d & a) | (e & a)) + 0x8F1BBCDC ;
		d = (d << 30) | (d >>> 2) ;
		w11 = w8 ^ w3 ^ w13 ^ w11; w11 = (w11 << 1) | (w11 >>> 31) ;
		a += ((b << 5) | ( b >>> 27)) + w11 + ((c & d) | (c & e) | (d & e)) + 0x8F1BBCDC ;
		c = (c << 30) | (c >>> 2) ;
		w12 = w9 ^ w4 ^ w14 ^ w12; w12 = (w12 << 1) | (w12 >>> 31) ;
		e += ((a << 5) | ( a >>> 27)) + w12 + (b ^ c ^ d) + 0xCA62C1D6 ;
		b = (b << 30) | (b >>> 2) ;
		w13 = w10 ^ w5 ^ w15 ^ w13; w13 = (w13 << 1) | (w13 >>> 31) ;
		d += ((e << 5) | ( e >>> 27)) + w13 + (a ^ b ^ c) + 0xCA62C1D6 ;
		a = (a << 30) | (a >>> 2) ;
		w14 = w11 ^ w6 ^ w0 ^ w14; w14 = (w14 << 1) | (w14 >>> 31) ;
		c += ((d << 5) | ( d >>> 27)) + w14 + (e ^ a ^ b) + 0xCA62C1D6 ;
		e = (e << 30) | (e >>> 2) ;
		w15 = w12 ^ w7 ^ w1 ^ w15; w15 = (w15 << 1) | (w15 >>> 31) ;
		b += ((c << 5) | ( c >>> 27)) + w15 + (d ^ e ^ a) + 0xCA62C1D6 ;
		d = (d << 30) | (d >>> 2) ;
		w0 = w13 ^ w8 ^ w2 ^ w0; w0 = (w0 << 1) | (w0 >>> 31) ;
		a += ((b << 5) | ( b >>> 27)) + w0 + (c ^ d ^ e) + 0xCA62C1D6 ;
		c = (c << 30) | (c >>> 2) ;
		w1 = w14 ^ w9 ^ w3 ^ w1; w1 = (w1 << 1) | (w1 >>> 31) ;
		e += ((a << 5) | ( a >>> 27)) + w1 + (b ^ c ^ d) + 0xCA62C1D6 ;
		b = (b << 30) | (b >>> 2) ;
		w2 = w15 ^ w10 ^ w4 ^ w2; w2 = (w2 << 1) | (w2 >>> 31) ;
		d += ((e << 5) | ( e >>> 27)) + w2 + (a ^ b ^ c) + 0xCA62C1D6 ;
		a = (a << 30) | (a >>> 2) ;
		w3 = w0 ^ w11 ^ w5 ^ w3; w3 = (w3 << 1) | (w3 >>> 31) ;
		c += ((d << 5) | ( d >>> 27)) + w3 + (e ^ a ^ b) + 0xCA62C1D6 ;
		e = (e << 30) | (e >>> 2) ;
		w4 = w1 ^ w12 ^ w6 ^ w4; w4 = (w4 << 1) | (w4 >>> 31) ;
		b += ((c << 5) | ( c >>> 27)) + w4 + (d ^ e ^ a) + 0xCA62C1D6 ;
		d = (d << 30) | (d >>> 2) ;
		w5 = w2 ^ w13 ^ w7 ^ w5; w5 = (w5 << 1) | (w5 >>> 31) ;
		a += ((b << 5) | ( b >>> 27)) + w5 + (c ^ d ^ e) + 0xCA62C1D6 ;
		c = (c << 30) | (c >>> 2) ;
		w6 = w3 ^ w14 ^ w8 ^ w6; w6 = (w6 << 1) | (w6 >>> 31) ;
		e += ((a << 5) | ( a >>> 27)) + w6 + (b ^ c ^ d) + 0xCA62C1D6 ;
		b = (b << 30) | (b >>> 2) ;
		w7 = w4 ^ w15 ^ w9 ^ w7; w7 = (w7 << 1) | (w7 >>> 31) ;
		d += ((e << 5) | ( e >>> 27)) + w7 + (a ^ b ^ c) + 0xCA62C1D6 ;
		a = (a << 30) | (a >>> 2) ;
		w8 = w5 ^ w0 ^ w10 ^ w8; w8 = (w8 << 1) | (w8 >>> 31) ;
		c += ((d << 5) | ( d >>> 27)) + w8 + (e ^ a ^ b) + 0xCA62C1D6 ;
		e = (e << 30) | (e >>> 2) ;
		w9 = w6 ^ w1 ^ w11 ^ w9; w9 = (w9 << 1) | (w9 >>> 31) ;
		b += ((c << 5) | ( c >>> 27)) + w9 + (d ^ e ^ a) + 0xCA62C1D6 ;
		d = (d << 30) | (d >>> 2) ;
		w10 = w7 ^ w2 ^ w12 ^ w10; w10 = (w10 << 1) | (w10 >>> 31) ;
		a += ((b << 5) | ( b >>> 27)) + w10 + (c ^ d ^ e) + 0xCA62C1D6 ;
		c = (c << 30) | (c >>> 2) ;
		w11 = w8 ^ w3 ^ w13 ^ w11; w11 = (w11 << 1) | (w11 >>> 31) ;
		e += ((a << 5) | ( a >>> 27)) + w11 + (b ^ c ^ d) + 0xCA62C1D6 ;
		b = (b << 30) | (b >>> 2) ;
		w12 = w9 ^ w4 ^ w14 ^ w12; w12 = (w12 << 1) | (w12 >>> 31) ;
		d += ((e << 5) | ( e >>> 27)) + w12 + (a ^ b ^ c) + 0xCA62C1D6 ;
		a = (a << 30) | (a >>> 2) ;
		w13 = w10 ^ w5 ^ w15 ^ w13; w13 = (w13 << 1) | (w13 >>> 31) ;
		c += ((d << 5) | ( d >>> 27)) + w13 + (e ^ a ^ b) + 0xCA62C1D6 ;
		e = (e << 30) | (e >>> 2) ;
		w14 = w11 ^ w6 ^ w0 ^ w14; w14 = (w14 << 1) | (w14 >>> 31) ;
		b += ((c << 5) | ( c >>> 27)) + w14 + (d ^ e ^ a) + 0xCA62C1D6 ;
		d = (d << 30) | (d >>> 2) ;
		w15 = w12 ^ w7 ^ w1 ^ w15; w15 = (w15 << 1) | (w15 >>> 31) ;
		a += ((b << 5) | ( b >>> 27)) + w15 + (c ^ d ^ e) + 0xCA62C1D6 ;
		c = (c << 30) | (c >>> 2) ;

		h0 += a;
		h1 += b;
		h2 += c;
		h3 += d;
		h4 += e;
	}


	private void completeFinalBuffer(ByteBuffer buffer) {
		if(finalBuffer.position() == 0) 
			return;

		while(buffer.remaining() > 0 && finalBuffer.remaining() > 0) {
			finalBuffer.put(buffer.get());
		}

		if(finalBuffer.remaining() == 0) {
			transform(finalBuffer.array(),0);
			finalBuffer.rewind();
		}
	}



	/**
	 * Resets the SHA-1 to initial state for a new message digest calculation.
	 * Must be called before starting a new hash calculation.
	 */
	 public void reset() {
		 h0 = 0x67452301;
		 h1 = 0xEFCDAB89;
		 h2 = 0x98BADCFE;
		 h3 = 0x10325476;    
		 h4 = 0xC3D2E1F0;    

		 length = 0;

		 finalBuffer.clear();
	 }


	// must be a multiple of 64
	private static final int cacheSize = 4*1024;
	// cache block to reduce expensive native access for direct byte buffers
	private byte[] cacheBlock; 

	/**
	 * Starts or continues a SHA-1 message digest calculation.
	 * Only the remaining bytes of the given ByteBuffer are used.
	 * @param buffer input data
	 */
	public void update(ByteBuffer buffer) {
		length += buffer.remaining();
		//Save current position to leave given buffer unchanged
		int position = buffer.position();

		//Complete the final buffer if needed
		completeFinalBuffer(buffer);

		if(!buffer.hasArray() || buffer.isDirect())
		{
			if(cacheBlock == null) // only allocate if we process direct byte buffers
				cacheBlock = new byte[cacheSize];
			while(buffer.remaining() >= 64)
			{
				int toProcess = Math.min(buffer.remaining()-buffer.remaining()%64,cacheSize);
				buffer.get(cacheBlock, 0, toProcess);
				for(int i = 0;i < toProcess; i+=64)
					transform(cacheBlock,i);
			}
		} else // use direct array access for heap buffers
		{
			final int endPos = buffer.position()+buffer.remaining()-buffer.remaining()%64;
			final int internalEndPos = endPos+buffer.arrayOffset(); 
			for(int i = buffer.arrayOffset()+buffer.position();i < internalEndPos;i+=64)
				transform(buffer.array(),i);
			buffer.position(endPos);
		}


		if(buffer.remaining() != 0) {
			finalBuffer.put(buffer);
		}

		buffer.position(position);
	}


	/**
	 * Finishes the SHA-1 message digest calculation.
	 * @return 20-byte hash result
	 */
	public byte[] digest() {
		byte[] result = new byte[20];

		finalBuffer.put((byte)0x80);
		if(finalBuffer.remaining() < 8) {
			while(finalBuffer.remaining() > 0) {
				finalBuffer.put((byte)0);
			}
			finalBuffer.position(0);
			transform(finalBuffer.array(),0);
			finalBuffer.position(0);
		}

		while(finalBuffer.remaining() > 8) {
			finalBuffer.put((byte)0);
		}

		finalBuffer.putLong(length << 3);
		finalBuffer.position(0);
		transform(finalBuffer.array(),0);

		finalBuffer.position(0);
		finalBuffer.putInt(h0);
		finalBuffer.putInt(h1);
		finalBuffer.putInt(h2);
		finalBuffer.putInt(h3);
		finalBuffer.putInt(h4);    
		finalBuffer.rewind();

		finalBuffer.get(result, 0, 20);

		return result;
	}


	/**
	 * Finishes the SHA-1 message digest calculation, by first performing a final update
	 * from the given input buffer, then completing the calculation as with digest().
	 * @param buffer input data
	 * @return 20-byte hash result
	 */
	public byte[] digest(ByteBuffer buffer) {
		update( buffer );
		return digest();
	}



	/**
	 * Save the current digest state.
	 * This allows the resuming of a SHA-1 calculation, even after a digest calculation
	 * is finished with digest().
	 */
	public void saveState() {
		s0=h0;
		s1=h1;
		s2=h2;
		s3=h3;
		s4=h4;

		saveLength = length;

		int position = finalBuffer.position();

		finalBuffer.rewind();
		finalBuffer.limit(position);

		saveBuffer.clear();
		saveBuffer.put(finalBuffer);
		saveBuffer.flip();

		finalBuffer.limit(64);
		finalBuffer.position( position );
	}


	/**
	 * Restore the digest to its previously-saved state.
	 */
	public void restoreState() {
		h0=s0;
		h1=s1;
		h2=s2;
		h3=s3;
		h4=s4;

		length = saveLength;

		finalBuffer.clear();
		finalBuffer.put(saveBuffer);
	}


}
