md5.java

java操作excel的类

	 * @since ostermillerutils 1.00.00
	 */
	public void update (byte buffer[], int length) {
		update(buffer, 0, length);
	}

	/** 
	 * Update this hash with the given data.
	 *
	 * @param buffer Array of bytes to be hashed.
	 *
	 * @since ostermillerutils 1.00.00
	 */
	public void update (byte buffer[]) {
		update(buffer, 0, buffer.length);
	}

	/**
	 * Updates this hash with a single byte.
	 *
	 * @param b byte to be hashed.
	 *
	 * @since ostermillerutils 1.00.00
	 */
	public void update (byte b) {
		byte buffer[] = new byte[1];
		buffer[0] = b;
		update(buffer, 1);
	}

	/**
	 * Update this hash with a long.
	 * This hash will be updated in a little endian order with the
	 * the least significant byte going first.
	 *
	 * @param l long to be hashed.
	 *
	 * @since ostermillerutils 1.00.00
	 */
	private void update (MD5State state, long l) {
		update(
			state, 
			new byte[] {
				(byte)((l >>> 0) & 0xff),
				(byte)((l >>> 8) & 0xff),
				(byte)((l >>> 16) & 0xff),
				(byte)((l >>> 24) & 0xff),
				(byte)((l >>> 32) & 0xff),
				(byte)((l >>> 40) & 0xff),
				(byte)((l >>> 48) & 0xff),
				(byte)((l >>> 56) & 0xff),
			},
			0,
			8
		);
	}

	/**
	 * Update this hash with a String.
	 * The string is converted to bytes using the current
	 * platform's default character encoding.
	 * 
	 * @param s String to be hashed.
	 *
	 * @since ostermillerutils 1.00.00
	 */
	public void update (String s) {
		update(s.getBytes());
	}   

	/**
	 * Update this hash with a String.
	 * 
	 * @param s String to be hashed.
	 * @param enc The name of a supported character encoding.
	 * @throws UnsupportedEncodingException If the named encoding is not supported.
	 *
	 * @since ostermillerutils 1.00.00
	 */
	public void update (String s, String enc) throws UnsupportedEncodingException {
		update(s.getBytes(enc));
	}

	/**
	 * The current state from which the hash sum
	 * can be computed or updated.
	 *
	 * @since ostermillerutils 1.00.00
	 */
	private MD5State workingState = new MD5State();

	/**
	 * Cached copy of the final MD5 hash sum.  This is created when
	 * the hash is requested and it is invalidated when the hash
	 * is updated.
	 *
	 * @since ostermillerutils 1.00.00
	 */
	private MD5State finalState = new MD5State();

	/**
	 * Temporary buffer cached here for performance reasons.
	 *
	 * @since ostermillerutils 1.00.00
	 */   
	private int[] decodeBuffer = new int[16];

	/** 
	 * 64 bytes of padding that can be added if the length
	 * is not divisible by 64.
	 *
	 * @since ostermillerutils 1.00.00
	 */
	private static final byte padding[] = {
		(byte) 0x80, 0, 0, 0, 0, 0, 0, 0, 
				0, 0, 0, 0, 0, 0, 0, 0, 
				0, 0, 0, 0, 0, 0, 0, 0, 
				0, 0, 0, 0, 0, 0, 0, 0, 
				0, 0, 0, 0, 0, 0, 0, 0, 
				0, 0, 0, 0, 0, 0, 0, 0,
				0, 0, 0, 0, 0, 0, 0, 0, 
				0, 0, 0, 0, 0, 0, 0, 0,
	};

	/**
	 * Contains internal state of the MD5 class.
	 * Passes MD5 test suite as defined in RFC1321.
	 *
	 * @since ostermillerutils 1.00.00
	 */
	private class MD5State {

		/**
		 * True if this state is valid.
		 *
		 * @since ostermillerutils 1.00.00
		 */
		public boolean valid = true;

		/**
		 * Reset to initial state.
		 *
		 * @since ostermillerutils 1.00.00
		 */
		public void reset(){
			state[0] = 0x67452301;
			state[1] = 0xefcdab89;
			state[2] = 0x98badcfe;
			state[3] = 0x10325476;

			bitCount = 0;
		}

		/**
		 * 128-byte state 
		 *
		 * @since ostermillerutils 1.00.00
		 */
		public int state[] = new int[4];

		/**
		 * 64-bit count of the number of bits that have been hashed.
		 *
		 * @since ostermillerutils 1.00.00
		 */        
		public long bitCount;

		/**
		 * 64-byte buffer (512 bits) for storing to-be-hashed characters
		 *
		 * @since ostermillerutils 1.00.00
		 */
		public byte buffer[] = new byte[64];

		public MD5State() { 
			reset();
		}

		/** 
		 * Set this state to be exactly the same as some other.
		 *
		 * @param from state to copy from.
		 *
		 * @since ostermillerutils 1.00.00
		 */
		public void copy(MD5State from) {
			System.arraycopy(from.buffer, 0, this.buffer, 0, this.buffer.length);
			System.arraycopy(from.state, 0, this.state, 0, this.state.length);
			this.valid = from.valid;
			this.bitCount = from.bitCount;
		}

		public String toString(){
			return state[0] + " " + state[1] + " " + state[2] + " " + state[3];
		}
	}


	/**
	 * Turns array of bytes into string representing each byte as
	 * a two digit unsigned hex number.
	 * 
	 * @param hash Array of bytes to convert to hex-string
	 * @return  Generated hex string
	 *
	 * @since ostermillerutils 1.00.00
	 */
	private static String toHex(byte hash[]){
		StringBuffer buf = new StringBuffer(hash.length * 2);
		for (int i=0; i<hash.length; i++){
			int intVal = hash[i] & 0xff;
			if (intVal < 0x10){
				// append a zero before a one digit hex 
				// number to make it two digits.
				buf.append("0");
			}
			buf.append(Integer.toHexString(intVal));
		}
		return buf.toString();
	}

	private static int FF (int a, int b, int c, int d, int x, int s, int ac) {
		a += ((b & c) | (~b & d)); 
		a += x;
		a += ac;
		//return rotateLeft(a, s) + b;
		a = (a << s) | (a >>> (32 - s));
		return a + b;
	}

	private static int GG (int a, int b, int c, int d, int x, int s, int ac) {
		a += ((b & d) | (c & ~d)); 
		a += x;
		a += ac;
		//return rotateLeft(a, s) + b;
		a = (a << s) | (a >>> (32 - s));
		return a + b;
	}

	private static int HH (int a, int b, int c, int d, int x, int s, int ac) { 
		a += (b ^ c ^ d); 
		a += x;
		a += ac;
		//return rotateLeft(a, s) + b;
		a = (a << s) | (a >>> (32 - s));
		return a + b;
	}

	private static int II (int a, int b, int c, int d, int x, int s, int ac) {
		a += (c ^ (b | ~d)); 
		a += x;
		a += ac;        
		//return rotateLeft(a, s) + b;
		a = (a << s) | (a >>> (32 - s));
		return a + b;
	}

	private static byte[] encode(long l){
		byte[] out = new byte[8];
		out[0] = (byte) (l & 0xff);
		out[1] = (byte) ((l >>> 8) & 0xff);
		out[2] = (byte) ((l >>> 16) & 0xff);
		out[3] = (byte) ((l >>> 24) & 0xff);
		out[4] = (byte) ((l >>> 32) & 0xff);
		out[5] = (byte) ((l >>> 40) & 0xff);
		out[6] = (byte) ((l >>> 48) & 0xff);
		out[7] = (byte) ((l >>> 56) & 0xff);
		return out;
	}

	private static byte[] encode(int input[], int len){
		byte[] out = new byte[len];
		int i, j;
		for (i = j = 0; j  < len; i++, j += 4) {
			out[j] = (byte) (input[i] & 0xff);
			out[j + 1] = (byte) ((input[i] >>> 8) & 0xff);
			out[j + 2] = (byte) ((input[i] >>> 16) & 0xff);
			out[j + 3] = (byte) ((input[i] >>> 24) & 0xff);
		}
		return out;
	}

	private int[] decode(byte buffer[], int len, int offset){
		int i, j;
		for (i = j = 0; j < len; i++, j += 4) {
			decodeBuffer[i] = (
				(int) (buffer[j + offset] & 0xff)) | 
				(((int) (buffer[j + 1 + offset] & 0xff)) << 8) |
				(((int) (buffer[j + 2 + offset] & 0xff)) << 16) | 
				(((int) (buffer[j + 3 + offset] & 0xff)) << 24
			);
		}
		return decodeBuffer;
	}

	private static void transform(MD5State state, int[] x){         
		int a = state.state[0];
		int b = state.state[1];
		int c = state.state[2];
		int d = state.state[3];

		/* Round 1 */
		a = FF (a, b, c, d, x[ 0],   7, 0xd76aa478); /* 1 */
		d = FF (d, a, b, c, x[ 1],  12, 0xe8c7b756); /* 2 */
		c = FF (c, d, a, b, x[ 2],  17, 0x242070db); /* 3 */
		b = FF (b, c, d, a, x[ 3],  22, 0xc1bdceee); /* 4 */
		a = FF (a, b, c, d, x[ 4],   7, 0xf57c0faf); /* 5 */
		d = FF (d, a, b, c, x[ 5],  12, 0x4787c62a); /* 6 */
		c = FF (c, d, a, b, x[ 6],  17, 0xa8304613); /* 7 */
		b = FF (b, c, d, a, x[ 7],  22, 0xfd469501); /* 8 */
		a = FF (a, b, c, d, x[ 8],   7, 0x698098d8); /* 9 */
		d = FF (d, a, b, c, x[ 9],  12, 0x8b44f7af); /* 10 */
		c = FF (c, d, a, b, x[10],  17, 0xffff5bb1); /* 11 */
		b = FF (b, c, d, a, x[11],  22, 0x895cd7be); /* 12 */
		a = FF (a, b, c, d, x[12],   7, 0x6b901122); /* 13 */
		d = FF (d, a, b, c, x[13],  12, 0xfd987193); /* 14 */
		c = FF (c, d, a, b, x[14],  17, 0xa679438e); /* 15 */
		b = FF (b, c, d, a, x[15],  22, 0x49b40821); /* 16 */

		/* Round 2 */
		a = GG (a, b, c, d, x[ 1],   5, 0xf61e2562); /* 17 */
		d = GG (d, a, b, c, x[ 6],   9, 0xc040b340); /* 18 */
		c = GG (c, d, a, b, x[11],  14, 0x265e5a51); /* 19 */
		b = GG (b, c, d, a, x[ 0],  20, 0xe9b6c7aa); /* 20 */
		a = GG (a, b, c, d, x[ 5],   5, 0xd62f105d); /* 21 */
		d = GG (d, a, b, c, x[10],   9, 0x02441453); /* 22 */
		c = GG (c, d, a, b, x[15],  14, 0xd8a1e681); /* 23 */
		b = GG (b, c, d, a, x[ 4],  20, 0xe7d3fbc8); /* 24 */
		a = GG (a, b, c, d, x[ 9],   5, 0x21e1cde6); /* 25 */
		d = GG (d, a, b, c, x[14],   9, 0xc33707d6); /* 26 */
		c = GG (c, d, a, b, x[ 3],  14, 0xf4d50d87); /* 27 */
		b = GG (b, c, d, a, x[ 8],  20, 0x455a14ed); /* 28 */
		a = GG (a, b, c, d, x[13],   5, 0xa9e3e905); /* 29 */
		d = GG (d, a, b, c, x[ 2],   9, 0xfcefa3f8); /* 30 */
		c = GG (c, d, a, b, x[ 7],  14, 0x676f02d9); /* 31 */
		b = GG (b, c, d, a, x[12],  20, 0x8d2a4c8a); /* 32 */

		/* Round 3 */
		a = HH (a, b, c, d, x[ 5],   4, 0xfffa3942); /* 33 */
		d = HH (d, a, b, c, x[ 8],  11, 0x8771f681); /* 34 */
		c = HH (c, d, a, b, x[11],  16, 0x6d9d6122); /* 35 */
		b = HH (b, c, d, a, x[14],  23, 0xfde5380c); /* 36 */
		a = HH (a, b, c, d, x[ 1],   4, 0xa4beea44); /* 37 */
		d = HH (d, a, b, c, x[ 4],  11, 0x4bdecfa9); /* 38 */
		c = HH (c, d, a, b, x[ 7],  16, 0xf6bb4b60); /* 39 */
		b = HH (b, c, d, a, x[10],  23, 0xbebfbc70); /* 40 */
		a = HH (a, b, c, d, x[13],   4, 0x289b7ec6); /* 41 */
		d = HH (d, a, b, c, x[ 0],  11, 0xeaa127fa); /* 42 */
		c = HH (c, d, a, b, x[ 3],  16, 0xd4ef3085); /* 43 */
		b = HH (b, c, d, a, x[ 6],  23, 0x04881d05); /* 44 */
		a = HH (a, b, c, d, x[ 9],   4, 0xd9d4d039); /* 45 */
		d = HH (d, a, b, c, x[12],  11, 0xe6db99e5); /* 46 */
		c = HH (c, d, a, b, x[15],  16, 0x1fa27cf8); /* 47 */
		b = HH (b, c, d, a, x[ 2],  23, 0xc4ac5665); /* 48 */

		/* Round 4 */
		a = II (a, b, c, d, x[ 0],   6, 0xf4292244); /* 49 */
		d = II (d, a, b, c, x[ 7],  10, 0x432aff97); /* 50 */
		c = II (c, d, a, b, x[14],  15, 0xab9423a7); /* 51 */
		b = II (b, c, d, a, x[ 5],  21, 0xfc93a039); /* 52 */
		a = II (a, b, c, d, x[12],   6, 0x655b59c3); /* 53 */
		d = II (d, a, b, c, x[ 3],  10, 0x8f0ccc92); /* 54 */
		c = II (c, d, a, b, x[10],  15, 0xffeff47d); /* 55 */
		b = II (b, c, d, a, x[ 1],  21, 0x85845dd1); /* 56 */
		a = II (a, b, c, d, x[ 8],   6, 0x6fa87e4f); /* 57 */
		d = II (d, a, b, c, x[15],  10, 0xfe2ce6e0); /* 58 */
		c = II (c, d, a, b, x[ 6],  15, 0xa3014314); /* 59 */
		b = II (b, c, d, a, x[13],  21, 0x4e0811a1); /* 60 */
		a = II (a, b, c, d, x[ 4],   6, 0xf7537e82); /* 61 */
		d = II (d, a, b, c, x[11],  10, 0xbd3af235); /* 62 */
		c = II (c, d, a, b, x[ 2],  15, 0x2ad7d2bb); /* 63 */
		b = II (b, c, d, a, x[ 9],  21, 0xeb86d391); /* 64 */

		state.state[0] += a;
		state.state[1] += b;
		state.state[2] += c;
		state.state[3] += d;
	}
}