md5.java

聊天源码

		a += (b ^ c ^ d) + x[1] + 0xa4beea44; /* 37 */
		a = ((a << 4) | (a >>> 28)) + b;
		d += (a ^ b ^ c) + x[4] + 0x4bdecfa9; /* 38 */
		d = ((d << 11) | (d >>> 21)) + a;
		c += (d ^ a ^ b) + x[7] + 0xf6bb4b60; /* 39 */
		c = ((c << 16) | (c >>> 16)) + d;
		b += (c ^ d ^ a) + x[10] + 0xbebfbc70; /* 40 */
		b = ((b << 23) | (b >>> 9)) + c;

		a += (b ^ c ^ d) + x[13] + 0x289b7ec6; /* 41 */
		a = ((a << 4) | (a >>> 28)) + b;
		d += (a ^ b ^ c) + x[0] + 0xeaa127fa; /* 42 */
		d = ((d << 11) | (d >>> 21)) + a;
		c += (d ^ a ^ b) + x[3] + 0xd4ef3085; /* 43 */
		c = ((c << 16) | (c >>> 16)) + d;
		b += (c ^ d ^ a) + x[6] + 0x04881d05; /* 44 */
		b = ((b << 23) | (b >>> 9)) + c;

		a += (b ^ c ^ d) + x[9] + 0xd9d4d039; /* 33 */
		a = ((a << 4) | (a >>> 28)) + b;
		d += (a ^ b ^ c) + x[12] + 0xe6db99e5; /* 34 */
		d = ((d << 11) | (d >>> 21)) + a;
		c += (d ^ a ^ b) + x[15] + 0x1fa27cf8; /* 35 */
		c = ((c << 16) | (c >>> 16)) + d;
		b += (c ^ d ^ a) + x[2] + 0xc4ac5665; /* 36 */
		b = ((b << 23) | (b >>> 9)) + c;

		/* Round 4 */
		a += (c ^ (b | ~d)) + x[0] + 0xf4292244; /* 49 */
		a = ((a << 6) | (a >>> 26)) + b;
		d += (b ^ (a | ~c)) + x[7] + 0x432aff97; /* 50 */
		d = ((d << 10) | (d >>> 22)) + a;
		c += (a ^ (d | ~b)) + x[14] + 0xab9423a7; /* 51 */
		c = ((c << 15) | (c >>> 17)) + d;
		b += (d ^ (c | ~a)) + x[5] + 0xfc93a039; /* 52 */
		b = ((b << 21) | (b >>> 11)) + c;

		a += (c ^ (b | ~d)) + x[12] + 0x655b59c3; /* 53 */
		a = ((a << 6) | (a >>> 26)) + b;
		d += (b ^ (a | ~c)) + x[3] + 0x8f0ccc92; /* 54 */
		d = ((d << 10) | (d >>> 22)) + a;
		c += (a ^ (d | ~b)) + x[10] + 0xffeff47d; /* 55 */
		c = ((c << 15) | (c >>> 17)) + d;
		b += (d ^ (c | ~a)) + x[1] + 0x85845dd1; /* 56 */
		b = ((b << 21) | (b >>> 11)) + c;

		a += (c ^ (b | ~d)) + x[8] + 0x6fa87e4f; /* 57 */
		a = ((a << 6) | (a >>> 26)) + b;
		d += (b ^ (a | ~c)) + x[15] + 0xfe2ce6e0; /* 58 */
		d = ((d << 10) | (d >>> 22)) + a;
		c += (a ^ (d | ~b)) + x[6] + 0xa3014314; /* 59 */
		c = ((c << 15) | (c >>> 17)) + d;
		b += (d ^ (c | ~a)) + x[13] + 0x4e0811a1; /* 60 */
		b = ((b << 21) | (b >>> 11)) + c;

		a += (c ^ (b | ~d)) + x[4] + 0xf7537e82; /* 61 */
		a = ((a << 6) | (a >>> 26)) + b;
		d += (b ^ (a | ~c)) + x[11] + 0xbd3af235; /* 62 */
		d = ((d << 10) | (d >>> 22)) + a;
		c += (a ^ (d | ~b)) + x[2] + 0x2ad7d2bb; /* 63 */
		c = ((c << 15) | (c >>> 17)) + d;
		b += (d ^ (c | ~a)) + x[9] + 0xeb86d391; /* 64 */
		b = ((b << 21) | (b >>> 11)) + c;

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

	/**
	 * Updates hash with the bytebuffer given (using at maximum length bytes
	 * from that buffer)
	 * 
	 * @param stat
	 *            Which state is updated
	 * @param buffer
	 *            Array of bytes to be hashed
	 * @param offset
	 *            Offset to buffer array
	 * @param length
	 *            Use at maximum `length' bytes (absolute maximum is
	 *            buffer.length)
	 */
	private final void update(MD5State stat, byte buffer[], int offset, int length) {
		int index, partlen, i, start;
		finals = null;
		/* Length can be told to be shorter, but not inter */
		if ((length - offset) > buffer.length)
			length = buffer.length - offset;

		/* compute number of bytes mod 64 */

		index = (int) (stat.count & 0x3f);
		stat.count += length;

		partlen = 64 - index;

		if (length >= partlen) {
			// update state (using only Java) to reflect input
			int[] decode_buf = new int[16];
			if (partlen == 64) {
				partlen = 0;
			} else {
				for (i = 0; i < partlen; i++)
					stat.buffer[i + index] = buffer[i + offset];
				transform(stat, stat.buffer, 0, decode_buf);
			}
			for (i = partlen; (i + 63) < length; i += 64) {
				transform(stat, buffer, i + offset, decode_buf);
			}
			index = 0;
		} else
			i = 0;
		/* buffer remaining input */
		if (i < length) {
			start = i;
			for (; i < length; i++) {
				stat.buffer[index + i - start] = buffer[i + offset];
			}
		}
	}
	
	private static final byte[] encode( final int input[], final int len) {
		int i, j;
		byte out[];
		out = new byte[len];
		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;
	}

	public MD5( byte[] data ) {
		state = new MD5State();
		finals = null;
		update( data );
	}
	
	/**
	 * Updates hash with given array of bytes
	 * 
	 * @param buffer
	 *            Array of bytes to use for updating the hash
	 */
	public final void update( final byte buffer[]) {
		if( buffer == null )
			return;
		this.state = new MD5State();
		update( state, buffer,0, buffer.length );
	}

	/**
	 * Returns array of bytes (16 bytes) representing hash as of the current
	 * state of this object. Note: getting a hash does not invalidate the hash
	 * object, it only creates a copy of the real state which is finalized.
	 * 
	 * @return Array of 16 bytes, the hash of all updated bytes
	 */
	public synchronized final byte[] doFinal() {
		byte bits[];
		int index, padlen;
		MD5State fin;
		if (finals == null) {
			fin = new MD5State(state);
			int[] count_ints = { (int) (fin.count << 3),(int) (fin.count >> 29) };
			bits = encode(count_ints, 8);
			index = (int) (fin.count & 0x3f);
			padlen = (index < 56) ? (56 - index) : (120 - index);
			update(fin, padding, 0, padlen);
			update(fin, bits, 0, 8);
			/* Update() sets finals to null */
			finals = fin;
		}

		return encode(finals.state, 16);
	}

	/**
	 * Returns 32-character hex representation of this objects hash
	 * 
	 * @return String of this object's hash
	 */
	public static final String toHex( final byte[] hash ) {
		char buf[] = new char[hash.length * 2];
		for (int i = 0, x = 0; i < hash.length; i++) {
			buf[x++] = HEX_CHARS[(hash[i] >>> 4) & 0xf];
			buf[x++] = HEX_CHARS[hash[i] & 0xf];
		}
		return new String(buf);
	}

	public static final String toBase64( final byte[] data ) {
		char[] alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=".toCharArray();
		char[] out = new char[((data.length + 2) / 3) * 4];
		for (int i=0, index=0; i<data.length; i+=3, index+=4) {
	        boolean quad = false;
	        boolean trip = false;

	        int val = (0xFF & data[i]);
	        val <<= 8;
	        if ((i+1) < data.length) {
	            val |= (0xFF & data[i+1]);
	            trip = true;
	        }
	        val <<= 8;
	        if ((i+2) < data.length) {
	            val |= (0xFF & data[i+2]);
	            quad = true;
	        }
	        out[index+3] = alphabet[(quad? (val & 0x3F): 64)];
	        val >>= 6;
	        out[index+2] = alphabet[(trip? (val & 0x3F): 64)];
	        val >>= 6;
	        out[index+1] = alphabet[val & 0x3F];
	        val >>= 6;
	        out[index+0] = alphabet[val & 0x3F];
	    }
	    return new String( out );
	}

	/**
	 * Calculates and returns the hash of the contents of the given file.
	 */
	public final byte[] fingerprint(final byte[] data) {
		update( data ); 
		return doFinal();
	}

	/**
	 * @return true iff the first 16 bytes of both hash1 and hash2 are equal;
	 *         both hash1 and hash2 are null; or either hash array is less than
	 *         16 bytes in length and their lengths and all of their bytes are
	 *         equal.
	 */
	public static final boolean equals(byte[] hash1, byte[] hash2) {
		if (hash1 == null)
			return hash2 == null;
		if (hash2 == null)
			return false;
		int targ = 16;
		if (hash1.length < 16) {
			if (hash2.length != hash1.length)
				return false;
			targ = hash1.length;
		} else if (hash2.length < 16) {
			return false;
		}
		for (int i = 0; i < targ; i++) {
			if (hash1[i] != hash2[i])
				return false;
		}
		return true;
	}
}