package org.ripple.power.utils;

/**
 * 一个MD5的本地实现,方便跨平台移植
 */
public class MD5 {

	private static MD5 _instance;

	public static MD5 get() {
		if (_instance != null) {
			return _instance;
		}
		synchronized (MD5.class) {
			if (_instance == null) {
				_instance = new MD5();
			}
			return _instance;
		}
	}

	final static int S11 = 7;
	final static int S12 = 12;
	final static int S13 = 17;
	final static int S14 = 22;
	final static int S21 = 5;
	final static int S22 = 9;
	final static int S23 = 14;
	final static int S24 = 20;
	final static int S31 = 4;
	final static int S32 = 11;
	final static int S33 = 16;
	final static int S34 = 23;
	final static int S41 = 6;
	final static int S42 = 10;
	final static int S43 = 15;
	final static int S44 = 21;
	final static byte[] PADDING = { -128, 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 };

	private long[] state = new long[4];
	private long[] count = new long[2];
	private byte[] digest = new byte[16];

	public String encryptString(String buffer) {
		md5Init();
		md5Update(buffer.getBytes(), buffer.length());
		md5Final();
		StringBuffer buf = new StringBuffer();
		for (int i = 0; i < 16; i++) {
			buf.append(getByteToHexString(digest[i]));
		}
		return buf.toString();
	}

	public String encryptBytes(byte[] buffer) {
		md5Init();
		md5Update(buffer, buffer.length);
		md5Final();
		StringBuffer buf = new StringBuffer();
		for (int i = 0; i < 16; i++) {
			buf.append(getByteToHexString(digest[i]));
		}
		return buf.toString();
	}

	private MD5() {
		md5Init();
	}

	private void md5Init() {
		count[0] = 0L;
		count[1] = 0L;
		state[0] = 0x67452301L;
		state[1] = 0xefcdab89L;
		state[2] = 0x98badcfeL;
		state[3] = 0x10325476L;
		return;
	}

	private long F(long x, long y, long z) {
		return (x & y) | ((~x) & z);
	}

	private long G(long x, long y, long z) {
		return (x & z) | (y & (~z));
	}

	private long H(long x, long y, long z) {
		return x ^ y ^ z;
	}

	private long I(long x, long y, long z) {
		return y ^ (x | (~z));
	}

	private long FF(long a, long b, long c, long d, long x, long s, long ac) {
		a += F(b, c, d) + x + ac;
		a = ((int) a << s) | ((int) a >>> (32 - s));
		a += b;
		return a;
	}

	private long GG(long a, long b, long c, long d, long x, long s, long ac) {
		a += G(b, c, d) + x + ac;
		a = ((int) a << s) | ((int) a >>> (32 - s));
		a += b;
		return a;
	}

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

	private long II(long a, long b, long c, long d, long x, long s, long ac) {

		a += I(b, c, d) + x + ac;

		a = ((int) a << s) | ((int) a >>> (32 - s));

		a += b;

		return a;
	}

	private void md5Update(byte[] buffer, int inputLen) {

		int i, index, partLen;

		byte[] block = new byte[64];

		index = (int) (count[0] >>> 3) & 0x3F;

		if ((count[0] += (inputLen << 3)) < (inputLen << 3)) {
			count[1]++;
		}
		count[1] += (inputLen >>> 29);

		partLen = 64 - index;

		if (inputLen >= partLen) {

			md5Memcpy(buffer, buffer, index, 0, partLen);

			md5Transform(buffer);

			for (i = partLen; i + 63 < inputLen; i += 64) {

				md5Memcpy(block, buffer, 0, i, 64);

				md5Transform(block);

			}

			index = 0;

		} else {
			i = 0;
		}
		md5Memcpy(buffer, buffer, index, i, inputLen - i);

	}

	private void md5Final() {

		byte[] bits = new byte[8];

		int index, padLen;

		encode(bits, count, 8);

		index = (int) (count[0] >>> 3) & 0x3f;

		padLen = (index < 56) ? (56 - index) : (120 - index);

		md5Update(PADDING, padLen);

		md5Update(bits, 8);

		encode(digest, state, 16);

	}

	private void md5Memcpy(byte[] output, byte[] input, int outpos, int inpos, int len) {
		int i;

		for (i = 0; i < len; i++) {
			output[outpos + i] = input[inpos + i];
		}
	}

	private void md5Transform(byte block[]) {
		long a = state[0], b = state[1], c = state[2], d = state[3];

		long[] x = new long[16];

		decode(x, block, 64);

		/* Round 1 */

		a = FF(a, b, c, d, x[0], S11, 0xd76aa478L); /* 1 */

		d = FF(d, a, b, c, x[1], S12, 0xe8c7b756L); /* 2 */

		c = FF(c, d, a, b, x[2], S13, 0x242070dbL); /* 3 */

		b = FF(b, c, d, a, x[3], S14, 0xc1bdceeeL); /* 4 */

		a = FF(a, b, c, d, x[4], S11, 0xf57c0fafL); /* 5 */

		d = FF(d, a, b, c, x[5], S12, 0x4787c62aL); /* 6 */

		c = FF(c, d, a, b, x[6], S13, 0xa8304613L); /* 7 */

		b = FF(b, c, d, a, x[7], S14, 0xfd469501L); /* 8 */

		a = FF(a, b, c, d, x[8], S11, 0x698098d8L); /* 9 */

		d = FF(d, a, b, c, x[9], S12, 0x8b44f7afL); /* 10 */

		c = FF(c, d, a, b, x[10], S13, 0xffff5bb1L); /* 11 */

		b = FF(b, c, d, a, x[11], S14, 0x895cd7beL); /* 12 */

		a = FF(a, b, c, d, x[12], S11, 0x6b901122L); /* 13 */

		d = FF(d, a, b, c, x[13], S12, 0xfd987193L); /* 14 */

		c = FF(c, d, a, b, x[14], S13, 0xa679438eL); /* 15 */

		b = FF(b, c, d, a, x[15], S14, 0x49b40821L); /* 16 */

		/* Round 2 */

		a = GG(a, b, c, d, x[1], S21, 0xf61e2562L); /* 17 */

		d = GG(d, a, b, c, x[6], S22, 0xc040b340L); /* 18 */

		c = GG(c, d, a, b, x[11], S23, 0x265e5a51L); /* 19 */

		b = GG(b, c, d, a, x[0], S24, 0xe9b6c7aaL); /* 20 */

		a = GG(a, b, c, d, x[5], S21, 0xd62f105dL); /* 21 */

		d = GG(d, a, b, c, x[10], S22, 0x2441453L); /* 22 */

		c = GG(c, d, a, b, x[15], S23, 0xd8a1e681L); /* 23 */

		b = GG(b, c, d, a, x[4], S24, 0xe7d3fbc8L); /* 24 */

		a = GG(a, b, c, d, x[9], S21, 0x21e1cde6L); /* 25 */

		d = GG(d, a, b, c, x[14], S22, 0xc33707d6L); /* 26 */

		c = GG(c, d, a, b, x[3], S23, 0xf4d50d87L); /* 27 */

		b = GG(b, c, d, a, x[8], S24, 0x455a14edL); /* 28 */

		a = GG(a, b, c, d, x[13], S21, 0xa9e3e905L); /* 29 */

		d = GG(d, a, b, c, x[2], S22, 0xfcefa3f8L); /* 30 */

		c = GG(c, d, a, b, x[7], S23, 0x676f02d9L); /* 31 */

		b = GG(b, c, d, a, x[12], S24, 0x8d2a4c8aL); /* 32 */

		/* Round 3 */

		a = HH(a, b, c, d, x[5], S31, 0xfffa3942L); /* 33 */

		d = HH(d, a, b, c, x[8], S32, 0x8771f681L); /* 34 */

		c = HH(c, d, a, b, x[11], S33, 0x6d9d6122L); /* 35 */

		b = HH(b, c, d, a, x[14], S34, 0xfde5380cL); /* 36 */

		a = HH(a, b, c, d, x[1], S31, 0xa4beea44L); /* 37 */

		d = HH(d, a, b, c, x[4], S32, 0x4bdecfa9L); /* 38 */

		c = HH(c, d, a, b, x[7], S33, 0xf6bb4b60L); /* 39 */

		b = HH(b, c, d, a, x[10], S34, 0xbebfbc70L); /* 40 */

		a = HH(a, b, c, d, x[13], S31, 0x289b7ec6L); /* 41 */

		d = HH(d, a, b, c, x[0], S32, 0xeaa127faL); /* 42 */

		c = HH(c, d, a, b, x[3], S33, 0xd4ef3085L); /* 43 */

		b = HH(b, c, d, a, x[6], S34, 0x4881d05L); /* 44 */

		a = HH(a, b, c, d, x[9], S31, 0xd9d4d039L); /* 45 */

		d = HH(d, a, b, c, x[12], S32, 0xe6db99e5L); /* 46 */

		c = HH(c, d, a, b, x[15], S33, 0x1fa27cf8L); /* 47 */

		b = HH(b, c, d, a, x[2], S34, 0xc4ac5665L); /* 48 */

		/* Round 4 */

		a = II(a, b, c, d, x[0], S41, 0xf4292244L); /* 49 */

		d = II(d, a, b, c, x[7], S42, 0x432aff97L); /* 50 */

		c = II(c, d, a, b, x[14], S43, 0xab9423a7L); /* 51 */

		b = II(b, c, d, a, x[5], S44, 0xfc93a039L); /* 52 */

		a = II(a, b, c, d, x[12], S41, 0x655b59c3L); /* 53 */

		d = II(d, a, b, c, x[3], S42, 0x8f0ccc92L); /* 54 */

		c = II(c, d, a, b, x[10], S43, 0xffeff47dL); /* 55 */

		b = II(b, c, d, a, x[1], S44, 0x85845dd1L); /* 56 */

		a = II(a, b, c, d, x[8], S41, 0x6fa87e4fL); /* 57 */

		d = II(d, a, b, c, x[15], S42, 0xfe2ce6e0L); /* 58 */

		c = II(c, d, a, b, x[6], S43, 0xa3014314L); /* 59 */

		b = II(b, c, d, a, x[13], S44, 0x4e0811a1L); /* 60 */

		a = II(a, b, c, d, x[4], S41, 0xf7537e82L); /* 61 */

		d = II(d, a, b, c, x[11], S42, 0xbd3af235L); /* 62 */

		c = II(c, d, a, b, x[2], S43, 0x2ad7d2bbL); /* 63 */

		b = II(b, c, d, a, x[9], S44, 0xeb86d391L); /* 64 */

		state[0] += a;

		state[1] += b;

		state[2] += c;

		state[3] += d;

	}

	private void encode(byte[] output, long[] input, int len) {
		int i, j;
		for (i = 0, j = 0; j < len; i++, j += 4) {
			output[j] = (byte) (input[i] & 0xffL);
			output[j + 1] = (byte) ((input[i] >>> 8) & 0xffL);
			output[j + 2] = (byte) ((input[i] >>> 16) & 0xffL);
			output[j + 3] = (byte) ((input[i] >>> 24) & 0xffL);
		}
	}

	private void decode(long[] output, byte[] input, int len) {
		int i, j;
		for (i = 0, j = 0; j < len; i++, j += 4) {
			output[i] = b2iu(input[j]) | (b2iu(input[j + 1]) << 8) | (b2iu(input[j + 2]) << 16)
					| (b2iu(input[j + 3]) << 24);
		}
		return;
	}

	public long b2iu(byte b) {
		return b < 0 ? b & 0x7F + 128 : b;
	}

	public String getByteToHexString(byte ib) {
		char[] digitNormal = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
		char[] ob = new char[2];
		ob[0] = digitNormal[(ib >>> 4) & 0X0F];
		ob[1] = digitNormal[ib & 0X0F];
		return new String(ob);
	}

	public byte[] makeMD5(byte[] data1, byte[] data2) {
		md5Init();
		md5Update(data1, data1.length);
		md5Update(data2, data2.length);
		md5Final();
		return digest;
	}

}
