package org.python.modules;

/*
 *  Copyright 2011 Gaurav Raje
 *  Licensed to PSF under a Contributor Agreement.
 */

import java.security.MessageDigest;

/**
 * SHA-224 as described in RFC 3874. This introduces the SHA224 Digest which has
 * been omitted from the JDK <code>java.security</code>.
 * <p>
 * This implementation has been borrowed from the Bouncy Castle implementation
 * of SHA2 algorithms.
 * <p>
 * Since they are MIT Licensed, they are compatible with
 * this project. Their mandatory copyright notice follows.
 * <pre>
 * Copyright (c) 2000 - 2011 The Legion Of The Bouncy Castle
 * (http://www.bouncycastle.org)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 * </pre>
 *
 * @deprecated use the SHA224 implementation provided in Java 8 and later
 */
@Deprecated
public class SHA224Digest
        extends MessageDigest {

    private static final int BYTE_LENGTH = 64;
    private byte[] xBuf;
    private int xBufOff;

    private long byteCount;

    @Override
    public void update(
            byte in) {
        xBuf[xBufOff++] = in;

        if (xBufOff == xBuf.length) {
            processWord(xBuf, 0);
            xBufOff = 0;
        }

        byteCount++;
    }

    @Override
    public void update(
            byte[] in,
            int inOff,
            int len) {
        //
        // fill the current word
        //
        while ((xBufOff != 0) && (len > 0)) {
            update(in[inOff]);

            inOff++;
            len--;
        }

        //
        // process whole words.
        //
        while (len > xBuf.length) {
            processWord(in, inOff);

            inOff += xBuf.length;
            len -= xBuf.length;
            byteCount += xBuf.length;
        }

        //
        // load in the remainder.
        //
        while (len > 0) {
            update(in[inOff]);

            inOff++;
            len--;
        }
    }

    public void finish() {
        long bitLength = (byteCount << 3);

        //
        // add the pad bytes.
        //
        update((byte) 128);

        while (xBufOff != 0) {
            update((byte) 0);
        }

        processLength(bitLength);

        processBlock();
    }

    public int getByteLength() {
        return BYTE_LENGTH;
    }

    private static final int DIGEST_LENGTH = 28;

    private int H1, H2, H3, H4, H5, H6, H7, H8;

    private int[] X = new int[64];
    private int xOff;

    /**
     * Standard constructor
     */
    public SHA224Digest() {
        super("SHA-224");
        xBuf = new byte[4];
        xBufOff = 0;
        reset();
    }

    /**
     * Copy constructor. This will copy the state of the provided message
     * digest.
     */
    public SHA224Digest(SHA224Digest t) {
        super("SHA-224");
        xBuf = new byte[t.xBuf.length];
        System.arraycopy(t.xBuf, 0, xBuf, 0, t.xBuf.length);

        xBufOff = t.xBufOff;
        byteCount = t.byteCount;

        H1 = t.H1;
        H2 = t.H2;
        H3 = t.H3;
        H4 = t.H4;
        H5 = t.H5;
        H6 = t.H6;
        H7 = t.H7;
        H8 = t.H8;

        System.arraycopy(t.X, 0, X, 0, t.X.length);
        xOff = t.xOff;
    }

    public String getAlgorithmName() {
        return "SHA-224";
    }

    public int getDigestSize() {
        return DIGEST_LENGTH;
    }

    protected void processWord(
            byte[] in,
            int inOff) {
        // Note: Inlined for performance
        // X[xOff] = Pack.bigEndianToInt(in, inOff);
        int n = in[inOff] << 24;
        n |= (in[++inOff] & 0xff) << 16;
        n |= (in[++inOff] & 0xff) << 8;
        n |= (in[++inOff] & 0xff);
        X[xOff] = n;

        if (++xOff == 16) {
            processBlock();
        }
    }

    protected void processLength(
            long bitLength) {
        if (xOff > 14) {
            processBlock();
        }

        X[14] = (int) (bitLength >>> 32);
        X[15] = (int) (bitLength & 0xffffffff);
    }

    public int doFinal(
            byte[] out,
            int outOff) {
        finish();

        intToBigEndian(H1, out, outOff);
        intToBigEndian(H2, out, outOff + 4);
        intToBigEndian(H3, out, outOff + 8);
        intToBigEndian(H4, out, outOff + 12);
        intToBigEndian(H5, out, outOff + 16);
        intToBigEndian(H6, out, outOff + 20);
        intToBigEndian(H7, out, outOff + 24);

        reset();

        return DIGEST_LENGTH;
    }

    @Override
    public void reset() {
        byteCount = 0;

        xBufOff = 0;
        for (int i = 0; i < xBuf.length; i++) {
            xBuf[i] = 0;
        }

        /*
         * SHA-224 initial hash value
         */

        H1 = 0xc1059ed8;
        H2 = 0x367cd507;
        H3 = 0x3070dd17;
        H4 = 0xf70e5939;
        H5 = 0xffc00b31;
        H6 = 0x68581511;
        H7 = 0x64f98fa7;
        H8 = 0xbefa4fa4;

        xOff = 0;
        for (int i = 0; i != X.length; i++) {
            X[i] = 0;
        }
    }

    protected void processBlock() {
        //
        // expand 16 word block into 64 word blocks.
        //
        for (int t = 16; t <= 63; t++) {
            X[t] = Theta1(X[t - 2]) + X[t - 7] + Theta0(X[t - 15]) + X[t - 16];
        }

        //
        // set up working variables.
        //
        int a = H1;
        int b = H2;
        int c = H3;
        int d = H4;
        int e = H5;
        int f = H6;
        int g = H7;
        int h = H8;

        int t = 0;
        for (int i = 0; i < 8; i++) {
            // t = 8 * i
            h += Sum1(e) + Ch(e, f, g) + K[t] + X[t];
            d += h;
            h += Sum0(a) + Maj(a, b, c);
            ++t;

            // t = 8 * i + 1
            g += Sum1(d) + Ch(d, e, f) + K[t] + X[t];
            c += g;
            g += Sum0(h) + Maj(h, a, b);
            ++t;

            // t = 8 * i + 2
            f += Sum1(c) + Ch(c, d, e) + K[t] + X[t];
            b += f;
            f += Sum0(g) + Maj(g, h, a);
            ++t;

            // t = 8 * i + 3
            e += Sum1(b) + Ch(b, c, d) + K[t] + X[t];
            a += e;
            e += Sum0(f) + Maj(f, g, h);
            ++t;

            // t = 8 * i + 4
            d += Sum1(a) + Ch(a, b, c) + K[t] + X[t];
            h += d;
            d += Sum0(e) + Maj(e, f, g);
            ++t;

            // t = 8 * i + 5
            c += Sum1(h) + Ch(h, a, b) + K[t] + X[t];
            g += c;
            c += Sum0(d) + Maj(d, e, f);
            ++t;

            // t = 8 * i + 6
            b += Sum1(g) + Ch(g, h, a) + K[t] + X[t];
            f += b;
            b += Sum0(c) + Maj(c, d, e);
            ++t;

            // t = 8 * i + 7
            a += Sum1(f) + Ch(f, g, h) + K[t] + X[t];
            e += a;
            a += Sum0(b) + Maj(b, c, d);
            ++t;
        }

        H1 += a;
        H2 += b;
        H3 += c;
        H4 += d;
        H5 += e;
        H6 += f;
        H7 += g;
        H8 += h;

        //
        // reset the offset and clean out the word buffer.
        //
        xOff = 0;
        for (int i = 0; i < 16; i++) {
            X[i] = 0;
        }
    }

    /* SHA-224 functions */
    private int Ch(
            int x,
            int y,
            int z) {
        return ((x & y) ^ ((~x) & z));
    }

    private int Maj(
            int x,
            int y,
            int z) {
        return ((x & y) ^ (x & z) ^ (y & z));
    }

    private int Sum0(
            int x) {
        return ((x >>> 2) | (x << 30)) ^ ((x >>> 13) | (x << 19))
                ^ ((x >>> 22) | (x << 10));
    }

    private int Sum1(
            int x) {
        return ((x >>> 6) | (x << 26)) ^ ((x >>> 11) | (x << 21))
                ^ ((x >>> 25) | (x << 7));
    }

    private int Theta0(
            int x) {
        return ((x >>> 7) | (x << 25)) ^ ((x >>> 18) | (x << 14)) ^ (x >>> 3);
    }

    private int Theta1(
            int x) {
        return ((x >>> 17) | (x << 15)) ^ ((x >>> 19) | (x << 13))
                ^ (x >>> 10);
    }

    /*
     * SHA-224 Constants (represent the first 32 bits of the fractional parts of
     * the cube roots of the first sixty-four prime numbers)
     */
    static final int K[] = {
            0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b,
            0x59f111f1, 0x923f82a4, 0xab1c5ed5,
            0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74,
            0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
            0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f,
            0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
            0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3,
            0xd5a79147, 0x06ca6351, 0x14292967,
            0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354,
            0x766a0abb, 0x81c2c92e, 0x92722c85,
            0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819,
            0xd6990624, 0xf40e3585, 0x106aa070, 0x19a4c116, 0x1e376c08,
            0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f,
            0x682e6ff3,
            0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa,
            0xa4506ceb, 0xbef9a3f7, 0xc67178f2
    };

    @Override
    protected void engineUpdate(byte input) {
        update(input);
    }

    @Override
    protected void engineUpdate(byte[] input, int offset, int len) {
        update(input, offset, len);

    }

    @Override
    protected byte[] engineDigest() {
        byte[] digestBytes = new byte[getDigestSize()];
        doFinal(digestBytes, 0);
        return digestBytes;
    }

    @Override
    protected void engineReset() {
        reset();
    }

    @Override
    public Object clone()
            throws CloneNotSupportedException {
        SHA224Digest d = new SHA224Digest(this);
        return d;
    }

    public static int bigEndianToInt(byte[] bs, int off) {
        int n = bs[off] << 24;
        n |= (bs[++off] & 0xff) << 16;
        n |= (bs[++off] & 0xff) << 8;
        n |= (bs[++off] & 0xff);
        return n;
    }

    public static void intToBigEndian(int n, byte[] bs, int off) {
        bs[off] = (byte) (n >>> 24);
        bs[++off] = (byte) (n >>> 16);
        bs[++off] = (byte) (n >>> 8);
        bs[++off] = (byte) (n);
    }

    public static long bigEndianToLong(byte[] bs, int off) {
        int hi = bigEndianToInt(bs, off);
        int lo = bigEndianToInt(bs, off + 4);
        return ((hi & 0xffffffffL) << 32) | (lo & 0xffffffffL);
    }

    public static void longToBigEndian(long n, byte[] bs, int off) {
        intToBigEndian((int) (n >>> 32), bs, off);
        intToBigEndian((int) (n & 0xffffffffL), bs, off + 4);
    }
}