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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * accompanied this code).

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package sun.security.provider;

import static sun.security.provider.ByteArrayAccess.*;

import java.nio.*;

import java.util.*;

import java.security.*;

/**

 * This class implements the Secure Hash Algorithm SHA-3 developed by

 * the National Institute of Standards and Technology along with the

 * National Security Agency as defined in FIPS PUB 202.

 *

 * <p>It implements java.security.MessageDigestSpi, and can be used

 * through Java Cryptography Architecture (JCA), as a pluggable

 * MessageDigest implementation.

 *

 * @since       9

 * @author      Valerie Peng

 */

abstract class SHA3 extends DigestBase {

    private static final int WIDTH = 200; // in bytes, e.g. 1600 bits

    private static final int DM = 5; // dimension of lanes

    private static final int NR = 24; // number of rounds

    // precomputed round constants needed by the step mapping Iota

    private static final long[] RC_CONSTANTS = {

        0x01L, 0x8082L, 0x800000000000808aL,

        0x8000000080008000L, 0x808bL, 0x80000001L,

        0x8000000080008081L, 0x8000000000008009L, 0x8aL,

        0x88L, 0x80008009L, 0x8000000aL,

        0x8000808bL, 0x800000000000008bL, 0x8000000000008089L,

        0x8000000000008003L, 0x8000000000008002L, 0x8000000000000080L,

        0x800aL, 0x800000008000000aL, 0x8000000080008081L,

        0x8000000000008080L, 0x80000001L, 0x8000000080008008L,

    };

    private byte[] state = new byte[WIDTH];

    private final long[] lanes = new long[DM*DM];

    /**

     * Creates a new SHA-3 object.

     */

    SHA3(String name, int digestLength) {

        super(name, digestLength, (WIDTH - (2 * digestLength)));

    }

    /**

     * Core compression function. Processes blockSize bytes at a time

     * and updates the state of this object.

     */

    void implCompress(byte[] b, int ofs) {

        for (int i = 0; i < buffer.length; i++) {

            state[i] ^= b[ofs++];

        }

        keccak();

    }

    /**

     * Return the digest. Subclasses do not need to reset() themselves,

     * DigestBase calls implReset() when necessary.

     */

    void implDigest(byte[] out, int ofs) {

        int numOfPadding =

            setPaddingBytes(buffer, (int)(bytesProcessed % buffer.length));

        if (numOfPadding < 1) {

            throw new ProviderException("Incorrect pad size: " + numOfPadding);

        }

        for (int i = 0; i < buffer.length; i++) {

            state[i] ^= buffer[i];

        }

        keccak();

        System.arraycopy(state, 0, out, ofs, engineGetDigestLength());

    }

    /**

     * Resets the internal state to start a new hash.

     */

    void implReset() {

        Arrays.fill(state, (byte)0);

        Arrays.fill(lanes, 0L);

    }

    /**

     * Utility function for padding the specified data based on the

     * pad10*1 algorithm (section 5.1) and the 2-bit suffix "01" required

     * for SHA-3 hash (section 6.1).

     */

    private static int setPaddingBytes(byte[] in, int len) {

        if (len != in.length) {

            // erase leftover values

            Arrays.fill(in, len, in.length, (byte)0);

            // directly store the padding bytes into the input

            // as the specified buffer is allocated w/ size = rateR

            in[len] |= (byte) 0x06;

            in[in.length - 1] |= (byte) 0x80;

        }

        return (in.length - len);

    }

    /**

     * Utility function for transforming the specified byte array 's'

     * into array of lanes 'm' as defined in section 3.1.2.

     */

    private static void bytes2Lanes(byte[] s, long[] m) {

        int sOfs = 0;

        // Conversion traverses along x-axis before y-axis

        for (int y = 0; y < DM; y++, sOfs += 40) {

            b2lLittle(s, sOfs, m, DM*y, 40);

        }

    }

    /**

     * Utility function for transforming the specified array of

     * lanes 'm' into a byte array 's' as defined in section 3.1.3.

     */

    private static void lanes2Bytes(long[] m, byte[] s) {

        int sOfs = 0;

        // Conversion traverses along x-axis before y-axis

        for (int y = 0; y < DM; y++, sOfs += 40) {

            l2bLittle(m, DM*y, s, sOfs, 40);

        }

    }

    /**

     * Step mapping Theta as defined in section 3.2.1 .

     */

    private static long[] smTheta(long[] a) {

        long c0 = a[0]^a[5]^a[10]^a[15]^a[20];

        long c1 = a[1]^a[6]^a[11]^a[16]^a[21];

        long c2 = a[2]^a[7]^a[12]^a[17]^a[22];

        long c3 = a[3]^a[8]^a[13]^a[18]^a[23];

        long c4 = a[4]^a[9]^a[14]^a[19]^a[24];

        long d0 = c4 ^ Long.rotateLeft(c1, 1);

        long d1 = c0 ^ Long.rotateLeft(c2, 1);

        long d2 = c1 ^ Long.rotateLeft(c3, 1);

        long d3 = c2 ^ Long.rotateLeft(c4, 1);

        long d4 = c3 ^ Long.rotateLeft(c0, 1);

        for (int y = 0; y < a.length; y += DM) {

            a[y] ^= d0;

            a[y+1] ^= d1;

            a[y+2] ^= d2;

            a[y+3] ^= d3;

            a[y+4] ^= d4;

        }

        return a;

    }

    /**

     * Merged Step mapping Rho (section 3.2.2) and Pi (section 3.2.3).

     * for performance. Optimization is achieved by precalculating

     * shift constants for the following loop

     *   int xNext, yNext;

     *   for (int t = 0, x = 1, y = 0; t <= 23; t++, x = xNext, y = yNext) {

     *        int numberOfShift = ((t + 1)*(t + 2)/2) % 64;

     *        a[y][x] = Long.rotateLeft(a[y][x], numberOfShift);

     *        xNext = y;

     *        yNext = (2 * x + 3 * y) % DM;

     *   }

     * and with inplace permutation.

     */

    private static long[] smPiRho(long[] a) {

        long tmp = Long.rotateLeft(a[10], 3);

        a[10] = Long.rotateLeft(a[1], 1);

        a[1] = Long.rotateLeft(a[6], 44);

        a[6] = Long.rotateLeft(a[9], 20);

        a[9] = Long.rotateLeft(a[22], 61);

        a[22] = Long.rotateLeft(a[14], 39);

        a[14] = Long.rotateLeft(a[20], 18);

        a[20] = Long.rotateLeft(a[2], 62);

        a[2] = Long.rotateLeft(a[12], 43);

        a[12] = Long.rotateLeft(a[13], 25);

        a[13] = Long.rotateLeft(a[19], 8);

        a[19] = Long.rotateLeft(a[23], 56);

        a[23] = Long.rotateLeft(a[15], 41);

        a[15] = Long.rotateLeft(a[4], 27);

        a[4] = Long.rotateLeft(a[24], 14);

        a[24] = Long.rotateLeft(a[21], 2);

        a[21] = Long.rotateLeft(a[8], 55);

        a[8] = Long.rotateLeft(a[16], 45);

        a[16] = Long.rotateLeft(a[5], 36);

        a[5] = Long.rotateLeft(a[3], 28);

        a[3] = Long.rotateLeft(a[18], 21);

        a[18] = Long.rotateLeft(a[17], 15);

        a[17] = Long.rotateLeft(a[11], 10);

        a[11] = Long.rotateLeft(a[7], 6);

        a[7] = tmp;

        return a;

    }

    /**

     * Step mapping Chi as defined in section 3.2.4.

     */

    private static long[] smChi(long[] a) {

        for (int y = 0; y < a.length; y+=DM) {

            long ay0 = a[y];

            long ay1 = a[y+1];

            long ay2 = a[y+2];

            long ay3 = a[y+3];

            long ay4 = a[y+4];

            a[y] = ay0 ^ ((~ay1) & ay2);

            a[y+1] = ay1 ^ ((~ay2) & ay3);

            a[y+2] = ay2 ^ ((~ay3) & ay4);

            a[y+3] = ay3 ^ ((~ay4) & ay0);

            a[y+4] = ay4 ^ ((~ay0) & ay1);

        }

        return a;

    }

    /**

     * Step mapping Iota as defined in section 3.2.5.

     */

    private static long[] smIota(long[] a, int rndIndex) {

        a[0] ^= RC_CONSTANTS[rndIndex];

        return a;

    }

    /**

     * The function Keccak as defined in section 5.2 with

     * rate r = 1600 and capacity c = (digest length x 2).

     */

    private void keccak() {

        // convert the 200-byte state into 25 lanes

        bytes2Lanes(state, lanes);

        // process the lanes through step mappings

        for (int ir = 0; ir < NR; ir++) {

            smIota(smChi(smPiRho(smTheta(lanes))), ir);

        }

        // convert the resulting 25 lanes back into 200-byte state

        lanes2Bytes(lanes, state);

    }

    public Object clone() throws CloneNotSupportedException {

        SHA3 copy = (SHA3) super.clone();

        copy.state = copy.state.clone();

        return copy;

    }

    /**

     * SHA3-224 implementation class.

     */

    public static final class SHA224 extends SHA3 {

        public SHA224() {

            super("SHA3-224", 28);

        }

    }

    /**

     * SHA3-256 implementation class.

     */

    public static final class SHA256 extends SHA3 {

        public SHA256() {

            super("SHA3-256", 32);

        }

    }

    /**

     * SHAs-384 implementation class.

     */

    public static final class SHA384 extends SHA3 {

        public SHA384() {

            super("SHA3-384", 48);

        }

    }

    /**

     * SHA3-512 implementation class.

     */

    public static final class SHA512 extends SHA3 {

        public SHA512() {

            super("SHA3-512", 64);

        }

    }

}