Komihash4_3.java

/*
 * Copyright 2023-2024 Dynatrace LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * This file includes a Java port of the Komihash algorithm originally published
 * at https://github.com/avaneev/komihash under the following license:
 *
 * MIT License
 *
 * Copyright (c) 2021-2023 Aleksey Vaneev
 *
 * 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.
 */
package com.dynatrace.hash4j.hashing;

import static com.dynatrace.hash4j.hashing.UnsignedMultiplyUtil.unsignedMultiplyHigh;

class Komihash4_3 extends AbstractKomihash {

  private static final Hasher64 DEFAULT_HASHER_INSTANCE = create(0L);

  static Hasher64 create() {
    return DEFAULT_HASHER_INSTANCE;
  }

  static Hasher64 create(long useSeed) {
    return new Komihash4_3(useSeed);
  }

  private Komihash4_3(long seed) {
    super(seed);
  }

  @Override
  public HashStream64 hashStream() {
    return new HashStreamImpl();
  }

  @Override
  public long hashBytesToLong(byte[] input, int off, int len) {

    long see1 = this.seed1;
    long see2 = this.seed2;
    long see3 = this.seed3;
    long see4 = this.seed4;
    long see5 = this.seed5;
    long see6 = this.seed6;
    long see7 = this.seed7;
    long see8 = this.seed8;

    boolean nonZeroLength = len > 0;

    if (len > 63) {

      do {

        long tmp1 = see1 ^ getLong(input, off);
        long tmp2 = see5 ^ getLong(input, off + 8);
        long tmp3 = see2 ^ getLong(input, off + 16);
        long tmp4 = see6 ^ getLong(input, off + 24);
        long tmp5 = see3 ^ getLong(input, off + 32);
        long tmp6 = see7 ^ getLong(input, off + 40);
        long tmp7 = see4 ^ getLong(input, off + 48);
        long tmp8 = see8 ^ getLong(input, off + 56);

        see1 = tmp1 * tmp2;
        see5 += unsignedMultiplyHigh(tmp1, tmp2);
        see2 = tmp3 * tmp4;
        see6 += unsignedMultiplyHigh(tmp3, tmp4);
        see3 = tmp5 * tmp6;
        see7 += unsignedMultiplyHigh(tmp5, tmp6);
        see4 = tmp7 * tmp8;
        see8 += unsignedMultiplyHigh(tmp7, tmp8);

        see2 ^= see5;
        see3 ^= see6;
        see4 ^= see7;
        see1 ^= see8;

        off += 64;
        len -= 64;

      } while (len > 63);

      see5 ^= see6 ^ see7 ^ see8;
      see1 ^= see2 ^ see3 ^ see4;
    }

    if (len > 31) {
      long tmp1 = see1 ^ getLong(input, off);
      long tmp2 = see5 ^ getLong(input, off + 8);
      see1 = tmp1 * tmp2;
      see5 += unsignedMultiplyHigh(tmp1, tmp2);
      see1 ^= see5;

      long tmp3 = see1 ^ getLong(input, off + 16);
      long tmp4 = see5 ^ getLong(input, off + 24);
      see1 = tmp3 * tmp4;
      see5 += unsignedMultiplyHigh(tmp3, tmp4);
      see1 ^= see5;
      off += 32;
      len -= 32;
    }

    if (len > 15) {
      long tmp1 = see1 ^ getLong(input, off);
      long tmp2 = see5 ^ getLong(input, off + 8);
      see1 = tmp1 * tmp2;
      see5 += unsignedMultiplyHigh(tmp1, tmp2);
      see1 ^= see5;

      off += 16;
      len -= 16;
    }

    long r2h = see5;
    long r2l = see1;
    int ml8 = len << 3;
    if (len > 7) {
      r2l ^= getLong(input, off);
      long y = getLong(input, off + len - 8);
      long fb = y >>> 1 >>> ~ml8;
      fb |= 1L << ml8 << (y >>> 63);
      r2h ^= fb;
    } else if (len > 3) {
      long fb = getInt(input, off) & 0xFFFFFFFFL;
      long y = getInt(input, off + len - 4);
      fb |= (y << 32) >>> -ml8;
      fb |= 1L << ml8 << (y >>> 63);
      r2l ^= fb;
    } else if (len > 0) {
      long fb = input[off] & 0xFFL;
      if (len > 1) fb |= (input[off + 1] & 0xFFL) << 8;
      if (len > 2) fb |= (input[off + 2] & 0xFFL) << 16;
      fb |= 1L << ml8 << (fb >>> (ml8 - 1));
      r2l ^= fb;
    } else if (nonZeroLength) {
      r2l ^= (input[off - 1] < 0) ? 2L : 1L;
    }

    return finish(r2h, r2l, see5);
  }

  @Override
  public long hashCharsToLong(CharSequence input) {

    int off = 0;
    int len = input.length();

    long see1 = this.seed1;
    long see2 = this.seed2;
    long see3 = this.seed3;
    long see4 = this.seed4;
    long see5 = this.seed5;
    long see6 = this.seed6;
    long see7 = this.seed7;
    long see8 = this.seed8;

    boolean nonZeroLength = len > 0;

    if (len > 31) {

      do {

        long tmp1 = see1 ^ getLong(input, off);
        long tmp2 = see5 ^ getLong(input, off + 4);
        long tmp3 = see2 ^ getLong(input, off + 8);
        long tmp4 = see6 ^ getLong(input, off + 12);
        long tmp5 = see3 ^ getLong(input, off + 16);
        long tmp6 = see7 ^ getLong(input, off + 20);
        long tmp7 = see4 ^ getLong(input, off + 24);
        long tmp8 = see8 ^ getLong(input, off + 28);

        long r1l = tmp1 * tmp2;
        long r1h = unsignedMultiplyHigh(tmp1, tmp2);
        long r2l = tmp3 * tmp4;
        long r2h = unsignedMultiplyHigh(tmp3, tmp4);
        long r3l = tmp5 * tmp6;
        long r3h = unsignedMultiplyHigh(tmp5, tmp6);
        long r4l = tmp7 * tmp8;
        long r4h = unsignedMultiplyHigh(tmp7, tmp8);

        off += 32;
        len -= 32;

        see5 += r1h;
        see6 += r2h;
        see7 += r3h;
        see8 += r4h;
        see2 = see5 ^ r2l;
        see3 = see6 ^ r3l;
        see4 = see7 ^ r4l;
        see1 = see8 ^ r1l;

      } while (len > 31);

      see5 ^= see6 ^ see7 ^ see8;
      see1 ^= see2 ^ see3 ^ see4;
    }

    if (len > 15) {
      long tmp1 = see1 ^ getLong(input, off);
      long tmp2 = see5 ^ getLong(input, off + 4);
      long r1l = tmp1 * tmp2;
      long r1h = unsignedMultiplyHigh(tmp1, tmp2);
      see5 += r1h;
      see1 = see5 ^ r1l;

      long tmp3 = see1 ^ getLong(input, off + 8);
      long tmp4 = see5 ^ getLong(input, off + 12);
      r1l = tmp3 * tmp4;
      r1h = unsignedMultiplyHigh(tmp3, tmp4);
      see5 += r1h;
      see1 = see5 ^ r1l;
      off += 16;
      len -= 16;
    }

    if (len > 7) {
      long tmp1 = see1 ^ getLong(input, off);
      long tmp2 = see5 ^ getLong(input, off + 4);
      long r1l = tmp1 * tmp2;
      long r1h = unsignedMultiplyHigh(tmp1, tmp2);
      see5 += r1h;
      see1 = see5 ^ r1l;

      off += 8;
      len -= 8;
    }

    long r2h = see5;
    long r2l = see1;
    int ml8 = len << 4;
    if (len > 3) {
      r2l ^= getLong(input, off);
      long y = getLong(input, off + len - 4);
      long fb = y >>> 1 >>> ~ml8;
      fb |= 1L << ml8 << (y >>> 63);
      r2h ^= fb;
    } else if (len > 1) {
      long fb = getInt(input, off) & 0xFFFFFFFFL;
      long y = getInt(input, off + len - 2);
      fb |= (y << 32) >>> -ml8;
      fb |= 1L << ml8 << (y >>> 63);
      r2l ^= fb;
    } else if (len > 0) {
      long fb = input.charAt(off);
      fb |= 0x10000L << (fb >>> 15);
      r2l ^= fb;
    } else if (nonZeroLength) {
      r2l ^= 0x1L << ((int) input.charAt(off - 1) >>> 15);
    }

    return finish(r2h, r2l, see5);
  }

  private class HashStreamImpl extends AbstractKomihash.HashStreamImpl {

    @Override
    protected void processBuffer(
        long b0, long b1, long b2, long b3, long b4, long b5, long b6, long b7) {
      b0 ^= see1;
      b1 ^= see5;
      b2 ^= see2;
      b3 ^= see6;
      b4 ^= see3;
      b5 ^= see7;
      b6 ^= see4;
      b7 ^= see8;

      long r1l = b0 * b1;
      long r1h = unsignedMultiplyHigh(b0, b1);
      long r2l = b2 * b3;
      long r2h = unsignedMultiplyHigh(b2, b3);
      long r3l = b4 * b5;
      long r3h = unsignedMultiplyHigh(b4, b5);
      long r4l = b6 * b7;
      long r4h = unsignedMultiplyHigh(b6, b7);

      see5 += r1h;
      see6 += r2h;
      see7 += r3h;
      see8 += r4h;
      see2 = see5 ^ r2l;
      see3 = see6 ^ r3l;
      see4 = see7 ^ r4l;
      see1 = see8 ^ r1l;
    }

    @Override
    protected long finalizeGetAsLong(long se1, long se5, int off, int len) {
      long r2h = se5;
      long r2l = se1;
      long y = 1L << (len << 3);
      long fb = y << ((buffer[(off + len - 1) & 0x3f] < 0) ? 1 : 0);
      if (len > 7) {
        fb |= getLong(buffer, off + 8) & (y - 1);
        r2h ^= fb;
        r2l ^= getLong(buffer, off);
      } else if (byteCount > 0) {
        fb |= getLong(buffer, off) & (y - 1);
        r2l ^= fb;
      }

      return finish(r2h, r2l, se5);
    }

    @Override
    public HashStream64 copy() {
      final HashStreamImpl hashStream = new HashStreamImpl();
      copyTo(hashStream);
      return hashStream;
    }
  }

  @Override
  public long hashLongLongToLong(long v1, long v2) {
    long tmp1 = this.seed1 ^ v1;
    long tmp2 = this.seed5 ^ v2;
    long see5 = unsignedMultiplyHigh(tmp1, tmp2) + this.seed5;
    return finish(see5, (tmp1 * tmp2) ^ (see5 ^ (1L << (v2 >>> 63))), see5);
  }

  @Override
  public long hashLongLongLongToLong(long v1, long v2, long v3) {
    long tmp1 = this.seed1 ^ v1;
    long tmp2 = this.seed5 ^ v2;
    long see5 = unsignedMultiplyHigh(tmp1, tmp2) + this.seed5;
    return finish(see5 ^ (1L << (v3 >>> 63)), (tmp1 * tmp2) ^ (see5 ^ v3), see5);
  }
}