package net.jpountz.util;

/*
 * Copyright 2020 Adrien Grand and the lz4-java contributors.
 *
 * 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.
 */

import java.nio.ByteOrder;

public enum SafeUtils {
  ;

  public static void checkRange(byte[] buf, int off) {
    if (off < 0 || off >= buf.length) {
      throw new ArrayIndexOutOfBoundsException(off);
    }
  }

  public static void checkRange(byte[] buf, int off, int len) {
    checkLength(len);
    if (len > 0) {
      checkRange(buf, off);
      checkRange(buf, off + len - 1);
    }
  }

  public static void checkLength(int len) {
    if (len < 0) {
      throw new IllegalArgumentException("lengths must be >= 0");
    }
  }

  public static byte readByte(byte[] buf, int i) {
    return buf[i];
  }

  public static int readIntBE(byte[] buf, int i) {
    return ((buf[i] & 0xFF) << 24) | ((buf[i+1] & 0xFF) << 16) | ((buf[i+2] & 0xFF) << 8) | (buf[i+3] & 0xFF);
  }

  public static int readIntLE(byte[] buf, int i) {
    return (buf[i] & 0xFF) | ((buf[i+1] & 0xFF) << 8) | ((buf[i+2] & 0xFF) << 16) | ((buf[i+3] & 0xFF) << 24);
  }

  public static int readInt(byte[] buf, int i) {
    if (Utils.NATIVE_BYTE_ORDER == ByteOrder.BIG_ENDIAN) {
      return readIntBE(buf, i);
    } else {
      return readIntLE(buf, i);
    }
  }

  public static long readLongLE(byte[] buf, int i) {
    return (buf[i] & 0xFFL) | ((buf[i+1] & 0xFFL) << 8) | ((buf[i+2] & 0xFFL) << 16) | ((buf[i+3] & 0xFFL) << 24)
         | ((buf[i+4] & 0xFFL) << 32) | ((buf[i+5] & 0xFFL) << 40) | ((buf[i+6] & 0xFFL) << 48) | ((buf[i+7] & 0xFFL) << 56);
  }

  public static void writeShortLE(byte[] buf, int off, int v) {
    buf[off++] = (byte) v;
    buf[off++] = (byte) (v >>> 8);
  }

  public static void writeInt(int[] buf, int off, int v) {
    buf[off] = v;
  }

  public static int readInt(int[] buf, int off) {
    return buf[off];
  }

  public static void writeByte(byte[] dest, int off, int i) {
    dest[off] = (byte) i;
  }

  public static void writeShort(short[] buf, int off, int v) {
    buf[off] = (short) v;
  }

  public static int readShortLE(byte[] buf, int i) {
    return (buf[i] & 0xFF) | ((buf[i+1] & 0xFF) << 8);
  }

  public static int readShort(short[] buf, int off) {
    return buf[off] & 0xFFFF;
  }
}
