/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

package org.apache.tsfile.utils;

import java.util.StringTokenizer;

/**
 * This class is copied from apache lucene, version 8.4.0. Estimates the size(memory representation)
 * of Java objects. <a
 * href="https://github.com/LuXugang/Lucene-7.x-9.x/blob/master/solr-8.4.0/lucene/core/src/java/org/apache/lucene/util/Constants.java">Constants.java</a>
 * Some useful constants.
 */
public final class Constants {

  private Constants() {} // can't construct

  /** JVM vendor info. */
  public static final String JVM_VENDOR = System.getProperty("java.vm.vendor");

  public static final String JVM_VERSION = System.getProperty("java.vm.version");
  public static final String JVM_NAME = System.getProperty("java.vm.name");
  public static final String JVM_SPEC_VERSION = System.getProperty("java.specification.version");

  /** The value of <tt>System.getProperty("java.version")</tt>. * */
  public static final String JAVA_VERSION = System.getProperty("java.version");

  /** The value of <tt>System.getProperty("os.name")</tt>. * */
  public static final String OS_NAME = System.getProperty("os.name");

  /** True iff running on Linux. */
  public static final boolean LINUX = OS_NAME.startsWith("Linux");

  /** True iff running on Windows. */
  public static final boolean WINDOWS = OS_NAME.startsWith("Windows");

  /** True iff running on SunOS. */
  public static final boolean SUN_OS = OS_NAME.startsWith("SunOS");

  /** True iff running on Mac OS X */
  public static final boolean MAC_OS_X = OS_NAME.startsWith("Mac OS X");

  /** True iff running on FreeBSD */
  public static final boolean FREE_BSD = OS_NAME.startsWith("FreeBSD");

  public static final String OS_ARCH = System.getProperty("os.arch");
  public static final String OS_VERSION = System.getProperty("os.version");
  public static final String JAVA_VENDOR = System.getProperty("java.vendor");

  private static final int JVM_MAJOR_VERSION;
  private static final int JVM_MINOR_VERSION;

  /** True iff running on a 64bit JVM */
  public static final boolean JRE_IS_64BIT;

  static {
    final StringTokenizer st = new StringTokenizer(JVM_SPEC_VERSION, ".");
    JVM_MAJOR_VERSION = Integer.parseInt(st.nextToken());
    if (st.hasMoreTokens()) {
      JVM_MINOR_VERSION = Integer.parseInt(st.nextToken());
    } else {
      JVM_MINOR_VERSION = 0;
    }
    boolean is64Bit = false;
    String datamodel = null;
    try {
      datamodel = System.getProperty("sun.arch.data.model");
      if (datamodel != null) {
        is64Bit = datamodel.contains("64");
      }
    } catch (SecurityException ex) {
    }
    if (datamodel == null) {
      if (OS_ARCH != null && OS_ARCH.contains("64")) {
        is64Bit = true;
      } else {
        is64Bit = false;
      }
    }
    JRE_IS_64BIT = is64Bit;
  }

  public static final boolean JRE_IS_MINIMUM_JAVA8 =
      JVM_MAJOR_VERSION > 1 || (JVM_MAJOR_VERSION == 1 && JVM_MINOR_VERSION >= 8);
  public static final boolean JRE_IS_MINIMUM_JAVA9 =
      JVM_MAJOR_VERSION > 1 || (JVM_MAJOR_VERSION == 1 && JVM_MINOR_VERSION >= 9);
  public static final boolean JRE_IS_MINIMUM_JAVA11 =
      JVM_MAJOR_VERSION > 1 || (JVM_MAJOR_VERSION == 1 && JVM_MINOR_VERSION >= 11);
}
