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The UnboundID LDAP SDK for Java is a fast, comprehensive, and easy-to-use Java API for communicating with LDAP directory servers and performing related tasks like reading and writing LDIF, encoding and decoding data using base64 and ASN.1 BER, and performing secure communication. This package contains the Commercial Edition of the LDAP SDK, which includes all of the general-purpose functionality contained in the Standard Edition, plus additional functionality specific to UnboundID server products.
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/*
 * Copyright 2007-2017 UnboundID Corp.
 * All Rights Reserved.
 */
/*
 * Copyright (C) 2008-2017 UnboundID Corp.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License (GPLv2 only)
 * or the terms of the GNU Lesser General Public License (LGPLv2.1 only)
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see .
 */
package com.unboundid.asn1;



import com.unboundid.util.NotMutable;
import com.unboundid.util.ThreadSafety;
import com.unboundid.util.ThreadSafetyLevel;

import static com.unboundid.asn1.ASN1Constants.*;
import static com.unboundid.asn1.ASN1Messages.*;
import static com.unboundid.util.Debug.*;



/**
 * This class provides an ASN.1 integer element, whose value may be represented
 * as an integer with up to a 32-bit representation.
 */
@NotMutable()
@ThreadSafety(level=ThreadSafetyLevel.COMPLETELY_THREADSAFE)
public final class ASN1Integer
       extends ASN1Element
{
  /**
   * The serial version UID for this serializable class.
   */
  private static final long serialVersionUID = -733929804601994372L;



  // The int value for this element.
  private final int intValue;



  /**
   * Creates a new ASN.1 integer element with the default BER type and the
   * provided int value.
   *
   * @param  intValue  The int value to use for this element.
   */
  public ASN1Integer(final int intValue)
  {
    super(UNIVERSAL_INTEGER_TYPE, encodeIntValue(intValue));

    this.intValue = intValue;
  }



  /**
   * Creates a new ASN.1 integer element with the specified BER type and the
   * provided int value.
   *
   * @param  type      The BER type to use for this element.
   * @param  intValue  The int value to use for this element.
   */
  public ASN1Integer(final byte type, final int intValue)
  {
    super(type, encodeIntValue(intValue));

    this.intValue = intValue;
  }



  /**
   * Creates a new ASN.1 integer element with the specified BER type and the
   * provided int and pre-encoded values.
   *
   * @param  type      The BER type to use for this element.
   * @param  intValue  The int value to use for this element.
   * @param  value     The pre-encoded value to use for this element.
   */
  private ASN1Integer(final byte type, final int intValue, final byte[] value)
  {
    super(type, value);

    this.intValue = intValue;
  }



  /**
   * Encodes the provided int value to a byte array suitable for use as the
   * value of an integer element.
   *
   * @param  intValue  The int value to be encoded.
   *
   * @return  A byte array containing the encoded value.
   */
  static byte[] encodeIntValue(final int intValue)
  {
    if (intValue < 0)
    {
      if ((intValue & 0xFFFFFF80) == 0xFFFFFF80)
      {
        return new byte[]
        {
          (byte) (intValue & 0xFF)
        };
      }
      else if ((intValue & 0xFFFF8000) == 0xFFFF8000)
      {
        return new byte[]
        {
          (byte) ((intValue >> 8) & 0xFF),
          (byte) (intValue & 0xFF)
        };
      }
      else if ((intValue & 0xFF800000) == 0xFF800000)
      {
        return new byte[]
        {
          (byte) ((intValue >> 16) & 0xFF),
          (byte) ((intValue >> 8) & 0xFF),
          (byte) (intValue & 0xFF)
        };
      }
      else
      {
        return new byte[]
        {
          (byte) ((intValue >> 24) & 0xFF),
          (byte) ((intValue >> 16) & 0xFF),
          (byte) ((intValue >> 8) & 0xFF),
          (byte) (intValue & 0xFF)
        };
      }
    }
    else
    {
      if ((intValue & 0x0000007F) == intValue)
      {
        return new byte[]
        {
          (byte) (intValue & 0x7F)
        };
      }
      else if ((intValue & 0x00007FFF) == intValue)
      {
        return new byte[]
        {
          (byte) ((intValue >> 8) & 0x7F),
          (byte) (intValue & 0xFF)
        };
      }
      else if ((intValue & 0x007FFFFF) == intValue)
      {
        return new byte[]
        {
          (byte) ((intValue >> 16) & 0x7F),
          (byte) ((intValue >> 8) & 0xFF),
          (byte) (intValue & 0xFF)
        };
      }
      else
      {
        return new byte[]
        {
          (byte) ((intValue >> 24) & 0x7F),
          (byte) ((intValue >> 16) & 0xFF),
          (byte) ((intValue >> 8) & 0xFF),
          (byte) (intValue & 0xFF)
        };
      }
    }
  }



  /**
   * Retrieves the int value for this element.
   *
   * @return  The int value for this element.
   */
  public int intValue()
  {
    return intValue;
  }



  /**
   * Decodes the contents of the provided byte array as an integer element.
   *
   * @param  elementBytes  The byte array to decode as an ASN.1 integer element.
   *
   * @return  The decoded ASN.1 integer element.
   *
   * @throws  ASN1Exception  If the provided array cannot be decoded as an
   *                         integer element.
   */
  public static ASN1Integer decodeAsInteger(final byte[] elementBytes)
         throws ASN1Exception
  {
    try
    {
      int valueStartPos = 2;
      int length = (elementBytes[1] & 0x7F);
      if (length != elementBytes[1])
      {
        final int numLengthBytes = length;

        length = 0;
        for (int i=0; i < numLengthBytes; i++)
        {
          length <<= 8;
          length |= (elementBytes[valueStartPos++] & 0xFF);
        }
      }

      if ((elementBytes.length - valueStartPos) != length)
      {
        throw new ASN1Exception(ERR_ELEMENT_LENGTH_MISMATCH.get(length,
                                     (elementBytes.length - valueStartPos)));
      }

      final byte[] value = new byte[length];
      System.arraycopy(elementBytes, valueStartPos, value, 0, length);

      int intValue;
      switch (value.length)
      {
        case 1:
          intValue = (value[0] & 0xFF);
          if ((value[0] & 0x80) != 0x00)
          {
            intValue |= 0xFFFFFF00;
          }
          break;

        case 2:
          intValue = ((value[0] & 0xFF) << 8) | (value[1] & 0xFF);
          if ((value[0] & 0x80) != 0x00)
          {
            intValue |= 0xFFFF0000;
          }
          break;

        case 3:
          intValue = ((value[0] & 0xFF) << 16) | ((value[1] & 0xFF) << 8) |
                     (value[2] & 0xFF);
          if ((value[0] & 0x80) != 0x00)
          {
            intValue |= 0xFF000000;
          }
          break;

        case 4:
          intValue = ((value[0] & 0xFF) << 24) | ((value[1] & 0xFF) << 16) |
                     ((value[2] & 0xFF) << 8) | (value[3] & 0xFF);
          break;

        default:
          throw new ASN1Exception(ERR_ENUMERATED_INVALID_LENGTH.get(
                                       value.length));
      }

      return new ASN1Integer(elementBytes[0], intValue, value);
    }
    catch (final ASN1Exception ae)
    {
      debugException(ae);
      throw ae;
    }
    catch (final Exception e)
    {
      debugException(e);
      throw new ASN1Exception(ERR_ELEMENT_DECODE_EXCEPTION.get(e), e);
    }
  }



  /**
   * Decodes the provided ASN.1 element as an integer element.
   *
   * @param  element  The ASN.1 element to be decoded.
   *
   * @return  The decoded ASN.1 integer element.
   *
   * @throws  ASN1Exception  If the provided element cannot be decoded as an
   *                         integer element.
   */
  public static ASN1Integer decodeAsInteger(final ASN1Element element)
         throws ASN1Exception
  {
    int intValue;
    final byte[] value = element.getValue();
    switch (value.length)
    {
      case 1:
        intValue = (value[0] & 0xFF);
        if ((value[0] & 0x80) != 0x00)
        {
          intValue |= 0xFFFFFF00;
        }
        break;

      case 2:
        intValue = ((value[0] & 0xFF) << 8) | (value[1] & 0xFF);
        if ((value[0] & 0x80) != 0x00)
        {
          intValue |= 0xFFFF0000;
        }
        break;

      case 3:
        intValue = ((value[0] & 0xFF) << 16) | ((value[1] & 0xFF) << 8) |
                   (value[2] & 0xFF);
        if ((value[0] & 0x80) != 0x00)
        {
          intValue |= 0xFF000000;
        }
        break;

      case 4:
        intValue = ((value[0] & 0xFF) << 24) | ((value[1] & 0xFF) << 16) |
                   ((value[2] & 0xFF) << 8) | (value[3] & 0xFF);
        break;

      default:
        throw new ASN1Exception(ERR_INTEGER_INVALID_LENGTH.get(value.length));
    }

    return new ASN1Integer(element.getType(), intValue, value);
  }



  /**
   * Appends a string representation of this ASN.1 element to the provided
   * buffer.
   *
   * @param  buffer  The buffer to which to append the information.
   */
  @Override()
  public void toString(final StringBuilder buffer)
  {
    buffer.append(intValue);
  }
}