com.ibm.as400.access.IFSQuerySpaceRep Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of jt400 Show documentation
The Open Source version of the IBM Toolbox for Java
The newest version!
///////////////////////////////////////////////////////////////////////////////
//                                                                             
// JTOpen (IBM Toolbox for Java - OSS version)                              
//                                                                             
// Filename: IFSQuerySpaceRep.java
//                                                                             
// The source code contained herein is licensed under the IBM Public License   
// Version 1.0, which has been approved by the Open Source Initiative.         
// Copyright (C) 1997-2004 International Business Machines Corporation and     
// others. All rights reserved.                                                
//                                                                             
///////////////////////////////////////////////////////////////////////////////

package com.ibm.as400.access;

import java.io.IOException;
import java.io.InputStream;

/**
Query available file system space reply.
**/
class IFSQuerySpaceRep extends IFSDataStream
{
  // Special value that is returned by the system the Total Space field, indicating "no maximum".
  private static final long NO_MAX = 0x7FFFFFFFL;

  private static final int UNIT_SIZE_OFFSET = 22;
  private static final int TOTAL_SPACE_OFFSET = 26;
  private static final int SPACE_AVAILABLE_OFFSET = 30;

/**
Construct a query available file system space reply.
**/
  IFSQuerySpaceRep()
  {
  }

/**
Generate a new instance of this type.
@return a reference to the new instance
**/
  public Object getNewDataStream()
  {
    return new IFSQuerySpaceRep();
  }

/**
Return the space available (in bytes).
@return the available space (in bytes)
Returns special value Long.MAX_VALUE if the system reports "no maximum size".
(The File Server returns a bogus value in the Space Available field in that case.)
**/
  long getSpaceAvailable()
  {
    // Previously used get32bit(), but get32bit() incorrectly treated the 4 byte field 
    // as a 4-byte signed value.  On large systems, where the most significant bit was
    // set (in the IFSQuerySpaceRep response), we were returning a negative value.
    // BinaryConverter.byteArrayToUnsignedInt() treats the data as unsigned.

    long totalSpace = BinaryConverter.byteArrayToUnsignedInt(data_, TOTAL_SPACE_OFFSET);
    long spaceAvail = BinaryConverter.byteArrayToUnsignedInt(data_, SPACE_AVAILABLE_OFFSET);
    long unitSize = BinaryConverter.byteArrayToUnsignedInt(data_, UNIT_SIZE_OFFSET);

    // Note: According to the PWSI Datastream Spec:
    // "The value 0x7FFFFFFF is returned to indicate there is no maximum size for the Total Space and Space Available fields."
    if (totalSpace == NO_MAX) return Long.MAX_VALUE;  // no maximum storage limit
    else return (unitSize * spaceAvail);
  }

/**
Return the total space (in bytes).
@return the total space (in bytes)
Returns special value Long.MAX_VALUE if the system reports "no maximum size".
**/
  long getTotalSpace()
  {
    long totalSpace = BinaryConverter.byteArrayToUnsignedInt(data_, TOTAL_SPACE_OFFSET);
    long unitSize = BinaryConverter.byteArrayToUnsignedInt(data_, UNIT_SIZE_OFFSET);

    // Note: According to the PWSI Datastream Spec:
    // "The value 0x7FFFFFFF is returned to indicate there is no maximum size for the Total Space and Space Available fields."
    if (totalSpace == NO_MAX) return Long.MAX_VALUE;  // no maximum storage limit
    else return (unitSize * totalSpace);
  }

/**
Generates a hash code for this data stream.
@return the hash code
**/
  public int hashCode()
  {
    return 0x8007;
  }
}