Class posix.CPtr

All Packages  This Package  Class Hierarchy  Class Search  Index

Class posix.CPtr

java.lang.Object
   |
   +----posix.CPtr

Summary

public class  CPtr
     extends java.lang.Object
{
          // Fields 10
     public static final int CBYTE_TYPE;
     public static final int CDBL_TYPE;
     public static final int CFLT_TYPE;
     public static final int CINT_TYPE;
     public static final int CLONG_TYPE;
     public static final int CPTR_TYPE;
     public static final int CSHORT_TYPE;
     static final long NULL;
     long addr;
     int size;

          // Constructors 2
     CPtr();
     CPtr(long, int);

          // Methods 18
     public static native int alignOf(int);
     public static native int sizeOf(int);

     public native void copyIn(int, byte[], int, int);
     public native void copyOut(int, byte[], int, int);
     public native byte getByte(int);
     public int getCInt(int);
     public native int getCInt(int, int);
     public short getCShort(int);
     public native short getCShort(int, int);
     public native int getInt(int);
     public native short getShort(int);
     public native void setByte(int, byte);
     public void setCInt(int, int);
     public native void setCInt(int, int, int);
     public native void setCShort(int, int, short);
     public void setCShort(int, short);
     public native void setInt(int, int);
     public native void setShort(int, short);

          // Inner Classes 1
     public static class CPtr.Struct
}

Read and write memory reachable through a C ptr. Memory access is bounds checked to keep it within the size of region addressed by the C ptr. Only classes within the posix package can create CPtr objects, and the use of this class is completely safe at present. This is because we know the size of, for instance, shared memory segments or memory allocated with C malloc. At some future date, we may need the ability to dereference arbitrary C pointers - those dereferences will be unsafe.

We have not yet implemented the floating and 64-bit types for get/set due to a lack of need.

Author:

This code is distributed under the GNU Library General Public License

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This library 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 Library General Public License for more details.

You should have received a copy of the GNU Library General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

Cross Reference

Extended By:: Malloc
Returned By:: SharedMem.attach()

Fields