Initial revision

From-SVN: r102075

libjava/classpath/vm/reference/java/lang/VMSystem.java

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+/* VMSystem.java -- helper for java.lang.system
+   Copyright (C) 1998, 2002, 2004 Free Software Foundation
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath 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 GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+package java.lang;
+
+import java.io.BufferedInputStream;
+import java.io.BufferedOutputStream;
+import java.io.FileDescriptor;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.InputStream;
+import java.io.PrintStream;
+
+/**
+ * VMSystem is a package-private helper class for System that the
+ * VM must implement.
+ *
+ * @author John Keiser
+ */
+final class VMSystem
+{
+  /**
+   * Copy one array onto another from <code>src[srcStart]</code> ...
+   * <code>src[srcStart+len-1]</code> to <code>dest[destStart]</code> ...
+   * <code>dest[destStart+len-1]</code>. First, the arguments are validated:
+   * neither array may be null, they must be of compatible types, and the
+   * start and length must fit within both arrays. Then the copying starts,
+   * and proceeds through increasing slots.  If src and dest are the same
+   * array, this will appear to copy the data to a temporary location first.
+   * An ArrayStoreException in the middle of copying will leave earlier
+   * elements copied, but later elements unchanged.
+   *
+   * @param src the array to copy elements from
+   * @param srcStart the starting position in src
+   * @param dest the array to copy elements to
+   * @param destStart the starting position in dest
+   * @param len the number of elements to copy
+   * @throws NullPointerException if src or dest is null
+   * @throws ArrayStoreException if src or dest is not an array, if they are
+   *         not compatible array types, or if an incompatible runtime type
+   *         is stored in dest
+   * @throws IndexOutOfBoundsException if len is negative, or if the start or
+   *         end copy position in either array is out of bounds
+   */
+  static native void arraycopy(Object src, int srcStart,
+                               Object dest, int destStart, int len);
+
+  /**
+   * Get a hash code computed by the VM for the Object. This hash code will
+   * be the same as Object's hashCode() method.  It is usually some
+   * convolution of the pointer to the Object internal to the VM.  It
+   * follows standard hash code rules, in that it will remain the same for a
+   * given Object for the lifetime of that Object.
+   *
+   * @param o the Object to get the hash code for
+   * @return the VM-dependent hash code for this Object
+   */
+  static native int identityHashCode(Object o);
+
+  /**
+   * Convert a library name to its platform-specific variant.
+   *
+   * @param libname the library name, as used in <code>loadLibrary</code>
+   * @return the platform-specific mangling of the name
+   * @XXX Add this method
+  static native String mapLibraryName(String libname);
+   */
+
+  /**
+   * Set {@link #in} to a new InputStream.
+   *
+   * @param in the new InputStream
+   * @see #setIn(InputStream)
+   */
+  static native void setIn(InputStream in);
+
+  /**
+   * Set {@link #out} to a new PrintStream.
+   *
+   * @param out the new PrintStream
+   * @see #setOut(PrintStream)
+   */
+  static native void setOut(PrintStream out);
+
+  /**
+   * Set {@link #err} to a new PrintStream.
+   *
+   * @param err the new PrintStream
+   * @see #setErr(PrintStream)
+   */
+  static native void setErr(PrintStream err);
+
+  /**
+   * Get the current time, measured in the number of milliseconds from the
+   * beginning of Jan. 1, 1970. This is gathered from the system clock, with
+   * any attendant incorrectness (it may be timezone dependent).
+   *
+   * @return the current time
+   * @see java.util.Date
+   */
+   public static native long currentTimeMillis();
+
+  /**
+   * Helper method which creates the standard input stream.
+   * VM implementors may choose to construct these streams differently.
+   * This method can also return null if the stream is created somewhere 
+   * else in the VM startup sequence.
+   */
+
+    static InputStream makeStandardInputStream()
+    {
+	return new BufferedInputStream(new FileInputStream(FileDescriptor.in));
+    }
+
+  /**
+   * Helper method which creates the standard output stream.
+   * VM implementors may choose to construct these streams differently.
+   * This method can also return null if the stream is created somewhere 
+   * else in the VM startup sequence.
+   */
+
+    static PrintStream makeStandardOutputStream()
+    {
+	return new PrintStream(new BufferedOutputStream(new FileOutputStream(FileDescriptor.out)), true);
+    }
+  /**
+   * Helper method which creates the standard error stream.
+   * VM implementors may choose to construct these streams differently.
+   * This method can also return null if the stream is created somewhere 
+   * else in the VM startup sequence.
+   */
+
+    static PrintStream makeStandardErrorStream()
+    {
+	return new PrintStream(new BufferedOutputStream(new FileOutputStream(FileDescriptor.err)), true);
+    }
+
+  /**
+   * Gets the value of an environment variable.
+   * Always returning null is a valid (but not very useful) implementation.
+   *
+   * @param name The name of the environment variable (will not be null).
+   * @return The string value of the variable or null when the
+   *         environment variable is not defined.
+   */
+  static native String getenv(String name);
+}