2004-07-17 Mark Wielaard <mark@klomp.org>

	* gnu/java/nio/channels/FileChannelImpl.java (truncate): Only truncate
	when size is smaller.
	* java/io/RandomAccessFile.java (setLength): Use truncate for
	shrinking the file and seek plus write for expanding the file.

2004-07-17  Michael Koch  <konqueror@gmx.de>

	* gnu/java/nio/channels/natFileChannelPosix.cc
	(implTruncate): Always save current position. Only reposition file
	pointer to where we started if not beyond new lenght. Reposition file
	pointer to file length if it points beyond the end of file.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@84868 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 21 insertions, 7 deletions

diff --git a/libjava/java/io/RandomAccessFile.java b/libjava/java/io/RandomAccessFile.java
index c20549c12df..7907d46f2fd 100644
--- a/libjava/java/io/RandomAccessFile.java
+++ b/libjava/java/io/RandomAccessFile.java
@@ -194,12 +194,14 @@ public class RandomAccessFile implements DataOutput, DataInput
   }
 
   /**
-   * This method sets the length of the file to the specified length.  If
-   * the currently length of the file is longer than the specified length,
-   * then the file is truncated to the specified length.  If the current
-   * length of the file is shorter than the specified length, the file
-   * is extended with bytes of an undefined value.
-   *  <p>
+   * This method sets the length of the file to the specified length.
+   * If the currently length of the file is longer than the specified
+   * length, then the file is truncated to the specified length (the
+   * file position is set to the end of file in this case).  If the
+   * current length of the file is shorter than the specified length,
+   * the file is extended with bytes of an undefined value (the file
+   * position is unchanged in this case).
+   * <p>
    * The file must be open for write access for this operation to succeed.
    *
    * @param newlen The new length of the file
@@ -208,7 +210,19 @@ public class RandomAccessFile implements DataOutput, DataInput
    */
   public void setLength (long newLen) throws IOException
   {
-    ch.truncate (newLen);
+    // FIXME: Extending a file should probably be done by one method call.
+
+    // FileChannel.truncate() can only shrink a file.
+    // To expand it we need to seek forward and write at least one byte.
+    if (newLen < length())
+      ch.truncate (newLen);
+    else if (newLen > length())
+      {
+	long pos = getFilePointer();
+	seek(newLen - 1);
+	write(0);
+	seek(pos);
+      }
   }
 
   /**