making RandomAccessStream use seek(long)

Posted by Mario Emmenlauer-3 on Aug 16, 2007; 11:32pm
URL: http://imagej.273.s1.nabble.com/making-RandomAccessStream-use-seek-long-tp3698555.html

Hi all,

I was working on extending the LSM Toolbox
(http://imagejdocu.tudor.lu/Members/ppirrotte/lsmtoolbox)
to be able to read Zeiss LSM files of more than 4GB filesize. For
that it would be good if the RandomAccessStream class would use
long (64bit) pointers for file offsets, especially for seek().
Below patch solved the issue for me, however I didn't check
if it's completely sane.

BTW: I was surprised to see seek(int) anyways, especially since
java nowadays uses long. Is it a remainder from old times or did
I overlook anything?

Cheers,

    Mario



--- RandomAccessStream.java 2007-08-16 23:45:02.000000000 +0200
+++ myRandomAccessStream.java 2007-08-16 23:48:06.000000000 +0200
@@ -1,3 +1,4 @@
+package ij.io;
  import java.io.*;
  import java.util.Vector;

@@ -15,7 +16,7 @@

      private InputStream src;
      private RandomAccessFile ras;
-    private int pointer;
+    private long pointer;
      private Vector data;
      private int length;
      private boolean foundEOS;
@@ -35,7 +36,7 @@
          this.ras = ras;
      }

-    public int getFilePointer() throws IOException {
+    public long getFilePointer() throws IOException {
          if (ras!=null)
              return (int)ras.getFilePointer();
          else
@@ -45,8 +46,8 @@
      public int read() throws IOException {
          if (ras!=null)
              return ras.read();
-        int l = pointer + 1;
-        int l1 = readUntil(l);
+        long l = pointer + 1;
+        long l1 = readUntil(l);
          if(l1 >= l) {
              byte abyte0[] = (byte[])data.elementAt((int)(pointer>>BLOCK_SHIFT));
              return abyte0[(int)(pointer++ & BLOCK_MASK)] & 0xff;
@@ -63,7 +64,7 @@
              throw new IndexOutOfBoundsException();
          if(len == 0)
              return 0;
-        int l = readUntil(pointer+len);
+        long l = readUntil(pointer+len);
          if(l<=pointer)
              return -1;
          else {
@@ -88,7 +89,7 @@
          } while (read<len);
      }

-    private int readUntil(int l) throws IOException {
+    private long readUntil(long l) throws IOException {
          if(l<length)
              return l;
          if(foundEOS)
@@ -116,10 +115,10 @@
          return length;
      }

-    public void seek(int loc) throws IOException {
+    public void seek(long loc) throws IOException {
          //if (ij.IJ.debugMode) ij.IJ.log("seek: "+loc);
          if (ras!=null)
-            {ras.seek(loc&0xffffffff); return;}
+            {ras.seek(loc); return;}
          if(loc < 0)
              pointer = 0;
          else


--
Mario Emmenlauer                             Phone: [phone]
Institute for Computer Science               Fax:   [phone]
Chair of Pattern Recognition and Image Processing
Albert-Ludwigs-University
Georges-Koehler-Allee 052, room 01-022
79110 Freiburg             mailto:emmenlau * informatik.uni-freiburg.de
Germany          http://lmb.informatik.uni-freiburg.de/people/emmenlau/