init: init nachos hw01, should pass jenkins os_group_20_hw job but fail on os_group_20_ta job

code/filesys/pbitmap.cc

@@ -0,0 +1,79 @@
+// pbitmap.c 
+//	Routines to manage a persistent bitmap -- a bitmap that is
+//	stored on disk.
+//
+// Copyright (c) 1992,1993,1995 The Regents of the University of California.
+// All rights reserved.  See copyright.h for copyright notice and limitation 
+// of liability and disclaimer of warranty provisions.
+
+#include "copyright.h"
+#include "pbitmap.h"
+
+//----------------------------------------------------------------------
+// PersistentBitmap::PersistentBitmap(int)
+// 	Initialize a bitmap with "numItems" bits, so that every bit is clear.
+//	it can be added somewhere on a list.
+//
+//	"numItems" is the number of bits in the bitmap.
+//
+//      This constructor does not initialize the bitmap from a disk file
+//----------------------------------------------------------------------
+
+PersistentBitmap::PersistentBitmap(int numItems):Bitmap(numItems) 
+{ 
+}
+
+//----------------------------------------------------------------------
+// PersistentBitmap::PersistentBitmap(OpenFile*,int)
+// 	Initialize a persistent bitmap with "numItems" bits,
+//      so that every bit is clear.
+//
+//	"numItems" is the number of bits in the bitmap.
+//      "file" refers to an open file containing the bitmap (written
+//        by a previous call to PersistentBitmap::WriteBack
+//
+//      This constructor initializes the bitmap from a disk file
+//----------------------------------------------------------------------
+
+PersistentBitmap::PersistentBitmap(OpenFile *file, int numItems):Bitmap(numItems) 
+{ 
+    // map has already been initialized by the BitMap constructor,
+    // but we will just overwrite that with the contents of the
+    // map found in the file
+    file->ReadAt((char *)map, numWords * sizeof(unsigned), 0);
+}
+
+//----------------------------------------------------------------------
+// PersistentBitmap::~PersistentBitmap
+// 	De-allocate a persistent bitmap.
+//----------------------------------------------------------------------
+
+PersistentBitmap::~PersistentBitmap()
+{ 
+}
+
+//----------------------------------------------------------------------
+// PersistentBitmap::FetchFrom
+// 	Initialize the contents of a persistent bitmap from a Nachos file.
+//
+//	"file" is the place to read the bitmap from
+//----------------------------------------------------------------------
+
+void
+PersistentBitmap::FetchFrom(OpenFile *file) 
+{
+    file->ReadAt((char *)map, numWords * sizeof(unsigned), 0);
+}
+
+//----------------------------------------------------------------------
+// PersistentBitmap::WriteBack
+// 	Store the contents of a persistent bitmap to a Nachos file.
+//
+//	"file" is the place to write the bitmap to
+//----------------------------------------------------------------------
+
+void
+PersistentBitmap::WriteBack(OpenFile *file)
+{
+   file->WriteAt((char *)map, numWords * sizeof(unsigned), 0);
+}