Added another tool used in dak (and placed nowhere else), dsync

[dak.git] / tools / dsync-0.0 / libdsync / contrib / slidingwindow.h

diff --git a/tools/dsync-0.0/libdsync/contrib/slidingwindow.h b/tools/dsync-0.0/libdsync/contrib/slidingwindow.h
new file mode 100644 (file)
index 0000000..40a7875
--- /dev/null
+++ b/tools/dsync-0.0/libdsync/contrib/slidingwindow.h
@@ -0,0 +1,57 @@
+// -*- mode: cpp; mode: fold -*-
+// Description                                                         /*{{{*/
+// $Id: slidingwindow.h,v 1.2 1999/11/15 07:59:49 jgg Exp $
+/* ######################################################################
+   
+   Sliding Window - Implements a sliding buffer over a file. 
+   
+   The buffer can be of arbitary size and where possible mmap is used
+   to optimize IO.
+   
+   To use, init the class and then call Extend with a 0 input pointer
+   to receive the first block and then call extend with Start <= End 
+   to get the next block. If Start != End then Start will be returned
+   with a new value, but pointing at the same byte, that is the new
+   region will contain the subregion Start -> End(o) but with a new
+   length End-Start, End != End(o).
+   
+   After the file has been exhausted Start == End will be returned, but
+   the old region Start -> End(o) will remain valid.
+   
+   ##################################################################### */
+                                                                       /*}}}*/
+#ifndef SLIDING_WINDOW_H
+#define SLIDING_WINDOW_H
+
+#ifdef __GNUG__
+#pragma interface "dsync/slidingwindow.h"
+#endif 
+
+#include <sys/types.h>
+#include <dsync/fileutl.h>
+
+class SlidingWindow
+{
+   unsigned char *Buffer;
+   unsigned long Size;
+   unsigned long MinSize;
+   FileFd &Fd;
+   unsigned long PageSize;
+   off_t Offset;
+   off_t Left;
+   
+   inline unsigned long Align(off_t V) const {return ((V % PageSize) == 0)?V:V + PageSize - (V % PageSize);};
+   inline unsigned long Align(unsigned long V) const {return ((V % PageSize) == 0)?V:V + PageSize - (V % PageSize);};
+   inline unsigned long AlignDn(off_t V) const {return ((V % PageSize) == 0)?V:V - (V % PageSize);};
+   inline unsigned long AlignDn(unsigned long V) const {return ((V % PageSize) == 0)?V:V - (V % PageSize);};
+   
+   public:
+
+   // Make the distance Start - End longer if possible
+   bool Extend(unsigned char *&Start,unsigned char *&End);
+   
+   SlidingWindow(FileFd &Fd,unsigned long MinSize = 0);
+   ~SlidingWindow();
+};
+
+#endif