Changeset 21396

Timestamp:

2009-12-30T23:52:42+13:00 (13 years ago)

Author:

davidb

Message:

Expanded comment about use of .txt.gz

File:

• main/trunk/greenstone2/common-src/src/lib/gdbmclass.cpp (modified) (1 diff)

main/trunk/greenstone2/common-src/src/lib/gdbmclass.cpp

@@ -286 +286 @@
 
 
-// DEPRECATED -- No longer necessary now that the GDBM library reads both little-endian and big-endian files
+// The following routine was written before the GDBM library was upgraded
+// to read both little-endian and big-endian files, and so the reason for
+// it being developed is not so important now.  It's useful to keep around
+// however because the file format for GDBM is not guaranteed to be the
+// same from one computer architecture to the next.  Even if they are both
+// the same endian-ness.  We encountered this issue on the Mac at one stage.
+// the size of the header data-structure for GDBM was simply a different
+// size to that produced on Linux.  The Mac case resolved to be binary
+// compatabile with Linux, but shows that we can't rely on this always being
+// the case.  Using this method provides a contingency plan.  The databases
+// can be shipped at .txt.gz (i.e. portable), which are then converted on
+// on the host's machine to a native GDBM database that is meaningly to
+// that computer.
+
 void gdbmclass::generate_from_txtgz (text_t filename)
 {