[Freevo-devel] [mmpython][patch] Patch that generates unique disc ids based on md5

[Wayne A. Hogue II]

I have run into the problem of most of my discs that I have burned have 
the same name and or creation date.  This leads to many discs having the 
same ID.  After reading the list I see many have the same problem.

Here is a patch that uses the first few bytes of the disc and generates 
a MD5 digest from that data.  My tests using over 100 discs all with 
same volume and and date generated unique ids.   You may find a pair of 
discs that contain different data that generate the same ID, but the 
likelihood of it    is much lower that the old way of generating the IDs.

-Wayne


Index: discinfo.py
===================================================================
RCS file: /cvsroot/mmpython/mmpython/disc/discinfo.py,v
retrieving revision 1.18
diff -u -d -r1.18 discinfo.py
--- discinfo.py 7 Nov 2003 09:43:40 -0000       1.18
+++ discinfo.py 7 Jan 2004 22:17:35 -0000
@@ -95,6 +95,7 @@
 import re
 import time
 import array
+import md5
 from struct import *

@@ -193,7 +194,7 @@

 id_cache = {}

-def cdrom_disc_id(device, handle_mix=0):
+def cdrom_disc_id(device):
     """
     return the disc id of the device or None if no disc is there
     """
@@ -204,16 +205,16 @@
     except:
         pass

-    disc_type = cdrom_disc_status(device, handle_mix=handle_mix)
+    disc_type = cdrom_disc_status(device)
     if disc_type == 0 or disc_type == 3:
         return 0, None

-    elif disc_type == 1 or disc_type == 4:
+    elif disc_type == 1:
         disc_id = DiscID.disc_id(device)
         id = '%08lx_%d' % (disc_id[0], disc_id[1])
     else:
         f = open(device,'rb')
-
+        """
         f.seek(0x0000832d)
         if os.uname()[0] == 'FreeBSD':
             # why doesn't seeking to 0x0000832d+40 and reading 32 work?
@@ -231,7 +232,13 @@
         else:
             label = f.read(32)
         f.close()
-
+        """
+    id = f.read(51200)
+    f.seek(32808,0)
+    label = f.read(32)
+    id_md5 = md5.new()
+    id_md5.update(id)
+    id = id_md5.hexdigest()
         m = re.match("^(.*[^ ]) *$", label)
         if m:
             id = '%s%s' % (id, m.group(1))