tools v1.6

Kindle_Mobi_Tools/lib/mobidedrm.py

@@ -29,8 +29,16 @@
 #  0.13 - Formatting fixes: retabbed file, removed trailing whitespace
 #         and extra blank lines, converted CR/LF pairs at ends of each line,
 #         and other cosmetic fixes.
+#  0.14 - Working out when the extra data flags are present has been problematic
+#         Versions 7 through 9 have tried to tweak the conditions, but have been
+#         only partially successful. Closer examination of lots of sample
+#         files reveals that a confusin has arisen because trailing data entries
+#         are not encrypted, but it turns out that the multibyte entries
+#         in utf8 file are encrypted. (Although neither kind gets compressed.)
+#         This knowledge leads to a simplification of the test for the 
+#         trailing data byte flags - version 5 and higher AND header size >= 0xE4. 
 
-__version__ = '0.13'
+__version__ = '0.14'
 
 import sys
 import struct
@@ -113,8 +121,10 @@ def getSizeOfTrailingDataEntries(ptr, size, flags):
         if testflags & 1:
             num += getSizeOfTrailingDataEntry(ptr, size - num)
         testflags >>= 1
-    if flags & 1:
-        num += (ord(ptr[size - num - 1]) & 0x3) + 1
+    # Multibyte data, if present, is included in the encryption, so
+    # we do not need to check the low bit.
+    # if flags & 1:
+    #    num += (ord(ptr[size - num - 1]) & 0x3) + 1
     return num
 
 class DrmStripper:
@@ -188,7 +198,7 @@ class DrmStripper:
         extra_data_flags = 0
         print "MOBI header length = %d" %mobi_length
         print "MOBI header version = %d" %mobi_version
-        if (mobi_length >= 0xE4) and (mobi_version > 5):
+        if (mobi_length >= 0xE4) and (mobi_version >= 5):
             extra_data_flags, = struct.unpack('>H', sect[0xF2:0xF4])
             print "Extra Data Flags = %d" %extra_data_flags
 
@@ -236,7 +246,7 @@ if not __name__ == "__main__":
         description         = 'Removes DRM from secure Mobi files'
         supported_platforms = ['linux', 'osx', 'windows'] # Platforms this plugin will run on
         author              = 'The Dark Reverser' # The author of this plugin
-        version             = (0, 1, 2)   # The version number of this plugin
+        version             = (0, 1, 4)   # The version number of this plugin
         file_types          = set(['prc','mobi','azw']) # The file types that this plugin will be applied to
         on_import           = True # Run this plugin during the import