From a97a8a44a84221a5f5907926c83cbc98b9d7426e Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Sat, 29 Mar 2014 12:59:37 +0530
Subject: [PATCH] Properly identify huffman records in MOBI header

---
 src/calibre/ebooks/mobi/debug/headers.py | 4 ++--
 src/calibre/ebooks/mobi/writer8/mobi.py  | 5 ++---
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/src/calibre/ebooks/mobi/debug/headers.py b/src/calibre/ebooks/mobi/debug/headers.py
index c40f418369..6dddfc8184 100644
--- a/src/calibre/ebooks/mobi/debug/headers.py
+++ b/src/calibre/ebooks/mobi/debug/headers.py
@@ -427,8 +427,8 @@ class MOBIHeader(object):  # {{{
         r('First Image index', 'first_image_index')
         r('Huffman record offset', 'huffman_record_offset')
         a('Huffman record count: %d'%self.huffman_record_count)
-        r('DATP record offset', 'datp_record_offset')
-        a('DATP record count: %r'%self.datp_record_count)
+        r('Huffman table offset', 'datp_record_offset')
+        a('Huffman table length: %r'%self.datp_record_count)
         a('EXTH flags: %s (%s)'%(bin(self.exth_flags)[2:], self.has_exth))
         if self.has_drm_data:
             a('Unknown3: %r'%self.unknown3)
diff --git a/src/calibre/ebooks/mobi/writer8/mobi.py b/src/calibre/ebooks/mobi/writer8/mobi.py
index 36402bbc10..891f45f58c 100644
--- a/src/calibre/ebooks/mobi/writer8/mobi.py
+++ b/src/calibre/ebooks/mobi/writer8/mobi.py
@@ -116,9 +116,8 @@ class MOBIHeader(Header):  # {{{
     # 112: Huff/CDIC compression
     huff_first_record
     huff_count
-
-    # 120: Unknown (Maybe DATP related, maybe HUFF/CDIC related)
-    maybe_datp = zeroes(8)
+    huff_table_offset = zeroes(4)
+    huff_table_length = zeroes(4)
 
     # 128: EXTH flags
     exth_flags = DYN