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Support HD image container for some Mobi books
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@choryuidentify
choryuidentify committed Dec 19, 2019
1 parent b71ed38 commit 3b8d615
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23 changes: 23 additions & 0 deletions dedrm_src/k4mobidedrm.py
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Original file line number Diff line number Diff line change
Expand Up @@ -86,12 +86,14 @@ class DrmException(Exception):
from calibre_plugins.dedrm import kgenpids
from calibre_plugins.dedrm import androidkindlekey
from calibre_plugins.dedrm import kfxdedrm
from calibre_plugins.dedrm import mobimergehdimage
else:
import mobidedrm
import topazextract
import kgenpids
import androidkindlekey
import kfxdedrm
import mobimergehdimage

# Wrap a stream so that output gets flushed immediately
# and also make sure that any unicode strings get
Expand Down Expand Up @@ -242,6 +244,27 @@ def GetDecryptedBook(infile, kDatabases, androidFiles, serials, pids, starttime
raise

print u"Decryption succeeded after {0:.1f} seconds".format(time.time()-starttime)

if mobi:
import glob

bookparentpath = os.path.dirname(os.path.abspath(infile))
azwresfiles = glob.glob(bookparentpath + "/*.azw.res")
if azwresfiles != []:
if len(azwresfiles) == 1:
print u"HDImage Container file is found: %s" % os.path.basename(azwresfiles[0])
print u"HDImage merge start..."
try:
hdimage_merger = mobimergehdimage.MobiMergeHDImage(mb.mobi_data)
hdimage_merger.load_azwres(azwresfiles[0])
mb.mobi_data = hdimage_merger.merge()
print u"HDImage merge succeeded after {0:.1f} seconds".format(time.time()-starttime)
except:
print u"Merge failed. Skipping..."
else:
for azwres in azwresfiles:
print u"HDImage Containor is exist more then 1. Skipping..."

return mb


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226 changes: 226 additions & 0 deletions dedrm_src/mobimergehdimage.py
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@@ -0,0 +1,226 @@
#!/usr/bin/env python
# -*- coding: utf-8 -*-

import struct, locale, imghdr, os

#################################################################################
# #
# MOBI HDImage Merger #
# #
# 2019 Choryu Park (Kyoungkyu Park) #
# #
#################################################################################

# This source code is based on these documents, and source codes;
# https://wiki.mobileread.com/wiki/MOBI
# https://wiki.mobileread.com/wiki/PDB
# https://www.mobileread.com/forums/showpost.php?p=3114050&postcount=1145
#
# Thanks to author of 'DumpAZW6'. It many helps to write this source code.

#################################################################################
# * Important; In this source code, First record is 0. not 1.
# So, Last record is Record count - 1.
#
# AZW.RES (HDContainer) Structure ->
# HDContainer is including HD images. each images have own record, and it's Starts with 'CRES'.
# Images is following main book's image ordering, but not include thumbnail.
# and if image not need to HD resolution (like logo, special character), that record marked as 'Placeholder' for matching image count.
#
# -------------------------------
# | Book | HDContainer | Starts with |
# |-------------|-------------- |
# | Image 1 (SD)| HDImage 1 | <- b'CRES'
# | Image 2 | Placeholder | <- b'\xA0\xA0\xA0\xA0'
# | Image 3 (SD)| HDImage 3 | <- b'CRES'
# | Image 4 (SD)| HDImage 4 | <- b'CRES'
# | Thumbnail | *Not exist |
# -------------------------------
# * This structure is sample. Originally, there is no index number.

## Header offsets for Book file
# 2-byte unsigned short
BHDR_OFFSET_NUM_OF_RECORD = 76

# 4-byte unsigned long
BHDR_OFFSET_FILE_IDENT = 60
BHDR_RECORD0_OFFSET_TEXT_ENCODING = 28
BHDR_RECORD0_OFFSET_FULL_NAME_OFFSET = 84
BHDR_RECORD0_OFFSET_FULL_NAME_LENGTH = 88
BHDR_RECORD0_OFFSET_FIRST_IMAGE_INDEX = 108

# 8-byte Record info structure
# - [record Data Offset] 4-byte unsinged long
# - [unused] 4-byte
BHDR_OFFSET_RECORD_INFO_LIST = 78

## Header offsets for HDContainer file
CHDR_OFFSET_FILE_IDENT = 60
CHDR_RECORD0_OFFSET_TEXT_ENCODING = 12
CHDR_RECORD0_OFFSET_FULL_NAME_OFFSET = 40
CHDR_RECORD0_OFFSET_FULL_NAME_LENGTH = 44

TEXT_ENCODING_MAP = {
65001 : "UTF-8",
1252 : "windows-1252"
}

CONTAINER_CONTENT_TYPE_IMAGE = "IMAGE"
CONTAINER_CONTENT_TYPE_PLACEHOLDER = "PLACEHOLDER"

CONTAINER_NEEDED_TYPES = {
b"CRES" : CONTAINER_CONTENT_TYPE_IMAGE,
b"\xa0\xa0\xa0\xa0" : CONTAINER_CONTENT_TYPE_PLACEHOLDER
}

# Actually, this function is grabbed from 'DumpAZW6'. That script can getting from URL where in header of this code.
def get_image_type(imgdata):
imgtype = imghdr.what(None, imgdata)

# horrible hack since imghdr detects jxr/wdp as tiffs
if imgtype is not None and imgtype == "tiff":
imgtype = "wdp"

# imghdr only checks for JFIF or Exif JPEG files. Apparently, there are some
# with only the magic JPEG bytes out there...
# ImageMagick handles those, so, do it too.
if imgtype is None:
if imgdata[0:2] == b'\xFF\xD8':
# Get last non-null bytes
last = len(imgdata)
while (imgdata[last-1:last] == b'\x00'):
last-=1
# Be extra safe, check the trailing bytes, too.
if imgdata[last-2:last] == b'\xFF\xD9':
imgtype = "jpeg"
return imgtype

def get_charset(data, offset):
charset_id, = struct.unpack_from(">L", data, offset)

if charset_id in TEXT_ENCODING_MAP:
return TEXT_ENCODING_MAP[charset_id]
else:
print u"Unknown Charset %d" % charset_id
raise

def get_book_title(data, base_offset, name_offset, length_offset, charset):
name_offset, = struct.unpack_from(">L", data, base_offset + name_offset)
name_length, = struct.unpack_from(">L", data, base_offset + length_offset)
name_offset += base_offset

return data[name_offset:name_offset + name_length].decode(charset)

class MobiMergeHDImage:
hdimage_dict = None

def __init__(self, mobi_data):
self.mobi = mobi_data
self.record_dict = self.get_record_dict(self.mobi)
if self.mobi[BHDR_OFFSET_FILE_IDENT:BHDR_OFFSET_FILE_IDENT+8] != b'BOOKMOBI':
print u"This eBook is not a Mobi."
raise
self.charset = get_charset(self.mobi, self.record_dict[0]["OFFSET"] + BHDR_RECORD0_OFFSET_TEXT_ENCODING)
self.book_title = get_book_title(self.mobi, self.record_dict[0]["OFFSET"], BHDR_RECORD0_OFFSET_FULL_NAME_OFFSET, BHDR_RECORD0_OFFSET_FULL_NAME_LENGTH, self.charset)

def get_record_dict(self, data):
current_offset = BHDR_OFFSET_NUM_OF_RECORD
record_count, = struct.unpack_from(">H", data, current_offset)
record_dict = dict()

record_dict["COUNT"] = record_count

for index in range(0, record_count):
record_dict[index] = dict()

offset = BHDR_OFFSET_RECORD_INFO_LIST + index * 8

record_dict[index]["INFO_OFFSET"] = offset
record_dict[index]["OFFSET"], = struct.unpack_from(">L", data, offset)

return record_dict

def load_azwres(self, res_file):
with open(res_file, 'rb') as azwresfile:
azwres = azwresfile.read()
if azwres[CHDR_OFFSET_FILE_IDENT:CHDR_OFFSET_FILE_IDENT + 8] != b'RBINCONT':
print u"%s is not a HDImage container." % os.path.basename(res_file)
raise

azwres_dict = self.get_record_dict(azwres)

azwres_title = get_book_title(azwres, azwres_dict[0]["OFFSET"], CHDR_RECORD0_OFFSET_FULL_NAME_OFFSET, CHDR_RECORD0_OFFSET_FULL_NAME_LENGTH, self.charset)

if self.book_title != azwres_title:
print u"Book mismatch. Book title and HDImage container title is not same. "
print u"Book: %s, Container: %s" % (self.book_title, azwres_title)
raise

self.hdimage_dict = dict()

image_index = 0
for index, val in sorted(azwres_dict.items()):
if index != "COUNT" and azwres[val["OFFSET"]:val["OFFSET"] + 2] != b"\xe9\x8e":
if azwres[val["OFFSET"]:val["OFFSET"] + 4] in CONTAINER_NEEDED_TYPES:
self.hdimage_dict[image_index] = dict()
self.hdimage_dict[image_index]["INDEX"] = index
self.hdimage_dict[image_index]["TYPE"] = CONTAINER_NEEDED_TYPES[azwres[val["OFFSET"]:val["OFFSET"] + 4]]
if self.hdimage_dict[image_index]["TYPE"] == CONTAINER_CONTENT_TYPE_IMAGE:
self.hdimage_dict[image_index]["CONTENT"] = azwres[val["OFFSET"] + 12:azwres_dict[index + 1]["OFFSET"]]

image_index += 1

def record_offset_update(self, record_index, modified_offset_size):
for target_record_index in range(record_index + 1, self.record_dict["COUNT"]):
self.record_dict[target_record_index]["OFFSET"] = self.record_dict[target_record_index]["OFFSET"] + modified_offset_size
self.mobi = "".join(
(
self.mobi[:self.record_dict[target_record_index]["INFO_OFFSET"]],
struct.pack(">L", self.record_dict[target_record_index]["OFFSET"]),
self.mobi[self.record_dict[target_record_index]["INFO_OFFSET"] + 4:]
)
)

def merge(self):
if self.hdimage_dict is None:
print u"'azw.res' file is not loaded yet."
raise

first_record_offset = self.record_dict[0]['OFFSET']

# Find original book's image
first_image_index, = struct.unpack_from(">L", self.mobi, first_record_offset + 108)

images_dict = dict()
image_index = 0
for record_index in range(first_image_index, self.record_dict["COUNT"]):
if record_index + 1 == self.record_dict["COUNT"]:
img = self.mobi[self.record_dict[record_index]["OFFSET"]:]
else:
img = self.mobi[self.record_dict[record_index]["OFFSET"]:self.record_dict[record_index + 1]["OFFSET"]]

if get_image_type(img) is not None:
images_dict[image_index] = dict()
images_dict[image_index]["INDEX"] = record_index
images_dict[image_index]["CONTENT"] = img
image_index += 1

# Merge
for index, hdimage in self.hdimage_dict.items():
if hdimage["TYPE"] == CONTAINER_CONTENT_TYPE_IMAGE:
# If HDImage type is IMAGE, do merge.
image_offset = self.record_dict[images_dict[index]["INDEX"]]["OFFSET"]

if self.mobi.find(images_dict[index]["CONTENT"]) != -1:
size_difference = len(hdimage["CONTENT"]) - len(images_dict[index]["CONTENT"])

self.mobi = self.mobi.replace(images_dict[index]["CONTENT"], hdimage["CONTENT"])

self.record_offset_update(images_dict[index]["INDEX"], size_difference)

else:
# Skip if it's not a image (Maybe PLACEHOLDER)
pass

return self.mobi

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