-
Notifications
You must be signed in to change notification settings - Fork 0
/
mobi6.py
164 lines (132 loc) · 5.36 KB
/
mobi6.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
#!/usr/bin/env python
# vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:ai
from __future__ import (absolute_import, print_function)
from six.moves import range
__license__ = 'GPL v3'
__copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
__docformat__ = 'restructuredtext en'
try:
load_translations()
except NameError:
pass # load_translations() added in calibre 1.9
import struct
from io import BytesIO
from calibre.ebooks.metadata.mobi import MetadataUpdater
from calibre.ebooks.mobi import MobiError
class TopazError(ValueError):
pass
class FireEXTHHeader(object):
'''
This is an extension of the calibre EXTHHeader class just for the
purposes of getting the cdetype field
'''
def __init__(self, raw):
self.doctype = raw[:4]
self.length, self.num_items = struct.unpack('>LL', raw[4:12])
raw = raw[12:]
pos = 0
left = self.num_items
self.cdetype = ''
self.asin = ''
self.asin2 = ''
self.clipping_limit = None
while left > 0:
left -= 1
idx, size = struct.unpack('>LL', raw[pos:pos + 8])
content = raw[pos + 8:pos + size]
pos += size
if idx == 113:
# asin
self.asin = content
elif idx == 401:
# clippinglimit
self.clipping_limit = ord(content)
elif idx == 501:
# cdetype
self.cdetype = content
elif idx == 504:
# cdetype
self.asin2 = content
class MinimalMobiHeader(object):
def __init__(self, raw, log):
self.log = log
if len(raw) <= 16:
self.exth_flag, self.exth = 0, None
else:
self.exth_flag, = struct.unpack('>L', raw[0x80:0x84])
self.length, self.type, self.codepage, self.unique_id, \
self.version = struct.unpack('>LLLLL', raw[20:40])
self.exth = None
if self.exth_flag & 0x40:
try:
self.exth = FireEXTHHeader(raw[16 + self.length:])
except:
self.log.exception('Invalid EXTH header')
self.exth_flag = 0
class MinimalMobiReader(object):
def __init__(self, filename, log):
self.log = log
stream = open(filename, 'rb')
self.stream = stream
raw = stream.read()
if raw.startswith(b'TPZ'):
raise TopazError(_('This is an Amazon Topaz book. It cannot be processed.'))
self.header = raw[0:72]
self.name = self.header[:32].replace(b'\x00', b'')
self.num_sections, = struct.unpack('>H', raw[76:78])
self.ident = self.header[0x3C:0x3C + 8].upper()
if self.ident not in [b'BOOKMOBI', b'TEXTREAD']:
raise MobiError('Unknown book type: %s' % repr(self.ident))
self.sections = []
self.section_headers = []
for i in range(self.num_sections):
offset, a1, a2, a3, a4 = struct.unpack('>LBBBB', raw[78 + i * 8:78 + i * 8 + 8])
flags, val = a1, a2 << 16 | a3 << 8 | a4
self.section_headers.append((offset, flags, val))
def section(section_number):
if section_number == self.num_sections - 1:
end_off = len(raw)
else:
end_off = self.section_headers[section_number + 1][0]
off = self.section_headers[section_number][0]
return raw[off:end_off]
for i in range(self.num_sections):
self.sections.append((section(i), self.section_headers[i]))
self.book_header = MinimalMobiHeader(self.sections[0][0], self.log)
def __enter__(self):
return self
def __exit__(self, _type, value, traceback):
if self.stream:
self.stream.close()
self.stream = None
class MinimalMobiUpdater(MetadataUpdater):
def update(self, asin=None, cdetype=None):
def update_exth_record(rec):
recs.append(rec)
if rec[0] in self.original_exth_records:
self.original_exth_records.pop(rec[0])
if self.type != b"BOOKMOBI":
raise MobiError("Setting ASIN only supported for MOBI files of type 'BOOK'.\n"
"\tThis is a '%s' file of type '%s'" % (self.type[0:4], self.type[4:8]))
recs = []
if asin is not None:
update_exth_record((113, asin.encode(self.codec, 'replace')))
update_exth_record((504, asin.encode(self.codec, 'replace')))
if cdetype is not None:
update_exth_record((501, cdetype))
# Include remaining original EXTH fields
for id_ in sorted(self.original_exth_records):
recs.append((id_, self.original_exth_records[id_]))
recs = sorted(recs, key=lambda x:(x[0],x[0]))
exth = BytesIO()
for code, data in recs:
exth.write(struct.pack('>II', int(code), len(data) + 8))
exth.write(data)
exth = exth.getvalue()
trail = len(exth) % 4
pad = b'\0' * (4 - trail) # Always pad w/ at least 1 byte
exth = [b'EXTH', struct.pack(b'>II', len(exth) + 12, len(recs)), exth, pad]
exth = b''.join(exth)
if getattr(self, 'exth', None) is None:
raise MobiError(_('No existing EXTH record. Cannot update ASIN.'))
self.create_exth(exth=exth)