def _parse_exth_header (raw):
exth = Storage()
exth.identifier, \
exth.header_length, \
exth.record_count, \
= struct.unpack('>4sLL', raw[:12])
exthdata = raw[12:]
pos = 0
records = []
records_left = exth.record_count
while records_left > 0:
records_left -= 1
record = Storage()
record.type, \
record.length, \
= struct.unpack('>LL', exthdata[pos:pos + 8])
record.data = exthdata[pos+8:pos+record.length]
pos += record.length
records.append(record)
exth.records = records
return exth
def _parse_mobi_header (raw):
mobiheader = Storage()
mobiheader.compression, \
_unused, \
mobiheader.text_length, \
mobiheader.record_count, \
mobiheader.record_size, \
mobiheader.encryption, \
_unknown, \
= struct.unpack('>HHLHHHH', raw[0:0x10])
# Some ancient MOBI files have no more metadata than this
if len(raw) <= 16:
return mobiheader
mobiheader.identifier, \
mobiheader.header_length, \
mobiheader.mobi_type, \
mobiheader.text_encoding, \
mobiheader.unique_id, \
mobiheader.file_version, \
mobiheader.ortographic_index_record, \
mobiheader.inflection_index_record, \
mobiheader.index_names_record, \
mobiheader.index_keys_record, \
mobiheader.extra_index0_record, \
mobiheader.extra_index1_record, \
mobiheader.extra_index2_record, \
mobiheader.extra_index3_record, \
mobiheader.extra_index4_record, \
mobiheader.extra_index5_record, \
mobiheader.first_nonbook_record, \
mobiheader.fullname_offset, \
mobiheader.fullname_length, \
mobiheader.locale, \
mobiheader.dictionary_input_language, \
mobiheader.dictionary_output_language, \
mobiheader.min_version, \
mobiheader.first_image_record, \
mobiheader.huffman_record, \
mobiheader.huffman_record_count, \
mobiheader.huffman_table_record, \
mobiheader.huffman_table_length, \
mobiheader.exth_flags, \
= struct.unpack('>4sLLLLLLLLLLLLLLLLLLLLLLLLLLLL', raw[0x10:0x84])
if len(raw) >= 0xb4:
mobiheader.drm_offset, \
mobiheader.drm_count, \
mobiheader.drm_size, \
mobiheader.drm_flags, \
= struct.unpack('>LLLL', raw[0xa4:0xb4])
if mobiheader.header_length < 0xe4 or \
mobiheader.header_length > 0xf8:
mobiheader.extra_flags = 0
else:
mobiheader.extra_flags, = struct.unpack('>H', raw[0xf2:0xf4])
fullname_end = mobiheader.fullname_offset + mobiheader.fullname_length
if fullname_end < len(raw):
mobiheader.fullname = raw[mobiheader.fullname_offset:fullname_end]
else:
mobiheader.fullname = None
if mobiheader.exth_flags & 0x40:
mobiheader.exth = _parse_exth_header(raw[16 + mobiheader.header_length:])
return mobiheader
