Current File : //usr/lib/calibre/calibre/ebooks/pdb/ztxt/writer.py
'''
Writer content to ztxt pdb file.
'''
__license__ = 'GPL v3'
__copyright__ = '2009, John Schember <john@nachtimwald.com>'
__docformat__ = 'restructuredtext en'
import struct, zlib
from calibre.ebooks.pdb.formatwriter import FormatWriter
from calibre.ebooks.pdb.header import PdbHeaderBuilder
from calibre.ebooks.txt.txtml import TXTMLizer
from calibre.ebooks.txt.newlines import TxtNewlines, specified_newlines
MAX_RECORD_SIZE = 8192
class Writer(FormatWriter):
def __init__(self, opts, log):
self.opts = opts
self.log = log
def write_content(self, oeb_book, out_stream, metadata=None):
title = self.opts.title if self.opts.title else oeb_book.metadata.title[0].value if oeb_book.metadata.title != [] else _('Unknown')
txt_records, txt_length = self._generate_text(oeb_book)
crc32 = 0
section_lengths = []
compressor = zlib.compressobj(9)
self.log.info('Compressing data...')
for i in range(0, len(txt_records)):
self.log.debug('\tCompressing record %i' % i)
txt_records[i] = compressor.compress(txt_records[i])
txt_records[i] = txt_records[i] + compressor.flush(zlib.Z_FULL_FLUSH)
section_lengths.append(len(txt_records[i]))
crc32 = zlib.crc32(txt_records[i], crc32) & 0xffffffff
header_record = self._header_record(txt_length, len(txt_records), crc32)
section_lengths.insert(0, len(header_record))
out_stream.seek(0)
hb = PdbHeaderBuilder('zTXTGPlm', title)
hb.build_header(section_lengths, out_stream)
for record in [header_record]+txt_records:
out_stream.write(record)
def _generate_text(self, oeb_book):
writer = TXTMLizer(self.log)
txt = writer.extract_content(oeb_book, self.opts)
self.log.debug('\tReplacing newlines with selected type...')
txt = specified_newlines(TxtNewlines('windows').newline,
txt).encode(self.opts.pdb_output_encoding, 'replace')
txt_length = len(txt)
txt_records = []
for i in range(0, (len(txt) / MAX_RECORD_SIZE) + 1):
txt_records.append(txt[i * MAX_RECORD_SIZE : (i * MAX_RECORD_SIZE) + MAX_RECORD_SIZE])
return txt_records, txt_length
def _header_record(self, txt_length, record_count, crc32):
record = b''
record += struct.pack('>H', 0x012c) # [0:2], version. 0x012c = 1.44
record += struct.pack('>H', record_count) # [2:4], Number of PDB records used for the text of the book.
record += struct.pack('>L', txt_length) # [4:8], Uncompressed length of the entire text of the book.
record += struct.pack('>H', MAX_RECORD_SIZE) # [8:10], Maximum size of each record containing text
record += struct.pack('>H', 0) # [10:12], Number of bookmarks.
record += struct.pack('>H', 0) # [12:14], Bookmark record. 0 if there are no bookmarks.
record += struct.pack('>H', 0) # [14:16], Number of annotations.
record += struct.pack('>H', 0) # [16:18], Annotation record. 0 if there are no annotations.
record += struct.pack('>B', 1) # [18:19], Flags. Bitmask, 0x01 = Random Access. 0x02 = Non-Uniform text block size.
record += struct.pack('>B', 0) # [19:20], Reserved.
record += struct.pack('>L', crc32) # [20:24], crc32
record += struct.pack('>LL', 0, 0) # [24:32], padding
return record
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