Current File : //usr/lib/calibre/calibre/ebooks/pdb/palmdoc/writer.py
'''
Writer content to palmdoc pdb file.
'''
__license__ = 'GPL v3'
__copyright__ = '2009, John Schember <john@nachtimwald.com>'
__docformat__ = 'restructuredtext en'
import struct
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 = 4096
class Writer(FormatWriter):
def __init__(self, opts, log):
self.opts = opts
self.log = log
def write_content(self, oeb_book, out_stream, metadata=None):
from calibre.ebooks.compression.palmdoc import compress_doc
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)
header_record = self._header_record(txt_length, len(txt_records))
section_lengths = [len(header_record)]
self.log.info('Compessing data...')
for i in range(0, len(txt_records)):
self.log.debug('\tCompressing record %i' % i)
txt_records[i] = compress_doc(txt_records[i])
section_lengths.append(len(txt_records[i]))
out_stream.seek(0)
hb = PdbHeaderBuilder('TEXtREAd', 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):
record = b''
record += struct.pack('>H', 2) # [0:2], PalmDoc compression. (1 = No compression).
record += struct.pack('>H', 0) # [2:4], Always 0.
record += struct.pack('>L', txt_length) # [4:8], Uncompressed length of the entire text of the book.
record += struct.pack('>H', record_count) # [8:10], Number of PDB records used for the text of the book.
record += struct.pack('>H', MAX_RECORD_SIZE) # [10-12], Maximum size of each record containing text, always 4096.
record += struct.pack('>L', 0) # [12-16], Current reading position, as an offset into the uncompressed text.
return record
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