Current File : //usr/lib/calibre/calibre/ebooks/pdb/ereader/writer.py
'''
Write content to ereader pdb file.
'''
__license__ = 'GPL v3'
__copyright__ = '2009, John Schember <john@nachtimwald.com>'
__docformat__ = 'restructuredtext en'
import io
import re
import struct
import zlib
from PIL import Image
from calibre.ebooks.pdb.formatwriter import FormatWriter
from calibre.ebooks.pdb.header import PdbHeaderBuilder
from calibre.ebooks.pml.pmlml import PMLMLizer
from polyglot.builtins import as_bytes
IDENTITY = 'PNRdPPrs'
# This is an arbitrary number that is small enough to work. The actual maximum
# record size is unknown.
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):
pmlmlizer = PMLMLizer(self.log)
pml = str(pmlmlizer.extract_content(oeb_book, self.opts)).encode('cp1252', 'replace')
text, text_sizes = self._text(pml)
chapter_index = self._index_item(br'(?s)\\C(?P<val>[0-4])="(?P<text>.+?)"', pml)
chapter_index += self._index_item(br'(?s)\\X(?P<val>[0-4])(?P<text>.+?)\\X[0-4]', pml)
chapter_index += self._index_item(br'(?s)\\x(?P<text>.+?)\\x', pml)
link_index = self._index_item(br'(?s)\\Q="(?P<text>.+?)"', pml)
images = self._images(oeb_book.manifest, pmlmlizer.image_hrefs)
metadata = [self._metadata(metadata)]
hr = [self._header_record(len(text), len(chapter_index), len(link_index), len(images))]
'''
Record order as generated by Dropbook.
1. eReader Header
2. Compressed text
3. Small font page index
4. Large font page index
5. Chapter index
6. Links index
7. Images
8. (Extrapolation: there should be one more record type here though yet uncovered what it might be).
9. Metadata
10. Sidebar records
11. Footnote records
12. Text block size record
13. "MeTaInFo\x00" word record
'''
sections = hr+text+chapter_index+link_index+images+metadata+[text_sizes]+[b'MeTaInFo\x00']
lengths = [len(i) if i not in images else len(i[0]) + len(i[1]) for i in sections]
pdbHeaderBuilder = PdbHeaderBuilder(IDENTITY, metadata[0].partition(b'\x00')[0])
pdbHeaderBuilder.build_header(lengths, out_stream)
for item in sections:
if item in images:
out_stream.write(item[0])
out_stream.write(item[1])
else:
out_stream.write(item)
def _text(self, pml):
pml_pages = []
text_sizes = b''
index = 0
while index < len(pml):
'''
Split on the space character closest to MAX_RECORD_SIZE when possible.
'''
split = pml.rfind(b' ', index, MAX_RECORD_SIZE)
if split == -1:
len_end = len(pml[index:])
if len_end > MAX_RECORD_SIZE:
split = MAX_RECORD_SIZE
else:
split = len_end
if split == 0:
split = 1
pml_pages.append(zlib.compress(pml[index:index+split]))
text_sizes += struct.pack('>H', split)
index += split
return pml_pages, text_sizes
def _index_item(self, regex, pml):
index = []
for mo in re.finditer(regex, pml):
item = b''
if 'text' in mo.groupdict().keys():
item += struct.pack('>L', mo.start())
text = mo.group('text')
# Strip all PML tags from text
text = re.sub(br'\\U[0-9a-z]{4}', b'', text)
text = re.sub(br'\\a\d{3}', b'', text)
text = re.sub(br'\\.', b'', text)
# Add appropriate spacing to denote the various levels of headings
if 'val' in mo.groupdict().keys():
text = b'%s%s' % (b' ' * 4 * int(mo.group('val')), text)
item += text
item += b'\x00'
if item:
index.append(item)
return index
def _images(self, manifest, image_hrefs):
'''
Image format.
0-4 : 'PNG '. There must be a space after PNG.
4-36 : Image name. Must be exactly 32 bytes long. Pad with \x00 for names shorter than 32 bytes
36-58 : Unknown.
58-60 : Width.
60-62 : Height.
62-...: Raw image data in 8 bit PNG format.
'''
images = []
from calibre.ebooks.oeb.base import OEB_RASTER_IMAGES
for item in manifest:
if item.media_type in OEB_RASTER_IMAGES and item.href in image_hrefs.keys():
try:
im = Image.open(io.BytesIO(item.data)).convert('P')
im.thumbnail((300,300), Image.ANTIALIAS)
data = io.BytesIO()
im.save(data, 'PNG')
data = data.getvalue()
href = as_bytes(image_hrefs[item.href])
header = b'PNG '
header += href.ljust(32, b'\x00')[:32]
header = header.ljust(58, b'\x00')
header += struct.pack('>HH', im.size[0], im.size[1])
header = header.ljust(62, b'\x00')
if len(data) + len(header) < 65505:
images.append((header, data))
except Exception as e:
self.log.error('Error: Could not include file %s because '
'%s.' % (item.href, e))
return images
def _metadata(self, metadata):
'''
Metadata takes the form:
title\x00
author\x00
copyright\x00
publisher\x00
isbn\x00
'''
title = _('Unknown')
author = _('Unknown')
copyright = ''
publisher = ''
isbn = ''
if metadata:
if len(metadata.title) >= 1:
title = metadata.title[0].value
if len(metadata.creator) >= 1:
from calibre.ebooks.metadata import authors_to_string
author = authors_to_string([x.value for x in metadata.creator])
if len(metadata.rights) >= 1:
copyright = metadata.rights[0].value
if len(metadata.publisher) >= 1:
publisher = metadata.publisher[0].value
return as_bytes(f'{title}\x00{author}\x00{copyright}\x00{publisher}\x00{isbn}\x00')
def _header_record(self, text_count, chapter_count, link_count, image_count):
'''
text_count = the number of text pages
image_count = the number of images
'''
compression = 10 # zlib compression.
non_text_offset = text_count + 1
chapter_offset = non_text_offset
link_offset = chapter_offset + chapter_count
if image_count > 0:
image_data_offset = link_offset + link_count
meta_data_offset = image_data_offset + image_count
last_data_offset = meta_data_offset + 1
else:
meta_data_offset = link_offset + link_count
last_data_offset = meta_data_offset + 1
image_data_offset = last_data_offset
if chapter_count == 0:
chapter_offset = last_data_offset
if link_count == 0:
link_offset = last_data_offset
record = b''
record += struct.pack('>H', compression) # [0:2] # Compression. Specifies compression and drm. 2 = palmdoc, 10 = zlib. 260 and 272 = DRM
record += struct.pack('>H', 0) # [2:4] # Unknown.
record += struct.pack('>H', 0) # [4:6] # Unknown.
record += struct.pack('>H', 25152) # [6:8] # 25152 is MAGIC. Somehow represents the cp1252 encoding of the text
record += struct.pack('>H', 0) # [8:10] # Number of small font pages. 0 if page index is not built.
record += struct.pack('>H', 0) # [10:12] # Number of large font pages. 0 if page index is not built.
record += struct.pack('>H', non_text_offset) # [12:14] # Non-Text record start.
record += struct.pack('>H', chapter_count) # [14:16] # Number of chapter index records.
record += struct.pack('>H', 0) # [16:18] # Number of small font page index records.
record += struct.pack('>H', 0) # [18:20] # Number of large font page index records.
record += struct.pack('>H', image_count) # [20:22] # Number of images.
record += struct.pack('>H', link_count) # [22:24] # Number of links.
record += struct.pack('>H', 1) # [24:26] # 1 if has metadata, 0 if not.
record += struct.pack('>H', 0) # [26:28] # Unknown.
record += struct.pack('>H', 0) # [28:30] # Number of Footnotes.
record += struct.pack('>H', 0) # [30:32] # Number of Sidebars.
record += struct.pack('>H', chapter_offset) # [32:34] # Chapter index offset.
record += struct.pack('>H', 2560) # [34:36] # 2560 is MAGIC.
record += struct.pack('>H', last_data_offset) # [36:38] # Small font page offset. This will be the last data offset if there are none.
record += struct.pack('>H', last_data_offset) # [38:40] # Large font page offset. This will be the last data offset if there are none.
record += struct.pack('>H', image_data_offset) # [40:42] # Image offset. This will be the last data offset if there are none.
record += struct.pack('>H', link_offset) # [42:44] # Links offset. This will be the last data offset if there are none.
record += struct.pack('>H', meta_data_offset) # [44:46] # Metadata offset. This will be the last data offset if there are none.
record += struct.pack('>H', 0) # [46:48] # Unknown.
record += struct.pack('>H', last_data_offset) # [48:50] # Footnote offset. This will be the last data offset if there are none.
record += struct.pack('>H', last_data_offset) # [50:52] # Sidebar offset. This will be the last data offset if there are none.
record += struct.pack('>H', last_data_offset) # [52:54] # Last data offset.
for i in range(54, 132, 2):
record += struct.pack('>H', 0) # [54:132]
return record
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