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https://github.com/kovidgoyal/calibre.git
synced 2025-07-09 03:04:10 -04:00
Greatly improved decoding of metadata block in LRF files. We now handle the incorrectly encoded metadata blocks produced by makelrf 0.3 by assuming a latin1 encoding. Also added additional fields and support for creating a field that does not exist. Metadata blocks are now always written correctly encoded in utf-16 independent of the encoding of the original metadata block.
This commit is contained in:
Kovid Goyal
parent
c25865e76b
commit
cead54c959
@ -27,15 +27,13 @@ to get and set meta information. For example:
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import struct
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import array
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import zlib
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import StringIO
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import xml.dom.minidom as dom
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from xml.dom.ext import Print
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from libprs500.prstypes import field
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BYTE = "<B" #: Unsigned char little endian encoded in 1 byte
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WORD = "<H" #: Unsigned short little endian encoded in 2 bytes
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DWORD = "<I" #: Unsigned integer little endian encoded in 4 bytes
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BYTE = "<B" #: Unsigned char little endian encoded in 1 byte
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WORD = "<H" #: Unsigned short little endian encoded in 2 bytes
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DWORD = "<I" #: Unsigned integer little endian encoded in 4 bytes
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QWORD = "<Q" #: Unsigned long long little endian encoded in 8 bytes
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class versioned_field(field):
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@ -90,37 +88,69 @@ class xml_field(object):
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"""
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Descriptor that gets and sets XML based meta information from an LRF file.
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Works for simple XML fields of the form <tagname>data</tagname>
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"""
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def __init__(self, tag_name):
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""" @param tag_name: The XML tag whoose data we operate on """
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"""
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def __init__(self, tag_name, parent="BookInfo"):
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"""
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@param tag_name: The XML tag whose data we operate on
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@param parent: The tagname of the parent element of C{tag_name}
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"""
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self.tag_name = tag_name
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self.parent = parent
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def __get__(self, obj, typ=None):
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""" Return the data in this field or '' if the field is empty """
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document = dom.parseString(obj.info)
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elem = document.getElementsByTagName(self.tag_name)[0]
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elem.normalize()
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if not elem.hasChildNodes():
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return ""
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return elem.firstChild.data.strip()
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elems = document.getElementsByTagName(self.tag_name)
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if len(elems):
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elem = None
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for candidate in elems:
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if candidate.parentNode.nodeName == self.parent:
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elem = candidate
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if elem:
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elem.normalize()
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if elem.hasChildNodes():
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return elem.firstChild.data.strip()
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return ""
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def __set__(self, obj, val):
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document = dom.parseString(obj.info)
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elem = document.getElementsByTagName(self.tag_name)[0]
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elem.normalize()
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while elem.hasChildNodes():
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elem.removeChild(elem.lastChild)
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elem.appendChild(dom.Text())
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def create_elem():
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elem = document.createElement(self.tag_name)
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elem.appendChild(dom.Text())
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parent = document.getElementsByTagName(self.parent)[0]
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parent.appendChild(elem)
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return elem
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if not val:
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val = u''
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if type(val).__name__ != 'unicode':
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val = unicode(val, 'utf-8')
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elems = document.getElementsByTagName(self.tag_name)
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elem = None
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if len(elems):
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for candidate in elems:
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if candidate.parentNode.nodeName == self.parent:
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elem = candidate
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if not elem:
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elem = create_elem()
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else:
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elem.normalize()
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while elem.hasChildNodes():
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elem.removeChild(elem.lastChild)
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elem.appendChild(dom.Text())
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else:
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elem = create_elem()
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elem.firstChild.data = val
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s = StringIO.StringIO()
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Print(document, s)
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obj.info = s.getvalue()
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s.close()
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info = document.toxml(encoding='utf-16')
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obj.info = info
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def __str__(self):
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return self.tag_name
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def __repr__(self):
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return "XML Field: " + self.tag_name
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return "XML Field: " + self.tag_name + " in " + self.parent
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class LRFMetaFile(object):
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""" Has properties to read and write all Meta information in a LRF file. """
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@ -128,36 +158,39 @@ class LRFMetaFile(object):
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LRF_HEADER = u'LRF'.encode('utf-16')[2:]+'\0\0'
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lrf_header = fixed_stringfield(length=8, start=0)
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version = field(fmt=WORD, start=8)
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xor_key = field(fmt=WORD, start=10)
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root_object_id = field(fmt=DWORD, start=12)
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number_of_objets = field(fmt=QWORD, start=16)
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object_index_offset = field(fmt=QWORD, start=24)
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binding = field(fmt=BYTE, start=36)
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dpi = field(fmt=WORD, start=38)
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width = field(fmt=WORD, start=42)
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height = field(fmt=WORD, start=44)
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color_depth = field(fmt=BYTE, start=46)
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toc_object_id = field(fmt=DWORD, start=0x44)
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toc_object_offset = field(fmt=DWORD, start=0x48)
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compressed_info_size = field(fmt=WORD, start=0x4c)
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thumbnail_type = versioned_field(version, 800, fmt=WORD, start=0x4e)
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thumbnail_size = versioned_field(version, 800, fmt=DWORD, start=0x50)
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uncompressed_info_size = versioned_field(compressed_info_size, 0, \
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version = field(fmt=WORD, start=8)
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xor_key = field(fmt=WORD, start=10)
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root_object_id = field(fmt=DWORD, start=12)
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number_of_objets = field(fmt=QWORD, start=16)
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object_index_offset = field(fmt=QWORD, start=24)
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binding = field(fmt=BYTE, start=36)
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dpi = field(fmt=WORD, start=38)
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width = field(fmt=WORD, start=42)
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height = field(fmt=WORD, start=44)
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color_depth = field(fmt=BYTE, start=46)
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toc_object_id = field(fmt=DWORD, start=0x44)
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toc_object_offset = field(fmt=DWORD, start=0x48)
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compressed_info_size = field(fmt=WORD, start=0x4c)
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thumbnail_type = versioned_field(version, 800, fmt=WORD, start=0x4e)
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thumbnail_size = versioned_field(version, 800, fmt=DWORD, start=0x50)
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uncompressed_info_size = versioned_field(compressed_info_size, 0, \
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fmt=DWORD, start=0x54)
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title = xml_field("Title")
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author = xml_field("Author")
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book_id = xml_field("BookID")
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publisher = xml_field("Publisher")
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label = xml_field("Label")
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category = xml_field("Category")
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title = xml_field("Title", parent="BookInfo")
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author = xml_field("Author", parent="BookInfo")
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book_id = xml_field("BookID", parent="BookInfo")
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publisher = xml_field("Publisher", parent="BookInfo")
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label = xml_field("Label", parent="BookInfo")
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category = xml_field("Category", parent="BookInfo")
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classification = xml_field("Classification", parent="BookInfo")
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free_text = xml_field("FreeText", parent="BookInfo")
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language = xml_field("Language")
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creator = xml_field("Creator")
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creation_date = xml_field("CreationDate") #: Format is %Y-%m-%d
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producer = xml_field("Producer")
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page = xml_field("Page")
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language = xml_field("Language", parent="DocInfo")
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creator = xml_field("Creator", parent="DocInfo")
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# Format is %Y-%m-%d
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creation_date = xml_field("CreationDate", parent="DocInfo")
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producer = xml_field("Producer", parent="DocInfo")
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page = xml_field("Page", parent="DocInfo")
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def safe(func):
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"""
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@ -198,20 +231,36 @@ class LRFMetaFile(object):
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@safe_property
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def info():
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doc = """ Document meta information in raw XML format """
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doc = \
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"""
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Document meta information in raw XML format as a byte string encoded in
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utf-16.
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To set use raw XML in a byte string encoded in utf-16.
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"""
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def fget(self):
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if self.compressed_info_size == 0:
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raise LRFException("This document has no meta info")
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size = self.compressed_info_size - 4
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self._file.seek(self.info_start)
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try:
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stream = zlib.decompress(self._file.read(size))
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if len(stream) != self.uncompressed_info_size:
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src = zlib.decompress(self._file.read(size))
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if len(src) != self.uncompressed_info_size:
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raise LRFException("Decompression of document meta info\
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yielded unexpected results")
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# Remove null characters from string as in some LRF files
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# the stream is null-terminated
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return stream.strip().replace('\0', '')
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yielded unexpected results")
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candidate = unicode(src, 'utf-16')
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# LRF files produced with makelrf dont have a correctly
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# encoded metadata block.
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# Decoding using latin1 is the most useful for me since I
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# occassionally read french books.
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if not u"Info" in candidate:
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candidate = unicode(src, 'latin1', errors='ignore')
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if candidate[-1:] == '\0':
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candidate = candidate[:-1]
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candidate = dom.parseString(candidate.encode('utf-8')).\
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toxml(encoding='utf-16')
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else:
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candidate = candidate.encode('utf-16')
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return candidate.strip()
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except zlib.error, e:
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raise LRFException("Unable to decompress document meta information")
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@ -222,6 +271,7 @@ class LRFMetaFile(object):
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self._file.seek(self.info_start)
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self._file.write(stream)
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self._file.flush()
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return { "fget":fget, "fset":fset, "doc":doc }
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@safe_property
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@ -273,7 +323,7 @@ class LRFMetaFile(object):
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ttype = 0x11
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self.thumbnail_type = ttype
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# Needed as new thumbnail may have different size than old thumbnail
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self.update_object_offsets(self.toc_object_offset - orig_offset)
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self.update_object_offsets(self.toc_object_offset - orig_offset)
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return { "fget":fget, "fset":fset, "doc":doc }
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def __init__(self, file):
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