# -*- coding: utf-8 -*- # # vim: sw=4:expandtab:foldmethod=marker # # Copyright (c) 2006, Mathieu Fenniak # Copyright (c) 2007, Ashish Kulkarni # # All rights reserved. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions are # met: # # * Redistributions of source code must retain the above copyright notice, # this list of conditions and the following disclaimer. # * Redistributions in binary form must reproduce the above copyright notice, # this list of conditions and the following disclaimer in the documentation # and/or other materials provided with the distribution. # * The name of the author may not be used to endorse or promote products # derived from this software without specific prior written permission. # # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE # ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE # LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR # CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF # SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS # INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN # CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE # POSSIBILITY OF SUCH DAMAGE. """ A pure-Python PDF library with an increasing number of capabilities. See README for links to FAQ, documentation, homepage, etc. """ __author__ = "Mathieu Fenniak" __author_email__ = "biziqe@mathieu.fenniak.net" __maintainer__ = "Phaseit, Inc." __maintainer_email = "PyPDF2@phaseit.net" import string import math import struct import sys from sys import version_info if version_info < ( 3, 0 ): from cStringIO import StringIO else: from io import StringIO if version_info < ( 3, 0 ): BytesIO = StringIO else: from io import BytesIO from . import filters from . import utils import warnings import codecs from .generic import * from .utils import readNonWhitespace, readUntilWhitespace, ConvertFunctionsToVirtualList from .utils import Str, b_, u_, ord_, chr_, str_, string_type, formatWarning if version_info < ( 2, 4 ): from sets import ImmutableSet as frozenset if version_info < ( 2, 5 ): from md5 import md5 else: from hashlib import md5 import uuid class PdfFileWriter(object): """ This class supports writing PDF files out, given pages produced by another class (typically :class:`PdfFileReader`). """ def __init__(self): self._header = b_("%PDF-1.3") self._objects = [] # array of indirect objects # The root of our page tree node. pages = DictionaryObject() pages.update({ NameObject("/Type"): NameObject("/Pages"), NameObject("/Count"): NumberObject(0), NameObject("/Kids"): ArrayObject(), }) self._pages = self._addObject(pages) # info object info = DictionaryObject() info.update({ NameObject("/Producer"): createStringObject(codecs.BOM_UTF16_BE + u_("PyPDF2").encode('utf-16be')) }) self._info = self._addObject(info) # root object root = DictionaryObject() root.update({ NameObject("/Type"): NameObject("/Catalog"), NameObject("/Pages"): self._pages, }) self._root = None self._root_object = root def _addObject(self, obj): self._objects.append(obj) return IndirectObject(len(self._objects), 0, self) def getObject(self, ido): if ido.pdf != self: raise ValueError("pdf must be self") return self._objects[ido.idnum - 1] def _addPage(self, page, action): assert page["/Type"] == "/Page" page[NameObject("/Parent")] = self._pages page = self._addObject(page) pages = self.getObject(self._pages) action(pages["/Kids"], page) pages[NameObject("/Count")] = NumberObject(pages["/Count"] + 1) def addPage(self, page): """ Adds a page to this PDF file. The page is usually acquired from a :class:`PdfFileReader` instance. :param PageObject page: The page to add to the document. Should be an instance of :class:`PageObject` """ self._addPage(page, list.append) def insertPage(self, page, index=0): """ Insert a page in this PDF file. The page is usually acquired from a :class:`PdfFileReader` instance. :param PageObject page: The page to add to the document. This argument should be an instance of :class:`PageObject`. :param int index: Position at which the page will be inserted. """ self._addPage(page, lambda l, p: l.insert(index, p)) def getPage(self, pageNumber): """ Retrieves a page by number from this PDF file. :param int pageNumber: The page number to retrieve (pages begin at zero) :return: the page at the index given by *pageNumber* :rtype: :class:`PageObject` """ pages = self.getObject(self._pages) # XXX: crude hack return pages["/Kids"][pageNumber].getObject() def getNumPages(self): """ :return: the number of pages. :rtype: int """ pages = self.getObject(self._pages) return int(pages[NameObject("/Count")]) def addBlankPage(self, width=None, height=None): """ Appends a blank page to this PDF file and returns it. If no page size is specified, use the size of the last page. :param float width: The width of the new page expressed in default user space units. :param float height: The height of the new page expressed in default user space units. :return: the newly appended page :rtype: :class:`PageObject` :raises PageSizeNotDefinedError: if width and height are not defined and previous page does not exist. """ page = PageObject.createBlankPage(self, width, height) self.addPage(page) return page def insertBlankPage(self, width=None, height=None, index=0): """ Inserts a blank page to this PDF file and returns it. If no page size is specified, use the size of the last page. :param float width: The width of the new page expressed in default user space units. :param float height: The height of the new page expressed in default user space units. :param int index: Position to add the page. :return: the newly appended page :rtype: :class:`PageObject` :raises PageSizeNotDefinedError: if width and height are not defined and previous page does not exist. """ if width is None or height is None and \ (self.getNumPages() - 1) >= index: oldpage = self.getPage(index) width = oldpage.mediaBox.getWidth() height = oldpage.mediaBox.getHeight() page = PageObject.createBlankPage(self, width, height) self.insertPage(page, index) return page def addJS(self, javascript): """ Add Javascript which will launch upon opening this PDF. :param str javascript: Your Javascript. >>> output.addJS("this.print({bUI:true,bSilent:false,bShrinkToFit:true});") # Example: This will launch the print window when the PDF is opened. """ js = DictionaryObject() js.update({ NameObject("/Type"): NameObject("/Action"), NameObject("/S"): NameObject("/JavaScript"), NameObject("/JS"): NameObject("(%s)" % javascript) }) self._root_object.update({ NameObject("/OpenAction"): self._addObject(js) }) def encrypt(self, user_pwd, owner_pwd = None, use_128bit = True): """ Encrypt this PDF file with the PDF Standard encryption handler. :param str user_pwd: The "user password", which allows for opening and reading the PDF file with the restrictions provided. :param str owner_pwd: The "owner password", which allows for opening the PDF files without any restrictions. By default, the owner password is the same as the user password. :param bool use_128bit: flag as to whether to use 128bit encryption. When false, 40bit encryption will be used. By default, this flag is on. """ import time, random if owner_pwd == None: owner_pwd = user_pwd if use_128bit: V = 2 rev = 3 keylen = int(128 / 8) else: V = 1 rev = 2 keylen = int(40 / 8) # permit everything: P = -1 O = ByteStringObject(_alg33(owner_pwd, user_pwd, rev, keylen)) ID_1 = ByteStringObject(md5(b_(repr(time.time()))).digest()) ID_2 = ByteStringObject(md5(b_(repr(random.random()))).digest()) self._ID = ArrayObject((ID_1, ID_2)) if rev == 2: U, key = _alg34(user_pwd, O, P, ID_1) else: assert rev == 3 U, key = _alg35(user_pwd, rev, keylen, O, P, ID_1, False) encrypt = DictionaryObject() encrypt[NameObject("/Filter")] = NameObject("/Standard") encrypt[NameObject("/V")] = NumberObject(V) if V == 2: encrypt[NameObject("/Length")] = NumberObject(keylen * 8) encrypt[NameObject("/R")] = NumberObject(rev) encrypt[NameObject("/O")] = ByteStringObject(O) encrypt[NameObject("/U")] = ByteStringObject(U) encrypt[NameObject("/P")] = NumberObject(P) self._encrypt = self._addObject(encrypt) self._encrypt_key = key def write(self, stream): """ Writes the collection of pages added to this object out as a PDF file. :param stream: An object to write the file to. The object must support the write method and the tell method, similar to a file object. """ if hasattr(stream, 'mode') and 'b' not in stream.mode: warnings.warn("File <%s> to write to is not in binary mode. It may not be written to correctly." % stream.name) debug = False import struct if not self._root: self._root = self._addObject(self._root_object) externalReferenceMap = {} # PDF objects sometimes have circular references to their /Page objects # inside their object tree (for example, annotations). Those will be # indirect references to objects that we've recreated in this PDF. To # address this problem, PageObject's store their original object # reference number, and we add it to the external reference map before # we sweep for indirect references. This forces self-page-referencing # trees to reference the correct new object location, rather than # copying in a new copy of the page object. for objIndex in range(len(self._objects)): obj = self._objects[objIndex] if isinstance(obj, PageObject) and obj.indirectRef != None: data = obj.indirectRef if data.pdf not in externalReferenceMap: externalReferenceMap[data.pdf] = {} if data.generation not in externalReferenceMap[data.pdf]: externalReferenceMap[data.pdf][data.generation] = {} externalReferenceMap[data.pdf][data.generation][data.idnum] = IndirectObject(objIndex + 1, 0, self) self.stack = [] if debug: print(("ERM:", externalReferenceMap, "root:", self._root)) self._sweepIndirectReferences(externalReferenceMap, self._root) del self.stack # Begin writing: object_positions = [] stream.write(self._header + b_("\n")) for i in range(len(self._objects)): idnum = (i + 1) obj = self._objects[i] object_positions.append(stream.tell()) stream.write(b_(str(idnum) + " 0 obj\n")) key = None if hasattr(self, "_encrypt") and idnum != self._encrypt.idnum: pack1 = struct.pack("` for details. """ pageRef = self.getObject(self._pages)['/Kids'][pagenum] action = DictionaryObject() zoomArgs = [] for a in args: if a is not None: zoomArgs.append(NumberObject(a)) else: zoomArgs.append(NullObject()) dest = Destination(NameObject("/"+title + " bookmark"), pageRef, NameObject(fit), *zoomArgs) destArray = dest.getDestArray() action.update({ NameObject('/D') : destArray, NameObject('/S') : NameObject('/GoTo') }) actionRef = self._addObject(action) outlineRef = self.getOutlineRoot() if parent == None: parent = outlineRef bookmark = TreeObject() bookmark.update({ NameObject('/A'): actionRef, NameObject('/Title'): createStringObject(title), }) if color is not None: bookmark.update({NameObject('/C'): ArrayObject([FloatObject(c) for c in color])}) format = 0 if italic: format += 1 if bold: format += 2 if format: bookmark.update({NameObject('/F'): NumberObject(format)}) bookmarkRef = self._addObject(bookmark) parent = parent.getObject() parent.addChild(bookmarkRef, self) return bookmarkRef def addNamedDestinationObject(self, dest): destRef = self._addObject(dest) nd = self.getNamedDestRoot() nd.extend([dest['/Title'], destRef]) return destRef def addNamedDestination(self, title, pagenum): pageRef = self.getObject(self._pages)['/Kids'][pagenum] dest = DictionaryObject() dest.update({ NameObject('/D') : ArrayObject([pageRef, NameObject('/FitH'), NumberObject(826)]), NameObject('/S') : NameObject('/GoTo') }) destRef = self._addObject(dest) nd = self.getNamedDestRoot() nd.extend([title, destRef]) return destRef def removeLinks(self): """ Removes links and annotations from this output. """ pages = self.getObject(self._pages)['/Kids'] for page in pages: pageRef = self.getObject(page) if "/Annots" in pageRef: del pageRef['/Annots'] def removeImages(self, ignoreByteStringObject=False): """ Removes images from this output. :param bool ignoreByteStringObject: optional parameter to ignore ByteString Objects. """ pages = self.getObject(self._pages)['/Kids'] for j in range(len(pages)): page = pages[j] pageRef = self.getObject(page) content = pageRef['/Contents'].getObject() if not isinstance(content, ContentStream): content = ContentStream(content, pageRef) _operations = [] seq_graphics = False for operands, operator in content.operations: if operator == b_('Tj'): text = operands[0] if ignoreByteStringObject: if not isinstance(text, TextStringObject): operands[0] = TextStringObject() elif operator == b_("'"): text = operands[0] if ignoreByteStringObject: if not isinstance(text, TextStringObject): operands[0] = TextStringObject() elif operator == b_('"'): text = operands[2] if ignoreByteStringObject: if not isinstance(text, TextStringObject): operands[2] = TextStringObject() elif operator == b_("TJ"): for i in range(len(operands[0])): if ignoreByteStringObject: if not isinstance(operands[0][i], TextStringObject): operands[0][i] = TextStringObject() if operator == b_('q'): seq_graphics = True if operator == b_('Q'): seq_graphics = False if seq_graphics: if operator in [b_('cm'), b_('w'), b_('J'), b_('j'), b_('M'), b_('d'), b_('ri'), b_('i'), b_('gs'), b_('W'), b_('b'), b_('s'), b_('S'), b_('f'), b_('F'), b_('n'), b_('m'), b_('l'), b_('c'), b_('v'), b_('y'), b_('h'), b_('B'), b_('Do'), b_('sh')]: continue if operator == b_('re'): continue _operations.append((operands, operator)) content.operations = _operations pageRef.__setitem__(NameObject('/Contents'), content) def removeText(self, ignoreByteStringObject=False): """ Removes images from this output. :param bool ignoreByteStringObject: optional parameter to ignore ByteString Objects. """ pages = self.getObject(self._pages)['/Kids'] for j in range(len(pages)): page = pages[j] pageRef = self.getObject(page) content = pageRef['/Contents'].getObject() if not isinstance(content, ContentStream): content = ContentStream(content, pageRef) for operands,operator in content.operations: if operator == b_('Tj'): text = operands[0] if not ignoreByteStringObject: if isinstance(text, TextStringObject): operands[0] = TextStringObject() else: if isinstance(text, TextStringObject) or \ isinstance(text, ByteStringObject): operands[0] = TextStringObject() elif operator == b_("'"): text = operands[0] if not ignoreByteStringObject: if isinstance(text, TextStringObject): operands[0] = TextStringObject() else: if isinstance(text, TextStringObject) or \ isinstance(text, ByteStringObject): operands[0] = TextStringObject() elif operator == b_('"'): text = operands[2] if not ignoreByteStringObject: if isinstance(text, TextStringObject): operands[2] = TextStringObject() else: if isinstance(text, TextStringObject) or \ isinstance(text, ByteStringObject): operands[2] = TextStringObject() elif operator == b_("TJ"): for i in range(len(operands[0])): if not ignoreByteStringObject: if isinstance(operands[0][i], TextStringObject): operands[0][i] = TextStringObject() else: if isinstance(operands[0][i], TextStringObject) or \ isinstance(operands[0][i], ByteStringObject): operands[0][i] = TextStringObject() pageRef.__setitem__(NameObject('/Contents'), content) def addLink(self, pagenum, pagedest, rect, border=None, fit='/Fit', *args): """ Add an internal link from a rectangular area to the specified page. :param int pagenum: index of the page on which to place the link. :param int pagedest: index of the page to which the link should go. :param rect: :class:`RectangleObject` or array of four integers specifying the clickable rectangular area ``[xLL, yLL, xUR, yUR]``, or string in the form ``"[ xLL yLL xUR yUR ]"``. :param border: if provided, an array describing border-drawing properties. See the PDF spec for details. No border will be drawn if this argument is omitted. :param str fit: Page fit or 'zoom' option (see below). Additional arguments may need to be supplied. Passing ``None`` will be read as a null value for that coordinate. Valid zoom arguments (see Table 8.2 of the PDF 1.7 reference for details): /Fit No additional arguments /XYZ [left] [top] [zoomFactor] /FitH [top] /FitV [left] /FitR [left] [bottom] [right] [top] /FitB No additional arguments /FitBH [top] /FitBV [left] """ pageLink = self.getObject(self._pages)['/Kids'][pagenum] pageDest = self.getObject(self._pages)['/Kids'][pagedest] #TODO: switch for external link pageRef = self.getObject(pageLink) if border is not None: borderArr = [NameObject(n) for n in border[:3]] if len(border) == 4: dashPattern = ArrayObject([NameObject(n) for n in border[3]]) borderArr.append(dashPattern) else: borderArr = [NumberObject(0)] * 3 if isinstance(rect, Str): rect = NameObject(rect) elif isinstance(rect, RectangleObject): pass else: rect = RectangleObject(rect) zoomArgs = [] for a in args: if a is not None: zoomArgs.append(NumberObject(a)) else: zoomArgs.append(NullObject()) dest = Destination(NameObject("/LinkName"), pageDest, NameObject(fit), *zoomArgs) #TODO: create a better name for the link destArray = dest.getDestArray() lnk = DictionaryObject() lnk.update({ NameObject('/Type'): NameObject('/Annot'), NameObject('/Subtype'): NameObject('/Link'), NameObject('/P'): pageLink, NameObject('/Rect'): rect, NameObject('/Border'): ArrayObject(borderArr), NameObject('/Dest'): destArray }) lnkRef = self._addObject(lnk) if "/Annots" in pageRef: pageRef['/Annots'].append(lnkRef) else: pageRef[NameObject('/Annots')] = ArrayObject([lnkRef]) _valid_layouts = ['/NoLayout', '/SinglePage', '/OneColumn', '/TwoColumnLeft', '/TwoColumnRight', '/TwoPageLeft', '/TwoPageRight'] def getPageLayout(self): """ Get the page layout. See :meth:`setPageLayout()` for a description of valid layouts. :return: Page layout currently being used. :rtype: str, None if not specified """ try: return self._root_object['/PageLayout'] except KeyError: return None def setPageLayout(self, layout): """ Set the page layout :param str layout: The page layout to be used Valid layouts are: /NoLayout Layout explicitly not specified /SinglePage Show one page at a time /OneColumn Show one column at a time /TwoColumnLeft Show pages in two columns, odd-numbered pages on the left /TwoColumnRight Show pages in two columns, odd-numbered pages on the right /TwoPageLeft Show two pages at a time, odd-numbered pages on the left /TwoPageRight Show two pages at a time, odd-numbered pages on the right """ if not isinstance(layout, NameObject): if layout not in self._valid_layouts: warnings.warn("Layout should be one of: {}".format(', '.join(self._valid_layouts))) layout = NameObject(layout) self._root_object.update({NameObject('/PageLayout'): layout}) pageLayout = property(getPageLayout, setPageLayout) """Read and write property accessing the :meth:`getPageLayout()` and :meth:`setPageLayout()` methods.""" _valid_modes = ['/UseNone', '/UseOutlines', '/UseThumbs', '/FullScreen', '/UseOC', '/UseAttachments'] def getPageMode(self): """ Get the page mode. See :meth:`setPageMode()` for a description of valid modes. :return: Page mode currently being used. :rtype: str, None if not specified """ try: return self._root_object['/PageMode'] except KeyError: return None def setPageMode(self, mode): """ Set the page mode. :param str mode: The page mode to use. Valid modes are: /UseNone Do not show outlines or thumbnails panels /UseOutlines Show outlines (aka bookmarks) panel /UseThumbs Show page thumbnails panel /FullScreen Fullscreen view /UseOC Show Optional Content Group (OCG) panel /UseAttachments Show attachments panel """ if not isinstance(mode, NameObject): if mode not in self._valid_modes: warnings.warn("Mode should be one of: {}".format(', '.join(self._valid_modes))) mode = NameObject(mode) self._root_object.update({NameObject('/PageMode'): mode}) pageMode = property(getPageMode, setPageMode) """Read and write property accessing the :meth:`getPageMode()` and :meth:`setPageMode()` methods.""" class PdfFileReader(object): """ Initializes a PdfFileReader object. This operation can take some time, as the PDF stream's cross-reference tables are read into memory. :param stream: A File object or an object that supports the standard read and seek methods similar to a File object. Could also be a string representing a path to a PDF file. :param bool strict: Determines whether user should be warned of all problems and also causes some correctable problems to be fatal. Defaults to ``True``. :param warndest: Destination for logging warnings (defaults to ``sys.stderr``). :param bool overwriteWarnings: Determines whether to override Python's ``warnings.py`` module with a custom implementation (defaults to ``True``). """ def __init__(self, stream, strict=True, warndest = None, overwriteWarnings = True): if overwriteWarnings: # have to dynamically override the default showwarning since there are no # public methods that specify the 'file' parameter def _showwarning(message, category, filename, lineno, file=warndest, line=None): if file is None: file = sys.stderr try: file.write(formatWarning(message, category, filename, lineno, line)) except IOError: pass warnings.showwarning = _showwarning self.strict = strict self.flattenedPages = None self.resolvedObjects = {} self.xrefIndex = 0 if hasattr(stream, 'mode') and 'b' not in stream.mode: warnings.warn("PdfFileReader stream/file object is not in binary mode. It may not be read correctly.", utils.PdfReadWarning) if type(stream) in (string_type, str): fileobj = open(stream, 'rb') stream = BytesIO(b_(fileobj.read())) fileobj.close() self.read(stream) self.stream = stream self._override_encryption = False def getDocumentInfo(self): """ Retrieves the PDF file's document information dictionary, if it exists. Note that some PDF files use metadata streams instead of docinfo dictionaries, and these metadata streams will not be accessed by this function. :return: the document information of this PDF file :rtype: :class:`DocumentInformation` or ``None`` if none exists. """ if "/Info" not in self.trailer: return None obj = self.trailer['/Info'] retval = DocumentInformation() retval.update(obj) return retval documentInfo = property(lambda self: self.getDocumentInfo(), None, None) """Read-only property that accesses the :meth:`getDocumentInfo()` function.""" def getXmpMetadata(self): """ Retrieves XMP (Extensible Metadata Platform) data from the PDF document root. :return: a :class:`XmpInformation` instance that can be used to access XMP metadata from the document. :rtype: :class:`XmpInformation` or ``None`` if no metadata was found on the document root. """ try: self._override_encryption = True return self.trailer["/Root"].getXmpMetadata() finally: self._override_encryption = False xmpMetadata = property(lambda self: self.getXmpMetadata(), None, None) """ Read-only property that accesses the :meth:`getXmpMetadata()` function. """ def getNumPages(self): """ Calculates the number of pages in this PDF file. :return: number of pages :rtype: int :raises PdfReadError: if file is encrypted and restrictions prevent this action. """ # Flattened pages will not work on an Encrypted PDF; # the PDF file's page count is used in this case. Otherwise, # the original method (flattened page count) is used. if self.isEncrypted: try: self._override_encryption = True return self.trailer["/Root"]["/Pages"]["/Count"] except: raise utils.PdfReadError("File has not been decrypted") finally: self._override_encryption = False else: if self.flattenedPages == None: self._flatten() return len(self.flattenedPages) numPages = property(lambda self: self.getNumPages(), None, None) """ Read-only property that accesses the :meth:`getNumPages()` function. """ def getPage(self, pageNumber): """ Retrieves a page by number from this PDF file. :param int pageNumber: The page number to retrieve (pages begin at zero) :return: a :class:`PageObject` instance. :rtype: :class:`PageObject` """ ## ensure that we're not trying to access an encrypted PDF #assert not self.trailer.has_key("/Encrypt") if self.flattenedPages == None: self._flatten() return self.flattenedPages[pageNumber] namedDestinations = property(lambda self: self.getNamedDestinations(), None, None) """ Read-only property that accesses the :meth:`getNamedDestinations()` function. """ # A select group of relevant field attributes. For the complete list, # see section 8.6.2 of the PDF 1.7 reference. def getFields(self, tree = None, retval = None, fileobj = None): """ Extracts field data if this PDF contains interactive form fields. The *tree* and *retval* parameters are for recursive use. :param fileobj: A file object (usually a text file) to write a report to on all interactive form fields found. :return: A dictionary where each key is a field name, and each value is a :class:`Field` object. By default, the mapping name is used for keys. :rtype: dict, or ``None`` if form data could not be located. """ fieldAttributes = {"/FT" : "Field Type", "/Parent" : "Parent", "/T" : "Field Name", "/TU" : "Alternate Field Name", "/TM" : "Mapping Name", "/Ff" : "Field Flags", "/V" : "Value", "/DV" : "Default Value"} if retval == None: retval = {} catalog = self.trailer["/Root"] # get the AcroForm tree if "/AcroForm" in catalog: tree = catalog["/AcroForm"] else: return None if tree == None: return retval self._checkKids(tree, retval, fileobj) for attr in fieldAttributes: if attr in tree: # Tree is a field self._buildField(tree, retval, fileobj, fieldAttributes) break if "/Fields" in tree: fields = tree["/Fields"] for f in fields: field = f.getObject() self._buildField(field, retval, fileobj, fieldAttributes) return retval def _buildField(self, field, retval, fileobj, fieldAttributes): self._checkKids(field, retval, fileobj) try: key = field["/TM"] except KeyError: try: key = field["/T"] except KeyError: # Ignore no-name field for now return if fileobj: self._writeField(fileobj, field, fieldAttributes) fileobj.write("\n") retval[key] = Field(field) def _checkKids(self, tree, retval, fileobj): if "/Kids" in tree: # recurse down the tree for kid in tree["/Kids"]: self.getFields(kid.getObject(), retval, fileobj) def _writeField(self, fileobj, field, fieldAttributes): order = ["/TM", "/T", "/FT", "/Parent", "/TU", "/Ff", "/V", "/DV"] for attr in order: attrName = fieldAttributes[attr] try: if attr == "/FT": # Make the field type value more clear types = {"/Btn":"Button", "/Tx":"Text", "/Ch": "Choice", "/Sig":"Signature"} if field[attr] in types: fileobj.write(attrName + ": " + types[field[attr]] + "\n") elif attr == "/Parent": # Let's just write the name of the parent try: name = field["/Parent"]["/TM"] except KeyError: name = field["/Parent"]["/T"] fileobj.write(attrName + ": " + name + "\n") else: fileobj.write(attrName + ": " + str(field[attr]) + "\n") except KeyError: # Field attribute is N/A or unknown, so don't write anything pass def getNamedDestinations(self, tree=None, retval=None): """ Retrieves the named destinations present in the document. :return: a dictionary which maps names to :class:`Destinations`. :rtype: dict """ if retval == None: retval = {} catalog = self.trailer["/Root"] # get the name tree if "/Dests" in catalog: tree = catalog["/Dests"] elif "/Names" in catalog: names = catalog['/Names'] if "/Dests" in names: tree = names['/Dests'] if tree == None: return retval if "/Kids" in tree: # recurse down the tree for kid in tree["/Kids"]: self.getNamedDestinations(kid.getObject(), retval) if "/Names" in tree: names = tree["/Names"] for i in range(0, len(names), 2): key = names[i].getObject() val = names[i+1].getObject() if isinstance(val, DictionaryObject) and '/D' in val: val = val['/D'] dest = self._buildDestination(key, val) if dest != None: retval[key] = dest return retval outlines = property(lambda self: self.getOutlines(), None, None) """ Read-only property that accesses the :meth:`getOutlines()` function. """ def getOutlines(self, node=None, outlines=None): """ Retrieves the document outline present in the document. :return: a nested list of :class:`Destinations`. """ if outlines == None: outlines = [] catalog = self.trailer["/Root"] # get the outline dictionary and named destinations if "/Outlines" in catalog: lines = catalog["/Outlines"] if "/First" in lines: node = lines["/First"] self._namedDests = self.getNamedDestinations() if node == None: return outlines # see if there are any more outlines while True: outline = self._buildOutline(node) if outline: outlines.append(outline) # check for sub-outlines if "/First" in node: subOutlines = [] self.getOutlines(node["/First"], subOutlines) if subOutlines: outlines.append(subOutlines) if "/Next" not in node: break node = node["/Next"] return outlines def _buildDestination(self, title, array): page, typ = array[0:2] array = array[2:] return Destination(title, page, typ, *array) def _buildOutline(self, node): dest, title, outline = None, None, None if "/A" in node and "/Title" in node: # Action, section 8.5 (only type GoTo supported) title = node["/Title"] action = node["/A"] if action["/S"] == "/GoTo": dest = action["/D"] elif "/Dest" in node and "/Title" in node: # Destination, section 8.2.1 title = node["/Title"] dest = node["/Dest"] # if destination found, then create outline if dest: if isinstance(dest, ArrayObject): outline = self._buildDestination(title, dest) elif isinstance(dest, Str) and dest in self._namedDests: outline = self._namedDests[dest] outline[NameObject("/Title")] = title else: raise utils.PdfReadError("Unexpected destination %r" % dest) return outline pages = property(lambda self: ConvertFunctionsToVirtualList(self.getNumPages, self.getPage), None, None) """ Read-only property that emulates a list based upon the :meth:`getNumPages()` and :meth:`getPage()` methods. """ def getPageLayout(self): """ Get the page layout. See :meth:`setPageLayout()` for a description of valid layouts. :return: Page layout currently being used. :rtype: ``str``, ``None`` if not specified """ try: return self.trailer['/Root']['/PageLayout'] except KeyError: return None pageLayout = property(getPageLayout) """Read-only property accessing the :meth:`getPageLayout()` method.""" def getPageMode(self): """ Get the page mode. See :meth:`setPageMode()` for a description of valid modes. :return: Page mode currently being used. :rtype: ``str``, ``None`` if not specified """ try: return self.trailer['/Root']['/PageMode'] except KeyError: return None pageMode = property(getPageMode) """Read-only property accessing the :meth:`getPageMode()` method.""" def _flatten(self, pages=None, inherit=None, indirectRef=None): inheritablePageAttributes = ( NameObject("/Resources"), NameObject("/MediaBox"), NameObject("/CropBox"), NameObject("/Rotate") ) if inherit == None: inherit = dict() if pages == None: self.flattenedPages = [] catalog = self.trailer["/Root"].getObject() pages = catalog["/Pages"].getObject() t = "/Pages" if "/Type" in pages: t = pages["/Type"] if t == "/Pages": for attr in inheritablePageAttributes: if attr in pages: inherit[attr] = pages[attr] for page in pages["/Kids"]: addt = {} if isinstance(page, IndirectObject): addt["indirectRef"] = page self._flatten(page.getObject(), inherit, **addt) elif t == "/Page": for attr, value in list(inherit.items()): # if the page has it's own value, it does not inherit the # parent's value: if attr not in pages: pages[attr] = value pageObj = PageObject(self, indirectRef) pageObj.update(pages) self.flattenedPages.append(pageObj) def _getObjectFromStream(self, indirectReference): # indirect reference to object in object stream # read the entire object stream into memory debug = False stmnum, idx = self.xref_objStm[indirectReference.idnum] if debug: print(("Here1: %s %s"%(stmnum, idx))) objStm = IndirectObject(stmnum, 0, self).getObject() if debug: print(("Here2: objStm=%s.. stmnum=%s data=%s"%(objStm, stmnum, objStm.getData()))) # This is an xref to a stream, so its type better be a stream assert objStm['/Type'] == '/ObjStm' # /N is the number of indirect objects in the stream assert idx < objStm['/N'] streamData = BytesIO(b_(objStm.getData())) for i in range(objStm['/N']): objnum = NumberObject.readFromStream(streamData) readNonWhitespace(streamData) streamData.seek(-1, 1) offset = NumberObject.readFromStream(streamData) readNonWhitespace(streamData) streamData.seek(-1, 1) if objnum != indirectReference.idnum: # We're only interested in one object continue if self.strict and idx != i: raise utils.PdfReadError("Object is in wrong index.") streamData.seek(objStm['/First']+offset, 0) if debug: pos = streamData.tell() streamData.seek(0, 0) lines = streamData.readlines() for i in range(0, len(lines)): print((lines[i])) streamData.seek(pos, 0) try: obj = readObject(streamData, self) except utils.PdfStreamError as e: # Stream object cannot be read. Normally, a critical error, but # Adobe Reader doesn't complain, so continue (in strict mode?) e = sys.exc_info()[1] warnings.warn("Invalid stream (index %d) within object %d %d: %s" % \ (i, indirectReference.idnum, indirectReference.generation, e), utils.PdfReadWarning) if self.strict: raise utils.PdfReadError("Can't read object stream: %s"%e) # Replace with null. Hopefully it's nothing important. obj = NullObject() return obj if self.strict: raise utils.PdfReadError("This is a fatal error in strict mode.") return NullObject() def getObject(self, indirectReference): debug = False if debug: print(("looking at:", indirectReference.idnum, indirectReference.generation)) retval = self.cacheGetIndirectObject(indirectReference.generation, indirectReference.idnum) if retval != None: return retval if indirectReference.generation == 0 and \ indirectReference.idnum in self.xref_objStm: retval = self._getObjectFromStream(indirectReference) elif indirectReference.generation in self.xref and \ indirectReference.idnum in self.xref[indirectReference.generation]: start = self.xref[indirectReference.generation][indirectReference.idnum] if debug: print((" Uncompressed Object", indirectReference.idnum, indirectReference.generation, ":", start)) self.stream.seek(start, 0) idnum, generation = self.readObjectHeader(self.stream) if idnum != indirectReference.idnum and self.xrefIndex: # Xref table probably had bad indexes due to not being zero-indexed if self.strict: raise utils.PdfReadError("Expected object ID (%d %d) does not match actual (%d %d); xref table not zero-indexed." \ % (indirectReference.idnum, indirectReference.generation, idnum, generation)) else: pass # xref table is corrected in non-strict mode elif idnum != indirectReference.idnum: # some other problem raise utils.PdfReadError("Expected object ID (%d %d) does not match actual (%d %d)." \ % (indirectReference.idnum, indirectReference.generation, idnum, generation)) assert generation == indirectReference.generation retval = readObject(self.stream, self) # override encryption is used for the /Encrypt dictionary if not self._override_encryption and self.isEncrypted: # if we don't have the encryption key: if not hasattr(self, '_decryption_key'): raise utils.PdfReadError("file has not been decrypted") # otherwise, decrypt here... import struct pack1 = struct.pack(">read", stream) # start at the end: stream.seek(-1, 2) if not stream.tell(): raise utils.PdfReadError('Cannot read an empty file') last1K = stream.tell() - 1024 + 1 # offset of last 1024 bytes of stream line = b_('') while line[:5] != b_("%%EOF"): if stream.tell() < last1K: raise utils.PdfReadError("EOF marker not found") line = self.readNextEndLine(stream) if debug: print(" line:",line) # find startxref entry - the location of the xref table line = self.readNextEndLine(stream) try: startxref = int(line) except ValueError: # 'startxref' may be on the same line as the location if not line.startswith("startxref"): raise utils.PdfReadError("startxref not found") startxref = int(line[9:].strip()) warnings.warn("startxref on same line as offset") else: line = self.readNextEndLine(stream) if line[:9] != b_("startxref"): raise utils.PdfReadError("startxref not found") # read all cross reference tables and their trailers self.xref = {} self.xref_objStm = {} self.trailer = DictionaryObject() while True: # load the xref table stream.seek(startxref, 0) x = stream.read(1) if x == b_("x"): # standard cross-reference table ref = stream.read(4) if ref[:3] != b_("ref"): raise utils.PdfReadError("xref table read error") readNonWhitespace(stream) stream.seek(-1, 1) firsttime = True; # check if the first time looking at the xref table while True: num = readObject(stream, self) if firsttime and num != 0: self.xrefIndex = num warnings.warn("Xref table not zero-indexed. ID numbers for objects will %sbe corrected." % \ ("" if not self.strict else "not "), utils.PdfReadWarning) #if table not zero indexed, could be due to error from when PDF was created #which will lead to mismatched indices later on firsttime = False readNonWhitespace(stream) stream.seek(-1, 1) size = readObject(stream, self) readNonWhitespace(stream) stream.seek(-1, 1) cnt = 0 while cnt < size: line = stream.read(20) # It's very clear in section 3.4.3 of the PDF spec # that all cross-reference table lines are a fixed # 20 bytes (as of PDF 1.7). However, some files have # 21-byte entries (or more) due to the use of \r\n # (CRLF) EOL's. Detect that case, and adjust the line # until it does not begin with a \r (CR) or \n (LF). while line[0] in b_("\x0D\x0A"): stream.seek(-20 + 1, 1) line = stream.read(20) # On the other hand, some malformed PDF files # use a single character EOL without a preceeding # space. Detect that case, and seek the stream # back one character. (0-9 means we've bled into # the next xref entry, t means we've bled into the # text "trailer"): if line[-1] in b_("0123456789t"): stream.seek(-1, 1) offset, generation = line[:16].split(b_(" ")) offset, generation = int(offset), int(generation) if generation not in self.xref: self.xref[generation] = {} if num in self.xref[generation]: # It really seems like we should allow the last # xref table in the file to override previous # ones. Since we read the file backwards, assume # any existing key is already set correctly. pass else: self.xref[generation][num] = offset cnt += 1 num += 1 readNonWhitespace(stream) stream.seek(-1, 1) trailertag = stream.read(7) if trailertag != b_("trailer"): # more xrefs! stream.seek(-7, 1) else: break readNonWhitespace(stream) stream.seek(-1, 1) newTrailer = readObject(stream, self) for key, value in list(newTrailer.items()): if key not in self.trailer: self.trailer[key] = value if "/Prev" in newTrailer: startxref = newTrailer["/Prev"] else: break elif x.isdigit(): # PDF 1.5+ Cross-Reference Stream stream.seek(-1, 1) idnum, generation = self.readObjectHeader(stream) xrefstream = readObject(stream, self) assert xrefstream["/Type"] == "/XRef" self.cacheIndirectObject(generation, idnum, xrefstream) streamData = BytesIO(b_(xrefstream.getData())) # Index pairs specify the subsections in the dictionary. If # none create one subsection that spans everything. idx_pairs = xrefstream.get("/Index", [0, xrefstream.get("/Size")]) if debug: print(("read idx_pairs=%s"%list(self._pairs(idx_pairs)))) entrySizes = xrefstream.get("/W") assert len(entrySizes) >= 3 if self.strict and len(entrySizes) > 3: raise utils.PdfReadError("Too many entry sizes: %s" %entrySizes) def getEntry(i): # Reads the correct number of bytes for each entry. See the # discussion of the W parameter in PDF spec table 17. if entrySizes[i] > 0: d = streamData.read(entrySizes[i]) return convertToInt(d, entrySizes[i]) # PDF Spec Table 17: A value of zero for an element in the # W array indicates...the default value shall be used if i == 0: return 1 # First value defaults to 1 else: return 0 def used_before(num, generation): # We move backwards through the xrefs, don't replace any. return num in self.xref.get(generation, []) or \ num in self.xref_objStm # Iterate through each subsection last_end = 0 for start, size in self._pairs(idx_pairs): # The subsections must increase assert start >= last_end last_end = start + size for num in range(start, start+size): # The first entry is the type xref_type = getEntry(0) # The rest of the elements depend on the xref_type if xref_type == 0: # linked list of free objects next_free_object = getEntry(1) next_generation = getEntry(2) elif xref_type == 1: # objects that are in use but are not compressed byte_offset = getEntry(1) generation = getEntry(2) if generation not in self.xref: self.xref[generation] = {} if not used_before(num, generation): self.xref[generation][num] = byte_offset if debug: print(("XREF Uncompressed: %s %s"%( num, generation))) elif xref_type == 2: # compressed objects objstr_num = getEntry(1) obstr_idx = getEntry(2) generation = 0 # PDF spec table 18, generation is 0 if not used_before(num, generation): if debug: print(("XREF Compressed: %s %s %s"%( num, objstr_num, obstr_idx))) self.xref_objStm[num] = (objstr_num, obstr_idx) elif self.strict: raise utils.PdfReadError("Unknown xref type: %s"% xref_type) trailerKeys = "/Root", "/Encrypt", "/Info", "/ID" for key in trailerKeys: if key in xrefstream and key not in self.trailer: self.trailer[NameObject(key)] = xrefstream.raw_get(key) if "/Prev" in xrefstream: startxref = xrefstream["/Prev"] else: break else: # bad xref character at startxref. Let's see if we can find # the xref table nearby, as we've observed this error with an # off-by-one before. stream.seek(-11, 1) tmp = stream.read(20) xref_loc = tmp.find(b_("xref")) if xref_loc != -1: startxref -= (10 - xref_loc) continue # No explicit xref table, try finding a cross-reference stream. stream.seek(startxref, 0) found = False for look in range(5): if stream.read(1).isdigit(): # This is not a standard PDF, consider adding a warning startxref += look found = True break if found: continue # no xref table found at specified location assert False break #if not zero-indexed, verify that the table is correct; change it if necessary if self.xrefIndex and not self.strict: loc = stream.tell() for gen in self.xref: if gen == 65535: continue for id in self.xref[gen]: stream.seek(self.xref[gen][id], 0) try: pid, pgen = self.readObjectHeader(stream) except ValueError: break if pid == id - self.xrefIndex: self._zeroXref(gen) break #if not, then either it's just plain wrong, or the non-zero-index is actually correct stream.seek(loc, 0) #return to where it was def _zeroXref(self, generation): self.xref[generation] = dict( (k-self.xrefIndex, v) for (k, v) in list(self.xref[generation].items()) ) def _pairs(self, array): i = 0 while True: yield array[i], array[i+1] i += 2 if (i+1) >= len(array): break def readNextEndLine(self, stream): debug = False if debug: print(">>readNextEndLine") line = b_("") while True: x = stream.read(1) if debug: print((" x:", x, "%x"%ord(x))) stream.seek(-2, 1) if x == b_('\n') or x == b_('\r'): ## \n = LF; \r = CR crlf = False while x == b_('\n') or x == b_('\r'): if debug: if ord(x) == 0x0D: print(" x is CR 0D") elif ord(x) == 0x0A: print(" x is LF 0A") x = stream.read(1) if x == b_('\n') or x == b_('\r'): # account for CR+LF stream.seek(-1, 1) crlf = True stream.seek(-2, 1) stream.seek(2 if crlf else 1, 1) #if using CR+LF, go back 2 bytes, else 1 break else: if debug: print(" x is neither") line = x + line if debug: print((" RNEL line:", line)) if debug: print("leaving RNEL") return line def decrypt(self, password): """ When using an encrypted / secured PDF file with the PDF Standard encryption handler, this function will allow the file to be decrypted. It checks the given password against the document's user password and owner password, and then stores the resulting decryption key if either password is correct. It does not matter which password was matched. Both passwords provide the correct decryption key that will allow the document to be used with this library. :param str password: The password to match. :return: ``0`` if the password failed, ``1`` if the password matched the user password, and ``2`` if the password matched the owner password. :rtype: int :raises NotImplementedError: if document uses an unsupported encryption method. """ self._override_encryption = True try: return self._decrypt(password) finally: self._override_encryption = False def _decrypt(self, password): encrypt = self.trailer['/Encrypt'].getObject() if encrypt['/Filter'] != '/Standard': raise NotImplementedError("only Standard PDF encryption handler is available") if not (encrypt['/V'] in (1, 2)): raise NotImplementedError("only algorithm code 1 and 2 are supported") user_password, key = self._authenticateUserPassword(password) if user_password: self._decryption_key = key return 1 else: rev = encrypt['/R'].getObject() if rev == 2: keylen = 5 else: keylen = encrypt['/Length'].getObject() // 8 key = _alg33_1(password, rev, keylen) real_O = encrypt["/O"].getObject() if rev == 2: userpass = utils.RC4_encrypt(key, real_O) else: val = real_O for i in range(19, -1, -1): new_key = b_('') for l in range(len(key)): new_key += b_(chr(utils.ord_(key[l]) ^ i)) val = utils.RC4_encrypt(new_key, val) userpass = val owner_password, key = self._authenticateUserPassword(userpass) if owner_password: self._decryption_key = key return 2 return 0 def _authenticateUserPassword(self, password): encrypt = self.trailer['/Encrypt'].getObject() rev = encrypt['/R'].getObject() owner_entry = encrypt['/O'].getObject() p_entry = encrypt['/P'].getObject() id_entry = self.trailer['/ID'].getObject() id1_entry = id_entry[0].getObject() real_U = encrypt['/U'].getObject().original_bytes if rev == 2: U, key = _alg34(password, owner_entry, p_entry, id1_entry) elif rev >= 3: U, key = _alg35(password, rev, encrypt["/Length"].getObject() // 8, owner_entry, p_entry, id1_entry, encrypt.get("/EncryptMetadata", BooleanObject(False)).getObject()) U, real_U = U[:16], real_U[:16] return U == real_U, key def getIsEncrypted(self): return "/Encrypt" in self.trailer isEncrypted = property(lambda self: self.getIsEncrypted(), None, None) """ Read-only boolean property showing whether this PDF file is encrypted. Note that this property, if true, will remain true even after the :meth:`decrypt()` method is called. """ def getRectangle(self, name, defaults): retval = self.get(name) if isinstance(retval, RectangleObject): return retval if retval == None: for d in defaults: retval = self.get(d) if retval != None: break if isinstance(retval, IndirectObject): retval = self.pdf.getObject(retval) retval = RectangleObject(retval) setRectangle(self, name, retval) return retval def setRectangle(self, name, value): if not isinstance(name, NameObject): name = NameObject(name) self[name] = value def deleteRectangle(self, name): del self[name] def createRectangleAccessor(name, fallback): return \ property( lambda self: getRectangle(self, name, fallback), lambda self, value: setRectangle(self, name, value), lambda self: deleteRectangle(self, name) ) class PageObject(DictionaryObject): """ This class represents a single page within a PDF file. Typically this object will be created by accessing the :meth:`getPage()` method of the :class:`PdfFileReader` class, but it is also possible to create an empty page with the :meth:`createBlankPage()` static method. :param pdf: PDF file the page belongs to. :param indirectRef: Stores the original indirect reference to this object in its source PDF """ def __init__(self, pdf=None, indirectRef=None): DictionaryObject.__init__(self) self.pdf = pdf self.indirectRef = indirectRef def createBlankPage(pdf=None, width=None, height=None): """ Returns a new blank page. If ``width`` or ``height`` is ``None``, try to get the page size from the last page of *pdf*. :param pdf: PDF file the page belongs to :param float width: The width of the new page expressed in default user space units. :param float height: The height of the new page expressed in default user space units. :return: the new blank page: :rtype: :class:`PageObject` :raises PageSizeNotDefinedError: if ``pdf`` is ``None`` or contains no page """ page = PageObject(pdf) # Creates a new page (cf PDF Reference 7.7.3.3) page.__setitem__(NameObject('/Type'), NameObject('/Page')) page.__setitem__(NameObject('/Parent'), NullObject()) page.__setitem__(NameObject('/Resources'), DictionaryObject()) if width is None or height is None: if pdf is not None and pdf.getNumPages() > 0: lastpage = pdf.getPage(pdf.getNumPages() - 1) width = lastpage.mediaBox.getWidth() height = lastpage.mediaBox.getHeight() else: raise utils.PageSizeNotDefinedError() page.__setitem__(NameObject('/MediaBox'), RectangleObject([0, 0, width, height])) return page createBlankPage = staticmethod(createBlankPage) def rotateClockwise(self, angle): """ Rotates a page clockwise by increments of 90 degrees. :param int angle: Angle to rotate the page. Must be an increment of 90 deg. """ assert angle % 90 == 0 self._rotate(angle) return self def rotateCounterClockwise(self, angle): """ Rotates a page counter-clockwise by increments of 90 degrees. :param int angle: Angle to rotate the page. Must be an increment of 90 deg. """ assert angle % 90 == 0 self._rotate(-angle) return self def _rotate(self, angle): currentAngle = self.get("/Rotate", 0) self[NameObject("/Rotate")] = NumberObject(currentAngle + angle) def _mergeResources(res1, res2, resource): newRes = DictionaryObject() newRes.update(res1.get(resource, DictionaryObject()).getObject()) page2Res = res2.get(resource, DictionaryObject()).getObject() renameRes = {} for key in list(page2Res.keys()): if key in newRes and newRes[key] != page2Res[key]: newname = NameObject(key + str(uuid.uuid4())) renameRes[key] = newname newRes[newname] = page2Res[key] elif key not in newRes: newRes[key] = page2Res.raw_get(key) return newRes, renameRes _mergeResources = staticmethod(_mergeResources) def _contentStreamRename(stream, rename, pdf): if not rename: return stream stream = ContentStream(stream, pdf) for operands, operator in stream.operations: for i in range(len(operands)): op = operands[i] if isinstance(op, NameObject): operands[i] = rename.get(op,op) return stream _contentStreamRename = staticmethod(_contentStreamRename) def _pushPopGS(contents, pdf): # adds a graphics state "push" and "pop" to the beginning and end # of a content stream. This isolates it from changes such as # transformation matricies. stream = ContentStream(contents, pdf) stream.operations.insert(0, [[], "q"]) stream.operations.append([[], "Q"]) return stream _pushPopGS = staticmethod(_pushPopGS) def _addTransformationMatrix(contents, pdf, ctm): # adds transformation matrix at the beginning of the given # contents stream. a, b, c, d, e, f = ctm contents = ContentStream(contents, pdf) contents.operations.insert(0, [[FloatObject(a), FloatObject(b), FloatObject(c), FloatObject(d), FloatObject(e), FloatObject(f)], " cm"]) return contents _addTransformationMatrix = staticmethod(_addTransformationMatrix) def getContents(self): """ Accesses the page contents. :return: the ``/Contents`` object, or ``None`` if it doesn't exist. ``/Contents`` is optional, as described in PDF Reference 7.7.3.3 """ if "/Contents" in self: return self["/Contents"].getObject() else: return None def mergePage(self, page2): """ Merges the content streams of two pages into one. Resource references (i.e. fonts) are maintained from both pages. The mediabox/cropbox/etc of this page are not altered. The parameter page's content stream will be added to the end of this page's content stream, meaning that it will be drawn after, or "on top" of this page. :param PageObject page2: The page to be merged into this one. Should be an instance of :class:`PageObject`. """ self._mergePage(page2) def _mergePage(self, page2, page2transformation=None, ctm=None, expand=False): # First we work on merging the resource dictionaries. This allows us # to find out what symbols in the content streams we might need to # rename. newResources = DictionaryObject() rename = {} originalResources = self["/Resources"].getObject() page2Resources = page2["/Resources"].getObject() newAnnots = ArrayObject() for page in (self, page2): if "/Annots" in page: annots = page["/Annots"] if isinstance(annots, ArrayObject): for ref in annots: newAnnots.append(ref) for res in "/ExtGState", "/Font", "/XObject", "/ColorSpace", "/Pattern", "/Shading", "/Properties": new, newrename = PageObject._mergeResources(originalResources, page2Resources, res) if new: newResources[NameObject(res)] = new rename.update(newrename) # Combine /ProcSet sets. newResources[NameObject("/ProcSet")] = ArrayObject( frozenset(originalResources.get("/ProcSet", ArrayObject()).getObject()).union( frozenset(page2Resources.get("/ProcSet", ArrayObject()).getObject()) ) ) newContentArray = ArrayObject() originalContent = self.getContents() if originalContent is not None: newContentArray.append(PageObject._pushPopGS( originalContent, self.pdf)) page2Content = page2.getContents() if page2Content is not None: if page2transformation is not None: page2Content = page2transformation(page2Content) page2Content = PageObject._contentStreamRename( page2Content, rename, self.pdf) page2Content = PageObject._pushPopGS(page2Content, self.pdf) newContentArray.append(page2Content) # if expanding the page to fit a new page, calculate the new media box size if expand: corners1 = [self.mediaBox.getLowerLeft_x().as_numeric(), self.mediaBox.getLowerLeft_y().as_numeric(), self.mediaBox.getUpperRight_x().as_numeric(), self.mediaBox.getUpperRight_y().as_numeric()] corners2 = [page2.mediaBox.getLowerLeft_x().as_numeric(), page2.mediaBox.getLowerLeft_y().as_numeric(), page2.mediaBox.getUpperLeft_x().as_numeric(), page2.mediaBox.getUpperLeft_y().as_numeric(), page2.mediaBox.getUpperRight_x().as_numeric(), page2.mediaBox.getUpperRight_y().as_numeric(), page2.mediaBox.getLowerRight_x().as_numeric(), page2.mediaBox.getLowerRight_y().as_numeric()] if ctm is not None: ctm = [float(x) for x in ctm] new_x = [ctm[0]*corners2[i] + ctm[2]*corners2[i+1] + ctm[4] for i in range(0, 8, 2)] new_y = [ctm[1]*corners2[i] + ctm[3]*corners2[i+1] + ctm[5] for i in range(0, 8, 2)] else: new_x = corners2[0:8:2] new_y = corners2[1:8:2] lowerleft = [min(new_x), min(new_y)] upperright = [max(new_x), max(new_y)] lowerleft = [min(corners1[0], lowerleft[0]), min(corners1[1], lowerleft[1])] upperright = [max(corners1[2], upperright[0]), max(corners1[3], upperright[1])] self.mediaBox.setLowerLeft(lowerleft) self.mediaBox.setUpperRight(upperright) self[NameObject('/Contents')] = ContentStream(newContentArray, self.pdf) self[NameObject('/Resources')] = newResources self[NameObject('/Annots')] = newAnnots def mergeTransformedPage(self, page2, ctm, expand=False): """ This is similar to mergePage, but a transformation matrix is applied to the merged stream. :param PageObject page2: The page to be merged into this one. Should be an instance of :class:`PageObject`. :param tuple ctm: a 6-element tuple containing the operands of the transformation matrix :param bool expand: Whether the page should be expanded to fit the dimensions of the page to be merged. """ self._mergePage(page2, lambda page2Content: PageObject._addTransformationMatrix(page2Content, page2.pdf, ctm), ctm, expand) def mergeScaledPage(self, page2, scale, expand=False): """ This is similar to mergePage, but the stream to be merged is scaled by appling a transformation matrix. :param PageObject page2: The page to be merged into this one. Should be an instance of :class:`PageObject`. :param float scale: The scaling factor :param bool expand: Whether the page should be expanded to fit the dimensions of the page to be merged. """ # CTM to scale : [ sx 0 0 sy 0 0 ] return self.mergeTransformedPage(page2, [scale, 0, 0, scale, 0, 0], expand) def mergeRotatedPage(self, page2, rotation, expand=False): """ This is similar to mergePage, but the stream to be merged is rotated by appling a transformation matrix. :param PageObject page2: the page to be merged into this one. Should be an instance of :class:`PageObject`. :param float rotation: The angle of the rotation, in degrees :param bool expand: Whether the page should be expanded to fit the dimensions of the page to be merged. """ rotation = math.radians(rotation) return self.mergeTransformedPage(page2, [math.cos(rotation), math.sin(rotation), -math.sin(rotation), math.cos(rotation), 0, 0], expand) def mergeTranslatedPage(self, page2, tx, ty, expand=False): """ This is similar to mergePage, but the stream to be merged is translated by appling a transformation matrix. :param PageObject page2: the page to be merged into this one. Should be an instance of :class:`PageObject`. :param float tx: The translation on X axis :param float ty: The translation on Y axis :param bool expand: Whether the page should be expanded to fit the dimensions of the page to be merged. """ return self.mergeTransformedPage(page2, [1, 0, 0, 1, tx, ty], expand) def mergeRotatedTranslatedPage(self, page2, rotation, tx, ty, expand=False): """ This is similar to mergePage, but the stream to be merged is rotated and translated by appling a transformation matrix. :param PageObject page2: the page to be merged into this one. Should be an instance of :class:`PageObject`. :param float tx: The translation on X axis :param float ty: The translation on Y axis :param float rotation: The angle of the rotation, in degrees :param bool expand: Whether the page should be expanded to fit the dimensions of the page to be merged. """ translation = [[1, 0, 0], [0, 1, 0], [-tx, -ty, 1]] rotation = math.radians(rotation) rotating = [[math.cos(rotation), math.sin(rotation), 0], [-math.sin(rotation), math.cos(rotation), 0], [0, 0, 1]] rtranslation = [[1, 0, 0], [0, 1, 0], [tx, ty, 1]] ctm = utils.matrixMultiply(translation, rotating) ctm = utils.matrixMultiply(ctm, rtranslation) return self.mergeTransformedPage(page2, [ctm[0][0], ctm[0][1], ctm[1][0], ctm[1][1], ctm[2][0], ctm[2][1]], expand) def mergeRotatedScaledPage(self, page2, rotation, scale, expand=False): """ This is similar to mergePage, but the stream to be merged is rotated and scaled by appling a transformation matrix. :param PageObject page2: the page to be merged into this one. Should be an instance of :class:`PageObject`. :param float rotation: The angle of the rotation, in degrees :param float scale: The scaling factor :param bool expand: Whether the page should be expanded to fit the dimensions of the page to be merged. """ rotation = math.radians(rotation) rotating = [[math.cos(rotation), math.sin(rotation), 0], [-math.sin(rotation), math.cos(rotation), 0], [0, 0, 1]] scaling = [[scale, 0, 0], [0, scale, 0], [0, 0, 1]] ctm = utils.matrixMultiply(rotating, scaling) return self.mergeTransformedPage(page2, [ctm[0][0], ctm[0][1], ctm[1][0], ctm[1][1], ctm[2][0], ctm[2][1]], expand) def mergeScaledTranslatedPage(self, page2, scale, tx, ty, expand=False): """ This is similar to mergePage, but the stream to be merged is translated and scaled by appling a transformation matrix. :param PageObject page2: the page to be merged into this one. Should be an instance of :class:`PageObject`. :param float scale: The scaling factor :param float tx: The translation on X axis :param float ty: The translation on Y axis :param bool expand: Whether the page should be expanded to fit the dimensions of the page to be merged. """ translation = [[1, 0, 0], [0, 1, 0], [tx, ty, 1]] scaling = [[scale, 0, 0], [0, scale, 0], [0, 0, 1]] ctm = utils.matrixMultiply(scaling, translation) return self.mergeTransformedPage(page2, [ctm[0][0], ctm[0][1], ctm[1][0], ctm[1][1], ctm[2][0], ctm[2][1]], expand) def mergeRotatedScaledTranslatedPage(self, page2, rotation, scale, tx, ty, expand=False): """ This is similar to mergePage, but the stream to be merged is translated, rotated and scaled by appling a transformation matrix. :param PageObject page2: the page to be merged into this one. Should be an instance of :class:`PageObject`. :param float tx: The translation on X axis :param float ty: The translation on Y axis :param float rotation: The angle of the rotation, in degrees :param float scale: The scaling factor :param bool expand: Whether the page should be expanded to fit the dimensions of the page to be merged. """ translation = [[1, 0, 0], [0, 1, 0], [tx, ty, 1]] rotation = math.radians(rotation) rotating = [[math.cos(rotation), math.sin(rotation), 0], [-math.sin(rotation), math.cos(rotation), 0], [0, 0, 1]] scaling = [[scale, 0, 0], [0, scale, 0], [0, 0, 1]] ctm = utils.matrixMultiply(rotating, scaling) ctm = utils.matrixMultiply(ctm, translation) return self.mergeTransformedPage(page2, [ctm[0][0], ctm[0][1], ctm[1][0], ctm[1][1], ctm[2][0], ctm[2][1]], expand) ## # Applys a transformation matrix the page. # # @param ctm A 6 elements tuple containing the operands of the # transformation matrix def addTransformation(self, ctm): """ Applies a transformation matrix to the page. :param tuple ctm: A 6-element tuple containing the operands of the transformation matrix. """ originalContent = self.getContents() if originalContent is not None: newContent = PageObject._addTransformationMatrix( originalContent, self.pdf, ctm) newContent = PageObject._pushPopGS(newContent, self.pdf) self[NameObject('/Contents')] = newContent def scale(self, sx, sy): """ Scales a page by the given factors by appling a transformation matrix to its content and updating the page size. :param float sx: The scaling factor on horizontal axis. :param float sy: The scaling factor on vertical axis. """ self.addTransformation([sx, 0, 0, sy, 0, 0]) self.mediaBox = RectangleObject([ float(self.mediaBox.getLowerLeft_x()) * sx, float(self.mediaBox.getLowerLeft_y()) * sy, float(self.mediaBox.getUpperRight_x()) * sx, float(self.mediaBox.getUpperRight_y()) * sy]) if "/VP" in self: viewport = self["/VP"] if isinstance(viewport, ArrayObject): bbox = viewport[0]["/BBox"] else: bbox = viewport["/BBox"] scaled_bbox = RectangleObject([ float(bbox[0]) * sx, float(bbox[1]) * sy, float(bbox[2]) * sx, float(bbox[3]) * sy]) if isinstance(viewport, ArrayObject): self[NameObject("/VP")][NumberObject(0)][NameObject("/BBox")] = scaled_bbox else: self[NameObject("/VP")][NameObject("/BBox")] = scaled_bbox def scaleBy(self, factor): """ Scales a page by the given factor by appling a transformation matrix to its content and updating the page size. :param float factor: The scaling factor (for both X and Y axis). """ self.scale(factor, factor) def scaleTo(self, width, height): """ Scales a page to the specified dimentions by appling a transformation matrix to its content and updating the page size. :param float width: The new width. :param float height: The new heigth. """ sx = width / float(self.mediaBox.getUpperRight_x() - self.mediaBox.getLowerLeft_x ()) sy = height / float(self.mediaBox.getUpperRight_y() - self.mediaBox.getLowerLeft_y ()) self.scale(sx, sy) def compressContentStreams(self): """ Compresses the size of this page by joining all content streams and applying a FlateDecode filter. However, it is possible that this function will perform no action if content stream compression becomes "automatic" for some reason. """ content = self.getContents() if content is not None: if not isinstance(content, ContentStream): content = ContentStream(content, self.pdf) self[NameObject("/Contents")] = content.flateEncode() def extractText(self): """ Locate all text drawing commands, in the order they are provided in the content stream, and extract the text. This works well for some PDF files, but poorly for others, depending on the generator used. This will be refined in the future. Do not rely on the order of text coming out of this function, as it will change if this function is made more sophisticated. :return: a unicode string object. """ text = u_("") content = self["/Contents"].getObject() if not isinstance(content, ContentStream): content = ContentStream(content, self.pdf) # Note: we check all strings are TextStringObjects. ByteStringObjects # are strings where the byte->string encoding was unknown, so adding # them to the text here would be gibberish. for operands, operator in content.operations: if operator == b_("Tj"): _text = operands[0] if isinstance(_text, TextStringObject): text += _text elif operator == b_("T*"): text += "\n" elif operator == b_("'"): text += "\n" _text = operands[0] if isinstance(_text, TextStringObject): text += operands[0] elif operator == b_('"'): _text = operands[2] if isinstance(_text, TextStringObject): text += "\n" text += _text elif operator == b_("TJ"): for i in operands[0]: if isinstance(i, TextStringObject): text += i return text mediaBox = createRectangleAccessor("/MediaBox", ()) """ A :class:`RectangleObject`, expressed in default user space units, defining the boundaries of the physical medium on which the page is intended to be displayed or printed. """ cropBox = createRectangleAccessor("/CropBox", ("/MediaBox",)) """ A :class:`RectangleObject`, expressed in default user space units, defining the visible region of default user space. When the page is displayed or printed, its contents are to be clipped (cropped) to this rectangle and then imposed on the output medium in some implementation-defined manner. Default value: same as :attr:`mediaBox`. """ bleedBox = createRectangleAccessor("/BleedBox", ("/CropBox", "/MediaBox")) """ A :class:`RectangleObject`, expressed in default user space units, defining the region to which the contents of the page should be clipped when output in a production enviroment. """ trimBox = createRectangleAccessor("/TrimBox", ("/CropBox", "/MediaBox")) """ A :class:`RectangleObject`, expressed in default user space units, defining the intended dimensions of the finished page after trimming. """ artBox = createRectangleAccessor("/ArtBox", ("/CropBox", "/MediaBox")) """ A :class:`RectangleObject`, expressed in default user space units, defining the extent of the page's meaningful content as intended by the page's creator. """ class ContentStream(DecodedStreamObject): def __init__(self, stream, pdf): self.pdf = pdf self.operations = [] # stream may be a StreamObject or an ArrayObject containing # multiple StreamObjects to be cat'd together. stream = stream.getObject() if isinstance(stream, ArrayObject): data = b_("") for s in stream: data += s.getObject().getData() stream = BytesIO(b_(data)) else: stream = BytesIO(b_(stream.getData())) self.__parseContentStream(stream) def __parseContentStream(self, stream): # file("f:\\tmp.txt", "w").write(stream.read()) stream.seek(0, 0) operands = [] while True: peek = readNonWhitespace(stream) if peek == b_('') or ord_(peek) == 0: break stream.seek(-1, 1) if peek.isalpha() or peek == "'" or peek == '"': operator = utils.readUntilRegex(stream, NameObject.delimiterPattern, True) if operator == "BI": # begin inline image - a completely different parsing # mechanism is required, of course... thanks buddy... assert operands == [] ii = self._readInlineImage(stream) self.operations.append((ii, "INLINE IMAGE")) else: self.operations.append((operands, operator)) operands = [] elif peek == '%': # If we encounter a comment in the content stream, we have to # handle it here. Typically, readObject will handle # encountering a comment -- but readObject assumes that # following the comment must be the object we're trying to # read. In this case, it could be an operator instead. while peek not in ('\r', '\n'): peek = stream.read(1) else: operands.append(readObject(stream, None)) def _readInlineImage(self, stream): # begin reading just after the "BI" - begin image # first read the dictionary of settings. settings = DictionaryObject() while True: tok = readNonWhitespace(stream) stream.seek(-1, 1) if tok == "I": # "ID" - begin of image data break key = readObject(stream, self.pdf) tok = readNonWhitespace(stream) stream.seek(-1, 1) value = readObject(stream, self.pdf) settings[key] = value # left at beginning of ID tmp = stream.read(3) assert tmp[:2] == "ID" data = "" while True: tok = stream.read(1) if tok == "E": # Check for End Image next1 = stream.read(1) if next1 == "I": next2 = readNonWhitespace(stream) if next2 == 'Q': stream.seek(-1, 1) break else: stream.seek(-2, 1) data += tok else: stream.seek(-1, 1) data += tok else: data += tok x = readNonWhitespace(stream) stream.seek(-1, 1) return {"settings": settings, "data": data} def _getData(self): newdata = BytesIO() for operands, operator in self.operations: if operator == "INLINE IMAGE": newdata.write("BI") dicttext = StringIO() operands["settings"].writeToStream(dicttext, None) newdata.write(dicttext.getvalue()[2:-2]) newdata.write("ID ") newdata.write(operands["data"]) newdata.write("EI") else: for op in operands: op.writeToStream(newdata, None) newdata.write(b_(" ")) newdata.write(b_(operator)) newdata.write(b_("\n")) return newdata.getvalue() def _setData(self, value): self.__parseContentStream(BytesIO(b_(value))) _data = property(_getData, _setData) class DocumentInformation(DictionaryObject): """ A class representing the basic document metadata provided in a PDF File. This class is accessible through :meth:`getDocumentInfo()` All text properties of the document metadata have *two* properties, eg. author and author_raw. The non-raw property will always return a ``TextStringObject``, making it ideal for a case where the metadata is being displayed. The raw property can sometimes return a ``ByteStringObject``, if PyPDF2 was unable to decode the string's text encoding; this requires additional safety in the caller and therefore is not as commonly accessed. """ def __init__(self): DictionaryObject.__init__(self) def getText(self, key): retval = self.get(key, None) if isinstance(retval, TextStringObject): return retval return None title = property(lambda self: self.getText("/Title")) """Read-only property accessing the document's **title**. Returns a unicode string (``TextStringObject``) or ``None`` if the title is not specified.""" title_raw = property(lambda self: self.get("/Title")) """The "raw" version of title; can return a ``ByteStringObject``.""" author = property(lambda self: self.getText("/Author")) """Read-only property accessing the document's **author**. Returns a unicode string (``TextStringObject``) or ``None`` if the author is not specified.""" author_raw = property(lambda self: self.get("/Author")) """The "raw" version of author; can return a ``ByteStringObject``.""" subject = property(lambda self: self.getText("/Subject")) """Read-only property accessing the document's **subject**. Returns a unicode string (``TextStringObject``) or ``None`` if the subject is not specified.""" subject_raw = property(lambda self: self.get("/Subject")) """The "raw" version of subject; can return a ``ByteStringObject``.""" creator = property(lambda self: self.getText("/Creator")) """Read-only property accessing the document's **creator**. If the document was converted to PDF from another format, this is the name of the application (e.g. OpenOffice) that created the original document from which it was converted. Returns a unicode string (``TextStringObject``) or ``None`` if the creator is not specified.""" creator_raw = property(lambda self: self.get("/Creator")) """The "raw" version of creator; can return a ``ByteStringObject``.""" producer = property(lambda self: self.getText("/Producer")) """Read-only property accessing the document's **producer**. If the document was converted to PDF from another format, this is the name of the application (for example, OSX Quartz) that converted it to PDF. Returns a unicode string (``TextStringObject``) or ``None`` if the producer is not specified.""" producer_raw = property(lambda self: self.get("/Producer")) """The "raw" version of producer; can return a ``ByteStringObject``.""" def convertToInt(d, size): if size > 8: raise utils.PdfReadError("invalid size in convertToInt") d = b_("\x00\x00\x00\x00\x00\x00\x00\x00") + b_(d) d = d[-8:] return struct.unpack(">q", d)[0] # ref: pdf1.8 spec section 3.5.2 algorithm 3.2 _encryption_padding = b_('\x28\xbf\x4e\x5e\x4e\x75\x8a\x41\x64\x00\x4e\x56') + \ b_('\xff\xfa\x01\x08\x2e\x2e\x00\xb6\xd0\x68\x3e\x80\x2f\x0c') + \ b_('\xa9\xfe\x64\x53\x69\x7a') # Implementation of algorithm 3.2 of the PDF standard security handler, # section 3.5.2 of the PDF 1.6 reference. def _alg32(password, rev, keylen, owner_entry, p_entry, id1_entry, metadata_encrypt=True): # 1. Pad or truncate the password string to exactly 32 bytes. If the # password string is more than 32 bytes long, use only its first 32 bytes; # if it is less than 32 bytes long, pad it by appending the required number # of additional bytes from the beginning of the padding string # (_encryption_padding). password = b_((str_(password) + str_(_encryption_padding))[:32]) # 2. Initialize the MD5 hash function and pass the result of step 1 as # input to this function. import struct m = md5(password) # 3. Pass the value of the encryption dictionary's /O entry to the MD5 hash # function. m.update(owner_entry.original_bytes) # 4. Treat the value of the /P entry as an unsigned 4-byte integer and pass # these bytes to the MD5 hash function, low-order byte first. p_entry = struct.pack('= 3 and not metadata_encrypt: m.update(b_("\xff\xff\xff\xff")) # 7. Finish the hash. md5_hash = m.digest() # 8. (Revision 3 or greater) Do the following 50 times: Take the output # from the previous MD5 hash and pass the first n bytes of the output as # input into a new MD5 hash, where n is the number of bytes of the # encryption key as defined by the value of the encryption dictionary's # /Length entry. if rev >= 3: for i in range(50): md5_hash = md5(md5_hash[:keylen]).digest() # 9. Set the encryption key to the first n bytes of the output from the # final MD5 hash, where n is always 5 for revision 2 but, for revision 3 or # greater, depends on the value of the encryption dictionary's /Length # entry. return md5_hash[:keylen] # Implementation of algorithm 3.3 of the PDF standard security handler, # section 3.5.2 of the PDF 1.6 reference. def _alg33(owner_pwd, user_pwd, rev, keylen): # steps 1 - 4 key = _alg33_1(owner_pwd, rev, keylen) # 5. Pad or truncate the user password string as described in step 1 of # algorithm 3.2. user_pwd = b_((user_pwd + str_(_encryption_padding))[:32]) # 6. Encrypt the result of step 5, using an RC4 encryption function with # the encryption key obtained in step 4. val = utils.RC4_encrypt(key, user_pwd) # 7. (Revision 3 or greater) Do the following 19 times: Take the output # from the previous invocation of the RC4 function and pass it as input to # a new invocation of the function; use an encryption key generated by # taking each byte of the encryption key obtained in step 4 and performing # an XOR operation between that byte and the single-byte value of the # iteration counter (from 1 to 19). if rev >= 3: for i in range(1, 20): new_key = '' for l in range(len(key)): new_key += chr(ord_(key[l]) ^ i) val = utils.RC4_encrypt(new_key, val) # 8. Store the output from the final invocation of the RC4 as the value of # the /O entry in the encryption dictionary. return val # Steps 1-4 of algorithm 3.3 def _alg33_1(password, rev, keylen): # 1. Pad or truncate the owner password string as described in step 1 of # algorithm 3.2. If there is no owner password, use the user password # instead. password = b_((password + str_(_encryption_padding))[:32]) # 2. Initialize the MD5 hash function and pass the result of step 1 as # input to this function. m = md5(password) # 3. (Revision 3 or greater) Do the following 50 times: Take the output # from the previous MD5 hash and pass it as input into a new MD5 hash. md5_hash = m.digest() if rev >= 3: for i in range(50): md5_hash = md5(md5_hash).digest() # 4. Create an RC4 encryption key using the first n bytes of the output # from the final MD5 hash, where n is always 5 for revision 2 but, for # revision 3 or greater, depends on the value of the encryption # dictionary's /Length entry. key = md5_hash[:keylen] return key # Implementation of algorithm 3.4 of the PDF standard security handler, # section 3.5.2 of the PDF 1.6 reference. def _alg34(password, owner_entry, p_entry, id1_entry): # 1. Create an encryption key based on the user password string, as # described in algorithm 3.2. key = _alg32(password, 2, 5, owner_entry, p_entry, id1_entry) # 2. Encrypt the 32-byte padding string shown in step 1 of algorithm 3.2, # using an RC4 encryption function with the encryption key from the # preceding step. U = utils.RC4_encrypt(key, _encryption_padding) # 3. Store the result of step 2 as the value of the /U entry in the # encryption dictionary. return U, key # Implementation of algorithm 3.4 of the PDF standard security handler, # section 3.5.2 of the PDF 1.6 reference. def _alg35(password, rev, keylen, owner_entry, p_entry, id1_entry, metadata_encrypt): # 1. Create an encryption key based on the user password string, as # described in Algorithm 3.2. key = _alg32(password, rev, keylen, owner_entry, p_entry, id1_entry) # 2. Initialize the MD5 hash function and pass the 32-byte padding string # shown in step 1 of Algorithm 3.2 as input to this function. m = md5() m.update(_encryption_padding) # 3. Pass the first element of the file's file identifier array (the value # of the ID entry in the document's trailer dictionary; see Table 3.13 on # page 73) to the hash function and finish the hash. (See implementation # note 25 in Appendix H.) m.update(id1_entry.original_bytes) md5_hash = m.digest() # 4. Encrypt the 16-byte result of the hash, using an RC4 encryption # function with the encryption key from step 1. val = utils.RC4_encrypt(key, md5_hash) # 5. Do the following 19 times: Take the output from the previous # invocation of the RC4 function and pass it as input to a new invocation # of the function; use an encryption key generated by taking each byte of # the original encryption key (obtained in step 2) and performing an XOR # operation between that byte and the single-byte value of the iteration # counter (from 1 to 19). for i in range(1, 20): new_key = b_('') for l in range(len(key)): new_key += b_(chr(ord_(key[l]) ^ i)) val = utils.RC4_encrypt(new_key, val) # 6. Append 16 bytes of arbitrary padding to the output from the final # invocation of the RC4 function and store the 32-byte result as the value # of the U entry in the encryption dictionary. # (implementator note: I don't know what "arbitrary padding" is supposed to # mean, so I have used null bytes. This seems to match a few other # people's implementations) return val + (b_('\x00') * 16), key