Exemplo n.º 1
0
    def addBookmark(self, title, pagenum, parent=None):
        """
        Add a bookmark to the pdf, using the specified title and pointing at
        the specified page number. A parent can be specified to make this a
        nested bookmark below the parent.
        """
        pageRef = self.getObject(self._pages)['/Kids'][pagenum]
        action = DictionaryObject()
        action.update({NameObject('/D'): ArrayObject([pageRef,
                                                      NameObject('/FitH'),
                                                      NumberObject(826)]),
                       NameObject('/S'): NameObject('/GoTo')})
        actionRef = self._addObject(action)

        outlineRef = self.getOutlineRoot()
        if parent is None:
            parent = outlineRef
        bookmark = TreeObject()
        bookmark.update({NameObject('/A'): actionRef,
                         NameObject('/Title'): createStringObject(title)})
        bookmarkRef = self._addObject(bookmark)

        parent = parent.getObject()
        parent.addChild(bookmarkRef, self)
        return bookmarkRef
Exemplo n.º 2
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    def addBookmark(self, title, pagenum, parent=None):
        """
        Add a bookmark to the pdf, using the specified title and pointing at
        the specified page number. A parent can be specified to make this a
        nested bookmark below the parent.
        """
        pageRef = self.getObject(self._pages)['/Kids'][pagenum]
        action = DictionaryObject()
        action.update({
            NameObject('/D'):
            ArrayObject([pageRef,
                         NameObject('/FitH'),
                         NumberObject(826)]),
            NameObject('/S'):
            NameObject('/GoTo')
        })
        actionRef = self._addObject(action)

        outlineRef = self.getOutlineRoot()
        if parent is None:
            parent = outlineRef
        bookmark = TreeObject()
        bookmark.update({
            NameObject('/A'): actionRef,
            NameObject('/Title'): createStringObject(title)
        })
        bookmarkRef = self._addObject(bookmark)

        parent = parent.getObject()
        parent.addChild(bookmarkRef, self)
        return bookmarkRef
Exemplo n.º 3
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    def getNamedDestRoot(self):
        root = self.getObject(self._root)

        if '/Names' in root and isinstance(root['/Names'], DictionaryObject):
            names = root['/Names']
            idnum = self._objects.index(names) + 1
            namesRef = IndirectObject(idnum, 0, self)
            assert namesRef.getObject() == names
            if '/Dests' in names and isinstance(names['/Dests'],
                                                DictionaryObject):
                dests = names['/Dests']
                idnum = self._objects.index(dests) + 1
                destsRef = IndirectObject(idnum, 0, self)
                assert destsRef.getObject() == dests
                if '/Names' in dests:
                    nd = dests['/Names']
                else:
                    nd = ArrayObject()
                    dests[NameObject('/Names')] = nd
            else:
                dests = DictionaryObject()
                destsRef = self._addObject(dests)
                names[NameObject('/Dests')] = destsRef
                nd = ArrayObject()
                dests[NameObject('/Names')] = nd
        else:
            names = DictionaryObject()
            namesRef = self._addObject(names)
            root[NameObject('/Names')] = namesRef
            dests = DictionaryObject()
            destsRef = self._addObject(dests)
            names[NameObject('/Dests')] = destsRef
            nd = ArrayObject()
            dests[NameObject('/Names')] = nd
        return nd
Exemplo n.º 4
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    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
Exemplo n.º 5
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 def add(self, title, pagenum):
     pageRef = self.pdf.getObject(self.pdf._pages)['/Kids'][pagenum]
     action = DictionaryObject()
     action.update({NameObject('/D'): ArrayObject([pageRef,
                                                   NameObject('/FitH'),
                                                   NumberObject(826)]),
                    NameObject('/S'): NameObject('/GoTo')})
     actionRef = self.pdf._addObject(action)
     bookmark = TreeObject()
     bookmark.update({NameObject('/A'): actionRef,
                      NameObject('/Title'): createStringObject(title)})
     self.pdf._addObject(bookmark)
     self.tree.addChild(bookmark)
Exemplo n.º 6
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 def _mergeResources(res1, res2, resource):
     newRes = DictionaryObject()
     newRes.update(res1.get(resource, DictionaryObject()).getObject())
     page2Res = res2.get(resource, DictionaryObject()).getObject()
     renameRes = {}
     for key in page2Res.keys():
         if key in newRes and newRes[key] != page2Res[key]:
             newname = NameObject(key + "renamed")
             renameRes[key] = newname
             newRes[newname] = page2Res[key]
         elif key not in newRes:
             newRes[key] = page2Res.raw_get(key)
     return newRes, renameRes
Exemplo n.º 7
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    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
Exemplo n.º 8
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 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":
             next = stream.read(1)
             if next == "I":
                 break
             else:
                 stream.seek(-1, 1)
                 data += tok
         else:
             data += tok
     readNonWhitespace(stream)
     stream.seek(-1, 1)
     return {"settings": settings, "data": data}
Exemplo n.º 9
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    def __init__(self, title, page, typ, *args):
        DictionaryObject.__init__(self)
        self[NameObject("/Title")] = title
        self[NameObject("/Page")] = page
        self[NameObject("/Type")] = typ

        # from table 8.2 of the PDF 1.6 reference.
        if typ == "/XYZ":
            (self[NameObject("/Left")], self[NameObject("/Top")],
                self[NameObject("/Zoom")]) = args
        elif typ == "/FitR":
            (self[NameObject("/Left")], self[NameObject("/Bottom")],
                self[NameObject("/Right")], self[NameObject("/Top")]) = args
        elif typ in ["/FitH", "FitBH"]:
            self[NameObject("/Top")], = args
        elif typ in ["/FitV", "FitBV"]:
            self[NameObject("/Left")], = args
        elif typ in ["/Fit", "FitB"]:
            pass
        else:
            raise utils.PdfReadError("Unknown Destination Type: %r" % typ)
Exemplo n.º 10
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 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(
         u"Python PDF Library - http://pybrary.net/pyPdf/")})
     self._info = self._addObject(info)
     # root object
     root = DictionaryObject()
     root.update({NameObject("/Type"): NameObject("/Catalog"),
                  NameObject("/Pages"): self._pages})
     self._root = self._addObject(root)
Exemplo n.º 11
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 def addBookmarkDict(self, bookmark, parent=None):
     bookmarkObj = TreeObject()
     for k, v in bookmark.items():
         bookmarkObj[NameObject(str(k))] = v
     bookmarkObj.update(bookmark)
     if '/A' in bookmark:
         action = DictionaryObject()
         for k, v in bookmark['/A'].items():
             action[NameObject(str(k))] = v
         actionRef = self._addObject(action)
         bookmarkObj['/A'] = actionRef
     bookmarkRef = self._addObject(bookmarkObj)
     outlineRef = self.getOutlineRoot()
     if parent is None:
         parent = outlineRef
     parent = parent.getObject()
     parent.addChild(bookmarkRef, self)
     return bookmarkRef
Exemplo n.º 12
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    def createBlankPage(pdf=None, width=None, height=None):
        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
Exemplo n.º 13
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 def _mergeResources(res1, res2, resource):
     newRes = DictionaryObject()
     newRes.update(res1.get(resource, DictionaryObject()).getObject())
     page2Res = res2.get(resource, DictionaryObject()).getObject()
     renameRes = {}
     for key in page2Res.keys():
         if key in newRes and newRes[key] != page2Res[key]:
             newname = NameObject(key + "renamed")
             renameRes[key] = newname
             newRes[newname] = page2Res[key]
         elif key not in newRes:
             newRes[key] = page2Res.raw_get(key)
     return newRes, renameRes
Exemplo n.º 14
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 def encrypt(self, user_pwd, owner_pwd=None, use_128bit=True):
     import time
     import random
     if owner_pwd is None:
         owner_pwd = user_pwd
     if use_128bit:
         V = 2
         rev = 3
         keylen = 128 / 8
     else:
         V = 1
         rev = 2
         keylen = 40 / 8
     # permit everything:
     P = -1
     O = ByteStringObject(_alg33(owner_pwd, user_pwd, rev, keylen))
     ID_1 = md5(repr(time.time())).digest()
     ID_2 = md5(repr(random.random())).digest()
     self._ID = ArrayObject(
         (ByteStringObject(ID_1), ByteStringObject(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
Exemplo n.º 15
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    def read(self, stream):
        # start at the end:
        stream.seek(-1, 2)
        line = b_('')
        while not line:
            line = self.readNextEndLine(stream)
        if line[:5] != b_("%%EOF"):
            raise utils.PdfReadError, "EOF marker not found"
        # find startxref entry - the location of the xref table
        line = self.readNextEndLine(stream)
        startxref = int(line)
        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 1:
            # 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)
                # check if the first time looking at the xref table
                firsttime = True
                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)
                        self.xref.setdefault(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 newTrailer.items():
                    self.trailer.setdefault(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 = StringIO(xrefstream.getData())
                idx_pairs = xrefstream.get("/Index",
                                           [0, xrefstream.get("/Size")])
                entrySizes = xrefstream.get("/W")
                for num, size in self._pairs(idx_pairs):
                    cnt = 0
                    while cnt < size:
                        for i in range(len(entrySizes)):
                            d = streamData.read(entrySizes[i])
                            di = convertToInt(d, entrySizes[i])
                            if i == 0:
                                xref_type = di
                            elif i == 1:
                                if xref_type == 0:
                                    # next_free_object = di
                                    pass
                                elif xref_type == 1:
                                    byte_offset = di
                                elif xref_type == 2:
                                    objstr_num = di
                            elif i == 2:
                                if xref_type == 0:
                                    # next_generation = di
                                    pass
                                elif xref_type == 1:
                                    generation = di
                                elif xref_type == 2:
                                    obstr_idx = di
                        if xref_type == 0:
                            pass
                        elif xref_type == 1:
                            if generation not in self.xref:
                                self.xref[generation] = {}
                            if not num in self.xref[generation]:
                                self.xref[generation][num] = byte_offset
                        elif xref_type == 2:
                            if not num in self.xref_objStm:
                                self.xref_objStm[num] = [objstr_num, obstr_idx]
                        cnt += 1
                        num += 1
                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
                else:
                    # 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)
                    pid, pgen = self.readObjectHeader(stream)
                    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
Exemplo n.º 16
0
    def read(self, stream):
        # start at the end:
        stream.seek(-1, 2)
        line = b_('')
        while not line:
            line = self.readNextEndLine(stream)
        if line[:5] != b_("%%EOF"):
            raise utils.PdfReadError, "EOF marker not found"
        # find startxref entry - the location of the xref table
        line = self.readNextEndLine(stream)
        startxref = int(line)
        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 1:
            # 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)
                # check if the first time looking at the xref table
                firsttime = True
                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)
                        self.xref.setdefault(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 newTrailer.items():
                    self.trailer.setdefault(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 = StringIO(xrefstream.getData())
                idx_pairs = xrefstream.get("/Index",
                                           [0, xrefstream.get("/Size")])
                entrySizes = xrefstream.get("/W")
                for num, size in self._pairs(idx_pairs):
                    cnt = 0
                    while cnt < size:
                        for i in range(len(entrySizes)):
                            d = streamData.read(entrySizes[i])
                            di = convertToInt(d, entrySizes[i])
                            if i == 0:
                                xref_type = di
                            elif i == 1:
                                if xref_type == 0:
                                    # next_free_object = di
                                    pass
                                elif xref_type == 1:
                                    byte_offset = di
                                elif xref_type == 2:
                                    objstr_num = di
                            elif i == 2:
                                if xref_type == 0:
                                    # next_generation = di
                                    pass
                                elif xref_type == 1:
                                    generation = di
                                elif xref_type == 2:
                                    obstr_idx = di
                        if xref_type == 0:
                            pass
                        elif xref_type == 1:
                            if generation not in self.xref:
                                self.xref[generation] = {}
                            if not num in self.xref[generation]:
                                self.xref[generation][num] = byte_offset
                        elif xref_type == 2:
                            if not num in self.xref_objStm:
                                self.xref_objStm[num] = [objstr_num, obstr_idx]
                        cnt += 1
                        num += 1
                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
                else:
                    # 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)
                    pid, pgen = self.readObjectHeader(stream)
                    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
Exemplo n.º 17
0
 def __init__(self, pdf=None, indirectRef=None):
     DictionaryObject.__init__(self)
     self.pdf = pdf
     # Stores the original indirect reference
     # to this object in its source PDF
     self.indirectRef = indirectRef
Exemplo n.º 18
0
 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(
             u"Python PDF Library - http://pybrary.net/pyPdf/")
     })
     self._info = self._addObject(info)
     # root object
     root = DictionaryObject()
     root.update({
         NameObject("/Type"): NameObject("/Catalog"),
         NameObject("/Pages"): self._pages
     })
     self._root = self._addObject(root)
Exemplo n.º 19
0
class PdfFileReader(object):
    def __init__(self, stream, strict=True, warndest=None):
        # have to dynamically override the default show
        # warning 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(
                    warnings.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 (str, unicode):
            fileobj = open(stream, 'rb')
            stream = StringIO(fileobj.read())
            fileobj.close()
        self.read(stream)
        self.stream = stream
        self._override_encryption = False

    ##
    # 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.
    # <p>
    # Stability: Added in v1.6, will exist for all future v1.x releases.
    # @return Returns a {@link #DocumentInformation DocumentInformation}
    #         instance, or None if none exists.
    def getDocumentInfo(self):
        if "/Info" not in self.trailer:
            return None
        obj = self.trailer['/Info']
        retval = DocumentInformation()
        retval.update(obj)
        return retval

    ##
    # Read-only property that accesses the {@link
    # #PdfFileReader.getDocumentInfo getDocumentInfo} function.
    # <p>
    # Stability: Added in v1.7, will exist for all future v1.x releases.
    documentInfo = property(lambda self: self.getDocumentInfo(), None, None)

    ##
    # Retrieves XMP (Extensible Metadata Platform) data from the PDF document
    # root.
    # <p>
    # Stability: Added in v1.12, will exist for all future v1.x releases.
    # @return Returns a {@link #generic.XmpInformation XmlInformation}
    # instance that can be used to access XMP metadata from the document.
    # Can also return None if no metadata was found on the document root.
    def getXmpMetadata(self):
        try:
            self._override_encryption = True
            return self.trailer["/Root"].getXmpMetadata()
        finally:
            self._override_encryption = False

    ##
    # Read-only property that accesses the {@link #PdfFileReader.getXmpData
    # getXmpData} function.
    # <p>
    # Stability: Added in v1.12, will exist for all future v1.x releases.
    xmpMetadata = property(lambda self: self.getXmpMetadata(), None, None)

    ##
    # Calculates the number of pages in this PDF file.
    # <p>
    # Stability: Added in v1.0, will exist for all v1.x releases.
    # @return Returns an integer.
    def getNumPages(self):
        # 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"]
            finally:
                self._override_encryption = False
        else:
            if self.flattenedPages is None:
                self._flatten()
            return len(self.flattenedPages)

    ##
    # Read-only property that accesses the {@link #PdfFileReader.getNumPages
    # getNumPages} function.
    # <p>
    # Stability: Added in v1.7, will exist for all future v1.x releases.
    numPages = property(lambda self: self.getNumPages(), None, None)

    ##
    # Retrieves a page by number from this PDF file.
    # <p>
    # Stability: Added in v1.0, will exist for all v1.x releases.
    # @return Returns a {@link #PageObject PageObject} instance.
    def getPage(self, pageNumber):
        ## ensure that we're not trying to access an encrypted PDF
        #assert not self.trailer.has_key("/Encrypt")
        if self.flattenedPages is None:
            self._flatten()
        return self.flattenedPages[pageNumber]

    ##
    # Read-only property that accesses the
    # {@link #PdfFileReader.getNamedDestinations
    # getNamedDestinations} function.
    # <p>
    # Stability: Added in v1.10, will exist for all future v1.x releases.
    namedDestinations = property(lambda self: self.getNamedDestinations(),
                                 None, None)

    ##
    # Retrieves the named destinations present in the document.
    # <p>
    # Stability: Added in v1.10, will exist for all future v1.x releases.
    # @return Returns a dict which maps names to {@link #Destination
    # destinations}.
    def getNamedDestinations(self, tree=None, retval=None):
        if retval is 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 is 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 is not None:
                    retval[key] = dest

        return retval

    ##
    # Read-only property that accesses the {@link #PdfFileReader.getOutlines
    # getOutlines} function.
    # <p>
    # Stability: Added in v1.10, will exist for all future v1.x releases.
    outlines = property(lambda self: self.getOutlines(), None, None)

    ##
    # Retrieves the document outline present in the document.
    # <p>
    # Stability: Added in v1.10, will exist for all future v1.x releases.
    # @return Returns a nested list of {@link #Destination destinations}.
    def getOutlines(self, node=None, outlines=None):
        if outlines is 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 is None:
            return outlines
        # see if there are any more outlines
        while 1:
            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, unicode) and dest in self._namedDests:
                outline = self._namedDests[dest]
                outline[NameObject("/Title")] = title
            else:
                raise utils.PdfReadError("Unexpected destination %r" % dest)
        return outline

    ##
    # Read-only property that emulates a list based upon the {@link
    # #PdfFileReader.getNumPages getNumPages} and {@link #PdfFileReader.getPage
    # getPage} functions.
    # <p>
    # Stability: Added in v1.7, and will exist for all future v1.x releases.
    pages = property(
        lambda self: ConvertFunctionsToVirtualList(self.getNumPages, self.
                                                   getPage), None, None)

    def _flatten(self, pages=None, inherit=None, indirectRef=None):
        inheritablePageAttributes = (NameObject("/Resources"),
                                     NameObject("/MediaBox"),
                                     NameObject("/CropBox"),
                                     NameObject("/Rotate"))
        if inherit is None:
            inherit = dict()
        if pages is None:
            self.flattenedPages = []
            catalog = self.trailer["/Root"].getObject()
            pages = catalog["/Pages"].getObject()
        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 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 getObject(self, indirectReference):
        retval = self.resolvedObjects.get(indirectReference.generation,
                                          {}).get(indirectReference.idnum,
                                                  None)
        if retval is not None:
            return retval
        if indirectReference.generation == 0 \
                and indirectReference.idnum in self.xref_objStm:
            # indirect reference to object in object stream
            # read the entire object stream into memory
            stmnum, idx = self.xref_objStm[indirectReference.idnum]
            objStm = IndirectObject(stmnum, 0, self).getObject()
            assert objStm['/Type'] == '/ObjStm'
            assert idx < objStm['/N']
            streamData = StringIO(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)
                t = streamData.tell()
                streamData.seek(objStm['/First'] + offset, 0)
                obj = readObject(streamData, self)
                self.resolvedObjects[0][objnum] = obj
                streamData.seek(t, 0)
            return self.resolvedObjects[0][indirectReference.idnum]
        if indirectReference.idnum \
                not in self.xref[indirectReference.generation]:
            warnings.warn(
                "Object %d %d not defined." %
                (indirectReference.idnum, indirectReference.generation),
                utils.PdfReadWarning)
            return None
        start = self.xref[indirectReference.generation][
            indirectReference.idnum]
        self.stream.seek(start, 0)
        idnum, generation = self.readObjectHeader(self.stream)
        try:
            assert idnum == indirectReference.idnum
        except AssertionError:
            if 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:
                    # should not happen since the xref table is corrected in
                    # non-strict mode
                    pass
            else:  # 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 Exception("file has not been decrypted")
            # otherwise, decrypt here...
            pack1 = struct.pack("<i", indirectReference.idnum)[:3]
            pack2 = struct.pack("<i", indirectReference.generation)[:2]
            key = self._decryption_key + pack1 + pack2
            assert len(key) == (len(self._decryption_key) + 5)
            md5_hash = md5(key).digest()
            key = md5_hash[:min(16, len(self._decryption_key) + 5)]
            retval = self._decryptObject(retval, key)

        self.cacheIndirectObject(generation, idnum, retval)
        return retval

    def _decryptObject(self, obj, key):
        if isinstance(obj, ByteStringObject) \
                or isinstance(obj, TextStringObject):
            obj = createStringObject(utils.RC4_encrypt(key,
                                                       obj.original_bytes))
        elif isinstance(obj, StreamObject):
            obj._data = utils.RC4_encrypt(key, obj._data)
        elif isinstance(obj, DictionaryObject):
            for dictkey, value in obj.items():
                obj[dictkey] = self._decryptObject(value, key)
        elif isinstance(obj, ArrayObject):
            for i in range(len(obj)):
                obj[i] = self._decryptObject(obj[i], key)
        return obj

    def readObjectHeader(self, stream):
        # Should never be necessary to read out whitespace, since the
        # cross-reference table should put us in the right spot to read the
        # object header.  In reality... some files have stupid cross reference
        # tables that are off by whitespace bytes.
        extra = False
        utils.skipOverComment(stream)

        extra |= utils.skipOverWhitespace(stream)
        stream.seek(-1, 1)

        idnum = readUntilWhitespace(stream)

        extra |= utils.skipOverWhitespace(stream)
        stream.seek(-1, 1)

        generation = readUntilWhitespace(stream)
        stream.read(3)
        readNonWhitespace(stream)
        stream.seek(-1, 1)
        if (extra and self.strict):
            #not a fatal error
            warnings.warn(
                "Superfluous whitespace found in "
                "object header %s %s" % (idnum, generation),
                utils.PdfReadWarning)
        return int(idnum), int(generation)

    def cacheIndirectObject(self, generation, idnum, obj):
        self.resolvedObjects.setdefault(generation, {})
        self.resolvedObjects[generation][idnum] = obj

    def read(self, stream):
        # start at the end:
        stream.seek(-1, 2)
        line = b_('')
        while not line:
            line = self.readNextEndLine(stream)
        if line[:5] != b_("%%EOF"):
            raise utils.PdfReadError, "EOF marker not found"
        # find startxref entry - the location of the xref table
        line = self.readNextEndLine(stream)
        startxref = int(line)
        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 1:
            # 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)
                # check if the first time looking at the xref table
                firsttime = True
                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)
                        self.xref.setdefault(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 newTrailer.items():
                    self.trailer.setdefault(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 = StringIO(xrefstream.getData())
                idx_pairs = xrefstream.get("/Index",
                                           [0, xrefstream.get("/Size")])
                entrySizes = xrefstream.get("/W")
                for num, size in self._pairs(idx_pairs):
                    cnt = 0
                    while cnt < size:
                        for i in range(len(entrySizes)):
                            d = streamData.read(entrySizes[i])
                            di = convertToInt(d, entrySizes[i])
                            if i == 0:
                                xref_type = di
                            elif i == 1:
                                if xref_type == 0:
                                    # next_free_object = di
                                    pass
                                elif xref_type == 1:
                                    byte_offset = di
                                elif xref_type == 2:
                                    objstr_num = di
                            elif i == 2:
                                if xref_type == 0:
                                    # next_generation = di
                                    pass
                                elif xref_type == 1:
                                    generation = di
                                elif xref_type == 2:
                                    obstr_idx = di
                        if xref_type == 0:
                            pass
                        elif xref_type == 1:
                            if generation not in self.xref:
                                self.xref[generation] = {}
                            if not num in self.xref[generation]:
                                self.xref[generation][num] = byte_offset
                        elif xref_type == 2:
                            if not num in self.xref_objStm:
                                self.xref_objStm[num] = [objstr_num, obstr_idx]
                        cnt += 1
                        num += 1
                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
                else:
                    # 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)
                    pid, pgen = self.readObjectHeader(stream)
                    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 self.xref[generation].iteritems())

    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):
        line = b_("")
        while True:
            x = stream.read(1)
            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'):
                    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)
                # if using CR+LF, go back 2 bytes, else 1
                stream.seek(2 if crlf else 1, 1)
                break
            else:
                line = x + line
        return line

    ##
    # 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.
    # <p>
    # 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.
    # <p>
    # Stability: Added in v1.8, will exist for all future v1.x releases.
    #
    # @return 0 if the password failed, 1 if the password matched the user
    # password, and 2 if the password matched the owner password.
    #
    # @exception NotImplementedError Document uses an unsupported encryption
    # method.
    def decrypt(self, password):
        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().original_bytes
        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

    ##
    # Read-only boolean property showing whether this PDF file is encrypted.
    # Note that this property, if true, will remain true even after the {@link
    # #PdfFileReader.decrypt decrypt} function is called.
    isEncrypted = property(lambda self: self.getIsEncrypted(), None, None)
Exemplo n.º 20
0
 def __init__(self, pdf=None, indirectRef=None):
     DictionaryObject.__init__(self)
     self.pdf = pdf
     # Stores the original indirect reference
     # to this object in its source PDF
     self.indirectRef = indirectRef
Exemplo n.º 21
0
    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()

        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:
                new_x = map(
                    lambda i: ctm[0] * corners2[i] + ctm[2] * corners2[i + 1] +
                    ctm[4], range(0, 8, 2))
                new_y = map(
                    lambda i: ctm[1] * corners2[i] + ctm[3] * corners2[i + 1] +
                    ctm[5], 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
Exemplo n.º 22
0
    def write(self, stream):
        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 xrange(len(self._objects)):
            obj = self._objects[objIndex]
            if isinstance(obj, PageObject) and obj.indirectRef is not None:
                data = obj.indirectRef
                externalReferenceMap.setdefault(data.pdf, {})
                externalReferenceMap[data.pdf].setdefault(data.generation, {})
                externalReferenceMap[data.pdf][data.generation][data.idnum] = \
                    IndirectObject(objIndex + 1, 0, self)

        self.stack = []
        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("<i", i + 1)[:3]
                pack2 = struct.pack("<i", 0)[:2]
                key = self._encrypt_key + pack1 + pack2
                assert len(key) == (len(self._encrypt_key) + 5)
                md5_hash = md5(key).digest()
                key = md5_hash[:min(16, len(self._encrypt_key) + 5)]
            if obj is not None:
                obj.writeToStream(stream, key)
                stream.write(b_("\nendobj\n"))

        # xref table
        xref_location = stream.tell()
        stream.write(b_("xref\n"))
        stream.write(b_("0 %s\n" % (len(self._objects) + 1)))
        stream.write(b_("%010d %05d f \n" % (0, 65535)))
        for offset in object_positions:
            stream.write(b_("%010d %05d n \n" % (offset, 0)))

        # trailer
        stream.write(b_("trailer\n"))
        trailer = DictionaryObject()
        trailer.update({NameObject("/Size"): NumberObject(
            len(self._objects) + 1),
            NameObject("/Root"): self._root,
            NameObject("/Info"): self._info})
        if hasattr(self, "_ID"):
            trailer[NameObject("/ID")] = self._ID
        if hasattr(self, "_encrypt"):
            trailer[NameObject("/Encrypt")] = self._encrypt
        trailer.writeToStream(stream, None)

        # eof
        stream.write(b_("\nstartxref\n%s\n%%%%EOF\n" % (xref_location)))
Exemplo n.º 23
0
    def write(self, stream):
        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 xrange(len(self._objects)):
            obj = self._objects[objIndex]
            if isinstance(obj, PageObject) and obj.indirectRef is not None:
                data = obj.indirectRef
                externalReferenceMap.setdefault(data.pdf, {})
                externalReferenceMap[data.pdf].setdefault(data.generation, {})
                externalReferenceMap[data.pdf][data.generation][data.idnum] = \
                    IndirectObject(objIndex + 1, 0, self)

        self.stack = []
        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("<i", i + 1)[:3]
                pack2 = struct.pack("<i", 0)[:2]
                key = self._encrypt_key + pack1 + pack2
                assert len(key) == (len(self._encrypt_key) + 5)
                md5_hash = md5(key).digest()
                key = md5_hash[:min(16, len(self._encrypt_key) + 5)]
            if obj is not None:
                obj.writeToStream(stream, key)
                stream.write(b_("\nendobj\n"))

        # xref table
        xref_location = stream.tell()
        stream.write(b_("xref\n"))
        stream.write(b_("0 %s\n" % (len(self._objects) + 1)))
        stream.write(b_("%010d %05d f \n" % (0, 65535)))
        for offset in object_positions:
            stream.write(b_("%010d %05d n \n" % (offset, 0)))

        # trailer
        stream.write(b_("trailer\n"))
        trailer = DictionaryObject()
        trailer.update({
            NameObject("/Size"):
            NumberObject(len(self._objects) + 1),
            NameObject("/Root"):
            self._root,
            NameObject("/Info"):
            self._info
        })
        if hasattr(self, "_ID"):
            trailer[NameObject("/ID")] = self._ID
        if hasattr(self, "_encrypt"):
            trailer[NameObject("/Encrypt")] = self._encrypt
        trailer.writeToStream(stream, None)

        # eof
        stream.write(b_("\nstartxref\n%s\n%%%%EOF\n" % (xref_location)))
Exemplo n.º 24
0
class PdfFileReader(object):
    def __init__(self, stream, strict=True, warndest=None):
        # have to dynamically override the default show
        # warning 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(warnings.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 (str, unicode):
            fileobj = open(stream, 'rb')
            stream = StringIO(fileobj.read())
            fileobj.close()
        self.read(stream)
        self.stream = stream
        self._override_encryption = False

    ##
    # 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.
    # <p>
    # Stability: Added in v1.6, will exist for all future v1.x releases.
    # @return Returns a {@link #DocumentInformation DocumentInformation}
    #         instance, or None if none exists.
    def getDocumentInfo(self):
        if "/Info" not in self.trailer:
            return None
        obj = self.trailer['/Info']
        retval = DocumentInformation()
        retval.update(obj)
        return retval

    ##
    # Read-only property that accesses the {@link
    # #PdfFileReader.getDocumentInfo getDocumentInfo} function.
    # <p>
    # Stability: Added in v1.7, will exist for all future v1.x releases.
    documentInfo = property(lambda self: self.getDocumentInfo(), None, None)

    ##
    # Retrieves XMP (Extensible Metadata Platform) data from the PDF document
    # root.
    # <p>
    # Stability: Added in v1.12, will exist for all future v1.x releases.
    # @return Returns a {@link #generic.XmpInformation XmlInformation}
    # instance that can be used to access XMP metadata from the document.
    # Can also return None if no metadata was found on the document root.
    def getXmpMetadata(self):
        try:
            self._override_encryption = True
            return self.trailer["/Root"].getXmpMetadata()
        finally:
            self._override_encryption = False

    ##
    # Read-only property that accesses the {@link #PdfFileReader.getXmpData
    # getXmpData} function.
    # <p>
    # Stability: Added in v1.12, will exist for all future v1.x releases.
    xmpMetadata = property(lambda self: self.getXmpMetadata(), None, None)

    ##
    # Calculates the number of pages in this PDF file.
    # <p>
    # Stability: Added in v1.0, will exist for all v1.x releases.
    # @return Returns an integer.
    def getNumPages(self):
        # 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"]
            finally:
                self._override_encryption = False
        else:
            if self.flattenedPages is None:
                self._flatten()
            return len(self.flattenedPages)

    ##
    # Read-only property that accesses the {@link #PdfFileReader.getNumPages
    # getNumPages} function.
    # <p>
    # Stability: Added in v1.7, will exist for all future v1.x releases.
    numPages = property(lambda self: self.getNumPages(), None, None)

    ##
    # Retrieves a page by number from this PDF file.
    # <p>
    # Stability: Added in v1.0, will exist for all v1.x releases.
    # @return Returns a {@link #PageObject PageObject} instance.
    def getPage(self, pageNumber):
        ## ensure that we're not trying to access an encrypted PDF
        #assert not self.trailer.has_key("/Encrypt")
        if self.flattenedPages is None:
            self._flatten()
        return self.flattenedPages[pageNumber]

    ##
    # Read-only property that accesses the
    # {@link #PdfFileReader.getNamedDestinations
    # getNamedDestinations} function.
    # <p>
    # Stability: Added in v1.10, will exist for all future v1.x releases.
    namedDestinations = property(lambda self: self.getNamedDestinations(),
                                 None, None)

    ##
    # Retrieves the named destinations present in the document.
    # <p>
    # Stability: Added in v1.10, will exist for all future v1.x releases.
    # @return Returns a dict which maps names to {@link #Destination
    # destinations}.
    def getNamedDestinations(self, tree=None, retval=None):
        if retval is 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 is 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 is not None:
                    retval[key] = dest

        return retval

    ##
    # Read-only property that accesses the {@link #PdfFileReader.getOutlines
    # getOutlines} function.
    # <p>
    # Stability: Added in v1.10, will exist for all future v1.x releases.
    outlines = property(lambda self: self.getOutlines(), None, None)

    ##
    # Retrieves the document outline present in the document.
    # <p>
    # Stability: Added in v1.10, will exist for all future v1.x releases.
    # @return Returns a nested list of {@link #Destination destinations}.
    def getOutlines(self, node=None, outlines=None):
        if outlines is 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 is None:
            return outlines
        # see if there are any more outlines
        while 1:
            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, unicode) and dest in self._namedDests:
                outline = self._namedDests[dest]
                outline[NameObject("/Title")] = title
            else:
                raise utils.PdfReadError("Unexpected destination %r" % dest)
        return outline

    ##
    # Read-only property that emulates a list based upon the {@link
    # #PdfFileReader.getNumPages getNumPages} and {@link #PdfFileReader.getPage
    # getPage} functions.
    # <p>
    # Stability: Added in v1.7, and will exist for all future v1.x releases.
    pages = property(lambda self: ConvertFunctionsToVirtualList(
        self.getNumPages, self.getPage), None, None)

    def _flatten(self, pages=None, inherit=None, indirectRef=None):
        inheritablePageAttributes = (NameObject("/Resources"),
                                     NameObject("/MediaBox"),
                                     NameObject("/CropBox"),
                                     NameObject("/Rotate"))
        if inherit is None:
            inherit = dict()
        if pages is None:
            self.flattenedPages = []
            catalog = self.trailer["/Root"].getObject()
            pages = catalog["/Pages"].getObject()
        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 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 getObject(self, indirectReference):
        retval = self.resolvedObjects.get(indirectReference.generation,
                                          {}).get(indirectReference.idnum,
                                                  None)
        if retval is not None:
            return retval
        if indirectReference.generation == 0 \
                and indirectReference.idnum in self.xref_objStm:
            # indirect reference to object in object stream
            # read the entire object stream into memory
            stmnum, idx = self.xref_objStm[indirectReference.idnum]
            objStm = IndirectObject(stmnum, 0, self).getObject()
            assert objStm['/Type'] == '/ObjStm'
            assert idx < objStm['/N']
            streamData = StringIO(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)
                t = streamData.tell()
                streamData.seek(objStm['/First']+offset, 0)
                obj = readObject(streamData, self)
                self.resolvedObjects[0][objnum] = obj
                streamData.seek(t, 0)
            return self.resolvedObjects[0][indirectReference.idnum]
        if indirectReference.idnum \
                not in self.xref[indirectReference.generation]:
            warnings.warn("Object %d %d not defined." % (
                indirectReference.idnum, indirectReference.generation),
                utils.PdfReadWarning)
            return None
        start = self.xref[indirectReference.generation][
            indirectReference.idnum]
        self.stream.seek(start, 0)
        idnum, generation = self.readObjectHeader(self.stream)
        try:
            assert idnum == indirectReference.idnum
        except AssertionError:
            if 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:
                    # should not happen since the xref table is corrected in
                    # non-strict mode
                    pass
            else:  # 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 Exception("file has not been decrypted")
            # otherwise, decrypt here...
            pack1 = struct.pack("<i", indirectReference.idnum)[:3]
            pack2 = struct.pack("<i", indirectReference.generation)[:2]
            key = self._decryption_key + pack1 + pack2
            assert len(key) == (len(self._decryption_key) + 5)
            md5_hash = md5(key).digest()
            key = md5_hash[:min(16, len(self._decryption_key) + 5)]
            retval = self._decryptObject(retval, key)

        self.cacheIndirectObject(generation, idnum, retval)
        return retval

    def _decryptObject(self, obj, key):
        if isinstance(obj, ByteStringObject) \
                or isinstance(obj, TextStringObject):
            obj = createStringObject(utils.RC4_encrypt(key,
                                                       obj.original_bytes))
        elif isinstance(obj, StreamObject):
            obj._data = utils.RC4_encrypt(key, obj._data)
        elif isinstance(obj, DictionaryObject):
            for dictkey, value in obj.items():
                obj[dictkey] = self._decryptObject(value, key)
        elif isinstance(obj, ArrayObject):
            for i in range(len(obj)):
                obj[i] = self._decryptObject(obj[i], key)
        return obj

    def readObjectHeader(self, stream):
        # Should never be necessary to read out whitespace, since the
        # cross-reference table should put us in the right spot to read the
        # object header.  In reality... some files have stupid cross reference
        # tables that are off by whitespace bytes.
        extra = False
        utils.skipOverComment(stream)

        extra |= utils.skipOverWhitespace(stream)
        stream.seek(-1, 1)

        idnum = readUntilWhitespace(stream)

        extra |= utils.skipOverWhitespace(stream)
        stream.seek(-1, 1)

        generation = readUntilWhitespace(stream)
        stream.read(3)
        readNonWhitespace(stream)
        stream.seek(-1, 1)
        if (extra and self.strict):
            #not a fatal error
            warnings.warn("Superfluous whitespace found in "
                          "object header %s %s" % (idnum, generation),
                          utils.PdfReadWarning)
        return int(idnum), int(generation)

    def cacheIndirectObject(self, generation, idnum, obj):
        self.resolvedObjects.setdefault(generation, {})
        self.resolvedObjects[generation][idnum] = obj

    def read(self, stream):
        # start at the end:
        stream.seek(-1, 2)
        line = b_('')
        while not line:
            line = self.readNextEndLine(stream)
        if line[:5] != b_("%%EOF"):
            raise utils.PdfReadError, "EOF marker not found"
        # find startxref entry - the location of the xref table
        line = self.readNextEndLine(stream)
        startxref = int(line)
        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 1:
            # 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)
                # check if the first time looking at the xref table
                firsttime = True
                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)
                        self.xref.setdefault(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 newTrailer.items():
                    self.trailer.setdefault(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 = StringIO(xrefstream.getData())
                idx_pairs = xrefstream.get("/Index",
                                           [0, xrefstream.get("/Size")])
                entrySizes = xrefstream.get("/W")
                for num, size in self._pairs(idx_pairs):
                    cnt = 0
                    while cnt < size:
                        for i in range(len(entrySizes)):
                            d = streamData.read(entrySizes[i])
                            di = convertToInt(d, entrySizes[i])
                            if i == 0:
                                xref_type = di
                            elif i == 1:
                                if xref_type == 0:
                                    # next_free_object = di
                                    pass
                                elif xref_type == 1:
                                    byte_offset = di
                                elif xref_type == 2:
                                    objstr_num = di
                            elif i == 2:
                                if xref_type == 0:
                                    # next_generation = di
                                    pass
                                elif xref_type == 1:
                                    generation = di
                                elif xref_type == 2:
                                    obstr_idx = di
                        if xref_type == 0:
                            pass
                        elif xref_type == 1:
                            if generation not in self.xref:
                                self.xref[generation] = {}
                            if not num in self.xref[generation]:
                                self.xref[generation][num] = byte_offset
                        elif xref_type == 2:
                            if not num in self.xref_objStm:
                                self.xref_objStm[num] = [objstr_num, obstr_idx]
                        cnt += 1
                        num += 1
                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
                else:
                    # 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)
                    pid, pgen = self.readObjectHeader(stream)
                    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 self.xref[generation].iteritems())

    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):
        line = b_("")
        while True:
            x = stream.read(1)
            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'):
                    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)
                # if using CR+LF, go back 2 bytes, else 1
                stream.seek(2 if crlf else 1, 1)
                break
            else:
                line = x + line
        return line

    ##
    # 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.
    # <p>
    # 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.
    # <p>
    # Stability: Added in v1.8, will exist for all future v1.x releases.
    #
    # @return 0 if the password failed, 1 if the password matched the user
    # password, and 2 if the password matched the owner password.
    #
    # @exception NotImplementedError Document uses an unsupported encryption
    # method.
    def decrypt(self, password):
        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().original_bytes
        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

    ##
    # Read-only boolean property showing whether this PDF file is encrypted.
    # Note that this property, if true, will remain true even after the {@link
    # #PdfFileReader.decrypt decrypt} function is called.
    isEncrypted = property(lambda self: self.getIsEncrypted(), None, None)
Exemplo n.º 25
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 def __init__(self):
     DictionaryObject.__init__(self)