id card generator

1 files changed, 998 insertions, 0 deletions

diff --git a/env/lib/python3.10/site-packages/PIL/PdfParser.py b/env/lib/python3.10/site-packages/PIL/PdfParser.py
new file mode 100644
index 0000000..fd5cc5a
--- /dev/null
+++ b/env/lib/python3.10/site-packages/PIL/PdfParser.py
@@ -0,0 +1,998 @@
+import calendar
+import codecs
+import collections
+import mmap
+import os
+import re
+import time
+import zlib
+
+
+# see 7.9.2.2 Text String Type on page 86 and D.3 PDFDocEncoding Character Set
+# on page 656
+def encode_text(s):
+    return codecs.BOM_UTF16_BE + s.encode("utf_16_be")
+
+
+PDFDocEncoding = {
+    0x16: "\u0017",
+    0x18: "\u02D8",
+    0x19: "\u02C7",
+    0x1A: "\u02C6",
+    0x1B: "\u02D9",
+    0x1C: "\u02DD",
+    0x1D: "\u02DB",
+    0x1E: "\u02DA",
+    0x1F: "\u02DC",
+    0x80: "\u2022",
+    0x81: "\u2020",
+    0x82: "\u2021",
+    0x83: "\u2026",
+    0x84: "\u2014",
+    0x85: "\u2013",
+    0x86: "\u0192",
+    0x87: "\u2044",
+    0x88: "\u2039",
+    0x89: "\u203A",
+    0x8A: "\u2212",
+    0x8B: "\u2030",
+    0x8C: "\u201E",
+    0x8D: "\u201C",
+    0x8E: "\u201D",
+    0x8F: "\u2018",
+    0x90: "\u2019",
+    0x91: "\u201A",
+    0x92: "\u2122",
+    0x93: "\uFB01",
+    0x94: "\uFB02",
+    0x95: "\u0141",
+    0x96: "\u0152",
+    0x97: "\u0160",
+    0x98: "\u0178",
+    0x99: "\u017D",
+    0x9A: "\u0131",
+    0x9B: "\u0142",
+    0x9C: "\u0153",
+    0x9D: "\u0161",
+    0x9E: "\u017E",
+    0xA0: "\u20AC",
+}
+
+
+def decode_text(b):
+    if b[: len(codecs.BOM_UTF16_BE)] == codecs.BOM_UTF16_BE:
+        return b[len(codecs.BOM_UTF16_BE) :].decode("utf_16_be")
+    else:
+        return "".join(PDFDocEncoding.get(byte, chr(byte)) for byte in b)
+
+
+class PdfFormatError(RuntimeError):
+    """An error that probably indicates a syntactic or semantic error in the
+    PDF file structure"""
+
+    pass
+
+
+def check_format_condition(condition, error_message):
+    if not condition:
+        raise PdfFormatError(error_message)
+
+
+class IndirectReference(
+    collections.namedtuple("IndirectReferenceTuple", ["object_id", "generation"])
+):
+    def __str__(self):
+        return "%s %s R" % self
+
+    def __bytes__(self):
+        return self.__str__().encode("us-ascii")
+
+    def __eq__(self, other):
+        return (
+            other.__class__ is self.__class__
+            and other.object_id == self.object_id
+            and other.generation == self.generation
+        )
+
+    def __ne__(self, other):
+        return not (self == other)
+
+    def __hash__(self):
+        return hash((self.object_id, self.generation))
+
+
+class IndirectObjectDef(IndirectReference):
+    def __str__(self):
+        return "%s %s obj" % self
+
+
+class XrefTable:
+    def __init__(self):
+        self.existing_entries = {}  # object ID => (offset, generation)
+        self.new_entries = {}  # object ID => (offset, generation)
+        self.deleted_entries = {0: 65536}  # object ID => generation
+        self.reading_finished = False
+
+    def __setitem__(self, key, value):
+        if self.reading_finished:
+            self.new_entries[key] = value
+        else:
+            self.existing_entries[key] = value
+        if key in self.deleted_entries:
+            del self.deleted_entries[key]
+
+    def __getitem__(self, key):
+        try:
+            return self.new_entries[key]
+        except KeyError:
+            return self.existing_entries[key]
+
+    def __delitem__(self, key):
+        if key in self.new_entries:
+            generation = self.new_entries[key][1] + 1
+            del self.new_entries[key]
+            self.deleted_entries[key] = generation
+        elif key in self.existing_entries:
+            generation = self.existing_entries[key][1] + 1
+            self.deleted_entries[key] = generation
+        elif key in self.deleted_entries:
+            generation = self.deleted_entries[key]
+        else:
+            raise IndexError(
+                "object ID " + str(key) + " cannot be deleted because it doesn't exist"
+            )
+
+    def __contains__(self, key):
+        return key in self.existing_entries or key in self.new_entries
+
+    def __len__(self):
+        return len(
+            set(self.existing_entries.keys())
+            | set(self.new_entries.keys())
+            | set(self.deleted_entries.keys())
+        )
+
+    def keys(self):
+        return (
+            set(self.existing_entries.keys()) - set(self.deleted_entries.keys())
+        ) | set(self.new_entries.keys())
+
+    def write(self, f):
+        keys = sorted(set(self.new_entries.keys()) | set(self.deleted_entries.keys()))
+        deleted_keys = sorted(set(self.deleted_entries.keys()))
+        startxref = f.tell()
+        f.write(b"xref\n")
+        while keys:
+            # find a contiguous sequence of object IDs
+            prev = None
+            for index, key in enumerate(keys):
+                if prev is None or prev + 1 == key:
+                    prev = key
+                else:
+                    contiguous_keys = keys[:index]
+                    keys = keys[index:]
+                    break
+            else:
+                contiguous_keys = keys
+                keys = None
+            f.write(b"%d %d\n" % (contiguous_keys[0], len(contiguous_keys)))
+            for object_id in contiguous_keys:
+                if object_id in self.new_entries:
+                    f.write(b"%010d %05d n \n" % self.new_entries[object_id])
+                else:
+                    this_deleted_object_id = deleted_keys.pop(0)
+                    check_format_condition(
+                        object_id == this_deleted_object_id,
+                        f"expected the next deleted object ID to be {object_id}, "
+                        f"instead found {this_deleted_object_id}",
+                    )
+                    try:
+                        next_in_linked_list = deleted_keys[0]
+                    except IndexError:
+                        next_in_linked_list = 0
+                    f.write(
+                        b"%010d %05d f \n"
+                        % (next_in_linked_list, self.deleted_entries[object_id])
+                    )
+        return startxref
+
+
+class PdfName:
+    def __init__(self, name):
+        if isinstance(name, PdfName):
+            self.name = name.name
+        elif isinstance(name, bytes):
+            self.name = name
+        else:
+            self.name = name.encode("us-ascii")
+
+    def name_as_str(self):
+        return self.name.decode("us-ascii")
+
+    def __eq__(self, other):
+        return (
+            isinstance(other, PdfName) and other.name == self.name
+        ) or other == self.name
+
+    def __hash__(self):
+        return hash(self.name)
+
+    def __repr__(self):
+        return f"PdfName({repr(self.name)})"
+
+    @classmethod
+    def from_pdf_stream(cls, data):
+        return cls(PdfParser.interpret_name(data))
+
+    allowed_chars = set(range(33, 127)) - {ord(c) for c in "#%/()<>[]{}"}
+
+    def __bytes__(self):
+        result = bytearray(b"/")
+        for b in self.name:
+            if b in self.allowed_chars:
+                result.append(b)
+            else:
+                result.extend(b"#%02X" % b)
+        return bytes(result)
+
+
+class PdfArray(list):
+    def __bytes__(self):
+        return b"[ " + b" ".join(pdf_repr(x) for x in self) + b" ]"
+
+
+class PdfDict(collections.UserDict):
+    def __setattr__(self, key, value):
+        if key == "data":
+            collections.UserDict.__setattr__(self, key, value)
+        else:
+            self[key.encode("us-ascii")] = value
+
+    def __getattr__(self, key):
+        try:
+            value = self[key.encode("us-ascii")]
+        except KeyError as e:
+            raise AttributeError(key) from e
+        if isinstance(value, bytes):
+            value = decode_text(value)
+        if key.endswith("Date"):
+            if value.startswith("D:"):
+                value = value[2:]
+
+            relationship = "Z"
+            if len(value) > 17:
+                relationship = value[14]
+                offset = int(value[15:17]) * 60
+                if len(value) > 20:
+                    offset += int(value[18:20])
+
+            format = "%Y%m%d%H%M%S"[: len(value) - 2]
+            value = time.strptime(value[: len(format) + 2], format)
+            if relationship in ["+", "-"]:
+                offset *= 60
+                if relationship == "+":
+                    offset *= -1
+                value = time.gmtime(calendar.timegm(value) + offset)
+        return value
+
+    def __bytes__(self):
+        out = bytearray(b"<<")
+        for key, value in self.items():
+            if value is None:
+                continue
+            value = pdf_repr(value)
+            out.extend(b"\n")
+            out.extend(bytes(PdfName(key)))
+            out.extend(b" ")
+            out.extend(value)
+        out.extend(b"\n>>")
+        return bytes(out)
+
+
+class PdfBinary:
+    def __init__(self, data):
+        self.data = data
+
+    def __bytes__(self):
+        return b"<%s>" % b"".join(b"%02X" % b for b in self.data)
+
+
+class PdfStream:
+    def __init__(self, dictionary, buf):
+        self.dictionary = dictionary
+        self.buf = buf
+
+    def decode(self):
+        try:
+            filter = self.dictionary.Filter
+        except AttributeError:
+            return self.buf
+        if filter == b"FlateDecode":
+            try:
+                expected_length = self.dictionary.DL
+            except AttributeError:
+                expected_length = self.dictionary.Length
+            return zlib.decompress(self.buf, bufsize=int(expected_length))
+        else:
+            raise NotImplementedError(
+                f"stream filter {repr(self.dictionary.Filter)} unknown/unsupported"
+            )
+
+
+def pdf_repr(x):
+    if x is True:
+        return b"true"
+    elif x is False:
+        return b"false"
+    elif x is None:
+        return b"null"
+    elif isinstance(x, (PdfName, PdfDict, PdfArray, PdfBinary)):
+        return bytes(x)
+    elif isinstance(x, int):
+        return str(x).encode("us-ascii")
+    elif isinstance(x, float):
+        return str(x).encode("us-ascii")
+    elif isinstance(x, time.struct_time):
+        return b"(D:" + time.strftime("%Y%m%d%H%M%SZ", x).encode("us-ascii") + b")"
+    elif isinstance(x, dict):
+        return bytes(PdfDict(x))
+    elif isinstance(x, list):
+        return bytes(PdfArray(x))
+    elif isinstance(x, str):
+        return pdf_repr(encode_text(x))
+    elif isinstance(x, bytes):
+        # XXX escape more chars? handle binary garbage
+        x = x.replace(b"\\", b"\\\\")
+        x = x.replace(b"(", b"\\(")
+        x = x.replace(b")", b"\\)")
+        return b"(" + x + b")"
+    else:
+        return bytes(x)
+
+
+class PdfParser:
+    """Based on
+    https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/PDF32000_2008.pdf
+    Supports PDF up to 1.4
+    """
+
+    def __init__(self, filename=None, f=None, buf=None, start_offset=0, mode="rb"):
+        if buf and f:
+            raise RuntimeError("specify buf or f or filename, but not both buf and f")
+        self.filename = filename
+        self.buf = buf
+        self.f = f
+        self.start_offset = start_offset
+        self.should_close_buf = False
+        self.should_close_file = False
+        if filename is not None and f is None:
+            self.f = f = open(filename, mode)
+            self.should_close_file = True
+        if f is not None:
+            self.buf = buf = self.get_buf_from_file(f)
+            self.should_close_buf = True
+            if not filename and hasattr(f, "name"):
+                self.filename = f.name
+        self.cached_objects = {}
+        if buf:
+            self.read_pdf_info()
+        else:
+            self.file_size_total = self.file_size_this = 0
+            self.root = PdfDict()
+            self.root_ref = None
+            self.info = PdfDict()
+            self.info_ref = None
+            self.page_tree_root = {}
+            self.pages = []
+            self.orig_pages = []
+            self.pages_ref = None
+            self.last_xref_section_offset = None
+            self.trailer_dict = {}
+            self.xref_table = XrefTable()
+        self.xref_table.reading_finished = True
+        if f:
+            self.seek_end()
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        self.close()
+        return False  # do not suppress exceptions
+
+    def start_writing(self):
+        self.close_buf()
+        self.seek_end()
+
+    def close_buf(self):
+        try:
+            self.buf.close()
+        except AttributeError:
+            pass
+        self.buf = None
+
+    def close(self):
+        if self.should_close_buf:
+            self.close_buf()
+        if self.f is not None and self.should_close_file:
+            self.f.close()
+            self.f = None
+
+    def seek_end(self):
+        self.f.seek(0, os.SEEK_END)
+
+    def write_header(self):
+        self.f.write(b"%PDF-1.4\n")
+
+    def write_comment(self, s):
+        self.f.write(f"% {s}\n".encode())
+
+    def write_catalog(self):
+        self.del_root()
+        self.root_ref = self.next_object_id(self.f.tell())
+        self.pages_ref = self.next_object_id(0)
+        self.rewrite_pages()
+        self.write_obj(self.root_ref, Type=PdfName(b"Catalog"), Pages=self.pages_ref)
+        self.write_obj(
+            self.pages_ref,
+            Type=PdfName(b"Pages"),
+            Count=len(self.pages),
+            Kids=self.pages,
+        )
+        return self.root_ref
+
+    def rewrite_pages(self):
+        pages_tree_nodes_to_delete = []
+        for i, page_ref in enumerate(self.orig_pages):
+            page_info = self.cached_objects[page_ref]
+            del self.xref_table[page_ref.object_id]
+            pages_tree_nodes_to_delete.append(page_info[PdfName(b"Parent")])
+            if page_ref not in self.pages:
+                # the page has been deleted
+                continue
+            # make dict keys into strings for passing to write_page
+            stringified_page_info = {}
+            for key, value in page_info.items():
+                # key should be a PdfName
+                stringified_page_info[key.name_as_str()] = value
+            stringified_page_info["Parent"] = self.pages_ref
+            new_page_ref = self.write_page(None, **stringified_page_info)
+            for j, cur_page_ref in enumerate(self.pages):
+                if cur_page_ref == page_ref:
+                    # replace the page reference with the new one
+                    self.pages[j] = new_page_ref
+        # delete redundant Pages tree nodes from xref table
+        for pages_tree_node_ref in pages_tree_nodes_to_delete:
+            while pages_tree_node_ref:
+                pages_tree_node = self.cached_objects[pages_tree_node_ref]
+                if pages_tree_node_ref.object_id in self.xref_table:
+                    del self.xref_table[pages_tree_node_ref.object_id]
+                pages_tree_node_ref = pages_tree_node.get(b"Parent", None)
+        self.orig_pages = []
+
+    def write_xref_and_trailer(self, new_root_ref=None):
+        if new_root_ref:
+            self.del_root()
+            self.root_ref = new_root_ref
+        if self.info:
+            self.info_ref = self.write_obj(None, self.info)
+        start_xref = self.xref_table.write(self.f)
+        num_entries = len(self.xref_table)
+        trailer_dict = {b"Root": self.root_ref, b"Size": num_entries}
+        if self.last_xref_section_offset is not None:
+            trailer_dict[b"Prev"] = self.last_xref_section_offset
+        if self.info:
+            trailer_dict[b"Info"] = self.info_ref
+        self.last_xref_section_offset = start_xref
+        self.f.write(
+            b"trailer\n"
+            + bytes(PdfDict(trailer_dict))
+            + b"\nstartxref\n%d\n%%%%EOF" % start_xref
+        )
+
+    def write_page(self, ref, *objs, **dict_obj):
+        if isinstance(ref, int):
+            ref = self.pages[ref]
+        if "Type" not in dict_obj:
+            dict_obj["Type"] = PdfName(b"Page")
+        if "Parent" not in dict_obj:
+            dict_obj["Parent"] = self.pages_ref
+        return self.write_obj(ref, *objs, **dict_obj)
+
+    def write_obj(self, ref, *objs, **dict_obj):
+        f = self.f
+        if ref is None:
+            ref = self.next_object_id(f.tell())
+        else:
+            self.xref_table[ref.object_id] = (f.tell(), ref.generation)
+        f.write(bytes(IndirectObjectDef(*ref)))
+        stream = dict_obj.pop("stream", None)
+        if stream is not None:
+            dict_obj["Length"] = len(stream)
+        if dict_obj:
+            f.write(pdf_repr(dict_obj))
+        for obj in objs:
+            f.write(pdf_repr(obj))
+        if stream is not None:
+            f.write(b"stream\n")
+            f.write(stream)
+            f.write(b"\nendstream\n")
+        f.write(b"endobj\n")
+        return ref
+
+    def del_root(self):
+        if self.root_ref is None:
+            return
+        del self.xref_table[self.root_ref.object_id]
+        del self.xref_table[self.root[b"Pages"].object_id]
+
+    @staticmethod
+    def get_buf_from_file(f):
+        if hasattr(f, "getbuffer"):
+            return f.getbuffer()
+        elif hasattr(f, "getvalue"):
+            return f.getvalue()
+        else:
+            try:
+                return mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ)
+            except ValueError:  # cannot mmap an empty file
+                return b""
+
+    def read_pdf_info(self):
+        self.file_size_total = len(self.buf)
+        self.file_size_this = self.file_size_total - self.start_offset
+        self.read_trailer()
+        self.root_ref = self.trailer_dict[b"Root"]
+        self.info_ref = self.trailer_dict.get(b"Info", None)
+        self.root = PdfDict(self.read_indirect(self.root_ref))
+        if self.info_ref is None:
+            self.info = PdfDict()
+        else:
+            self.info = PdfDict(self.read_indirect(self.info_ref))
+        check_format_condition(b"Type" in self.root, "/Type missing in Root")
+        check_format_condition(
+            self.root[b"Type"] == b"Catalog", "/Type in Root is not /Catalog"
+        )
+        check_format_condition(b"Pages" in self.root, "/Pages missing in Root")
+        check_format_condition(
+            isinstance(self.root[b"Pages"], IndirectReference),
+            "/Pages in Root is not an indirect reference",
+        )
+        self.pages_ref = self.root[b"Pages"]
+        self.page_tree_root = self.read_indirect(self.pages_ref)
+        self.pages = self.linearize_page_tree(self.page_tree_root)
+        # save the original list of page references
+        # in case the user modifies, adds or deletes some pages
+        # and we need to rewrite the pages and their list
+        self.orig_pages = self.pages[:]
+
+    def next_object_id(self, offset=None):
+        try:
+            # TODO: support reuse of deleted objects
+            reference = IndirectReference(max(self.xref_table.keys()) + 1, 0)
+        except ValueError:
+            reference = IndirectReference(1, 0)
+        if offset is not None:
+            self.xref_table[reference.object_id] = (offset, 0)
+        return reference
+
+    delimiter = rb"[][()<>{}/%]"
+    delimiter_or_ws = rb"[][()<>{}/%\000\011\012\014\015\040]"
+    whitespace = rb"[\000\011\012\014\015\040]"
+    whitespace_or_hex = rb"[\000\011\012\014\015\0400-9a-fA-F]"
+    whitespace_optional = whitespace + b"*"
+    whitespace_mandatory = whitespace + b"+"
+    # No "\012" aka "\n" or "\015" aka "\r":
+    whitespace_optional_no_nl = rb"[\000\011\014\040]*"
+    newline_only = rb"[\r\n]+"
+    newline = whitespace_optional_no_nl + newline_only + whitespace_optional_no_nl
+    re_trailer_end = re.compile(
+        whitespace_mandatory
+        + rb"trailer"
+        + whitespace_optional
+        + rb"<<(.*>>)"
+        + newline
+        + rb"startxref"
+        + newline
+        + rb"([0-9]+)"
+        + newline
+        + rb"%%EOF"
+        + whitespace_optional
+        + rb"$",
+        re.DOTALL,
+    )
+    re_trailer_prev = re.compile(
+        whitespace_optional
+        + rb"trailer"
+        + whitespace_optional
+        + rb"<<(.*?>>)"
+        + newline
+        + rb"startxref"
+        + newline
+        + rb"([0-9]+)"
+        + newline
+        + rb"%%EOF"
+        + whitespace_optional,
+        re.DOTALL,
+    )
+
+    def read_trailer(self):
+        search_start_offset = len(self.buf) - 16384
+        if search_start_offset < self.start_offset:
+            search_start_offset = self.start_offset
+        m = self.re_trailer_end.search(self.buf, search_start_offset)
+        check_format_condition(m, "trailer end not found")
+        # make sure we found the LAST trailer
+        last_match = m
+        while m:
+            last_match = m
+            m = self.re_trailer_end.search(self.buf, m.start() + 16)
+        if not m:
+            m = last_match
+        trailer_data = m.group(1)
+        self.last_xref_section_offset = int(m.group(2))
+        self.trailer_dict = self.interpret_trailer(trailer_data)
+        self.xref_table = XrefTable()
+        self.read_xref_table(xref_section_offset=self.last_xref_section_offset)
+        if b"Prev" in self.trailer_dict:
+            self.read_prev_trailer(self.trailer_dict[b"Prev"])
+
+    def read_prev_trailer(self, xref_section_offset):
+        trailer_offset = self.read_xref_table(xref_section_offset=xref_section_offset)
+        m = self.re_trailer_prev.search(
+            self.buf[trailer_offset : trailer_offset + 16384]
+        )
+        check_format_condition(m, "previous trailer not found")
+        trailer_data = m.group(1)
+        check_format_condition(
+            int(m.group(2)) == xref_section_offset,
+            "xref section offset in previous trailer doesn't match what was expected",
+        )
+        trailer_dict = self.interpret_trailer(trailer_data)
+        if b"Prev" in trailer_dict:
+            self.read_prev_trailer(trailer_dict[b"Prev"])
+
+    re_whitespace_optional = re.compile(whitespace_optional)
+    re_name = re.compile(
+        whitespace_optional
+        + rb"/([!-$&'*-.0-;=?-Z\\^-z|~]+)(?="
+        + delimiter_or_ws
+        + rb")"
+    )
+    re_dict_start = re.compile(whitespace_optional + rb"<<")
+    re_dict_end = re.compile(whitespace_optional + rb">>" + whitespace_optional)
+
+    @classmethod
+    def interpret_trailer(cls, trailer_data):
+        trailer = {}
+        offset = 0
+        while True:
+            m = cls.re_name.match(trailer_data, offset)
+            if not m:
+                m = cls.re_dict_end.match(trailer_data, offset)
+                check_format_condition(
+                    m and m.end() == len(trailer_data),
+                    "name not found in trailer, remaining data: "
+                    + repr(trailer_data[offset:]),
+                )
+                break
+            key = cls.interpret_name(m.group(1))
+            value, offset = cls.get_value(trailer_data, m.end())
+            trailer[key] = value
+        check_format_condition(
+            b"Size" in trailer and isinstance(trailer[b"Size"], int),
+            "/Size not in trailer or not an integer",
+        )
+        check_format_condition(
+            b"Root" in trailer and isinstance(trailer[b"Root"], IndirectReference),
+            "/Root not in trailer or not an indirect reference",
+        )
+        return trailer
+
+    re_hashes_in_name = re.compile(rb"([^#]*)(#([0-9a-fA-F]{2}))?")
+
+    @classmethod
+    def interpret_name(cls, raw, as_text=False):
+        name = b""
+        for m in cls.re_hashes_in_name.finditer(raw):
+            if m.group(3):
+                name += m.group(1) + bytearray.fromhex(m.group(3).decode("us-ascii"))
+            else:
+                name += m.group(1)
+        if as_text:
+            return name.decode("utf-8")
+        else:
+            return bytes(name)
+
+    re_null = re.compile(whitespace_optional + rb"null(?=" + delimiter_or_ws + rb")")
+    re_true = re.compile(whitespace_optional + rb"true(?=" + delimiter_or_ws + rb")")
+    re_false = re.compile(whitespace_optional + rb"false(?=" + delimiter_or_ws + rb")")
+    re_int = re.compile(
+        whitespace_optional + rb"([-+]?[0-9]+)(?=" + delimiter_or_ws + rb")"
+    )
+    re_real = re.compile(
+        whitespace_optional
+        + rb"([-+]?([0-9]+\.[0-9]*|[0-9]*\.[0-9]+))(?="
+        + delimiter_or_ws
+        + rb")"
+    )
+    re_array_start = re.compile(whitespace_optional + rb"\[")
+    re_array_end = re.compile(whitespace_optional + rb"]")
+    re_string_hex = re.compile(
+        whitespace_optional + rb"<(" + whitespace_or_hex + rb"*)>"
+    )
+    re_string_lit = re.compile(whitespace_optional + rb"\(")
+    re_indirect_reference = re.compile(
+        whitespace_optional
+        + rb"([-+]?[0-9]+)"
+        + whitespace_mandatory
+        + rb"([-+]?[0-9]+)"
+        + whitespace_mandatory
+        + rb"R(?="
+        + delimiter_or_ws
+        + rb")"
+    )
+    re_indirect_def_start = re.compile(
+        whitespace_optional
+        + rb"([-+]?[0-9]+)"
+        + whitespace_mandatory
+        + rb"([-+]?[0-9]+)"
+        + whitespace_mandatory
+        + rb"obj(?="
+        + delimiter_or_ws
+        + rb")"
+    )
+    re_indirect_def_end = re.compile(
+        whitespace_optional + rb"endobj(?=" + delimiter_or_ws + rb")"
+    )
+    re_comment = re.compile(
+        rb"(" + whitespace_optional + rb"%[^\r\n]*" + newline + rb")*"
+    )
+    re_stream_start = re.compile(whitespace_optional + rb"stream\r?\n")
+    re_stream_end = re.compile(
+        whitespace_optional + rb"endstream(?=" + delimiter_or_ws + rb")"
+    )
+
+    @classmethod
+    def get_value(cls, data, offset, expect_indirect=None, max_nesting=-1):
+        if max_nesting == 0:
+            return None, None
+        m = cls.re_comment.match(data, offset)
+        if m:
+            offset = m.end()
+        m = cls.re_indirect_def_start.match(data, offset)
+        if m:
+            check_format_condition(
+                int(m.group(1)) > 0,
+                "indirect object definition: object ID must be greater than 0",
+            )
+            check_format_condition(
+                int(m.group(2)) >= 0,
+                "indirect object definition: generation must be non-negative",
+            )
+            check_format_condition(
+                expect_indirect is None
+                or expect_indirect
+                == IndirectReference(int(m.group(1)), int(m.group(2))),
+                "indirect object definition different than expected",
+            )
+            object, offset = cls.get_value(data, m.end(), max_nesting=max_nesting - 1)
+            if offset is None:
+                return object, None
+            m = cls.re_indirect_def_end.match(data, offset)
+            check_format_condition(m, "indirect object definition end not found")
+            return object, m.end()
+        check_format_condition(
+            not expect_indirect, "indirect object definition not found"
+        )
+        m = cls.re_indirect_reference.match(data, offset)
+        if m:
+            check_format_condition(
+                int(m.group(1)) > 0,
+                "indirect object reference: object ID must be greater than 0",
+            )
+            check_format_condition(
+                int(m.group(2)) >= 0,
+                "indirect object reference: generation must be non-negative",
+            )
+            return IndirectReference(int(m.group(1)), int(m.group(2))), m.end()
+        m = cls.re_dict_start.match(data, offset)
+        if m:
+            offset = m.end()
+            result = {}
+            m = cls.re_dict_end.match(data, offset)
+            while not m:
+                key, offset = cls.get_value(data, offset, max_nesting=max_nesting - 1)
+                if offset is None:
+                    return result, None
+                value, offset = cls.get_value(data, offset, max_nesting=max_nesting - 1)
+                result[key] = value
+                if offset is None:
+                    return result, None
+                m = cls.re_dict_end.match(data, offset)
+            offset = m.end()
+            m = cls.re_stream_start.match(data, offset)
+            if m:
+                try:
+                    stream_len = int(result[b"Length"])
+                except (TypeError, KeyError, ValueError) as e:
+                    raise PdfFormatError(
+                        "bad or missing Length in stream dict (%r)"
+                        % result.get(b"Length", None)
+                    ) from e
+                stream_data = data[m.end() : m.end() + stream_len]
+                m = cls.re_stream_end.match(data, m.end() + stream_len)
+                check_format_condition(m, "stream end not found")
+                offset = m.end()
+                result = PdfStream(PdfDict(result), stream_data)
+            else:
+                result = PdfDict(result)
+            return result, offset
+        m = cls.re_array_start.match(data, offset)
+        if m:
+            offset = m.end()
+            result = []
+            m = cls.re_array_end.match(data, offset)
+            while not m:
+                value, offset = cls.get_value(data, offset, max_nesting=max_nesting - 1)
+                result.append(value)
+                if offset is None:
+                    return result, None
+                m = cls.re_array_end.match(data, offset)
+            return result, m.end()
+        m = cls.re_null.match(data, offset)
+        if m:
+            return None, m.end()
+        m = cls.re_true.match(data, offset)
+        if m:
+            return True, m.end()
+        m = cls.re_false.match(data, offset)
+        if m:
+            return False, m.end()
+        m = cls.re_name.match(data, offset)
+        if m:
+            return PdfName(cls.interpret_name(m.group(1))), m.end()
+        m = cls.re_int.match(data, offset)
+        if m:
+            return int(m.group(1)), m.end()
+        m = cls.re_real.match(data, offset)
+        if m:
+            # XXX Decimal instead of float???
+            return float(m.group(1)), m.end()
+        m = cls.re_string_hex.match(data, offset)
+        if m:
+            # filter out whitespace
+            hex_string = bytearray(
+                b for b in m.group(1) if b in b"0123456789abcdefABCDEF"
+            )
+            if len(hex_string) % 2 == 1:
+                # append a 0 if the length is not even - yes, at the end
+                hex_string.append(ord(b"0"))
+            return bytearray.fromhex(hex_string.decode("us-ascii")), m.end()
+        m = cls.re_string_lit.match(data, offset)
+        if m:
+            return cls.get_literal_string(data, m.end())
+        # return None, offset  # fallback (only for debugging)
+        raise PdfFormatError("unrecognized object: " + repr(data[offset : offset + 32]))
+
+    re_lit_str_token = re.compile(
+        rb"(\\[nrtbf()\\])|(\\[0-9]{1,3})|(\\(\r\n|\r|\n))|(\r\n|\r|\n)|(\()|(\))"
+    )
+    escaped_chars = {
+        b"n": b"\n",
+        b"r": b"\r",
+        b"t": b"\t",
+        b"b": b"\b",
+        b"f": b"\f",
+        b"(": b"(",
+        b")": b")",
+        b"\\": b"\\",
+        ord(b"n"): b"\n",
+        ord(b"r"): b"\r",
+        ord(b"t"): b"\t",
+        ord(b"b"): b"\b",
+        ord(b"f"): b"\f",
+        ord(b"("): b"(",
+        ord(b")"): b")",
+        ord(b"\\"): b"\\",
+    }
+
+    @classmethod
+    def get_literal_string(cls, data, offset):
+        nesting_depth = 0
+        result = bytearray()
+        for m in cls.re_lit_str_token.finditer(data, offset):
+            result.extend(data[offset : m.start()])
+            if m.group(1):
+                result.extend(cls.escaped_chars[m.group(1)[1]])
+            elif m.group(2):
+                result.append(int(m.group(2)[1:], 8))
+            elif m.group(3):
+                pass
+            elif m.group(5):
+                result.extend(b"\n")
+            elif m.group(6):
+                result.extend(b"(")
+                nesting_depth += 1
+            elif m.group(7):
+                if nesting_depth == 0:
+                    return bytes(result), m.end()
+                result.extend(b")")
+                nesting_depth -= 1
+            offset = m.end()
+        raise PdfFormatError("unfinished literal string")
+
+    re_xref_section_start = re.compile(whitespace_optional + rb"xref" + newline)
+    re_xref_subsection_start = re.compile(
+        whitespace_optional
+        + rb"([0-9]+)"
+        + whitespace_mandatory
+        + rb"([0-9]+)"
+        + whitespace_optional
+        + newline_only
+    )
+    re_xref_entry = re.compile(rb"([0-9]{10}) ([0-9]{5}) ([fn])( \r| \n|\r\n)")
+
+    def read_xref_table(self, xref_section_offset):
+        subsection_found = False
+        m = self.re_xref_section_start.match(
+            self.buf, xref_section_offset + self.start_offset
+        )
+        check_format_condition(m, "xref section start not found")
+        offset = m.end()
+        while True:
+            m = self.re_xref_subsection_start.match(self.buf, offset)
+            if not m:
+                check_format_condition(
+                    subsection_found, "xref subsection start not found"
+                )
+                break
+            subsection_found = True
+            offset = m.end()
+            first_object = int(m.group(1))
+            num_objects = int(m.group(2))
+            for i in range(first_object, first_object + num_objects):
+                m = self.re_xref_entry.match(self.buf, offset)
+                check_format_condition(m, "xref entry not found")
+                offset = m.end()
+                is_free = m.group(3) == b"f"
+                generation = int(m.group(2))
+                if not is_free:
+                    new_entry = (int(m.group(1)), generation)
+                    check_format_condition(
+                        i not in self.xref_table or self.xref_table[i] == new_entry,
+                        "xref entry duplicated (and not identical)",
+                    )
+                    self.xref_table[i] = new_entry
+        return offset
+
+    def read_indirect(self, ref, max_nesting=-1):
+        offset, generation = self.xref_table[ref[0]]
+        check_format_condition(
+            generation == ref[1],
+            f"expected to find generation {ref[1]} for object ID {ref[0]} in xref "
+            f"table, instead found generation {generation} at offset {offset}",
+        )
+        value = self.get_value(
+            self.buf,
+            offset + self.start_offset,
+            expect_indirect=IndirectReference(*ref),
+            max_nesting=max_nesting,
+        )[0]
+        self.cached_objects[ref] = value
+        return value
+
+    def linearize_page_tree(self, node=None):
+        if node is None:
+            node = self.page_tree_root
+        check_format_condition(
+            node[b"Type"] == b"Pages", "/Type of page tree node is not /Pages"
+        )
+        pages = []
+        for kid in node[b"Kids"]:
+            kid_object = self.read_indirect(kid)
+            if kid_object[b"Type"] == b"Page":
+                pages.append(kid)
+            else:
+                pages.extend(self.linearize_page_tree(node=kid_object))
+        return pages