Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/PIL/PdfParser.py: 19%
Shortcuts on this page
r m x toggle line displays
j k next/prev highlighted chunk
0 (zero) top of page
1 (one) first highlighted chunk
1from __future__ import annotations
3import calendar
4import codecs
5import collections
6import mmap
7import os
8import re
9import time
10import zlib
11from typing import Any, NamedTuple
13TYPE_CHECKING = False
14if TYPE_CHECKING:
15 from typing import IO
17 _DictBase = collections.UserDict[str | bytes, Any]
18else:
19 _DictBase = collections.UserDict
22# see 7.9.2.2 Text String Type on page 86 and D.3 PDFDocEncoding Character Set
23# on page 656
24def encode_text(s: str) -> bytes:
25 return codecs.BOM_UTF16_BE + s.encode("utf_16_be")
28PDFDocEncoding = {
29 0x16: "\u0017",
30 0x18: "\u02d8",
31 0x19: "\u02c7",
32 0x1A: "\u02c6",
33 0x1B: "\u02d9",
34 0x1C: "\u02dd",
35 0x1D: "\u02db",
36 0x1E: "\u02da",
37 0x1F: "\u02dc",
38 0x80: "\u2022",
39 0x81: "\u2020",
40 0x82: "\u2021",
41 0x83: "\u2026",
42 0x84: "\u2014",
43 0x85: "\u2013",
44 0x86: "\u0192",
45 0x87: "\u2044",
46 0x88: "\u2039",
47 0x89: "\u203a",
48 0x8A: "\u2212",
49 0x8B: "\u2030",
50 0x8C: "\u201e",
51 0x8D: "\u201c",
52 0x8E: "\u201d",
53 0x8F: "\u2018",
54 0x90: "\u2019",
55 0x91: "\u201a",
56 0x92: "\u2122",
57 0x93: "\ufb01",
58 0x94: "\ufb02",
59 0x95: "\u0141",
60 0x96: "\u0152",
61 0x97: "\u0160",
62 0x98: "\u0178",
63 0x99: "\u017d",
64 0x9A: "\u0131",
65 0x9B: "\u0142",
66 0x9C: "\u0153",
67 0x9D: "\u0161",
68 0x9E: "\u017e",
69 0xA0: "\u20ac",
70}
73def decode_text(b: bytes) -> str:
74 if b[: len(codecs.BOM_UTF16_BE)] == codecs.BOM_UTF16_BE:
75 return b[len(codecs.BOM_UTF16_BE) :].decode("utf_16_be")
76 else:
77 return "".join(PDFDocEncoding.get(byte, chr(byte)) for byte in b)
80class PdfFormatError(RuntimeError):
81 """An error that probably indicates a syntactic or semantic error in the
82 PDF file structure"""
84 pass
87def check_format_condition(condition: bool, error_message: str) -> None:
88 if not condition:
89 raise PdfFormatError(error_message)
92class IndirectReferenceTuple(NamedTuple):
93 object_id: int
94 generation: int
97class IndirectReference(IndirectReferenceTuple):
98 def __str__(self) -> str:
99 return f"{self.object_id} {self.generation} R"
101 def __bytes__(self) -> bytes:
102 return self.__str__().encode("us-ascii")
104 def __eq__(self, other: object) -> bool:
105 if self.__class__ is not other.__class__:
106 return False
107 assert isinstance(other, IndirectReference)
108 return other.object_id == self.object_id and other.generation == self.generation
110 def __ne__(self, other: object) -> bool:
111 return not (self == other)
113 def __hash__(self) -> int:
114 return hash((self.object_id, self.generation))
117class IndirectObjectDef(IndirectReference):
118 def __str__(self) -> str:
119 return f"{self.object_id} {self.generation} obj"
122class XrefTable:
123 def __init__(self) -> None:
124 self.existing_entries: dict[int, tuple[int, int]] = (
125 {}
126 ) # object ID => (offset, generation)
127 self.new_entries: dict[int, tuple[int, int]] = (
128 {}
129 ) # object ID => (offset, generation)
130 self.deleted_entries = {0: 65536} # object ID => generation
131 self.reading_finished = False
133 def __setitem__(self, key: int, value: tuple[int, int]) -> None:
134 if self.reading_finished:
135 self.new_entries[key] = value
136 else:
137 self.existing_entries[key] = value
138 if key in self.deleted_entries:
139 del self.deleted_entries[key]
141 def __getitem__(self, key: int) -> tuple[int, int]:
142 try:
143 return self.new_entries[key]
144 except KeyError:
145 return self.existing_entries[key]
147 def __delitem__(self, key: int) -> None:
148 if key in self.new_entries:
149 generation = self.new_entries[key][1] + 1
150 del self.new_entries[key]
151 self.deleted_entries[key] = generation
152 elif key in self.existing_entries:
153 generation = self.existing_entries[key][1] + 1
154 self.deleted_entries[key] = generation
155 elif key in self.deleted_entries:
156 generation = self.deleted_entries[key]
157 else:
158 msg = f"object ID {key} cannot be deleted because it doesn't exist"
159 raise IndexError(msg)
161 def __contains__(self, key: int) -> bool:
162 return key in self.existing_entries or key in self.new_entries
164 def __len__(self) -> int:
165 return len(
166 set(self.existing_entries.keys())
167 | set(self.new_entries.keys())
168 | set(self.deleted_entries.keys())
169 )
171 def keys(self) -> set[int]:
172 return (
173 set(self.existing_entries.keys()) - set(self.deleted_entries.keys())
174 ) | set(self.new_entries.keys())
176 def write(self, f: IO[bytes]) -> int:
177 keys = sorted(set(self.new_entries.keys()) | set(self.deleted_entries.keys()))
178 deleted_keys = sorted(set(self.deleted_entries.keys()))
179 startxref = f.tell()
180 f.write(b"xref\n")
181 while keys:
182 # find a contiguous sequence of object IDs
183 prev: int | None = None
184 for index, key in enumerate(keys):
185 if prev is None or prev + 1 == key:
186 prev = key
187 else:
188 contiguous_keys = keys[:index]
189 keys = keys[index:]
190 break
191 else:
192 contiguous_keys = keys
193 keys = []
194 f.write(b"%d %d\n" % (contiguous_keys[0], len(contiguous_keys)))
195 for object_id in contiguous_keys:
196 if object_id in self.new_entries:
197 f.write(b"%010d %05d n \n" % self.new_entries[object_id])
198 else:
199 this_deleted_object_id = deleted_keys.pop(0)
200 check_format_condition(
201 object_id == this_deleted_object_id,
202 f"expected the next deleted object ID to be {object_id}, "
203 f"instead found {this_deleted_object_id}",
204 )
205 try:
206 next_in_linked_list = deleted_keys[0]
207 except IndexError:
208 next_in_linked_list = 0
209 f.write(
210 b"%010d %05d f \n"
211 % (next_in_linked_list, self.deleted_entries[object_id])
212 )
213 return startxref
216class PdfName:
217 name: bytes
219 def __init__(self, name: PdfName | bytes | str) -> None:
220 if isinstance(name, PdfName):
221 self.name = name.name
222 elif isinstance(name, bytes):
223 self.name = name
224 else:
225 self.name = name.encode("us-ascii")
227 def name_as_str(self) -> str:
228 return self.name.decode("us-ascii")
230 def __eq__(self, other: object) -> bool:
231 return (
232 isinstance(other, PdfName) and other.name == self.name
233 ) or other == self.name
235 def __hash__(self) -> int:
236 return hash(self.name)
238 def __repr__(self) -> str:
239 return f"{self.__class__.__name__}({repr(self.name)})"
241 @classmethod
242 def from_pdf_stream(cls, data: bytes) -> PdfName:
243 return cls(PdfParser.interpret_name(data))
245 allowed_chars = set(range(33, 127)) - {ord(c) for c in "#%/()<>[]{}"}
247 def __bytes__(self) -> bytes:
248 result = bytearray(b"/")
249 for b in self.name:
250 if b in self.allowed_chars:
251 result.append(b)
252 else:
253 result.extend(b"#%02X" % b)
254 return bytes(result)
257class PdfArray(list[Any]):
258 def __bytes__(self) -> bytes:
259 return b"[ " + b" ".join(pdf_repr(x) for x in self) + b" ]"
262class PdfDict(_DictBase):
263 def __setattr__(self, key: str, value: Any) -> None:
264 if key == "data":
265 collections.UserDict.__setattr__(self, key, value)
266 else:
267 self[key.encode("us-ascii")] = value
269 def __getattr__(self, key: str) -> str | time.struct_time:
270 try:
271 value = self[key.encode("us-ascii")]
272 except KeyError as e:
273 raise AttributeError(key) from e
274 if isinstance(value, bytes):
275 value = decode_text(value)
276 if key.endswith("Date"):
277 if value.startswith("D:"):
278 value = value[2:]
280 relationship = "Z"
281 if len(value) > 17:
282 relationship = value[14]
283 offset = int(value[15:17]) * 60
284 if len(value) > 20:
285 offset += int(value[18:20])
287 format = "%Y%m%d%H%M%S"[: len(value) - 2]
288 value = time.strptime(value[: len(format) + 2], format)
289 if relationship in ["+", "-"]:
290 offset *= 60
291 if relationship == "+":
292 offset *= -1
293 value = time.gmtime(calendar.timegm(value) + offset)
294 return value
296 def __bytes__(self) -> bytes:
297 out = bytearray(b"<<")
298 for key, value in self.items():
299 if value is None:
300 continue
301 value = pdf_repr(value)
302 out.extend(b"\n")
303 out.extend(bytes(PdfName(key)))
304 out.extend(b" ")
305 out.extend(value)
306 out.extend(b"\n>>")
307 return bytes(out)
310class PdfBinary:
311 def __init__(self, data: list[int] | bytes) -> None:
312 self.data = data
314 def __bytes__(self) -> bytes:
315 return b"<%s>" % b"".join(b"%02X" % b for b in self.data)
318class PdfStream:
319 def __init__(self, dictionary: PdfDict, buf: bytes) -> None:
320 self.dictionary = dictionary
321 self.buf = buf
323 def decode(self) -> bytes:
324 try:
325 filter = self.dictionary[b"Filter"]
326 except KeyError:
327 return self.buf
328 if filter == b"FlateDecode":
329 try:
330 expected_length = self.dictionary[b"DL"]
331 except KeyError:
332 expected_length = self.dictionary[b"Length"]
333 return zlib.decompress(self.buf, bufsize=int(expected_length))
334 else:
335 msg = f"stream filter {repr(filter)} unknown/unsupported"
336 raise NotImplementedError(msg)
339def pdf_repr(x: Any) -> bytes:
340 if x is True:
341 return b"true"
342 elif x is False:
343 return b"false"
344 elif x is None:
345 return b"null"
346 elif isinstance(x, (PdfName, PdfDict, PdfArray, PdfBinary)):
347 return bytes(x)
348 elif isinstance(x, (int, float)):
349 return str(x).encode("us-ascii")
350 elif isinstance(x, time.struct_time):
351 return b"(D:" + time.strftime("%Y%m%d%H%M%SZ", x).encode("us-ascii") + b")"
352 elif isinstance(x, dict):
353 return bytes(PdfDict(x))
354 elif isinstance(x, list):
355 return bytes(PdfArray(x))
356 elif isinstance(x, str):
357 return pdf_repr(encode_text(x))
358 elif isinstance(x, bytes):
359 # XXX escape more chars? handle binary garbage
360 x = x.replace(b"\\", b"\\\\")
361 x = x.replace(b"(", b"\\(")
362 x = x.replace(b")", b"\\)")
363 return b"(" + x + b")"
364 else:
365 return bytes(x)
368class PdfParser:
369 """Based on
370 https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/PDF32000_2008.pdf
371 Supports PDF up to 1.4
372 """
374 def __init__(
375 self,
376 filename: str | None = None,
377 f: IO[bytes] | None = None,
378 buf: bytes | bytearray | None = None,
379 start_offset: int = 0,
380 mode: str = "rb",
381 ) -> None:
382 if buf and f:
383 msg = "specify buf or f or filename, but not both buf and f"
384 raise RuntimeError(msg)
385 self.filename = filename
386 self.buf: bytes | bytearray | memoryview | mmap.mmap | None = buf
387 self.f = f
388 self.start_offset = start_offset
389 self.should_close_buf = False
390 self.should_close_file = False
391 if filename is not None and f is None:
392 self.f = f = open(filename, mode)
393 self.should_close_file = True
394 if f is not None:
395 self.buf = self.get_buf_from_file(f)
396 self.should_close_buf = True
397 if not filename and hasattr(f, "name"):
398 self.filename = f.name
399 self.cached_objects: dict[IndirectReference, Any] = {}
400 self.root_ref: IndirectReference | None
401 self.info_ref: IndirectReference | None
402 self.pages_ref: IndirectReference | None
403 self.last_xref_section_offset: int | None
404 if self.buf:
405 try:
406 self.read_pdf_info()
407 except PdfFormatError:
408 self.close()
409 raise
410 else:
411 self.file_size_total = self.file_size_this = 0
412 self.root = PdfDict()
413 self.root_ref = None
414 self.info = PdfDict()
415 self.info_ref = None
416 self.page_tree_root = PdfDict()
417 self.pages: list[IndirectReference] = []
418 self.orig_pages: list[IndirectReference] = []
419 self.pages_ref = None
420 self.last_xref_section_offset = None
421 self.trailer_dict: dict[bytes, Any] = {}
422 self.xref_table = XrefTable()
423 self.xref_table.reading_finished = True
424 if f:
425 self.seek_end()
427 def __enter__(self) -> PdfParser:
428 return self
430 def __exit__(self, *args: object) -> None:
431 self.close()
433 def start_writing(self) -> None:
434 self.close_buf()
435 self.seek_end()
437 def close_buf(self) -> None:
438 if isinstance(self.buf, memoryview):
439 self.buf.release()
440 elif isinstance(self.buf, mmap.mmap):
441 self.buf.close()
442 self.buf = None
444 def close(self) -> None:
445 if self.should_close_buf:
446 self.close_buf()
447 if self.f is not None and self.should_close_file:
448 self.f.close()
449 self.f = None
451 def seek_end(self) -> None:
452 assert self.f is not None
453 self.f.seek(0, os.SEEK_END)
455 def write_header(self) -> None:
456 assert self.f is not None
457 self.f.write(b"%PDF-1.4\n")
459 def write_comment(self, s: str) -> None:
460 assert self.f is not None
461 self.f.write(f"% {s}\n".encode())
463 def write_catalog(self) -> IndirectReference:
464 assert self.f is not None
465 self.del_root()
466 self.root_ref = self.next_object_id(self.f.tell())
467 self.pages_ref = self.next_object_id(0)
468 self.rewrite_pages()
469 self.write_obj(self.root_ref, Type=PdfName(b"Catalog"), Pages=self.pages_ref)
470 self.write_obj(
471 self.pages_ref,
472 Type=PdfName(b"Pages"),
473 Count=len(self.pages),
474 Kids=self.pages,
475 )
476 return self.root_ref
478 def rewrite_pages(self) -> None:
479 pages_tree_nodes_to_delete = []
480 for i, page_ref in enumerate(self.orig_pages):
481 page_info = self.cached_objects[page_ref]
482 del self.xref_table[page_ref.object_id]
483 pages_tree_nodes_to_delete.append(page_info[PdfName(b"Parent")])
484 if page_ref not in self.pages:
485 # the page has been deleted
486 continue
487 # make dict keys into strings for passing to write_page
488 stringified_page_info = {}
489 for key, value in page_info.items():
490 # key should be a PdfName
491 stringified_page_info[key.name_as_str()] = value
492 stringified_page_info["Parent"] = self.pages_ref
493 new_page_ref = self.write_page(None, **stringified_page_info)
494 for j, cur_page_ref in enumerate(self.pages):
495 if cur_page_ref == page_ref:
496 # replace the page reference with the new one
497 self.pages[j] = new_page_ref
498 # delete redundant Pages tree nodes from xref table
499 for pages_tree_node_ref in pages_tree_nodes_to_delete:
500 while pages_tree_node_ref:
501 pages_tree_node = self.cached_objects[pages_tree_node_ref]
502 if pages_tree_node_ref.object_id in self.xref_table:
503 del self.xref_table[pages_tree_node_ref.object_id]
504 pages_tree_node_ref = pages_tree_node.get(b"Parent", None)
505 self.orig_pages = []
507 def write_xref_and_trailer(
508 self, new_root_ref: IndirectReference | None = None
509 ) -> None:
510 assert self.f is not None
511 if new_root_ref:
512 self.del_root()
513 self.root_ref = new_root_ref
514 if self.info:
515 self.info_ref = self.write_obj(None, self.info)
516 start_xref = self.xref_table.write(self.f)
517 num_entries = len(self.xref_table)
518 trailer_dict: dict[str | bytes, Any] = {
519 b"Root": self.root_ref,
520 b"Size": num_entries,
521 }
522 if self.last_xref_section_offset is not None:
523 trailer_dict[b"Prev"] = self.last_xref_section_offset
524 if self.info:
525 trailer_dict[b"Info"] = self.info_ref
526 self.last_xref_section_offset = start_xref
527 self.f.write(
528 b"trailer\n"
529 + bytes(PdfDict(trailer_dict))
530 + b"\nstartxref\n%d\n%%%%EOF" % start_xref
531 )
533 def write_page(
534 self, ref: int | IndirectReference | None, *objs: Any, **dict_obj: Any
535 ) -> IndirectReference:
536 obj_ref = self.pages[ref] if isinstance(ref, int) else ref
537 if "Type" not in dict_obj:
538 dict_obj["Type"] = PdfName(b"Page")
539 if "Parent" not in dict_obj:
540 dict_obj["Parent"] = self.pages_ref
541 return self.write_obj(obj_ref, *objs, **dict_obj)
543 def write_obj(
544 self, ref: IndirectReference | None, *objs: Any, **dict_obj: Any
545 ) -> IndirectReference:
546 assert self.f is not None
547 f = self.f
548 if ref is None:
549 ref = self.next_object_id(f.tell())
550 else:
551 self.xref_table[ref.object_id] = (f.tell(), ref.generation)
552 f.write(bytes(IndirectObjectDef(*ref)))
553 stream = dict_obj.pop("stream", None)
554 if stream is not None:
555 dict_obj["Length"] = len(stream)
556 if dict_obj:
557 f.write(pdf_repr(dict_obj))
558 for obj in objs:
559 f.write(pdf_repr(obj))
560 if stream is not None:
561 f.write(b"stream\n")
562 f.write(stream)
563 f.write(b"\nendstream\n")
564 f.write(b"endobj\n")
565 return ref
567 def del_root(self) -> None:
568 if self.root_ref is None:
569 return
570 del self.xref_table[self.root_ref.object_id]
571 del self.xref_table[self.root[b"Pages"].object_id]
573 @staticmethod
574 def get_buf_from_file(f: IO[bytes]) -> bytes | mmap.mmap:
575 if hasattr(f, "getbuffer"):
576 return f.getbuffer()
577 elif hasattr(f, "getvalue"):
578 return f.getvalue()
579 else:
580 try:
581 return mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ)
582 except ValueError: # cannot mmap an empty file
583 return b""
585 def read_pdf_info(self) -> None:
586 assert self.buf is not None
587 self.file_size_total = len(self.buf)
588 self.file_size_this = self.file_size_total - self.start_offset
589 self.read_trailer()
590 check_format_condition(
591 self.trailer_dict.get(b"Root") is not None, "Root is missing"
592 )
593 self.root_ref = self.trailer_dict[b"Root"]
594 assert self.root_ref is not None
595 self.info_ref = self.trailer_dict.get(b"Info", None)
596 self.root = PdfDict(self.read_indirect(self.root_ref))
597 if self.info_ref is None:
598 self.info = PdfDict()
599 else:
600 self.info = PdfDict(self.read_indirect(self.info_ref))
601 check_format_condition(b"Type" in self.root, "/Type missing in Root")
602 check_format_condition(
603 self.root[b"Type"] == b"Catalog", "/Type in Root is not /Catalog"
604 )
605 check_format_condition(
606 self.root.get(b"Pages") is not None, "/Pages missing in Root"
607 )
608 check_format_condition(
609 isinstance(self.root[b"Pages"], IndirectReference),
610 "/Pages in Root is not an indirect reference",
611 )
612 self.pages_ref = self.root[b"Pages"]
613 assert self.pages_ref is not None
614 self.page_tree_root = self.read_indirect(self.pages_ref)
615 self.pages = self.linearize_page_tree(self.page_tree_root)
616 # save the original list of page references
617 # in case the user modifies, adds or deletes some pages
618 # and we need to rewrite the pages and their list
619 self.orig_pages = self.pages[:]
621 def next_object_id(self, offset: int | None = None) -> IndirectReference:
622 try:
623 # TODO: support reuse of deleted objects
624 reference = IndirectReference(max(self.xref_table.keys()) + 1, 0)
625 except ValueError:
626 reference = IndirectReference(1, 0)
627 if offset is not None:
628 self.xref_table[reference.object_id] = (offset, 0)
629 return reference
631 delimiter = rb"[][()<>{}/%]"
632 delimiter_or_ws = rb"[][()<>{}/%\000\011\012\014\015\040]"
633 whitespace = rb"[\000\011\012\014\015\040]"
634 whitespace_or_hex = rb"[\000\011\012\014\015\0400-9a-fA-F]"
635 whitespace_optional = whitespace + b"*"
636 whitespace_mandatory = whitespace + b"+"
637 # No "\012" aka "\n" or "\015" aka "\r":
638 whitespace_optional_no_nl = rb"[\000\011\014\040]*"
639 newline_only = rb"[\r\n]+"
640 newline = whitespace_optional_no_nl + newline_only + whitespace_optional_no_nl
641 re_trailer_end = re.compile(
642 whitespace_mandatory
643 + rb"trailer"
644 + whitespace_optional
645 + rb"<<(.*>>)"
646 + newline
647 + rb"startxref"
648 + newline
649 + rb"([0-9]+)"
650 + newline
651 + rb"%%EOF"
652 + whitespace_optional
653 + rb"$",
654 re.DOTALL,
655 )
656 re_trailer_prev = re.compile(
657 whitespace_optional
658 + rb"trailer"
659 + whitespace_optional
660 + rb"<<(.*?>>)"
661 + newline
662 + rb"startxref"
663 + newline
664 + rb"([0-9]+)"
665 + newline
666 + rb"%%EOF"
667 + whitespace_optional,
668 re.DOTALL,
669 )
671 def read_trailer(self) -> None:
672 assert self.buf is not None
673 search_start_offset = len(self.buf) - 16384
674 if search_start_offset < self.start_offset:
675 search_start_offset = self.start_offset
676 m = self.re_trailer_end.search(self.buf, search_start_offset)
677 check_format_condition(m is not None, "trailer end not found")
678 # make sure we found the LAST trailer
679 last_match = m
680 while m:
681 last_match = m
682 m = self.re_trailer_end.search(self.buf, m.start() + 16)
683 if not m:
684 m = last_match
685 assert m is not None
686 trailer_data = m.group(1)
687 self.last_xref_section_offset = int(m.group(2))
688 self.trailer_dict = self.interpret_trailer(trailer_data)
689 self.xref_table = XrefTable()
690 self.read_xref_table(xref_section_offset=self.last_xref_section_offset)
691 if b"Prev" in self.trailer_dict:
692 self.read_prev_trailer(self.trailer_dict[b"Prev"])
694 def read_prev_trailer(
695 self, xref_section_offset: int, processed_offsets: list[int] | None = None
696 ) -> None:
697 assert self.buf is not None
698 trailer_offset = self.read_xref_table(xref_section_offset=xref_section_offset)
699 m = self.re_trailer_prev.search(
700 self.buf[trailer_offset : trailer_offset + 16384]
701 )
702 check_format_condition(m is not None, "previous trailer not found")
703 assert m is not None
704 trailer_data = m.group(1)
705 check_format_condition(
706 int(m.group(2)) == xref_section_offset,
707 "xref section offset in previous trailer doesn't match what was expected",
708 )
709 trailer_dict = self.interpret_trailer(trailer_data)
710 if b"Prev" in trailer_dict:
711 if processed_offsets is None:
712 processed_offsets = []
713 processed_offsets.append(xref_section_offset)
714 check_format_condition(
715 trailer_dict[b"Prev"] not in processed_offsets, "trailer loop found"
716 )
717 self.read_prev_trailer(trailer_dict[b"Prev"], processed_offsets)
719 re_whitespace_optional = re.compile(whitespace_optional)
720 re_name = re.compile(
721 whitespace_optional
722 + rb"/([!-$&'*-.0-;=?-Z\\^-z|~]+)(?="
723 + delimiter_or_ws
724 + rb")"
725 )
726 re_dict_start = re.compile(whitespace_optional + rb"<<")
727 re_dict_end = re.compile(whitespace_optional + rb">>" + whitespace_optional)
729 @classmethod
730 def interpret_trailer(cls, trailer_data: bytes) -> dict[bytes, Any]:
731 trailer = {}
732 offset = 0
733 while True:
734 m = cls.re_name.match(trailer_data, offset)
735 if not m:
736 m = cls.re_dict_end.match(trailer_data, offset)
737 check_format_condition(
738 m is not None and m.end() == len(trailer_data),
739 "name not found in trailer, remaining data: "
740 + repr(trailer_data[offset:]),
741 )
742 break
743 key = cls.interpret_name(m.group(1))
744 assert isinstance(key, bytes)
745 value, value_offset = cls.get_value(trailer_data, m.end())
746 trailer[key] = value
747 if value_offset is None:
748 break
749 offset = value_offset
750 check_format_condition(
751 b"Size" in trailer and isinstance(trailer[b"Size"], int),
752 "/Size not in trailer or not an integer",
753 )
754 check_format_condition(
755 b"Root" in trailer and isinstance(trailer[b"Root"], IndirectReference),
756 "/Root not in trailer or not an indirect reference",
757 )
758 return trailer
760 re_hashes_in_name = re.compile(rb"([^#]*)(#([0-9a-fA-F]{2}))?")
762 @classmethod
763 def interpret_name(cls, raw: bytes, as_text: bool = False) -> str | bytes:
764 name = b""
765 for m in cls.re_hashes_in_name.finditer(raw):
766 if m.group(3):
767 name += m.group(1) + bytearray.fromhex(m.group(3).decode("us-ascii"))
768 else:
769 name += m.group(1)
770 if as_text:
771 return name.decode("utf-8")
772 else:
773 return bytes(name)
775 re_null = re.compile(whitespace_optional + rb"null(?=" + delimiter_or_ws + rb")")
776 re_true = re.compile(whitespace_optional + rb"true(?=" + delimiter_or_ws + rb")")
777 re_false = re.compile(whitespace_optional + rb"false(?=" + delimiter_or_ws + rb")")
778 re_int = re.compile(
779 whitespace_optional + rb"([-+]?[0-9]+)(?=" + delimiter_or_ws + rb")"
780 )
781 re_real = re.compile(
782 whitespace_optional
783 + rb"([-+]?([0-9]+\.[0-9]*|[0-9]*\.[0-9]+))(?="
784 + delimiter_or_ws
785 + rb")"
786 )
787 re_array_start = re.compile(whitespace_optional + rb"\[")
788 re_array_end = re.compile(whitespace_optional + rb"]")
789 re_string_hex = re.compile(
790 whitespace_optional + rb"<(" + whitespace_or_hex + rb"*)>"
791 )
792 re_string_lit = re.compile(whitespace_optional + rb"\(")
793 re_indirect_reference = re.compile(
794 whitespace_optional
795 + rb"([-+]?[0-9]+)"
796 + whitespace_mandatory
797 + rb"([-+]?[0-9]+)"
798 + whitespace_mandatory
799 + rb"R(?="
800 + delimiter_or_ws
801 + rb")"
802 )
803 re_indirect_def_start = re.compile(
804 whitespace_optional
805 + rb"([-+]?[0-9]+)"
806 + whitespace_mandatory
807 + rb"([-+]?[0-9]+)"
808 + whitespace_mandatory
809 + rb"obj(?="
810 + delimiter_or_ws
811 + rb")"
812 )
813 re_indirect_def_end = re.compile(
814 whitespace_optional + rb"endobj(?=" + delimiter_or_ws + rb")"
815 )
816 re_comment = re.compile(
817 rb"(" + whitespace_optional + rb"%[^\r\n]*" + newline + rb")*"
818 )
819 re_stream_start = re.compile(whitespace_optional + rb"stream\r?\n")
820 re_stream_end = re.compile(
821 whitespace_optional + rb"endstream(?=" + delimiter_or_ws + rb")"
822 )
824 @classmethod
825 def get_value(
826 cls,
827 data: bytes | bytearray | mmap.mmap,
828 offset: int,
829 expect_indirect: IndirectReference | None = None,
830 max_nesting: int = -1,
831 ) -> tuple[Any, int | None]:
832 if max_nesting == 0:
833 return None, None
834 m = cls.re_comment.match(data, offset)
835 if m:
836 offset = m.end()
837 m = cls.re_indirect_def_start.match(data, offset)
838 if m:
839 check_format_condition(
840 int(m.group(1)) > 0,
841 "indirect object definition: object ID must be greater than 0",
842 )
843 check_format_condition(
844 int(m.group(2)) >= 0,
845 "indirect object definition: generation must be non-negative",
846 )
847 check_format_condition(
848 expect_indirect is None
849 or expect_indirect
850 == IndirectReference(int(m.group(1)), int(m.group(2))),
851 "indirect object definition different than expected",
852 )
853 object, object_offset = cls.get_value(
854 data, m.end(), max_nesting=max_nesting - 1
855 )
856 if object_offset is None:
857 return object, None
858 m = cls.re_indirect_def_end.match(data, object_offset)
859 check_format_condition(
860 m is not None, "indirect object definition end not found"
861 )
862 assert m is not None
863 return object, m.end()
864 check_format_condition(
865 not expect_indirect, "indirect object definition not found"
866 )
867 m = cls.re_indirect_reference.match(data, offset)
868 if m:
869 check_format_condition(
870 int(m.group(1)) > 0,
871 "indirect object reference: object ID must be greater than 0",
872 )
873 check_format_condition(
874 int(m.group(2)) >= 0,
875 "indirect object reference: generation must be non-negative",
876 )
877 return IndirectReference(int(m.group(1)), int(m.group(2))), m.end()
878 m = cls.re_dict_start.match(data, offset)
879 if m:
880 offset = m.end()
881 result: dict[Any, Any] = {}
882 m = cls.re_dict_end.match(data, offset)
883 current_offset: int | None = offset
884 while not m:
885 assert current_offset is not None
886 key, current_offset = cls.get_value(
887 data, current_offset, max_nesting=max_nesting - 1
888 )
889 if current_offset is None:
890 return result, None
891 value, current_offset = cls.get_value(
892 data, current_offset, max_nesting=max_nesting - 1
893 )
894 result[key] = value
895 if current_offset is None:
896 return result, None
897 m = cls.re_dict_end.match(data, current_offset)
898 current_offset = m.end()
899 m = cls.re_stream_start.match(data, current_offset)
900 if m:
901 stream_len = result.get(b"Length")
902 if stream_len is None or not isinstance(stream_len, int):
903 msg = f"bad or missing Length in stream dict ({stream_len})"
904 raise PdfFormatError(msg)
905 stream_data = data[m.end() : m.end() + stream_len]
906 m = cls.re_stream_end.match(data, m.end() + stream_len)
907 check_format_condition(m is not None, "stream end not found")
908 assert m is not None
909 current_offset = m.end()
910 return PdfStream(PdfDict(result), stream_data), current_offset
911 return PdfDict(result), current_offset
912 m = cls.re_array_start.match(data, offset)
913 if m:
914 offset = m.end()
915 results = []
916 m = cls.re_array_end.match(data, offset)
917 current_offset = offset
918 while not m:
919 assert current_offset is not None
920 value, current_offset = cls.get_value(
921 data, current_offset, max_nesting=max_nesting - 1
922 )
923 results.append(value)
924 if current_offset is None:
925 return results, None
926 m = cls.re_array_end.match(data, current_offset)
927 return results, m.end()
928 m = cls.re_null.match(data, offset)
929 if m:
930 return None, m.end()
931 m = cls.re_true.match(data, offset)
932 if m:
933 return True, m.end()
934 m = cls.re_false.match(data, offset)
935 if m:
936 return False, m.end()
937 m = cls.re_name.match(data, offset)
938 if m:
939 return PdfName(cls.interpret_name(m.group(1))), m.end()
940 m = cls.re_int.match(data, offset)
941 if m:
942 return int(m.group(1)), m.end()
943 m = cls.re_real.match(data, offset)
944 if m:
945 # XXX Decimal instead of float???
946 return float(m.group(1)), m.end()
947 m = cls.re_string_hex.match(data, offset)
948 if m:
949 # filter out whitespace
950 hex_string = bytearray(
951 b for b in m.group(1) if b in b"0123456789abcdefABCDEF"
952 )
953 if len(hex_string) % 2 == 1:
954 # append a 0 if the length is not even - yes, at the end
955 hex_string.append(ord(b"0"))
956 return bytearray.fromhex(hex_string.decode("us-ascii")), m.end()
957 m = cls.re_string_lit.match(data, offset)
958 if m:
959 return cls.get_literal_string(data, m.end())
960 # return None, offset # fallback (only for debugging)
961 msg = f"unrecognized object: {repr(data[offset : offset + 32])}"
962 raise PdfFormatError(msg)
964 re_lit_str_token = re.compile(
965 rb"(\\[nrtbf()\\])|(\\[0-9]{1,3})|(\\(\r\n|\r|\n))|(\r\n|\r|\n)|(\()|(\))"
966 )
967 escaped_chars = {
968 b"n": b"\n",
969 b"r": b"\r",
970 b"t": b"\t",
971 b"b": b"\b",
972 b"f": b"\f",
973 b"(": b"(",
974 b")": b")",
975 b"\\": b"\\",
976 ord(b"n"): b"\n",
977 ord(b"r"): b"\r",
978 ord(b"t"): b"\t",
979 ord(b"b"): b"\b",
980 ord(b"f"): b"\f",
981 ord(b"("): b"(",
982 ord(b")"): b")",
983 ord(b"\\"): b"\\",
984 }
986 @classmethod
987 def get_literal_string(
988 cls, data: bytes | bytearray | mmap.mmap, offset: int
989 ) -> tuple[bytes, int]:
990 nesting_depth = 0
991 result = bytearray()
992 for m in cls.re_lit_str_token.finditer(data, offset):
993 result.extend(data[offset : m.start()])
994 if m.group(1):
995 result.extend(cls.escaped_chars[m.group(1)[1]])
996 elif m.group(2):
997 result.append(int(m.group(2)[1:], 8))
998 elif m.group(3):
999 pass
1000 elif m.group(5):
1001 result.extend(b"\n")
1002 elif m.group(6):
1003 result.extend(b"(")
1004 nesting_depth += 1
1005 elif m.group(7):
1006 if nesting_depth == 0:
1007 return bytes(result), m.end()
1008 result.extend(b")")
1009 nesting_depth -= 1
1010 offset = m.end()
1011 msg = "unfinished literal string"
1012 raise PdfFormatError(msg)
1014 re_xref_section_start = re.compile(whitespace_optional + rb"xref" + newline)
1015 re_xref_subsection_start = re.compile(
1016 whitespace_optional
1017 + rb"([0-9]+)"
1018 + whitespace_mandatory
1019 + rb"([0-9]+)"
1020 + whitespace_optional
1021 + newline_only
1022 )
1023 re_xref_entry = re.compile(rb"([0-9]{10}) ([0-9]{5}) ([fn])( \r| \n|\r\n)")
1025 def read_xref_table(self, xref_section_offset: int) -> int:
1026 assert self.buf is not None
1027 subsection_found = False
1028 m = self.re_xref_section_start.match(
1029 self.buf, xref_section_offset + self.start_offset
1030 )
1031 check_format_condition(m is not None, "xref section start not found")
1032 assert m is not None
1033 offset = m.end()
1034 while True:
1035 m = self.re_xref_subsection_start.match(self.buf, offset)
1036 if not m:
1037 check_format_condition(
1038 subsection_found, "xref subsection start not found"
1039 )
1040 break
1041 subsection_found = True
1042 offset = m.end()
1043 first_object = int(m.group(1))
1044 num_objects = int(m.group(2))
1045 for i in range(first_object, first_object + num_objects):
1046 m = self.re_xref_entry.match(self.buf, offset)
1047 check_format_condition(m is not None, "xref entry not found")
1048 assert m is not None
1049 offset = m.end()
1050 is_free = m.group(3) == b"f"
1051 if not is_free:
1052 generation = int(m.group(2))
1053 new_entry = (int(m.group(1)), generation)
1054 if i not in self.xref_table:
1055 self.xref_table[i] = new_entry
1056 return offset
1058 def read_indirect(self, ref: IndirectReference, max_nesting: int = -1) -> Any:
1059 offset, generation = self.xref_table[ref[0]]
1060 check_format_condition(
1061 generation == ref[1],
1062 f"expected to find generation {ref[1]} for object ID {ref[0]} in xref "
1063 f"table, instead found generation {generation} at offset {offset}",
1064 )
1065 assert self.buf is not None
1066 value = self.get_value(
1067 self.buf,
1068 offset + self.start_offset,
1069 expect_indirect=IndirectReference(*ref),
1070 max_nesting=max_nesting,
1071 )[0]
1072 self.cached_objects[ref] = value
1073 return value
1075 def linearize_page_tree(
1076 self, node: PdfDict | None = None
1077 ) -> list[IndirectReference]:
1078 page_node = node if node is not None else self.page_tree_root
1079 check_format_condition(
1080 page_node[b"Type"] == b"Pages", "/Type of page tree node is not /Pages"
1081 )
1082 pages = []
1083 for kid in page_node[b"Kids"]:
1084 kid_object = self.read_indirect(kid)
1085 if kid_object[b"Type"] == b"Page":
1086 pages.append(kid)
1087 else:
1088 pages.extend(self.linearize_page_tree(node=kid_object))
1089 return pages