# Copyright (c) 2006, Mathieu Fenniak
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
# * The name of the author may not be used to endorse or promote products
# derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
"""Utility functions for PDF library."""
__author__ = "Mathieu Fenniak"
__author_email__ = "biziqe@mathieu.fenniak.net"
import functools
import logging
import re
import sys
import warnings
from dataclasses import dataclass
from datetime import datetime, timezone
from io import DEFAULT_BUFFER_SIZE, BytesIO
from os import SEEK_CUR
from typing import (
IO,
Any,
Dict,
List,
Optional,
Pattern,
Tuple,
Union,
cast,
overload,
)
if sys.version_info[:2] >= (3, 10):
# Python 3.10+: https://www.python.org/dev/peps/pep-0484/
from typing import TypeAlias
else:
from typing_extensions import TypeAlias
from .errors import (
STREAM_TRUNCATED_PREMATURELY,
DeprecationError,
PdfStreamError,
)
TransformationMatrixType: TypeAlias = Tuple[
Tuple[float, float, float], Tuple[float, float, float], Tuple[float, float, float]
]
CompressedTransformationMatrix: TypeAlias = Tuple[
float, float, float, float, float, float
]
StreamType = IO[Any]
StrByteType = Union[str, StreamType]
def parse_iso8824_date(text: Optional[str]) -> Optional[datetime]:
orgtext = text
if text is None:
return None
if text[0].isdigit():
text = "D:" + text
if text.endswith(("Z", "z")):
text += "0000"
text = text.replace("z", "+").replace("Z", "+").replace("'", "")
i = max(text.find("+"), text.find("-"))
if i > 0 and i != len(text) - 5:
text += "00"
for f in (
"D:%Y",
"D:%Y%m",
"D:%Y%m%d",
"D:%Y%m%d%H",
"D:%Y%m%d%H%M",
"D:%Y%m%d%H%M%S",
"D:%Y%m%d%H%M%S%z",
):
try:
d = datetime.strptime(text, f) # noqa: DTZ007
except ValueError:
continue
else:
if text.endswith("+0000"):
d = d.replace(tzinfo=timezone.utc)
return d
raise ValueError(f"Can not convert date: {orgtext}")
def _get_max_pdf_version_header(header1: str, header2: str) -> str:
versions = (
"%PDF-1.3",
"%PDF-1.4",
"%PDF-1.5",
"%PDF-1.6",
"%PDF-1.7",
"%PDF-2.0",
)
pdf_header_indices = []
if header1 in versions:
pdf_header_indices.append(versions.index(header1))
if header2 in versions:
pdf_header_indices.append(versions.index(header2))
if len(pdf_header_indices) == 0:
raise ValueError(f"neither {header1!r} nor {header2!r} are proper headers")
return versions[max(pdf_header_indices)]
def read_until_whitespace(stream: StreamType, maxchars: Optional[int] = None) -> bytes:
"""
Read non-whitespace characters and return them.
Stops upon encountering whitespace or when maxchars is reached.
Args:
stream: The data stream from which was read.
maxchars: The maximum number of bytes returned; by default unlimited.
Returns:
The data which was read.
"""
txt = b""
while True:
tok = stream.read(1)
if tok.isspace() or not tok:
break
txt += tok
if len(txt) == maxchars:
break
return txt
def read_non_whitespace(stream: StreamType) -> bytes:
"""
Find and read the next non-whitespace character (ignores whitespace).
Args:
stream: The data stream from which was read.
Returns:
The data which was read.
"""
tok = stream.read(1)
while tok in WHITESPACES:
tok = stream.read(1)
return tok
def skip_over_whitespace(stream: StreamType) -> bool:
"""
Similar to read_non_whitespace, but return a boolean if more than one
whitespace character was read.
Args:
stream: The data stream from which was read.
Returns:
True if more than one whitespace was skipped, otherwise return False.
"""
tok = WHITESPACES[0]
cnt = 0
while tok in WHITESPACES:
tok = stream.read(1)
cnt += 1
return cnt > 1
def check_if_whitespace_only(value: bytes) -> bool:
"""
Check if the given value consists of whitespace characters only.
Args:
value: The bytes to check.
Returns:
True if the value only has whitespace characters, otherwise return False.
"""
for index in range(len(value)):
current = value[index : index + 1]
if current not in WHITESPACES:
return False
return True
def skip_over_comment(stream: StreamType) -> None:
tok = stream.read(1)
stream.seek(-1, 1)
if tok == b"%":
while tok not in (b"\n", b"\r"):
tok = stream.read(1)
def read_until_regex(stream: StreamType, regex: Pattern[bytes]) -> bytes:
"""
Read until the regular expression pattern matched (ignore the match).
Treats EOF on the underlying stream as the end of the token to be matched.
Args:
regex: re.Pattern
Returns:
The read bytes.
"""
name = b""
while True:
tok = stream.read(16)
if not tok:
return name
m = regex.search(name + tok)
if m is not None:
stream.seek(m.start() - (len(name) + len(tok)), 1)
name = (name + tok)[: m.start()]
break
name += tok
return name
def read_block_backwards(stream: StreamType, to_read: int) -> bytes:
"""
Given a stream at position X, read a block of size to_read ending at position X.
This changes the stream's position to the beginning of where the block was
read.
Args:
stream:
to_read:
Returns:
The data which was read.
"""
if stream.tell() < to_read:
raise PdfStreamError("Could not read malformed PDF file")
# Seek to the start of the block we want to read.
stream.seek(-to_read, SEEK_CUR)
read = stream.read(to_read)
# Seek to the start of the block we read after reading it.
stream.seek(-to_read, SEEK_CUR)
return read
def read_previous_line(stream: StreamType) -> bytes:
"""
Given a byte stream with current position X, return the previous line.
All characters between the first CR/LF byte found before X
(or, the start of the file, if no such byte is found) and position X
After this call, the stream will be positioned one byte after the
first non-CRLF character found beyond the first CR/LF byte before X,
or, if no such byte is found, at the beginning of the stream.
Args:
stream: StreamType:
Returns:
The data which was read.
"""
line_content = []
found_crlf = False
if stream.tell() == 0:
raise PdfStreamError(STREAM_TRUNCATED_PREMATURELY)
while True:
to_read = min(DEFAULT_BUFFER_SIZE, stream.tell())
if to_read == 0:
break
# Read the block. After this, our stream will be one
# beyond the initial position.
block = read_block_backwards(stream, to_read)
idx = len(block) - 1
if not found_crlf:
# We haven't found our first CR/LF yet.
# Read off characters until we hit one.
while idx >= 0 and block[idx] not in b"\r\n":
idx -= 1
if idx >= 0:
found_crlf = True
if found_crlf:
# We found our first CR/LF already (on this block or
# a previous one).
# Our combined line is the remainder of the block
# plus any previously read blocks.
line_content.append(block[idx + 1 :])
# Continue to read off any more CRLF characters.
while idx >= 0 and block[idx] in b"\r\n":
idx -= 1
else:
# Didn't find CR/LF yet - add this block to our
# previously read blocks and continue.
line_content.append(block)
if idx >= 0:
# We found the next non-CRLF character.
# Set the stream position correctly, then break
stream.seek(idx + 1, SEEK_CUR)
break
# Join all the blocks in the line (which are in reverse order)
return b"".join(line_content[::-1])
def matrix_multiply(
a: TransformationMatrixType, b: TransformationMatrixType
) -> TransformationMatrixType:
return tuple( # type: ignore[return-value]
tuple(sum(float(i) * float(j) for i, j in zip(row, col)) for col in zip(*b))
for row in a
)
def mark_location(stream: StreamType) -> None:
"""Create text file showing current location in context."""
# Mainly for debugging
radius = 5000
stream.seek(-radius, 1)
with open("pypdf_pdfLocation.txt", "wb") as output_fh:
output_fh.write(stream.read(radius))
output_fh.write(b"HERE")
output_fh.write(stream.read(radius))
stream.seek(-radius, 1)
B_CACHE: Dict[Union[str, bytes], bytes] = {}
def b_(s: Union[str, bytes]) -> bytes:
if isinstance(s, bytes):
return s
bc = B_CACHE
if s in bc:
return bc[s]
try:
r = s.encode("latin-1")
if len(s) < 2:
bc[s] = r
return r
except Exception:
r = s.encode("utf-8")
if len(s) < 2:
bc[s] = r
return r
def str_(b: Any) -> str:
if isinstance(b, bytes):
return b.decode("latin-1")
else:
return str(b) # will return b.__str__() if defined
@overload
def ord_(b: str) -> int:
...
@overload
def ord_(b: bytes) -> bytes:
...
@overload
def ord_(b: int) -> int:
...
def ord_(b: Union[int, str, bytes]) -> Union[int, bytes]:
if isinstance(b, str):
return ord(b)
return b
WHITESPACES = (b" ", b"\n", b"\r", b"\t", b"\x00")
WHITESPACES_AS_BYTES = b"".join(WHITESPACES)
WHITESPACES_AS_REGEXP = b"[" + WHITESPACES_AS_BYTES + b"]"
def paeth_predictor(left: int, up: int, up_left: int) -> int:
p = left + up - up_left
dist_left = abs(p - left)
dist_up = abs(p - up)
dist_up_left = abs(p - up_left)
if dist_left <= dist_up and dist_left <= dist_up_left:
return left
elif dist_up <= dist_up_left:
return up
else:
return up_left
def deprecate(msg: str, stacklevel: int = 3) -> None:
warnings.warn(msg, DeprecationWarning, stacklevel=stacklevel)
def deprecation(msg: str) -> None:
raise DeprecationError(msg)
def deprecate_with_replacement(old_name: str, new_name: str, removed_in: str) -> None:
"""Raise an exception that a feature will be removed, but has a replacement."""
deprecate(f"{old_name} is deprecated and will be removed in pypdf {removed_in}. Use {new_name} instead.", 4)
def deprecation_with_replacement(old_name: str, new_name: str, removed_in: str) -> None:
"""Raise an exception that a feature was already removed, but has a replacement."""
deprecation(f"{old_name} is deprecated and was removed in pypdf {removed_in}. Use {new_name} instead.")
def deprecate_no_replacement(name: str, removed_in: str) -> None:
"""Raise an exception that a feature will be removed without replacement."""
deprecate(f"{name} is deprecated and will be removed in pypdf {removed_in}.", 4)
def deprecation_no_replacement(name: str, removed_in: str) -> None:
"""Raise an exception that a feature was already removed without replacement."""
deprecation(f"{name} is deprecated and was removed in pypdf {removed_in}.")
def logger_error(msg: str, src: str) -> None:
"""
Use this instead of logger.error directly.
That allows people to overwrite it more easily.
See the docs on when to use which:
https://pypdf.readthedocs.io/en/latest/user/suppress-warnings.html
"""
logging.getLogger(src).error(msg)
def logger_warning(msg: str, src: str) -> None:
"""
Use this instead of logger.warning directly.
That allows people to overwrite it more easily.
## Exception, warnings.warn, logger_warning
- Exceptions should be used if the user should write code that deals with
an error case, e.g. the PDF being completely broken.
- warnings.warn should be used if the user needs to fix their code, e.g.
DeprecationWarnings
- logger_warning should be used if the user needs to know that an issue was
handled by pypdf, e.g. a non-compliant PDF being read in a way that
pypdf could apply a robustness fix to still read it. This applies mainly
to strict=False mode.
"""
logging.getLogger(src).warning(msg)
def rename_kwargs(
func_name: str, kwargs: Dict[str, Any], aliases: Dict[str, str], fail: bool = False
) -> None:
"""
Helper function to deprecate arguments.
Args:
func_name: Name of the function to be deprecated
kwargs:
aliases:
fail:
"""
for old_term, new_term in aliases.items():
if old_term in kwargs:
if fail:
raise DeprecationError(
f"{old_term} is deprecated as an argument. Use {new_term} instead"
)
if new_term in kwargs:
raise TypeError(
f"{func_name} received both {old_term} and {new_term} as "
f"an argument. {old_term} is deprecated. "
f"Use {new_term} instead."
)
kwargs[new_term] = kwargs.pop(old_term)
warnings.warn(
message=(
f"{old_term} is deprecated as an argument. Use {new_term} instead"
),
category=DeprecationWarning,
)
def _human_readable_bytes(bytes: int) -> str:
if bytes < 10**3:
return f"{bytes} Byte"
elif bytes < 10**6:
return f"{bytes / 10**3:.1f} kB"
elif bytes < 10**9:
return f"{bytes / 10**6:.1f} MB"
else:
return f"{bytes / 10**9:.1f} GB"
# The following class has been copied from Django:
# https://github.com/django/django/blob/adae619426b6f50046b3daaa744db52989c9d6db/django/utils/functional.py#L51-L65
#
# Original license:
#
# ---------------------------------------------------------------------------------
# Copyright (c) Django Software Foundation and individual contributors.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without modification,
# are permitted provided that the following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
#
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# 3. Neither the name of Django nor the names of its contributors may be used
# to endorse or promote products derived from this software without
# specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
# ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
# ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
# ---------------------------------------------------------------------------------
class classproperty: # noqa: N801
"""
Decorator that converts a method with a single cls argument into a property
that can be accessed directly from the class.
"""
def __init__(self, method=None): # type: ignore # noqa: ANN001
self.fget = method
def __get__(self, instance, cls=None) -> Any: # type: ignore # noqa: ANN001
return self.fget(cls)
def getter(self, method): # type: ignore # noqa: ANN001, ANN202
self.fget = method
return self
@dataclass
class File:
from .generic import IndirectObject
name: str
data: bytes
image: Optional[Any] = None # optional ; direct image access
indirect_reference: Optional[IndirectObject] = None # optional ; link to PdfObject
def __str__(self) -> str:
return f"{self.__class__.__name__}(name={self.name}, data: {_human_readable_bytes(len(self.data))})"
def __repr__(self) -> str:
return self.__str__()[:-1] + f", hash: {hash(self.data)})"
@dataclass
class ImageFile(File):
from .generic import IndirectObject
image: Optional[Any] = None # optional ; direct PIL image access
indirect_reference: Optional[IndirectObject] = None # optional ; link to PdfObject
def replace(self, new_image: Any, **kwargs: Any) -> None:
"""
Replace the Image with a new PIL image.
Args:
new_image (PIL.Image.Image): The new PIL image to replace the existing image.
**kwargs: Additional keyword arguments to pass to `Image.Image.save()`.
Raises:
TypeError: If the image is inline or in a PdfReader.
TypeError: If the image does not belong to a PdfWriter.
TypeError: If `new_image` is not a PIL Image.
Note:
This method replaces the existing image with a new image.
It is not allowed for inline images or images within a PdfReader.
The `kwargs` parameter allows passing additional parameters
to `Image.Image.save()`, such as quality.
"""
from PIL import Image
from ._reader import PdfReader
# to prevent circular import
from .filters import _xobj_to_image
from .generic import DictionaryObject, PdfObject
if self.indirect_reference is None:
raise TypeError("Can not update an inline image")
if not hasattr(self.indirect_reference.pdf, "_id_translated"):
raise TypeError("Can not update an image not belonging to a PdfWriter")
if not isinstance(new_image, Image.Image):
raise TypeError("new_image shall be a PIL Image")
b = BytesIO()
new_image.save(b, "PDF", **kwargs)
reader = PdfReader(b)
assert reader.pages[0].images[0].indirect_reference is not None
self.indirect_reference.pdf._objects[self.indirect_reference.idnum - 1] = (
reader.pages[0].images[0].indirect_reference.get_object()
)
cast(
PdfObject, self.indirect_reference.get_object()
).indirect_reference = self.indirect_reference
# change the object attributes
extension, byte_stream, img = _xobj_to_image(
cast(DictionaryObject, self.indirect_reference.get_object())
)
assert extension is not None
self.name = self.name[: self.name.rfind(".")] + extension
self.data = byte_stream
self.image = img
@functools.total_ordering
class Version:
COMPONENT_PATTERN = re.compile(r"^(\d+)(.*)$")
def __init__(self, version_str: str) -> None:
self.version_str = version_str
self.components = self._parse_version(version_str)
def _parse_version(self, version_str: str) -> List[Tuple[int, str]]:
components = version_str.split(".")
parsed_components = []
for component in components:
match = Version.COMPONENT_PATTERN.match(component)
if not match:
parsed_components.append((0, component))
continue
integer_prefix = match.group(1)
suffix = match.group(2)
if integer_prefix is None:
integer_prefix = 0
parsed_components.append((int(integer_prefix), suffix))
return parsed_components
def __eq__(self, other: object) -> bool:
if not isinstance(other, Version):
return False
return self.components == other.components
def __lt__(self, other: Any) -> bool:
if not isinstance(other, Version):
raise ValueError(f"Version cannot be compared against {type(other)}")
min_len = min(len(self.components), len(other.components))
for i in range(min_len):
self_value, self_suffix = self.components[i]
other_value, other_suffix = other.components[i]
if self_value < other_value:
return True
elif self_value > other_value:
return False
if self_suffix < other_suffix:
return True
elif self_suffix > other_suffix:
return False
return len(self.components) < len(other.components)
