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Log warning and continue gracefully if errors in cmap (#731) 

* Log warning and continue gracefully if errors in cmap

* Fix nox testing

* Also log warning if cid range is larger than actual code

* Format with black

* Add docstring

* Add CHANGELOG.md

* Restore running cmapdb.py directly
pull/747/head
Pieter Marsman 2022-03-21 19:39:53 +01:00 committed by GitHub
parent 13021c9875
commit 894dabf264
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 75 additions and 30 deletions
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2
CHANGELOG.md
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@ -8,6 +8,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
### Fixed
- `IndexError` when handling invalid bfrange code map in
CMap ([#731](https://github.com/pdfminer/pdfminer.six/pull/731))
- `TypeError` in lzw.py when `self.table` is not set ([#732](https://github.com/pdfminer/pdfminer.six/pull/732))
- `TypeError` in encodingdb.py when name of unicode is not
str ([#733](https://github.com/pdfminer/pdfminer.six/pull/733))

103
pdfminer/cmapdb.py
View File

@ -29,6 +29,7 @@ from typing import (
Tuple,
Union,
cast,
Set,
)
from .encodingdb import name2unicode
@ -285,6 +286,7 @@ class CMapParser(PSStackParser[PSKeyword]):
self.cmap = cmap
# some ToUnicode maps don't have "begincmap" keyword.
self._in_cmap = True
self._warnings: Set[str] = set()
return
def run(self) -> None:
@ -312,16 +314,22 @@ class CMapParser(PSStackParser[PSKeyword]):
KEYWORD_ENDNOTDEFRANGE = KWD(b"endnotdefrange")
def do_keyword(self, pos: int, token: PSKeyword) -> None:
"""ToUnicode CMaps
See Section 5.9.2 - ToUnicode CMaps of the PDF Reference.
"""
if token is self.KEYWORD_BEGINCMAP:
self._in_cmap = True
self.popall()
return
elif token is self.KEYWORD_ENDCMAP:
self._in_cmap = False
return
if not self._in_cmap:
return
#
if token is self.KEYWORD_DEF:
try:
((_, k), (_, v)) = self.pop(2)
@ -350,33 +358,47 @@ class CMapParser(PSStackParser[PSKeyword]):
if token is self.KEYWORD_BEGINCIDRANGE:
self.popall()
return
if token is self.KEYWORD_ENDCIDRANGE:
objs = [obj for (__, obj) in self.popall()]
for (s, e, cid) in choplist(3, objs):
if (
not isinstance(s, bytes)
or not isinstance(e, bytes)
or not isinstance(cid, int)
or len(s) != len(e)
):
for (start_byte, end_byte, cid) in choplist(3, objs):
if not isinstance(start_byte, bytes):
self._warn_once("The start object of begincidrange is not a byte.")
continue
sprefix = s[:-4]
eprefix = e[:-4]
if sprefix != eprefix:
if not isinstance(end_byte, bytes):
self._warn_once("The end object of begincidrange is not a byte.")
continue
svar = s[-4:]
evar = e[-4:]
s1 = nunpack(svar)
e1 = nunpack(evar)
if not isinstance(cid, int):
self._warn_once("The cid object of begincidrange is not a byte.")
continue
if len(start_byte) != len(end_byte):
self._warn_once(
"The start and end byte of begincidrange have "
"different lengths."
)
continue
start_prefix = start_byte[:-4]
end_prefix = end_byte[:-4]
if start_prefix != end_prefix:
self._warn_once(
"The prefix of the start and end byte of "
"begincidrange are not the same."
)
continue
svar = start_byte[-4:]
evar = end_byte[-4:]
start = nunpack(svar)
end = nunpack(evar)
vlen = len(svar)
for i in range(e1 - s1 + 1):
x = sprefix + struct.pack(">L", s1 + i)[-vlen:]
for i in range(end - start + 1):
x = start_prefix + struct.pack(">L", start + i)[-vlen:]
self.cmap.add_cid2unichr(cid + i, x)
return
if token is self.KEYWORD_BEGINCIDCHAR:
self.popall()
return
if token is self.KEYWORD_ENDCIDCHAR:
objs = [obj for (__, obj) in self.popall()]
for (cid, code) in choplist(2, objs):
@ -387,34 +409,44 @@ class CMapParser(PSStackParser[PSKeyword]):
if token is self.KEYWORD_BEGINBFRANGE:
self.popall()
return
if token is self.KEYWORD_ENDBFRANGE:
objs = [obj for (__, obj) in self.popall()]
for (s, e, code) in choplist(3, objs):
if (
not isinstance(s, bytes)
or not isinstance(e, bytes)
or len(s) != len(e)
):
for (start_byte, end_byte, code) in choplist(3, objs):
if not isinstance(start_byte, bytes):
self._warn_once("The start object is not a byte.")
continue
s1 = nunpack(s)
e1 = nunpack(e)
if not isinstance(end_byte, bytes):
self._warn_once("The end object is not a byte.")
continue
if len(start_byte) != len(end_byte):
self._warn_once("The start and end byte have different lengths.")
continue
start = nunpack(start_byte)
end = nunpack(end_byte)
if isinstance(code, list):
for i in range(e1 - s1 + 1):
self.cmap.add_cid2unichr(s1 + i, code[i])
if len(code) != end - start + 1:
self._warn_once(
"The difference between the start and end "
"offsets does not match the code length."
)
for cid, unicode_value in zip(range(start, end + 1), code):
self.cmap.add_cid2unichr(cid, unicode_value)
else:
assert isinstance(code, bytes)
var = code[-4:]
base = nunpack(var)
prefix = code[:-4]
vlen = len(var)
for i in range(e1 - s1 + 1):
for i in range(end - start + 1):
x = prefix + struct.pack(">L", base + i)[-vlen:]
self.cmap.add_cid2unichr(s1 + i, x)
self.cmap.add_cid2unichr(start + i, x)
return
if token is self.KEYWORD_BEGINBFCHAR:
self.popall()
return
if token is self.KEYWORD_ENDBFCHAR:
objs = [obj for (__, obj) in self.popall()]
for (cid, code) in choplist(2, objs):
@ -425,12 +457,23 @@ class CMapParser(PSStackParser[PSKeyword]):
if token is self.KEYWORD_BEGINNOTDEFRANGE:
self.popall()
return
if token is self.KEYWORD_ENDNOTDEFRANGE:
self.popall()
return
self.push((pos, token))
return
def _warn_once(self, msg: str) -> None:
"""Warn once for each unique message"""
if msg not in self._warnings:
self._warnings.add(msg)
base_msg = (
"Ignoring (part of) ToUnicode map because the PDF data "
"does not conform to the format. This could result in "
"(cid) values in the output. "
)
log.warning(base_msg + msg)
def main(argv: List[str]) -> None: