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LibPDF: Keep track of the current object index/generation while Parsing

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This information is required to decrypt encrypted strings/streams.
This commit is contained in:
Matthew Olsson 2022-03-21 11:26:31 -07:00 • committed by Andreas Kling
parent 5b316462b2
commit a8de9cf541
2 changed files with 20 additions and 4 deletions
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18
Userland/Libraries/LibPDF/Parser.cpp
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@ -613,20 +613,26 @@ PDFErrorOr<Value> Parser::parse_possible_indirect_value_or_ref()
if (m_reader.matches("obj")) {
m_reader.discard();
return TRY(parse_indirect_value(first_number.get<int>(), second_number.value().get<int>()));
auto index = first_number.get<int>();
auto generation = second_number.value().get<int>();
VERIFY(index >= 0);
VERIFY(generation >= 0);
return TRY(parse_indirect_value(index, generation));
}
m_reader.load();
return first_number;
}
PDFErrorOr<NonnullRefPtr<IndirectValue>> Parser::parse_indirect_value(int index, int generation)
PDFErrorOr<NonnullRefPtr<IndirectValue>> Parser::parse_indirect_value(u32 index, u32 generation)
{
if (!m_reader.matches("obj"))
return error("Expected \"obj\" at beginning of indirect value");
m_reader.move_by(3);
if (matches_eol())
consume_eol();
push_reference({ index, generation });
auto value = TRY(parse_value());
if (!m_reader.matches("endobj"))
return error("Expected \"endobj\" at end of indirect value");
@ -634,6 +640,8 @@ PDFErrorOr<NonnullRefPtr<IndirectValue>> Parser::parse_indirect_value(int index,
consume(6);
consume_whitespace();
pop_reference();
return make_object<IndirectValue>(index, generation, value);
}
@ -641,7 +649,11 @@ PDFErrorOr<NonnullRefPtr<IndirectValue>> Parser::parse_indirect_value()
{
auto first_number = TRY(parse_number());
auto second_number = TRY(parse_number());
return parse_indirect_value(first_number.get<int>(), second_number.get<int>());
auto index = first_number.get<int>();
auto generation = second_number.get<int>();
VERIFY(index >= 0);
VERIFY(generation >= 0);
return parse_indirect_value(index, generation);
}
PDFErrorOr<Value> Parser::parse_number()