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LibPDF: Make Filter::decode() return ErrorOr

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This commit is contained in:
Sam Atkins 2022-01-20 17:26:37 +00:00 • committed by Andreas Kling
parent c388a879d7
commit fa3c61cf5a
3 changed files with 33 additions and 41 deletions
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47
Userland/Libraries/LibPDF/Filter.cpp
View file

@ -11,7 +11,7 @@
namespace PDF {
Optional<ByteBuffer> Filter::decode(ReadonlyBytes bytes, FlyString const& encoding_type)
ErrorOr<ByteBuffer> Filter::decode(ReadonlyBytes bytes, FlyString const& encoding_type)
{
if (encoding_type == CommonNames::ASCIIHexDecode)
return decode_ascii_hex(bytes);
@ -34,34 +34,26 @@ Optional<ByteBuffer> Filter::decode(ReadonlyBytes bytes, FlyString const& encodi
if (encoding_type == CommonNames::Crypt)
return decode_crypt(bytes);
return {};
return Error::from_string_literal("Unrecognized filter encoding");
}
Optional<ByteBuffer> Filter::decode_ascii_hex(ReadonlyBytes bytes)
ErrorOr<ByteBuffer> Filter::decode_ascii_hex(ReadonlyBytes bytes)
{
if (bytes.size() % 2 == 0) {
auto decode_result = decode_hex(bytes);
if (decode_result.is_error())
return {};
return decode_result.release_value();
}
if (bytes.size() % 2 == 0)
return decode_hex(bytes);
// FIXME: Integrate this padding into AK/Hex?
auto output_result = ByteBuffer::create_zeroed(bytes.size() / 2 + 1);
if (output_result.is_error())
return {};
auto output = output_result.release_value();
auto output = TRY(ByteBuffer::create_zeroed(bytes.size() / 2 + 1));
for (size_t i = 0; i < bytes.size() / 2; ++i) {
const auto c1 = decode_hex_digit(static_cast<char>(bytes[i * 2]));
if (c1 >= 16)
return {};
return Error::from_string_literal("Hex string contains invalid digit");
const auto c2 = decode_hex_digit(static_cast<char>(bytes[i * 2 + 1]));
if (c2 >= 16)
return {};
return Error::from_string_literal("Hex string contains invalid digit");
output[i] = (c1 << 4) + c2;
}
@ -72,7 +64,7 @@ Optional<ByteBuffer> Filter::decode_ascii_hex(ReadonlyBytes bytes)
return { move(output) };
};
Optional<ByteBuffer> Filter::decode_ascii85(ReadonlyBytes bytes)
ErrorOr<ByteBuffer> Filter::decode_ascii85(ReadonlyBytes bytes)
{
Vector<u8> buff;
buff.ensure_capacity(bytes.size());
@ -124,19 +116,16 @@ Optional<ByteBuffer> Filter::decode_ascii85(ReadonlyBytes bytes)
buff.append(reinterpret_cast<u8*>(&number)[3 - i]);
}
auto result = ByteBuffer::copy(buff.span());
if (result.is_error())
return {};
return result.release_value();
return ByteBuffer::copy(buff.span());
};
Optional<ByteBuffer> Filter::decode_lzw(ReadonlyBytes)
ErrorOr<ByteBuffer> Filter::decode_lzw(ReadonlyBytes)
{
dbgln("LZW decoding is not supported");
VERIFY_NOT_REACHED();
};
Optional<ByteBuffer> Filter::decode_flate(ReadonlyBytes bytes)
ErrorOr<ByteBuffer> Filter::decode_flate(ReadonlyBytes bytes)
{
// FIXME: The spec says Flate decoding is "based on" zlib, does that mean they
// aren't exactly the same?
@ -146,37 +135,37 @@ Optional<ByteBuffer> Filter::decode_flate(ReadonlyBytes bytes)
return buff.value();
};
Optional<ByteBuffer> Filter::decode_run_length(ReadonlyBytes)
ErrorOr<ByteBuffer> Filter::decode_run_length(ReadonlyBytes)
{
// FIXME: Support RunLength decoding
TODO();
};
Optional<ByteBuffer> Filter::decode_ccitt(ReadonlyBytes)
ErrorOr<ByteBuffer> Filter::decode_ccitt(ReadonlyBytes)
{
// FIXME: Support CCITT decoding
TODO();
};
Optional<ByteBuffer> Filter::decode_jbig2(ReadonlyBytes)
ErrorOr<ByteBuffer> Filter::decode_jbig2(ReadonlyBytes)
{
// FIXME: Support JBIG2 decoding
TODO();
};
Optional<ByteBuffer> Filter::decode_dct(ReadonlyBytes)
ErrorOr<ByteBuffer> Filter::decode_dct(ReadonlyBytes)
{
// FIXME: Support dct decoding
TODO();
};
Optional<ByteBuffer> Filter::decode_jpx(ReadonlyBytes)
ErrorOr<ByteBuffer> Filter::decode_jpx(ReadonlyBytes)
{
// FIXME: Support JPX decoding
TODO();
};
Optional<ByteBuffer> Filter::decode_crypt(ReadonlyBytes)
ErrorOr<ByteBuffer> Filter::decode_crypt(ReadonlyBytes)
{
// FIXME: Support Crypt decoding
TODO();

23
Userland/Libraries/LibPDF/Filter.h
View file

@ -7,25 +7,26 @@
#pragma once
#include <AK/ByteBuffer.h>
#include <AK/Error.h>
#include <AK/FlyString.h>
namespace PDF {
class Filter {
public:
static Optional<ByteBuffer> decode(ReadonlyBytes bytes, FlyString const& encoding_type);
static ErrorOr<ByteBuffer> decode(ReadonlyBytes bytes, FlyString const& encoding_type);
private:
static Optional<ByteBuffer> decode_ascii_hex(ReadonlyBytes bytes);
static Optional<ByteBuffer> decode_ascii85(ReadonlyBytes bytes);
static Optional<ByteBuffer> decode_lzw(ReadonlyBytes bytes);
static Optional<ByteBuffer> decode_flate(ReadonlyBytes bytes);
static Optional<ByteBuffer> decode_run_length(ReadonlyBytes bytes);
static Optional<ByteBuffer> decode_ccitt(ReadonlyBytes bytes);
static Optional<ByteBuffer> decode_jbig2(ReadonlyBytes bytes);
static Optional<ByteBuffer> decode_dct(ReadonlyBytes bytes);
static Optional<ByteBuffer> decode_jpx(ReadonlyBytes bytes);
static Optional<ByteBuffer> decode_crypt(ReadonlyBytes bytes);
static ErrorOr<ByteBuffer> decode_ascii_hex(ReadonlyBytes bytes);
static ErrorOr<ByteBuffer> decode_ascii85(ReadonlyBytes bytes);
static ErrorOr<ByteBuffer> decode_lzw(ReadonlyBytes bytes);
static ErrorOr<ByteBuffer> decode_flate(ReadonlyBytes bytes);
static ErrorOr<ByteBuffer> decode_run_length(ReadonlyBytes bytes);
static ErrorOr<ByteBuffer> decode_ccitt(ReadonlyBytes bytes);
static ErrorOr<ByteBuffer> decode_jbig2(ReadonlyBytes bytes);
static ErrorOr<ByteBuffer> decode_dct(ReadonlyBytes bytes);
static ErrorOr<ByteBuffer> decode_jpx(ReadonlyBytes bytes);
static ErrorOr<ByteBuffer> decode_crypt(ReadonlyBytes bytes);
};
}

4
Userland/Libraries/LibPDF/Parser.cpp
View file

@ -1071,8 +1071,10 @@ RefPtr<StreamObject> Parser::parse_stream(NonnullRefPtr<DictObject> dict)
if (dict->contains(CommonNames::Filter)) {
auto filter_type = dict->get_name(m_document, CommonNames::Filter)->name();
auto maybe_bytes = Filter::decode(bytes, filter_type);
if (!maybe_bytes.has_value())
if (maybe_bytes.is_error()) {
warnln("Failed to decode filter: {}", maybe_bytes.error().string_literal());
return {};
}
return make_object<EncodedStreamObject>(dict, move(maybe_bytes.value()));
}