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LibPDF: Use Core::Stream to parse the page offset hint table

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Tim Schumacher 2023-01-14 15:06:45 +01:00 committed by Linus Groh
parent f28b052590
commit b1bfeb391e
2 changed files with 25 additions and 20 deletions
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43
Userland/Libraries/LibPDF/DocumentParser.cpp
View file

@ -5,9 +5,10 @@
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/BitStream.h>
#include <AK/MemoryStream.h>
#include <AK/Tuple.h>
#include <LibCore/BitStream.h>
#include <LibCore/MemoryStream.h>
#include <LibPDF/CommonNames.h>
#include <LibPDF/Document.h>
#include <LibPDF/DocumentParser.h>
@ -251,7 +252,7 @@ PDFErrorOr<void> DocumentParser::initialize_hint_tables()
}
auto hint_table = TRY(parse_page_offset_hint_table(hint_stream_bytes));
auto hint_table_entries = parse_all_page_offset_hint_table_entries(hint_table, hint_stream_bytes);
auto hint_table_entries = TRY(parse_all_page_offset_hint_table_entries(hint_table, hint_stream_bytes));
// FIXME: Do something with the hint tables
return {};
@ -593,12 +594,12 @@ PDFErrorOr<DocumentParser::PageOffsetHintTable> DocumentParser::parse_page_offse
return hint_table;
}
Vector<DocumentParser::PageOffsetHintTableEntry> DocumentParser::parse_all_page_offset_hint_table_entries(PageOffsetHintTable const& hint_table, ReadonlyBytes hint_stream_bytes)
PDFErrorOr<Vector<DocumentParser::PageOffsetHintTableEntry>> DocumentParser::parse_all_page_offset_hint_table_entries(PageOffsetHintTable const& hint_table, ReadonlyBytes hint_stream_bytes)
{
InputMemoryStream input_stream(hint_stream_bytes);
input_stream.seek(sizeof(PageOffsetHintTable));
auto input_stream = TRY(Core::Stream::FixedMemoryStream::construct(hint_stream_bytes));
TRY(input_stream->seek(sizeof(PageOffsetHintTable)));
InputBitStream bit_stream(input_stream);
auto bit_stream = TRY(Core::Stream::LittleEndianInputBitStream::construct(move(input_stream)));
auto number_of_pages = m_linearization_dictionary.value().number_of_pages;
Vector<PageOffsetHintTableEntry> entries;
@ -613,19 +614,21 @@ Vector<DocumentParser::PageOffsetHintTableEntry> DocumentParser::parse_all_page_
auto bits_required_for_greatest_shared_obj_identifier = hint_table.bits_required_for_greatest_shared_obj_identifier;
auto bits_required_for_fraction_numerator = hint_table.bits_required_for_fraction_numerator;
auto parse_int_entry = [&](u32 PageOffsetHintTableEntry::*field, u32 bit_size) {
auto parse_int_entry = [&](u32 PageOffsetHintTableEntry::*field, u32 bit_size) -> ErrorOr<void> {
if (bit_size <= 0)
return;
return {};
for (int i = 0; i < number_of_pages; i++) {
auto& entry = entries[i];
entry.*field = bit_stream.read_bits(bit_size);
entry.*field = TRY(bit_stream->read_bits(bit_size));
}
return {};
};
auto parse_vector_entry = [&](Vector<u32> PageOffsetHintTableEntry::*field, u32 bit_size) {
auto parse_vector_entry = [&](Vector<u32> PageOffsetHintTableEntry::*field, u32 bit_size) -> ErrorOr<void> {
if (bit_size <= 0)
return;
return {};
for (int page = 1; page < number_of_pages; page++) {
auto number_of_shared_objects = entries[page].number_of_shared_objects;
@ -633,19 +636,21 @@ Vector<DocumentParser::PageOffsetHintTableEntry> DocumentParser::parse_all_page_
items.ensure_capacity(number_of_shared_objects);
for (size_t i = 0; i < number_of_shared_objects; i++)
items.unchecked_append(bit_stream.read_bits(bit_size));
items.unchecked_append(TRY(bit_stream->read_bits(bit_size)));
entries[page].*field = move(items);
}
return {};
};
parse_int_entry(&PageOffsetHintTableEntry::objects_in_page_number, bits_required_for_object_number);
parse_int_entry(&PageOffsetHintTableEntry::page_length_number, bits_required_for_page_length);
parse_int_entry(&PageOffsetHintTableEntry::number_of_shared_objects, bits_required_for_number_of_shared_obj_refs);
parse_vector_entry(&PageOffsetHintTableEntry::shared_object_identifiers, bits_required_for_greatest_shared_obj_identifier);
parse_vector_entry(&PageOffsetHintTableEntry::shared_object_location_numerators, bits_required_for_fraction_numerator);
parse_int_entry(&PageOffsetHintTableEntry::page_content_stream_offset_number, bits_required_for_content_stream_offsets);
parse_int_entry(&PageOffsetHintTableEntry::page_content_stream_length_number, bits_required_for_content_stream_length);
TRY(parse_int_entry(&PageOffsetHintTableEntry::objects_in_page_number, bits_required_for_object_number));
TRY(parse_int_entry(&PageOffsetHintTableEntry::page_length_number, bits_required_for_page_length));
TRY(parse_int_entry(&PageOffsetHintTableEntry::number_of_shared_objects, bits_required_for_number_of_shared_obj_refs));
TRY(parse_vector_entry(&PageOffsetHintTableEntry::shared_object_identifiers, bits_required_for_greatest_shared_obj_identifier));
TRY(parse_vector_entry(&PageOffsetHintTableEntry::shared_object_location_numerators, bits_required_for_fraction_numerator));
TRY(parse_int_entry(&PageOffsetHintTableEntry::page_content_stream_offset_number, bits_required_for_content_stream_offsets));
TRY(parse_int_entry(&PageOffsetHintTableEntry::page_content_stream_length_number, bits_required_for_content_stream_length));
return entries;
}

2
Userland/Libraries/LibPDF/DocumentParser.h
View file

@ -82,7 +82,7 @@ private:
PDFErrorOr<void> validate_xref_table_and_fix_if_necessary();
PDFErrorOr<void> initialize_hint_tables();
PDFErrorOr<PageOffsetHintTable> parse_page_offset_hint_table(ReadonlyBytes hint_stream_bytes);
Vector<PageOffsetHintTableEntry> parse_all_page_offset_hint_table_entries(PageOffsetHintTable const&, ReadonlyBytes hint_stream_bytes);
PDFErrorOr<Vector<PageOffsetHintTableEntry>> parse_all_page_offset_hint_table_entries(PageOffsetHintTable const&, ReadonlyBytes hint_stream_bytes);
PDFErrorOr<NonnullRefPtr<XRefTable>> parse_xref_stream();
PDFErrorOr<NonnullRefPtr<XRefTable>> parse_xref_table();
PDFErrorOr<NonnullRefPtr<DictObject>> parse_file_trailer();