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/*
* Copyright (c) 2021, Matthew Olsson <mattco@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/NonnullRefPtrVector.h>
#include <AK/WeakPtr.h>
#include <LibPDF/Command.h>
#include <LibPDF/Object.h>
#include <LibPDF/Reader.h>
#include <LibPDF/XRefTable.h>
namespace PDF {
class Document;
class Parser final : public RefCounted<Parser> {
public:
enum class LinearizationResult {
Error,
NotLinearized,
Linearized,
};
static Vector<Command> parse_graphics_commands(ReadonlyBytes);
Parser(Badge<Document>, ReadonlyBytes);
[[nodiscard]] ALWAYS_INLINE RefPtr<DictObject> const& trailer() const { return m_trailer; }
void set_document(WeakPtr<Document> const&);
// Parses the header and initializes the xref table and trailer
bool initialize();
Value parse_object_with_index(u32 index);
// Specialized version of parse_dict which aborts early if the dict being parsed
// is not a page object. A null RefPtr return indicates that the dict at this index
// is not a page tree node, whereas ok == false indicates a malformed PDF file and
// should cause an abort of the current operation.
RefPtr<DictObject> conditionally_parse_page_tree_node(u32 object_index, bool& ok);
private:
struct LinearizationDictionary {
u32 length_of_file { 0 };
u32 primary_hint_stream_offset { 0 };
u32 primary_hint_stream_length { 0 };
u32 overflow_hint_stream_offset { 0 };
u32 overflow_hint_stream_length { 0 };
u32 first_page_object_number { 0 };
u32 offset_of_first_page_end { 0 };
u16 number_of_pages { 0 };
u32 offset_of_main_xref_table { 0 };
u32 first_page { 0 }; // The page to initially open (I think, the spec isn't all that clear here)
};
struct PageOffsetHintTable {
u32 least_number_of_objects_in_a_page { 0 };
u32 location_of_first_page_object { 0 };
u16 bits_required_for_object_number { 0 };
u32 least_length_of_a_page { 0 };
u16 bits_required_for_page_length { 0 };
u32 least_offset_of_any_content_stream { 0 };
u16 bits_required_for_content_stream_offsets { 0 };
u32 least_content_stream_length { 0 };
u16 bits_required_for_content_stream_length { 0 };
u16 bits_required_for_number_of_shared_obj_refs { 0 };
u16 bits_required_for_greatest_shared_obj_identifier { 0 };
u16 bits_required_for_fraction_numerator { 0 };
u16 shared_object_reference_fraction_denominator { 0 };
};
struct PageOffsetHintTableEntry {
u32 objects_in_page_number { 0 };
u32 page_length_number { 0 };
u32 number_of_shared_objects { 0 };
Vector<u32> shared_object_identifiers {};
Vector<u32> shared_object_location_numerators {};
u32 page_content_stream_offset_number { 0 };
u32 page_content_stream_length_number { 0 };
};
friend struct AK::Formatter<LinearizationDictionary>;
friend struct AK::Formatter<PageOffsetHintTable>;
friend struct AK::Formatter<PageOffsetHintTableEntry>;
explicit Parser(ReadonlyBytes);
bool parse_header();
LinearizationResult initialize_linearization_dict();
bool initialize_linearized_xref_table();
bool initialize_non_linearized_xref_table();
bool initialize_hint_tables();
Optional<PageOffsetHintTable> parse_page_offset_hint_table(ReadonlyBytes hint_stream_bytes);
Optional<Vector<PageOffsetHintTableEntry>> parse_all_page_offset_hint_table_entries(PageOffsetHintTable const&, ReadonlyBytes hint_stream_bytes);
RefPtr<XRefTable> parse_xref_table();
RefPtr<DictObject> parse_file_trailer();
bool navigate_to_before_eof_marker();
bool navigate_to_after_startxref();
// If the PDF is linearized, the first object will be the linearization
// parameter dictionary, and it will always occur within the first 1024 bytes.
// We do a very sloppy and context-free search for this object. A return value
// of true does not necessarily mean this PDF is linearized, but a return value
// of false does mean this PDF is not linearized.
// FIXME: false doesn't guarantee non-linearization, but we VERIFY the result!
bool sloppy_is_linearized();
String parse_comment();
Value parse_value();
Value parse_possible_indirect_value_or_ref();
RefPtr<IndirectValue> parse_indirect_value(int index, int generation);
RefPtr<IndirectValue> parse_indirect_value();
Value parse_number();
RefPtr<NameObject> parse_name();
RefPtr<StringObject> parse_string();
String parse_literal_string();
String parse_hex_string();
RefPtr<ArrayObject> parse_array();
RefPtr<DictObject> parse_dict();
RefPtr<StreamObject> parse_stream(NonnullRefPtr<DictObject> dict);
Vector<Command> parse_graphics_commands();
bool matches_eol() const;
bool matches_whitespace() const;
bool matches_number() const;
bool matches_delimiter() const;
bool matches_regular_character() const;
bool consume_eol();
bool consume_whitespace();
char consume();
void consume(int amount);
bool consume(char);
Reader m_reader;
WeakPtr<Document> m_document;
RefPtr<XRefTable> m_xref_table;
RefPtr<DictObject> m_trailer;
Optional<LinearizationDictionary> m_linearization_dictionary;
};
};
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