jcs.org
Serenity Operating System
1/*
2 * Copyright (c) 2021, Matthew Olsson <mattco@serenityos.org>
3 * Copyright (c) 2021, Ben Wiederhake <BenWiederhake.GitHub@gmx.de>
4 *
5 * SPDX-License-Identifier: BSD-2-Clause
6 */
7
8#pragma once
9
10#include <AK/Types.h>
11
12namespace PDF {
13
14class Reference {
15 // We store refs as u32, with 18 bits for the index and 14 bits for the
16 // generation index. The generation index is stored in the higher bits.
17 // This may need to be rethought later, as the max generation index is
18 // 2^16 and the max for the object index is probably 2^32 (I don't know
19 // exactly)
20 static constexpr auto MAX_REF_INDEX = (1 << 19) - 1; // 2 ^ 19 - 1
21 static constexpr auto MAX_REF_GENERATION_INDEX = (1 << 15) - 1; // 2 ^ 15 - 1
22
23public:
24 Reference(u32 index, u32 generation_index)
25 {
26 VERIFY(index < MAX_REF_INDEX);
27 VERIFY(generation_index < MAX_REF_GENERATION_INDEX);
28 m_combined = (generation_index << 14) | index;
29 }
30
31 [[nodiscard]] ALWAYS_INLINE u32 as_ref_index() const
32 {
33 return m_combined & 0x3ffff;
34 }
35
36 [[nodiscard]] ALWAYS_INLINE u32 as_ref_generation_index() const
37 {
38 return m_combined >> 18;
39 }
40
41private:
42 u32 m_combined;
43};
44
45}