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/*
* Copyright (c) 2021, Matthew Olsson <mattco@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Format.h>
#include <AK/RefCounted.h>
#include <AK/String.h>
#include <AK/Vector.h>
namespace PDF {
constexpr long invalid_byte_offset = NumericLimits<long>::max();
struct XRefEntry {
long byte_offset { invalid_byte_offset };
u16 generation_number { 0 };
bool in_use { false };
};
struct XRefSection {
int starting_index;
int count;
Vector<XRefEntry> entries;
};
class XRefTable final : public RefCounted<XRefTable> {
public:
bool merge(XRefTable&& other)
{
auto this_size = m_entries.size();
auto other_size = other.m_entries.size();
m_entries.ensure_capacity(other_size);
for (size_t i = 0; i < other_size; i++) {
auto other_entry = other.m_entries[i];
if (i >= this_size) {
m_entries.unchecked_append(other_entry);
continue;
}
auto this_entry = m_entries[i];
if (this_entry.byte_offset == invalid_byte_offset) {
m_entries[i] = other_entry;
} else if (other_entry.byte_offset != invalid_byte_offset) {
// Both xref tables have an entry for the same object index
return false;
}
}
return true;
}
void add_section(XRefSection const& section)
{
m_entries.ensure_capacity(section.starting_index + section.count);
for (int i = static_cast<int>(m_entries.size()); i < section.starting_index; i++)
m_entries.append(XRefEntry {});
for (auto& entry : section.entries)
m_entries.append(entry);
}
[[nodiscard]] ALWAYS_INLINE bool has_object(size_t index) const
{
return index < m_entries.size() && m_entries[index].byte_offset != -1;
}
[[nodiscard]] ALWAYS_INLINE long byte_offset_for_object(size_t index) const
{
VERIFY(has_object(index));
return m_entries[index].byte_offset;
}
[[nodiscard]] ALWAYS_INLINE u16 generation_number_for_object(size_t index) const
{
VERIFY(has_object(index));
return m_entries[index].generation_number;
}
[[nodiscard]] ALWAYS_INLINE bool is_object_in_use(size_t index) const
{
VERIFY(has_object(index));
return m_entries[index].in_use;
}
private:
friend struct AK::Formatter<PDF::XRefTable>;
Vector<XRefEntry> m_entries;
};
}
namespace AK {
template<>
struct Formatter<PDF::XRefEntry> : Formatter<StringView> {
ErrorOr<void> format(FormatBuilder& builder, PDF::XRefEntry const& entry)
{
return Formatter<StringView>::format(builder,
String::formatted("XRefEntry {{ offset={} generation={} used={} }}",
entry.byte_offset,
entry.generation_number,
entry.in_use));
}
};
template<>
struct Formatter<PDF::XRefTable> : Formatter<StringView> {
ErrorOr<void> format(FormatBuilder& format_builder, PDF::XRefTable const& table)
{
StringBuilder builder;
builder.append("XRefTable {");
for (auto& entry : table.m_entries)
builder.appendff("\n {}", entry);
builder.append("\n}");
return Formatter<StringView>::format(format_builder, builder.to_string());
}
};
}
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