ladybird/AK/Bitmap.h

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6.5 KiB
C
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/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/BitmapView.h>
#include <AK/Noncopyable.h>
#include <AK/Optional.h>
#include <AK/Platform.h>
#include <AK/StdLibExtras.h>
#include <AK/Types.h>
#include <AK/kmalloc.h>
namespace AK {
class Bitmap {
AK_MAKE_NONCOPYABLE(Bitmap);
public:
Bitmap() = default;
Bitmap(size_t size, bool default_value)
: m_size(size)
{
VERIFY(m_size != 0);
m_data = static_cast<u8*>(kmalloc(size_in_bytes()));
fill(default_value);
}
Bitmap(u8* data, size_t size, bool is_owning = false)
: m_data(data)
, m_size(size)
, m_is_owning(is_owning)
{
}
BitmapView view() { return { m_data, m_size }; }
const BitmapView view() const { return { m_data, m_size }; }
Bitmap(Bitmap&& other)
: m_data(exchange(other.m_data, nullptr))
, m_size(exchange(other.m_size, 0))
{
}
Bitmap& operator=(Bitmap&& other)
{
if (this != &other) {
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kfree_sized(m_data, size_in_bytes());
m_data = exchange(other.m_data, nullptr);
m_size = exchange(other.m_size, 0);
}
return *this;
}
~Bitmap()
{
if (m_is_owning) {
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kfree_sized(m_data, size_in_bytes());
}
m_data = nullptr;
}
size_t size() const { return m_size; }
size_t size_in_bytes() const { return ceil_div(m_size, static_cast<size_t>(8)); }
bool get(size_t index) const
{
VERIFY(index < m_size);
return 0 != (m_data[index / 8] & (1u << (index % 8)));
}
void set(size_t index, bool value) const
{
VERIFY(index < m_size);
if (value)
m_data[index / 8] |= static_cast<u8>((1u << (index % 8)));
else
m_data[index / 8] &= static_cast<u8>(~(1u << (index % 8)));
}
size_t count_slow(bool value) const { return count_in_range(0, m_size, value); }
size_t count_in_range(size_t start, size_t len, bool value) const { return view().count_in_range(start, len, value); }
bool is_null() const { return !m_data; }
u8* data() { return m_data; }
const u8* data() const { return m_data; }
void grow(size_t size, bool default_value)
{
VERIFY(size > m_size);
auto previous_size_bytes = size_in_bytes();
auto previous_size = m_size;
auto previous_data = m_data;
m_size = size;
m_data = reinterpret_cast<u8*>(kmalloc(size_in_bytes()));
fill(default_value);
if (previous_data != nullptr) {
__builtin_memcpy(m_data, previous_data, previous_size_bytes);
if (previous_size % 8)
set_range(previous_size, 8 - previous_size % 8, default_value);
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kfree_sized(previous_data, previous_size_bytes);
}
}
template<bool VALUE, bool verify_that_all_bits_flip = false>
void set_range(size_t start, size_t len)
{
VERIFY(start < m_size);
VERIFY(start + len <= m_size);
if (len == 0)
return;
u8* first = &m_data[start / 8];
u8* last = &m_data[(start + len) / 8];
u8 byte_mask = bitmask_first_byte[start % 8];
if (first == last) {
byte_mask &= bitmask_last_byte[(start + len) % 8];
if constexpr (verify_that_all_bits_flip) {
if constexpr (VALUE) {
VERIFY((*first & byte_mask) == 0);
} else {
VERIFY((*first & byte_mask) == byte_mask);
}
}
if constexpr (VALUE)
*first |= byte_mask;
else
*first &= ~byte_mask;
} else {
if constexpr (verify_that_all_bits_flip) {
if constexpr (VALUE) {
VERIFY((*first & byte_mask) == 0);
} else {
VERIFY((*first & byte_mask) == byte_mask);
}
}
if constexpr (VALUE)
*first |= byte_mask;
else
*first &= ~byte_mask;
byte_mask = bitmask_last_byte[(start + len) % 8];
if constexpr (verify_that_all_bits_flip) {
if constexpr (VALUE) {
VERIFY((*last & byte_mask) == 0);
} else {
VERIFY((*last & byte_mask) == byte_mask);
}
}
if constexpr (VALUE)
*last |= byte_mask;
else
*last &= ~byte_mask;
if (++first < last) {
if constexpr (VALUE)
__builtin_memset(first, 0xFF, last - first);
else
__builtin_memset(first, 0x0, last - first);
}
}
}
void set_range(size_t start, size_t len, bool value)
{
if (value)
set_range<true, false>(start, len);
else
set_range<false, false>(start, len);
}
void set_range_and_verify_that_all_bits_flip(size_t start, size_t len, bool value)
{
if (value)
set_range<true, true>(start, len);
else
set_range<false, true>(start, len);
}
void fill(bool value)
{
__builtin_memset(m_data, value ? 0xff : 0x00, size_in_bytes());
}
Optional<size_t> find_one_anywhere_set(size_t hint = 0) const { return view().find_one_anywhere<true>(hint); }
Optional<size_t> find_one_anywhere_unset(size_t hint = 0) const { return view().find_one_anywhere<false>(hint); }
Optional<size_t> find_first_set() const { return view().find_first<true>(); }
Optional<size_t> find_first_unset() const { return view().find_first<false>(); }
Optional<size_t> find_next_range_of_unset_bits(size_t& from, size_t min_length = 1, size_t max_length = max_size) const
{
return view().find_next_range_of_unset_bits(from, min_length, max_length);
}
Optional<size_t> find_longest_range_of_unset_bits(size_t max_length, size_t& found_range_size) const
{
return view().find_longest_range_of_unset_bits(max_length, found_range_size);
}
Optional<size_t> find_first_fit(size_t minimum_length) const { return view().find_first_fit(minimum_length); }
Optional<size_t> find_best_fit(size_t minimum_length) const { return view().find_best_fit(minimum_length); }
static constexpr size_t max_size = 0xffffffff;
private:
u8* m_data { nullptr };
size_t m_size { 0 };
bool m_is_owning { true };
};
}
using AK::Bitmap;