BLT/include/blt/std/memory_util.h

476 lines
14 KiB
C++

/*
* <Short Description>
* Copyright (C) 2023 Brett Terpstra
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#ifndef BLT_MEMORY_UTIL_H
#define BLT_MEMORY_UTIL_H
#include <type_traits>
#include <array>
#include <string>
#include <cstring>
#include <algorithm>
#include <cstdint>
#include <climits>
#include <cmath>
#include <iostream>
#if defined(__clang__) || defined(__llvm__) || defined(__GNUC__) || defined(__GNUG__)
#if (defined(__GNUC__) || defined(__GNUG__)) && !defined(WIN32)
#include <byteswap.h>
#define SWAP16(val) bswap_16(val)
#define SWAP32(val) bswap_32(val)
#define SWAP64(val) bswap_64(val)
#else
#define SWAP16(val) __builtin_bswap16(val)
#define SWAP32(val) __builtin_bswap32(val)
#define SWAP64(val) __builtin_bswap64(val)
#endif
#if __cplusplus >= 202002L
#include <bit>
#define ENDIAN_LOOKUP(little_endian) (std::endian::native == std::endian::little && !little_endian) || \
(std::endian::native == std::endian::big && little_endian)
#else
#define ENDIAN_LOOKUP(little_endian) !little_endian
#endif
#elif defined(_MSC_VER)
#include <intrin.h>
#define SWAP16(val) _byteswap_ushort(val)
#define SWAP32(val) _byteswap_ulong(val)
#define SWAP64(val) _byteswap_uint64(val)
#define ENDIAN_LOOKUP(little_endian) !little_endian
#endif
namespace blt::mem
{
template <typename R, typename T>
static R type_cast(T type)
{
static_assert(std::is_trivially_copyable_v<T>, "Type must be trivially copyable to be type casted!");
static_assert(sizeof(T) == sizeof(R));
R r;
std::memcpy(&r, &type, sizeof(type));
return r;
}
template <typename T>
void reverse(T& out)
{
static_assert(std::is_trivially_copyable_v<T>, "Type must be trivially copyable to be reversible!");
// if we need to swap find the best way to do so
if constexpr (std::is_same_v<T, std::int16_t> || std::is_same_v<T, std::uint16_t>)
out = type_cast<T>(SWAP16(type_cast<std::uint16_t>(out)));
else if constexpr (std::is_same_v<T, std::int32_t> || std::is_same_v<T, std::uint32_t> || std::is_same_v<T, float>)
out = type_cast<T>(SWAP32(type_cast<std::uint32_t>(out)));
else if constexpr (std::is_same_v<T, std::int64_t> || std::is_same_v<T, std::uint64_t> || std::is_same_v<T, double>)
out = type_cast<T>(SWAP64(type_cast<std::uint64_t>(out)));
else
{
std::array<std::byte, sizeof(T)> data;
std::memcpy(data.data(), &out, sizeof(T));
std::reverse(data.begin(), data.end());
std::memcpy(&out, data.data(), sizeof(T));
}
}
// Used to grab the byte-data of any T element. Defaults to Big Endian, however can be configured to use little endian
template <bool little_endian = false, typename BYTE_TYPE, typename T>
int toBytes(const T& in, BYTE_TYPE* out)
{
if constexpr (!(std::is_same_v<BYTE_TYPE, std::int8_t> || std::is_same_v<BYTE_TYPE, std::uint8_t>))
static_assert("Must provide a signed/unsigned int8 type");
std::memcpy(out, &in, sizeof(T));
if constexpr (ENDIAN_LOOKUP(little_endian))
{
// TODO: this but better.
for (size_t i = 0; i < sizeof(T) / 2; i++)
std::swap(out[i], out[sizeof(T) - 1 - i]);
}
return 0;
}
// Used to cast the binary data of any T object, into a T object. Assumes data is in big ending (configurable)
template <bool little_endian = false, typename BYTE_TYPE, typename T>
int fromBytes(const BYTE_TYPE* in, T& out)
{
if constexpr (!(std::is_same_v<BYTE_TYPE, std::int8_t> || std::is_same_v<BYTE_TYPE, std::uint8_t>))
static_assert("Must provide a signed/unsigned int8 type");
std::memcpy(&out, in, sizeof(T));
if constexpr (ENDIAN_LOOKUP(little_endian))
{
reverse(out);
}
return 0;
}
template <bool little_endian = false, typename BYTE_TYPE, typename T>
static int fromBytes(const BYTE_TYPE* in, T* out)
{
return fromBytes<little_endian>(in, *out);
}
inline std::size_t next_byte_allocation(std::size_t prev_size, std::size_t default_allocation_block = 8192, std::size_t default_size = 16)
{
if (prev_size < default_size)
return default_size;
if (prev_size < default_allocation_block)
return prev_size * 2;
return prev_size + default_allocation_block;
}
template <bool bits = true, typename OStream, typename Value>
void print_bytes(OStream& stream, const Value& value)
{
constexpr auto size = sizeof(Value);
std::string line;
for (std::size_t i = 0; i < size; i++)
{
std::uint8_t byte;
std::memcpy(&byte, reinterpret_cast<const char*>(&value) + i, 1);
if constexpr (bits)
{
for (std::ptrdiff_t j = CHAR_BIT - 1; j >= 0; j--)
{
const auto bit = (byte >> j) & 1;
line += std::to_string(bit);
}
}
else
{
const auto byte_str = std::to_string(byte);
const auto amount = CHAR_BIT - byte_str.size();
for (std::size_t j = 0; j < static_cast<std::size_t>(std::ceil(static_cast<double>(amount) / 2.0)); j++)
line += ' ';
line += byte_str;
for (std::size_t j = 0; j < static_cast<std::size_t>(std::floor(static_cast<double>(amount) / 2.0)); j++)
line += ' ';
}
if (i != size - 1)
line += " : ";
}
for (std::size_t i = 0; i < size; i++)
{
auto index = std::to_string(i);
const auto amount = CHAR_BIT - index.size();
for (std::size_t j = 0; j < static_cast<std::size_t>(std::ceil(static_cast<double>(amount) / 2.0)); j++)
stream << ' ';
stream << index;
for (std::size_t j = 0; j < static_cast<std::size_t>(std::floor(static_cast<double>(amount) / 2.0)); j++)
stream << ' ';
if (i != size - 1)
stream << " | ";
}
stream << '\n';
stream << line;
stream << '\n';
}
// TODO: check if the platform actually has enough room in their pointers for this. plus endianness
struct bit_storage
{
static constexpr std::size_t START_BIT = 48;
static constexpr std::size_t END_BIT = sizeof(std::uintptr_t) * CHAR_BIT;
static constexpr std::size_t AVAILABLE_BITS = END_BIT - START_BIT;
static constexpr std::size_t make_storage_ones()
{
std::size_t result = 0;
for (std::size_t i = START_BIT; i < END_BIT; i++)
result |= 1ul << i;
return result;
}
static constexpr std::size_t make_ptr_ones()
{
std::size_t result = 0;
for (std::size_t i = 0; i < START_BIT; i++)
result |= 1ul << i;
return result;
}
bit_storage(): bits(0)
{
}
explicit bit_storage(const std::uint16_t bits): bits(bits)
{
}
std::uint16_t bits : AVAILABLE_BITS;
};
template <typename Ptr>
struct pointer_storage
{
static constexpr std::size_t STORAGE_ALL_ONES = bit_storage::make_storage_ones();
static constexpr std::size_t PTR_ALL_ONES = bit_storage::make_ptr_ones();
explicit pointer_storage(Ptr* ptr): ptr_bits(reinterpret_cast<std::uintptr_t>(ptr))
{
}
explicit pointer_storage(Ptr* ptr, const bit_storage bits): ptr_bits(reinterpret_cast<std::uintptr_t>(ptr))
{
storage(bits);
}
template <typename T, std::enable_if_t<!std::is_same_v<T, bit_storage>, bool> = false>
explicit pointer_storage(Ptr* ptr, const T& type): ptr_bits(reinterpret_cast<std::uintptr_t>(ptr))
{
storage(type);
}
[[nodiscard]] bit_storage storage() const noexcept
{
bit_storage storage{};
storage.bits = (ptr_bits & STORAGE_ALL_ONES) >> bit_storage::START_BIT;
return storage;
}
[[nodiscard]] bool bit(const std::size_t index) const noexcept
{
if (index >= bit_storage::END_BIT)
return false;
return (ptr_bits >> (bit_storage::START_BIT + index)) & 1;
}
pointer_storage& bit(const std::size_t index, const bool b) noexcept
{
if (index >= bit_storage::END_BIT)
return *this;
ptr_bits &= ~(1ul << (bit_storage::START_BIT + index));
ptr_bits |= (static_cast<std::uintptr_t>(b) << (bit_storage::START_BIT + index));
return *this;
}
template<typename T, std::enable_if_t<!std::is_same_v<T, bit_storage>, bool> = false>
pointer_storage& storage(const T& type)
{
static_assert(sizeof(T) <= sizeof(std::uintptr_t), "Type takes too many bits to be stored!");
static constexpr std::uintptr_t store_bits = (2 << (bit_storage::AVAILABLE_BITS - 1)) - 1;
std::uintptr_t bit_store = 0;
bit_storage store{};
std::memcpy(&bit_store, &type, sizeof(T));
store.bits |= bit_store & store_bits;
storage(store);
return *this;
}
pointer_storage& storage(const bit_storage bits) noexcept
{
ptr_bits = ((ptr_bits & PTR_ALL_ONES) | (static_cast<std::uintptr_t>(bits.bits) << bit_storage::START_BIT));
return *this;
}
pointer_storage& operator=(const bit_storage bits) noexcept
{
storage(bits);
return *this;
}
template<typename T, std::enable_if_t<!std::is_same_v<T, bit_storage>, bool> = false>
pointer_storage& operator=(const T& type)
{
storage(type);
return *this;
}
pointer_storage& clear_storage() noexcept
{
ptr_bits &= PTR_ALL_ONES;
return *this;
}
// changes pointer without changing the tag bits
pointer_storage& pointer(Ptr* ptr) noexcept
{
const bit_storage old_storage = storage();
ptr_bits = (reinterpret_cast<std::uintptr_t>(ptr) & PTR_ALL_ONES) | old_storage.bits;
return *this;
}
pointer_storage& operator=(Ptr* ptr) noexcept
{
pointer(ptr);
return *this;
}
pointer_storage& clear_pointer() noexcept
{
ptr_bits &= STORAGE_ALL_ONES;
return *this;
}
Ptr* get() const noexcept
{
return reinterpret_cast<Ptr*>(ptr_bits & PTR_ALL_ONES);
}
Ptr& operator*() const noexcept
{
return *get();
}
Ptr* operator->() const noexcept
{
return get();
}
private:
std::uintptr_t ptr_bits;
};
}
namespace blt
{
template <typename V>
struct ptr_iterator
{
using iterator_category = std::random_access_iterator_tag;
using difference_type = std::ptrdiff_t;
using value_type = V;
using pointer = value_type*;
using reference = value_type&;
using iter_reference = ptr_iterator&;
explicit ptr_iterator(V* v): _v(v)
{
}
reference operator*() const
{
return *_v;
}
pointer operator->()
{
return _v;
}
ptr_iterator& operator++()
{
_v++;
return *this;
}
ptr_iterator& operator--()
{
_v--;
return *this;
}
ptr_iterator operator++(int)
{
auto tmp = *this;
++(*this);
return tmp;
}
ptr_iterator operator--(int)
{
auto tmp = *this;
--(*this);
return tmp;
}
iter_reference operator+=(difference_type amount)
{
_v += amount;
return *this;
}
iter_reference operator-=(difference_type amount)
{
_v -= amount;
return *this;
}
reference operator[](difference_type index)
{
return *(_v + index);
}
reference operator[](std::size_t index)
{
return *(_v + index);
}
friend bool operator<(const ptr_iterator& a, const ptr_iterator& b)
{
return b._v - a._v > 0;
}
friend bool operator>(const ptr_iterator& a, const ptr_iterator& b)
{
return a._v - b._v > 0;
}
friend bool operator<=(const ptr_iterator& a, const ptr_iterator& b)
{
return b._v - a._v >= 0;
}
friend bool operator>=(const ptr_iterator& a, const ptr_iterator& b)
{
return a._v - b._v >= 0;
}
friend difference_type operator-(const ptr_iterator& a, const ptr_iterator& b)
{
return a._v - b._v;
}
friend ptr_iterator operator+(const ptr_iterator& a, difference_type n)
{
return ptr_iterator(a._v + n);
}
friend ptr_iterator operator+(difference_type n, const ptr_iterator& a)
{
return ptr_iterator(a._v + n);
}
friend bool operator==(const ptr_iterator& a, const ptr_iterator& b)
{
return a._v == b._v;
}
friend bool operator!=(const ptr_iterator& a, const ptr_iterator& b)
{
return a._v != b._v;
}
private:
V* _v;
};
}
#endif //BLT_MEMORY_UTIL_H