godot/core/templates/cowdata.h
2024-03-07 22:39:09 -06:00

485 lines
13 KiB
C++

/**************************************************************************/
/* cowdata.h */
/**************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/**************************************************************************/
#ifndef COWDATA_H
#define COWDATA_H
#include "core/error/error_macros.h"
#include "core/os/memory.h"
#include "core/templates/safe_refcount.h"
#include <string.h>
#include <type_traits>
template <typename T>
class Vector;
class String;
class Char16String;
class CharString;
template <typename T, typename V>
class VMap;
static_assert(std::is_trivially_destructible_v<std::atomic<uint64_t>>);
// Silence a false positive warning (see GH-52119).
#if defined(__GNUC__) && !defined(__clang__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wplacement-new"
#endif
template <typename T>
class CowData {
template <typename TV>
friend class Vector;
friend class String;
friend class Char16String;
friend class CharString;
template <typename TV, typename VV>
friend class VMap;
public:
typedef int64_t Size;
typedef uint64_t USize;
static constexpr USize MAX_INT = INT64_MAX;
private:
// Function to find the next power of 2 to an integer.
static _FORCE_INLINE_ USize next_po2(USize x) {
if (x == 0) {
return 0;
}
--x;
x |= x >> 1;
x |= x >> 2;
x |= x >> 4;
x |= x >> 8;
x |= x >> 16;
if (sizeof(USize) == 8) {
x |= x >> 32;
}
return ++x;
}
// Alignment: ↓ max_align_t ↓ USize ↓ max_align_t
// ┌────────────────────┬──┬─────────────┬──┬───────────...
// │ SafeNumeric<USize> │░░│ USize │░░│ T[]
// │ ref. count │░░│ data size │░░│ data
// └────────────────────┴──┴─────────────┴──┴───────────...
// Offset: ↑ REF_COUNT_OFFSET ↑ SIZE_OFFSET ↑ DATA_OFFSET
static constexpr size_t REF_COUNT_OFFSET = 0;
static constexpr size_t SIZE_OFFSET = ((REF_COUNT_OFFSET + sizeof(SafeNumeric<USize>)) % alignof(USize) == 0) ? (REF_COUNT_OFFSET + sizeof(SafeNumeric<USize>)) : ((REF_COUNT_OFFSET + sizeof(SafeNumeric<USize>)) + alignof(USize) - ((REF_COUNT_OFFSET + sizeof(SafeNumeric<USize>)) % alignof(USize)));
static constexpr size_t DATA_OFFSET = ((SIZE_OFFSET + sizeof(USize)) % alignof(max_align_t) == 0) ? (SIZE_OFFSET + sizeof(USize)) : ((SIZE_OFFSET + sizeof(USize)) + alignof(max_align_t) - ((SIZE_OFFSET + sizeof(USize)) % alignof(max_align_t)));
mutable T *_ptr = nullptr;
// internal helpers
static _FORCE_INLINE_ SafeNumeric<USize> *_get_refcount_ptr(uint8_t *p_ptr) {
return (SafeNumeric<USize> *)(p_ptr + REF_COUNT_OFFSET);
}
static _FORCE_INLINE_ USize *_get_size_ptr(uint8_t *p_ptr) {
return (USize *)(p_ptr + SIZE_OFFSET);
}
static _FORCE_INLINE_ T *_get_data_ptr(uint8_t *p_ptr) {
return (T *)(p_ptr + DATA_OFFSET);
}
_FORCE_INLINE_ SafeNumeric<USize> *_get_refcount() const {
if (!_ptr) {
return nullptr;
}
return (SafeNumeric<USize> *)((uint8_t *)_ptr - DATA_OFFSET + REF_COUNT_OFFSET);
}
_FORCE_INLINE_ USize *_get_size() const {
if (!_ptr) {
return nullptr;
}
return (USize *)((uint8_t *)_ptr - DATA_OFFSET + SIZE_OFFSET);
}
_FORCE_INLINE_ USize _get_alloc_size(USize p_elements) const {
return next_po2(p_elements * sizeof(T));
}
_FORCE_INLINE_ bool _get_alloc_size_checked(USize p_elements, USize *out) const {
if (unlikely(p_elements == 0)) {
*out = 0;
return true;
}
#if defined(__GNUC__) && defined(IS_32_BIT)
USize o;
USize p;
if (__builtin_mul_overflow(p_elements, sizeof(T), &o)) {
*out = 0;
return false;
}
*out = next_po2(o);
if (__builtin_add_overflow(o, static_cast<USize>(32), &p)) {
return false; // No longer allocated here.
}
#else
// Speed is more important than correctness here, do the operations unchecked
// and hope for the best.
*out = _get_alloc_size(p_elements);
#endif
return *out;
}
void _unref(void *p_data);
void _ref(const CowData *p_from);
void _ref(const CowData &p_from);
USize _copy_on_write();
public:
void operator=(const CowData<T> &p_from) { _ref(p_from); }
_FORCE_INLINE_ T *ptrw() {
_copy_on_write();
return _ptr;
}
_FORCE_INLINE_ const T *ptr() const {
return _ptr;
}
_FORCE_INLINE_ Size size() const {
USize *size = (USize *)_get_size();
if (size) {
return *size;
} else {
return 0;
}
}
_FORCE_INLINE_ void clear() { resize(0); }
_FORCE_INLINE_ bool is_empty() const { return _ptr == nullptr; }
_FORCE_INLINE_ void set(Size p_index, const T &p_elem) {
ERR_FAIL_INDEX(p_index, size());
_copy_on_write();
_ptr[p_index] = p_elem;
}
_FORCE_INLINE_ T &get_m(Size p_index) {
CRASH_BAD_INDEX(p_index, size());
_copy_on_write();
return _ptr[p_index];
}
_FORCE_INLINE_ const T &get(Size p_index) const {
CRASH_BAD_INDEX(p_index, size());
return _ptr[p_index];
}
template <bool p_ensure_zero = false>
Error resize(Size p_size);
_FORCE_INLINE_ void remove_at(Size p_index) {
ERR_FAIL_INDEX(p_index, size());
T *p = ptrw();
Size len = size();
for (Size i = p_index; i < len - 1; i++) {
p[i] = p[i + 1];
}
resize(len - 1);
}
Error insert(Size p_pos, const T &p_val) {
ERR_FAIL_INDEX_V(p_pos, size() + 1, ERR_INVALID_PARAMETER);
resize(size() + 1);
for (Size i = (size() - 1); i > p_pos; i--) {
set(i, get(i - 1));
}
set(p_pos, p_val);
return OK;
}
Size find(const T &p_val, Size p_from = 0) const;
Size rfind(const T &p_val, Size p_from = -1) const;
Size count(const T &p_val) const;
_FORCE_INLINE_ CowData() {}
_FORCE_INLINE_ ~CowData();
_FORCE_INLINE_ CowData(CowData<T> &p_from) { _ref(p_from); };
};
template <typename T>
void CowData<T>::_unref(void *p_data) {
if (!p_data) {
return;
}
SafeNumeric<USize> *refc = _get_refcount();
if (refc->decrement() > 0) {
return; // still in use
}
// clean up
if constexpr (!std::is_trivially_destructible_v<T>) {
USize *count = _get_size();
T *data = (T *)(count + 1);
for (USize i = 0; i < *count; ++i) {
// call destructors
data[i].~T();
}
}
// free mem
Memory::free_static(((uint8_t *)p_data) - DATA_OFFSET, false);
}
template <typename T>
typename CowData<T>::USize CowData<T>::_copy_on_write() {
if (!_ptr) {
return 0;
}
SafeNumeric<USize> *refc = _get_refcount();
USize rc = refc->get();
if (unlikely(rc > 1)) {
/* in use by more than me */
USize current_size = *_get_size();
uint8_t *mem_new = (uint8_t *)Memory::alloc_static(_get_alloc_size(current_size) + DATA_OFFSET, false);
ERR_FAIL_NULL_V(mem_new, 0);
SafeNumeric<USize> *_refc_ptr = _get_refcount_ptr(mem_new);
USize *_size_ptr = _get_size_ptr(mem_new);
T *_data_ptr = _get_data_ptr(mem_new);
new (_refc_ptr) SafeNumeric<USize>(1); //refcount
*(_size_ptr) = current_size; //size
// initialize new elements
if constexpr (std::is_trivially_copyable_v<T>) {
memcpy((uint8_t *)_data_ptr, _ptr, current_size * sizeof(T));
} else {
for (USize i = 0; i < current_size; i++) {
memnew_placement(&_data_ptr[i], T(_ptr[i]));
}
}
_unref(_ptr);
_ptr = _data_ptr;
rc = 1;
}
return rc;
}
template <typename T>
template <bool p_ensure_zero>
Error CowData<T>::resize(Size p_size) {
ERR_FAIL_COND_V(p_size < 0, ERR_INVALID_PARAMETER);
Size current_size = size();
if (p_size == current_size) {
return OK;
}
if (p_size == 0) {
// wants to clean up
_unref(_ptr);
_ptr = nullptr;
return OK;
}
// possibly changing size, copy on write
USize rc = _copy_on_write();
USize current_alloc_size = _get_alloc_size(current_size);
USize alloc_size;
ERR_FAIL_COND_V(!_get_alloc_size_checked(p_size, &alloc_size), ERR_OUT_OF_MEMORY);
if (p_size > current_size) {
if (alloc_size != current_alloc_size) {
if (current_size == 0) {
// alloc from scratch
uint8_t *mem_new = (uint8_t *)Memory::alloc_static(alloc_size + DATA_OFFSET, false);
ERR_FAIL_NULL_V(mem_new, ERR_OUT_OF_MEMORY);
SafeNumeric<USize> *_refc_ptr = _get_refcount_ptr(mem_new);
USize *_size_ptr = _get_size_ptr(mem_new);
T *_data_ptr = _get_data_ptr(mem_new);
new (_refc_ptr) SafeNumeric<USize>(1); //refcount
*(_size_ptr) = 0; //size, currently none
_ptr = _data_ptr;
} else {
uint8_t *mem_new = (uint8_t *)Memory::realloc_static(((uint8_t *)_ptr) - DATA_OFFSET, alloc_size + DATA_OFFSET, false);
ERR_FAIL_NULL_V(mem_new, ERR_OUT_OF_MEMORY);
SafeNumeric<USize> *_refc_ptr = _get_refcount_ptr(mem_new);
T *_data_ptr = _get_data_ptr(mem_new);
new (_refc_ptr) SafeNumeric<USize>(rc); //refcount
_ptr = _data_ptr;
}
}
// construct the newly created elements
if constexpr (!std::is_trivially_constructible_v<T>) {
for (Size i = *_get_size(); i < p_size; i++) {
memnew_placement(&_ptr[i], T);
}
} else if (p_ensure_zero) {
memset((void *)(_ptr + current_size), 0, (p_size - current_size) * sizeof(T));
}
*_get_size() = p_size;
} else if (p_size < current_size) {
if constexpr (!std::is_trivially_destructible_v<T>) {
// deinitialize no longer needed elements
for (USize i = p_size; i < *_get_size(); i++) {
T *t = &_ptr[i];
t->~T();
}
}
if (alloc_size != current_alloc_size) {
uint8_t *mem_new = (uint8_t *)Memory::realloc_static(((uint8_t *)_ptr) - DATA_OFFSET, alloc_size + DATA_OFFSET, false);
ERR_FAIL_NULL_V(mem_new, ERR_OUT_OF_MEMORY);
SafeNumeric<USize> *_refc_ptr = _get_refcount_ptr(mem_new);
T *_data_ptr = _get_data_ptr(mem_new);
new (_refc_ptr) SafeNumeric<USize>(rc); //refcount
_ptr = _data_ptr;
}
*_get_size() = p_size;
}
return OK;
}
template <typename T>
typename CowData<T>::Size CowData<T>::find(const T &p_val, Size p_from) const {
Size ret = -1;
if (p_from < 0 || size() == 0) {
return ret;
}
for (Size i = p_from; i < size(); i++) {
if (get(i) == p_val) {
ret = i;
break;
}
}
return ret;
}
template <typename T>
typename CowData<T>::Size CowData<T>::rfind(const T &p_val, Size p_from) const {
const Size s = size();
if (p_from < 0) {
p_from = s + p_from;
}
if (p_from < 0 || p_from >= s) {
p_from = s - 1;
}
for (Size i = p_from; i >= 0; i--) {
if (get(i) == p_val) {
return i;
}
}
return -1;
}
template <typename T>
typename CowData<T>::Size CowData<T>::count(const T &p_val) const {
Size amount = 0;
for (Size i = 0; i < size(); i++) {
if (get(i) == p_val) {
amount++;
}
}
return amount;
}
template <typename T>
void CowData<T>::_ref(const CowData *p_from) {
_ref(*p_from);
}
template <typename T>
void CowData<T>::_ref(const CowData &p_from) {
if (_ptr == p_from._ptr) {
return; // self assign, do nothing.
}
_unref(_ptr);
_ptr = nullptr;
if (!p_from._ptr) {
return; //nothing to do
}
if (p_from._get_refcount()->conditional_increment() > 0) { // could reference
_ptr = p_from._ptr;
}
}
template <typename T>
CowData<T>::~CowData() {
_unref(_ptr);
}
#if defined(__GNUC__) && !defined(__clang__)
#pragma GCC diagnostic pop
#endif
#endif // COWDATA_H