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godot/core/cowdata.h

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/*************************************************************************/
/* cowdata.h */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md). */
/* */
/* 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 <string.h>
#include "core/error_macros.h"
#include "core/os/memory.h"
#include "core/safe_refcount.h"
template <class T>
class Vector;
class String;
class CharString;
template <class T, class V>
class VMap;
template <class T>
class CowData {
template <class TV>
friend class Vector;
friend class String;
friend class CharString;
template <class TV, class VV>
friend class VMap;
private:
mutable T *_ptr;
// internal helpers
_FORCE_INLINE_ uint32_t *_get_refcount() const {
if (!_ptr)
return NULL;
return reinterpret_cast<uint32_t *>(_ptr) - 2;
}
_FORCE_INLINE_ uint32_t *_get_size() const {
if (!_ptr)
return NULL;
return reinterpret_cast<uint32_t *>(_ptr) - 1;
}
_FORCE_INLINE_ T *_get_data() const {
if (!_ptr)
return NULL;
return reinterpret_cast<T *>(_ptr);
}
_FORCE_INLINE_ size_t _get_alloc_size(size_t p_elements) const {
//return nearest_power_of_2_templated(p_elements*sizeof(T)+sizeof(SafeRefCount)+sizeof(int));
return next_power_of_2(p_elements * sizeof(T));
}
_FORCE_INLINE_ bool _get_alloc_size_checked(size_t p_elements, size_t *out) const {
#if defined(_add_overflow) && defined(_mul_overflow)
size_t o;
size_t p;
if (_mul_overflow(p_elements, sizeof(T), &o)) {
*out = 0;
return false;
}
*out = next_power_of_2(o);
if (_add_overflow(o, static_cast<size_t>(32), &p)) return false; //no longer allocated here
return true;
#else
// Speed is more important than correctness here, do the operations unchecked
// and hope the best
*out = _get_alloc_size(p_elements);
return true;
#endif
}
void _unref(void *p_data);
void _ref(const CowData *p_from);
void _ref(const CowData &p_from);
void _copy_on_write();
public:
void operator=(const CowData<T> &p_from) { _ref(p_from); }
_FORCE_INLINE_ T *ptrw() {
_copy_on_write();
return (T *)_get_data();
}
_FORCE_INLINE_ const T *ptr() const {
return _get_data();
}
_FORCE_INLINE_ int size() const {
uint32_t *size = (uint32_t *)_get_size();
if (size)
return *size;
else
return 0;
}
_FORCE_INLINE_ void clear() { resize(0); }
_FORCE_INLINE_ bool empty() const { return _ptr == 0; }
_FORCE_INLINE_ void set(int p_index, const T &p_elem) {
CRASH_BAD_INDEX(p_index, size());
_copy_on_write();
_get_data()[p_index] = p_elem;
}
_FORCE_INLINE_ T &get_m(int p_index) {
CRASH_BAD_INDEX(p_index, size());
_copy_on_write();
return _get_data()[p_index];
}
_FORCE_INLINE_ const T &get(int p_index) const {
CRASH_BAD_INDEX(p_index, size());
return _get_data()[p_index];
}
Error resize(int p_size);
_FORCE_INLINE_ void remove(int p_index) {
ERR_FAIL_INDEX(p_index, size());
T *p = ptrw();
int len = size();
for (int i = p_index; i < len - 1; i++) {
p[i] = p[i + 1];
};
resize(len - 1);
};
Error insert(int p_pos, const T &p_val) {
ERR_FAIL_INDEX_V(p_pos, size() + 1, ERR_INVALID_PARAMETER);
resize(size() + 1);
for (int i = (size() - 1); i > p_pos; i--)
set(i, get(i - 1));
set(p_pos, p_val);
return OK;
};
int find(const T &p_val, int p_from = 0) const;
_FORCE_INLINE_ CowData();
_FORCE_INLINE_ ~CowData();
_FORCE_INLINE_ CowData(CowData<T> &p_from) { _ref(p_from); };
};
template <class T>
void CowData<T>::_unref(void *p_data) {
if (!p_data)
return;
uint32_t *refc = _get_refcount();
if (atomic_decrement(refc) > 0)
return; // still in use
// clean up
if (!__has_trivial_destructor(T)) {
uint32_t *count = _get_size();
T *data = (T *)(count + 1);
for (uint32_t i = 0; i < *count; ++i) {
// call destructors
data[i].~T();
}
}
// free mem
Memory::free_static((uint8_t *)p_data, true);
}
template <class T>
void CowData<T>::_copy_on_write() {
if (!_ptr)
return;
uint32_t *refc = _get_refcount();
if (unlikely(*refc > 1)) {
/* in use by more than me */
uint32_t current_size = *_get_size();
uint32_t *mem_new = (uint32_t *)Memory::alloc_static(_get_alloc_size(current_size), true);
*(mem_new - 2) = 1; //refcount
*(mem_new - 1) = current_size; //size
T *_data = (T *)(mem_new);
// initialize new elements
if (__has_trivial_copy(T)) {
memcpy(mem_new, _ptr, current_size * sizeof(T));
} else {
for (uint32_t i = 0; i < current_size; i++) {
memnew_placement(&_data[i], T(_get_data()[i]));
}
}
_unref(_ptr);
_ptr = _data;
}
}
template <class T>
Error CowData<T>::resize(int p_size) {
ERR_FAIL_COND_V(p_size < 0, ERR_INVALID_PARAMETER);
if (p_size == size())
return OK;
if (p_size == 0) {
// wants to clean up
_unref(_ptr);
_ptr = NULL;
return OK;
}
// possibly changing size, copy on write
_copy_on_write();
size_t alloc_size;
ERR_FAIL_COND_V(!_get_alloc_size_checked(p_size, &alloc_size), ERR_OUT_OF_MEMORY);
if (p_size > size()) {
if (size() == 0) {
// alloc from scratch
uint32_t *ptr = (uint32_t *)Memory::alloc_static(alloc_size, true);
ERR_FAIL_COND_V(!ptr, ERR_OUT_OF_MEMORY);
*(ptr - 1) = 0; //size, currently none
*(ptr - 2) = 1; //refcount
_ptr = (T *)ptr;
} else {
void *_ptrnew = (T *)Memory::realloc_static(_ptr, alloc_size, true);
ERR_FAIL_COND_V(!_ptrnew, ERR_OUT_OF_MEMORY);
_ptr = (T *)(_ptrnew);
}
// construct the newly created elements
if (!__has_trivial_constructor(T)) {
T *elems = _get_data();
for (int i = *_get_size(); i < p_size; i++) {
memnew_placement(&elems[i], T);
}
}
*_get_size() = p_size;
} else if (p_size < size()) {
if (!__has_trivial_destructor(T)) {
// deinitialize no longer needed elements
for (uint32_t i = p_size; i < *_get_size(); i++) {
T *t = &_get_data()[i];
t->~T();
}
}
void *_ptrnew = (T *)Memory::realloc_static(_ptr, alloc_size, true);
ERR_FAIL_COND_V(!_ptrnew, ERR_OUT_OF_MEMORY);
_ptr = (T *)(_ptrnew);
*_get_size() = p_size;
}
return OK;
}
template <class T>
int CowData<T>::find(const T &p_val, int p_from) const {
int ret = -1;
if (p_from < 0 || size() == 0) {
return ret;
}
for (int i = p_from; i < size(); i++) {
if (get(i) == p_val) {
ret = i;
break;
}
}
return ret;
}
template <class T>
void CowData<T>::_ref(const CowData *p_from) {
_ref(*p_from);
}
template <class T>
void CowData<T>::_ref(const CowData &p_from) {
if (_ptr == p_from._ptr)
return; // self assign, do nothing.
_unref(_ptr);
_ptr = NULL;
if (!p_from._ptr)
return; //nothing to do
if (atomic_conditional_increment(p_from._get_refcount()) > 0) { // could reference
_ptr = p_from._ptr;
}
}
template <class T>
CowData<T>::CowData() {
_ptr = NULL;
}
template <class T>
CowData<T>::~CowData() {
_unref(_ptr);
}
#endif /* COW_H_ */
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