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27637b9e7f
- Remove use of non-builtin overloaded `InterlockedExhangeSubtract()` for Windows. Moreover, it was wrongly being used as if it hadn't a 64-bit version instead of being overloaded. - Implement exchange-if-greater (as a CAS loop).
91 lines
3.6 KiB
C++
91 lines
3.6 KiB
C++
/*************************************************************************/
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/* safe_refcount.h */
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/*************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* http://www.godotengine.org */
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/*************************************************************************/
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/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur. */
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/* Copyright (c) 2014-2017 Godot Engine contributors (cf. AUTHORS.md) */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/*************************************************************************/
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#ifndef SAFE_REFCOUNT_H
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#define SAFE_REFCOUNT_H
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#include "os/mutex.h"
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/* x86/x86_64 GCC */
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#include "platform_config.h"
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#include "typedefs.h"
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uint32_t atomic_conditional_increment(register uint32_t *counter);
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uint32_t atomic_decrement(register uint32_t *pw);
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uint32_t atomic_increment(register uint32_t *pw);
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uint32_t atomic_sub(register uint32_t *pw, register uint32_t val);
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uint32_t atomic_add(register uint32_t *pw, register uint32_t val);
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uint32_t atomic_exchange_if_greater(register uint32_t *pw, register uint32_t val);
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uint64_t atomic_conditional_increment(register uint64_t *counter);
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uint64_t atomic_decrement(register uint64_t *pw);
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uint64_t atomic_increment(register uint64_t *pw);
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uint64_t atomic_sub(register uint64_t *pw, register uint64_t val);
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uint64_t atomic_add(register uint64_t *pw, register uint64_t val);
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uint64_t atomic_exchange_if_greater(register uint64_t *pw, register uint64_t val);
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struct SafeRefCount {
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uint32_t count;
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public:
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// destroy() is called when weak_count_ drops to zero.
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bool ref() { //true on success
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return atomic_conditional_increment(&count) != 0;
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}
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uint32_t refval() { //true on success
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return atomic_conditional_increment(&count);
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}
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bool unref() { // true if must be disposed of
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if (atomic_decrement(&count) == 0) {
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return true;
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}
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return false;
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}
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uint32_t get() const { // nothrow
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return count;
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}
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void init(uint32_t p_value = 1) {
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count = p_value;
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}
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};
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#endif
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