mirror of
https://github.com/godotengine/godot.git
synced 2024-11-27 09:16:35 +08:00
158c3fbf3c
Differences with this aren't huge but the effort is minimal, in some workloads gain a couple of percent of performance.
284 lines
8.6 KiB
C++
284 lines
8.6 KiB
C++
/*************************************************************************/
|
|
/* safe_refcount.h */
|
|
/*************************************************************************/
|
|
/* This file is part of: */
|
|
/* GODOT ENGINE */
|
|
/* https://godotengine.org */
|
|
/*************************************************************************/
|
|
/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur. */
|
|
/* Copyright (c) 2014-2017 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 SAFE_REFCOUNT_H
|
|
#define SAFE_REFCOUNT_H
|
|
|
|
#include "os/mutex.h"
|
|
/* x86/x86_64 GCC */
|
|
|
|
#include "platform_config.h"
|
|
#include "typedefs.h"
|
|
|
|
// Atomic functions, these are used for multithread safe reference counters!
|
|
|
|
#ifdef NO_THREADS
|
|
|
|
/* Bogus implementation unaware of multiprocessing */
|
|
|
|
template <class T>
|
|
static _ALWAYS_INLINE_ T atomic_conditional_increment(register T *pw) {
|
|
|
|
if (*pw == 0)
|
|
return 0;
|
|
|
|
(*pw)++;
|
|
|
|
return *pw;
|
|
}
|
|
|
|
template <class T>
|
|
static _ALWAYS_INLINE_ T atomic_decrement(register T *pw) {
|
|
|
|
(*pw)--;
|
|
|
|
return *pw;
|
|
}
|
|
|
|
template <class T>
|
|
static _ALWAYS_INLINE_ T atomic_increment(register T *pw) {
|
|
|
|
(*pw)++;
|
|
|
|
return *pw;
|
|
}
|
|
|
|
template <class T, class V>
|
|
static _ALWAYS_INLINE_ T atomic_sub(register T *pw, register V val) {
|
|
|
|
(*pw) -= val;
|
|
|
|
return *pw;
|
|
}
|
|
|
|
template <class T, class V>
|
|
static _ALWAYS_INLINE_ T atomic_add(register T *pw, register V val) {
|
|
|
|
(*pw) += val;
|
|
|
|
return *pw;
|
|
}
|
|
|
|
template <class T, class V>
|
|
static _ALWAYS_INLINE_ T atomic_exchange_if_greater(register T *pw, register V val) {
|
|
|
|
if (val > *pw)
|
|
*pw = val;
|
|
|
|
return *pw;
|
|
}
|
|
|
|
#elif defined(__GNUC__)
|
|
|
|
/* Implementation for GCC & Clang */
|
|
|
|
// GCC guarantees atomic intrinsics for sizes of 1, 2, 4 and 8 bytes.
|
|
// Clang states it supports GCC atomic builtins.
|
|
|
|
template <class T>
|
|
static _ALWAYS_INLINE_ T atomic_conditional_increment(register T *pw) {
|
|
|
|
while (true) {
|
|
T tmp = static_cast<T const volatile &>(*pw);
|
|
if (tmp == 0)
|
|
return 0; // if zero, can't add to it anymore
|
|
if (__sync_val_compare_and_swap(pw, tmp, tmp + 1) == tmp)
|
|
return tmp + 1;
|
|
}
|
|
}
|
|
|
|
template <class T>
|
|
static _ALWAYS_INLINE_ T atomic_decrement(register T *pw) {
|
|
|
|
return __sync_sub_and_fetch(pw, 1);
|
|
}
|
|
|
|
template <class T>
|
|
static _ALWAYS_INLINE_ T atomic_increment(register T *pw) {
|
|
|
|
return __sync_add_and_fetch(pw, 1);
|
|
}
|
|
|
|
template <class T, class V>
|
|
static _ALWAYS_INLINE_ T atomic_sub(register T *pw, register V val) {
|
|
|
|
return __sync_sub_and_fetch(pw, val);
|
|
}
|
|
|
|
template <class T, class V>
|
|
static _ALWAYS_INLINE_ T atomic_add(register T *pw, register V val) {
|
|
|
|
return __sync_add_and_fetch(pw, val);
|
|
}
|
|
|
|
template <class T, class V>
|
|
static _ALWAYS_INLINE_ T atomic_exchange_if_greater(register T *pw, register V val) {
|
|
|
|
while (true) {
|
|
T tmp = static_cast<T const volatile &>(*pw);
|
|
if (tmp >= val)
|
|
return tmp; // already greater, or equal
|
|
if (__sync_val_compare_and_swap(pw, tmp, val) == tmp)
|
|
return val;
|
|
}
|
|
}
|
|
|
|
#elif defined(_MSC_VER)
|
|
|
|
/* Implementation for MSVC-Windows */
|
|
|
|
// don't pollute my namespace!
|
|
#include <windows.h>
|
|
|
|
#define ATOMIC_CONDITIONAL_INCREMENT_BODY(m_pw, m_win_type, m_win_cmpxchg, m_cpp_type) \
|
|
/* try to increment until it actually works */ \
|
|
/* taken from boost */ \
|
|
while (true) { \
|
|
m_cpp_type tmp = static_cast<m_cpp_type const volatile &>(*(m_pw)); \
|
|
if (tmp == 0) \
|
|
return 0; /* if zero, can't add to it anymore */ \
|
|
if (m_win_cmpxchg((m_win_type volatile *)(m_pw), tmp + 1, tmp) == tmp) \
|
|
return tmp + 1; \
|
|
}
|
|
|
|
#define ATOMIC_EXCHANGE_IF_GREATER_BODY(m_pw, m_val, m_win_type, m_win_cmpxchg, m_cpp_type) \
|
|
while (true) { \
|
|
m_cpp_type tmp = static_cast<m_cpp_type const volatile &>(*(m_pw)); \
|
|
if (tmp >= m_val) \
|
|
return tmp; /* already greater, or equal */ \
|
|
if (m_win_cmpxchg((m_win_type volatile *)(m_pw), m_val, tmp) == tmp) \
|
|
return m_val; \
|
|
}
|
|
|
|
static _ALWAYS_INLINE_ uint32_t atomic_conditional_increment(register uint32_t *pw) {
|
|
|
|
ATOMIC_CONDITIONAL_INCREMENT_BODY(pw, LONG, InterlockedCompareExchange, uint32_t)
|
|
}
|
|
|
|
static _ALWAYS_INLINE_ uint32_t atomic_decrement(register uint32_t *pw) {
|
|
|
|
return InterlockedDecrement((LONG volatile *)pw);
|
|
}
|
|
|
|
static _ALWAYS_INLINE_ uint32_t atomic_increment(register uint32_t *pw) {
|
|
|
|
return InterlockedIncrement((LONG volatile *)pw);
|
|
}
|
|
|
|
static _ALWAYS_INLINE_ uint32_t atomic_sub(register uint32_t *pw, register uint32_t val) {
|
|
|
|
return InterlockedExchangeAdd((LONG volatile *)pw, -(int32_t)val) - val;
|
|
}
|
|
|
|
static _ALWAYS_INLINE_ uint32_t atomic_add(register uint32_t *pw, register uint32_t val) {
|
|
|
|
return InterlockedAdd((LONG volatile *)pw, val);
|
|
}
|
|
|
|
static _ALWAYS_INLINE_ uint32_t atomic_exchange_if_greater(register uint32_t *pw, register uint32_t val) {
|
|
|
|
ATOMIC_EXCHANGE_IF_GREATER_BODY(pw, val, LONG, InterlockedCompareExchange, uint32_t)
|
|
}
|
|
|
|
static _ALWAYS_INLINE_ uint64_t atomic_conditional_increment(register uint64_t *pw) {
|
|
|
|
ATOMIC_CONDITIONAL_INCREMENT_BODY(pw, LONGLONG, InterlockedCompareExchange64, uint64_t)
|
|
}
|
|
|
|
static _ALWAYS_INLINE_ uint64_t atomic_decrement(register uint64_t *pw) {
|
|
|
|
return InterlockedDecrement64((LONGLONG volatile *)pw);
|
|
}
|
|
|
|
static _ALWAYS_INLINE_ uint64_t atomic_increment(register uint64_t *pw) {
|
|
|
|
return InterlockedIncrement64((LONGLONG volatile *)pw);
|
|
}
|
|
|
|
static _ALWAYS_INLINE_ uint64_t atomic_sub(register uint64_t *pw, register uint64_t val) {
|
|
|
|
return InterlockedExchangeAdd64((LONGLONG volatile *)pw, -(int64_t)val) - val;
|
|
}
|
|
|
|
static _ALWAYS_INLINE_ uint64_t atomic_add(register uint64_t *pw, register uint64_t val) {
|
|
|
|
return InterlockedAdd64((LONGLONG volatile *)pw, val);
|
|
}
|
|
|
|
static _ALWAYS_INLINE_ uint64_t atomic_exchange_if_greater(register uint64_t *pw, register uint64_t val) {
|
|
|
|
ATOMIC_EXCHANGE_IF_GREATER_BODY(pw, val, LONGLONG, InterlockedCompareExchange64, uint64_t)
|
|
}
|
|
|
|
#else
|
|
|
|
//no threads supported?
|
|
#error Must provide atomic functions for this platform or compiler!
|
|
|
|
#endif
|
|
|
|
struct SafeRefCount {
|
|
|
|
uint32_t count;
|
|
|
|
public:
|
|
// destroy() is called when weak_count_ drops to zero.
|
|
|
|
_ALWAYS_INLINE_ bool ref() { //true on success
|
|
|
|
return atomic_conditional_increment(&count) != 0;
|
|
}
|
|
|
|
_ALWAYS_INLINE_ uint32_t refval() { //true on success
|
|
|
|
return atomic_conditional_increment(&count);
|
|
}
|
|
|
|
_ALWAYS_INLINE_ bool unref() { // true if must be disposed of
|
|
|
|
if (atomic_decrement(&count) == 0) {
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
_ALWAYS_INLINE_ uint32_t get() const { // nothrow
|
|
|
|
return count;
|
|
}
|
|
|
|
_ALWAYS_INLINE_ void init(uint32_t p_value = 1) {
|
|
|
|
count = p_value;
|
|
}
|
|
};
|
|
|
|
#endif
|