117 lines
3.8 KiB
C++
117 lines
3.8 KiB
C++
/*************************************************************************/
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/* safe_refcount.cpp */
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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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#include "safe_refcount.h"
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// Atomic functions, these are used for multithread safe reference counters!
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#ifdef NO_THREADS
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uint32_t atomic_conditional_increment(register uint32_t *pw) {
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if (*pw == 0)
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return 0;
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(*pw)++;
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return *pw;
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}
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uint32_t atomic_increment(register uint32_t *pw) {
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(*pw)++;
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return *pw;
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}
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uint32_t atomic_decrement(register uint32_t *pw) {
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(*pw)--;
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return *pw;
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}
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#else
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#ifdef _MSC_VER
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// don't pollute my namespace!
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#include <windows.h>
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uint32_t atomic_conditional_increment(register uint32_t *pw) {
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/* try to increment until it actually works */
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// taken from boost
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while (true) {
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uint32_t tmp = static_cast<uint32_t const volatile &>(*pw);
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if (tmp == 0)
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return 0; // if zero, can't add to it anymore
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if (InterlockedCompareExchange((LONG volatile *)pw, tmp + 1, tmp) == tmp)
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return tmp + 1;
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}
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}
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uint32_t atomic_decrement(register uint32_t *pw) {
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return InterlockedDecrement((LONG volatile *)pw);
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}
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uint32_t atomic_increment(register uint32_t *pw) {
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return InterlockedIncrement((LONG volatile *)pw);
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}
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#elif defined(__GNUC__)
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uint32_t atomic_conditional_increment(register uint32_t *pw) {
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while (true) {
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uint32_t tmp = static_cast<uint32_t const volatile &>(*pw);
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if (tmp == 0)
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return 0; // if zero, can't add to it anymore
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if (__sync_val_compare_and_swap(pw, tmp, tmp + 1) == tmp)
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return tmp + 1;
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}
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}
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uint32_t atomic_decrement(register uint32_t *pw) {
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return __sync_sub_and_fetch(pw, 1);
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}
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uint32_t atomic_increment(register uint32_t *pw) {
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return __sync_add_and_fetch(pw, 1);
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}
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#else
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//no threads supported?
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#error Must provide atomic functions for this platform or compiler!
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#endif
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#endif
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