janwas
1861448e6c
also rename wchar -> utf8 to avoid conflict with <wchar.h> (requires rebuild of workspace) (unfortunately copying history fails to "502 bad gateway"; had to delete old + add new independently) This was SVN commit r7340.
91 lines
2.9 KiB
C++
91 lines
2.9 KiB
C++
/* Copyright (c) 2010 Wildfire Games
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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 included
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* 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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/*
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* helpers for module initialization/shutdown.
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*/
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#include "precompiled.h"
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#include "lib/module_init.h"
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#include "lib/sysdep/cpu.h" // cpu_CAS, cpu_AtomicAdd
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// notes:
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// - value must be 0 to allow users to just define uninitialized static
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// variables (they don't have access to our MODULE_* symbols)
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// - unlike expected in-game operation, the self-tests require repeated
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// sequences of init/shutdown pairs. we therefore allow this in general
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// (resetting back to MODULE_UNINITIALIZED after shutdown) because
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// there's no real disadvantage other than loss of strictness.
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static const ModuleInitState MODULE_UNINITIALIZED = 0u;
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// (1..N = reference count)
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static const ModuleInitState MODULE_ERROR = ~(uintptr_t)1u;
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bool ModuleShouldInitialize(volatile ModuleInitState* pInitState)
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{
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// currently uninitialized, so give the green light.
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if(cpu_CAS(pInitState, MODULE_UNINITIALIZED, 1))
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return true;
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// increment reference count - unless already in a final state.
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retry:
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ModuleInitState latchedInitState = *pInitState;
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if(latchedInitState == MODULE_ERROR)
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return false;
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if(!cpu_CAS(pInitState, latchedInitState, latchedInitState+1))
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goto retry;
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return false;
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}
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bool ModuleShouldShutdown(volatile ModuleInitState* pInitState)
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{
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// decrement reference count - unless already in a final state.
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retry:
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ModuleInitState latchedInitState = *pInitState;
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if(latchedInitState == MODULE_UNINITIALIZED || latchedInitState == MODULE_ERROR)
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return false;
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if(!cpu_CAS(pInitState, latchedInitState, latchedInitState-1))
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goto retry;
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// refcount reached zero => allow shutdown.
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if(latchedInitState-1 == MODULE_UNINITIALIZED)
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return true;
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return false;
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}
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void ModuleSetError(volatile ModuleInitState* pInitState)
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{
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*pInitState = MODULE_ERROR;
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}
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bool ModuleIsError(volatile ModuleInitState* pInitState)
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{
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return (*pInitState == MODULE_ERROR);
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}
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