/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#ifndef COMMON_COROUTINES_H
#define COMMON_COROUTINES_H
#include "common/scummsys.h"
#include "common/util.h" // for SCUMMVM_CURRENT_FUNCTION
#include "common/list.h"
#include "common/singleton.h"
namespace Common {
/**
* @defgroup Coroutine support for simulating multi-threading.
*
* The following is loosely based on an article by Simon Tatham:
* <http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html>.
* However, many improvements and tweaks have been made, in particular
* by taking advantage of C++ features not available in C.
*/
//@{
#define CoroScheduler (Common::CoroutineScheduler::instance())
// Enable this macro to enable some debugging support in the coroutine code.
//#define COROUTINE_DEBUG
/**
* The core of any coroutine context which captures the 'state' of a coroutine.
* Private use only.
*/
struct CoroBaseContext {
int _line;
int _sleep;
CoroBaseContext *_subctx;
#ifdef COROUTINE_DEBUG
const char *_funcName;
#endif
CoroBaseContext(const char *func);
virtual ~CoroBaseContext();
};
typedef CoroBaseContext *CoroContext;
/** This is a special constant that can be temporarily used as a parameter to call coroutine-ised
* from methods from methods that haven't yet been converted to being a coroutine, so code at least
* compiles correctly. Be aware, though, that if you use this, you will get runtime errors.
*/
extern CoroContext nullContext;
/**
* Wrapper class which holds a pointer to a pointer to a CoroBaseContext.
* The interesting part is the destructor, which kills the context being held,
* but ONLY if the _sleep val of that context is zero. This way, a coroutine
* can just 'return' w/o having to worry about freeing the allocated context
* (in Simon Tatham's original code, one had to use a special macro to
* return from a coroutine).
*/
class CoroContextHolder {
CoroContext &_ctx;
public:
CoroContextHolder(CoroContext &ctx) : _ctx(ctx) {
assert(ctx);
assert(ctx->_sleep >= 0);
ctx->_sleep = 0;
}
~CoroContextHolder() {
if (_ctx && _ctx->_sleep == 0) {
delete _ctx;
_ctx = 0;
}
}
};
/** Methods that have been converted to being a coroutine should have this as the first parameter */
#define CORO_PARAM Common::CoroContext &coroParam
/**
* Begin the declaration of a coroutine context.
* This allows declaring variables which are 'persistent' during the
* lifetime of the coroutine. An example use would be:
*
* CORO_BEGIN_CONTEXT;
* int var;
* char *foo;
* CORO_END_CONTEXT(_ctx);
*
* It is not possible to initialize variables here, due to the way this
* macro is implemented. Furthermore, to use the variables declared in
* the coroutine context, you have to access them via the context variable
* name that was specified as parameter to CORO_END_CONTEXT, e.g.
* _ctx->var = 0;
*
* @see CORO_END_CONTEXT
*
* @note We declare a variable 'DUMMY' to allow the user to specify an 'empty'
* context, and so compilers won't complain about ";" following the macro.
*/
#define CORO_BEGIN_CONTEXT \
struct CoroContextTag : Common::CoroBaseContext { \
CoroContextTag() : CoroBaseContext(SCUMMVM_CURRENT_FUNCTION) {} \
int DUMMY
/**
* End the declaration of a coroutine context.
* @param x name of the coroutine context
* @see CORO_BEGIN_CONTEXT
*/
#define CORO_END_CONTEXT(x) } *x = (CoroContextTag *)coroParam
/**
* Begin the code section of a coroutine.
* @param x name of the coroutine context
* @see CORO_BEGIN_CODE
*/
#define CORO_BEGIN_CODE(x) \
if (&coroParam == &Common::nullContext) assert(!Common::nullContext);\
if (!x) {coroParam = x = new CoroContextTag();}\
Common::CoroContextHolder tmpHolder(coroParam);\
switch (coroParam->_line) { case 0:;
/**
* End the code section of a coroutine.
* @see CORO_END_CODE
*/
#define CORO_END_CODE \
if (&coroParam == &Common::nullContext) { \
delete Common::nullContext; \
Common::nullContext = NULL; \
} \
}
/**
* Sleep for the specified number of scheduler cycles.
*/
#define CORO_SLEEP(delay) do {\
coroParam->_line = __LINE__;\
coroParam->_sleep = delay;\
assert(&coroParam != &Common::nullContext);\
return; case __LINE__:;\
} while (0)
#define CORO_GIVE_WAY do { CoroScheduler.giveWay(); CORO_SLEEP(1); } while (0)
#define CORO_RESCHEDULE do { CoroScheduler.reschedule(); CORO_SLEEP(1); } while (0)
/**
* Stop the currently running coroutine and all calling coroutines.
*
* This sets _sleep to -1 rather than 0 so that the context doesn't get
* deleted by CoroContextHolder, since we want CORO_INVOKE_ARGS to
* propogate the _sleep value and return immediately (the scheduler will
* then delete the entire coroutine's state, including all subcontexts).
*/
#define CORO_KILL_SELF() \
do { if (&coroParam != &Common::nullContext) { coroParam->_sleep = -1; } return; } while (0)
/**
* This macro is to be used in conjunction with CORO_INVOKE_ARGS and
* similar macros for calling coroutines-enabled subroutines.
*/
#define CORO_SUBCTX coroParam->_subctx
/**
* Invoke another coroutine.
*
* If the subcontext still exists after the coroutine is invoked, it has
* either yielded/slept or killed itself, and so we copy the _sleep value
* to our own context and return (execution will continue at the case
* statement below, where we loop and call the coroutine again).
* If the subcontext is null, the coroutine ended normally, and we can
* simply break out of the loop and continue execution.
*
* @param subCoro name of the coroutine-enabled function to invoke
* @param ARGS list of arguments to pass to subCoro
*
* @note ARGS must be surrounded by parentheses, and the first argument
* in this list must always be CORO_SUBCTX. For example, the
* regular function call
* myFunc(a, b);
* becomes the following:
* CORO_INVOKE_ARGS(myFunc, (CORO_SUBCTX, a, b));
*/
#define CORO_INVOKE_ARGS(subCoro, ARGS) \
do {\
coroParam->_line = __LINE__;\
coroParam->_subctx = 0;\
do {\
subCoro ARGS;\
if (!coroParam->_subctx) break;\
coroParam->_sleep = coroParam->_subctx->_sleep;\
assert(&coroParam != &Common::nullContext);\
return; case __LINE__:;\
} while (1);\
} while (0)
/**
* Invoke another coroutine. Similar to CORO_INVOKE_ARGS,
* but allows specifying a return value which is returned
* if invoked coroutine yields (thus causing the current
* coroutine to yield, too).
*/
#define CORO_INVOKE_ARGS_V(subCoro, RESULT, ARGS) \
do {\
coroParam->_line = __LINE__;\
coroParam->_subctx = 0;\
do {\
subCoro ARGS;\
if (!coroParam->_subctx) break;\
coroParam->_sleep = coroParam->_subctx->_sleep;\
assert(&coroParam != &Common::nullContext);\
return RESULT; case __LINE__:;\
} while (1);\
} while (0)
/**
* Convenience wrapper for CORO_INVOKE_ARGS for invoking a coroutine
* with no parameters.
*/
#define CORO_INVOKE_0(subCoroutine) \
CORO_INVOKE_ARGS(subCoroutine,(CORO_SUBCTX))
/**
* Convenience wrapper for CORO_INVOKE_ARGS for invoking a coroutine
* with one parameter.
*/
#define CORO_INVOKE_1(subCoroutine, a0) \
CORO_INVOKE_ARGS(subCoroutine,(CORO_SUBCTX,a0))
/**
* Convenience wrapper for CORO_INVOKE_ARGS for invoking a coroutine
* with two parameters.
*/
#define CORO_INVOKE_2(subCoroutine, a0,a1) \
CORO_INVOKE_ARGS(subCoroutine,(CORO_SUBCTX,a0,a1))
/**
* Convenience wrapper for CORO_INVOKE_ARGS for invoking a coroutine
* with three parameters.
*/
#define CORO_INVOKE_3(subCoroutine, a0,a1,a2) \
CORO_INVOKE_ARGS(subCoroutine,(CORO_SUBCTX,a0,a1,a2))
/**
* Convenience wrapper for CORO_INVOKE_ARGS for invoking a coroutine
* with four parameters.
*/
#define CORO_INVOKE_4(subCoroutine, a0,a1,a2,a3) \
CORO_INVOKE_ARGS(subCoroutine,(CORO_SUBCTX,a0,a1,a2,a3))
// the size of process specific info
#define CORO_PARAM_SIZE 32
// the maximum number of processes
#define CORO_NUM_PROCESS 100
#define CORO_MAX_PROCESSES 100
#define CORO_MAX_PID_WAITING 5
#define CORO_INFINITE 0xffffffff
#define CORO_INVALID_PID_VALUE 0
typedef void (*CORO_ADDR)(CoroContext &, const void *);
/** process structure */
struct PROCESS {
PROCESS *pNext; ///< pointer to next process in active or free list
PROCESS *pPrevious; ///< pointer to previous process in active or free list
CoroContext state; ///< the state of the coroutine
CORO_ADDR coroAddr; ///< the entry point of the coroutine
int sleepTime; ///< number of scheduler cycles to sleep
uint32 pid; ///< process ID
uint32 pidWaiting[CORO_MAX_PID_WAITING]; ///< Process ID(s) process is currently waiting on
char param[CORO_PARAM_SIZE]; ///< process specific info
};
typedef PROCESS *PPROCESS;
/** Event structure */
struct EVENT {
uint32 pid;
bool manualReset;
bool signalled;
bool pulsing;
};
/**
* Creates and manages "processes" (really coroutines).
*/
class CoroutineScheduler: public Singleton<CoroutineScheduler> {
public:
/** Pointer to a function of the form "void function(PPROCESS)" */
typedef void (*VFPTRPP)(PROCESS *);
private:
/** list of all processes */
PROCESS *processList;
/** active process list - also saves scheduler state */
PROCESS *active;
/** pointer to free process list */
PROCESS *pFreeProcesses;
/** the currently active process */
PROCESS *pCurrent;
/** Auto-incrementing process Id */
int pidCounter;
/** Event list */
Common::List<EVENT *> _events;
#ifdef DEBUG
// diagnostic process counters
int numProcs;
int maxProcs;
void CheckStack();
#endif
/**
* Called from killProcess() to enable other resources
* a process may be allocated to be released.
*/
VFPTRPP pRCfunction;
PROCESS *getProcess(uint32 pid);
EVENT *getEvent(uint32 pid);
public:
CoroutineScheduler();
~CoroutineScheduler();
void reset();
#ifdef DEBUG
void printStats();
#endif
void schedule();
void rescheduleAll();
void reschedule(PPROCESS pReSchedProc = NULL);
void giveWay(PPROCESS pReSchedProc = NULL);
void waitForSingleObject(CORO_PARAM, int pid, uint32 duration, bool *expired = NULL);
void waitForMultipleObjects(CORO_PARAM, int nCount, uint32 *pidList, bool bWaitAll,
uint32 duration, bool *expired = NULL);
void sleep(CORO_PARAM, uint32 duration);
PROCESS *createProcess(uint32 pid, CORO_ADDR coroAddr, const void *pParam, int sizeParam);
uint32 createProcess(CORO_ADDR coroAddr, const void *pParam, int sizeParam);
uint32 createProcess(CORO_ADDR coroAddr, const void *pParam);
void killProcess(PROCESS *pKillProc);
PROCESS *getCurrentProcess();
int getCurrentPID() const;
int killMatchingProcess(uint32 pidKill, int pidMask = -1);
void setResourceCallback(VFPTRPP pFunc);
/* Event methods */
uint32 createEvent(bool bManualReset, bool bInitialState);
void closeEvent(uint32 pidEvent);
void setEvent(uint32 pidEvent);
void resetEvent(uint32 pidEvent);
void pulseEvent(uint32 pidEvent);
};
//@}
} // end of namespace Common
#endif // COMMON_COROUTINES_H