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+/* 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
+ /**
+ * Creates a coroutine context
+ */
+ CoroBaseContext(const char *func);
+
+ /**
+ * Destructor for coroutine context
+ */
+ virtual ~CoroBaseContext();
+};
+
+typedef CoroBaseContext *CoroContext;
+
+
+/** This is a special constant that can be temporarily used as a parameter to call coroutine-ised
+ * methods from code that haven't yet been converted to being a coroutine, so code at least
+ * compiles correctly. Be aware, though, that an error will occur if a coroutine that was passed
+ * the nullContext tries to sleep or yield control.
+ */
+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
+
+/** Coroutine parameter for methods converted to coroutines */
+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:
+ friend class Singleton<CoroutineScheduler>;
+
+ /**
+ * Constructor
+ */
+ CoroutineScheduler();
+
+ /**
+ * Destructor
+ */
+ ~CoroutineScheduler();
+
+
+ /** 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;
+
+ /**
+ * Checks both the active and free process list to insure all the links are valid,
+ * and that no processes have been lost
+ */
+ 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:
+ /**
+ * Kills all processes and places them on the free list.
+ */
+ void reset();
+
+#ifdef DEBUG
+ /**
+ * Shows the maximum number of process used at once.
+ */
+ void printStats();
+#endif
+
+ /**
+ * Give all active processes a chance to run
+ */
+ void schedule();
+
+ /**
+ * Reschedules all the processes to run again this tick
+ */
+ void rescheduleAll();
+
+ /**
+ * If the specified process has already run on this tick, make it run
+ * again on the current tick.
+ */
+ void reschedule(PPROCESS pReSchedProc = NULL);
+
+ /**
+ * Moves the specified process to the end of the dispatch queue
+ * allowing it to run again within the current game cycle.
+ * @param pGiveProc Which process
+ */
+ void giveWay(PPROCESS pReSchedProc = NULL);
+
+ /**
+ * Continously makes a given process wait for another process to finish or event to signal.
+ *
+ * @param pid Process/Event identifier
+ * @param duration Duration in milliseconds
+ * @param expired If specified, set to true if delay period expired
+ */
+ void waitForSingleObject(CORO_PARAM, int pid, uint32 duration, bool *expired = NULL);
+
+ /**
+ * Continously makes a given process wait for given prcesses to finished or events to be set
+ *
+ * @param nCount Number of Id's being passed
+ * @param evtList List of pids to wait for
+ * @param bWaitAll Specifies whether all or any of the processes/events
+ * @param duration Duration in milliseconds
+ * @param expired Set to true if delay period expired
+ */
+ void waitForMultipleObjects(CORO_PARAM, int nCount, uint32 *pidList, bool bWaitAll,
+ uint32 duration, bool *expired = NULL);
+
+ /**
+ * Make the active process sleep for the given duration in milliseconds
+ *
+ * @param duration Duration in milliseconds
+ * @remarks This duration won't be precise, since it relies on the frequency the
+ * scheduler is called.
+ */
+ void sleep(CORO_PARAM, uint32 duration);
+
+ /**
+ * Creates a new process.
+ *
+ * @param pid process identifier
+ * @param coroAddr Coroutine start address
+ * @param pParam Process specific info
+ * @param sizeParam Size of process specific info
+ */
+ PROCESS *createProcess(uint32 pid, CORO_ADDR coroAddr, const void *pParam, int sizeParam);
+
+ /**
+ * Creates a new process with an auto-incrementing Process Id.
+ *
+ * @param coroAddr Coroutine start address
+ * @param pParam Process specific info
+ * @param sizeParam Size of process specific info
+ */
+ uint32 createProcess(CORO_ADDR coroAddr, const void *pParam, int sizeParam);
+
+ /**
+ * Creates a new process with an auto-incrementing Process Id, and a single pointer parameter.
+ *
+ * @param coroAddr Coroutine start address
+ * @param pParam Process specific info
+ */
+ uint32 createProcess(CORO_ADDR coroAddr, const void *pParam);
+
+ /**
+ * Kills the specified process.
+ *
+ * @param pKillProc Which process to kill
+ */
+ void killProcess(PROCESS *pKillProc);
+
+ /**
+ * Returns a pointer to the currently running process.
+ */
+ PROCESS *getCurrentProcess();
+
+ /**
+ * Returns the process identifier of the currently running process.
+ */
+ int getCurrentPID() const;
+
+ /**
+ * Kills any process matching the specified PID. The current
+ * process cannot be killed.
+ *
+ * @param pidKill Process identifier of process to kill
+ * @param pidMask Mask to apply to process identifiers before comparison
+ * @return The number of processes killed is returned.
+ */
+ int killMatchingProcess(uint32 pidKill, int pidMask = -1);
+
+ /**
+ * Set pointer to a function to be called by killProcess().
+ *
+ * May be called by a resource allocator, the function supplied is
+ * called by killProcess() to allow the resource allocator to free
+ * resources allocated to the dying process.
+ *
+ * @param pFunc Function to be called by killProcess()
+ */
+ void setResourceCallback(VFPTRPP pFunc);
+
+ /* Event methods */
+ /**
+ * Creates a new event (semaphore) object
+ *
+ * @param bManualReset Events needs to be manually reset. Otherwise,
+ * events will be automatically reset after a
+ * process waits on the event finishes
+ * @param bInitialState Specifies whether the event is signalled or not
+ * initially
+ */
+ uint32 createEvent(bool bManualReset, bool bInitialState);
+
+ /**
+ * Destroys the given event
+ * @param pidEvent Event Process Id
+ */
+ void closeEvent(uint32 pidEvent);
+
+ /**
+ * Sets the event
+ * @param pidEvent Event Process Id
+ */
+ void setEvent(uint32 pidEvent);
+
+ /**
+ * Resets the event
+ * @param pidEvent Event Process Id
+ */
+ void resetEvent(uint32 pidEvent);
+
+ /**
+ * Temporarily sets a given event to true, and then runs all waiting
+ * processes,allowing any processes waiting on the event to be fired. It
+ * then immediately resets the event again.
+ *
+ * @param pidEvent Event Process Id
+ *
+ * @remarks Should not be run inside of another process
+ */
+ void pulseEvent(uint32 pidEvent);
+};
+
+//@}
+
+} // end of namespace Common
+
+#endif // COMMON_COROUTINES_H
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