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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.
+ *
+ * $URL$
+ * $Id$
+ *
+ * Process scheduler.
+ */
+
+#include "tinsel/sched.h"
+
+#include "common/util.h"
+
+namespace Tinsel {
+
+Scheduler *g_scheduler = 0;
+
+/** process structure */
+struct PROCESS {
+ PROCESS *pNext; //!< pointer to next 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
+ int pid; //!< process ID
+ char param[PARAM_SIZE]; //!< process specific info
+};
+
+
+Scheduler::Scheduler() {
+ processList = 0;
+ pFreeProcesses = 0;
+ pCurrent = 0;
+
+#ifdef DEBUG
+ // diagnostic process counters
+ numProcs = 0;
+ maxProcs = 0;
+#endif
+
+ pRCfunction = 0;
+
+ active = new PROCESS;
+
+ g_scheduler = this; // FIXME HACK
+}
+
+Scheduler::~Scheduler() {
+ free(processList);
+ processList = NULL;
+
+ delete active;
+ active = 0;
+}
+
+/**
+ * Kills all processes and places them on the free list.
+ */
+void Scheduler::reset() {
+
+#ifdef DEBUG
+ // clear number of process in use
+ numProcs = 0;
+#endif
+
+ if (processList == NULL) {
+ // first time - allocate memory for process list
+ processList = (PROCESS *)calloc(NUM_PROCESS, sizeof(PROCESS));
+
+ // make sure memory allocated
+ if (processList == NULL) {
+ error("Cannot allocate memory for process data");
+ }
+
+ // fill with garbage
+ memset(processList, 'S', NUM_PROCESS * sizeof(PROCESS));
+ }
+
+ // no active processes
+ pCurrent = active->pNext = NULL;
+
+ // place first process on free list
+ pFreeProcesses = processList;
+
+ // link all other processes after first
+ for (int i = 1; i < NUM_PROCESS; i++) {
+ processList[i - 1].pNext = processList + i;
+ }
+
+ // null the last process
+ processList[NUM_PROCESS - 1].pNext = NULL;
+}
+
+
+#ifdef DEBUG
+/**
+ * Shows the maximum number of process used at once.
+ */
+void Scheduler::printStats(void) {
+ printf("%i process of %i used.\n", maxProcs, NUM_PROCESS);
+}
+#endif
+
+
+/**
+ * Give all active processes a chance to run
+ */
+void Scheduler::schedule(void) {
+ // start dispatching active process list
+ PROCESS *pPrevProc = active;
+ PROCESS *pProc = active->pNext;
+ while (pProc != NULL) {
+ if (--pProc->sleepTime <= 0) {
+ // process is ready for dispatch, activate it
+ pCurrent = pProc;
+ pProc->coroAddr(pProc->state, pProc->param);
+ pCurrent = NULL;
+ if (!pProc->state || pProc->state->_sleep <= 0) {
+ // Coroutine finished
+ killProcess(pProc);
+ pProc = pPrevProc;
+ } else {
+ pProc->sleepTime = pProc->state->_sleep;
+ }
+ }
+ pPrevProc = pProc;
+ pProc = pProc->pNext;
+ }
+}
+
+
+/**
+ * Creates a new process.
+ *
+ * @param pid process identifier
+ * @param CORO_ADDR coroutine start address
+ * @param pParam process specific info
+ * @param sizeParam size of process specific info
+ */
+PROCESS *Scheduler::createProcess(int pid, CORO_ADDR coroAddr, const void *pParam, int sizeParam) {
+ PROCESS *pProc;
+
+ // get a free process
+ pProc = pFreeProcesses;
+
+ // trap no free process
+ assert(pProc != NULL); // Out of processes
+
+#ifdef DEBUG
+ // one more process in use
+ if (++numProcs > maxProcs)
+ maxProcs = numProcs;
+#endif
+
+ // get link to next free process
+ pFreeProcesses = pProc->pNext;
+
+ if (pCurrent != NULL) {
+ // place new process before the next active process
+ pProc->pNext = pCurrent->pNext;
+
+ // make this new process the next active process
+ pCurrent->pNext = pProc;
+ } else { // no active processes, place process at head of list
+ pProc->pNext = active->pNext;
+ active->pNext = pProc;
+ }
+
+ // set coroutine entry point
+ pProc->coroAddr = coroAddr;
+
+ // clear coroutine state
+ pProc->state = 0;
+
+ // wake process up as soon as possible
+ pProc->sleepTime = 1;
+
+ // set new process id
+ pProc->pid = pid;
+
+ // set new process specific info
+ if (sizeParam) {
+ assert(sizeParam > 0 && sizeParam <= PARAM_SIZE);
+
+ // set new process specific info
+ memcpy(pProc->param, pParam, sizeParam);
+ }
+
+
+ // return created process
+ return pProc;
+}
+
+/**
+ * Kills the specified process.
+ *
+ * @param pKillProc which process to kill
+ */
+void Scheduler::killProcess(PROCESS *pKillProc) {
+ PROCESS *pProc, *pPrev; // process list pointers
+
+ // make sure a valid process pointer
+ assert(pKillProc >= processList && pKillProc <= processList + NUM_PROCESS - 1);
+
+ // can not kill the current process using killProcess !
+ assert(pCurrent != pKillProc);
+
+#ifdef DEBUG
+ // one less process in use
+ --numProcs;
+ assert(numProcs >= 0);
+#endif
+
+ // search the active list for the process
+ for (pProc = active->pNext, pPrev = active; pProc != NULL; pPrev = pProc, pProc = pProc->pNext) {
+ if (pProc == pKillProc) {
+ // found process in active list
+
+ // Free process' resources
+ if (pRCfunction != NULL)
+ (pRCfunction)(pProc);
+
+ delete pProc->state;
+
+ // make prev point to next to unlink pProc
+ pPrev->pNext = pProc->pNext;
+
+ // link first free process after pProc
+ pProc->pNext = pFreeProcesses;
+
+ // make pProc the first free process
+ pFreeProcesses = pProc;
+
+ return;
+ }
+ }
+
+ // process not found in active list if we get to here
+ error("killProcess(): tried to kill a process not in the list of active processes");
+}
+
+
+
+/**
+ * Returns a pointer to the currently running process.
+ */
+PROCESS *Scheduler::getCurrentProcess(void) {
+ return pCurrent;
+}
+
+/**
+ * Returns the process identifier of the specified process.
+ *
+ * @param pProc which process
+ */
+int Scheduler::getCurrentPID() const {
+ PROCESS *pProc = pCurrent;
+
+ // make sure a valid process pointer
+ assert(pProc >= processList && pProc <= processList + NUM_PROCESS - 1);
+
+ // return processes PID
+ return pProc->pid;
+}
+
+/**
+ * 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 Scheduler::killMatchingProcess(int pidKill, int pidMask) {
+ int numKilled = 0;
+ PROCESS *pProc, *pPrev; // process list pointers
+
+ for (pProc = active->pNext, pPrev = active; pProc != NULL; pPrev = pProc, pProc = pProc->pNext) {
+ if ((pProc->pid & pidMask) == pidKill) {
+ // found a matching process
+
+ // dont kill the current process
+ if (pProc != pCurrent) {
+ // kill this process
+ numKilled++;
+
+ // make prev point to next to unlink pProc
+ pPrev->pNext = pProc->pNext;
+
+ // link first free process after pProc
+ pProc->pNext = pFreeProcesses;
+
+ // make pProc the first free process
+ pFreeProcesses = pProc;
+
+ // set to a process on the active list
+ pProc = pPrev;
+ }
+ }
+ }
+
+#ifdef DEBUG
+ // adjust process in use
+ numProcs -= numKilled;
+ assert(numProcs >= 0);
+#endif
+
+ // return number of processes killed
+ return numKilled;
+}
+
+
+
+/**
+ * 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 Scheduler::setResourceCallback(VFPTRPP pFunc) {
+ pRCfunction = pFunc;
+}
+
+} // end of namespace Tinsel