Diff: scheduler.cpp

Revision:

0:9ce7c170cb66

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scheduler.cpp	Fri Jun 11 20:52:03 2010 +0000
@@ -0,0 +1,126 @@
+/*! \file scheduler.c \brief Simple Task Scheduler. */
+//*****************************************************************************
+//
+// File Name    : 'scheduler.c'
+// Title        : Simple Task Scheduler
+// Author       : Pascal Stang - Copyright (C) 2006
+// Created      : 2006.05.24
+// Revised      : 2006.05.26
+// Version      : 0.1
+// Target MCU   : Atmel AVR Series
+// Editor Tabs  : 4
+//
+// NOTE: This code is currently below version 1.0, and therefore is considered
+// to be lacking in some functionality or documentation, or may not be fully
+// tested.  Nonetheless, you can expect most functions to work.
+//
+// This code is distributed under the GNU Public License
+//      which can be found at http://www.gnu.org/licenses/gpl.txt
+//
+//*****************************************************************************
+ 
+#include "scheduler.h"
+
+// the task list
+struct task TaskList[TASKLIST_SIZE];
+ 
+// functions
+void schedulerInit(void)
+{
+     int i;
+     
+     // reset task list
+     for(i=0; i<TASKLIST_SIZE; i++)
+     {
+         // initialize task list
+         TaskList[i].runtime = 0;
+         TaskList[i].funcptr = 0;
+     }
+ }
+ 
+void schedulerRun(int systime)
+{
+     int i;
+     
+     // locate active task slots
+     for(i=0; i<TASKLIST_SIZE; i++)
+     {
+         if(TaskList[i].funcptr)
+         {
+             // check systime against runtime
+             if(systime >= TaskList[i].runtime)
+             {
+                 // run task, then update it
+                 TaskList[i].funcptr(i,systime);
+                 
+                 if(TaskList[i].nrepeat)
+                 {
+                     TaskList[i].runtime += TaskList[i].interval;
+                     TaskList[i].nrepeat--;
+                     // task has expired, remove it now
+                     if(!TaskList[i].nrepeat)
+                         schedulerRemoveTask(i);
+                 }
+                 else
+                 {
+                     // nrepeat==0 means run forever
+                     TaskList[i].runtime += TaskList[i].interval;
+                 }
+                 
+             }
+         }
+     }
+ 
+     // increment scheduler timer
+     //SchedulerTimer++;
+}
+ 
+int schedulerAddTask(int runtime, int nrepeat, int interval, taskfuncptr taskfunc)
+{
+    int i;
+    
+    // locate empty scheduler slot
+    for(i=0; i<TASKLIST_SIZE; i++)
+    {
+        //CRITICAL_SECTION_BEGIN;
+        if(!TaskList[i].funcptr)
+        {
+            // setup entry
+            TaskList[i].funcptr = taskfunc;
+            TaskList[i].runtime = runtime;
+            TaskList[i].nrepeat = nrepeat;
+            TaskList[i].interval = interval;
+            
+            // return task handle
+            return i;
+        }
+        //CRITICAL_SECTION_END;
+    }
+    // error - no task slots left
+    return -1;
+}
+
+int schedulerRemoveTask(int taskhandle)
+{
+    // clear the task entry
+    TaskList[taskhandle].runtime = 0;
+    TaskList[taskhandle].interval = 0;
+    TaskList[taskhandle].nrepeat = 0;
+    TaskList[taskhandle].funcptr = 0;
+    
+    return taskhandle;
+}
+ 
+int schedulerRemoveTaskFunc(taskfuncptr funcptr)
+{
+    int i;
+    int taskhandle = -1;
+    
+    // locate the task
+    for(i=0; i<TASKLIST_SIZE; i++)
+    {
+        // on match, disable the task
+        if(TaskList[i].funcptr == funcptr) taskhandle = schedulerRemoveTask(i);
+    }
+    return taskhandle;
+}