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- /*
- File: SomeTasks.cp
-
- Contains: Some Multi Processing Tasks and utility functions.
-
- Version: 1.0
-
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- Software may be incorporated.
-
- The Apple Software is provided by Apple on an "AS IS" basis. APPLE MAKES NO
- WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED
- WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN
- COMBINATION WITH YOUR PRODUCTS.
-
- IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR
- CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
- GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION, MODIFICATION AND/OR DISTRIBUTION
- OF THE APPLE SOFTWARE, HOWEVER CAUSED AND WHETHER UNDER THEORY OF CONTRACT, TORT
- (INCLUDING NEGLIGENCE), STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN
- ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
- Copyright © 2003 Apple Computer, Inc., All Rights Reserved
- */
-
- #include "SomeTasks.h"
- #include "HIObjectThreadController.h"
-
- /*****************************************************
- *
- * SendEventToUI(kind, params, iterator, result)
- *
- * Purpose: Posts an event to the main thread which is handling the User Interface
- *
- * Inputs: kind - the kind of event (in this sample code: kEventUpdateThreadUI or kEventTerminateThread)
- * params - a pointer to the task params
- * iterator - the current value of the iteration index
- * result - the current value of the variable being calculated, in this sample code: pi
- *
- */
- void SendEventToUI(UInt32 kind, GeneralTaskWorkParamsPtr params, double iterator, double result)
- {
- params->iterator = iterator;
- params->result = result;
-
- EventRef theEvent;
- CreateEvent(NULL, kEventClassHIObjectThreadController, kind, GetCurrentEventTime(), kEventAttributeUserEvent, &theEvent);
- SetEventParameter(theEvent, kEventParamPostTarget, typeEventTargetRef, sizeof(params->threadControllerTarget), ¶ms->threadControllerTarget);
- PostEventToQueue(GetMainEventQueue(), theEvent, kEventPriorityStandard);
-
- ReleaseEvent(theEvent);
- }
-
- // pi = 4 ( 1 - 1/3 + 1/5 - 1/7 + 1/9 - ...)
- OSStatus CalculatingPiUsingLeibnizSimpleTask(void *p)
- {
- LeibnizTaskWorkParamsPtr params = (LeibnizTaskWorkParamsPtr)p;
- Boolean sign = params->sign;
- double denominator = params->general.iterator;
- double result = params->general.result;
-
- double lastDenominator = denominator + kSTEndIteration;
- double lastUIChange = denominator + kSTUIIteration;
-
- Duration updateInterval = 200 * durationMillisecond;
- AbsoluteTime nextTime = AddDurationToAbsolute(updateInterval, UpTime());
-
- for (; denominator < lastDenominator; )
- {
- if (sign)
- result += 4.0/denominator;
- else
- result -= 4.0/denominator;
- sign = ! sign;
- denominator += 2.0;
-
- // we don't want to submerge the main thread with too many events
- // so we check first if it's a good time to send one.
- // we also don't want to call too many APIs checking so we first
- // test if we did enough iterations.
- if (denominator > lastUIChange)
- {
- lastUIChange = denominator + kSTUIIteration;
-
- AbsoluteTime newTime = UpTime();
- if (S64Compare(UnsignedWideToUInt64(nextTime), UnsignedWideToUInt64(newTime)) < 0)
- {
- SendEventToUI(kEventUpdateThreadUI, (GeneralTaskWorkParamsPtr)params, denominator, result);
- nextTime = AddDurationToAbsolute(updateInterval, newTime);
- }
- }
- }
-
- // iteration is finished, we send the appropriate event to the main thread.
- SendEventToUI(kEventTerminateThread, (GeneralTaskWorkParamsPtr)params, denominator, result);
-
- return noErr;
- }
-
- void * SetUpLeibniz(void)
- {
- LeibnizTaskWorkParamsPtr params = (LeibnizTaskWorkParamsPtr)malloc(sizeof(LeibnizTaskWorkParams));
- params->sign = true;
- params->general.iterator = 1.0;
- params->general.result = 0.0;
- return params;
- }
-
- void TermLeibniz(void * p)
- {
- free(p);
- }
-
- // pi = 2 ( (2/1) * (2/3) * (4/3) * (4/5) * (6/5) * (6/7) * (...) )
- OSStatus CalculatingPiUsingWallisSimpleTask(void *p)
- {
- WallisTaskWorkParamsPtr params = (WallisTaskWorkParamsPtr)p;
- double numerator = params->general.iterator;
- double denominator = params->denominator;
- double result = params->general.result;
-
- double lastNumerator = numerator + kSTEndIteration;
- double lastUIChange = numerator + kSTUIIteration;
-
- AbsoluteTime interval, newTime, lastTime = UpTime();
-
- for (; numerator < lastNumerator; )
- {
- result *= numerator;
- result /= denominator;
- denominator += 2.0;
- result *= numerator;
- result /= denominator;
- numerator += 2.0;
-
- // we don't want to submerge the main thread with too many events
- // so we check first if it's a good time to send one.
- // we also don't want to call too many APIs checking so we first
- // test if we did enough iterations.
- if (numerator > lastUIChange)
- {
- lastUIChange = numerator + kSTUIIteration;
-
- newTime = UpTime();
- interval = SubAbsoluteFromAbsolute(newTime, lastTime);
- Duration duration = AbsoluteToDuration(interval) / -1000;
- if (duration > 200)
- {
- lastTime = newTime;
- SendEventToUI(kEventUpdateThreadUI, (GeneralTaskWorkParamsPtr)params, numerator, result);
- }
- }
- }
-
- // iteration is finished, we send the appropriate event to the main thread.
- SendEventToUI(kEventTerminateThread, (GeneralTaskWorkParamsPtr)params, numerator, result);
-
- return noErr;
- }
-
- void * SetUpWallis(void)
- {
- WallisTaskWorkParamsPtr params = (WallisTaskWorkParamsPtr)malloc(sizeof(WallisTaskWorkParams));
- params->general.iterator = 2.0;
- params->denominator = 1.0;
- params->general.result = 2.0;
- return params;
- }
-
- void TermWallis(void * p)
- {
- free(p);
- }
-