Developer CD Series 1998 January: Mac OS SDK/Dev.CD Jan 98 SDK2.toast/Development Kits (Disc 2)/QuickTime/Programming Stuff/Documentation/develop articles/develop Issue 13/Inside QuickTime and Components/Capture Component/Capture Component Code/NuMathComponent.c

Text File | 1997-02-26 | 8.7 KB | 328 lines | [TEXT/KAHL]

/*
    File:        NuMathComponent.c

    Contains:    NuMath component routines.

    Written by:    Gary Woodcock

    Copyright:    © 1992 by Apple Computer, Inc., all rights reserved.

    Change History (most recent first):

*/

//-----------------------------------------------------------------------
// Includes

#include "MathComponent.h"
#include "MathComponentPrivate.h"
#include "NuMathComponentPrivate.h"
#include <FixMath.h>

//-----------------------------------------------------------------------

#ifdef DEBUG_IT

// Use this declaration when we're running linked (for debugging)
pascal    ComponentResult    NuMathDispatcher    (ComponentParameters    *params,
                                             Handle                    storage)

#else

// Use this declaration when we're a standalone component
pascal    ComponentResult    main    (ComponentParameters    *params,
                                 Handle                    storage)

#endif DEBUG_IT

{
    // This routine is the main dispatcher for the NuMath component

    ComponentResult    result = noErr;
    PrivateGlobals**    globals=(PrivateGlobals**)storage;

    // Did we get a Component Manager request code (< 0)?
    if (params->what < 0)
    {
        switch (params->what)
        {
            case kComponentOpenSelect:        // Open request
            {
                result = CallComponentFunctionWithStorage (storage, params,
                    (ComponentFunction) _NuMathOpen);
                break;
            }
            case kComponentCloseSelect:        // Close request
            {
                result = CallComponentFunctionWithStorage (storage, params,
                    (ComponentFunction) _NuMathClose);
                break;
            }
            case kComponentCanDoSelect:        // Can Do request
            {
                result = CallComponentFunction (params,
                    (ComponentFunction) _NuMathCanDo);
                break;
            }
            case kComponentVersionSelect:    // Version request
            {
                result = CallComponentFunction (params,
                    (ComponentFunction) _NuMathVersion);
                break;
            }
            case kComponentRegisterSelect:    // Register request
            {
                result = CallComponentFunction (params,
                    (ComponentFunction) _NuMathRegister);
                break;
            }
            case kComponentTargetSelect:    // Target request not supported
            default:                        // Unknown request
            {
                result = paramErr;
                break;
            }
        }
    }
    else    // Was it one of our request codes?
    {
        if (globals)
            DelegateComponentCall(params,(**globals).delegateComponentInstance);
        else
            result = paramErr;
    }
    return (result);
}

//-----------------------------------------------------------------------

pascal    ComponentResult    _NuMathOpen    (Handle                storage,
                                     ComponentInstance    self)
{
    ComponentResult        result = noErr;
    PrivateGlobals**    globals;

    // Can we open another instance?
    if (CountComponentInstances ((Component) self) <= kMaxNuMathInstances)
    {
        // Did we get our storage?
        globals = (PrivateGlobals**) NewHandleClear (sizeof (PrivateGlobals));
        if (globals != nil)
        {
            ComponentDescription    delegateDesc;
            Component                delegateComponent = nil;
            ComponentInstance        delegateComponentInstance;
            Component                selfComponent;
            ComponentDescription    tempDesc;

            // Keep a reference to self
            (*globals)->self = (Component) self;

            // Describe the component we want to capture
            delegateDesc.componentType = 'mhlr';
            delegateDesc.componentSubType = 'vide';
            delegateDesc.componentManufacturer = 'appl';
            delegateDesc.componentFlags = 0L;
            delegateDesc.componentFlagsMask = 0L;

            // Keep track of which component we are by querying
            // the component info; the componentFlagsMask will
            // contain the component ID for the component we
            // are requesting info for
            result = GetComponentInfo ((Component) self, &tempDesc, nil, nil, nil);
            selfComponent = (Component)(tempDesc.componentFlagsMask);

            // Find the component we want to capture
            do
            {
                delegateComponent = FindNextComponent (delegateComponent, &delegateDesc);
            }
            while (delegateComponent == selfComponent);

            // Did we find one?
            if (delegateComponent != 0L)
            {
                // Can this component be captured (does it support the
                // target request code)?
                if (ComponentFunctionImplemented ((ComponentInstance) delegateComponent,
                    kComponentTargetSelect))
                {
                    // Capture it
                    delegateComponent = CaptureComponent (delegateComponent,
                        (Component) self);

                    // Keep references to the component we captured
                    (*globals)->delegateComponent = delegateComponent;
                    delegateComponentInstance = OpenComponent (delegateComponent);
                    (*globals)->delegateComponentInstance = delegateComponentInstance;

                    // Did we get an instance of the component we captured?
                    if (delegateComponentInstance != 0L)
                    {
                        // Inform the component it has been captured
                        result = ComponentSetTarget (delegateComponentInstance, self);
                        SetComponentInstanceStorage (self, (Handle) globals);
                    }
                    else    // Couldn't get an instance of the delegate component
                    {
                        DisposHandle ((Handle) globals);
                        result = kGenericError;
                    }
                }
                else    // The component we need can't be captured
                {
                    DisposHandle ((Handle) globals);
                    result = kGenericError;
                }

            }
            else    // Couldn't find the delegate component
            {
                DisposHandle ((Handle) globals);
                result = kGenericError;
            }
        }
        else    // NewHandleClear failed
        {
            result = MemError();
        }
    }
    else    // No more instances can be opened
    {
        result = kGenericError;
    }
    return (result);
}

//-----------------------------------------------------------------------

pascal    ComponentResult    _NuMathClose    (Handle                storage,
                                         ComponentInstance    self)
{
    ComponentResult        result = noErr;
    PrivateGlobals**    globals = (PrivateGlobals**) storage;

    // Do we have any clean up to do?
    if (globals != nil)
    {
        // Any instances to close?
        if ((*globals)->delegateComponentInstance != 0L)
        {
            // Close the captured component instance
            result = CloseComponent ((*globals)->delegateComponentInstance);
            (*globals)->delegateComponentInstance = 0L;

            // Uncapture the captured component (make it visible again)
            result = UncaptureComponent ((*globals)->delegateComponent);
            (*globals)->delegateComponent = 0L;
        }

        // Dispose of globals
        DisposHandle ((Handle) globals);
    }
    return (result);
}

//-----------------------------------------------------------------------

pascal    ComponentResult    _NuMathCanDo    (short    selector)
{
    switch (selector)
    {
        // Component Manager request codes
        case kComponentOpenSelect:
        case kComponentCloseSelect:
        case kComponentCanDoSelect:
        case kComponentVersionSelect:
        case kComponentRegisterSelect:

        // Math component request codes
        case kDoDivideSelect:
        case kDoMultiplySelect:
        {
            return (true);
        }

        // Unsupported request codes
        case kComponentTargetSelect:
        default:
        {
            return (false);
        }
    }
}

//-----------------------------------------------------------------------

pascal    ComponentResult    _NuMathVersion    (void)
{
    // Return the version info
    return (nuMathInterfaceRevision);
}

//-----------------------------------------------------------------------

pascal    ComponentResult    _NuMathRegister    (void)
{
    // See if a Math component is registered - if not, don't
    // register this component, since it can't work without
    // the Math component.  We return zero to register, one
    // to not register.
    ComponentDescription    mathDesc;

    mathDesc.componentType = 'mhlr';
    mathDesc.componentSubType = 'vide';
    mathDesc.componentManufacturer = 'appl';
    mathDesc.componentFlags = 0L;
    mathDesc.componentFlagsMask = 0L;

    return ((FindNextComponent (nil, &mathDesc) != 0L) ? 0L : 1L);
}

//-----------------------------------------------------------------------

pascal    ComponentResult    _NuMathDoDivide    (short    numerator,
                                         short    denominator,
                                         short    *quotient)
{
    ComponentResult    result = noErr;

    // Check for zero denominator
    if (denominator != 0)
    {
        *quotient = (short) Fix2Long
            (FixDiv (Long2Fix ((long) numerator), Long2Fix ((long) denominator)));
    }
    else    // Divide by zero not allowed
    {
        *quotient = 0;
        result = kGenericError;
    }
    return (result);
}

//-----------------------------------------------------------------------

pascal    ComponentResult    _NuMathDoMultiply    (Handle    storage,
                                              short    firstNum,
                                             short    secondNum,
                                             short    *multiplicationResult)
{
    PrivateGlobals**    globals = (PrivateGlobals**) storage;

    // Note that we need access to the component globals because
    // we are delegating the multiply function to the captured
    // Math component, and the component instance of the captured
    // Math component is stored in the NuMath component globals.  In
    // the _MathDoMultiply function in the original Math component,
    // we didn't require access to the component globals, and the
    // interface for this function reflected this (there was no
    // storage parameter).
    return (DoMultiply ((*globals)->delegateComponentInstance, firstNum,
        secondNum, multiplicationResult));
}

//-----------------------------------------------------------------------