Celestin Apprentice 2/Apprentice-Release2.iso/Source Code/C/Frameworks/Extension Shell 1.3/Sample Extensions/WhatKey ƒ/WhatKey.c

C/C++ Source or Header | 1994-04-06 | 6.9 KB | 273 lines | [TEXT/R*ch]

/*    NAME:
        WhatKey.c

    WRITTEN BY:
        Dair Grant

    DESCRIPTION:
        This file contains a CODE resource to be used as a handler by
        Extension Shell.

    ___________________________________________________________________________

    VERSION HISTORY:
        (Jan 1994, dg)
            •    First publicly distributed version.


    ___________________________________________________________________________
*/
//=============================================================================
//        Include files
//-----------------------------------------------------------------------------
#include <GestaltEqu.h>
#include "ParamBlock.h"
#include "StandaloneCode.h"
#include "ESConstants.h"
#include "WhatKey.h"
#include "CodeConstants.h"





//=============================================================================
//        Private function prototypes
//-----------------------------------------------------------------------------
void    main(short theMsg, ESParamBlock *theParamBlock);
void    InitialiseParamBlock(void);
void    InitialiseAddrsTable(void);
void    HandleTheError(void);
void    SetUpIcons(int animDelay, int numIcons, int firstIcon);





//=============================================================================
//        Global variables
//-----------------------------------------------------------------------------
ESParamBlock    *gTheParamBlock;










//=============================================================================
//        main : Entry point to our code resource.
//-----------------------------------------------------------------------------
//        Note :    Extension Shell communicates with us via a message constant,
//                and a pointer to a structure it owns. Our job is to fill in
//                the details, depending on what it wants us to do. It takes
//                care of the rest.
//-----------------------------------------------------------------------------
void main(short theMsg, ESParamBlock *theParamBlock)
{




    // Set up A4 so that we can access our globals, and initialise them.
    GetGlobals();
    gTheParamBlock = theParamBlock;



    // Case out on what we have to do
    switch(theMsg) {
        case kInitialiseParamBlock:
             InitialiseParamBlock();
             break;

        case kInitialiseAddrsTable:
             InitialiseAddrsTable();
             break;

        case kHandleError:
             HandleTheError();
             break;

        default:
             ;
    }



    // Restore A4.
    UngetGlobals();
}










//=============================================================================
//        InitialiseParamBlock : Initialises the ParamBlock.
//-----------------------------------------------------------------------------
//        Note :    We have three things we want to do:
//                    • Check to see if we can still run
//                    • Set up the icons we want to display
//                    • Set up the code we want installed.
//-----------------------------------------------------------------------------
void InitialiseParamBlock(void)
{    int        i;




    // Check for System 7. We depend on having System 7, and won't
    // run if we don't have it. We beep, and post a relevent
    // error message.
    if (gTheParamBlock->systemVersion < 0x0700)
        {
        gTheParamBlock->beepNow                = true;
        gTheParamBlock->postError            = true;
        gTheParamBlock->errorStringsID        = kErrorStrings;
        gTheParamBlock->errorStringIndex    = kNeedSystemSeven;


        // Icon details
        SetUpIcons(kDisabledAnimDelay, kMyNumDisabledIcons, kMyFirstDisabledIcon);
        }



    // If a shift key, or the mouse button, is down, we don't load either.
    // We don't post an error, but just show our disabled icon(s).
    else if ((*gTheParamBlock->UserForcedDisable)(kShiftKey, true))
        {
        // Icon details
        SetUpIcons(kDisabledAnimDelay, kMyNumDisabledIcons, kMyFirstDisabledIcon);
        }



    // Otherwise, we're allowed to run so we show our icon(s) as normal,
    // and install the code we have to install.
    else
        {
        // Icon details
        SetUpIcons(kEnabledAnimDelay, kMyNumEnabledIcons, kMyFirstEnabledIcon);


        // We install one code resource, and use an address table.
        gTheParamBlock->installAddressTable        = true;
        gTheParamBlock->addressTableSelector    = kWhatKeyAddressTable;
        gTheParamBlock->numCodeResources        = 1;


        // Details for our jGNEFilter routine.
        gTheParamBlock->theCodeResources[kWhatKey].resType        = kWhatKeyResType;
        gTheParamBlock->theCodeResources[kWhatKey].resID        = kWhatKeyResID;
        gTheParamBlock->theCodeResources[kWhatKey].codeType        = kLowMemFilterType;
        gTheParamBlock->theCodeResources[kWhatKey].theCodeThing.theLowMemFilter.theEntryPoint = kJGNEFilterAddress;
        }
}










//=============================================================================
//        InitialiseAddrsTable : Initialise the address table.
//-----------------------------------------------------------------------------
//        Note :    If we are being used in a Control Panel, we will probably have
//                implemented the address table code with a custom code resource
//                that returns a structure with an address table embedded at the
//                start. This function's job is to correctly initialise the
//                extended fields of that structure. If we're not using a
//                (custom) address table then we don't do anything.
//
//                The message for this routine will only arrive if we've
//                requested an address table.
//-----------------------------------------------------------------------------
void InitialiseAddrsTable(void)
{



}










//=============================================================================
//        HandleTheError : Handle any errors
//-----------------------------------------------------------------------------
//        Note :    If any error occurs, we beep, post an error, and remove our
//                code. We also have to reset the icon details to show our
//                disabled icons.
//-----------------------------------------------------------------------------
void HandleTheError(void)
{




    // General error handling settings
    gTheParamBlock->removeInstalledCode    = true;
    gTheParamBlock->beepNow                = true;
    gTheParamBlock->postError            = true;
    gTheParamBlock->errorStringsID        = kErrorStrings;



    // Icon details
    SetUpIcons(kDisabledAnimDelay, kMyNumDisabledIcons, kMyFirstDisabledIcon);



    // Just give a general error.
    gTheParamBlock->errorStringIndex = kUnknownError;
}










//=============================================================================
//        SetUpIcons : Set up our icons accordingly.
//-----------------------------------------------------------------------------
//        Note :    We are passed in the resource ID of the first icon, the number
//                of icons, and a delay for animation. We just fill in the fields
//                in the paramBlock.
//-----------------------------------------------------------------------------
void SetUpIcons(int animDelay, int numIcons, int firstIcon)
{    int        i;




    // Fill in the fields
    gTheParamBlock->animationDelay    = animDelay;
    gTheParamBlock->numIcons        = numIcons;
    for (i = 1; i <= numIcons; i++)
        gTheParamBlock->theIcons[i] = firstIcon + i - 1;
}