Celestin Apprentice 4/Apprentice-Release4.iso/Source Code/Add-Ons/XCMDs/XCMDTools++/xcmdBase.cp

Text File | 1995-10-05 | 5.4 KB | 207 lines | [TEXT/CWIE]

//    © Paul B. Beeken, Work In Progress, 1994-5
//    Knowledge Software Consulting.
//
//    These files are a mindlessly simple wrapper class for the
//    basic XCMD operations.  Only one instance of the xcmdBase class is
//    generated per XCMD call but there may be many instances of the XCMDString
//    class.  I have used these classes to whip out XCMD/XFCNs within hours of
//    receiving the specs.  They work great for me but I will always consider
//    suggestions.
//
//    Please, please, please, in the unlikely event you should use this stuff
//    for some commercial application I would appreciate you contacting me.  If
//    its for your own use, use away. Send email: [e-mail]
//
//    As always: this file is presented as is with no warrantees expressed or implied.
//    Swim at your own risk, etc. etc.


#include    <ctype.h>
#include    "xcmdBase.h"
#include    <Memory.h>
#include    <String.h>

//
//    This file defines all the methods in the base class.
//    Parameters are passed to client functions as zero terminated strings. All the
//    server calls involving strings expect pascal like string arrays. What to do...
//
//    I have just figured out why the parameters passed to this routine are null
//    term strings: The parameters can be arb. long. The input strings, for example,
//    can be the entire contents of a field container. Pascal strings are limited
//    to 255 bytes. So...
//
//    Any server call made by the client, involving a string will expect a "c" like
//    zero terminated string. The member function converts it to a pascal string, places
//    the call, and converts it back on return. This may seem inefficient but "c" strings
//    are more natural for this language and the alg. for conversion is pretty fast.
//    Besides most of the time we are not tied up in client requests anyway.
//
//    Here's the problem. For some bizare reason the developers of Hypercard
//    pass zero terminated "C" like strings as parameters in the XCmdPtr.
//    This would be OK by    itself until you realize that most of the callback
//    routines want to see pascal like strings. We have created a special class
//    to handle all the string operations.
//

const    int pSiz    = 255;

//XCmdPtr
//xcmdBase::paramPtr    = nil;    // allocated when xcmdBase object is instantiated

//    Creation routine. Registers the XCmdPtr and locks all the parameters high.
//    ____________________________________
xcmdBase::xcmdBase( XCmdPtr xP, Boolean lockParameters ) :
    paramsLocked( lockParameters )
{
    paramPtr = xP;                //    our copy of the paramPtr
    xcmdString::paramPtr = xP;    // common ptr for xcmdString objects.

    //if ( xP )    exitNow = false;  if xp is nil we probably wouldn't be here.

        // I don't automaticlly lock the handles to the parameters.
        // if they are small strings then it may needlessly tie up high memory
        // for other things.
    if ( lockParameters )    lockParams();

}

//    Destruction routine. unlocks all the parameters.
//    ____________________________________
xcmdBase::~xcmdBase( void )
{
    if ( paramsLocked ) unlockParams();
}

//    Unlocks all the parameters.
//    ____________________________________
void
xcmdBase::unlockParams( void )
{
    if ( paramsLocked ) {
        short i;

        for(i=0; i < paramPtr->paramCount; i++) {
            HUnlock(paramPtr->params[i]);
            }
        paramsLocked = false;
        }
}

//    Locks all the parameters.
//    ____________________________________
void
xcmdBase::lockParams( void )
{
    if ( !paramsLocked ) {
        short i;

        for(i=0; i < paramPtr->paramCount; i++) {
            MoveHHi(paramPtr->params[i]);
            HLock(paramPtr->params[i]);
            }
        paramsLocked = true;
        }
}

//    Check the parameter count to see if it is expected.
//    ____________________________________
Boolean
xcmdBase::checkParameters( int min, int max )
{
    if ( paramPtr==nil )    return false;    // no paramPtr so exit

    if (max<min) max=min;

    if ( nParams() < min ) {
        errorMsg( "too few parameters." );
        return false;
        }
    if ( nParams() > max ) {
        errorMsg( "too many parameters." );
        return false;
        }
    return true;
}

//    Array overload. returns the parameter at position i.
//    ____________________________________
Handle
xcmdBase::operator[]( const int i )
{
    if ( i>=0 && i<=16 ) return paramPtr->params[i];
    else return nil;
}

//    Return methods. alerts user of error.
//    ____________________________________
void
xcmdBase::errorMsg( xcmdString msg )
{
    returnMsg( "••Error :" & msg );
}

//    Return methods. returns string.
//    ____________________________________
void
xcmdBase::returnMsg( xcmdString message )
{
    paramPtr->returnValue = Handle(message);
}

/****  HyperTalk Utilities  ****/
Handle
xcmdBase::evalExpr( xcmdString expr )
{
    Handle h = EvalExpr( paramPtr, expr );
    return h;
}

void
xcmdBase::sendCardMessage( xcmdString msg )
{
    // message goes to current card.
    SendCardMessage( paramPtr, msg );

}

void
xcmdBase::sendHCMessage( xcmdString msg )
{
    // message goes to hypercard itself.
    SendHCMessage( paramPtr, msg );
}

void
xcmdBase::runScript( xcmdString handler )
{
    RunHandler( paramPtr, handler );
}

/****  Memory Utilities  ****/
void
xcmdBase::getGlobal( xcmdString globName, xcmdString* rs )
{
    Handle        h = GetGlobal( paramPtr, globName );
    xcmdString    gv( h );
    DisposHandle( h );

    *rs = gv;
}

void
xcmdBase::setGlobal( xcmdString globName, xcmdString& globValue )
{
    Handle gVal = Handle(globValue); // create a handle of the value
    SetGlobal( paramPtr, globName, gVal );
    DisposHandle( gVal );            // dispose of it.
}

void
xcmdBase::zeroBytes( Ptr dstPtr, long longCount )
{
    ZeroBytes( paramPtr, dstPtr, longCount );
}