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harbour-core/contrib/xhb/cstruct.prg
vszakats 9687850865 2013-03-16 02:10 UTC+0100 Viktor Szakats (harbour syenar.net)
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2013-03-16 02:11:42 +01:00

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/*
* xHarbour Project source code:
* C Structure Support.
*
* Copyright 2000 Ron Pinkas <ronpinkas@profit-master.com>
* www - http://www.xharbour.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this software; see the file COPYING.txt. If not, write to
* the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307 USA (or visit the web site http://www.gnu.org/).
*
* As a special exception, the Harbour Project gives permission for
* additional uses of the text contained in its release of Harbour.
*
* The exception is that, if you link the Harbour libraries with other
* files to produce an executable, this does not by itself cause the
* resulting executable to be covered by the GNU General Public License.
* Your use of that executable is in no way restricted on account of
* linking the Harbour library code into it.
*
* This exception does not however invalidate any other reasons why
* the executable file might be covered by the GNU General Public License.
*
* This exception applies only to the code released by the Harbour
* Project under the name Harbour. If you copy code from other
* Harbour Project or Free Software Foundation releases into a copy of
* Harbour, as the General Public License permits, the exception does
* not apply to the code that you add in this way. To avoid misleading
* anyone as to the status of such modified files, you must delete
* this exception notice from them.
*
* If you write modifications of your own for Harbour, it is your choice
* whether to permit this exception to apply to your modifications.
* If you do not wish that, delete this exception notice.
*
*/
#include "cstruct.ch"
#include "hboo.ch"
#include "error.ch"
#define CLASS_PROPERTIES 6
THREAD STATIC t_aActiveStructure
/* TOFIX: Add mutex protection for variables below. */
STATIC s_aClasses := {}
STATIC s_aArrayClasses := {}
STATIC s_aSynonyms := {}
STATIC s_lInitLongs := .T.
PROCEDURE __init_LONGLONGs()
hb_CStructureCSyntax( "ULONGLONG", { "-4", "ulong[2]", }, , , 8 )
__ClsSetModule( __ActiveStructure() )
hb_CStructureCSyntax( "LONGLONG", { "4", "long[2]", }, , , 8 )
__ClsSetModule( __ActiveStructure() )
RETURN
//
FUNCTION __ActiveStructure( cStructure, nAlign )
#if 0
LOCAL oErr
#endif
LOCAL acMembers, aCTypes, hClass, Counter, cMember
IF s_lInitLongs
s_lInitLongs := .F.
__init_LONGLONGs()
ENDIF
IF PCount() == 2
cStructure := Upper( cStructure )
IF AScan( s_aClasses, {| aClassInfo | aClassInfo[ 1 ] == cStructure } ) > 0
/* In most cases we can simply ignore the redefinition, by returning a FAKED Structure Array! */
#if 0
oErr := ErrorNew()
oErr:Args := { cStructure, nAlign }
oErr:CanDefault := .F.
oErr:CanRetry := .F.
oErr:CanSubstitute := .T.
oErr:Description := "Structure already defined."
oErr:Operation := "__ActiveStructure()"
oErr:Severity := ES_ERROR
oErr:SubCode := 1
oErr:SubSystem := "C Structure"
RETURN Eval( ErrorBlock(), oErr )
#endif
// In most cases we can simply ignore the redefinition, by returning a FAKED Structure Array!
// TraceLog( "Redefinition of C Structure: " + cStructure )
RETURN t_aActiveStructure := { cStructure, NIL, {}, {}, iif( HB_ISNUMERIC( nAlign ), nAlign, 8 ) }
ENDIF
AAdd( s_aClasses, { cStructure, NIL, {}, {}, iif( HB_ISNUMERIC( nAlign ), nAlign, 8 ) } )
// TraceLog( "Registered: " + cStructure, ATail( s_aClasses )[ 5 ] )
t_aActiveStructure := ATail( s_aClasses )
ELSE
// TraceLog( "Created: " + Str( nId ) )
acMembers := t_aActiveStructure[ 3 ]
aCTypes := t_aActiveStructure[ 4 ]
nAlign := t_aActiveStructure[ 5 ]
hClass := __clsNew( "C Structure " + t_aActiveStructure[ 1 ], Len( acMembers ) + CLASS_PROPERTIES )
// __clsDelMsg( hClass, "C" )
t_aActiveStructure[ 2 ] := hClass
__clsAddMsg( hClass, "Reset" , @Reset() , HB_OO_MSG_METHOD )
__clsAddMsg( hClass, "Buffer" , @Buffer() , HB_OO_MSG_METHOD )
__clsAddMsg( hClass, "Value" , @Value() , HB_OO_MSG_METHOD )
__clsAddMsg( hClass, "DeValue" , @DeValue() , HB_OO_MSG_METHOD )
__clsAddMsg( hClass, "Array" , @ArrayMethod() , HB_OO_MSG_METHOD )
__clsAddMsg( hClass, "SayMembers", @SayMembers() , HB_OO_MSG_METHOD )
__clsAddMsg( hClass, "Init" , @Init() , HB_OO_MSG_METHOD )
__clsAddMsg( hClass, "Pointer" , @Pointer() , HB_OO_MSG_METHOD )
__clsAddMsg( hClass, "GetPointer", @GetPointer() , HB_OO_MSG_METHOD )
__clsAddMsg( hClass, "CopyTo" , @__CStr_CopyTo() , HB_OO_MSG_METHOD )
FOR EACH cMember IN acMembers
__clsAddMsg( hClass, cMember, cMember:__enumIndex(), HB_OO_MSG_PROPERTY )
NEXT
Counter := Len( acMembers )
__clsAddMsg( hClass, "aCTypes" , ++Counter, HB_OO_MSG_PROPERTY, acTypes )
__clsAddMsg( hClass, "aCMembers" , ++Counter, HB_OO_MSG_PROPERTY, acMembers, HB_OO_CLSTP_READONLY )
__clsAddMsg( hClass, "nAlign" , ++Counter, HB_OO_MSG_PROPERTY, nAlign, HB_OO_CLSTP_READONLY )
__clsAddMsg( hClass, "SizeOf" , ++Counter, HB_OO_MSG_PROPERTY, hb_SizeOfCstructure( aCTypes, nAlign ), HB_OO_CLSTP_READONLY )
__clsAddMsg( hClass, "_nID" , ++Counter, HB_OO_MSG_PROPERTY, Len( s_aClasses ) )
// WARNING InternalBuffer *MUST* remain the *LAST* Property!!!
__clsAddMsg( hClass, "InternalBuffer", ++Counter, HB_OO_MSG_PROPERTY, , HB_OO_CLSTP_READONLY )
// TraceLog( Len( aCTypes ), aCTypes[ 1 ], aCTypes )
RETURN hClass
ENDIF
RETURN t_aActiveStructure
//
PROCEDURE hb_Member( cMember, CType )
LOCAL nLen, nAt
IF Right( cMember, 1 ) == "]"
nAt := At( "[", cMember )
// nLen := Val( SubStr( cMember, nAt + 1, Len( cMember ) ) )
// Support expressions like x + y, x - y, x * y
nLen := &( SubStr( cMember, nAt + 1, Len( cMember ) - nAt - 1 ) )
AAdd( t_aActiveStructure[ 3 ], Left( cMember, nAt - 1 ) )
AAdd( t_aActiveStructure[ 4 ], hb_CTypeArrayId( CType, nLen ) )
ELSE
AAdd( t_aActiveStructure[ 3 ], cMember )
AAdd( t_aActiveStructure[ 4 ], CType )
ENDIF
RETURN
//
FUNCTION hb_CStructureId( cStructure, lInplace )
LOCAL nID
LOCAL oErr
cStructure := Upper( cStructure )
nID := AScan( s_aClasses, {| aClassInfo | aClassInfo[ 1 ] == cStructure } )
IF nID == 0
nID := AScan( s_aSynonyms, {| aSynonym | aSynonym[ 1 ] == cStructure } )
IF nID == 0
oErr := ErrorNew()
oErr:Args := { cStructure, lInplace }
oErr:CanDefault := .F.
oErr:CanRetry := .F.
oErr:CanSubstitute := .T.
oErr:Description := "Structure not found: '" + cStructure + "'"
oErr:Operation := "hb_CStructureId()"
oErr:Severity := ES_ERROR
oErr:SubCode := 3
oErr:SubSystem := "C Structure"
RETURN Eval( ErrorBlock(), oErr )
ELSE
nID := s_aSynonyms[ nID ][ 2 ]
ENDIF
nID += iif( lInplace, 0, CTYPE_STRUCTURE_PTR - CTYPE_STRUCTURE )
ELSE
nID += iif( lInplace, CTYPE_STRUCTURE, CTYPE_STRUCTURE_PTR )
ENDIF
// TraceLog( cStructure, nID )
RETURN nID
//
PROCEDURE hb_CStructureCSyntax( cStructure, aDefinitions, cTag, cSynonList, nAlign )
LOCAL cElem, nAt, nIndex := 1
LOCAL nLen, Counter, CType
LOCAL oErr
LOCAL nID, cSynon
FOR EACH cElem IN aDefinitions
// *** PP bug - remove when possible! ***
IF cElem == NIL
ASize( aDefinitions, nIndex - 1 )
EXIT
ENDIF
IF ( nAt := At( "*", cElem ) ) > 1
IF nIndex < Len( aDefinitions )
hb_AIns( aDefinitions, nIndex + 1, SubStr( cElem, nAt + 1 ), .T. )
ELSE
AAdd( aDefinitions, SubStr( cElem, nAt + 1 ) )
ENDIF
aDefinitions[ nIndex ] := StrTran( Left( cElem, nAt ), " " )
ELSEIF ( nAt := At( "-", cElem ) ) > 1
IF nIndex < Len( aDefinitions )
hb_AIns( aDefinitions, nIndex + 1, SubStr( cElem, nAt ), .T. )
ELSE
AAdd( aDefinitions, SubStr( cElem, nAt ) )
ENDIF
aDefinitions[ nIndex ] := RTrim( Left( cElem, nAt - 1 ) )
ENDIF
nIndex++
NEXT
__ActiveStructure( cStructure, nAlign )
nID := Len( s_aClasses )
IF ! Empty( cTag )
AAdd( s_aSynonyms, { Upper( cTag ), nID + CTYPE_STRUCTURE } )
// TraceLog( ATail( s_aSynonyms )[ 1 ], ATail( s_aSynonyms )[ 2 ] )
ENDIF
IF ! Empty( cSynonList )
FOR EACH cSynon IN hb_ATokens( cSynonList )
IF Left( cSynon, 1 ) == "*"
AAdd( s_aSynonyms, { Upper( SubStr( cSynon, 2 ) ), nID + CTYPE_STRUCTURE_PTR } )
ELSE
AAdd( s_aSynonyms, { Upper( cSynon ), nID + CTYPE_STRUCTURE } )
ENDIF
// TraceLog( ATail( s_aSynonyms )[ 1 ], ATail( s_aSynonyms )[ 2 ] )
NEXT
ENDIF
nLen := Len( aDefinitions )
FOR Counter := 1 TO nLen STEP 2
// TraceLog( "Member: " + aDefinitions[ Counter + 1 ], "Type: " + aDefinitions[ Counter ] )
CType := aDefinitions[ Counter ]
IF Val( CType ) != 0
hb_Member( aDefinitions[ Counter + 1 ], Val( aDefinitions[ Counter ] ) )
ELSE
IF Right( CType, 1 ) == "*"
CType := hb_CStructureId( Left( CType, Len( CType ) - 1 ), .F. )
ELSE
CType := hb_CStructureId( CType, .T. )
IF CType == CTYPE_STRUCTURE .OR. CType == CTYPE_STRUCTURE_PTR
oErr := ErrorNew()
oErr:Args := { cStructure, aDefinitions, cTag, cSynonList, nAlign }
oErr:CanDefault := .F.
oErr:CanRetry := .F.
oErr:CanSubstitute := .T.
oErr:Description := "Undefined CType: '" + aDefinitions[ Counter ] + "'"
oErr:Operation := "hb_CStructureCSyntax()"
oErr:Severity := ES_ERROR
oErr:SubCode := 2
oErr:SubSystem := "C Structure"
CType := Eval( ErrorBlock(), oErr )
ENDIF
ENDIF
hb_Member( aDefinitions[ Counter + 1 ], CType )
ENDIF
NEXT
RETURN
//
FUNCTION hb_CStructure( cStructure, nAlign )
LOCAL hClass
LOCAL oStructure
LOCAL nID
LOCAL oErr
cStructure := Upper( cStructure )
nID := AScan( s_aClasses, {| aClassInfo | aClassInfo[ 1 ] == cStructure } )
IF nID == 0
oErr := ErrorNew()
oErr:Args := { cStructure, nAlign }
oErr:CanDefault := .F.
oErr:CanRetry := .F.
oErr:CanSubstitute := .T.
oErr:Description := "Structure not initialized with __ActiveStructure()"
oErr:Operation := "hb_CStructure()"
oErr:Severity := ES_ERROR
oErr:SubCode := 3
oErr:SubSystem := "C Structure"
RETURN Eval( ErrorBlock(), oErr )
ENDIF
hClass := s_aClasses[ nId ][ 2 ]
oStructure := __clsInst( hClass )
AllocateMembers( oStructure )
RETURN oStructure
//
STATIC PROCEDURE AllocateMembers( oStructure )
LOCAL aCTypes, CType
aCTypes := oStructure:aCTypes
// TraceLog( "Scaning: " + oStructure:className() )
FOR EACH CType IN aCTypes
IF CType > CTYPE_STRUCTURE .AND. CType < CTYPE_STRUCTURE_PTR
oStructure[ CType:__enumIndex() ] := hb_CStructureFromId( CType, , .F. )
AllocateMembers( oStructure[ CType:__enumIndex() ] )
ENDIF
NEXT
// TraceLog( "Finished: " + oStructure:className() )
RETURN
//
FUNCTION hb_CStructureFromId( nID, nAlign )
LOCAL hClass, oStructure
LOCAL oErr
// TraceLog( nId, s_aClasses )
IF nID > CTYPE_STRUCTURE_PTR
nID -= CTYPE_STRUCTURE_PTR
ELSEIF nID > CTYPE_STRUCTURE
nID -= CTYPE_STRUCTURE
ELSE
oErr := ErrorNew()
oErr:Args := { nID, nAlign }
oErr:CanDefault := .F.
oErr:CanRetry := .F.
oErr:CanSubstitute := .T.
oErr:Description := "ID out of range."
oErr:Operation := "hb_CStructureFromId()"
oErr:Severity := ES_ERROR
oErr:SubCode := 4
oErr:SubSystem := "C Structure"
RETURN Eval( ErrorBlock(), oErr )
ENDIF
IF s_aClasses[ nID ][ 2 ] == NIL
// Meta class was not created yet.
RETURN hb_CStructure( s_aClasses[ nId ][ 1 ] )
ELSE
hClass := s_aClasses[ nId ][ 2 ]
oStructure := __clsInst( hClass )
ENDIF
RETURN oStructure
//
FUNCTION hb_CTypeArrayId( CType, nLen )
LOCAL hClass
LOCAL Counter
LOCAL nID
LOCAL aCTypes, acMembers, cMember
LOCAL cArrayClassName := "C Array of [" + hb_ntos( nLen ) + "] CType: " + Str( CType )
nID := AScan( s_aArrayClasses, {| aArrayDefinitions | aArrayDefinitions[ 1 ] == CType .AND. aArrayDefinitions[ 2 ] == nLen } )
IF nID == 0
hClass := __clsNew( "C Structure " + cArrayClassName, nLen + CLASS_PROPERTIES )
// __clsDelMsg( hClass, "C" )
__ClsSetModule( hClass )
AAdd( s_aClasses, { cArrayClassName, hClass, Array( nLen ), Array( nLen ), 1 } )
nID := Len( s_aClasses )
acMembers := s_aClasses[ nID ][ 3 ]
aCTypes := s_aClasses[ nID ][ 4 ]
// Sames as s_aClasses[ nID ][ 4 ]
AFill( aCTypes, CType )
AAdd( s_aArrayClasses, { CType, nLen, nID } )
__clsAddMsg( hClass, "Reset" , @Reset() , HB_OO_MSG_METHOD )
__clsAddMsg( hClass, "Buffer" , @Buffer() , HB_OO_MSG_METHOD )
__clsAddMsg( hClass, "Value" , @Value() , HB_OO_MSG_METHOD )
__clsAddMsg( hClass, "DeValue" , @DeValue() , HB_OO_MSG_METHOD )
__clsAddMsg( hClass, "Array" , @ArrayMethod() , HB_OO_MSG_METHOD )
__clsAddMsg( hClass, "SayMembers", @SayMembers() , HB_OO_MSG_METHOD )
__clsAddMsg( hClass, "Init" , @Init() , HB_OO_MSG_METHOD )
__clsAddMsg( hClass, "Pointer" , @Pointer() , HB_OO_MSG_METHOD )
__clsAddMsg( hClass, "GetPointer", @GetPointer() , HB_OO_MSG_METHOD )
__clsAddMsg( hClass, "CopyTo" , @__CStr_CopyTo() , HB_OO_MSG_METHOD )
// IF Abs( CType ) == 1
__clsAddMsg( hClass, "AsString", @AsString() , HB_OO_MSG_METHOD )
// ENDIF
FOR Counter := 1 TO nLen
cMember := hb_ntos( Counter )
acMembers[ Counter ] := cMember
__clsAddMsg( hClass, cMember, Counter, HB_OO_MSG_PROPERTY )
NEXT
__clsAddMsg( hClass, "aCTypes" , Counter++, HB_OO_MSG_PROPERTY, aCTypes )
__clsAddMsg( hClass, "aCMembers" , Counter++, HB_OO_MSG_PROPERTY, acMembers, HB_OO_CLSTP_READONLY )
__clsAddMsg( hClass, "nAlign" , Counter++, HB_OO_MSG_PROPERTY, 1, HB_OO_CLSTP_READONLY )
__clsAddMsg( hClass, "SizeOf" , Counter++, HB_OO_MSG_PROPERTY, hb_SizeOfCstructure( aCTypes, 1 ), HB_OO_CLSTP_READONLY )
__clsAddMsg( hClass, "_nID", Counter++, HB_OO_MSG_PROPERTY, nID )
// WARNING InternalBuffer *MUST* remain the *LAST* Property!!!
__clsAddMsg( hClass, "InternalBuffer", Counter, HB_OO_MSG_PROPERTY, , HB_OO_CLSTP_READONLY )
// TraceLog( "Registered: " + cArrayClassName, nID, Len( s_aArrayClasses ), hb_SizeOfCstructure( aCTypes, 1 ), nLen )
ELSE
nID := s_aArrayClasses[ nID ][ 3 ]
// TraceLog( "Reused: " + s_aClasses[ nID ][ 1 ], nID )
ENDIF
RETURN nID + CTYPE_STRUCTURE
//
FUNCTION hb_Is_CStructure( x )
RETURN Left( x:ClassName(), 11 ) == "C Structure"
//
STATIC FUNCTION SayMembers( cPad, lShowMembers, lReturnString )
LOCAL xProperty, cOut := ""
IF cPad == NIL
cPad := ""
ENDIF
IF lShowMembers == NIL
lShowMembers := .F.
ENDIF
IF lReturnString == NIL
lReturnString := .F.
ENDIF
#if 0
QOut( cPad + SubStr( QSelf():className(), 13 ) )
QOut( cPad + Replicate( "-", Len( SubStr( QSelf():className(), 13 ) ) ) )
#endif
cOut += cPad + SubStr( QSelf():className(), 13 )
cOut += hb_eol() + cPad + Replicate( "-", Len( SubStr( QSelf():className(), 13 ) ) )
FOR EACH xProperty IN QSelf():Array
IF hb_Is_CStructure( xProperty )
IF lReturnString
cOut += hb_eol() + hb_eol() + xProperty:SayMembers( cPad + cPad, lShowMembers, lReturnString )
ELSE
xProperty:SayMembers( cPad + cPad, lShowMembers )
ENDIF
ELSE
// QOut( cPad + iif( lShowMembers, acMembers[ xProperty:__enumIndex() ], "" ) + ":", xProperty )
cOut += hb_eol() + cPad + iif( lShowMembers, QSelf():acMembers[ xProperty:__enumIndex() ], "" ) + ":" + hb_CStr( xProperty )
ENDIF
NEXT
IF ! lReturnString
QOut( cOut )
ENDIF
RETURN iif( lReturnString, cOut, QSelf() )
//
STATIC FUNCTION Reset()
LOCAL xProperty, nProperties := Len( QSelf() ) - CLASS_PROPERTIES
FOR EACH xProperty IN QSelf()
IF xProperty:__enumIndex() > nProperties
EXIT
ENDIF
IF hb_Is_CStructure( xProperty )
xProperty:Reset()
ELSE
xProperty := NIL
ENDIF
NEXT
RETURN QSelf()
//
STATIC FUNCTION Buffer( Buffer, lAdopt )
IF HB_ISSTRING( Buffer )
IF Len( Buffer ) < QSelf():SizeOf
// TraceLog( Buffer )
Buffer := PadR( Buffer, QSelf():SizeOf, Chr( 0 ) )
ENDIF
QSelf():InternalBuffer := Buffer
QSelf():DeValue( lAdopt )
ENDIF
IF ! HB_ISSTRING( QSelf():InternalBuffer )
QSelf():InternalBuffer := QSelf():Value()
ENDIF
RETURN QSelf()
//
STATIC FUNCTION GetPointer()
QSelf():InternalBuffer := hb_ArrayToStructure( QSelf(), QSelf():aCTypes, QSelf():nAlign )
RETURN hb_String2Pointer( QSelf():InternalBuffer )
//
STATIC FUNCTION Value()
#if 0
LOCAL aValues := {}
AEval( QSelf(), {| xVal | AAdd( aValues, xVal ) }, 1, Len( QSelf() ) - CLASS_PROPERTIES )
#endif
QSelf():InternalBuffer := hb_ArrayToStructure( QSelf(), QSelf():aCTypes, QSelf():nAlign )
RETURN QSelf():InternalBuffer
//
STATIC FUNCTION DeValue( lAdopt )
#if 0
LOCAL aValues := {}
#endif
LOCAL Buffer := QSelf():InternalBuffer
#if 0
TraceLog( QSelf():ClassName(), QSelf():nAlign, Buffer, Len( Buffer ), lAdopt )
AEval( QSelf(), {| xVal | AAdd( aValues, xVal ) }, 1, Len( QSelf() ) - CLASS_PROPERTIES )
#endif
IF ! HB_ISSTRING( Buffer ) .OR. Len( Buffer ) == 0
// TraceLog( "EMPTY Buffer passed to " + ProcName() )
ELSEIF Len( Buffer ) < QSelf():SizeOf
// TraceLog( "Should have been caught at ::Buffer()!!!", Buffer )
// Buffer := PadR( Buffer, QSelf():SizeOf, Chr( 0 ) )
ELSE
hb_StructureToArray( Buffer, QSelf():aCTypes, QSelf():nAlign, lAdopt, QSelf() )
ENDIF
RETURN QSelf()
//
STATIC FUNCTION ArrayMethod()
LOCAL aValues := {}
AEval( QSelf(), {| xVal | AAdd( aValues, xVal ) }, 1, Len( QSelf() ) - CLASS_PROPERTIES )
RETURN aValues
//
STATIC FUNCTION Init( aValues )
LOCAL xProperty, nLen := Len( aValues )
FOR EACH xProperty IN QSelf()
IF xProperty:__enumIndex() > nLen
EXIT
ENDIF
IF Left( xProperty:className(), 11 ) == "C Structure"
xProperty:Init( aValues[ xProperty:__enumIndex() ] )
ELSE
xProperty := aValues[ xProperty:__enumIndex() ]
ENDIF
NEXT
RETURN QSelf()
//
STATIC FUNCTION Pointer( nNewPointer, lAdopt )
IF nNewPointer != NIL
QSelf():Buffer( hb_Pointer2String( nNewPointer, QSelf():SizeOf ), lAdopt )
ENDIF
RETURN QSelf()
//
STATIC FUNCTION AsString()
LOCAL cChar, nLen := Len( QSelf() ) - CLASS_PROPERTIES, cString := Space( nLen )
FOR EACH cChar IN QSelf()
IF cChar:__enumIndex() > nLen
EXIT
ENDIF
IF cChar == 0
cString := Left( cString, cChar:__enumIndex() - 1 )
EXIT
ENDIF
cString[ cChar:__enumIndex() ] := cChar
NEXT
RETURN cString