335 lines
11 KiB
C
335 lines
11 KiB
C
/*
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* $Id$
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*/
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/*
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* Harbour Project source code:
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* Codeblock runtime support
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*
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* Copyright 1999 Ryszard Glab <rglab@imid.med.pl>
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* www - http://www.harbour-project.org
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this software; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
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* Boston, MA 02111-1307 USA (or visit the web site http://www.gnu.org/).
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*
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* As a special exception, the Harbour Project gives permission for
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* additional uses of the text contained in its release of Harbour.
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*
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* The exception is that, if you link the Harbour libraries with other
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* files to produce an executable, this does not by itself cause the
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* resulting executable to be covered by the GNU General Public License.
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* Your use of that executable is in no way restricted on account of
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* linking the Harbour library code into it.
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*
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* This exception does not however invalidate any other reasons why
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* the executable file might be covered by the GNU General Public License.
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*
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* This exception applies only to the code released by the Harbour
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* Project under the name Harbour. If you copy code from other
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* Harbour Project or Free Software Foundation releases into a copy of
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* Harbour, as the General Public License permits, the exception does
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* not apply to the code that you add in this way. To avoid misleading
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* anyone as to the status of such modified files, you must delete
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* this exception notice from them.
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*
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* If you write modifications of your own for Harbour, it is your choice
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* whether to permit this exception to apply to your modifications.
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* If you do not wish that, delete this exception notice.
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*
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*/
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/* The Harbour implementation of codeblocks */
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#include "hbapi.h"
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#include "hbapiitm.h"
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#include "hbvm.h"
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#include "hbstack.h"
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/* Creates the codeblock structure
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*
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* pBuffer -> the buffer with pcodes (without HB_P_PUSHBLOCK)
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* wLocals -> number of local variables referenced in a codeblock
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* pLocalPosTable -> a table with positions on eval stack for referenced variables
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* pSymbols -> a pointer to the module symbol table
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*
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* Note: pLocalPosTable cannot be used if uiLocals is ZERO
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*
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*/
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HB_CODEBLOCK_PTR hb_codeblockNew( BYTE * pBuffer,
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USHORT uiLocals,
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USHORT * pLocalPosTable,
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PHB_SYMB pSymbols )
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{
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HB_CODEBLOCK_PTR pCBlock;
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HB_TRACE(HB_TR_DEBUG, ("hb_codeblockNew(%p, %hu, %p, %p)", pBuffer, uiLocals, pLocalPosTable, pSymbols));
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pCBlock = ( HB_CODEBLOCK_PTR ) hb_gcAlloc( sizeof( HB_CODEBLOCK ), hb_codeblockDeleteGarbage );
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/* Store the number of referenced local variables
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*/
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pCBlock->uiLocals = uiLocals;
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if( uiLocals )
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{
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/* NOTE: if a codeblock will be created by macro compiler then
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* uiLocal have to be ZERO
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* uiLocal will be also ZERO if it is a nested codeblock
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*/
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USHORT ui = 1;
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PHB_ITEM pLocal;
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HB_HANDLE hMemvar;
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/* Create a table that will store the values of local variables
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* accessed in a codeblock
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* The element 0 is used as the counter of references to this table
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* NOTE: This table can be shared by codeblocks created during
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* evaluation of this codeblock
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*/
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pCBlock->pLocals = ( PHB_ITEM ) hb_xgrab( ( uiLocals + 1 ) * sizeof( HB_ITEM ) );
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pCBlock->pLocals[ 0 ].type = HB_IT_LONG;
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pCBlock->pLocals[ 0 ].item.asLong.value = 1;
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while( uiLocals-- )
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{
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/* Swap the current value of local variable with the reference to this
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* value.
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* TODO: If Harbour will support threads in the future then we need
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* to implement some kind of semaphores here.
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*/
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pLocal = hb_stackItemFromBase( *pLocalPosTable++ );
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if( ! HB_IS_MEMVAR( pLocal ) )
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{
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/* Change the value only if this variable is not referenced
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* by another codeblock yet.
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* In this case we have to copy the current value to a global memory
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* pool so it can be shared by codeblocks
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*/
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if( HB_IS_BYREF( pLocal ) )
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{
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pLocal = hb_itemUnRef( pLocal );
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}
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hMemvar = hb_memvarValueNew( pLocal, FALSE );
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pLocal->type = HB_IT_BYREF | HB_IT_MEMVAR;
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pLocal->item.asMemvar.itemsbase = hb_memvarValueBaseAddress();
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pLocal->item.asMemvar.offset = 0;
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pLocal->item.asMemvar.value = hMemvar;
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memcpy( pCBlock->pLocals + ui, pLocal, sizeof( HB_ITEM ) );
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}
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else
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{
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/* This variable is already detached (by another codeblock)
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* - copy the reference to a value
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*/
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/* Increment the reference counter so this value will not be
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* released if other codeblock will be deleted
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*/
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memcpy( pCBlock->pLocals + ui, pLocal, sizeof( HB_ITEM ) );
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}
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hb_memvarValueIncRef( pLocal->item.asMemvar.value );
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++ui;
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}
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}
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else
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{
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/* Check if this codeblock is created during evaluation of another
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* codeblock - all inner codeblocks use the local variables table
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* created during creation of the outermost codeblock
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*/
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PHB_ITEM pLocal;
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pLocal = hb_stackSelfItem();
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if( HB_IS_BLOCK( pLocal ) )
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{
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HB_CODEBLOCK_PTR pOwner = pLocal->item.asBlock.value;
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pCBlock->pLocals = pOwner->pLocals;
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pCBlock->uiLocals = uiLocals = pOwner->uiLocals;
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if( pOwner->pLocals )
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{ /* the outer codeblock have the table with local references - reuse it */
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while( uiLocals )
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{
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hb_memvarValueIncRef( pCBlock->pLocals[ uiLocals ].item.asMemvar.value );
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--uiLocals;
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}
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/* increment a reference counter for the table of local references
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*/
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pCBlock->pLocals[ 0 ].item.asLong.value++;
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}
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}
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else
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pCBlock->pLocals = NULL;
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}
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/*
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* The codeblock pcode is stored in static segment.
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* The only allowed operation on a codeblock is evaluating it then
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* there is no need to duplicate its pcode - just store the pointer to it
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*/
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pCBlock->pCode = pBuffer;
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pCBlock->dynBuffer = FALSE;
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pCBlock->pSymbols = pSymbols;
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pCBlock->ulCounter = 1;
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HB_TRACE(HB_TR_INFO, ("codeblock created (%li) %lx", pCBlock->ulCounter, pCBlock));
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return pCBlock;
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}
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HB_CODEBLOCK_PTR hb_codeblockMacroNew( BYTE * pBuffer, USHORT usLen )
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{
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HB_CODEBLOCK_PTR pCBlock;
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HB_TRACE(HB_TR_DEBUG, ("hb_codeblockMacroNew(%p, %i)", pBuffer, usLen));
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pCBlock = ( HB_CODEBLOCK_PTR ) hb_gcAlloc( sizeof( HB_CODEBLOCK ), hb_codeblockDeleteGarbage );
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/* Store the number of referenced local variables
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*/
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pCBlock->uiLocals = 0;
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pCBlock->pLocals = NULL;
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/*
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* The codeblock pcode is stored in dynamically allocated memory that
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* can be deallocated after creation of a codeblock. We have to duplicate
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* the passed buffer
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*/
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pCBlock->pCode = ( BYTE * ) hb_xgrab( usLen );
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memcpy( pCBlock->pCode, pBuffer, usLen );
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pCBlock->dynBuffer = TRUE;
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pCBlock->pSymbols = NULL; /* macro-compiled codeblock cannot acces a local symbol table */
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pCBlock->ulCounter = 1;
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HB_TRACE(HB_TR_INFO, ("codeblock created (%li) %lx", pCBlock->ulCounter, pCBlock));
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return pCBlock;
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}
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/* Delete a codeblock
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*/
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void hb_codeblockDelete( HB_ITEM_PTR pItem )
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{
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HB_CODEBLOCK_PTR pCBlock = pItem->item.asBlock.value;
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HB_TRACE(HB_TR_DEBUG, ("hb_codeblockDelete(%p)", pItem));
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if( pCBlock && (--pCBlock->ulCounter == 0) )
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{
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if( pCBlock->pLocals )
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{
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USHORT ui = pCBlock->uiLocals;
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while( ui )
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hb_memvarValueDecRef( pCBlock->pLocals[ ui-- ].item.asMemvar.value );
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/* decrement the table reference counter and release memory if
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* it was the last reference
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*/
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if( --pCBlock->pLocals[ 0 ].item.asLong.value == 0 )
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hb_xfree( pCBlock->pLocals );
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}
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/* free space allocated for pcodes - if it was a macro-compiled codeblock
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*/
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if( pCBlock->pCode && pCBlock->dynBuffer )
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{
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hb_xfree( pCBlock->pCode );
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pCBlock->pCode = NULL;
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}
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/* free space allocated for a CODEBLOCK structure
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*/
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hb_gcFree( pCBlock );
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}
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}
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/* Release all allocated memory when called from the garbage collector
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*/
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HB_GARBAGE_FUNC( hb_codeblockDeleteGarbage )
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{
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HB_CODEBLOCK_PTR pCBlock = ( HB_CODEBLOCK_PTR ) Cargo;
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HB_TRACE(HB_TR_DEBUG, ("hb_codeblockDeleteGarbage(%p)", Cargo));
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/* free space allocated for local variables
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*/
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if( pCBlock->pLocals )
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{
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USHORT ui = 1;
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while( ui <= pCBlock->uiLocals )
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{
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hb_memvarValueDecGarbageRef( pCBlock->pLocals[ ui ].item.asMemvar.value );
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++ui;
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}
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/* decrement the table reference counter and release memory if
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* it was the last reference
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*/
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if( --pCBlock->pLocals[ 0 ].item.asLong.value == 0 )
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{
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hb_xfree( pCBlock->pLocals );
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pCBlock->pLocals = NULL;
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}
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}
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/* free space allocated for pcodes - if it was a macro-compiled codeblock
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*/
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if( pCBlock->pCode && pCBlock->dynBuffer )
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{
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hb_xfree( pCBlock->pCode );
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pCBlock->pCode = NULL;
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}
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}
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/* Evaluate passed codeblock
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* Before evaluation we have to switch to a static variable base that
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* was defined when the codeblock was created.
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* (The codeblock can only see the static variables defined in a module
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* where the codeblock was created)
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*/
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void hb_codeblockEvaluate( HB_ITEM_PTR pItem )
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{
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int iStatics = hb_stack.iStatics;
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HB_TRACE(HB_TR_DEBUG, ("hb_codeblockEvaluate(%p)", pItem));
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hb_stack.iStatics = pItem->item.asBlock.statics;
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hb_vmExecute( pItem->item.asBlock.value->pCode, pItem->item.asBlock.value->pSymbols );
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hb_stack.iStatics = iStatics;
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}
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/* Get local variable referenced in a codeblock
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*/
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PHB_ITEM hb_codeblockGetVar( PHB_ITEM pItem, LONG iItemPos )
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{
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HB_CODEBLOCK_PTR pCBlock = pItem->item.asBlock.value;
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HB_TRACE(HB_TR_DEBUG, ("hb_codeblockGetVar(%p, %ld)", pItem, iItemPos));
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/* local variables accessed in a codeblock are always stored as reference */
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return hb_itemUnRef( pCBlock->pLocals - iItemPos );
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}
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/* Get local variable passed by reference
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*/
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PHB_ITEM hb_codeblockGetRef( HB_CODEBLOCK_PTR pCBlock, PHB_ITEM pRefer )
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{
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HB_TRACE(HB_TR_DEBUG, ("hb_codeblockGetRef(%p, %p)", pCBlock, pRefer));
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return pCBlock->pLocals - pRefer->item.asRefer.value;
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}
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