/*
 * $Id$
 */

/*
 * Harbour Project source code:
 * Dynamic symbol table management
 *
 * Copyright 1999 Antonio Linares <alinares@fivetech.com>
 * www - http://www.harbour-project.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.  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 "hbvmopt.h"
#include "hbapi.h"
#include "hbapiitm.h"
#include "hbapierr.h"
#include "hbstack.h"

typedef struct
{
   PHB_DYNS pDynSym;             /* Pointer to dynamic symbol */
} DYNHB_ITEM, * PDYNHB_ITEM, * DYNHB_ITEM_PTR;

typedef struct _HB_SYM_HOLDER
{
   HB_SYMB  symbol;
   struct _HB_SYM_HOLDER * pNext;
   char     szName[ 1 ];
}
HB_SYM_HOLDER, * PHB_SYM_HOLDER;

#if defined( HB_MT_VM )

#  include "hbthread.h"

   static HB_CRITICAL_NEW( s_dynsMtx );
#  define HB_DYNSYM_LOCK      hb_threadEnterCriticalSection( &s_dynsMtx );
#  define HB_DYNSYM_UNLOCK    hb_threadLeaveCriticalSection( &s_dynsMtx );

#  define hb_dynsymHandles( p )     hb_stackGetDynHandle( p )

#else

#  define HB_DYNSYM_LOCK
#  define HB_DYNSYM_UNLOCK

#  define hb_dynsymHandles( p )     ( p )

#endif /* HB_MT_VM */


static PDYNHB_ITEM s_pDynItems = NULL;    /* Pointer to dynamic items */
static USHORT      s_uiDynSymbols = 0;    /* Number of symbols present */

static PHB_SYM_HOLDER s_pAllocSyms = NULL;/* symbols allocated dynamically */

/* Insert new symbol into dynamic symbol table.
 * In MT mode caller should protected it by HB_DYNSYM_LOCK
 */
static PHB_DYNS hb_dynsymInsert( PHB_SYMB pSymbol, UINT uiPos )
{
   PHB_DYNS pDynSym;

   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymInsert(%p,%u)", pSymbol, uiPos));

   if( ++s_uiDynSymbols == 0 )
   {
      --s_uiDynSymbols;
      hb_errInternal( 6004, "Internal error: size of dynamic symbol table exceed", NULL, NULL );
   }
   else if( s_uiDynSymbols == 1 )
   {
      s_pDynItems = ( PDYNHB_ITEM ) hb_xgrab( sizeof( DYNHB_ITEM ) );
   }
   else
   {
      s_pDynItems = ( PDYNHB_ITEM ) hb_xrealloc( s_pDynItems, s_uiDynSymbols * sizeof( DYNHB_ITEM ) );
      memmove( &s_pDynItems[ uiPos + 1 ], &s_pDynItems[ uiPos ],
               sizeof( DYNHB_ITEM ) * ( s_uiDynSymbols - uiPos - 1 ) );
   }

   pDynSym = ( PHB_DYNS ) hb_xgrab( sizeof( HB_DYNS ) );
   memset( pDynSym, 0, sizeof( HB_DYNS ) );
   pDynSym->pSymbol  = pSymbol;
   pDynSym->uiSymNum = s_uiDynSymbols;

   pSymbol->pDynSym = s_pDynItems[ uiPos ].pDynSym = pDynSym;

   return pDynSym;
}

/* Find symbol in dynamic symbol table and set it's position.
 * If not found set position for insert operation.
 * In MT mode caller should protected it by HB_DYNSYM_LOCK
 */
static PHB_DYNS hb_dynsymPos( const char * szName, UINT * puiPos )
{
   UINT uiFirst, uiLast, uiMiddle;

   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymPos(%s,%p)", szName, puiPos));

   uiFirst = 0;
   uiLast = s_uiDynSymbols;
   uiMiddle = uiLast >> 1;

   while( uiFirst < uiLast )
   {
      int iCmp = strcmp( s_pDynItems[ uiMiddle ].pDynSym->pSymbol->szName, szName );

      if( iCmp == 0 )
      {
         *puiPos = uiMiddle;
         return s_pDynItems[ uiMiddle ].pDynSym;
      }
      else if( iCmp < 0 )
         uiLast = uiMiddle;
      else /* if( iCmp > 0 ) */
         uiFirst = uiMiddle + 1;
      uiMiddle = ( uiFirst + uiLast ) >> 1;
   }

   *puiPos = uiMiddle;

   return NULL;
}

/* Create new symbol.
 * In MT mode caller should protected it by HB_DYNSYM_LOCK
 */
static PHB_SYMB hb_symbolAlloc( const char * szName )
{
   PHB_SYM_HOLDER pHolder;
   int iLen;

   HB_TRACE(HB_TR_DEBUG, ("hb_symbolAlloc(%s)", szName));

   iLen = strlen( szName );
   pHolder = ( PHB_SYM_HOLDER ) hb_xgrab( sizeof( HB_SYM_HOLDER ) + iLen );
   memcpy( pHolder->szName, szName, iLen + 1 );
   pHolder->pNext = s_pAllocSyms;
   s_pAllocSyms = pHolder;

   pHolder->symbol.szName        = pHolder->szName;
   pHolder->symbol.scope.value   = 0;
   pHolder->symbol.value.pFunPtr = NULL;
   pHolder->symbol.pDynSym       = NULL;

   return &pHolder->symbol;
}

/* Find symbol in dynamic symbol table */
PHB_DYNS hb_dynsymFind( const char * szName )
{
   UINT uiFirst, uiLast;

   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymFind(%s)", szName));

   HB_DYNSYM_LOCK

   uiFirst = 0;
   uiLast = s_uiDynSymbols;

   while( uiFirst < uiLast )
   {
      UINT uiMiddle = ( uiFirst + uiLast ) >> 1;
      int iCmp = strcmp( s_pDynItems[ uiMiddle ].pDynSym->pSymbol->szName, szName );

      if( iCmp == 0 )
      {
         HB_DYNSYM_UNLOCK
         return s_pDynItems[ uiMiddle ].pDynSym;
      }
      else if( iCmp < 0 )
         uiLast = uiMiddle;
      else /* if( iCmp > 0 ) */
         uiFirst = uiMiddle + 1;
   }

   HB_DYNSYM_UNLOCK

   return NULL;
}

/* Create new symbol */
PHB_SYMB hb_symbolNew( const char * szName )
{
   PHB_SYMB pSymbol;

   HB_TRACE(HB_TR_DEBUG, ("hb_symbolNew(%s)", szName));

   HB_DYNSYM_LOCK

   pSymbol = hb_symbolAlloc( szName );

   HB_DYNSYM_UNLOCK

   return pSymbol;
}

/* creates a new dynamic symbol */
PHB_DYNS hb_dynsymNew( PHB_SYMB pSymbol )
{
   PHB_DYNS pDynSym;
   UINT uiPos;

   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymNew(%p)", pSymbol));

   HB_DYNSYM_LOCK

   pDynSym = hb_dynsymPos( pSymbol->szName, &uiPos ); /* Find position */
   if( ! pDynSym )
      pDynSym = hb_dynsymInsert( pSymbol, uiPos );
   else
   {
      pSymbol->pDynSym = pDynSym;

      if( ( pDynSym->pSymbol->scope.value &
            pSymbol->scope.value & HB_FS_LOCAL ) != 0 &&
            pDynSym->pSymbol != pSymbol )
      {
         /* Someone is using linker which allows to create binaries
          * with multiple function definitions. It's a big chance that
          * wrong binaries are created in such case, f.e both functions
          * linked and not all references updated. Anyhow now we will
          * have to guess which symbol is the real local one [druzus]
          */
         /* Let's check if linker updated function address so both symbols
          * refer to the same function
          */
         if( pDynSym->pSymbol->value.pFunPtr == pSymbol->value.pFunPtr )
         {
            /* The addresses have been updated, f.e. in such way works GCC
             * in Linux (but not MinGW and DJGPP) if user will allow to create
             * binaries with multiple symbols by
             *    -Wl,--allow-multiple-definition
             * when whole module cannot be cleanly replaced.
             * OpenWatcom for Linux, DOS and Windows (I haven't tested OS2
             * version), POCC and XCC (with /FORCE:MULTIPLE) also update
             * addresses in such case.
             *
             * We are guessing that symbols are registered in reverted order
             * so we remove the HB_FS_LOCAL flag from previously registered
             * symbol but some linkers may use different order so it does
             * not have to be true in all cases
             */
            pDynSym->pSymbol->scope.value &= ~HB_FS_LOCAL;
         }
         else
         {
            /* We have multiple symbol with the same name which refer
             * to different public functions inside this single binary
             * Let's check if this symbol is loaded from dynamic library
             * (.so, .dll, .dyn, ...) or .hrb file
             */
            if( pSymbol->scope.value & HB_FS_PCODEFUNC )
            {
               /* It's dynamic module so we are guessing that HVM
                * intentionally not updated function address allowing
                * multiple functions, f.e. programmer asked about keeping
                * local references using HB_LIBLOAD()/HB_HBRLOAD() parameter.
                * In such case update pDynSym address in the new symbol but
                * do not register it as the main one
                */
               HB_DYNSYM_UNLOCK
               return pDynSym;                /* Return pointer to DynSym */
            }
            /* The multiple symbols comes from single binaries - we have to
             * decide what to do with them. We can leave it as is or we can
             * try to overload one symbol so both will point to the same
             * function. For .prg code such overloading will work but not
             * for C code which makes sth like: HB_FUNC_EXEC( funcname )
             * In such case we cannot do anything - we cannot even detect
             * such situation. In some cases even linker cannot detect it
             * because C compiler can make autoinlining or some bindings
             * which are not visible for linker
             */
            /* Let's try to overload one of the functions. Simple:
             *    pDynSym->pSymbol->value.pFunPtr = pSymbol->value.pFunPtr;
             * is not good idea because it's possible that this symbol will
             * be overloaded yet another time after preprocessing rest of
             * symbols so we will use HB_FS_DEFERRED flag which is updated
             * dynamically in hb_vmSend()/hb_vmDo() functions
             */
#define HB_OVERLOAD_MULTIPLE_FUNC

#if defined( HB_OVERLOAD_MULTIPLE_FUNC )
            /* In such way works MinGW, DJGPP, BCC */
#if defined( __GNUC__ ) && !defined( __DJGPP__ )
            /* MinGW (like most of other GCC ports) uses reverted order for
             * initialization functions
             */
            pDynSym->pSymbol->scope.value &= ~HB_FS_LOCAL;
            pDynSym->pSymbol->scope.value |= HB_FS_DEFERRED;
#else
            /* BCC, DJGPP, ... */
            pSymbol->scope.value &= ~HB_FS_LOCAL;
            pSymbol->scope.value |= HB_FS_DEFERRED;
#endif
#endif
         }
      }

      if( ( !pDynSym->pSymbol->value.pFunPtr && pSymbol->value.pFunPtr ) ||
          ( pSymbol->scope.value & HB_FS_LOCAL ) != 0 )
      {
         pDynSym->pSymbol = pSymbol;
#ifndef HB_NO_PROFILER
         pDynSym->ulCalls = 0;
         pDynSym->ulTime  = 0;
         pDynSym->ulRecurse = 0;
#endif
      }
   }

   HB_DYNSYM_UNLOCK

   return pDynSym;
}

/* finds and creates a symbol if not found */
PHB_DYNS hb_dynsymGetCase( const char * szName )
{
   PHB_DYNS pDynSym;
   UINT uiPos;

   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymGetCase(%s)", szName));

   HB_DYNSYM_LOCK

   pDynSym = hb_dynsymPos( szName, &uiPos );
   if( ! pDynSym )
      pDynSym = hb_dynsymInsert( hb_symbolAlloc( szName ), uiPos );

   HB_DYNSYM_UNLOCK

   return pDynSym;
}

PHB_DYNS hb_dynsymGet( const char * szName )  /* finds and creates a symbol if not found */
{
   char szUprName[ HB_SYMBOL_NAME_LEN + 1 ];

   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymGet(%s)", szName));

   /* make a copy as we may get a const string, then turn it to uppercase */
   /* NOTE: This block is optimized for speed [vszakats] */
   {
      int iLen = HB_SYMBOL_NAME_LEN;
      char * pDest = szUprName;

      do
      {
         char cChar = *szName++;
         if( cChar == 0 || cChar == ' ' || cChar == '\t' )
            break;
         else if( cChar >= 'a' && cChar <= 'z' )
            *pDest++ = cChar - ( 'a' - 'A' );
         else
            *pDest++ = cChar;
      }
      while( --iLen );
      *pDest = '\0';
   }

   return hb_dynsymGetCase( szUprName );
}

PHB_DYNS hb_dynsymFindName( const char * szName )  /* finds a symbol */
{
   char szUprName[ HB_SYMBOL_NAME_LEN + 1 ];

   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymFindName(%s)", szName));

   /* make a copy as we may get a const string, then turn it to uppercase */
   /* NOTE: This block is optimized for speed [vszakats] */
   {
      int iLen = HB_SYMBOL_NAME_LEN;
      char * pDest = szUprName;

      do
      {
         char cChar = *szName++;
         if( cChar == 0 || cChar == ' ' || cChar == '\t' )
            break;
         else if( cChar >= 'a' && cChar <= 'z' )
            *pDest++ = cChar - ( 'a' - 'A' );
         else
            *pDest++ = cChar;
      }
      while( --iLen );
      *pDest = '\0';
   }

   return hb_dynsymFind( szUprName );
}

PHB_SYMB hb_dynsymGetSymbol( const char * szName )
{
   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymGetSymbol(%s)", szName));

   return hb_dynsymGet( szName )->pSymbol;
}

PHB_SYMB hb_dynsymFindSymbol( const char * szName )
{
   PHB_DYNS pDynSym;

   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymFindSymbol(%s)", szName));

   pDynSym = hb_dynsymFind( szName );
   return pDynSym ? pDynSym->pSymbol : NULL;
}

PHB_SYMB hb_dynsymSymbol( PHB_DYNS pDynSym )
{
   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymSymbol(%p)", pDynSym));

   return pDynSym->pSymbol;
}

const char * hb_dynsymName( PHB_DYNS pDynSym )
{
   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymName(%p)", pDynSym));

   return pDynSym->pSymbol->szName;
}

BOOL hb_dynsymIsFunction( PHB_DYNS pDynSym )
{
   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymIsFunction(%p)", pDynSym));

   return pDynSym->pSymbol->value.pFunPtr != NULL;
}

PHB_ITEM hb_dynsymGetMemvar( PHB_DYNS pDynSym )
{
   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymGetMemvar(%p)", pDynSym));

   return ( PHB_ITEM ) hb_dynsymHandles( pDynSym )->pMemvar;
}

void hb_dynsymSetMemvar( PHB_DYNS pDynSym, PHB_ITEM pMemvar )
{
   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymSetMemvar(%p,%p)", pDynSym, pMemvar));

   hb_dynsymHandles( pDynSym )->pMemvar = ( void * ) pMemvar;
}

int hb_dynsymAreaHandle( PHB_DYNS pDynSym )
{
   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymAreaHandle(%p)", pDynSym));

   return hb_dynsymHandles( pDynSym )->uiArea;
}

void hb_dynsymSetAreaHandle( PHB_DYNS pDynSym, int iArea )
{
   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymSetAreaHandle(%p,%d)", pDynSym, iArea));

   hb_dynsymHandles( pDynSym )->uiArea = ( USHORT ) iArea;
}

static PHB_DYNS hb_dynsymGetByIndex( long lIndex )
{
   PHB_DYNS pDynSym = NULL;

   HB_DYNSYM_LOCK

   if( lIndex >= 1 && lIndex <= s_uiDynSymbols )
      pDynSym = s_pDynItems[ lIndex - 1 ].pDynSym;

   HB_DYNSYM_UNLOCK

   return pDynSym;
}

long hb_dynsymCount( void )
{
   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymCount()"));

   return s_uiDynSymbols;
}

void hb_dynsymEval( PHB_DYNS_FUNC pFunction, void * Cargo )
{
   PHB_DYNS pDynSym = NULL;
   USHORT uiPos = 0;

   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymEval(%p, %p)", pFunction, Cargo));

   while( TRUE )
   {

      HB_DYNSYM_LOCK

      if( pDynSym )
      {
         /* protection against resizing dynamic symbol by
          * user function or other thread in MT mode
          */
         while( s_pDynItems[ uiPos ].pDynSym != pDynSym )
         {
            if( ++uiPos >= s_uiDynSymbols )
               break;
         }
      }
      if( ++uiPos < s_uiDynSymbols )
         pDynSym = s_pDynItems[ uiPos ].pDynSym;
      else
         pDynSym = NULL;

      HB_DYNSYM_UNLOCK

      if( !pDynSym || !( pFunction )( pDynSym, Cargo ) )
         break;
   }
}

void hb_dynsymProtectEval( PHB_DYNS_FUNC pFunction, void * Cargo )
{
   USHORT uiPos = 0;

   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymProtectEval(%p, %p)", pFunction, Cargo));

   HB_DYNSYM_LOCK

   while( uiPos < s_uiDynSymbols )
   {
      if( !( pFunction )( s_pDynItems[ uiPos++ ].pDynSym, Cargo ) )
         break;
   }

   HB_DYNSYM_UNLOCK
}

void hb_dynsymRelease( void )
{
   HB_TRACE(HB_TR_DEBUG, ("hb_dynsymRelease()"));

   HB_DYNSYM_LOCK

   if( s_uiDynSymbols )
   {
      do
         hb_xfree( ( s_pDynItems + --s_uiDynSymbols )->pDynSym );
      while( s_uiDynSymbols );
      hb_xfree( s_pDynItems );
      s_pDynItems = NULL;
   }

   while( s_pAllocSyms )
   {
      PHB_SYM_HOLDER pHolder = s_pAllocSyms;
      s_pAllocSyms = s_pAllocSyms->pNext;
      hb_xfree( pHolder );
   }

   HB_DYNSYM_UNLOCK
}

HB_FUNC( __DYNSCOUNT ) /* How much symbols do we have: dsCount = __dynsymCount() */
{
   hb_retnint( s_uiDynSymbols );
}

HB_FUNC( __DYNSGETNAME ) /* Get name of symbol: cSymbol = __dynsymGetName( dsIndex ) */
{
   PHB_DYNS pDynSym = hb_dynsymGetByIndex( hb_parnl( 1 ) );

   hb_retc( pDynSym ? pDynSym->pSymbol->szName : NULL );
}

HB_FUNC( __DYNSGETINDEX ) /* Gimme index number of symbol: dsIndex = __dynsymGetIndex( cSymbol ) */
{
   PHB_DYNS pDynSym;
   UINT uiPos = 0;
   char * szName = hb_parc( 1 );

   if( szName )
   {
      pDynSym = hb_dynsymFindName( szName );
      if( pDynSym )
      {
         HB_DYNSYM_LOCK
         if( !hb_dynsymPos( pDynSym->pSymbol->szName, &uiPos ) )
            uiPos = 0;
         HB_DYNSYM_UNLOCK
      }
   }

   hb_retnint( uiPos );
}

HB_FUNC( __DYNSISFUN ) /* returns .t. if a symbol has a function/procedure pointer,
                          given its symbol index */
{
   PHB_DYNS pDynSym = hb_dynsymGetByIndex( hb_parnl( 1 ) );

   hb_retl( pDynSym && hb_dynsymIsFunction( pDynSym ) );
}

HB_FUNC( __DYNSGETPRF ) /* profiler: It returns an array with a function or procedure
                                     called and consumed times { nTimes, nTime }
                                     , given the dynamic symbol index */
{
#ifndef HB_NO_PROFILER
   PHB_DYNS pDynSym = hb_dynsymGetByIndex( hb_parnl( 1 ) );
#endif

   hb_reta( 2 );
   hb_stornl( 0, -1, 1 );
   hb_stornl( 0, -1, 2 );

#ifndef HB_NO_PROFILER
   if( pDynSym )
   {
      if( hb_dynsymIsFunction( pDynSym ) ) /* it is a function or procedure */
      {
         hb_stornl( pDynSym->ulCalls, -1, 1 );
         hb_stornl( pDynSym->ulTime,  -1, 2 );
      }
   }
#endif
}

HB_FUNC( __DYNSN2PTR )
{
   char * szName = hb_parc( 1 );

   hb_retptr( szName ? hb_dynsymGet( szName ) : NULL );
}

HB_FUNC( __DYNSN2SYM )
{
   char * szName = hb_parc( 1 );

   if( szName )
      hb_itemPutSymbol( hb_stackReturnItem(), hb_dynsymGet( szName )->pSymbol );
}

HB_FUNC( __DYNSP2NAME )
{
   PHB_DYNS pDynSym = ( PHB_DYNS ) hb_parptr( 1 );

   hb_retc( pDynSym != NULL ? pDynSym->pSymbol->szName : NULL );
}