/* l4lock_c.c (c)Copyright Sequiter Software Inc., 1988-1996.  All rights reserved. */

#include "d4all.h"
#ifndef S4UNIX
   #ifdef __TURBOC__
      #pragma hdrstop
   #endif
#endif

#ifdef S4LOCK_CHECK

/* Saves information about all current locks  */
typedef struct
{
   LINK4  link ;
   int     next ;
   int     prev ;
   int     hand ;
   long    startPos ;
   long    len ;
   long    endPos ;
} L4LOCK_INFO ;

static LIST4 lockList ;
static int first =  1 ;
static MEM4 *lockAlloc ;

int S4FUNCTION l4lock_check()
{
   return lockList.nLink ;
}

/* Returns true or false; true means found */
static L4LOCK_INFO *l4lockFind( int h, long p, long l )
{
   L4LOCK_INFO *lPtr ;

   if ( first )
   {
      first =  0 ;
      memset( &lockList, 0, sizeof(lockList) ) ;
      lockAlloc =  mem4create( 0, 20, sizeof(L4LOCK_INFO), 20, 0 ) ;
   }

   for ( lPtr = 0; lPtr = (L4LOCK_INFO *) l4next(&lockList, lPtr); )
   {
      if ( lPtr->hand == h  && lPtr->startPos == p && lPtr->len == l )
         return lPtr ;
      if ( lPtr->hand == h )
      {
         /* Check for Overlap. */
         if ( lPtr->startPos >= p && lPtr->startPos <= p+l-1  ||
              lPtr->endPos >= p   && lPtr->endPos   <= p+l-1  ||
              p >= lPtr->startPos && p <= lPtr->endPos        ||
              p+l-1 >= lPtr->startPos && p+l-1 <= lPtr->endPos )
              {
                 error4( 0, e4result, E86101 ) ;
                 return 0 ; ;
              }
      }
   }
   return 0 ;
}

void S4FUNCTION l4lockRemove( int h, long p, long l )
{
   L4LOCK_INFO *lPtr ;

   lPtr =  l4lockFind( h,p,l ) ;
   if ( lPtr == 0 )
      error4( 0, e4result, E86102 ) ;
   else
      l4remove( &lockList, lPtr ) ;
}

void S4FUNCTION l4lockSave( int h, long p, long l )
{
   L4LOCK_INFO *lPtr ;

   if ( l4lockFind(h,p,l) != 0 )
   {
      error4( 0, e4result, E86101 ) ;
      return ;
   }

   lPtr =  (L4LOCK_INFO *) mem4alloc( lockAlloc ) ;
   if ( lPtr == 0 )
   {
      error4( 0, e4memory, E96102 ) ;
      return ;
   }
   l4add( &lockList, lPtr ) ;

   lPtr->hand = h ;
   lPtr->startPos = p ;
   lPtr->len  = l ;
   lPtr->endPos =  p+l-1 ;
}

#endif