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  1. /****************************************************************************
  2. *
  3. *                            Open Watcom Project
  4. *
  5. *    Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
  6. *
  7. *  ========================================================================
  8. *
  9. *    This file contains Original Code and/or Modifications of Original
  10. *    Code as defined in and that are subject to the Sybase Open Watcom
  11. *    Public License version 1.0 (the 'License'). You may not use this file
  12. *    except in compliance with the License. BY USING THIS FILE YOU AGREE TO
  13. *    ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
  14. *    provided with the Original Code and Modifications, and is also
  15. *    available at www.sybase.com/developer/opensource.
  16. *
  17. *    The Original Code and all software distributed under the License are
  18. *    distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  19. *    EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
  20. *    ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
  21. *    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
  22. *    NON-INFRINGEMENT. Please see the License for the specific language
  23. *    governing rights and limitations under the License.
  24. *
  25. *  ========================================================================
  26. *
  27. * Description:  Implementation of near free() and _nfree().
  28. *
  29. ****************************************************************************/
  30.  
  31.  
  32. //#include "dll.h"        // needs to be first
  33. #include "variety.h"
  34. #include <stddef.h>
  35. #include <malloc.h>
  36. #include "heap.h"
  37. #include "heapacc.h"
  38.  
  39.  
  40. #if defined(__SMALL_DATA__)
  41.  
  42. _WCRTLINK void free( void *stg )
  43. {
  44.     _nfree( stg );
  45. }
  46.  
  47. #endif
  48.  
  49. struct miniheapblkp _WCNEAR     *__MiniHeapFreeRover;
  50.  
  51. _WCRTLINK void _nfree( void _WCNEAR *stg )
  52. {
  53.     mheapptr            p1,p2;
  54.  
  55.     if( !stg )
  56.         return;
  57.  
  58.     _AccessNHeap();
  59.     do {
  60.         // first try some likely locations
  61.         p1 = __MiniHeapFreeRover;
  62.         if( p1 ) {
  63.             if( (PTR)p1 <= (PTR)stg && (PTR)p1+p1->len > (PTR)stg ) {
  64.                 break;
  65.             }
  66.             p2 = p1;
  67.             p1 = p1->prev;
  68.             if( p1 ) {
  69.                 if( (PTR)p1 <= (PTR)stg && (PTR)p1+p1->len > (PTR)stg ) {
  70.                     break;
  71.                 }
  72.             }
  73.             p1 = p2->next;
  74.             if( p1 ) {
  75.                 if( (PTR)p1 <= (PTR)stg && (PTR)p1+p1->len > (PTR)stg ) {
  76.                     break;
  77.                 }
  78.             }
  79.         }
  80.         p1 = __MiniHeapRover;
  81.         if( p1 ) {
  82.             if( (PTR)p1 <= (PTR)stg && (PTR)p1+p1->len > (PTR)stg ) {
  83.                 break;
  84.             }
  85.             p2 = p1;
  86.             p1 = p1->prev;
  87.             if( p1 ) {
  88.                 if( (PTR)p1 <= (PTR)stg && (PTR)p1+p1->len > (PTR)stg ) {
  89.                     break;
  90.                 }
  91.             }
  92.             p1 = p2->next;
  93.             if( p1 ) {
  94.                 if( (PTR)p1 <= (PTR)stg && (PTR)p1+p1->len > (PTR)stg ) {
  95.                     break;
  96.                 }
  97.             }
  98.         }
  99.  
  100.         // not found near rover, so search the list
  101.         for( p1 = __nheapbeg; p1; p1 = p1->next ) {
  102.             if( (PTR)p1 <= (PTR)stg && (PTR)p1+p1->len > (PTR)stg ) {
  103.                 // break twice!
  104.                 goto found_it;
  105.             }
  106.         }
  107.  
  108.         // this pointer is not in the heap
  109.         _ReleaseNHeap();
  110.         return;
  111.     } while( 0 );
  112.  
  113. found_it:
  114.     // we found the miniheap, free the storage
  115.     __MemFree( (unsigned)stg, _DGroup(), (unsigned) p1 );
  116.     __MiniHeapFreeRover = p1;
  117.     if( p1 < __MiniHeapRover ) {
  118.         if( p1->largest_blk > __LargestSizeB4MiniHeapRover ) {
  119.             __LargestSizeB4MiniHeapRover = p1->largest_blk;
  120.         }
  121.     }
  122.     _ReleaseNHeap();
  123. }
  124.