sbtrdrefcount.cpp

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/* SBtrdRefCount, class for managing reference counts */

 /****************License************************************************
  *
  * Copyright 2000-2003.  ScanSoft, Inc.    
  *
  * Use of this software is subject to notices and obligations set forth 
  * in the SpeechWorks Public License - Software Version 1.2 which is 
  * included with this software. 
  *
  * ScanSoft is a registered trademark of ScanSoft, Inc., and OpenSpeech, 
  * SpeechWorks and the SpeechWorks logo are registered trademarks or 
  * trademarks of SpeechWorks International, Inc. in the United States 
  * and other countries.
  *
  ***********************************************************************/
 

 static const char *rcsid = 0 ? (char *) &rcsid :
 "$Id: SBtrdRefCount.cpp,v 7.1.32.2 2003/10/06 17:57:32 mpanacci Exp $";
 
 // -----1=0-------2=0-------3=0-------4=0-------5=0-------6=0-------7=0-------8
 
 #include <limits.h>                        // For ULONG_MAX
 
 #define SBTRDUTIL_EXPORTS
 #include "SBtrdMutex.hpp"                  // For the GlobalMutex class
 #include "SBtrdRefCount.hpp"               // For this class
 
 // -----1=0-------2=0-------3=0-------4=0-------5=0-------6=0-------7=0-------8
 
 
 // Add a reference to an object
 SBTRDUTIL_API_CLASS VXItrdResult 
 SBtrdRefCount::AddRef (SBtrdRefCount *obj)
 {
   if ( obj == NULL ) return VXItrd_RESULT_INVALID_ARGUMENT;
 
   // Do optional mutex locking
   VXItrdResult rc = VXItrd_RESULT_SUCCESS;
   if (( obj->_mutex ) && 
       ((rc = obj->_mutex->Lock( )) != VXItrd_RESULT_SUCCESS ))
     return rc;
 
   // Increment the reference count
   if ( obj->_refCount < ULONG_MAX )
     (obj->_refCount)++;
   else
     rc = VXItrd_RESULT_FATAL_ERROR;
 
   // Release the mutex lock
   if ( obj->_mutex ) {
     VXItrdResult rc2 =  obj->_mutex->Unlock( );
     if (rc2 != VXItrd_RESULT_SUCCESS )
       rc = rc2;
   }
 
   return rc;
 }
 
 
 // Release a reference. Note: this sets the passed pointer to NULL.
 SBTRDUTIL_API_CLASS VXItrdResult 
 SBtrdRefCount::Release (SBtrdRefCount **obj)
 {
   if (( ! obj ) || ( ! *obj )) return VXItrd_RESULT_INVALID_ARGUMENT;
 
   // Do optional mutex locking
   VXItrdResult rc = VXItrd_RESULT_SUCCESS;
   if (( (*obj)->_mutex ) && 
       ((rc = (*obj)->_mutex->Lock( )) != VXItrd_RESULT_SUCCESS ))
     return rc;
 
   // Decrement the reference count
   unsigned long count = 999;
   if ( (*obj)->_refCount > 0 )
     count = --((*obj)->_refCount);
   else
     rc = VXItrd_RESULT_FATAL_ERROR;
 
   // Release the mutex lock
   if ( (*obj)->_mutex ) {
     VXItrdResult rc2 =  (*obj)->_mutex->Unlock( );
     if (rc2 != VXItrd_RESULT_SUCCESS )
       rc = rc2;
   }
 
   // Invalidate the pointer and return
   if ( count == 0 )
     delete *obj;
   *obj = NULL;
 
   return rc;
 }
 
 
 // Get a unique copy if this is being shared in preparation for a
 // write operation, don't want to change this under someone else's
 // feet. The passed pointer will be changed if this is being shared.
 SBTRDUTIL_API_CLASS VXItrdResult 
 SBtrdRefCount::GetUniqueCopy (SBtrdRefCount **obj,
 			      SBtrdMutex *mutex)
 {
   if (( ! obj ) || ( ! *obj )) return VXItrd_RESULT_INVALID_ARGUMENT;
 
   // Do optional mutex locking
   VXItrdResult rc = VXItrd_RESULT_SUCCESS;
   if (( (*obj)->_mutex ) && 
       ((rc = (*obj)->_mutex->Lock( )) != VXItrd_RESULT_SUCCESS ))
     return rc;
 
   // Do the split if the ref count is greater then 1
   SBtrdRefCount *newObj = NULL;
   if ( (*obj)->_refCount > 1 ) {
     if ( (newObj = (*obj)->AllocateCopy( )) != NULL ) {
       (*obj)->_refCount--;
       if ( mutex )
 	newObj->_mutex = mutex;
     } else {
       rc = VXItrd_RESULT_OUT_OF_MEMORY;
     }
   }
 
   // Release the mutex lock
   if ( (*obj)->_mutex ) {
     VXItrdResult rc2 =  (*obj)->_mutex->Unlock( );
     if (rc2 != VXItrd_RESULT_SUCCESS )
       rc = rc2;
   }
   
   // Return the pointer now that we've unlocked the mutex
   if ( newObj != NULL )
     *obj = newObj;
 
   return rc;
 }