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/*
* @file
*
* @brief Get Object
* @ingroup Score
*/
/*
* COPYRIGHT (c) 1989-1999.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/score/objectimpl.h>
Objects_Control *_Objects_Get(
Objects_Information *information,
Objects_Id id,
Objects_Locations *location
)
{
Objects_Control *the_object;
uint32_t index;
/*
* Extract the index portion of an Id in a way that produces a valid
* index for objects within this class and an invalid value for objects
* outside this class.
*
* If the Id matches the api, class, and node but index portion is 0,
* then the subtraction will underflow and the addition of 1 will
* result in a 0 index. The zeroth element in the local_table is
* always NULL.
*
* If the Id is valid but the object has not been created yet, then
* the local_table entry will be NULL.
*/
index = id - information->minimum_id + 1;
/*
* If the index is less than maximum, then it is OK to use it to
* index into the local_table array.
*/
if ( index <= information->maximum ) {
_Thread_Disable_dispatch();
if ( (the_object = information->local_table[ index ]) != NULL ) {
*location = OBJECTS_LOCAL;
return the_object;
}
/*
* Valid Id for this API, Class and Node but the object has not
* been allocated yet.
*/
_Thread_Enable_dispatch();
*location = OBJECTS_ERROR;
return NULL;
}
/*
* Object Id is not within this API and Class on this node. So
* it may be global in a multiprocessing system. But it is clearly
* invalid on a single processor system.
*/
*location = OBJECTS_ERROR;
#if defined(RTEMS_MULTIPROCESSING)
_Objects_MP_Is_remote( information, id, location, &the_object );
return the_object;
#else
return NULL;
#endif
}
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