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