common/core/src/ux_host_stack_class_instance_get.c


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/***************************************************************************
 * Copyright (c) 2024 Microsoft Corporation
 * Copyright (c) 2026-present Eclipse ThreadX contributors
 *
 * This program and the accompanying materials are made available under the
 * terms of the MIT License which is available at
 * https://opensource.org/licenses/MIT.
 *
 * SPDX-License-Identifier: MIT
 **************************************************************************/


/**************************************************************************/
/**************************************************************************/
/**                                                                       */
/** USBX Component                                                        */
/**                                                                       */
/**   Host Stack                                                          */
/**                                                                       */
/**************************************************************************/
/**************************************************************************/


/* Include necessary system files.  */

#define UX_SOURCE_CODE

#include "ux_api.h"
#include "ux_host_stack.h"


/**************************************************************************/
/*                                                                        */
/*  FUNCTION                                               RELEASE        */
/*                                                                        */
/*    _ux_host_stack_class_instance_get                   PORTABLE C      */
/*                                                           6.1          */
/*  AUTHOR                                                                */
/*                                                                        */
/*    Chaoqiong Xiao, Microsoft Corporation                               */
/*                                                                        */
/*  DESCRIPTION                                                           */
/*                                                                        */
/*    This function returns a class instance pointer for a specific       */
/*    class. The instance of a class is not contained in the class code   */
/*    to reduce the class complexity. Rather, each class instance is      */
/*    attached to class container.                                        */
/*                                                                        */
/*  INPUT                                                                 */
/*                                                                        */
/*    class                                 Pointer to class              */
/*    class_index                           Index of class                */
/*    class_instance                        Destination of class instance */
/*                                            pointer                     */
/*                                                                        */
/*  OUTPUT                                                                */
/*                                                                        */
/*    Completion Status                                                   */
/*                                                                        */
/*  CALLS                                                                 */
/*                                                                        */
/*    None                                                                */
/*                                                                        */
/*  CALLED BY                                                             */
/*                                                                        */
/*    Application                                                         */
/*    USBX Components                                                     */
/*                                                                        */
/**************************************************************************/
UINT  _ux_host_stack_class_instance_get(UX_HOST_CLASS *host_class, UINT class_index, VOID **class_instance)
{

VOID    **current_class_instance;


    /* Start with the first class instance attached to the class container.  */
    current_class_instance =  host_class -> ux_host_class_first_instance;

    /* Check if there are any instances attached.  */
    if(current_class_instance == UX_NULL)
    {

        return(UX_HOST_CLASS_INSTANCE_UNKNOWN);
    }

    /* Traverse the list of the class instances until we found the right one.  */
    while (class_index-- != 0)
    {

        /* Points to the next class instance.  */
        current_class_instance =  *current_class_instance;

        /* Check if we have reached the end of the list of the class instances.  */
        if (current_class_instance == UX_NULL)
        {

            return(UX_HOST_CLASS_INSTANCE_UNKNOWN);
        }
    }

    /* Update the class instance pointer from the caller.  */
    *class_instance =  current_class_instance;

    /* Return successful completion.  */
    return(UX_SUCCESS);
}


/**************************************************************************/
/*                                                                        */
/*  FUNCTION                                               RELEASE        */
/*                                                                        */
/*    _uxe_host_stack_class_instance_get                  PORTABLE C      */
/*                                                           6.3.0        */
/*  AUTHOR                                                                */
/*                                                                        */
/*    Chaoqiong Xiao, Microsoft Corporation                               */
/*                                                                        */
/*  DESCRIPTION                                                           */
/*                                                                        */
/*    This function checks errors in host stack class get function call.  */
/*                                                                        */
/*  INPUT                                                                 */
/*                                                                        */
/*    class                                 Pointer to class              */
/*    class_index                           Index of class                */
/*    class_instance                        Destination of class instance */
/*                                            pointer                     */
/*                                                                        */
/*  OUTPUT                                                                */
/*                                                                        */
/*    None                                                                */
/*                                                                        */
/*  CALLS                                                                 */
/*                                                                        */
/*    _ux_host_stack_class_instance_get     Host stack class instance get */
/*                                                                        */
/*  CALLED BY                                                             */
/*                                                                        */
/*    Application                                                         */
/*                                                                        */
/**************************************************************************/
UINT  _uxe_host_stack_class_instance_get(UX_HOST_CLASS *host_class, UINT class_index, VOID **class_instance)
{

    /* Sanity check.  */
    if ((host_class == UX_NULL) || (class_instance == UX_NULL))
        return(UX_INVALID_PARAMETER);

    /* Invoke class instance get function.  */
    return(_ux_host_stack_class_instance_get(host_class, class_index, class_instance));
}