common/core/src/ux_utility_string_length_check.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                                                        */
/**                                                                       */
/**   Utility                                                             */
/**                                                                       */
/**************************************************************************/
/**************************************************************************/


/* Include necessary system files.  */

#define UX_SOURCE_CODE

#include "ux_api.h"


/**************************************************************************/
/*                                                                        */
/*  FUNCTION                                               RELEASE        */
/*                                                                        */
/*    _ux_utility_string_length_check                     PORTABLE C      */
/*                                                           6.1.12       */
/*  AUTHOR                                                                */
/*                                                                        */
/*    Chaoqiong Xiao, Microsoft Corporation                               */
/*                                                                        */
/*  DESCRIPTION                                                           */
/*                                                                        */
/*    This function checks if a NULL-terminated C string reaches its end  */
/*    before specified length exceeds.                                    */
/*                                                                        */
/*    On success the actual length of C string is written back to UINT    */
/*    variable pointed by string_length_ptr (if not NULL).                */
/*    Otherwise the variable keeps untouched.                             */
/*                                                                        */
/*    Note NULL terminator is not counted in string length                */
/*    (same as C strlen).                                                 */
/*                                                                        */
/*  INPUT                                                                 */
/*                                                                        */
/*    string                                Pointer to string             */
/*    string_length_ptr                     Pointer to UINT to receive    */
/*                                            the string length           */
/*    max_string_length                     Max string length             */
/*                                                                        */
/*  OUTPUT                                                                */
/*                                                                        */
/*    returns success if the string length was less than the max length,  */
/*    else it returns error                                               */
/*                                                                        */
/*  CALLS                                                                 */
/*                                                                        */
/*    None                                                                */
/*                                                                        */
/*  CALLED BY                                                             */
/*                                                                        */
/*    USBX Components                                                     */
/*                                                                        */
/**************************************************************************/
UINT  _ux_utility_string_length_check(UCHAR *string, UINT *string_length_ptr, UINT max_string_length)
{

UINT    string_length;


    if (string == UX_NULL)
        return(UX_ERROR);

    string_length = 0;

    while (1)
    {

        if (string[string_length] == '\0')
            break;

        string_length++;
        if (string_length > max_string_length)
        {

            /* Error trap. */
            _ux_system_error_handler(UX_SYSTEM_LEVEL_THREAD, UX_SYSTEM_CONTEXT_UTILITY, UX_ERROR);

            return(UX_ERROR);
        }
    }

    if (string_length_ptr)
        *string_length_ptr = string_length;

    return(UX_SUCCESS);
}