bossay_release_out/iot_link/link_misc/link_random.c

/*----------------------------------------------------------------------------
 * Copyright (c) <2018>, <Huawei Technologies Co., Ltd>
 * All rights reserved.
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 * 1. Redistributions of source code must retain the above copyright notice, this list of
 * conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list
 * of conditions and the following disclaimer in the documentation and/or other materials
 * provided with the distribution.
 * 3. Neither the name of the copyright holder nor the names of its contributors may be used
 * to endorse or promote products derived from this software without specific prior written
 * permission.
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *---------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
 * Notice of Export Control Law
 * ===============================================
 * Huawei LiteOS may be subject to applicable export control laws and regulations, which might
 * include those applicable to Huawei LiteOS of U.S. and the country in which you are located.
 * Import, export and usage of Huawei LiteOS in any manner by you shall be in compliance with such
 * applicable export control laws and regulations.
 *---------------------------------------------------------------------------*/
/**
 *  DATE                AUTHOR      INSTRUCTION
 *  2019-05-10 10:26  zhangqianfu  The first version  
 *
 */
#include <stdint.h>
#include <stddef.h>

#include <stdlib.h>
#include <string.h>

#include "cmsis_os2.h"

__attribute__((weak)) int link_random(void* output, int len)
{
    int i;
    int random_number;
    char* pbuf;

    if (NULL == output)
    {
        return -1;
    }

    pbuf = output;
    srand(osKernelGetTickCount() * (1000 / 100));

    for (i = 0; i < len; i += sizeof(int))
    {
        random_number = rand();
        (void) memcpy(pbuf + i, &random_number,
               sizeof(int) > (unsigned int)(len - i)? (unsigned int)(len - i): sizeof(int));
    }

    return 0;
}