[XR806开发板试用] XR806 调用cjson 实现数据序列化

很荣幸获得极术设区提供的这次试用机会，可以接触鸿蒙操作系统。我工作接触最多的是linux 平台的嵌入式ARM平台较多，这次跑了下鸿蒙，也非常有趣。

不过接进年底了，日常大小琐碎事情突然多了起来，测评的比较匆忙，目前只把代码拉了下来，跑了几个Demo，遂写点简单的吧，顺带记录下从中遇到的问题，一并贴出来，给后面玩XR806小伙伴一个参考

1. 拉取代码与烧录
   平时开发环境是ubuntu Server 20.04 ，其他的依赖环境也是有的，这里就略过linux 基础环境配置；我测试时候全志分支在往鸿蒙主分支合并，所以主分支中的全志部分没法拉取，我先拉取主分支，在clone 临时仓库的；

不过现在应该恢复了。应该按照官方文档只接获取即可
XR806 WIKI
烧录也是按照官方文档即可
2. 编译配置

A. 在sdk 中 建立如下文件夹和目录

![image.png](/img/bVbo0e)
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B. 修改代码

 **** cjson 文件夹中的main.c 中
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/*
 * Copyright (C) 2021 XRADIO TECHNOLOGY 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 XRADIO TECHNOLOGY CO., LTD. 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
 *  OWNER 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.
 */

#include <stdio.h>
#include "ohos_init.h"
#include "kernel/os/os.h"
#include "cjson/cJSON.h"

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

static OS_Thread_t g_main_thread;






/* Used by some code below as an example datatype. */
struct record
{
    const char *precision;
    double lat;
    double lon;
    const char *address;
    const char *city;
    const char *state;
    const char *zip;
    const char *country;
};


/* Create a bunch of objects as demonstration. */
static int print_preallocated(cJSON *root)
{
    /* declarations */
    char *out = NULL;
    char *buf = NULL;
    char *buf_fail = NULL;
    size_t len = 0;
    size_t len_fail = 0;

    /* formatted print */
    out = cJSON_Print(root);

    /* create buffer to succeed */
    /* the extra 5 bytes are because of inaccuracies when reserving memory */
    len = strlen(out) + 5;
    buf = (char*)malloc(len);
    if (buf == NULL)
    {
        printf("Failed to allocate memory.\n");
        exit(1);
    }

    /* create buffer to fail */
    len_fail = strlen(out);
    buf_fail = (char*)malloc(len_fail);
    if (buf_fail == NULL)
    {
        printf("Failed to allocate memory.\n");
        exit(1);
    }

    /* Print to buffer */
    if (!cJSON_PrintPreallocated(root, buf, (int)len, 1)) {
        printf("cJSON_PrintPreallocated failed!\n");
        if (strcmp(out, buf) != 0) {
            printf("cJSON_PrintPreallocated not the same as cJSON_Print!\n");
            printf("cJSON_Print result:\n%s\n", out);
            printf("cJSON_PrintPreallocated result:\n%s\n", buf);
        }
        free(out);
        free(buf_fail);
        free(buf);
        return -1;
    }

    /* success */
    printf("%s\n", buf);

    /* force it to fail */
    if (cJSON_PrintPreallocated(root, buf_fail, (int)len_fail, 1)) {
        printf("cJSON_PrintPreallocated failed to show error with insufficient memory!\n");
        printf("cJSON_Print result:\n%s\n", out);
        printf("cJSON_PrintPreallocated result:\n%s\n", buf_fail);
        free(out);
        free(buf_fail);
        free(buf);
        return -1;
    }

    free(out);
    free(buf_fail);
    free(buf);
    return 0;
}

/* Create a bunch of objects as demonstration. */
static void create_objects(void)
{
    /* declare a few. */
    cJSON *root = NULL;
    cJSON *fmt = NULL;
    cJSON *img = NULL;
    cJSON *thm = NULL;
    cJSON *fld = NULL;
    int i = 0;

    /* Our "days of the week" array: */
    const char *strings[7] =
    {
        "Sunday",
        "Monday",
        "Tuesday",
        "Wednesday",
        "Thursday",
        "Friday",
        "Saturday"
    };

    volatile double zero = 0.0;


    /* Our "days of the week" array: */
    root = cJSON_CreateStringArray(strings, 7);

    if (print_preallocated(root) != 0) {
        cJSON_Delete(root);
        exit(EXIT_FAILURE);
    }
    cJSON_Delete(root);

}

int  test_main(void)
{
    /* print the version */
    printf("Version: %s\n", cJSON_Version());

    /* Now some samplecode for building objects concisely: */
    create_objects();

    return 0;
}


static void MainThread(void *arg)
{
	LOS_Msleep(10000);
	test_main();
	while (1) {	
	
		LOS_Msleep(1000);
	}
}



void HelloTestMain(void)
{
	printf("Wifi Test Start\n");

	if (OS_ThreadCreate(&g_main_thread, "MainThread", MainThread, NULL,
			    OS_THREAD_PRIO_APP, 4 * 1024) != OS_OK) {
		printf("[ERR] Create MainThread Failed\n");
	}
}

SYS_RUN(HelloTestMain);

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**** cjson文件夹下的BUILD.gn 设置如下：

static_library("app_cjson") {
   configs = []

   sources = [
      "src/main.c",
   ]

   cflags = board_cflags

   include_dirs = board_include_dirs
   include_dirs += [
      "//kernel/liteos_m/kernel/arch/include",
      
   ]
}
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修改xradion/xr806下的BUILD.gn

group("ohosdemo") {
    deps = [
        "cjson:app_cjson",
        #"blink:app_blink",
        #"hello_demo:app_hello",
        #"iot_peripheral:app_peripheral",
        #"wlan_demo:app_WlanTest",
        #"wlan:app_wlan",
        #"httpc:app_httpc",
        
    ]
}
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C. 编译 && 烧写 && 运行

 `hb build -f`
 可能会报固件分区有问题，只接将xxxxx/device/xradio/xr806/xr_skylark/project/demo/audio_demo/image/xr806/image_auto_cal.cfg中的分区拷贝到image.cfg ,重新编译。
 重新烧写，串口调试打印如下：
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D. 附带gitee 代码仓库连接

GitEE