ARM平台移植 json-c-0.12

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我是靠谱客的博主兴奋小海豚，最近开发中收集的这篇文章主要介绍ARM平台移植 json-c-0.12，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

系统环境：Ubuntu 14.04.3 LTS
源码：json-c-0.12.tar.gz

交叉编译环境：arm-none-linux-gnueabi-

[zhaojq@virtual-machine ]# tar -xzvf json-c-0.12 .tar.gz

[zhaojq@virtual-machine ]# cd json-c-0.12

[zhaojq@virtual-machine ]# ./configure CC= arm-none-linux-gnueabi-gcc --host=arm-none-linux-gnueabi --build=i686-linux-gnu

手动修改config.h.in，注释掉下面两行

//#undef malloc

//#undef realloc

不然在编译test实例时会出现undefined reference to “rpl_malloc”和undefined reference to “rpl_realloc”两处未定义错误

[zhaojq@virtual-machine ]# libtoolize --version

[zhaojq@virtual-machine]# autoheader --version

查看通用库是否存在，不存在则安装通用库：

[zhaojq@virtual-machine ]# apt-get install libtool

[zhaojq@virtual-machine]# apt-get install autoconf

不然在make时会出现json-c-0.12/missing: line 81: autoheader: command not found等错误

[zhaojq@virtual-machine]# sudo -i

切换到root状态下

不然在make时会出现line 1086: arm-none-linux-gnueabi-ranlib: command not found等错误

[root@virtual-machine]# make

[root@virtual-machine]# make install

安装成功

json头文件在 /usr/local/include/json目录

[zhaojq@virtual-machine /usr/local/include/json-c]# ls

arraylist.h json_config.h json_inttypes.h json_object_private.h linkhash.h
bits.h json_c_version.h json_object.h json_tokener.h printbuf.h
debug.h json.h json_object_iterator.h json_util.h random_seed.h

交叉编译后的动态库文件在 /usr/local/lib目录

[zhaojq@virtual-machine /usr/local/lib]# ls
libjson-c.a libjson-c.so libjson-c.so.2.0.1
libjson-c.la libjson-c.so.2 pkgconfig

编译test实例

[zhaojq@virtual-machine]# vim json_test.cpp

#include <stdio.h>
#include "json.h"

int main(int argc, char *argv[])
{
	struct json_object *infor_object = NULL;
	infor_object = json_object_new_object();
	if (NULL == infor_object)
	{
		printf("new json object failed.n");
		return 0;
	}

	struct json_object *para_object = NULL;
	para_object = json_object_new_object();
	if (NULL == para_object)
	{
		json_object_put(infor_object);
		printf("new json object failed.n");
		return 0;
	}

	struct json_object *array_object = NULL;
	array_object = json_object_new_array();
	if (NULL == array_object)
	{
		json_object_put(infor_object);//free
		json_object_put(para_object);//free
		printf("new json object failed.n");
		return 0;
	}

	/*添加json值类型到数组中*/
	json_object_array_add(array_object, json_object_new_int(256));
	json_object_array_add(array_object, json_object_new_int(257));
	json_object_array_add(array_object, json_object_new_int(258));
	
	/*添加json名称和值到json对象集合中*/
	json_object_object_add(para_object, "DeviceId", json_object_new_string("sn_iso_9000"));
	json_object_object_add(para_object, "MacAddr", json_object_new_string("AA:BB:CC:DD:EE:FF"));
	json_object_object_add(para_object, "Visible", json_object_new_int(1));
	
	json_object_object_add(infor_object, "method", json_object_new_string("GetSystemInfo"));
	json_object_object_add(infor_object, "param", para_object);
	json_object_object_add(infor_object, "id", json_object_new_string("101"));
	
	/*添加数组集合到json对象中*/
	json_object_object_add(infor_object, "array", array_object);

	printf("-----------json infor ---------------------------n");
	printf("%sn", json_object_to_json_string(infor_object));
	printf("-----------json infor ---------------------------n");

	struct json_object *result_object = NULL;
	json_object_object_get_ex(infor_object, "method", &result_object);
	printf("method = %sn", json_object_to_json_string(result_object));

	json_object_object_get_ex(infor_object, "param", &result_object);
	printf("param = %sn", json_object_to_json_string(result_object));

	json_object_object_get_ex(infor_object, "array", &result_object);
	printf("array = %sn", json_object_to_json_string(result_object));
	int i;
	for(i = 0; i < json_object_array_length(result_object); i++)
	{
		struct json_object *obj = json_object_array_get_idx(result_object, i);
		printf("t[%d]=%sn", i, json_object_to_json_string(obj));
	}

	json_object_put(infor_object);//free
	return 0;
}

注：

json-c-0.12版本不能使用json_object_object_get函数，会出现如下warning

warning: 'json_object* json_object_object_get(json_object*, const char*)' is deprecated (declared at /usr/local/include/json-c/json_object.h:290)

所以使用json_object_object_get_ex函数

[zhaojq@virtual-machine]# arm-none-linux-gnueabi-g++ -ljson-c -I/usr/local/include/json-c/ -L/usr/local/lib -o json_test json_test.cpp

编译通过，在当前目录生成json_test可执行文件

将/usr/local/lib目录下得libjson.*和pkgconfig目录都拷贝到ARM设备上文件系统的/lib目录，
将json_test拷贝到ARM设备上

执行./json_test

输出：

-----------json infor ---------------------------
{ "method": "GetSystemInfo", "param": { "DeviceId": "sn_iso_9000", "MacAddr": "AA:BB:CC:DD:EE:FF", "Visible": 1 }, "id": "101", "array": [ 256, 257, 258 ] }
-----------json infor ---------------------------
method = "GetSystemInfo"
param = { "DeviceId": "sn_iso_9000", "MacAddr": "AA:BB:CC:DD:EE:FF", "Visible": 1 }
array = [ 256, 257, 258 ]
[0]=256
[1]=257
[2]=258

移植成功。