CJSON源码研究笔记

参考：http://blog.csdn.net/coding__madman/article/details/51304093
参考：http://blog.csdn.net/lintax/article/details/50993958
参考：https://www.cnblogs.com/chineseboy/p/3959852.html

static void *(*cJSON_malloc)(size_t sz) = malloc;//定义一个函数指针，并初始化指向malloc函数static void (*cJSON_free)(void *ptr) = free;//定义一个函数指，针并初始化指向free函数

typedef struct cJSON{  struct cJSON *next, *prev;   struct cJSON *child;         int type;            //解析的时候用到  char *valuestring;   //值string     int valueint;        //值int         double valuedouble;  //值double      char *string;        //键   键:值   键只有一种，值确有4中：string/int/double/object} cJSON;

实战

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• 第三方库
  
  • cJSON.h
  • cJOSN.c
  • 下载链接：链接：http://pan.baidu.com/s/1miKeVDu 密码：y7b4

//编译时要加上 -lm#include <stdio.h>#include <string.h>#include <stdlib.h>#include "cJSON.h"//拼装int create_js(void){#if 0    cJSON *root;    root = cJSON_CreateObject();    if (!root)    {        printf("get root faild !\n");        return 0;    }    cJSON *js_body;    const char *const body = "body";    cJSON_AddItemToObject(root, body, js_body = cJSON_CreateObject());    cJSON_AddStringToObject(js_body, "name", "xiaohui");    cJSON_AddNumberToObject(js_body, "value", 600);    char *s = cJSON_PrintUnformatted(root);    if (s)    {        printf("%s\n", s);        free(s);        s = NULL;    }    if(root)    {        cJSON_Delete(root);        root = NULL;    }    return 1;#endif#if 0    cJSON *root,*js_body;    root = cJSON_CreateArray();    cJSON_AddItemToArray(root,cJSON_CreateString("hello world"));    cJSON_AddItemToArray(root,cJSON_CreateNumber(10));    char *s = cJSON_Print(root);    char *ss = cJSON_PrintUnformatted(root);    if(s)    {        printf("%s",s);        printf("%s",ss);        free(s);        free(ss);        s = ss = NULL;    }    if(root)    {        cJSON_Delete(root);        root = NULL;    }    return 1;#endif#if 0    cJSON *root,*js_body,*js_list;    root = cJSON_CreateObject();    cJSON_AddItemToObject(root,"body",js_body = cJSON_CreateArray());    cJSON_AddItemToArray(js_body,js_list = cJSON_CreateObject());    cJSON_AddStringToObject(js_list,"name","xiaohong");    cJSON_AddNumberToObject(js_list,"status",100);    char *s = cJSON_PrintUnformatted(root);    if(s)    {        printf("%s\n",s);                free(s);        s = NULL;    }    if(root)    {                cJSON_Delete(root);                root = NULL;            }    return 1;#endif}//解析int parse_js(void){#if 1    //{"list":[{"name":"xiaohong","age":10},{"name":"huahua","age":11}]}    char *js_string = "{\"list\":[{\"name\":\"xiaohong\",\"age\":10},{\"name\":\"huahua\",\"age\":11}]}";    cJSON *root = cJSON_Parse(js_string);    cJSON *js_list = cJSON_GetObjectItem(root, "list");    printf("js_list type is %d\n",js_list->type);    int array_size = cJSON_GetArraySize(js_list);    printf("array size is %d\n", array_size);    int i = 0;    cJSON *item;    cJSON *it;    for (i = 0; i < array_size; ++i)    {        item = cJSON_GetArrayItem(js_list,i);        printf("item type is %d\n",item->type);        it = cJSON_GetObjectItem(item,"name");        printf("it type is %d\n",it->type);        printf("it value is %s\n",it->valuestring);        it = cJSON_GetObjectItem(item,"age");        printf("it type is %d\n",it->type);        printf("it value is %d\n",it->valueint);    }    if(root)    {        cJSON_Delete(root);        root = NULL;    }    return 1;#endif#if 0    //{"list":["name1","name2"]}    char *js_string = "{\"list\":[\"name1\",\"mame2\"]}";    cJSON *root = cJSON_Parse(js_string);    cJSON *js_list = cJSON_GetObjectItem(root,"list");    printf("js_list type is %d\n",js_list->type);    int array_size = cJSON_GetArraySize(js_list);    printf("array size is %d\n",array_size);    int i = 0;    cJSON *item;    for(i = 0;i < array_size;++i)    {        item = cJSON_GetArrayItem(js_list,i);        printf("item type is %d\n",item->type);        printf("%s\n",item->valuestring);    }    if(root)    {        cJSON_Delete(root);        root = NULL;    }    return 0;#endif#if 0    char *js_string = "{\"list\":{\"name\":\"xiaohong\",\"age\":10},\"other\":{\"name\":\"huahua\"}}";    cJSON *root = cJSON_Parse(js_string);    cJSON *js_list = cJSON_GetObjectItem(root,"list");    printf("list type is %d\n",js_list->type);    cJSON *name = cJSON_GetObjectItem(js_list,"name");    printf("name type is %d\n",name->type);    printf("name is %s\n",name->valuestring);    cJSON *age = cJSON_GetObjectItem(js_list,"age");    printf("age type is %d\n",age->type);    printf("age is %d\n",age->valueint);    cJSON *js_other = cJSON_GetObjectItem(root,"other");    printf("other type is %d\n",js_other->type);    cJSON *js_name = cJSON_GetObjectItem(js_list,"name");    printf("js_name type is %d\n",js_name->type);    printf("js_name is %s\n",js_name->valuestring);    if(root)    {        cJSON_Delete(root);        root = NULL;    }    return 0;#endif#if 0    char *js_string = "{\"name\":\"xiao hong\",\"age\":10}";    //{"name":"xiao hong","age":10}        cJSON *root;    root  = cJSON_Parse(js_string);    cJSON *name = cJSON_GetObjectItem(root,"name");        printf("name type is %d\n",name->type);    printf("name is %s\n",name->valuestring);    cJSON *age = cJSON_GetObjectItem(root,"age");    printf("age type is %d\n",age->type);    printf("age is %d\n",age->valueint);    if(root)    {        cJSON_Delete(root);        root = NULL;    }#endif}int main(void){    create_js();//拼装    parse_js(); //解析    return 0;}