一、准备工作
操作系统：centos6.5
cJSON源码：见本文附录

二、 测试文件test.c

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

char * makeJson()
{
    cJSON * pRoot = NULL;
    cJSON * pSub_1 = NULL;
    cJSON * pSub_2 = NULL;

    if((pRoot = cJSON_CreateObject()) == NULL)
    {
        return NULL;
    }
    if((pSub_1 = cJSON_CreateObject()) == NULL)
    {
        return NULL;
    }
    if((pSub_2 = cJSON_CreateObject()) == NULL)
    {
        return NULL;
    }
    cJSON_AddStringToObject(pSub_2, "cStr", "ccccccc");

    cJSON_AddStringToObject(pSub_1, "bStr", "bbbbbbb");
    cJSON_AddItemToObject(pSub_1, "subobject_2", pSub_2);

    cJSON_AddStringToObject(pRoot, "aStr", "aaaaaaa");
    cJSON_AddItemToObject(pRoot, "subobject_1", pSub_1);
    cJSON_AddStringToObject(pRoot, "xStr", "xxxxxxx");

    //cJSON_PrintUnformatted : make json string for Unformatted
    //char * pJson = cJSON_PrintUnformatted(pRoot);

    char * pJson = cJSON_Print(pRoot);
    if(NULL == pJson)
    {
        cJSON_Delete(pRoot);
        return NULL;
    }
    return pJson;
}

int parseJson(const char * pJson)
{
    if(NULL == pJson)
    {
        return 1;
    }
    cJSON * pRoot = cJSON_Parse(pJson);
    if(NULL == pRoot)
    {
        return 2;
    }
    cJSON * pSub_1 = cJSON_GetObjectItem(pRoot, "aStr");
    if(NULL == pSub_1)
    {
        cJSON_Delete(pRoot);
        return 3;
    }
    printf("get aStr : [%s]\n", pSub_1->valuestring);
    pSub_1 = cJSON_GetObjectItem(pRoot, "xStr");
    if(NULL == pSub_1)
    {
        cJSON_Delete(pRoot);
        return 4;
    }
    printf("get xStr : [%s]\n", pSub_1->valuestring);
    pSub_1 = cJSON_GetObjectItem(pRoot, "subobject_1");
    if(NULL == pSub_1)
    {
        cJSON_Delete(pRoot);
        return 5;
    }
    printf("get Sub Obj 1\n");
    cJSON * pSub_2 = cJSON_GetObjectItem(pSub_1, "bStr");
    if(NULL == pSub_2)
    {
        cJSON_Delete(pRoot);
        return 6;
    }
    printf("get bStr : [%s]\n", pSub_2->valuestring);
    pSub_2 = cJSON_GetObjectItem(pSub_1, "subobject_2");
    if(NULL == pSub_2)
    {
        cJSON_Delete(pRoot);
        return 7;
    }
    printf("get Obj 2\n");
    cJSON * pStr = cJSON_GetObjectItem(pSub_2, "cStr");
    if(NULL == pStr)
    {
        cJSON_Delete(pRoot);
        return 8;
    }
    printf("get cStr : [%s]\n", pStr->valuestring);

    cJSON_Delete(pRoot);
    return 0;
}

int main()
{
    char * pJson = makeJson();
    printf("JSON:\n%s\n", pJson);
    parseJson(pJson);
    free(pJson);

    return 0;
}

三、编译执行
新建一个文件夹cJSON，把上面的测试文件test.c保存到文件夹，并把cJSON的源码cJSON.h cJSON.c保存到文件夹
编译代码

#gcc test.c cJSON.c -lm

-lm表示在cJSON.c中用到了math.h这个库，所有要用-lm去连接该库，不然要报错

[root@localhost cjson]# gcc test.c cJSON.c
/tmp/ccRWp0ub.o: In function `parse_number':
cJSON.c:(.text+0x49f): undefined reference to `pow'
/tmp/ccRWp0ub.o: In function `print_number':
cJSON.c:(.text+0x825): undefined reference to `floor'
collect2: ld 返回 1

执行程序，在当前目录下生成a.out可执行程序。

[root@localhost cjson]# ./a.out 
JSON:
{
    "aStr": "aaaaaaa",
    "subobject_1":  {
        "bStr": "bbbbbbb",
        "subobject_2":  {
            "cStr": "ccccccc"
        }
    },
    "xStr": "xxxxxxx"
}
get aStr : [aaaaaaa]
get xStr : [xxxxxxx]
get Sub Obj 1
get bStr : [bbbbbbb]
get Obj 2
get cStr : [ccccccc]
[root@localhost cjson]# 

附录一：cJSON.h源码

/*
  Copyright (c) 2009 Dave Gamble

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  THE SOFTWARE.
*/

#ifndef cJSON__h
#define cJSON__h

#ifdef __cplusplus
extern "C"
{
#endif

/* cJSON Types: 对应cISON结构体的type*/
#define cJSON_False  (1 << 0)
#define cJSON_True   (1 << 1)
#define cJSON_NULL   (1 << 2)
#define cJSON_Number (1 << 3)
#define cJSON_String (1 << 4)
#define cJSON_Array  (1 << 5)
#define cJSON_Object (1 << 6)

#define cJSON_IsReference 256
#define cJSON_StringIsConst 512

/* The cJSON structure: */
typedef struct cJSON
{
    /* next/prev allow you to walk array/object chains. Alternatively, use GetArraySize/GetArrayItem/GetObjectItem */
    struct cJSON *next;//双向链表指针
    struct cJSON *prev;//双向链表指针
    /* An array or object item will have a child pointer pointing to a chain of the items in the array/object. */
    struct cJSON *child;//第一个儿子的指针

    /* The type of the item, as above. */
    int type;

    /* The item's string, if type==cJSON_String */
    char *valuestring;
    /* The item's number, if type==cJSON_Number */
    int valueint;
    /* The item's number, if type==cJSON_Number */
    double valuedouble;

    /* The item's name string, if this item is the child of, or is in the list of subitems of an object. */
    char *string; //如果是对象的key_value元素的话， key值
} cJSON;

typedef struct cJSON_Hooks
{
      void *(*malloc_fn)(size_t sz);
      void (*free_fn)(void *ptr);
} cJSON_Hooks;

/* Supply malloc, realloc and free functions to cJSON */
extern void cJSON_InitHooks(cJSON_Hooks* hooks);


/* Supply a block of JSON, and this returns a cJSON object you can interrogate. Call cJSON_Delete when finished. */
extern cJSON *cJSON_Parse(const char *value);
/* Render a cJSON entity to text for transfer/storage. Free the char* when finished. */
extern char  *cJSON_Print(const cJSON *item);
/* Render a cJSON entity to text for transfer/storage without any formatting. Free the char* when finished. */
extern char  *cJSON_PrintUnformatted(const cJSON *item);
/* Render a cJSON entity to text using a buffered strategy. prebuffer is a guess at the final size. guessing well reduces reallocation. fmt=0 gives unformatted, =1 gives formatted */
extern char *cJSON_PrintBuffered(const cJSON *item, int prebuffer, int fmt);
/* Delete a cJSON entity and all subentities. */
extern void   cJSON_Delete(cJSON *c);

/* Returns the number of items in an array (or object). */
extern int    cJSON_GetArraySize(const cJSON *array);
/* Retrieve item number "item" from array "array". Returns NULL if unsuccessful. */
extern cJSON *cJSON_GetArrayItem(const cJSON *array, int item);
/* Get item "string" from object. Case insensitive. */
extern cJSON *cJSON_GetObjectItem(const cJSON *object, const char *string);
extern int cJSON_HasObjectItem(const cJSON *object, const char *string);
/* For analysing failed parses. This returns a pointer to the parse error. You'll probably need to look a few chars back to make sense of it. Defined when cJSON_Parse() returns 0. 0 when cJSON_Parse() succeeds. */
extern const char *cJSON_GetErrorPtr(void);

/* These calls create a cJSON item of the appropriate type. */
extern cJSON *cJSON_CreateNull(void);
extern cJSON *cJSON_CreateTrue(void);
extern cJSON *cJSON_CreateFalse(void);
extern cJSON *cJSON_CreateBool(int b);
extern cJSON *cJSON_CreateNumber(double num);
extern cJSON *cJSON_CreateString(const char *string);
extern cJSON *cJSON_CreateArray(void);
extern cJSON *cJSON_CreateObject(void);

/* These utilities create an Array of count items. */
extern cJSON *cJSON_CreateIntArray(const int *numbers, int count);
extern cJSON *cJSON_CreateFloatArray(const float *numbers, int count);
extern cJSON *cJSON_CreateDoubleArray(const double *numbers, int count);
extern cJSON *cJSON_CreateStringArray(const char **strings, int count);

/* Append item to the specified array/object. */
extern void cJSON_AddItemToArray(cJSON *array, cJSON *item);
extern void cJSON_AddItemToObject(cJSON *object, const char *string, cJSON *item);
extern void cJSON_AddItemToObjectCS(cJSON *object, const char *string, cJSON *item);    /* Use this when string is definitely const (i.e. a literal, or as good as), and will definitely survive the cJSON object */
/* Append reference to item to the specified array/object. Use this when you want to add an existing cJSON to a new cJSON, but don't want to corrupt your existing cJSON. */
extern void cJSON_AddItemReferenceToArray(cJSON *array, cJSON *item);
extern void cJSON_AddItemReferenceToObject(cJSON *object, const char *string, cJSON *item);

/* Remove/Detatch items from Arrays/Objects. */
extern cJSON *cJSON_DetachItemFromArray(cJSON *array, int which);
extern void   cJSON_DeleteItemFromArray(cJSON *array, int which);
extern cJSON *cJSON_DetachItemFromObject(cJSON *object, const char *string);
extern void   cJSON_DeleteItemFromObject(cJSON *object, const char *string);

/* Update array items. */
extern void cJSON_InsertItemInArray(cJSON *array, int which, cJSON *newitem); /* Shifts pre-existing items to the right. */
extern void cJSON_ReplaceItemInArray(cJSON *array, int which, cJSON *newitem);
extern void cJSON_ReplaceItemInObject(cJSON *object,const char *string,cJSON *newitem);

/* Duplicate a cJSON item */
extern cJSON *cJSON_Duplicate(const cJSON *item, int recurse);
/* Duplicate will create a new, identical cJSON item to the one you pass, in new memory that will
need to be released. With recurse!=0, it will duplicate any children connected to the item.
The item->next and ->prev pointers are always zero on return from Duplicate. */

/* ParseWithOpts allows you to require (and check) that the JSON is null terminated, and to retrieve the pointer to the final byte parsed. */
/* If you supply a ptr in return_parse_end and parsing fails, then return_parse_end will contain a pointer to the error. If not, then cJSON_GetErrorPtr() does the job. */
extern cJSON *cJSON_ParseWithOpts(const char *value, const char **return_parse_end, int require_null_terminated);

extern void cJSON_Minify(char *json);

/* Macros for creating things quickly. */
#define cJSON_AddNullToObject(object,name) cJSON_AddItemToObject(object, name, cJSON_CreateNull())
#define cJSON_AddTrueToObject(object,name) cJSON_AddItemToObject(object, name, cJSON_CreateTrue())
#define cJSON_AddFalseToObject(object,name) cJSON_AddItemToObject(object, name, cJSON_CreateFalse())
#define cJSON_AddBoolToObject(object,name,b) cJSON_AddItemToObject(object, name, cJSON_CreateBool(b))
#define cJSON_AddNumberToObject(object,name,n) cJSON_AddItemToObject(object, name, cJSON_CreateNumber(n))
#define cJSON_AddStringToObject(object,name,s) cJSON_AddItemToObject(object, name, cJSON_CreateString(s))

/* When assigning an integer value, it needs to be propagated to valuedouble too. */
#define cJSON_SetIntValue(object,val) ((object) ? (object)->valueint = (object)->valuedouble = (val) : (val))
#define cJSON_SetNumberValue(object,val) ((object) ? (object)->valueint = (object)->valuedouble = (val) : (val))

/* Macro for iterating over an array */
#define cJSON_ArrayForEach(pos, head) for(pos = (head)->child; pos != NULL; pos = pos->next)
#ifdef __cplusplus
}
#endif
#endif

附录二：cJSON.c源码

/*
  Copyright (c) 2009 Dave Gamble

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  THE SOFTWARE.
*/

/* cJSON */
/* JSON parser in C. */

#include <string.h>
#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <float.h>
#include <limits.h>
#include <ctype.h>
#include "cJSON.h"
/*定义一个全局静态字符指针变量，该指针指向一个常量（即指向的数据为常量），这个常量在本文件中只出现了3个地方*/
static const char *global_ep;

/*if (!json) {printf("Error before: [%s]\n",cJSON_GetErrorPtr());}
这个短短一行代码的函数其实就是当传入的字符串解析失败就返回解析失败处的地址后边的字符串！*/
const char *cJSON_GetErrorPtr(void)
{
    return global_ep;
}
/*用来比较参数s1和s2字符串，比较时会自动忽略大小写的差异。返回值 若参数s1和s2字符串相同则返回0。
s1长度大于s2长度则返回大于0 的值，s1 长度若小于s2 长度则返回小于0的值.(对照着下面源码分析应该已经很清晰了)*/
/* case insensitive strcmp */
static int cJSON_strcasecmp(const char *s1, const char *s2)
{
    if (!s1)//等价于if(null == s1)
    {
        return (s1 == s2) ? 0 : 1; /* both NULL? */
    }
    if (!s2)
    {
        return 1;
    }
    for(; tolower(*s1) == tolower(*s2); ++s1, ++s2)
    {
        if (*s1 == 0)
        {
            return 0;
        }
    }

    return tolower(*(const unsigned char *)s1) - tolower(*(const unsigned char *)s2);
    /*tolower若参数 c 为大写字母则将该对应的小写字母返回。返回转换后的小写字母，若不须转换则将参数c 值返回*/
}

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;//同上，这里有一个很巧妙灵活的功能，下边会提到

/*将传入的字符串复制一副本并返回新的字符串指针*/
static char* cJSON_strdup(const char* str)
{
    size_t len;
    char* copy;

    len = strlen(str) + 1;
    if (!(copy = (char*)cJSON_malloc(len)))
    {
        return 0;
    }
    memcpy(copy, str, len);

    return copy;
}

/*Hook内存管理函数,默认申请、释放内存函数malloc、free 也可以自定内存管理函数，增加灵活度。*/
void cJSON_InitHooks(cJSON_Hooks* hooks)
{
    if (!hooks)
    {
        /* Reset hooks */ //如果hooks为空，使用默认的内存管理
        cJSON_malloc = malloc;
        cJSON_free = free;
        return;
    }

    cJSON_malloc = (hooks->malloc_fn) ? hooks->malloc_fn : malloc;
    cJSON_free = (hooks->free_fn) ? hooks->free_fn : free;
}

/*内存管理函数，new一个cJSON节点（对象）出来，并返回指向该节点的地址， 注意返回类型为（cJSON *）型*/
/* Internal constructor. */
static cJSON *cJSON_New_Item(void)
{
    cJSON* node = (cJSON*)cJSON_malloc(sizeof(cJSON));//malloc出一个节点
    if (node)
    {
        memset(node, 0, sizeof(cJSON));//将内存初始化为0
    }

    return node;
}
/*删除一个cJSON节点，先删除儿子节点，然后删除自己。对于字符串，需要先释放字符串的内存然后再释放自己的这块内存，对于其他节点，直接释放自己这块内存*/

/* Delete a cJSON structure. */
void cJSON_Delete(cJSON *c)
{
    cJSON *next;
    while (c)
    {
        next = c->next;
        if (!(c->type & cJSON_IsReference) && c->child)
        {
            cJSON_Delete(c->child);//先递归删除自己的儿子节点
        }
        if (!(c->type & cJSON_IsReference) && c->valuestring)
        {
            cJSON_free(c->valuestring);
        }
        if (!(c->type & cJSON_StringIsConst) && c->string)
        {
            cJSON_free(c->string);
        }
        cJSON_free(c);
        c = next;
    }
}

/*解析输入文本生成一个数字,并填充结果项
传入的参数有两个，这里先只关注num， 返回值是一个字符串*/
/* Parse the input text to generate a number, and populate the result into item. */
static const char *parse_number(cJSON *item, const char *num)
{
    double n = 0;
    double sign = 1;
    double scale = 0;
    int subscale = 0;
    int signsubscale = 1;

    /* Has sign? */
    if (*num == '-')/* 判断是否为正负数 */
    {
        sign = -1;
        num++;
    }
    /* is zero */
    if (*num == '0')
    {
        num++;
    }
    /* Number? */
    if ((*num >= '1') && (*num <= '9'))
    {
        do
        {
            n = (n * 10.0) + (*num++ - '0');
        }
        while ((*num >= '0') && (*num<='9'));
    }
    /* Fractional part? */
    if ((*num == '.') && (num[1] >= '0') && (num[1] <= '9'))
    {
        num++;
        do
        {
            n = (n  *10.0) + (*num++ - '0');
            scale--;
        } while ((*num >= '0') && (*num <= '9'));
    }
    /* Exponent? */
    if ((*num == 'e') || (*num == 'E'))
    {
        num++;
        /* With sign? */
        if (*num == '+')
        {
            num++;
        }
        else if (*num == '-')
        {
            signsubscale = -1;
            num++;
        }
        /* Number? */
        while ((*num>='0') && (*num<='9'))
        {
            subscale = (subscale * 10) + (*num++ - '0');
        }
    }

    /* number = +/- number.fraction * 10^+/- exponent */
    n = sign * n * pow(10.0, (scale + subscale * signsubscale));

    item->valuedouble = n;
    item->valueint = (int)n;
    item->type = cJSON_Number;

    return num;
}

/*将一个数后边所有的位都置1然后再+1*/
/* calculate the next largest power of 2 */
static int pow2gt (int x)
{
    --x;

    x |= x >> 1;
    x |= x >> 2;
    x |= x >> 4;
    x |= x >> 8;
    x |= x >> 16;

    return x + 1;
}

/* ensure 函数 是一个 协助 printbuffer 分配内存的一个函数  
 * len 表示当前字符串的字符串起始偏移量 即 newbuffer+p->offset 起始的
 */
typedef struct
{
    char *buffer;
    int length;
    int offset;
} printbuffer;

/*协助分配内存*/
/* realloc printbuffer if necessary to have at least "needed" bytes more */
static char* ensure(printbuffer *p, int needed)
{
    char *newbuffer;
    int newsize;
    if (!p || !p->buffer)
    {
        return 0;
    }
    needed += p->offset;
    if (needed <= p->length)
    {
        return p->buffer + p->offset;
    }

    newsize = pow2gt(needed);
    newbuffer = (char*)cJSON_malloc(newsize);
    if (!newbuffer)
    {
        cJSON_free(p->buffer);
        p->length = 0;
        p->buffer = 0;

        return 0;
    }
    if (newbuffer)
    {
        memcpy(newbuffer, p->buffer, p->length);
    }
    cJSON_free(p->buffer);
    p->length = newsize;
    p->buffer = newbuffer;

    return newbuffer + p->offset;
}

/*返回的是一个地址，偏移量加上字符串str长度的地址，但这里char *str只是个局部指针变量！该指针指向原有的buffer+offset地址处后面的字符串，返回值是一个int型*/
/* calculate the new length of the string in a printbuffer */
static int update(const printbuffer *p)
{
    char *str;
    if (!p || !p->buffer)
    {
        return 0;
    }
    str = p->buffer + p->offset;

    return p->offset + strlen(str);
}

/*返回值为一个字符串地址,这里看到sprintf的这种用法就知道是讲数字转换为字符串数组！*/
/* Render the number nicely from the given item into a string. */
static char *print_number(const cJSON *item, printbuffer *p)
{
    char *str = 0;
    double d = item->valuedouble;
    /* special case for 0. */
    if (d == 0)
    {
        if (p)
        {
            str = ensure(p, 2);
        }
        else
        {
            str = (char*)cJSON_malloc(2);
        }
        if (str)
        {
            strcpy(str,"0");
        }
    }
    /* value is an int */
    else if ((fabs(((double)item->valueint) - d) <= DBL_EPSILON) && (d <= INT_MAX) && (d >= INT_MIN))
    {
        if (p)
        {
            str = ensure(p, 21);
        }
        else
        {
            /* 2^64+1 can be represented in 21 chars. */
            str = (char*)cJSON_malloc(21);
        }
        if (str)
        {
            sprintf(str, "%d", item->valueint);
        }
    }
    /* value is a floating point number */
    else
    {
        if (p)
        {
            /* This is a nice tradeoff. */
            str = ensure(p, 64);
        }
        else
        {
            /* This is a nice tradeoff. */
            str=(char*)cJSON_malloc(64);
        }
        if (str)
        {
            /* This checks for NaN and Infinity */
            if ((d * 0) != 0)
            {
                sprintf(str, "null");
            }
            else if ((fabs(floor(d) - d) <= DBL_EPSILON) && (fabs(d) < 1.0e60))
            {
                sprintf(str, "%.0f", d);
            }
            else if ((fabs(d) < 1.0e-6) || (fabs(d) > 1.0e9))
            {
                sprintf(str, "%e", d);
            }
            else
            {
                sprintf(str, "%f", d);
            }
        }
    }
    return str;
}

/*将十六进制的字符串转换为数字表示*/
/* parse 4 digit hexadecimal number */
static unsigned parse_hex4(const char *str)
{
    unsigned h = 0;
    /* first digit */
    if ((*str >= '0') && (*str <= '9'))
    {
        h += (*str) - '0';
    }
    else if ((*str >= 'A') && (*str <= 'F'))
    {
        h += 10 + (*str) - 'A';
    }
    else if ((*str >= 'a') && (*str <= 'f'))
    {
        h += 10 + (*str) - 'a';
    }
    else /* invalid */
    {
        return 0;
    }


    /* second digit */
    h = h << 4;
    str++;
    if ((*str >= '0') && (*str <= '9'))
    {
        h += (*str) - '0';
    }
    else if ((*str >= 'A') && (*str <= 'F'))
    {
        h += 10 + (*str) - 'A';
    }
    else if ((*str >= 'a') && (*str <= 'f'))
    {
        h += 10 + (*str) - 'a';
    }
    else /* invalid */
    {
        return 0;
    }

    /* third digit */
    h = h << 4;
    str++;
    if ((*str >= '0') && (*str <= '9'))
    {
        h += (*str) - '0';
    }
    else if ((*str >= 'A') && (*str <= 'F'))
    {
        h += 10 + (*str) - 'A';
    }
    else if ((*str >= 'a') && (*str <= 'f'))
    {
        h += 10 + (*str) - 'a';
    }
    else /* invalid */
    {
        return 0;
    }

    /* fourth digit */
    h = h << 4;
    str++;
    if ((*str >= '0') && (*str <= '9'))
    {
        h += (*str) - '0';
    }
    else if ((*str >= 'A') && (*str <= 'F'))
    {
        h += 10 + (*str) - 'A';
    }
    else if ((*str >= 'a') && (*str <= 'f'))
    {
        h += 10 + (*str) - 'a';
    }
    else /* invalid */
    {
        return 0;
    }

    return h;
}

/* first bytes of UTF8 encoding for a given length in bytes */
static const unsigned char firstByteMark[7] =
{
    0x00, /* should never happen */
    0x00, /* 0xxxxxxx */
    0xC0, /* 110xxxxx */
    0xE0, /* 1110xxxx */
    0xF0, /* 11110xxx */
    0xF8,
    0xFC
};

/* Parse the input text into an unescaped cstring, and populate item. */
static const char *parse_string(cJSON *item, const char *str, const char **ep)
{
    const char *ptr = str + 1;
    const char *end_ptr =str + 1;
    char *ptr2;
    char *out;
    int len = 0;
    unsigned uc;
    unsigned uc2;

    /* not a string! */
    if (*str != '\"')
    {
        *ep = str;
        return 0;
    }

    while ((*end_ptr != '\"') && *end_ptr && ++len)
    {
        if (*end_ptr++ == '\\')
        {
            if (*end_ptr == '\0')
            {
                /* prevent buffer overflow when last input character is a backslash */
                return 0;
            }
            /* Skip escaped quotes. */
            end_ptr++;
        }
    }

    /* This is at most how long we need for the string, roughly. */
    out = (char*)cJSON_malloc(len + 1);
    if (!out)
    {
        return 0;
    }
    item->valuestring = out; /* assign here so out will be deleted during cJSON_Delete() later */
    item->type = cJSON_String;

    ptr = str + 1;
    ptr2 = out;
    /* loop through the string literal */
    while (ptr < end_ptr)
    {
        if (*ptr != '\\')
        {
            *ptr2++ = *ptr++;
        }
        /* escape sequence */
        else
        {
            ptr++;
            switch (*ptr)
            {
                case 'b':
                    *ptr2++ = '\b';
                    break;
                case 'f':
                    *ptr2++ = '\f';
                    break;
                case 'n':
                    *ptr2++ = '\n';
                    break;
                case 'r':
                    *ptr2++ = '\r';
                    break;
                case 't':
                    *ptr2++ = '\t';
                    break;
                case 'u':
                    /* transcode utf16 to utf8. See RFC2781 and RFC3629. */
                    uc = parse_hex4(ptr + 1); /* get the unicode char. */
                    ptr += 4;
                    if (ptr >= end_ptr)
                    {
                        /* invalid */
                        *ep = str;
                        return 0;
                    }
                    /* check for invalid. */
                    if (((uc >= 0xDC00) && (uc <= 0xDFFF)) || (uc == 0))
                    {
                        *ep = str;
                        return 0;
                    }

                    /* UTF16 surrogate pairs. */
                    if ((uc >= 0xD800) && (uc<=0xDBFF))
                    {
                        if ((ptr + 6) > end_ptr)
                        {
                            /* invalid */
                            *ep = str;
                            return 0;
                        }
                        if ((ptr[1] != '\\') || (ptr[2] != 'u'))
                        {
                            /* missing second-half of surrogate. */
                            *ep = str;
                            return 0;
                        }
                        uc2 = parse_hex4(ptr + 3);
                        ptr += 6; /* \uXXXX */
                        if ((uc2 < 0xDC00) || (uc2 > 0xDFFF))
                        {
                            /* invalid second-half of surrogate. */
                            *ep = str;
                            return 0;
                        }
                        /* calculate unicode codepoint from the surrogate pair */
                        uc = 0x10000 + (((uc & 0x3FF) << 10) | (uc2 & 0x3FF));
                    }

                    /* encode as UTF8
                     * takes at maximum 4 bytes to encode:
                     * 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx */
                    len = 4;
                    if (uc < 0x80)
                    {
                        /* normal ascii, encoding 0xxxxxxx */
                        len = 1;
                    }
                    else if (uc < 0x800)
                    {
                        /* two bytes, encoding 110xxxxx 10xxxxxx */
                        len = 2;
                    }
                    else if (uc < 0x10000)
                    {
                        /* three bytes, encoding 1110xxxx 10xxxxxx 10xxxxxx */
                        len = 3;
                    }
                    ptr2 += len;

                    switch (len) {
                        case 4:
                            /* 10xxxxxx */
                            *--ptr2 = ((uc | 0x80) & 0xBF);
                            uc >>= 6;
                        case 3:
                            /* 10xxxxxx */
                            *--ptr2 = ((uc | 0x80) & 0xBF);
                            uc >>= 6;
                        case 2:
                            /* 10xxxxxx */
                            *--ptr2 = ((uc | 0x80) & 0xBF);
                            uc >>= 6;
                        case 1:
                            /* depending on the length in bytes this determines the
                             * encoding ofthe first UTF8 byte */
                            *--ptr2 = (uc | firstByteMark[len]);
                    }
                    ptr2 += len;
                    break;
                default:
                    *ptr2++ = *ptr;
                    break;
            }
            ptr++;
        }
    }
    *ptr2 = '\0';
    if (*ptr == '\"')
    {
        ptr++;
    }

    return ptr;
}

/*将数据填充成可以打印出来的字符串*/
/* Render the cstring provided to an escaped version that can be printed. */
static char *print_string_ptr(const char *str, printbuffer *p)
{
    const char *ptr;
    char *ptr2;
    char *out;
    int len = 0;
    int flag = 0;
    unsigned char token;

    /* empty string */
    if (!str)
    {
        if (p)
        {
            out = ensure(p, 3);
        }
        else
        {
            out = (char*)cJSON_malloc(3);
        }
        if (!out)
        {
            return 0;
        }
        strcpy(out, "\"\"");

        return out;
    }

    /* set "flag" to 1 if something needs to be escaped */
    for (ptr = str; *ptr; ptr++)
    {
        flag |= (((*ptr > 0) && (*ptr < 32)) /* unprintable characters */
                || (*ptr == '\"') /* double quote */
                || (*ptr == '\\')) /* backslash */
            ? 1
            : 0;
    }
    /* no characters have to be escaped */
    if (!flag)
    {
        len = ptr - str;
        if (p)
        {
            out = ensure(p, len + 3);
        }
        else
        {
            out = (char*)cJSON_malloc(len + 3);
        }
        if (!out)
        {
            return 0;
        }

        ptr2 = out;
        *ptr2++ = '\"';
        strcpy(ptr2, str);
        ptr2[len] = '\"';
        ptr2[len + 1] = '\0';

        return out;
    }

    ptr = str;
    /* calculate additional space that is needed for escaping */
    while ((token = *ptr) && ++len)
    {
        if (strchr("\"\\\b\f\n\r\t", token))
        {
            len++; /* +1 for the backslash */
        }
        else if (token < 32)
        {
            len += 5; /* +5 for \uXXXX */
        }
        ptr++;
    }

    if (p)
    {
        out = ensure(p, len + 3);
    }
    else
    {
        out = (char*)cJSON_malloc(len + 3);
    }
    if (!out)
    {
        return 0;
    }

    ptr2 = out;
    ptr = str;
    *ptr2++ = '\"';
    /* copy the string */
    while (*ptr)
    {
        if (((unsigned char)*ptr > 31) && (*ptr != '\"') && (*ptr != '\\'))
        {
            /* normal character, copy */
            *ptr2++ = *ptr++;
        }
        else
        {
            /* character needs to be escaped */
            *ptr2++ = '\\';
            switch (token = *ptr++)
            {
                case '\\':
                    *ptr2++ = '\\';
                    break;
                case '\"':
                    *ptr2++ = '\"';
                    break;
                case '\b':
                    *ptr2++ = 'b';
                    break;
                case '\f':
                    *ptr2++ = 'f';
                    break;
                case '\n':
                    *ptr2++ = 'n';
                    break;
                case '\r':
                    *ptr2++ = 'r';
                    break;
                case '\t':
                    *ptr2++ = 't';
                    break;
                default:
                    /* escape and print as unicode codepoint */
                    sprintf(ptr2, "u%04x", token);
                    ptr2 += 5;
                    break;
            }
        }
    }
    *ptr2++ = '\"';
    *ptr2++ = '\0';

    return out;
}

//做了一层封装 以字符的形式填充
/* Invoke print_string_ptr (which is useful) on an item. */
static char *print_string(const cJSON *item, printbuffer *p)
{
    return print_string_ptr(item->valuestring, p);
}

/* Predeclare these prototypes. */
static const char *parse_value(cJSON *item, const char *value, const char **ep);
static char *print_value(const cJSON *item, int depth, int fmt, printbuffer *p);
static const char *parse_array(cJSON *item, const char *value, const char **ep);
static char *print_array(const cJSON *item, int depth, int fmt, printbuffer *p);
static const char *parse_object(cJSON *item, const char *value, const char **ep);
static char *print_object(const cJSON *item, int depth, int fmt, printbuffer *p);

/* Utility to jump whitespace and cr/lf */
static const char *skip(const char *in)
{//跳过空格
    while (in && *in && ((unsigned char)*in<=32))
    {
        in++;
    }

    return in;
}

/*解析对象，创建一个新的根并初始化，返回一个cJSON类型*/
/* Parse an object - create a new root, and populate. */
cJSON *cJSON_ParseWithOpts(const char *value, const char **return_parse_end, int require_null_terminated)
{
    const char *end = 0;
    /* use global error pointer if no specific one was given */
    const char **ep = return_parse_end ? return_parse_end : &global_ep;
    cJSON *c = cJSON_New_Item();
    *ep = 0;
    if (!c) /* memory fail */
    {
        return 0;
    }

    end = parse_value(c, skip(value), ep);
    if (!end)
    {
        /* parse failure. ep is set. */
        cJSON_Delete(c);
        return 0;
    }

    /* if we require null-terminated JSON without appended garbage, skip and then check for a null terminator */
    if (require_null_terminated)
    {
        end = skip(end);
        if (*end)
        {
            cJSON_Delete(c);
            *ep = end;
            return 0;
        }
    }
    if (return_parse_end)
    {
        *return_parse_end = end;
    }

    return c;
}

/*二次封装的下面3个函数*/
/* Default options for cJSON_Parse */
cJSON *cJSON_Parse(const char *value)
{
    return cJSON_ParseWithOpts(value, 0, 0);
}

/* Render a cJSON item/entity/structure to text. */
char *cJSON_Print(const cJSON *item)
{
    return print_value(item, 0, 1, 0);
}

char *cJSON_PrintUnformatted(const cJSON *item)
{
    return print_value(item, 0, 0, 0);
}

char *cJSON_PrintBuffered(const cJSON *item, int prebuffer, int fmt)
{
    printbuffer p;
    p.buffer = (char*)cJSON_malloc(prebuffer);
    p.length = prebuffer;
    p.offset = 0;

    return print_value(item, 0, fmt, &p);
}


/* Parser core - when encountering text, process appropriately. */
static const char *parse_value(cJSON *item, const char *value, const char **ep)
{
    if (!value)
    {
        /* Fail on null. */
        return 0;
    }

    /* parse the different types of values */
    if (!strncmp(value, "null", 4))
    {
        item->type = cJSON_NULL;
        return value + 4;
    }
    if (!strncmp(value, "false", 5))
    {
        item->type = cJSON_False;
        return value + 5;
    }
    if (!strncmp(value, "true", 4))
    {
        item->type = cJSON_True;
        item->valueint = 1;
        return value + 4;
    }
    if (*value == '\"')
    {
        return parse_string(item, value, ep);
    }
    if ((*value == '-') || ((*value >= '0') && (*value <= '9')))
    {
        return parse_number(item, value);
    }
    if (*value == '[')
    {
        return parse_array(item, value, ep);
    }
    if (*value == '{')
    {
        return parse_object(item, value, ep);
    }

    *ep=value;return 0; /* failure. */
}

/* Render a value to text. */
static char *print_value(const cJSON *item, int depth, int fmt, printbuffer *p)
{
    char *out = 0;

    if (!item)
    {
        return 0;
    }
    if (p)
    {
        switch ((item->type) & 0xFF)
        {
            case cJSON_NULL:
                out = ensure(p, 5);
                if (out)
                {
                    strcpy(out, "null");
                }
                break;
            case cJSON_False:
                out = ensure(p, 6);
                if (out)
                {
                    strcpy(out, "false");
                }
                break;
            case cJSON_True:
                out = ensure(p, 5);
                if (out)
                {
                    strcpy(out, "true");
                }
                break;
            case cJSON_Number:
                out = print_number(item, p);
                break;
            case cJSON_String:
                out = print_string(item, p);
                break;
            case cJSON_Array:
                out = print_array(item, depth, fmt, p);
                break;
            case cJSON_Object:
                out = print_object(item, depth, fmt, p);
                break;
        }
    }
    else
    {
        switch ((item->type) & 0xFF)
        {
            case cJSON_NULL:
                out = cJSON_strdup("null");
                break;
            case cJSON_False:
                out = cJSON_strdup("false");
                break;
            case cJSON_True:
                out = cJSON_strdup("true");
                break;
            case cJSON_Number:
                out = print_number(item, 0);
                break;
            case cJSON_String:
                out = print_string(item, 0);
                break;
            case cJSON_Array:
                out = print_array(item, depth, fmt, 0);
                break;
            case cJSON_Object:
                out = print_object(item, depth, fmt, 0);
                break;
        }
    }

    return out;
}

//解析数组
/* Build an array from input text. */
static const char *parse_array(cJSON *item,const char *value,const char **ep)
{
    cJSON *child;
    if (*value != '[')
    {
        /* not an array! */
        *ep = value;
        return 0;
    }

    item->type = cJSON_Array;
    value = skip(value + 1);
    if (*value == ']')
    {
        /* empty array. */
        return value + 1;
    }

    item->child = child = cJSON_New_Item();
    if (!item->child)
    {
        /* memory fail */
        return 0;
    }
    /* skip any spacing, get the value. */
    value = skip(parse_value(child, skip(value), ep));
    if (!value)
    {
        return 0;
    }

    /* loop through the comma separated array elements */
    while (*value == ',')
    {
        cJSON *new_item;
        if (!(new_item = cJSON_New_Item()))
        {
            /* memory fail */
            return 0;
        }
        /* add new item to end of the linked list */
        child->next = new_item;
        new_item->prev = child;
        child = new_item;

        /* go to the next comma */
        value = skip(parse_value(child, skip(value + 1), ep));
        if (!value)
        {
            /* memory fail */
            return 0;
        }
    }

    if (*value == ']')
    {
        /* end of array */
        return value + 1;
    }

    /* malformed. */
    *ep = value;

    return 0;
}

/* Render an array to text */
static char *print_array(const cJSON *item, int depth, int fmt, printbuffer *p)
{
    char **entries;
    char *out = 0;
    char *ptr;
    char *ret;
    int len = 5;
    cJSON *child = item->child;
    int numentries = 0;
    int i = 0;
    int fail = 0;
    size_t tmplen = 0;

    /* How many entries in the array? */
    while (child)
    {
        numentries++;
        child = child->next;
    }

    /* Explicitly handle numentries == 0 */
    if (!numentries)
    {
        if (p)
        {
            out = ensure(p, 3);
        }
        else
        {
            out = (char*)cJSON_malloc(3);
        }
        if (out)
        {
            strcpy(out,"[]");
        }

        return out;
    }

    if (p)
    {
        /* Compose the output array. */
        /* opening square bracket */
        i = p->offset;
        ptr = ensure(p, 1);
        if (!ptr)
        {
            return 0;
        }
        *ptr = '[';
        p->offset++;

        child = item->child;
        while (child && !fail)
        {
            print_value(child, depth + 1, fmt, p);
            p->offset = update(p);
            if (child->next)
            {
                len = fmt ? 2 : 1;
                ptr = ensure(p, len + 1);
                if (!ptr)
                {
                    return 0;
                }
                *ptr++ = ',';
                if(fmt)
                {
                    *ptr++ = ' ';
                }
                *ptr = 0;
                p->offset += len;
            }
            child = child->next;
        }
        ptr = ensure(p, 2);
        if (!ptr)
        {
            return 0;
        }
        *ptr++ = ']';
        *ptr = '\0';
        out = (p->buffer) + i;
    }
    else
    {
        /* Allocate an array to hold the pointers to all printed values */
        entries = (char**)cJSON_malloc(numentries * sizeof(char*));
        if (!entries)
        {
            return 0;
        }
        memset(entries, 0, numentries * sizeof(char*));

        /* Retrieve all the results: */
        child = item->child;
        while (child && !fail)
        {
            ret = print_value(child, depth + 1, fmt, 0);
            entries[i++] = ret;
            if (ret)
            {
                len += strlen(ret) + 2 + (fmt ? 1 : 0);
            }
            else
            {
                fail = 1;
            }
            child = child->next;
        }

        /* If we didn't fail, try to malloc the output string */
        if (!fail)
        {
            out = (char*)cJSON_malloc(len);
        }
        /* If that fails, we fail. */
        if (!out)
        {
            fail = 1;
        }

        /* Handle failure. */
        if (fail)
        {
            /* free all the entries in the array */
            for (i = 0; i < numentries; i++)
            {
                if (entries[i])
                {
                    cJSON_free(entries[i]);
                }
            }
            cJSON_free(entries);
            return 0;
        }

        /* Compose the output array. */
        *out='[';
        ptr = out + 1;
        *ptr = '\0';
        for (i = 0; i < numentries; i++)
        {
            tmplen = strlen(entries[i]);
            memcpy(ptr, entries[i], tmplen);
            ptr += tmplen;
            if (i != (numentries - 1))
            {
                *ptr++ = ',';
                if(fmt)
                {
                    *ptr++ = ' ';
                }
                *ptr = 0;
            }
            cJSON_free(entries[i]);
        }
        cJSON_free(entries);
        *ptr++ = ']';
        *ptr++ = '\0';
    }

    return out;
}
/*下面两个函数是解析对象和out一个字符串形式的对象！和上面两个API一样*/
/* Build an object from the text. */
static const char *parse_object(cJSON *item, const char *value, const char **ep)
{
    cJSON *child;
    if (*value != '{')
    {
        /* not an object! */
        *ep = value;
        return 0;
    }

    item->type = cJSON_Object;
    value = skip(value + 1);
    if (*value == '}')
    {
        /* empty object. */
        return value + 1;
    }

    child = cJSON_New_Item();
    item->child = child;
    if (!item->child)
    {
        return 0;
    }
    /* parse first key */
    value = skip(parse_string(child, skip(value), ep));
    if (!value)
    {
        return 0;
    }
    /* use string as key, not value */
    child->string = child->valuestring;
    child->valuestring = 0;

    if (*value != ':')
    {
        /* invalid object. */
        *ep = value;
        return 0;
    }
    /* skip any spacing, get the value. */
    value = skip(parse_value(child, skip(value + 1), ep));
    if (!value)
    {
        return 0;
    }

    while (*value == ',')
    {
        cJSON *new_item;
        if (!(new_item = cJSON_New_Item()))
        {
            /* memory fail */
            return 0;
        }
        /* add to linked list */
        child->next = new_item;
        new_item->prev = child;

        child = new_item;
        value = skip(parse_string(child, skip(value + 1), ep));
        if (!value)
        {
            return 0;
        }

        /* use string as key, not value */
        child->string = child->valuestring;
        child->valuestring = 0;

        if (*value != ':')
        {
            /* invalid object. */
            *ep = value;
            return 0;
        }
        /* skip any spacing, get the value. */
        value = skip(parse_value(child, skip(value + 1), ep));
        if (!value)
        {
            return 0;
        }
    }
    /* end of object */
    if (*value == '}')
    {
        return value + 1;
    }

    /* malformed */
    *ep = value;
    return 0;
}

/* Render an object to text. */
static char *print_object(const cJSON *item, int depth, int fmt, printbuffer *p)
{
    char **entries = 0;
    char **names = 0;
    char *out = 0;
    char *ptr;
    char *ret;
    char *str;
    int len = 7;
    int i = 0;
    int j;
    cJSON *child = item->child;
    int numentries = 0;
    int fail = 0;
    size_t tmplen = 0;

    /* Count the number of entries. */
    while (child)
    {
        numentries++;
        child = child->next;
    }

    /* Explicitly handle empty object case */
    if (!numentries)
    {
        if (p)
        {
            out = ensure(p, fmt ? depth + 4 : 3);
        }
        else
        {
            out = (char*)cJSON_malloc(fmt ? depth + 4 : 3);
        }
        if (!out)
        {
            return 0;
        }
        ptr = out;
        *ptr++ = '{';
        if (fmt) {
            *ptr++ = '\n';
            for (i = 0; i < depth; i++)
            {
                *ptr++ = '\t';
            }
        }
        *ptr++ = '}';
        *ptr++ = '\0';

        return out;
    }

    if (p)
    {
        /* Compose the output: */
        i = p->offset;
        len = fmt ? 2 : 1; /* fmt: {\n */
        ptr = ensure(p, len + 1);
        if (!ptr)
        {
            return 0;
        }

        *ptr++ = '{';
        if (fmt)
        {
            *ptr++ = '\n';
        }
        *ptr = '\0';
        p->offset += len;

        child = item->child;
        depth++;
        while (child)
        {
            if (fmt)
            {
                ptr = ensure(p, depth);
                if (!ptr)
                {
                    return 0;
                }
                for (j = 0; j < depth; j++)
                {
                    *ptr++ = '\t';
                }
                p->offset += depth;
            }

            /* print key */
            print_string_ptr(child->string, p);
            p->offset = update(p);

            len = fmt ? 2 : 1;
            ptr = ensure(p, len);
            if (!ptr)
            {
                return 0;
            }
            *ptr++ = ':';
            if (fmt)
            {
                *ptr++ = '\t';
            }
            p->offset+=len;

            /* print value */
            print_value(child, depth, fmt, p);
            p->offset = update(p);

            /* print comma if not last */
            len = (fmt ? 1 : 0) + (child->next ? 1 : 0);
            ptr = ensure(p, len + 1);
            if (!ptr)
            {
                return 0;
            }
            if (child->next)
            {
                *ptr++ = ',';
            }

            if (fmt)
            {
                *ptr++ = '\n';
            }
            *ptr = '\0';
            p->offset += len;

            child = child->next;
        }

        ptr = ensure(p, fmt ? (depth + 1) : 2);
        if (!ptr)
        {
            return 0;
        }
        if (fmt)
        {
            for (i = 0; i < (depth - 1); i++)
            {
                *ptr++ = '\t';
            }
        }
        *ptr++ = '}';
        *ptr = '\0';
        out = (p->buffer) + i;
    }
    else
    {
        /* Allocate space for the names and the objects */
        entries = (char**)cJSON_malloc(numentries * sizeof(char*));
        if (!entries)
        {
            return 0;
        }
        names = (char**)cJSON_malloc(numentries * sizeof(char*));
        if (!names)
        {
            cJSON_free(entries);
            return 0;
        }
        memset(entries,0, sizeof(char*) * numentries);
        memset(names, 0, sizeof(char*) * numentries);

        /* Collect all the results into our arrays: */
        child = item->child;
        depth++;
        if (fmt)
        {
            len += depth;
        }
        while (child && !fail)
        {
            names[i] = str = print_string_ptr(child->string, 0); /* print key */
            entries[i++] = ret = print_value(child, depth, fmt, 0);
            if (str && ret)
            {
                len += strlen(ret) + strlen(str) + 2 + (fmt ? 2 + depth : 0);
            }
            else
            {
                fail = 1;
            }
            child = child->next;
        }

        /* Try to allocate the output string */
        if (!fail)
        {
            out = (char*)cJSON_malloc(len);
        }
        if (!out)
        {
            fail = 1;
        }

        /* Handle failure */
        if (fail)
        {
            /* free all the printed keys and values */
            for (i = 0; i < numentries; i++)
            {
                if (names[i])
                {
                    cJSON_free(names[i]);
                }
                if (entries[i])
                {
                    cJSON_free(entries[i]);
                }
            }
            cJSON_free(names);
            cJSON_free(entries);
            return 0;
        }

        /* Compose the output: */
        *out = '{';
        ptr = out + 1;
        if (fmt)
        {
            *ptr++ = '\n';
        }
        *ptr = 0;
        for (i = 0; i < numentries; i++)
        {
            if (fmt)
            {
                for (j = 0; j < depth; j++)
                {
                    *ptr++='\t';
                }
            }
            tmplen = strlen(names[i]);
            memcpy(ptr, names[i], tmplen);
            ptr += tmplen;
            *ptr++ = ':';
            if (fmt)
            {
                *ptr++ = '\t';
            }
            strcpy(ptr, entries[i]);
            ptr += strlen(entries[i]);
            if (i != (numentries - 1))
            {
                *ptr++ = ',';
            }
            if (fmt)
            {
                *ptr++ = '\n';
            }
            *ptr = 0;
            cJSON_free(names[i]);
            cJSON_free(entries[i]);
        }

        cJSON_free(names);
        cJSON_free(entries);
        if (fmt)
        {
            for (i = 0; i < (depth - 1); i++)
            {
                *ptr++ = '\t';
            }
        }
        *ptr++ = '}';
        *ptr++ = '\0';
    }

    return out;
}

//返回节点的个数
/* Get Array size/item / object item. */
int    cJSON_GetArraySize(const cJSON *array)
{
    cJSON *c = array->child;
    int i = 0;
    while(c)
    {
        i++;
        c = c->next;
    }
    return i;
}

cJSON *cJSON_GetArrayItem(const cJSON *array, int item)
{
    cJSON *c = array ? array->child : 0;
    while (c && item > 0)
    {
        item--;
        c = c->next;
    }

    return c;
}

cJSON *cJSON_GetObjectItem(const cJSON *object, const char *string)
{
    cJSON *c = object ? object->child : 0;
    while (c && cJSON_strcasecmp(c->string, string))
    {
        c = c->next;
    }
    return c;
}

int cJSON_HasObjectItem(const cJSON *object,const char *string)
{
    return cJSON_GetObjectItem(object, string) ? 1 : 0;
}

/* Utility for array list handling. */
static void suffix_object(cJSON *prev, cJSON *item)
{
    prev->next = item;
    item->prev = prev;
}

/* Utility for handling references. */
static cJSON *create_reference(const cJSON *item)
{
    cJSON *ref = cJSON_New_Item();
    if (!ref)
    {
        return 0;
    }
    memcpy(ref, item, sizeof(cJSON));
    ref->string = 0;
    ref->type |= cJSON_IsReference;
    ref->next = ref->prev = 0;
    return ref;
}

//将item节点插入array链表        
/* Add item to array/object. */
void   cJSON_AddItemToArray(cJSON *array, cJSON *item)
{
    cJSON *c = array->child;
    if (!item)
    {
        return;
    }
    if (!c)
    {
        /* list is empty, start new one */
        array->child = item;
    }
    else
    {
        /* append to the end */
        while (c && c->next)
        {
            c = c->next;
        }
        suffix_object(c, item);
    }
}

//将字符串添加进对象
void   cJSON_AddItemToObject(cJSON *object, const char *string, cJSON *item)
{
    if (!item)
    {
        return;
    }

    /* free old key and set new one */
    if (item->string)
    {
        cJSON_free(item->string);
    }
    item->string = cJSON_strdup(string);

    cJSON_AddItemToArray(object,item);
}

/* Add an item to an object with constant string as key */
void   cJSON_AddItemToObjectCS(cJSON *object, const char *string, cJSON *item)
{
    if (!item)
    {
        return;
    }
    if (!(item->type & cJSON_StringIsConst) && item->string)
    {
        cJSON_free(item->string);
    }
    item->string = (char*)string;
    item->type |= cJSON_StringIsConst;
    cJSON_AddItemToArray(object, item);
}

void cJSON_AddItemReferenceToArray(cJSON *array, cJSON *item)
{
    cJSON_AddItemToArray(array, create_reference(item));
}

void cJSON_AddItemReferenceToObject(cJSON *object, const char *string, cJSON *item)
{
    cJSON_AddItemToObject(object, string, create_reference(item));
}

cJSON *cJSON_DetachItemFromArray(cJSON *array, int which)
{
    cJSON *c = array->child;
    while (c && (which > 0))
    {
        c = c->next;
        which--;
    }
    if (!c)
    {
        /* item doesn't exist */
        return 0;
    }
    if (c->prev)
    {
        /* not the first element */
        c->prev->next = c->next;
    }
    if (c->next)
    {
        c->next->prev = c->prev;
    }
    if (c==array->child)
    {
        array->child = c->next;
    }
    /* make sure the detached item doesn't point anywhere anymore */
    c->prev = c->next = 0;

    return c;
}

void cJSON_DeleteItemFromArray(cJSON *array, int which)
{
    cJSON_Delete(cJSON_DetachItemFromArray(array, which));
}

cJSON *cJSON_DetachItemFromObject(cJSON *object, const char *string)
{
    int i = 0;
    cJSON *c = object->child;
    while (c && cJSON_strcasecmp(c->string,string))
    {
        i++;
        c = c->next;
    }
    if (c)
    {
        return cJSON_DetachItemFromArray(object, i);
    }

    return 0;
}

void cJSON_DeleteItemFromObject(cJSON *object, const char *string)
{
    cJSON_Delete(cJSON_DetachItemFromObject(object, string));
}

/* Replace array/object items with new ones. */
void cJSON_InsertItemInArray(cJSON *array, int which, cJSON *newitem)
{
    cJSON *c = array->child;
    while (c && (which > 0))
    {
        c = c->next;
        which--;
    }
    if (!c)
    {
        cJSON_AddItemToArray(array, newitem);
        return;
    }
    newitem->next = c;
    newitem->prev = c->prev;
    c->prev = newitem;
    if (c == array->child)
    {
        array->child = newitem;
    }
    else
    {
        newitem->prev->next = newitem;
    }
}

void cJSON_ReplaceItemInArray(cJSON *array, int which, cJSON *newitem)
{
    cJSON *c = array->child;
    while (c && (which > 0))
    {
        c = c->next;
        which--;
    }
    if (!c)
    {
        return;
    }
    newitem->next = c->next;
    newitem->prev = c->prev;
    if (newitem->next)
    {
        newitem->next->prev = newitem;
    }
    if (c == array->child)
    {
        array->child = newitem;
    }
    else
    {
        newitem->prev->next = newitem;
    }
    c->next = c->prev = 0;
    cJSON_Delete(c);
}

void cJSON_ReplaceItemInObject(cJSON *object, const char *string, cJSON *newitem)
{
    int i = 0;
    cJSON *c = object->child;
    while(c && cJSON_strcasecmp(c->string, string))
    {
        i++;
        c = c->next;
    }
    if(c)
    {
        newitem->string = cJSON_strdup(string);
        cJSON_ReplaceItemInArray(object, i, newitem);
    }
}

/* Create basic types: */
cJSON *cJSON_CreateNull(void)
{
    cJSON *item = cJSON_New_Item();
    if(item)
    {
        item->type = cJSON_NULL;
    }

    return item;
}

cJSON *cJSON_CreateTrue(void)
{
    cJSON *item = cJSON_New_Item();
    if(item)
    {
        item->type = cJSON_True;
    }

    return item;
}

cJSON *cJSON_CreateFalse(void)
{
    cJSON *item = cJSON_New_Item();
    if(item)
    {
        item->type = cJSON_False;
    }

    return item;
}

cJSON *cJSON_CreateBool(int b)
{
    cJSON *item = cJSON_New_Item();
    if(item)
    {
        item->type = b ? cJSON_True : cJSON_False;
    }

    return item;
}

cJSON *cJSON_CreateNumber(double num)
{
    cJSON *item = cJSON_New_Item();
    if(item)
    {
        item->type = cJSON_Number;
        item->valuedouble = num;
        item->valueint = (int)num;
    }

    return item;
}

cJSON *cJSON_CreateString(const char *string)
{
    cJSON *item = cJSON_New_Item();
    if(item)
    {
        item->type = cJSON_String;
        item->valuestring = cJSON_strdup(string);
        if(!item->valuestring)
        {
            cJSON_Delete(item);
            return 0;
        }
    }

    return item;
}
//创建JSON数组
cJSON *cJSON_CreateArray(void)
{
    cJSON *item = cJSON_New_Item();
    if(item)
    {
        item->type=cJSON_Array;
    }

    return item;
}
//创建JSON对象
cJSON *cJSON_CreateObject(void)
{
    cJSON *item = cJSON_New_Item();
    if (item)
    {
        item->type = cJSON_Object;
    }

    return item;
}

/* Create Arrays: */
cJSON *cJSON_CreateIntArray(const int *numbers, int count)
{
    int i;
    cJSON *n = 0;
    cJSON *p = 0;
    cJSON *a = cJSON_CreateArray();
    for(i = 0; a && (i < count); i++)
    {
        n = cJSON_CreateNumber(numbers[i]);
        if (!n)
        {
            cJSON_Delete(a);
            return 0;
        }
        if(!i)
        {
            a->child = n;
        }
        else
        {
            suffix_object(p, n);
        }
        p = n;
    }

    return a;
}

cJSON *cJSON_CreateFloatArray(const float *numbers, int count)
{
    int i;
    cJSON *n = 0;
    cJSON *p = 0;
    cJSON *a = cJSON_CreateArray();
    for(i = 0; a && (i < count); i++)
    {
        n = cJSON_CreateNumber(numbers[i]);
        if(!n)
        {
            cJSON_Delete(a);
            return 0;
        }
        if(!i)
        {
            a->child = n;
        }
        else
        {
            suffix_object(p, n);
        }
        p = n;
    }

    return a;
}

cJSON *cJSON_CreateDoubleArray(const double *numbers, int count)
{
    int i;
    cJSON *n = 0;
    cJSON *p = 0;
    cJSON *a = cJSON_CreateArray();
    for(i = 0;a && (i < count); i++)
    {
        n = cJSON_CreateNumber(numbers[i]);
        if(!n)
        {
            cJSON_Delete(a);
            return 0;
        }
        if(!i)
        {
            a->child = n;
        }
        else
        {
            suffix_object(p, n);
        }
        p = n;
    }

    return a;
}

cJSON *cJSON_CreateStringArray(const char **strings, int count)
{
    int i;
    cJSON *n = 0;
    cJSON *p = 0;
    cJSON *a = cJSON_CreateArray();
    for (i = 0; a && (i < count); i++)
    {
        n = cJSON_CreateString(strings[i]);
        if(!n)
        {
            cJSON_Delete(a);
            return 0;
        }
        if(!i)
        {
            a->child = n;
        }
        else
        {
            suffix_object(p,n);
        }
        p = n;
    }

    return a;
}

/* Duplication */
cJSON *cJSON_Duplicate(const cJSON *item, int recurse)
{
    cJSON *newitem;
    cJSON *cptr;
    cJSON *nptr = 0;
    cJSON *newchild;

    /* Bail on bad ptr */
    if (!item)
    {
        return 0;
    }
    /* Create new item */
    newitem = cJSON_New_Item();
    if (!newitem)
    {
        return 0;
    }
    /* Copy over all vars */
    newitem->type = item->type & (~cJSON_IsReference);
    newitem->valueint = item->valueint;
    newitem->valuedouble = item->valuedouble;
    if (item->valuestring)
    {
        newitem->valuestring = cJSON_strdup(item->valuestring);
        if (!newitem->valuestring)
        {
            cJSON_Delete(newitem);
            return 0;
        }
    }
    if (item->string)
    {
        newitem->string = cJSON_strdup(item->string);
        if (!newitem->string)
        {
            cJSON_Delete(newitem);
            return 0;
        }
    }
    /* If non-recursive, then we're done! */
    if (!recurse)
    {
        return newitem;
    }
    /* Walk the ->next chain for the child. */
    cptr = item->child;
    while (cptr)
    {
        newchild = cJSON_Duplicate(cptr, 1); /* Duplicate (with recurse) each item in the ->next chain */
        if (!newchild)
        {
            cJSON_Delete(newitem);
            return 0;
        }
        if (nptr)
        {
            /* If newitem->child already set, then crosswire ->prev and ->next and move on */
            nptr->next = newchild;
            newchild->prev = nptr;
            nptr = newchild;
        }
        else
        {
            /* Set newitem->child and move to it */
            newitem->child = newchild; nptr = newchild;
        }
        cptr = cptr->next;
    }

    return newitem;
}

void cJSON_Minify(char *json)
{
    char *into = json;
    while (*json)
    {
        if (*json == ' ')
        {
            json++;
        }
        else if (*json == '\t')
        {
            /* Whitespace characters. */
            json++;
        }
        else if (*json == '\r')
        {
            json++;
        }
        else if (*json=='\n')
        {
            json++;
        }
        else if ((*json == '/') && (json[1] == '/'))
        {
            /* double-slash comments, to end of line. */
            while (*json && (*json != '\n'))
            {
                json++;
            }
        }
        else if ((*json == '/') && (json[1] == '*'))
        {
            /* multiline comments. */
            while (*json && !((*json == '*') && (json[1] == '/')))
            {
                json++;
            }
            json += 2;
        }
        else if (*json == '\"')
        {
            /* string literals, which are \" sensitive. */
            *into++ = *json++;
            while (*json && (*json != '\"'))
            {
                if (*json == '\\')
                {
                    *into++=*json++;
                }
                *into++ = *json++;
            }
            *into++ = *json++;
        }
        else
        {
            /* All other characters. */
            *into++ = *json++;
        }
    }

    /* and null-terminate. */
    *into = '\0';
}