cJSON简单编程
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 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