c语言简单json库

写在前面

用c语言实现的一个简单json库，极其轻量
仅1个四百多行源码的源文件，和1个头文件
支持对象、数组、数值、字符串类型
github仓库

头文件

对主要的json API的声明

#ifndef ARCOJSON_ARCOJSON_H
#define ARCOJSON_ARCOJSON_H#define VERSION v0.1
enum json_type{json_type_empty,json_type_object,json_type_array,json_type_string,json_type_long
};typedef struct arco_json{enum json_type type;int child_num;int seq;char* key;void* value;struct arco_json* parent;struct arco_json* next;
}arco_json;/*** function: new_json_object* 功能:创建一个json对象*/
arco_json* new_json_object();/*** function: new_json_array* 功能:创建一个json数组*/
arco_json* new_json_array();/*** function:* 功能:创建一个json, value是字符串*/
arco_json* new_json_string(char* value);/*** function: new_json_long* 功能:创建一个json, value是long类型的字符串* 说明:为了代码简洁, 仅使用long来表示数值*/
arco_json* new_json_long(long value);/*** function: get_json_type* 功能:返回json的类型*/
int get_json_type(arco_json* json);/*** function: json_object_add* 功能:给json对象添加键值对*/
int json_object_add(arco_json* json, char* key, arco_json* j_add);/*** function: json_array_add* 功能:给json数组添加对象*/
int json_array_add(arco_json* json, arco_json* j_add);/*** function: json_to_string* 功能:json对象转json格式字符串*/
char* json_to_string(arco_json* json);/*** function: string_to_json* 功能:json格式字符串转json对象*/
arco_json* string_to_json(char* str);/*** function: get_string_from_object* 功能:通过key获取字符串类型的value*/
char* get_string_from_object(arco_json* json, char* key);/*** function: get_long_from_object* 功能:通过key获取数值类型的value*/
long get_long_from_object(arco_json* json, char* key);/*** function: get_object_from_object* 功能:通过key获取object类型的value*/
arco_json* get_object_from_object(arco_json* json, char* key);/*** function: get_object_from_array* 功能:获取json array的第idx个对象(从0开始*/
arco_json* get_object_from_array(arco_json* json, int idx);#endif //ARCOJSON_ARCOJSON_H

源代码

//
// Created by arco on 2023/8/19.
//
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "arcojson.h"int g_json_char_num = 0;
char* g_json_str = NULL;int init_new_json(arco_json* json, int json_type)
{json->type = json_type;json->child_num = 0;json->seq = 0;json->key = NULL;json->value = NULL;json->next = NULL;
}arco_json* new_json_object()
{arco_json* json = malloc(sizeof(arco_json));init_new_json(json, json_type_object);return json;
}arco_json* new_json_array()
{arco_json* json = malloc(sizeof(arco_json));init_new_json(json, json_type_array);return json;
}arco_json* new_json_string(char* value)
{// 分配内存arco_json* json = malloc(sizeof(arco_json));init_new_json(json, json_type_string);json->value = (char*) malloc(strlen(value) + 1);memcpy(json->value, value, strlen(value) + 1);return json;
}arco_json* new_json_long(long value)
{// 分配内存arco_json* json = malloc(sizeof(arco_json));init_new_json(json, json_type_long);json->value = (long*) malloc(sizeof(long));*(long*) json->value = value;return json;
}arco_json* new_json_empty()
{// 分配内存arco_json* json = malloc(sizeof(arco_json));init_new_json(json, json_type_empty);return json;
}int get_json_type(arco_json* json)
{if (json != NULL) return json->type;else return -1;
}int json_object_add(arco_json* json, char* key, arco_json* j_add)
{if (json->type != json_type_object) {printf("json type isn't object, can't add kv\n");return -1;}int i;// if cur json has none valueif (json->value == NULL) {json->value = j_add;j_add->parent = json;j_add->key = malloc(strlen(key) + 1);memcpy(j_add->key, key, strlen(key) + 1);json->child_num++;}else {arco_json* arco = json->value;for (i = 0; i < json->child_num - 1; i++) {arco = arco->next;}j_add->key = malloc(strlen(key) + 1);memcpy(j_add->key, key, strlen(key) + 1);arco->next = j_add;j_add->parent = arco->parent;json->child_num++;}return 0;
}int json_array_add(arco_json* json, arco_json* j_add)
{if (json->type != json_type_array) {printf("json type isn't array, can't add object\n");return -1;}int i;// if cur json has none valueif (json->value == NULL) {json->value = j_add;json->child_num++;}else {arco_json* arco = json->value;for (i = 0; i < json->child_num - 1; i++) {arco = arco->next;}arco->next = j_add;j_add->parent = arco->parent;json->child_num++;}return 0;
}typedef void (*deal_callback) (char*, ...);void json_depth_expand(arco_json* json, int depth, deal_callback callback)
{if (get_json_type(json) == json_type_array) {if (json->key != NULL && depth > 0)callback("\"%s\":", json->key);callback("[");if (json->value != NULL)json_depth_expand(json->value, depth + 1, callback);}if (get_json_type(json) == json_type_object) {if (json->key != NULL && depth > 0)callback("\"%s\":", json->key);callback("{");if (json->value != NULL)json_depth_expand(json->value, depth + 1, callback);}if (json->type == json_type_string) {callback("\"%s\":", json->key);callback("\"%s\"", (char*) json->value);if (json->next != NULL) callback(",");}if (json->type == json_type_long) {callback("\"%s\":", json->key);callback("%d", *(long*) json->value);if (json->next != NULL) callback(",");}if (get_json_type(json) == json_type_array) {callback("]");if (json->next != NULL && depth > 0) callback(",");}if (get_json_type(json) == json_type_object) {callback("}");if (json->next != NULL && depth > 0) callback(",");}// 横向搜索if (json->next != NULL && depth > 0) {json_depth_expand(json->next, depth, callback);}
}void calculate_callback(char* fmt, ...)
{va_list args;va_start(args, fmt);char str[64];vsprintf(str, fmt, args);g_json_char_num += (int) strlen(str);va_end(args);
}void tostring_callback(char* fmt, ...)
{va_list args;va_start(args, fmt);char str[64];vsprintf(str, fmt, args);strcat(g_json_str, str);va_end(args);
}int calculate_json_str_length(arco_json* json)
{g_json_char_num = 0;json_depth_expand(json, 0, calculate_callback);return g_json_char_num;
}char* json_to_string(arco_json* json)
{int size = calculate_json_str_length(json);g_json_str = malloc(size + 1);memset(g_json_str, '\0', size + 1);json_depth_expand(json, 0, tostring_callback);char* json_str = malloc(strlen(g_json_str) + 1);memcpy(json_str, g_json_str, strlen(g_json_str) + 1);free(g_json_str);g_json_str = NULL;return json_str;
}char* str_get_here_to_there(char* str, int position, char c)
{int i, size = 1;char* dst = NULL;for (i = position; i < strlen(str); i++) {if (str[i] != c) size++;else break;}dst = malloc(sizeof(char) * size);for (i = position; i < strlen(str); i++) {if (str[i] != c) dst[i - position] = str[i];else {dst[i - position] = '\0';return dst;}}return NULL;
}// 返回值是解析的数值的字符串长度(需要跳过的长度
int parse_num_value(char* str, void* value)
{int i, start = 0, val_len = 0;long rate = 1;long* num_val = malloc(sizeof(long));char arr[16];memset(arr, '\0', sizeof(arr));if (str[0] == '-') start = 1;val_len += start;for (i = start; i < strlen(str) && i < sizeof(arr) - 1; i++) {if (str[i] < '0' || str[i] > '9') break;arr[i - start] = str[i];val_len++;}for (i = strlen(arr) - 1; i >= 0; i--) {*num_val += (arr[i] - '0') * rate;rate *= 10;}if (start) *num_val *= -1;*(long*) value = *num_val;return val_len;
}arco_json* string_to_json(char* str)
{int i, str_len = (int) strlen(str), need_new = 0;int yh_flag = 0, value_flag = 0;arco_json* json = new_json_empty();arco_json* p_json = json;for (i = 0; i < str_len; i++) {/*** 紧随{或[后的第一个json还没有new出来*/if (need_new) {arco_json* j_tmp = new_json_empty();p_json->value = j_tmp;j_tmp->parent = p_json;p_json = p_json->value;need_new = 0;}/*** 截取第1-2个引号之间的值作为key, 如果有第3-4个引号那就作为value*/if (str[i] == '"') {yh_flag++;if (yh_flag == 1) {p_json->key = str_get_here_to_there(str, i + 1, '"');}else if (yh_flag == 2) {}else if (yh_flag == 3) {p_json->value = str_get_here_to_there(str, i + 1, '"');p_json->type = json_type_string;}else if (yh_flag == 4) {yh_flag = 0;}}/*** 处理冒号后紧随的第一个*/if (value_flag) {if ((str[i] >= '0' && str[i] <= '9') || str[i] == '-') {p_json->type = json_type_long;p_json->value = (long*)malloc(sizeof(long));i += parse_num_value(&str[i], p_json->value);yh_flag = 0;}value_flag = 0;}if (str[i] == ':') {value_flag = 1;}if (str[i] == '{') {yh_flag = 0;need_new = 1;p_json->type = json_type_object;}if (str[i] == '[') {yh_flag = 0;need_new = 1;p_json->type = json_type_array;}if (str[i] == ',') {// 创建一个空json, 挂到当前json的nextarco_json* j_tmp = new_json_empty();j_tmp->seq = p_json->seq + 1;p_json->next = j_tmp;// 拷贝上级jsonj_tmp->parent = p_json->parent;// 如果是第1个确保当前json的上级的value指向正确if (p_json->seq == 0) {arco_json* q_json = p_json->parent;q_json->value = p_json;}// 移动当前jsonp_json = p_json->next;}if (str[i] == '}' || str[i] == ']') {arco_json* j_tmp = p_json->parent;p_json = j_tmp;}}return json;
}char* get_string_from_object(arco_json* json, char* key)
{if (json == NULL) return NULL;if (json->type != json_type_object) return NULL;if (json->value == NULL) return NULL;arco_json* p_json = json->value;while (p_json != NULL) {if (p_json->type == json_type_string) {if (strcmp((char*) p_json->key, key) == 0) {size_t length = strlen((char*) p_json->value);char* res = malloc(sizeof(length + 1));memcpy(res, p_json->value, length + 1);return res;}}p_json = p_json->next;}return NULL;
}long get_long_from_object(arco_json* json, char* key)
{if (json == NULL) return -1;if (json->type != json_type_object) return -1;if (json->value == NULL) return -1;arco_json* p_json = json->value;while (p_json != NULL) {if (p_json->type == json_type_long) {if (strcmp((char*) p_json->key, key) == 0) {long res = *(long*) p_json->value;return res;}}p_json = p_json->next;}return -1;
}arco_json* get_object_from_object(arco_json* json, char* key)
{if (json == NULL) return NULL;if (json->type != json_type_object) return NULL;if (json->value == NULL) return NULL;arco_json* p_json = json->value;while (p_json != NULL) {if (p_json->type == json_type_object) {if (strcmp((char*) p_json->key, key) == 0) {arco_json* res = malloc(sizeof(arco_json));memcpy(res, p_json, sizeof(arco_json));return res;}}p_json = p_json->next;}return NULL;
}arco_json* get_object_from_array(arco_json* json, int idx)
{if (json == NULL) return NULL;if (json->type != json_type_array) return NULL;if (json->value == NULL) return NULL;int i = 0;arco_json* p_json = json->value;while (p_json != NULL) {if (p_json->type == json_type_object) {if (i == idx) {arco_json* res = malloc(sizeof(arco_json));memcpy(res, p_json, sizeof(arco_json));return res;}}p_json = p_json->next;i++;}return NULL;
}

使用示例

请直接看最下面的main函数

//
// Created by arco on 2023/9/3.
//
#include <string.h>
#include <stdio.h>
#include "arcojson.h"/*** test arco json usage*/
void create_json_object_test()
{arco_json* json = new_json_object();json_object_add(json, "key0", new_json_string("value0"));arco_json* json1 = new_json_object();json_object_add(json1, "key1.0", new_json_string("value1.0"));json_object_add(json, "key1", json1);arco_json* json2 = new_json_object();arco_json* json20 = new_json_object();json_object_add(json20, "key2.0.1", new_json_string("value2.0.1"));json_object_add(json2, "key2.0", json20);json_object_add(json, "key2", json2);printf("create_json_obj:%s\n", json_to_string(json));
}void create_json_object_test_long()
{arco_json* json = new_json_object();json_object_add(json, "key0", new_json_long(100));arco_json* json1 = new_json_object();json_object_add(json1, "key1.0", new_json_long(-1));json_object_add(json, "key1", json1);arco_json* json2 = new_json_object();arco_json* json20 = new_json_object();json_object_add(json20, "key2.0.1", new_json_long(-1234567));json_object_add(json20, "key2.0.2", new_json_string("value2.0.2"));json_object_add(json2, "key2.0", json20);json_object_add(json, "key2", json2);printf("create_json_obj_num:%s\n", json_to_string(json));
}void create_json_array_test()
{arco_json* json = new_json_array();arco_json* json0 = new_json_object();json_object_add(json0, "key0", new_json_string("value0"));arco_json* json1 = new_json_object();json_object_add(json1, "key1", new_json_string("value1"));arco_json* json2 = new_json_object();arco_json* json20 = new_json_object();json_object_add(json20, "key2.0", new_json_string("value2.0"));json_object_add(json2, "key2", json20);json_array_add(json, json0);json_array_add(json, json1);json_array_add(json, json2);printf("create_json_arr:%s\n", json_to_string(json));
}void create_json_mixed_test()
{arco_json* json = new_json_object();arco_json* j_o0 = new_json_object();json_object_add(j_o0, "ok0", new_json_string("oval0"));arco_json* j_a1 = new_json_array();arco_json* j_o10 = new_json_object();json_object_add(j_o10, "ok10", new_json_string("oval10"));arco_json* j_o11 = new_json_object();json_object_add(j_o11, "ok11", new_json_string("oval11"));json_object_add(j_o11, "ok12", new_json_string("oval12"));json_array_add(j_a1, j_o10);json_array_add(j_a1, j_o11);arco_json* j_o2 = new_json_object();arco_json* j_o20 = new_json_object();json_object_add(j_o20, "ok20", new_json_string("oval20"));json_object_add(j_o20, "ok21", new_json_string("oval21"));json_object_add(j_o20, "ok22", new_json_string("oval22"));json_object_add(j_o2, "ok2", j_o20);json_object_add(json, "obj_1", j_o0);json_object_add(json, "arr_1", j_a1);json_object_add(json, "obj_2", j_o2);printf("create_json_mix:%s\n", json_to_string(json));
}void create_json_null_test()
{arco_json* json_o = new_json_object();arco_json* json_a = new_json_array();printf("create_json_nul:%s  %s\n", json_to_string(json_o), json_to_string(json_a));
}void str_to_json_object_test()
{char str[] = "{\"key0\":\"value0\",\"key1\":{\"key1.0\":\"value1.0\"},\"key2\":{\"key2.0\":{\"key2.0.1\":\"value2.0.1\"}}}";arco_json* json = string_to_json(str);printf("str_to_json_obj:%s\n", json_to_string(json));
}void str_to_json_object_test_long()
{char str[] = "{\"key0\":100,\"key1\":{\"key1.0\":-1},\"key2\":{\"key2.0\":{\"key2.0.1\":-1234567,\"key2.0.2\":\"value2.0.2\"}}}";arco_json* json = string_to_json(str);printf("str_to_json_obj_num:%s\n", json_to_string(json));
}void str_to_json_array_test()
{char str[] = "[{\"key0\":\"value0\"},{\"key1\":\"value1\"},{\"key2\":{\"key2.0\":\"value2.0\"}}]";arco_json* json = string_to_json(str);printf("str_to_json_arr:%s\n", json_to_string(json));
}void str_to_json_mixed_test()
{char str[] = "{\"obj_1\":{\"ok0\":\"oval0\"},\"arr_1\":[{\"ok10\":\"oval10\"},{\"ok11\":\"oval11\",\"ok12\":\"oval12\"}],\"obj_2\":{\"ok2\":{\"ok20\":\"oval20\",\"ok21\":\"oval21\",\"ok22\":\"oval22\"}}}";arco_json* json = string_to_json(str);printf("str_to_json_mix:%s\n", json_to_string(json));
}void str_to_json_null_test()
{char str[] = "{}";arco_json* json = string_to_json(str);char str2[] = "[]";arco_json* json2 = string_to_json(str2);printf("str_to_json_null:%s  %s\n", json_to_string(json), json_to_string(json2));
}void json_depth_expand_print(arco_json* json, int depth)
{
//    printf("depth=%d\n", depth);if (get_json_type(json) == json_type_array) {if (json->key != NULL && depth > 0) printf("\"%s\":", json->key);printf("[");json_depth_expand_print(json->value, depth + 1);}if (get_json_type(json) == json_type_object) {if (json->key != NULL && depth > 0) printf("\"%s\":", json->key);printf("{");json_depth_expand_print(json->value, depth + 1);}if (json->type == json_type_string) {printf("\"%s\":", json->key);printf("\"%s\"", (char*) json->value);if (json->next != NULL) printf(",");}if (json->type == json_type_long) {printf("\"%s\":", json->key);printf("%d", *(int*) json->value);if (json->next != NULL) printf(",");}if (json->type == json_type_empty) {printf("tmd empty\n");}if (get_json_type(json) == json_type_array) {printf("]");if (json->next != NULL && depth > 0) printf(",");}if (get_json_type(json) == json_type_object) {printf("}");if (json->next != NULL && depth > 0) printf(",");}// 横向搜索if (json->next != NULL && depth > 0) {json_depth_expand_print(json->next, depth);}
}void get_json_value_test()
{arco_json* json = new_json_array();arco_json* json0 = new_json_object();json_object_add(json0, "key00", new_json_long(123));json_object_add(json0, "key01", new_json_string("value01"));json_object_add(json0, "key02", new_json_string("value02"));arco_json* json1 = new_json_object();arco_json* json10 = new_json_object();json_object_add(json10, "key10", new_json_string("value10"));json_object_add(json10, "key11", new_json_long(1234567));json_object_add(json1, "key1", json10);json_array_add(json, json0);json_array_add(json, json1);printf("get_json_value_test:%s\n", json_to_string(json));arco_json* get_obj_by_idx = get_object_from_array(json, 1);printf("get_obj_by_idx:%s\n", json_to_string(get_obj_by_idx));arco_json* get_obj_by_key = get_object_from_object(get_obj_by_idx, "key1");printf("get_obj_by_key:%s\n", json_to_string(get_obj_by_key));char* get_str = get_string_from_object(get_obj_by_key, "key10");printf("get_str_value:%s\n", get_str);long get_long = get_long_from_object(get_obj_by_key, "key11");printf("get_str_value:%ld\n", get_long);}int main()
{// 创建json对象示例create_json_object_test();str_to_json_object_test();printf("\n");// 创建带数值的json对象示例create_json_object_test_long();str_to_json_object_test_long();printf("\n");// 创建json数组示例create_json_array_test();str_to_json_array_test();printf("\n");// 对象和数组混合示例create_json_mixed_test();str_to_json_mixed_test();printf("\n");// null情况示例create_json_null_test();str_to_json_null_test();printf("\n");// json对象获取值示例(数组 对象 字符串 数值get_json_value_test();return 0;
}

编译：arcojson.c arcojson.h example.c三个文件放在同一目录下，然后 gcc arcojson.c example.c -o test
运行： ./test