Smart json import/update into internal structure

json.c

#include <json-c/json.h>
#include <stdio.h>
#include <string.h>
#include <stddef.h>

typedef enum{
	diff_none,
	diff_type,
	diff_value,
	diff_removed,
	diff_added,
	diff_length,
} diff_kind_t;

typedef struct Node{
	const char* name;
	struct Node *attributes;
	size_t size,count;
	void*  data_p;
	/* primitives attributes */
	char*  string_p;
	double*number_p;
	size_t at;
	
} Node;
#define ATTR(...) attributes:(Node[]){ __VA_ARGS__, {(char*)(~0)}}
#define countof(W) (sizeof(W)/sizeof(W[0]))
typedef struct{
	char name[32];
	double x,y,z,age[3];
}satellite_t;
typedef struct{
	char name[32];
	char support[32];
	char manufacturer[32];
	double id;
}terminal_t;

void model_dump(Node*m,int depth){
	for(int i=0;i<depth;i++)fprintf(stderr,"  ");

	if(m->name)fprintf(stderr,"'%s':",m->name);

	if(m->attributes){/* tree */
		fprintf(stderr,"<obj/list>count:%zu,size:%zu,data:%p\n",m->count,m->size,m->data_p);
		for(Node*i=m->attributes;i->name!=(char*)~0;i++)
			model_dump(i,depth+1);
	}else{/* primitive */
		if(m->string_p)
			fprintf(stderr,"@%p\n",m->string_p);
		if(m->number_p)
			fprintf(stderr,"@%p\n",m->number_p);
		else
			fprintf(stderr,"@%zu\n",m->at);
	}
}

void json_dump(json_object *node,int depth){
	json_object_iter it;
	printf("\n");
	for(int i=0;i<depth;i++)printf("  ");
	printf("%s:",json_type_to_name(json_object_get_type(node)));
	switch(json_object_get_type(node)){
		case json_type_null   :printf("null");break;
		case json_type_boolean:printf("%s",json_object_get_boolean(node)?"true":"false");break;
		case json_type_double :printf("%g",json_object_get_double(node));break;
		case json_type_int    :printf("%i",json_object_get_int(node));break;
		case json_type_string :printf("'%s'",json_object_get_string(node));break;
		case json_type_object :json_object_object_foreachC(node,it)printf("(%s)",(json_dump(it.val,depth+1),it.key));break;
		case json_type_array  :for(int i=0;i<json_object_array_length(node);i++)json_dump(json_object_array_get_idx(node,i),depth+1);break;
	}
	if(depth==0)printf("\n");
}

int json_diff(json_object *node,json_object *node_b,char*path){
	json_object_iter it;
	json_object*attr;
	int ret;
	if(json_object_get_type(node) != json_object_get_type(node))return diff_type;
	switch(json_object_get_type(node)){
		case json_type_int    :
			if(json_object_get_int(node) != json_object_get_int(node_b))
				return diff_value;
			break;
		case json_type_double :
			if(json_object_get_double(node) != json_object_get_double(node_b))
				return diff_value;
			break;
		case json_type_boolean:
			if(json_object_get_boolean(node) != json_object_get_boolean(node_b))
				return diff_value;
			break;
		case json_type_string :
			if(strcmp(json_object_get_string(node),json_object_get_string(node_b)))
				return diff_value;
			break;
		case json_type_object :
			json_object_object_foreachC(node_b,it){
				sprintf(path,".%s",it.key);
				if(!json_object_object_get_ex(node,it.key,&attr))
					return diff_removed;
			}
			json_object_object_foreachC(node,it){
				sprintf(path,".%s",it.key);
				if(!json_object_object_get_ex(node_b,it.key,&attr))
					return diff_added;
				if((ret=json_diff(it.val,attr,path+strlen(path)))!=0)
					return ret;
			}
			break; 
		case json_type_array  :
			if(json_object_array_length(node)!=json_object_array_length(node_b))return diff_length;
			for(int i=0;i<json_object_array_length(node);i++){
				sprintf(path,"[%i]",i);
				if((ret=json_diff(json_object_array_get_idx(node,i),json_object_array_get_idx(node_b,i),path+strlen(path))))return ret;
			}
			break;
	}
	return diff_none;
}

int model_load_json(Node*m, json_object*node, int depth){
	json_object_iter it;
	printf("\n");
	for(int i=0;i<depth;i++)printf("  ");
	printf("%s:",json_type_to_name(json_object_get_type(node)));
	switch(json_object_get_type(node)){
		case json_type_null   :printf("null");break;
		case json_type_boolean:printf("%s",json_object_get_boolean(node)?"true":"false");break;
		case json_type_double :printf("%g",json_object_get_double(node));break;
		case json_type_int    :printf("%i",json_object_get_int(node));break;
		case json_type_string :printf("'%s'",json_object_get_string(node));break;
		case json_type_object :json_object_object_foreachC(node,it)printf("(%s)",(model_load_json(m,it.val,depth+1),it.key));break;
		case json_type_array  :for(int i=0;i<json_object_array_length(node);i++)model_load_json(m,json_object_array_get_idx(node,i),depth+1);break;
	}
	if(depth==0)printf("\n");
	return 0;
}

satellite_t sat[32];
terminal_t term[128];
double version;

int main(int argc, char** argv){
	json_object*obj_a = json_object_from_file(argv[1]);
	
	Node model = {ATTR(
		{"version",number_p:&version},
		{"satellites",data_p:sat,size:sizeof(sat[0]),count:countof(sat),ATTR(
			{"name",at:offsetof(satellite_t,name)},
			{"x",at:offsetof(satellite_t,x)},
			{"y",at:offsetof(satellite_t,y)},
			{"z",at:offsetof(satellite_t,z)}
		)},
		{"terminals",ATTR(
			{"name",at:offsetof(terminal_t,name)},
			{"info",ATTR(
				{"support",at:offsetof(terminal_t,support)},
				{"manufacturer",at:offsetof(terminal_t,manufacturer)}
			)},
			{"id",at:offsetof(terminal_t,name)}
		)}
	)};
	/*
	json_object*obj_b = json_object_from_file(argv[2]);
	char jpath[2048];
	diff_kind_t d = json_diff(obj_a,obj_b,jpath);
	if(d != diff_none){
		printf("json_diff kind:%i at:%s\n", d, jpath);
	}
	
	json_dump(obj_a,0);
	json_dump(obj_b,0);
	*/
	model_dump(&model,0);
	model_load_json(&model,obj_a,0);
	
	return 0;
}