sample

char buf[1000];
recev(buf, 1000); // buf is filled magically.

char * p = buf;
uint16_t ptype = *(uint16_t*)(p);

struct AResponse
{
	uint16_t ptype;
	bool is_successful;
	// ... variables.
};

switch (ptype)
{
	case 51:
		AResponse * res;
		res = *(AResponse*)(p);

		if (res->is_successful)

	break;
}