HW12/socket_wrapper.h

#ifndef _SOCKET_WRAPPER_H_
#define _SOCKET_WRAPPER_H_
#include <stdint.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>


static const size_t DEFAULT_BUF_SIZE = 4096;
static const size_t MINIMUM_BUF_SIZE = 1024;

enum{
    RES_OK = 0,
    RES_ERR = 1,
    RES_USR_ERR = 2
};

#pragma pack(push,1)
struct ReadOp{
    uint16_t file_url_size;/* strlen(data) */
    uint16_t padding0;
};
struct TransferResult{
    int16_t res;
    int16_t error_msg_size;
    int64_t file_size;
    int32_t err_number; /*errno*/
};
#pragma pack(pop)

/**
 * find buffer size from sock
 * thread safe
*/
int getBufferSizeFrom(int sock);

/**
 * return -2 if timeout occur.
 * otherwise, implement equal to 'recv'.
 * `timeout` unit is second.
 * thread safe
*/
ssize_t timeout_recv(int fd,void * buf,size_t n,int timeout);
/**
 * recieve data to buf until all bytes.
 * thread safe
*/
ssize_t recv_until_byte(int fd,void * buf, size_t n,int timeout);

/**
 * find sockaddr by hostname
 * it perform like `gethostbyname`
 * hostname could not be greater than _SC_HOST_NAME_MAX.
 * return 0 on success, otherwise return ecode.
 * ecode can be converted to string by `gai_strerror`. 
*/
int getsockaddrbyname(int domain,int type, int protocol, const char * hostname_str, struct sockaddr * retaddr);
#endif