int FileTransferProtocol::recvFilename(net::Socket &s, string &filename) {
int bytes_received;
// First, receive the filename size (3 bytes ascii-encoded unsigned integer)
char buf[3];
bytes_received = s.recv(buf, 3, 0);
if (bytes_received == SOCKET_ERROR || bytes_received != 3) {
onTransferError("Could not receive filename header size!");
return -1;
}
// Try to parse what we have received
size_t len;
if (EOF == sscanf_s(buf, "%3lu", &len)) {
onTransferError("Could not parse filename header size!");
return -1;
}
// Finally, allocate a string and receive the filename
char *nameBuf = (char*)malloc(len + 1);
nameBuf[len] = '\0';
bytes_received = s.recv(nameBuf, len, 0);
if (bytes_received == SOCKET_ERROR || bytes_received != len) {
free(nameBuf);
onTransferError("Could not receive filename header!");
}
filename = string(nameBuf);
free(nameBuf);
return 0;
}
int FileTransferProtocol::waitForAck(net::Socket &s, string errmsg) {
char ackbuf[4] = " "; // Either ACK or ERR
int bytes_received = s.recv(ackbuf, 3, 0);
if (bytes_received == SOCKET_ERROR || bytes_received != 3 || strcmp(ackbuf, "ERR") == 0) {
onTransferError(errmsg);
return -1;
}
return 0;
}
int FileTransferProtocol::recvCommand(net::Socket &s, char &command) {
char d;
int bytes_received;
bytes_received = s.recv(&d, 1, 0);
if (bytes_received == SOCKET_ERROR || bytes_received != 1) {
onTransferError("Could not receive direction from client!");
return -1;
}
if (d != 'D' && d != 'U' && d != 'L' && d != 'Q') {
onTransferError("Client sent invalid direction!");
return -1;
}
command = d;
return 0;
}
size_t StreamSocketReceiver::receiveHeader(net::Socket &s)
{
char buf[20];
size_t bytes_received;
if (bytes_received = s.recv(buf, 20) != 20) {
throw IncompleteReceiveException(bytes_received, 20);
}
// Try to parse length of payload in header
size_t len;
if (EOF == sscanf_s(buf, "%20lu", &len)) {
throw UnparseableHeaderException(buf);
}
return len;
}
void StreamSocketReceiver::receivePayload(net::Socket &s, ostream &stream, size_t len)
{
void *buf = malloc(this->packet_size);
size_t bytes_read = 0;
while (bytes_read < len) {
size_t exp_bytes = min(this->packet_size, len - bytes_read);
size_t bytes_recv = s.recv((char*)buf, exp_bytes);
if (bytes_recv != exp_bytes) {
free(buf);
throw IncompleteReceiveException(bytes_read + bytes_recv, len);
}
bytes_read += bytes_recv;
stream.write((char*)buf, bytes_recv);
}
free(buf);
}