+ /* Set timeout. */
+ port->timeouts.ReadIntervalTimeout = 0;
+ port->timeouts.ReadTotalTimeoutConstant = timeout;
+ if (SetCommTimeouts(port->hdl, &port->timeouts) == 0)
+ RETURN_FAIL("SetCommTimeouts() failed");
+
+ /* Start read. */
+ if (ReadFile(port->hdl, buf, count, NULL, &port->read_ovl) == 0) {
+ if (GetLastError() == ERROR_IO_PENDING) {
+ DEBUG("Waiting for read to complete");
+ GetOverlappedResult(port->hdl, &port->read_ovl, &bytes_read, TRUE);
+ DEBUG("Read completed, %d/%d bytes read", bytes_read, count);
+ RETURN_VALUE("%d", bytes_read);
+ } else {
+ RETURN_FAIL("ReadFile() failed");
+ }
+ } else {
+ DEBUG("Read completed immediately");
+ RETURN_VALUE("%d", count);
+ }
+#else
+ size_t bytes_read = 0;
+ unsigned char *ptr = (unsigned char *) buf;
+ struct timeval start, delta, now, end = {0, 0};
+ fd_set fds;
+ int result;
+
+ if (timeout) {
+ /* Get time at start of operation. */
+ gettimeofday(&start, NULL);
+ /* Define duration of timeout. */
+ delta.tv_sec = timeout / 1000;
+ delta.tv_usec = (timeout % 1000) * 1000;
+ /* Calculate time at which we should give up. */
+ timeradd(&start, &delta, &end);
+ }
+
+ /* Loop until we have the requested number of bytes. */
+ while (bytes_read < count)
+ {
+ /* Wait until data is available. */
+ FD_ZERO(&fds);
+ FD_SET(port->fd, &fds);
+ if (timeout) {
+ gettimeofday(&now, NULL);
+ if (timercmp(&now, &end, >))
+ /* Timeout has expired. */
+ RETURN_VALUE("%d", bytes_read);
+ timersub(&end, &now, &delta);
+ }
+ result = select(port->fd + 1, &fds, NULL, NULL, timeout ? &delta : NULL);
+ if (result < 0) {
+ if (errno == EINTR) {
+ DEBUG("select() call was interrupted, repeating");
+ continue;
+ } else {
+ RETURN_FAIL("select() failed");
+ }
+ } else if (result == 0) {
+ DEBUG("read timed out");
+ RETURN_VALUE("%d", bytes_read);
+ }
+
+ /* Do read. */
+ result = read(port->fd, ptr, count - bytes_read);
+
+ if (result < 0) {
+ if (errno == EAGAIN)
+ /* This shouldn't happen because we did a select() first, but handle anyway. */
+ continue;
+ else
+ /* This is an actual failure. */
+ RETURN_FAIL("read() failed");
+ }
+
+ bytes_read += result;
+ ptr += result;
+ }
+
+ RETURN_VALUE("%d", bytes_read);
+#endif
+}
+
+enum sp_return sp_nonblocking_read(struct sp_port *port, void *buf, size_t count)
+{
+ TRACE("%p, %p, %d", port, buf, count);
+
+ CHECK_OPEN_PORT();
+
+ if (!buf)
+ RETURN_ERROR(SP_ERR_ARG, "Null buffer");
+
+ DEBUG("Reading up to %d bytes from port %s", count, port->name);
+
+#ifdef _WIN32
+ DWORD bytes_read;
+
+ /* Set timeout. */
+ port->timeouts.ReadIntervalTimeout = MAXDWORD;
+ port->timeouts.ReadTotalTimeoutConstant = 0;
+ if (SetCommTimeouts(port->hdl, &port->timeouts) == 0)
+ RETURN_FAIL("SetCommTimeouts() failed");
+
+ /* Do read. */
+ if (ReadFile(port->hdl, buf, count, NULL, &port->read_ovl) == 0)
+ RETURN_FAIL("ReadFile() failed");
+
+ /* Get number of bytes read. */
+ GetOverlappedResult(port->hdl, &port->read_ovl, &bytes_read, TRUE);
+
+ RETURN_VALUE("%d", bytes_read);