// A persistent read function.
static ssize_t read_r(int fd, void *buf, size_t count, size_t ms)
{
double tMax = ms / 1000.0; // convert to seconds
PosixTimer t;
int r;
unsigned int total = 0;
while (total < count) {
r = read(fd, ((unsigned char *)buf) + total, count - total);
// did something seriously go wrong?
if (r < 0 && errno != EINTR) {
__dbg(string("PosixSerial: failed to read: ") + string(strerror(errno)));
throw PosixSerial::ReadFailure();
} else if (r > 0) {
// progress!
total += r;
t.start(); // restart the timer
}
// are we out of time?
if (ms > 0 && t.elapsed() > tMax) {
__dbg(string("PosixSerial: read timed out"));
throw PosixSerial::ReadTimeout();
}
}
return total;
}
// A persistent write function.
static ssize_t write_r(int fd, const void *buf, size_t count, size_t ms)
{
double tMax = ms / 1000.0; // convert to seconds
PosixTimer t;
int r;
unsigned int written = 0;
while (written < count) {
r = write(fd, ((const unsigned char *)buf) + written, count - written);
// did something seriously go wrong?
if (r < 0 && errno != EINTR) {
__dbg(string("PosixSerial: failed to write: ") + string(strerror(errno)));
throw PosixSerial::WriteFailure();
} else if (r > 0) {
// progress!
written += r;
t.start(); // restart the timer
}
// are we out of time?
if (ms > 0 && t.elapsed() > tMax) {
__dbg(string("PosixSerial: write timed out"));
throw PosixSerial::WriteTimeout();
}
}
return written;
}
