+ if ((lflag & ICANON) == 0) {
+ int m = cc[VMIN];
+ long t = cc[VTIME];
+ struct timeval stime, timecopy;
+ int x;
+
+ /*
+ * Check each of the four combinations.
+ * (m > 0 && t == 0) is the normal read case.
+ * It should be fairly efficient, so we check that and its
+ * companion case (m == 0 && t == 0) first.
+ * For the other two cases, we compute the target sleep time
+ * into slp.
+ */
+ if (t == 0) {
+ if (rblen < m)
+ goto sleep;
+ if (rblen > 0)
+ goto read;
+
+ /* m, t and rblen are all 0. 0 is enough input. */
+ splx(s);
+ return (0);
+ }
+ t *= 100000; /* time in us */
+#define diff(t1, t2) (((t1).tv_sec - (t2).tv_sec) * 1000000 + \
+ ((t1).tv_usec - (t2).tv_usec))
+ if (m > 0) {
+ if (rblen <= 0)
+ goto sleep;
+ if (rblen >= m)
+ goto read;
+ x = splclock();
+ timecopy = time;
+ splx(x);
+ if (!has_stime) {
+ /* first character, start timer */
+ has_stime = 1;
+ stime = timecopy;
+ slp = t;
+ } else if (rblen > last_cc) {
+ /* got a character, restart timer */
+ stime = timecopy;
+ slp = t;
+ } else {
+ /* nothing, check expiration */
+ slp = t - diff(timecopy, stime);
+ if (slp <= 0)
+ goto read;
+ }
+ last_cc = rblen;
+ } else { /* m == 0 */
+ if (rblen > 0)
+ goto read;
+ x = splclock();
+ timecopy = time;
+ splx(x);
+ if (!has_stime) {
+ has_stime = 1;
+ stime = timecopy;
+ slp = t;
+ } else {
+ slp = t - diff(timecopy, stime);
+ if (slp <= 0) {
+ /* Timed out, but 0 is enough input. */
+ splx(s);
+ return (0);
+ }
+ }
+ }
+#undef diff
+ /*
+ * Rounding down may make us wake up just short
+ * of the target, so we round up.
+ * The formula is ceiling(slp * hz/1000000).
+ * 32-bit arithmetic is enough for hz < 169.
+ * XXX see hzto() for how to avoid overflow if hz
+ * is large (divide by `tick' and/or arrange to
+ * use hzto() if hz is large).
+ */
+ slp = (long) (((u_long)slp * hz) + 999999) / 1000000;
+ goto sleep;
+ }
+ if (rblen <= 0) {
projects / unix-history / blobdiff