Create key operator/manipulation functions for timespecs, add them to new unix-timespec.h helper header.

include/serial/impl/unix-timespec.h

@@ -0,0 +1,122 @@
+/*!
+ * \file serial/impl/unit-timespec.h
+ * \author  Mike Purvis <mpurvis@clearpathrobotics.com>
+ * \version 0.1
+ *
+ * \section LICENSE
+ *
+ * The MIT License
+ *
+ * Copyright (c) 2013 William Woodall
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * \section DESCRIPTION
+ *
+ * Provides helper and operator functions for concisely and reliably handling
+ * timespec instances on unix platforms.
+ */
+
+#ifndef SERIAL_IMPL_UNIX_TIMESPEC_H
+#define SERIAL_IMPL_UNIX_TIMESPEC_H
+
+/*! Smooth over platform variances in getting an accurate timespec
+ * representing the present moment. */ 
+static inline void
+get_time_now (struct timespec &time)
+{
+# ifdef __MACH__ // OS X does not have clock_gettime, use clock_get_time
+  clock_serv_t cclock;
+  mach_timespec_t mts;
+  host_get_clock_service(mach_host_self(), CALENDAR_CLOCK, &cclock);
+  clock_get_time(cclock, &mts);
+  mach_port_deallocate(mach_task_self(), cclock);
+  time.tv_sec = mts.tv_sec;
+  time.tv_nsec = mts.tv_nsec;
+# else
+  clock_gettime(CLOCK_REALTIME, &time);
+# endif
+}
+
+/*! Simple function to normalize the tv_nsec field to [0..1e9), carrying
+ * the remainder into the tv_sec field. This will not protect against the
+ * possibility of an overflow in the nsec field--proceed with caution. */
+static inline void
+normalize(struct timespec* ts) {
+  while (ts->tv_nsec < 0) {
+    ts->tv_nsec += 1e9;
+    ts->tv_sec -= 1;
+  }
+  while (ts->tv_nsec >= 1e9) {
+    ts->tv_nsec -= 1e9;
+    ts->tv_sec += 1;
+  }
+}
+
+/*! Return a timespec which is the sum of two other timespecs. */
+static inline struct timespec
+operator+ (const struct timespec &a, const struct timespec &b) {
+  struct timespec result = { a.tv_sec + b.tv_sec,
+                             a.tv_nsec + b.tv_nsec };
+  normalize(&result);
+  return result;
+}
+
+/*! Return a timespec which is the difference of two other timespecs. */
+static inline struct timespec
+operator- (const struct timespec &a, const struct timespec &b) {
+  struct timespec result = { a.tv_sec - b.tv_sec,
+                             a.tv_nsec - b.tv_nsec };
+  normalize(&result);
+  return result;
+}
+
+/*! Return a timespec which is a multiplication of a timespec and a positive
+ * integer. No overflow protection-- not suitable for multiplications with 
+ * large carries, eg a <1s timespec multiplied by a large enough integer 
+ * that the result is muliple seconds. */
+static inline struct timespec
+operator* (const struct timespec &ts, const size_t mul) {
+  struct timespec result = { ts.tv_sec * mul,
+                             ts.tv_nsec * mul };
+  normalize(&result);
+  return result;
+}
+
+/*! Return whichever of two timespecs represents the shortest or most
+ * negative duration. */
+static inline struct timespec
+min (const struct timespec &a, const struct timespec &b) {
+  if (a.tv_sec < b.tv_sec
+     || (a.tv_sec == b.tv_sec && a.tv_nsec < b.tv_nsec)) {
+    return a;
+  } else {
+    return b;
+  }
+}
+
+/*! Return a timespec set from a provided number of milliseconds. */
+static struct timespec
+timespec_from_millis(const size_t millis) {
+  struct timespec result = { 0, millis * 1000000 };
+  normalize(&result);
+  return result;
+}
+
+#endif

include/serial/impl/unix.h

@@ -122,7 +122,7 @@ public:
   getPort () const;
 
   void
-  setTimeout (Timeout &timeout);
+  setTimeout (const Timeout &timeout);
 
   Timeout
   getTimeout () const;
@@ -180,7 +180,13 @@ private:
   bool xonxoff_;
   bool rtscts_;
 
-  Timeout timeout_;         // Timeout for read operations
+  Timeout timeout_;         // Timeouts for read/write operations
+  struct timespec inter_byte_timeout_;
+  struct timespec read_timeout_constant_;
+  struct timespec read_timeout_multiplier_;
+  struct timespec write_timeout_constant_;
+  struct timespec write_timeout_multiplier_;
+
   unsigned long baudrate_;    // Baudrate
 
   parity_t parity_;           // Parity

src/impl/unix.cc

@@ -27,6 +27,7 @@
 #endif
 
 #include "serial/impl/unix.h"
+#include "serial/impl/unix-timespec.h"
 
 #ifndef TIOCINQ
 #ifdef FIONREAD
@@ -396,74 +397,6 @@ Serial::SerialImpl::available ()
   }
 }
 
-inline void
-get_time_now (struct timespec &time)
-{
-# ifdef __MACH__ // OS X does not have clock_gettime, use clock_get_time
-  clock_serv_t cclock;
-  mach_timespec_t mts;
-  host_get_clock_service(mach_host_self(), CALENDAR_CLOCK, &cclock);
-  clock_get_time(cclock, &mts);
-  mach_port_deallocate(mach_task_self(), cclock);
-  time.tv_sec = mts.tv_sec;
-  time.tv_nsec = mts.tv_nsec;
-# else
-  clock_gettime(CLOCK_REALTIME, &time);
-# endif
-}
-
-inline void
-diff_timespec (timespec &start, timespec &end, timespec &result) {
-  if (start.tv_sec > end.tv_sec) {
-    throw SerialException ("Timetravel, start time later than end time.");
-  }
-  result.tv_sec = end.tv_sec - start.tv_sec;
-  result.tv_nsec = end.tv_nsec - start.tv_nsec;
-  if (result.tv_nsec < 0) {
-    result.tv_nsec = 1e9 - result.tv_nsec;
-    result.tv_sec -= 1;
-  }
-}
-
-/*! Simple function to normalize the tv_nsec field to [0..1e9), carrying
- * the remainder into the tv_sec field. */
-void normalize(timespec* ts) {
-  while (ts->tv_nsec < 0) {
-    ts->tv_nsec += 1e9;
-    ts->tv_sec -= 1;
-  }
-  while (ts->tv_nsec >= 1e9) {
-    ts->tv_nsec -= 1e9;
-    ts->tv_sec += 1;
-  }
-}
-
-inline struct timespec
-operator+ (const struct timespec &a, const struct timespec &b) {
-  struct timespec result = { a.tv_sec + b.tv_sec,
-                             a.tv_nsec + b.tv_nsec };
-  normalize(&result);
-  return result;
-}
-
-inline struct timespec
-operator- (const struct timespec &a, const struct timespec &b) {
-  struct timespec result = { a.tv_sec - b.tv_sec,
-                             a.tv_nsec - b.tv_nsec };
-  normalize(&result);
-  return result;
-}
-
-inline struct timespec
-min (const struct timespec &a, const struct timespec &b) {
-  if (a.tv_sec < b.tv_sec
-     || (a.tv_sec == b.tv_sec && a.tv_nsec < b.tv_nsec)) {
-    return a;
-  } else {
-    return b;
-  }
-}
-
 size_t
 Serial::SerialImpl::read (uint8_t *buf, size_t size)
 {
@@ -611,8 +544,7 @@ Serial::SerialImpl::write (const uint8_t *data, size_t length)
     // Calculate difference and update the structure
     get_time_now(end);
     // Calculate the time select took
-    struct timespec diff;
-    diff_timespec(start, end, diff);
+    struct timespec diff(end - start);
     // Update the timeout
     if (timeout.tv_sec <= diff.tv_sec) {
       timeout.tv_sec = 0;