Move timing routines to separate file.

[libserialport.git] / timing.c

diff --git a/timing.c b/timing.c
new file mode 100644 (file)
index 0000000..957f676
--- /dev/null
+++ b/timing.c
@@ -0,0 +1,176 @@
+/*
+ * This file is part of the libserialport project.
+ *
+ * Copyright (C) 2019 Martin Ling <martin-libserialport@earth.li>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include "libserialport.h"
+#include "libserialport_internal.h"
+
+SP_PRIV void time_get(struct time *time)
+{
+#ifdef _WIN32
+       LARGE_INTEGER count;
+       QueryPerformanceCounter(&count);
+       time->ticks = count.QuadPart;
+#elif defined(HAVE_CLOCK_GETTIME)
+       struct timespec ts;
+       if (clock_gettime(CLOCK_MONOTONIC, &ts) == -1)
+               clock_gettime(CLOCK_REALTIME, &ts);
+       time->tv.tv_sec = ts.tv_sec;
+       time->tv.tv_usec = ts.tv_nsec / 1000;
+#elif defined(__APPLE__)
+       mach_timebase_info_data_t info;
+       mach_timebase_info(&info);
+       uint64_t ticks = mach_absolute_time();
+       uint64_t ns = (ticks * info.numer) / info.denom;
+       time->tv.tv_sec = ns / 1000000000;
+       time->tv.tv_usec = (ns % 1000000000) / 1000;
+#else
+       gettimeofday(&time->tv, NULL);
+#endif
+}
+
+SP_PRIV void time_set_ms(struct time *time, unsigned int ms)
+{
+#ifdef _WIN32
+       LARGE_INTEGER frequency;
+       QueryPerformanceFrequency(&frequency);
+       time->ticks = ms * (frequency.QuadPart / 1000);
+#else
+       time->tv.tv_sec = ms / 1000;
+       time->tv.tv_usec = (ms % 1000) * 1000;
+#endif
+}
+
+SP_PRIV void time_add(const struct time *a,
+               const struct time *b, struct time *result)
+{
+#ifdef _WIN32
+       result->ticks = a->ticks + b->ticks;
+#else
+       timeradd(&a->tv, &b->tv, &result->tv);
+#endif
+}
+
+SP_PRIV void time_sub(const struct time *a,
+               const struct time *b, struct time *result)
+{
+#ifdef _WIN32
+       result->ticks = a->ticks - b->ticks;
+#else
+       timersub(&a->tv, &b->tv, &result->tv);
+#endif
+}
+
+SP_PRIV bool time_greater(const struct time *a, const struct time *b)
+{
+#ifdef _WIN32
+       return (a->ticks > b->ticks);
+#else
+       return timercmp(&a->tv, &b->tv, >);
+#endif
+}
+
+SP_PRIV void time_as_timeval(const struct time *time, struct timeval *tv)
+{
+#ifdef _WIN32
+       LARGE_INTEGER frequency;
+       QueryPerformanceFrequency(&frequency);
+       tv->tv_sec = time->ticks / frequency.QuadPart;
+       tv->tv_usec = (time->ticks % frequency.QuadPart) /
+               (frequency.QuadPart / 1000000);
+#else
+       *tv = time->tv;
+#endif
+}
+
+SP_PRIV unsigned int time_as_ms(const struct time *time)
+{
+#ifdef _WIN32
+       LARGE_INTEGER frequency;
+       QueryPerformanceFrequency(&frequency);
+       return time->ticks / (frequency.QuadPart / 1000);
+#else
+       return time->tv.tv_sec * 1000 + time->tv.tv_usec / 1000;
+#endif
+}
+
+SP_PRIV void timeout_start(struct timeout *timeout, unsigned int timeout_ms)
+{
+       timeout->ms = timeout_ms;
+
+       /* Get time at start of operation. */
+       time_get(&timeout->start);
+       /* Define duration of timeout. */
+       time_set_ms(&timeout->delta, timeout_ms);
+       /* Calculate time at which we should give up. */
+       time_add(&timeout->start, &timeout->delta, &timeout->end);
+       /* Disable limit unless timeout_limit() called. */
+       timeout->limit_ms = 0;
+       /* First blocking call has not yet been made. */
+       timeout->calls_started = false;
+}
+
+SP_PRIV void timeout_limit(struct timeout *timeout, unsigned int limit_ms)
+{
+       timeout->limit_ms = limit_ms;
+       timeout->overflow = (timeout->ms > timeout->limit_ms);
+       time_set_ms(&timeout->delta_max, timeout->limit_ms);
+}
+
+SP_PRIV bool timeout_check(struct timeout *timeout)
+{
+       if (!timeout->calls_started)
+               return false;
+
+       if (timeout->ms == 0)
+               return false;
+
+       time_get(&timeout->now);
+       time_sub(&timeout->end, &timeout->now, &timeout->delta);
+       if (timeout->limit_ms)
+               if ((timeout->overflow = time_greater(&timeout->delta, &timeout->delta_max)))
+                       timeout->delta = timeout->delta_max;
+
+       return time_greater(&timeout->now, &timeout->end);
+}
+
+SP_PRIV void timeout_update(struct timeout *timeout)
+{
+       timeout->calls_started = true;
+}
+
+#ifndef _WIN32
+SP_PRIV struct timeval *timeout_timeval(struct timeout *timeout)
+{
+       if (timeout->ms == 0)
+               return NULL;
+
+       time_as_timeval(&timeout->delta, &timeout->delta_tv);
+
+       return &timeout->delta_tv;
+}
+#endif
+
+SP_PRIV unsigned int timeout_remaining_ms(struct timeout *timeout)
+{
+       if (timeout->limit_ms && timeout->overflow)
+               return timeout->limit_ms;
+       else
+               return time_as_ms(&timeout->delta);
+}