util: add a timespec helper

Copied from Weston, upon Daniel's suggestion

Signed-off-by: Lionel Landwerlin <[email protected]>
Suggested-by: Daniel Stone <[email protected]>
Reviewed-by: Daniel Stone <[email protected]>

5 files changed, 673 insertions, 0 deletions

diff --git a/src/util/Makefile.sources b/src/util/Makefile.sources
index ad8c56d3d1b..cbbf5126875 100644
--- a/src/util/Makefile.sources
+++ b/src/util/Makefile.sources
@@ -60,6 +60,7 @@ MESA_UTIL_FILES := \
 	strtod.c \
 	strtod.h \
 	texcompress_rgtc_tmp.h \
+	timespec.h \
 	u_atomic.c \
 	u_atomic.h \
 	u_dynarray.h \
diff --git a/src/util/meson.build b/src/util/meson.build
index 67b6981d8b5..8aa7af921e1 100644
--- a/src/util/meson.build
+++ b/src/util/meson.build
@@ -82,6 +82,7 @@ files_mesa_util = files(
   'strtod.c',
   'strtod.h',
   'texcompress_rgtc_tmp.h',
+  'timespec.h',
   'u_atomic.c',
   'u_atomic.h',
   'u_dynarray.h',
@@ -218,6 +219,7 @@ if with_tests
   subdir('tests/fast_urem_by_const')
   subdir('tests/hash_table')
   subdir('tests/string_buffer')
+  subdir('tests/timespec')
   subdir('tests/vma')
   subdir('tests/set')
 endif
diff --git a/src/util/tests/timespec/meson.build b/src/util/tests/timespec/meson.build
new file mode 100644
index 00000000000..aa801bee188
--- /dev/null
+++ b/src/util/tests/timespec/meson.build
@@ -0,0 +1,31 @@
+# Copyright © 2019 Intel Corporation
+
+# 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.
+
+test(
+  'timespec',
+  executable(
+    'timespec_test',
+    'timespec_test.cpp',
+    dependencies : [dep_thread, dep_dl, idep_gtest],
+    include_directories : inc_common,
+    link_with : [libmesa_util],
+  ),
+  suite : ['util'],
+)
diff --git a/src/util/tests/timespec/timespec_test.cpp b/src/util/tests/timespec/timespec_test.cpp
new file mode 100644
index 00000000000..51a57c507f2
--- /dev/null
+++ b/src/util/tests/timespec/timespec_test.cpp
@@ -0,0 +1,309 @@
+/*
+ * Copyright © 2016 Collabora, Ltd.
+ *
+ * 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 (including the
+ * next paragraph) 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.
+ */
+
+#include <gtest/gtest.h>
+
+#include "util/timespec.h"
+
+TEST(timespec_test, timespec_add)
+{
+   struct timespec a, b, r;
+
+   a.tv_sec = 1;
+   a.tv_nsec = NSEC_PER_SEC - 1;
+   b.tv_sec = 1;
+   b.tv_nsec = 2;
+   timespec_add(&r, &a, &b);
+   EXPECT_EQ(r.tv_sec, 3);
+   EXPECT_EQ(r.tv_nsec, 1);
+}
+
+TEST(timespec_test, timespec_sub)
+{
+   struct timespec a, b, r;
+
+   a.tv_sec = 1;
+   a.tv_nsec = 1;
+   b.tv_sec = 0;
+   b.tv_nsec = 2;
+   timespec_sub(&r, &a, &b);
+   EXPECT_EQ(r.tv_sec, 0);
+   EXPECT_EQ(r.tv_nsec, NSEC_PER_SEC - 1);
+}
+
+TEST(timespec_test, timespec_to_nsec)
+{
+   struct timespec a;
+
+   a.tv_sec = 4;
+   a.tv_nsec = 4;
+   EXPECT_EQ(timespec_to_nsec(&a), (NSEC_PER_SEC * 4ULL) + 4);
+}
+
+TEST(timespec_test, timespec_to_usec)
+{
+   struct timespec a;
+
+   a.tv_sec = 4;
+   a.tv_nsec = 4000;
+   EXPECT_EQ(timespec_to_usec(&a), (4000000ULL) + 4);
+}
+
+TEST(timespec_test, timespec_to_msec)
+{
+   struct timespec a;
+
+   a.tv_sec = 4;
+   a.tv_nsec = 4000000;
+   EXPECT_EQ(timespec_to_msec(&a), (4000ULL) + 4);
+}
+
+TEST(timespec_test, timespec_to_proto)
+{
+   struct timespec a;
+   uint32_t tv_sec_hi;
+   uint32_t tv_sec_lo;
+   uint32_t tv_nsec;
+
+   a.tv_sec = 0;
+   a.tv_nsec = 0;
+   timespec_to_proto(&a, &tv_sec_hi, &tv_sec_lo, &tv_nsec);
+   EXPECT_EQ(0, tv_sec_hi);
+   EXPECT_EQ(0, tv_sec_lo);
+   EXPECT_EQ(0, tv_nsec);
+
+   a.tv_sec = 1234;
+   a.tv_nsec = NSEC_PER_SEC - 1;
+   timespec_to_proto(&a, &tv_sec_hi, &tv_sec_lo, &tv_nsec);
+   EXPECT_EQ(0, tv_sec_hi);
+   EXPECT_EQ(1234, tv_sec_lo);
+   EXPECT_EQ(NSEC_PER_SEC - 1, tv_nsec);
+
+   a.tv_sec = (time_t)0x7000123470005678LL;
+   a.tv_nsec = 1;
+   timespec_to_proto(&a, &tv_sec_hi, &tv_sec_lo, &tv_nsec);
+   EXPECT_EQ((uint64_t)a.tv_sec >> 32, tv_sec_hi);
+   EXPECT_EQ(0x70005678, tv_sec_lo);
+   EXPECT_EQ(1, tv_nsec);
+}
+
+TEST(timespec_test, millihz_to_nsec)
+{
+   EXPECT_EQ(millihz_to_nsec(60000), 16666666);
+}
+
+TEST(timespec_test, timespec_add_nsec)
+{
+   struct timespec a, r;
+
+   a.tv_sec = 0;
+   a.tv_nsec = NSEC_PER_SEC - 1;
+   timespec_add_nsec(&r, &a, 1);
+   EXPECT_EQ(1, r.tv_sec);
+   EXPECT_EQ(0, r.tv_nsec);
+
+   timespec_add_nsec(&r, &a, 2);
+   EXPECT_EQ(1, r.tv_sec);
+   EXPECT_EQ(1, r.tv_nsec);
+
+   timespec_add_nsec(&r, &a, (NSEC_PER_SEC * 2ULL));
+   EXPECT_EQ(2, r.tv_sec);
+   EXPECT_EQ(NSEC_PER_SEC - 1, r.tv_nsec);
+
+   timespec_add_nsec(&r, &a, (NSEC_PER_SEC * 2ULL) + 2);
+   EXPECT_EQ(r.tv_sec, 3);
+   EXPECT_EQ(r.tv_nsec, 1);
+
+   a.tv_sec = 1;
+   a.tv_nsec = 1;
+   timespec_add_nsec(&r, &a, -2);
+   EXPECT_EQ(r.tv_sec, 0);
+   EXPECT_EQ(r.tv_nsec, NSEC_PER_SEC - 1);
+
+   a.tv_nsec = 0;
+   timespec_add_nsec(&r, &a, -NSEC_PER_SEC);
+   EXPECT_EQ(0, r.tv_sec);
+   EXPECT_EQ(0, r.tv_nsec);
+
+   a.tv_nsec = 0;
+   timespec_add_nsec(&r, &a, -NSEC_PER_SEC + 1);
+   EXPECT_EQ(0, r.tv_sec);
+   EXPECT_EQ(1, r.tv_nsec);
+
+   a.tv_nsec = 50;
+   timespec_add_nsec(&r, &a, (-NSEC_PER_SEC * 10ULL));
+   EXPECT_EQ(-9, r.tv_sec);
+   EXPECT_EQ(50, r.tv_nsec);
+
+   r.tv_sec = 4;
+   r.tv_nsec = 0;
+   timespec_add_nsec(&r, &r, NSEC_PER_SEC + 10ULL);
+   EXPECT_EQ(5, r.tv_sec);
+   EXPECT_EQ(10, r.tv_nsec);
+
+   timespec_add_nsec(&r, &r, (NSEC_PER_SEC * 3ULL) - 9ULL);
+   EXPECT_EQ(8, r.tv_sec);
+   EXPECT_EQ(1, r.tv_nsec);
+
+   timespec_add_nsec(&r, &r, (NSEC_PER_SEC * 7ULL) + (NSEC_PER_SEC - 1ULL));
+   EXPECT_EQ(16, r.tv_sec);
+   EXPECT_EQ(0, r.tv_nsec);
+}
+
+TEST(timespec_test, timespec_add_msec)
+{
+   struct timespec a, r;
+
+   a.tv_sec = 1000;
+   a.tv_nsec = 1;
+   timespec_add_msec(&r, &a, 2002);
+   EXPECT_EQ(1002, r.tv_sec);
+   EXPECT_EQ(2000001, r.tv_nsec);
+}
+
+TEST(timespec_test, timespec_sub_to_nsec)
+{
+   struct timespec a, b;
+
+   a.tv_sec = 1000;
+   a.tv_nsec = 1;
+   b.tv_sec = 1;
+   b.tv_nsec = 2;
+   EXPECT_EQ((999LL * NSEC_PER_SEC) - 1, timespec_sub_to_nsec(&a, &b));
+}
+
+TEST(timespec_test, timespec_sub_to_msec)
+{
+   struct timespec a, b;
+
+   a.tv_sec = 1000;
+   a.tv_nsec = 2000000L;
+   b.tv_sec = 2;
+   b.tv_nsec = 1000000L;
+   EXPECT_EQ((998 * 1000) + 1, timespec_sub_to_msec(&a, &b));
+}
+
+TEST(timespec_test, timespec_from_nsec)
+{
+   struct timespec a;
+
+   timespec_from_nsec(&a, 0);
+   EXPECT_EQ(0, a.tv_sec);
+   EXPECT_EQ(0, a.tv_nsec);
+
+   timespec_from_nsec(&a, NSEC_PER_SEC - 1);
+   EXPECT_EQ(0, a.tv_sec);
+   EXPECT_EQ(NSEC_PER_SEC - 1, a.tv_nsec);
+
+   timespec_from_nsec(&a, NSEC_PER_SEC);
+   EXPECT_EQ(1, a.tv_sec);
+   EXPECT_EQ(0, a.tv_nsec);
+
+   timespec_from_nsec(&a, (5LL * NSEC_PER_SEC) + 1);
+   EXPECT_EQ(5, a.tv_sec);
+   EXPECT_EQ(1, a.tv_nsec);
+}
+
+TEST(timespec_test, timespec_from_usec)
+{
+   struct timespec a;
+
+   timespec_from_usec(&a, 0);
+   EXPECT_EQ(0, a.tv_sec);
+   EXPECT_EQ(0, a.tv_nsec);
+
+   timespec_from_usec(&a, 999999);
+   EXPECT_EQ(0, a.tv_sec);
+   EXPECT_EQ(999999 * 1000, a.tv_nsec);
+
+   timespec_from_usec(&a, 1000000);
+   EXPECT_EQ(1, a.tv_sec);
+   EXPECT_EQ(0, a.tv_nsec);
+
+   timespec_from_usec(&a, 5000001);
+   EXPECT_EQ(5, a.tv_sec);
+   EXPECT_EQ(1000, a.tv_nsec);
+}
+
+TEST(timespec_test, timespec_from_msec)
+{
+   struct timespec a;
+
+   timespec_from_msec(&a, 0);
+   EXPECT_EQ(0, a.tv_sec);
+   EXPECT_EQ(0, a.tv_nsec);
+
+   timespec_from_msec(&a, 999);
+   EXPECT_EQ(0, a.tv_sec);
+   EXPECT_EQ(999 * 1000000, a.tv_nsec);
+
+   timespec_from_msec(&a, 1000);
+   EXPECT_EQ(1, a.tv_sec);
+   EXPECT_EQ(0, a.tv_nsec);
+
+   timespec_from_msec(&a, 5001);
+   EXPECT_EQ(5, a.tv_sec);
+   EXPECT_EQ(1000000, a.tv_nsec);
+}
+
+TEST(timespec_test, timespec_from_proto)
+{
+   struct timespec a;
+
+   timespec_from_proto(&a, 0, 0, 0);
+   EXPECT_EQ(0, a.tv_sec);
+   EXPECT_EQ(0, a.tv_nsec);
+
+   timespec_from_proto(&a, 0, 1234, 9999);
+   EXPECT_EQ(1234, a.tv_sec);
+   EXPECT_EQ(9999, a.tv_nsec);
+
+   timespec_from_proto(&a, 0x1234, 0x5678, 1);
+   EXPECT_EQ((time_t)0x0000123400005678LL, a.tv_sec);
+   EXPECT_EQ(1, a.tv_nsec);
+}
+
+TEST(timespec_test, timespec_is_zero)
+{
+   struct timespec zero = { 0 };
+   struct timespec non_zero_sec = { .tv_sec = 1, .tv_nsec = 0 };
+   struct timespec non_zero_nsec = { .tv_sec = 0, .tv_nsec = 1 };
+
+   EXPECT_TRUE(timespec_is_zero(&zero));
+   EXPECT_FALSE(timespec_is_zero(&non_zero_nsec));
+   EXPECT_FALSE(timespec_is_zero(&non_zero_sec));
+}
+
+TEST(timespec_test, timespec_eq)
+{
+   struct timespec a = { .tv_sec = 2, .tv_nsec = 1 };
+   struct timespec b = { .tv_sec = -1, .tv_nsec = 2 };
+
+   EXPECT_TRUE(timespec_eq(&a, &a));
+   EXPECT_TRUE(timespec_eq(&b, &b));
+
+   EXPECT_FALSE(timespec_eq(&a, &b));
+   EXPECT_FALSE(timespec_eq(&b, &a));
+}
diff --git a/src/util/timespec.h b/src/util/timespec.h
new file mode 100644
index 00000000000..ab112e4e621
--- /dev/null
+++ b/src/util/timespec.h
@@ -0,0 +1,330 @@
+/*
+ * Copyright © 2014 - 2015 Collabora, Ltd.
+ *
+ * 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 (including the
+ * next paragraph) 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.
+ */
+
+/**
+ * \file timespec.h
+ *
+ * Helpers to deal with timespec structures.
+ */
+
+#ifndef TIMESPEC_H
+#define TIMESPEC_H
+
+#include <stdint.h>
+#include <assert.h>
+#include <time.h>
+#include <stdbool.h>
+
+#define NSEC_PER_SEC 1000000000
+
+/**
+ * Add timespecs
+ *
+ * \param r[out] result: a + b
+ * \param a[in] operand
+ * \param b[in] operand
+ */
+static inline void
+timespec_add(struct timespec *r,
+             const struct timespec *a, const struct timespec *b)
+{
+   r->tv_sec = a->tv_sec + b->tv_sec;
+   r->tv_nsec = a->tv_nsec + b->tv_nsec;
+   if (r->tv_nsec > NSEC_PER_SEC) {
+      r->tv_sec++;
+      r->tv_nsec -= NSEC_PER_SEC;
+   }
+}
+
+/**
+ * Subtract timespecs
+ *
+ * \param r[out] result: a - b
+ * \param a[in] operand
+ * \param b[in] operand
+ */
+static inline void
+timespec_sub(struct timespec *r,
+             const struct timespec *a, const struct timespec *b)
+{
+   r->tv_sec = a->tv_sec - b->tv_sec;
+   r->tv_nsec = a->tv_nsec - b->tv_nsec;
+   if (r->tv_nsec < 0) {
+      r->tv_sec--;
+      r->tv_nsec += NSEC_PER_SEC;
+   }
+}
+
+/**
+ * Add a nanosecond value to a timespec
+ *
+ * \param r[out] result: a + b
+ * \param a[in] base operand as timespec
+ * \param b[in] operand in nanoseconds
+ */
+static inline void
+timespec_add_nsec(struct timespec *r, const struct timespec *a, int64_t b)
+{
+   r->tv_sec = a->tv_sec + (b / NSEC_PER_SEC);
+   r->tv_nsec = a->tv_nsec + (b % NSEC_PER_SEC);
+
+   if (r->tv_nsec >= NSEC_PER_SEC) {
+      r->tv_sec++;
+      r->tv_nsec -= NSEC_PER_SEC;
+   } else if (r->tv_nsec < 0) {
+      r->tv_sec--;
+      r->tv_nsec += NSEC_PER_SEC;
+   }
+}
+
+/**
+ * Add a millisecond value to a timespec
+ *
+ * \param r[out] result: a + b
+ * \param a[in] base operand as timespec
+ * \param b[in] operand in milliseconds
+ */
+static inline void
+timespec_add_msec(struct timespec *r, const struct timespec *a, int64_t b)
+{
+   timespec_add_nsec(r, a, b * 1000000);
+}
+
+/**
+ * Convert timespec to nanoseconds
+ *
+ * \param a timespec
+ * \return nanoseconds
+ */
+static inline int64_t
+timespec_to_nsec(const struct timespec *a)
+{
+   return (int64_t)a->tv_sec * NSEC_PER_SEC + a->tv_nsec;
+}
+
+/**
+ * Subtract timespecs and return result in nanoseconds
+ *
+ * \param a[in] operand
+ * \param b[in] operand
+ * \return to_nanoseconds(a - b)
+ */
+static inline int64_t
+timespec_sub_to_nsec(const struct timespec *a, const struct timespec *b)
+{
+   struct timespec r;
+   timespec_sub(&r, a, b);
+   return timespec_to_nsec(&r);
+}
+
+/**
+ * Convert timespec to milliseconds
+ *
+ * \param a timespec
+ * \return milliseconds
+ *
+ * Rounding to integer milliseconds happens always down (floor()).
+ */
+static inline int64_t
+timespec_to_msec(const struct timespec *a)
+{
+   return (int64_t)a->tv_sec * 1000 + a->tv_nsec / 1000000;
+}
+
+/**
+ * Subtract timespecs and return result in milliseconds
+ *
+ * \param a[in] operand
+ * \param b[in] operand
+ * \return to_milliseconds(a - b)
+ */
+static inline int64_t
+timespec_sub_to_msec(const struct timespec *a, const struct timespec *b)
+{
+   return timespec_sub_to_nsec(a, b) / 1000000;
+}
+
+/**
+ * Convert timespec to microseconds
+ *
+ * \param a timespec
+ * \return microseconds
+ *
+ * Rounding to integer microseconds happens always down (floor()).
+ */
+static inline int64_t
+timespec_to_usec(const struct timespec *a)
+{
+   return (int64_t)a->tv_sec * 1000000 + a->tv_nsec / 1000;
+}
+
+/**
+ * Convert timespec to protocol data
+ *
+ * \param a timespec
+ * \param tv_sec_hi[out] the high bytes of the seconds part
+ * \param tv_sec_lo[out] the low bytes of the seconds part
+ * \param tv_nsec[out] the nanoseconds part
+ *
+ * The input timespec must be normalized (the nanoseconds part should
+ * be less than 1 second) and non-negative.
+ */
+static inline void
+timespec_to_proto(const struct timespec *a, uint32_t *tv_sec_hi,
+                  uint32_t *tv_sec_lo, uint32_t *tv_nsec)
+{
+   assert(a->tv_sec >= 0);
+   assert(a->tv_nsec >= 0 && a->tv_nsec < NSEC_PER_SEC);
+
+   uint64_t sec64 = a->tv_sec;
+
+   *tv_sec_hi = sec64 >> 32;
+   *tv_sec_lo = sec64 & 0xffffffff;
+   *tv_nsec = a->tv_nsec;
+}
+
+/**
+ * Convert nanoseconds to timespec
+ *
+ * \param a timespec
+ * \param b nanoseconds
+ */
+static inline void
+timespec_from_nsec(struct timespec *a, int64_t b)
+{
+   a->tv_sec = b / NSEC_PER_SEC;
+   a->tv_nsec = b % NSEC_PER_SEC;
+}
+
+/**
+ * Convert microseconds to timespec
+ *
+ * \param a timespec
+ * \param b microseconds
+ */
+static inline void
+timespec_from_usec(struct timespec *a, int64_t b)
+{
+   timespec_from_nsec(a, b * 1000);
+}
+
+/**
+ * Convert milliseconds to timespec
+ *
+ * \param a timespec
+ * \param b milliseconds
+ */
+static inline void
+timespec_from_msec(struct timespec *a, int64_t b)
+{
+   timespec_from_nsec(a, b * 1000000);
+}
+
+/**
+ * Convert protocol data to timespec
+ *
+ * \param a[out] timespec
+ * \param tv_sec_hi the high bytes of seconds part
+ * \param tv_sec_lo the low bytes of seconds part
+ * \param tv_nsec the nanoseconds part
+ */
+static inline void
+timespec_from_proto(struct timespec *a, uint32_t tv_sec_hi,
+                    uint32_t tv_sec_lo, uint32_t tv_nsec)
+{
+   a->tv_sec = ((uint64_t)tv_sec_hi << 32) + tv_sec_lo;
+   a->tv_nsec = tv_nsec;
+}
+
+/**
+ * Check if a timespec is zero
+ *
+ * \param a timespec
+ * \return whether the timespec is zero
+ */
+static inline bool
+timespec_is_zero(const struct timespec *a)
+{
+   return a->tv_sec == 0 && a->tv_nsec == 0;
+}
+
+/**
+ * Check if two timespecs are equal
+ *
+ * \param a[in] timespec to check
+ * \param b[in] timespec to check
+ * \return whether timespecs a and b are equal
+ */
+static inline bool
+timespec_eq(const struct timespec *a, const struct timespec *b)
+{
+   return a->tv_sec == b->tv_sec &&
+      a->tv_nsec == b->tv_nsec;
+}
+
+/**
+ * Convert milli-Hertz to nanoseconds
+ *
+ * \param mhz frequency in mHz, not zero
+ * \return period in nanoseconds
+ */
+static inline int64_t
+millihz_to_nsec(uint32_t mhz)
+{
+   assert(mhz > 0);
+   return 1000000000000LL / mhz;
+}
+
+/**
+ * Checks whether a timespec value is after another
+ *
+ * \param a[in] timespec to compare
+ * \param b[in] timespec to compare
+ * \return whether a is after b
+ */
+static inline bool
+timespec_after(const struct timespec *a, const struct timespec *b)
+{
+   return (a->tv_sec == b->tv_sec) ?
+      (a->tv_nsec > b->tv_nsec) :
+      (a->tv_sec > b->tv_sec);
+}
+
+/**
+ * Checks whether a timespec value is after the current time
+ *
+ * \param clock_domain[in] clock in which to do the comparison
+ * \param deadline[in] timespec to compare
+ * \return whether deadline is after the current time
+ */
+static inline bool
+timespec_passed(clockid_t clock_domain, const struct timespec *deadline)
+{
+   struct timespec current_time;
+   clock_gettime(clock_domain, &current_time);
+   return timespec_after(&current_time, deadline);
+}
+
+#endif /* TIMESPEC_H */