1 files changed, 217 insertions, 0 deletions
diff --git a/src/basic/time-util.h b/src/basic/time-util.h
new file mode 100644
index 0000000..c98f95a
--- /dev/null
+++ b/src/basic/time-util.h
@@ -0,0 +1,217 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <inttypes.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <time.h>
+
+typedef uint64_t usec_t;
+typedef uint64_t nsec_t;
+
+#define PRI_NSEC PRIu64
+#define PRI_USEC PRIu64
+#define NSEC_FMT "%" PRI_NSEC
+#define USEC_FMT "%" PRI_USEC
+
+#include "macro.h"
+
+typedef struct dual_timestamp {
+        usec_t realtime;
+        usec_t monotonic;
+} dual_timestamp;
+
+typedef struct triple_timestamp {
+        usec_t realtime;
+        usec_t monotonic;
+        usec_t boottime;
+} triple_timestamp;
+
+typedef enum TimestampStyle {
+        TIMESTAMP_PRETTY,
+        TIMESTAMP_US,
+        TIMESTAMP_UTC,
+        TIMESTAMP_US_UTC,
+        TIMESTAMP_UNIX,
+        _TIMESTAMP_STYLE_MAX,
+        _TIMESTAMP_STYLE_INVALID = -EINVAL,
+} TimestampStyle;
+
+#define USEC_INFINITY ((usec_t) UINT64_MAX)
+#define NSEC_INFINITY ((nsec_t) UINT64_MAX)
+
+#define MSEC_PER_SEC  1000ULL
+#define USEC_PER_SEC  ((usec_t) 1000000ULL)
+#define USEC_PER_MSEC ((usec_t) 1000ULL)
+#define NSEC_PER_SEC  ((nsec_t) 1000000000ULL)
+#define NSEC_PER_MSEC ((nsec_t) 1000000ULL)
+#define NSEC_PER_USEC ((nsec_t) 1000ULL)
+
+#define USEC_PER_MINUTE ((usec_t) (60ULL*USEC_PER_SEC))
+#define NSEC_PER_MINUTE ((nsec_t) (60ULL*NSEC_PER_SEC))
+#define USEC_PER_HOUR ((usec_t) (60ULL*USEC_PER_MINUTE))
+#define NSEC_PER_HOUR ((nsec_t) (60ULL*NSEC_PER_MINUTE))
+#define USEC_PER_DAY ((usec_t) (24ULL*USEC_PER_HOUR))
+#define NSEC_PER_DAY ((nsec_t) (24ULL*NSEC_PER_HOUR))
+#define USEC_PER_WEEK ((usec_t) (7ULL*USEC_PER_DAY))
+#define NSEC_PER_WEEK ((nsec_t) (7ULL*NSEC_PER_DAY))
+#define USEC_PER_MONTH ((usec_t) (2629800ULL*USEC_PER_SEC))
+#define NSEC_PER_MONTH ((nsec_t) (2629800ULL*NSEC_PER_SEC))
+#define USEC_PER_YEAR ((usec_t) (31557600ULL*USEC_PER_SEC))
+#define NSEC_PER_YEAR ((nsec_t) (31557600ULL*NSEC_PER_SEC))
+
+/* We assume a maximum timezone length of 6. TZNAME_MAX is not defined on Linux, but glibc internally initializes this
+ * to 6. Let's rely on that. */
+#define FORMAT_TIMESTAMP_MAX (3U+1U+10U+1U+8U+1U+6U+1U+6U+1U)
+#define FORMAT_TIMESTAMP_WIDTH 28U /* when outputting, assume this width */
+#define FORMAT_TIMESTAMP_RELATIVE_MAX 256U
+#define FORMAT_TIMESPAN_MAX 64U
+
+#define TIME_T_MAX (time_t)((UINTMAX_C(1) << ((sizeof(time_t) << 3) - 1)) - 1)
+
+#define DUAL_TIMESTAMP_NULL ((struct dual_timestamp) {})
+#define TRIPLE_TIMESTAMP_NULL ((struct triple_timestamp) {})
+
+usec_t now(clockid_t clock);
+nsec_t now_nsec(clockid_t clock);
+
+usec_t map_clock_usec(usec_t from, clockid_t from_clock, clockid_t to_clock);
+
+dual_timestamp* dual_timestamp_get(dual_timestamp *ts);
+dual_timestamp* dual_timestamp_from_realtime(dual_timestamp *ts, usec_t u);
+dual_timestamp* dual_timestamp_from_monotonic(dual_timestamp *ts, usec_t u);
+dual_timestamp* dual_timestamp_from_boottime(dual_timestamp *ts, usec_t u);
+
+triple_timestamp* triple_timestamp_get(triple_timestamp *ts);
+triple_timestamp* triple_timestamp_from_realtime(triple_timestamp *ts, usec_t u);
+
+#define DUAL_TIMESTAMP_HAS_CLOCK(clock)                               \
+        IN_SET(clock, CLOCK_REALTIME, CLOCK_REALTIME_ALARM, CLOCK_MONOTONIC)
+
+#define TRIPLE_TIMESTAMP_HAS_CLOCK(clock)                               \
+        IN_SET(clock, CLOCK_REALTIME, CLOCK_REALTIME_ALARM, CLOCK_MONOTONIC, CLOCK_BOOTTIME, CLOCK_BOOTTIME_ALARM)
+
+static inline bool timestamp_is_set(usec_t timestamp) {
+        return timestamp > 0 && timestamp != USEC_INFINITY;
+}
+
+static inline bool dual_timestamp_is_set(const dual_timestamp *ts) {
+        return timestamp_is_set(ts->realtime) ||
+               timestamp_is_set(ts->monotonic);
+}
+
+static inline bool triple_timestamp_is_set(const triple_timestamp *ts) {
+        return timestamp_is_set(ts->realtime) ||
+               timestamp_is_set(ts->monotonic) ||
+               timestamp_is_set(ts->boottime);
+}
+
+usec_t triple_timestamp_by_clock(triple_timestamp *ts, clockid_t clock);
+
+usec_t timespec_load(const struct timespec *ts) _pure_;
+nsec_t timespec_load_nsec(const struct timespec *ts) _pure_;
+struct timespec* timespec_store(struct timespec *ts, usec_t u);
+struct timespec* timespec_store_nsec(struct timespec *ts, nsec_t n);
+
+#define TIMESPEC_STORE(u) timespec_store(&(struct timespec) {}, (u))
+
+usec_t timeval_load(const struct timeval *tv) _pure_;
+struct timeval* timeval_store(struct timeval *tv, usec_t u);
+
+#define TIMEVAL_STORE(u) timeval_store(&(struct timeval) {}, (u))
+
+char* format_timestamp_style(char *buf, size_t l, usec_t t, TimestampStyle style) _warn_unused_result_;
+char* format_timestamp_relative(char *buf, size_t l, usec_t t) _warn_unused_result_;
+char* format_timespan(char *buf, size_t l, usec_t t, usec_t accuracy) _warn_unused_result_;
+
+_warn_unused_result_
+static inline char* format_timestamp(char *buf, size_t l, usec_t t) {
+        return format_timestamp_style(buf, l, t, TIMESTAMP_PRETTY);
+}
+
+/* Note: the lifetime of the compound literal is the immediately surrounding block,
+ * see C11 §6.5.2.5, and
+ * https://stackoverflow.com/questions/34880638/compound-literal-lifetime-and-if-blocks */
+#define FORMAT_TIMESTAMP(t) format_timestamp((char[FORMAT_TIMESTAMP_MAX]){}, FORMAT_TIMESTAMP_MAX, t)
+#define FORMAT_TIMESTAMP_RELATIVE(t)                                    \
+        format_timestamp_relative((char[FORMAT_TIMESTAMP_RELATIVE_MAX]){}, FORMAT_TIMESTAMP_RELATIVE_MAX, t)
+#define FORMAT_TIMESPAN(t, accuracy) format_timespan((char[FORMAT_TIMESPAN_MAX]){}, FORMAT_TIMESPAN_MAX, t, accuracy)
+#define FORMAT_TIMESTAMP_STYLE(t, style) \
+        format_timestamp_style((char[FORMAT_TIMESTAMP_MAX]){}, FORMAT_TIMESTAMP_MAX, t, style)
+
+int parse_timestamp(const char *t, usec_t *usec);
+
+int parse_sec(const char *t, usec_t *usec);
+int parse_sec_fix_0(const char *t, usec_t *usec);
+int parse_sec_def_infinity(const char *t, usec_t *usec);
+int parse_time(const char *t, usec_t *usec, usec_t default_unit);
+int parse_nsec(const char *t, nsec_t *nsec);
+
+int get_timezones(char ***l);
+int verify_timezone(const char *name, int log_level);
+static inline bool timezone_is_valid(const char *name, int log_level) {
+        return verify_timezone(name, log_level) >= 0;
+}
+
+bool clock_supported(clockid_t clock);
+
+usec_t usec_shift_clock(usec_t, clockid_t from, clockid_t to);
+
+int get_timezone(char **timezone);
+
+time_t mktime_or_timegm(struct tm *tm, bool utc);
+struct tm *localtime_or_gmtime_r(const time_t *t, struct tm *tm, bool utc);
+
+uint32_t usec_to_jiffies(usec_t usec);
+usec_t jiffies_to_usec(uint32_t jiffies);
+
+bool in_utc_timezone(void);
+
+static inline usec_t usec_add(usec_t a, usec_t b) {
+        /* Adds two time values, and makes sure USEC_INFINITY as input results as USEC_INFINITY in output,
+         * and doesn't overflow. */
+
+        if (a > USEC_INFINITY - b) /* overflow check */
+                return USEC_INFINITY;
+
+        return a + b;
+}
+
+static inline usec_t usec_sub_unsigned(usec_t timestamp, usec_t delta) {
+        if (timestamp == USEC_INFINITY) /* Make sure infinity doesn't degrade */
+                return USEC_INFINITY;
+        if (timestamp < delta)
+                return 0;
+
+        return timestamp - delta;
+}
+
+static inline usec_t usec_sub_signed(usec_t timestamp, int64_t delta) {
+        if (delta == INT64_MIN) { /* prevent overflow */
+                assert_cc(-(INT64_MIN + 1) == INT64_MAX);
+                assert_cc(USEC_INFINITY > INT64_MAX);
+                return usec_add(timestamp, (usec_t) INT64_MAX + 1);
+        }
+        if (delta < 0)
+                return usec_add(timestamp, (usec_t) (-delta));
+
+        return usec_sub_unsigned(timestamp, (usec_t) delta);
+}
+
+#if SIZEOF_TIME_T == 8
+  /* The last second we can format is 31. Dec 9999, 1s before midnight, because otherwise we'd enter 5 digit
+   * year territory. However, since we want to stay away from this in all timezones we take one day off. */
+#  define USEC_TIMESTAMP_FORMATTABLE_MAX ((usec_t) 253402214399000000)
+#elif SIZEOF_TIME_T == 4
+/* With a 32bit time_t we can't go beyond 2038... */
+#  define USEC_TIMESTAMP_FORMATTABLE_MAX ((usec_t) 2147483647000000)
+#else
+#  error "Yuck, time_t is neither 4 nor 8 bytes wide?"
+#endif
+
+int time_change_fd(void);
+
+const char* timestamp_style_to_string(TimestampStyle t) _const_;
+TimestampStyle timestamp_style_from_string(const char *s) _pure_;