1 files changed, 63 insertions, 0 deletions
diff --git a/libc-bottom-half/cloudlibc/src/common/time.h b/libc-bottom-half/cloudlibc/src/common/time.h
new file mode 100644
index 0000000..08e2852
--- /dev/null
+++ b/libc-bottom-half/cloudlibc/src/common/time.h
@@ -0,0 +1,63 @@
+// Copyright (c) 2015-2016 Nuxi, https://nuxi.nl/
+//
+// SPDX-License-Identifier: BSD-2-Clause
+
+#ifndef COMMON_TIME_H
+#define COMMON_TIME_H
+
+#include <common/limits.h>
+
+#include <sys/time.h>
+
+#include <wasi/api.h>
+#include <stdbool.h>
+#include <time.h>
+
+#define NSEC_PER_SEC 1000000000
+
+static inline bool timespec_to_timestamp_exact(
+    const struct timespec *timespec, __wasi_timestamp_t *timestamp) {
+  // Invalid nanoseconds field.
+  if (timespec->tv_nsec < 0 || timespec->tv_nsec >= NSEC_PER_SEC)
+    return false;
+
+  // Timestamps before the Epoch are not supported.
+  if (timespec->tv_sec < 0)
+    return false;
+
+  // Make sure our timestamp does not overflow.
+  return !__builtin_mul_overflow(timespec->tv_sec, NSEC_PER_SEC, timestamp) &&
+         !__builtin_add_overflow(*timestamp, timespec->tv_nsec, timestamp);
+}
+
+static inline bool timespec_to_timestamp_clamp(
+    const struct timespec *timespec, __wasi_timestamp_t *timestamp) {
+  // Invalid nanoseconds field.
+  if (timespec->tv_nsec < 0 || timespec->tv_nsec >= NSEC_PER_SEC)
+    return false;
+
+  if (timespec->tv_sec < 0) {
+    // Timestamps before the Epoch are not supported.
+    *timestamp = 0;
+  } else if (__builtin_mul_overflow(timespec->tv_sec, NSEC_PER_SEC, timestamp) ||
+             __builtin_add_overflow(*timestamp, timespec->tv_nsec, timestamp)) {
+    // Make sure our timestamp does not overflow.
+    *timestamp = NUMERIC_MAX(__wasi_timestamp_t);
+  }
+  return true;
+}
+
+static inline struct timespec timestamp_to_timespec(
+    __wasi_timestamp_t timestamp) {
+  // Decompose timestamp into seconds and nanoseconds.
+  return (struct timespec){.tv_sec = timestamp / NSEC_PER_SEC,
+                           .tv_nsec = timestamp % NSEC_PER_SEC};
+}
+
+static inline struct timeval timestamp_to_timeval(
+    __wasi_timestamp_t timestamp) {
+  struct timespec ts = timestamp_to_timespec(timestamp);
+  return (struct timeval){.tv_sec = ts.tv_sec, ts.tv_nsec / 1000};
+}
+
+#endif