Add Crystal::System::Time.ticks

src/crystal/system/time.cr

@@ -3,8 +3,14 @@ module Crystal::System::Time
   # since `0001-01-01 00:00:00`.
   # def self.compute_utc_seconds_and_nanoseconds : {Int64, Int32}
 
+  # Returns the current time from the monotonic clock in `{seconds,
+  # nanoseconds}`.
   # def self.monotonic : {Int64, Int32}
 
+  # Returns the current time from the monotonic clock in nanoseconds.
+  # Doesn't raise nor allocates GC HEAP memory.
+  # def self.ticks : UInt64
+
   # Returns a list of paths where time zone data should be looked up.
   # def self.zone_sources : Enumerable(String)
 

src/crystal/system/unix/time.cr

@@ -16,26 +16,27 @@ require "c/time"
 {% end %}
 
 module Crystal::System::Time
-  UnixEpochInSeconds = 62135596800_i64
+  UNIX_EPOCH_IN_SECONDS  = 62135596800_i64
+  NANOSECONDS_PER_SECOND =   1_000_000_000
 
   def self.compute_utc_seconds_and_nanoseconds : {Int64, Int32}
     {% if LibC.has_method?("clock_gettime") %}
       ret = LibC.clock_gettime(LibC::CLOCK_REALTIME, out timespec)
       raise RuntimeError.from_errno("clock_gettime") unless ret == 0
-      {timespec.tv_sec.to_i64 + UnixEpochInSeconds, timespec.tv_nsec.to_i}
+      {timespec.tv_sec.to_i64 + UNIX_EPOCH_IN_SECONDS, timespec.tv_nsec.to_i}
     {% else %}
       ret = LibC.gettimeofday(out timeval, nil)
       raise RuntimeError.from_errno("gettimeofday") unless ret == 0
-      {timeval.tv_sec.to_i64 + UnixEpochInSeconds, timeval.tv_usec.to_i * 1_000}
+      {timeval.tv_sec.to_i64 + UNIX_EPOCH_IN_SECONDS, timeval.tv_usec.to_i * 1_000}
     {% end %}
   end
 
   def self.monotonic : {Int64, Int32}
     {% if flag?(:darwin) %}
       info = mach_timebase_info
       total_nanoseconds = LibC.mach_absolute_time * info.numer // info.denom
-      seconds = total_nanoseconds // 1_000_000_000
-      nanoseconds = total_nanoseconds.remainder(1_000_000_000)
+      seconds = total_nanoseconds // NANOSECONDS_PER_SECOND
+      nanoseconds = total_nanoseconds.remainder(NANOSECONDS_PER_SECOND)
       {seconds.to_i64, nanoseconds.to_i32}
     {% else %}
       if LibC.clock_gettime(LibC::CLOCK_MONOTONIC, out tp) == 1
@@ -45,6 +46,16 @@ module Crystal::System::Time
     {% end %}
   end
 
+  def self.ticks : UInt64
+    {% if flag?(:darwin) %}
+      info = mach_timebase_info
+      LibC.mach_absolute_time &* info.numer // info.denom
+    {% else %}
+      LibC.clock_gettime(LibC::CLOCK_MONOTONIC, out tp)
+      tp.tv_sec.to_u64! &* NANOSECONDS_PER_SECOND &+ tp.tv_nsec.to_u64!
+    {% end %}
+  end
+
   def self.to_timespec(time : ::Time)
     t = uninitialized LibC::Timespec
     t.tv_sec = typeof(t.tv_sec).new(time.to_unix)

src/crystal/system/win32/time.cr

@@ -53,21 +53,24 @@ module Crystal::System::Time
     ((filetime.dwHighDateTime.to_u64 << 32) | filetime.dwLowDateTime.to_u64).to_f64 / FILETIME_TICKS_PER_SECOND.to_f64
   end
 
-  @@performance_frequency : Int64 = begin
-    ret = LibC.QueryPerformanceFrequency(out frequency)
-    if ret == 0
-      raise RuntimeError.from_winerror("QueryPerformanceFrequency")
-    end
+  @@performance_frequency : Int64?
 
-    frequency
+  private def self.performance_frequency
+    @@performance_frequency ||= begin
+      LibC.QueryPerformanceFrequency(out frequency)
+      frequency
+    end
   end
 
   def self.monotonic : {Int64, Int32}
-    if LibC.QueryPerformanceCounter(out ticks) == 0
-      raise RuntimeError.from_winerror("QueryPerformanceCounter")
-    end
+    LibC.QueryPerformanceCounter(out ticks)
+    frequency = performance_frequency
+    {ticks // frequency, (ticks.remainder(frequency) * NANOSECONDS_PER_SECOND / frequency).to_i32}
+  end
 
-    {ticks // @@performance_frequency, (ticks.remainder(@@performance_frequency) * NANOSECONDS_PER_SECOND / @@performance_frequency).to_i32}
+  def self.ticks : UInt64
+    LibC.QueryPerformanceCounter(out ticks)
+    ticks.to_u64! &* (NANOSECONDS_PER_SECOND // performance_frequency)
   end
 
   def self.load_localtime : ::Time::Location?