luatz/gettime.lua

   1 local _M = { }
   2
   3 _M.source , _M.resolution , _M.gettime = (function()
   4         local has_syscall , syscall = pcall ( require , "syscall" )
   5         if has_syscall then
   6                 if syscall.clock_gettime then
   7                         local clock_id = syscall.c.CLOCK.REALTIME
   8                         local function timespec_to_number ( timespec )
   9                                 return tonumber ( timespec.tv_sec ) + tonumber ( timespec.tv_nsec ) * 1e-9
  10                         end
  11                         return "syscall.clock_gettime(CLOCK_REALTIME)" ,
  12                                 syscall.clock_getres and timespec_to_number ( syscall.clock_getres ( clock_id ) ) or 1e-9 ,
  13                                 function ( )
  14                                         return timespec_to_number ( syscall.clock_gettime ( clock_id ) )
  15                                 end
  16
  17                 elseif syscall.gettimeofday then
  18                         local function timeval_to_number ( timeval )
  19                                 return tonumber ( timeval.tv_sec ) + tonumber ( timeval.tv_nsec ) * 1e-6
  20                         end
  21                         return "syscall.gettimeofday()" , 1e-6 ,
  22                                 function ( )
  23                                         return timeval_to_number ( syscall.gettimeofday ( ) )
  24                                 end
  25                 end
  26         end
  27
  28         local has_socket , socket = pcall ( require , "socket" )
  29         if has_socket and socket.gettime then
  30                 -- on windows, this uses GetSystemTimeAsFileTime, which has resolution of 1e-7
  31                 -- on linux, this uses gettimeofday, which has resolution of 1e-6
  32                 return "socket.gettime()" , 1e-6 , socket.gettime
  33         end
  34
  35         return "os.time()" , 1 , os.time
  36 end)()
  37
  38 return _M