jl_stat_ctime

[Brandon Taylor]

Right now in base jl_stat_ctime looks like this:

JL_DLLEXPORT double jl_stat_ctime(char *statbuf)

{

    uv_stat_t *s;

    s = (uv_stat_t*)statbuf;

    return (double)s->st_ctim.tv_sec + (double)s->st_ctim.tv_nsec * 1e-9;

}

And it's called with

ccall(:jl_stat_ctime,   Float64, (Ptr{UInt8},), buf)

I'd like to simplify this.

I'd like a type

type FineComputerTime

    seconds::Int

    nanoseconds::Int

end

And a way to fill it in using the stat buffer.

Can anyone offer some tips? The c code keeps confusing me.

I

[Jeffrey Sarnoff]

Look at the help for tic() and toc().

Do you care about interfacing directly with jl_ routines?  If not, and you are trying to make your own harness ... perhaps this would help:

#=

   Using immutable rather than type with fields that are 

   simple and immediate values keeps information directly

   available (rather than indirectly available, like arrays).

   Use Int64 because nanosecond timing uses 64 bits (UInt64).

   time_ns() "Get the time in nanoseconds. 

              The time corresponding to 0 is undefined,

              and wraps every 5.8 years."

   time_zero because the timer is given as a UInt64 value, and 

            there are more of those than positive Int64s.

=#

const time_zero = [time_ns()]

get_time_zero() = time_zero[1]

function set_time_zero(nanoseconds::UInt64)

    time_zero[1] = nanoseconds

    return nanoseconds

end    

immutable FineComputerTime

    seconds::Int64

    nanoseconds::Int64

end

function FineComputerTime(nanosecs::UInt64)

    nanosecs -= get_time_zero()

    secs, nsecs = fldmod( nanosecs, 1_000_000_000%UInt64 ) # value%UInt64 is a fast way to force the type

    return FineComputerTime( Int64(secs), Int64(nsecs) )

end

FineComputerTime() = FineComputerTime(time_ns())

On Friday, October 28, 2016 at 10:07:42 AM UTC-4, Brandon Taylor wrote:

Right now in base jl_stat_ctime looks like this:

JL_DLLEXPORT double jl_stat_ctime(char *statbuf)

{

    uv_stat_t *s;

    s = (uv_stat_t*)statbuf;

    return (double)s->st_ctim.tv_sec + (double)s->st_ctim.tv_nsec * 1e-9;

}

And it's called with

ccall(:jl_stat_ctime,   Float64, (Ptr{UInt8},), buf)

I'd like to simplify this.

I'd like a type

type FineComputerTime

    seconds::Int

    nanoseconds::Int

end

And a way to fill it in using the stat buffer.

Can anyone offer some tips? The c code keeps confusing me.

I

[Jeffrey Sarnoff]

If you are working with file information, use e.g. `file_stats=stat(); file_creation_time = file_stats.ctime; file_modification_time = file_stat.mtime;` 

You will get Float64 values, to make FineComputerTimes from those, 

function FineComputerTime(stat_time::Float64)
   nanosecs = round(UInt64, stat_time * 1.0e9)
   return FineComputerTime(nanosecs)
end

On Tuesday, November 1, 2016 at 3:44:07 PM UTC-4, Jeffrey Sarnoff wrote:

Look at the help for tic() and toc().

Do you care about interfacing directly with jl_ routines?  If not, and you are trying to make your own harness ... perhaps this would help:

#=

   Using immutable rather than type with fields that are 

   simple and immediate values keeps information directly

   available (rather than indirectly available, like arrays).

   Use Int64 because nanosecond timing uses 64 bits (UInt64).

   time_ns() "Get the time in nanoseconds. 

              The time corresponding to 0 is undefined,

              and wraps every 5.8 years."

   time_zero because the timer is given as a UInt64 value, and 

            there are more of those than positive Int64s.

=#

const time_zero = [time_ns()]

get_time_zero() = time_zero[1]

function set_time_zero(nanoseconds::UInt64)

    time_zero[1] = nanoseconds

    return nanoseconds

end    

immutable FineComputerTime

    seconds::Int64

    nanoseconds::Int64

end

function FineComputerTime(nanosecs::UInt64)

    nanosecs -= get_time_zero()

    secs, nsecs = fldmod( nanosecs, 1_000_000_000%UInt64 ) # value%UInt64 is a fast way to force the type

    return FineComputerTime( Int64(secs), Int64(nsecs) )

end

FineComputerTime() = FineComputerTime(time_ns())

On Friday, October 28, 2016 at 10:07:42 AM UTC-4, Brandon Taylor wrote:

Right now in base jl_stat_ctime looks like this:

JL_DLLEXPORT double jl_stat_ctime(char *statbuf)

{

    uv_stat_t *s;

    s = (uv_stat_t*)statbuf;

    return (double)s->st_ctim.tv_sec + (double)s->st_ctim.tv_nsec * 1e-9;

}

And it's called with

ccall(:jl_stat_ctime,   Float64, (Ptr{UInt8},), buf)

I'd like to simplify this.

I'd like a type

type FineComputerTime

    seconds::Int

    nanoseconds::Int

end

And a way to fill it in using the stat buffer.

Can anyone offer some tips? The c code keeps confusing me.

I