## benchmark
require 'benchmark'

total = (ENV['TOTAL'] || 1_000).to_i

strings = Dir["spec/**/*_spec.rb"]

Benchmark.bmbm do |x|
  x.report("loop") do
    times = 0
    while times < total
      strings.each { |s| s }
      times += 1
    end
  end

  x.report("Stat.stat") do
    Stat = File::Stat
    times = 0
    while times < total
      strings.each { |s| Stat.stat s, true }
      times += 1
    end
  end
  
  x.report("File.stat") do
    times = 0
    while times < total
      strings.each { |s| File.stat s }
      times += 1
    end
  end
  
  x.report("File.exist?") do
    times = 0
    while times < total
      strings.each { |s| File.exist? s }
      times += 1
    end
  end
  
  x.report("File.file?") do
    times = 0
    while times < total
      strings.each { |s| File.file? s }
      times += 1
    end
  end
    
  x.report("C stat (1_645_000)") do
    `./stat`
  end
end

## stat.c

#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>

int main(int argc, char *argv[]) {
  struct stat *st, sb;
  int i, total = 1000*1645;
  
  if(argc > 1) {
    st = malloc(sizeof(struct stat));
  } else {
    st = &sb;
  }
  
  for(i = 0; i < total; i++) {
    stat("./spec/ruby/1.8/core/true/and_spec.rb", st);
  }
  
  return 0;
}

gcc -o stat stat.c

## ruby

euler:rubinius brian$ TOTAL=1_000 ruby stat.rb 
Rehearsal ------------------------------------------------------
loop                 0.340000   0.000000   0.340000 (  0.379366)
File.stat            5.350000   7.160000  12.510000 ( 12.629583)
File.exist?          4.280000   6.770000  11.050000 ( 11.173089)
File.file?           4.260000   6.650000  10.910000 ( 10.946640)
C stat (1_645_000)   0.000000   0.000000   6.360000 (  6.378908)
-------------------------------------------- total: 41.170000sec

                         user     system      total        real
loop                 0.350000   0.010000   0.360000 (  0.351319)
File.stat            5.360000   7.120000  12.480000 ( 12.610997)
File.exist?          4.320000   6.590000  10.910000 ( 10.950847)
File.file?           4.280000   6.610000  10.890000 ( 11.923850)
C stat (1_645_000)   0.000000   0.000000   6.380000 (  6.659911)

## rbx with new stat_file primitive

euler:rubinius brian$ rm stat.rbc; TOTAL=1_000 shotgun/rubinius stat.rb 
Rehearsal ------------------------------------------------------
loop                 0.536307   0.000000   0.536307 (  0.536293)
Stat.stat           12.438195   0.000000  12.438195 ( 12.438186)
File.stat           19.902529   0.000000  19.902529 ( 19.902510)
File.exist?         20.560152   0.000000  20.560152 ( 20.560134)
File.file?          38.015128   0.000000  38.015128 ( 38.015113)
C stat (1_645_000)   6.382751   0.000000   6.382751 (  6.382689)
-------------------------------------------- total: 97.835062sec

                         user     system      total        real
loop                 0.541292   0.000000   0.541292 (  0.541290)
Stat.stat           12.733344   0.000000  12.733344 ( 12.733348)
File.stat           19.946062   0.000000  19.946062 ( 19.946066)
File.exist?         20.518921   0.000000  20.518921 ( 20.518929)
File.file?          38.138579   0.000000  38.138579 ( 38.138587)
C stat (1_645_000)   6.362458   0.000000   6.362458 (  6.362386)

## rbx with old file_stat primitive

euler:rubinius brian$ rm stat.rbc; TOTAL=1_000 shotgun/rubinius stat.rb 
Rehearsal --------------------------------------------------
loop             0.528784   0.000000   0.528784 (  0.528767)
File.stat       30.653916   0.000000  30.653916 ( 30.653916)
File.file?      31.231470   0.000000  31.231470 ( 31.231460)
FileTest.file?  31.790378   0.000000  31.790378 ( 31.790374)
---------------------------------------- total: 94.204548sec

                     user     system      total        real
loop             0.521969   0.000000   0.521969 (  0.521974)
File.stat       30.686709   0.000000  30.686709 ( 30.686724)
File.file?      31.285714   0.000000  31.285714 ( 31.285719)
FileTest.file?  31.806415   0.000000  31.806415 ( 31.806424)

## memory with FFI

require 'benchmark'

total = (ENV['TOTAL'] || 1_000).to_i


Benchmark.bmbm do |x|
  x.report("loop") do
    times = 0
    while times < total
      times += 1
    end
  end
  
  x.report("MemPtr(num)") do
    S = File::Stat::StructStat
    times = 0
    while times < total
      MemoryPointer.new(96) do |m|
        m
      end
      times += 1
    end
  end
  
  x.report("MemPtr(struct)") do
    S = File::Stat::StructStat
    times = 0
    while times < total
      MemoryPointer.new(S) do |m|
        m
      end
      times += 1
    end
  end

  x.report("Struct") do
    S = File::Stat::StructStat
    m = MemoryPointer.new S
    times = 0
    while times < total
      S.new m
      times += 1
    end
  end
end

## results

euler:rubinius brian$ rm memory.rbc; TOTAL=100_000 shotgun/rubinius memory.rb 
Rehearsal --------------------------------------------------
loop             0.006613   0.000000   0.006613 (  0.006615)
MemPtr(num)      1.170544   0.000000   1.170544 (  1.170535)
MemPtr(struct)   1.246660   0.000000   1.246660 (  1.246643)
Struct           0.197862   0.000000   0.197862 (  0.197812)
----------------------------------------- total: 2.621679sec

                     user     system      total        real
loop             0.006349   0.000000   0.006349 (  0.006370)
MemPtr(num)      1.107966   0.000000   1.107966 (  1.107970)
MemPtr(struct)   1.222053   0.000000   1.222053 (  1.222051)
Struct           0.183214   0.000000   0.183214 (  0.183211)