faster splitter

[qznc via Digitalmars-d]

I played around with the benchmark. Some more numbers:

$ make ldc
ldmd2 -O -release -inline -noboundscheck *.d -ofbenchmark.ldc
./benchmark.ldc
E: wrong result with Chris find
E: wrong result with Chris find
E: wrong result with Chris find
     std find: 153 ±25    +66 (1934)  -15 (7860)
  manual find: 122 ±28    +80 (1812)  -17 (8134)
    qznc find: 125 ±16    +18 (4644)  -15 (5126)
   Chris find: 148 ±29    +75 (1976)  -18 (7915)
  Andrei find: 114 ±23   +100 (1191)  -13 (8770)
  (avg slowdown vs fastest; absolute deviation)
$ make dmd
dmd -O -release -inline -noboundscheck *.d -ofbenchmark.dmd
./benchmark.dmd
E: wrong result with Chris find
E: wrong result with Chris find
E: wrong result with Chris find
     std find: 160 ±27    +44 (3162)  -20 (6709)
  manual find: 148 ±28    +54 (2701)  -19 (7178)
    qznc find: 102 ±3     +27 ( 766)   -1 (9136)
   Chris find: 175 ±30    +55 (2796)  -21 (7106)
  Andrei find: 122 ±22    +46 (2554)  -14 (7351)
  (avg slowdown vs fastest; absolute deviation)

The additional numbers on the right are the ±MAD separated by 
above or below the mean. For example Andrei find with ldc:

   Andrei find: 114 ±23   +100 (1191)  -13 (8770)

The mean slowdown is 114, which means 14% slower than the fastest 
one. The mean absolute deviation (MAD) is 23. More precisely, the 
mean deviation above the mean slowdown of 103 is 100 and -13 
below the mean slowdown. 1191 of the 10000 runs were above the 
mean slowdown and 8770 below. The 39 missing runs are equal to 
the mean slowdown.

What bothers me is that changing the alphabet changes the numbers 
so much. Currently, if you restrict the alphabets for haystack 
and needle, the numbers change. The benchmark already does a 
random subset on each run, but there is definitely a bias.