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by test9753
2445 days ago
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Beating Decades of Optimized C with 27 Lines of Ocaml: type t = { mutable words: int; mutable chars: int; mutable lines: int; mutable in_word: bool ; mutable finished: bool};;
let () =
match Core.Sys.argv with
| [| prog_name |] -> Core.Printf.eprintf "Usage: %s file1 file2 ...\n" prog_name
| _ -> (
let args = Core.Array.slice Core.Sys.argv 1 @@ Core.Array.length Core.Sys.argv in
let buf_size = 65536 in (* 64 KB -> Caml IO buffer size *)
let buf = Core.Bytes.create buf_size in
Core.Array.fold args ~init:() ~f:(fun _ file ->
Core.In_channel.with_file file ~f:(fun in_ch ->
let c = { words = 0; chars = 0; lines = 0; in_word = false; finished = false } in
let set_words () = if c.in_word then c.words <- c.words + 1 in
while not c.finished do
let len = Core.In_channel.input in_ch ~buf ~pos:0 ~len:buf_size |> Core.Int.to_int in
if len > 0 then (
for i = 0 to (len - 1) do
match (Core.Caml.Bytes.get buf i) with
| ' ' | '\t' | '\r' -> (c.chars <- c.chars + 1; set_words (); c.in_word <- false)
| '\n' -> (c.chars <- c.chars + 1; set_words (); c.in_word <- false; c.lines <- c.lines + 1)
| _ -> (c.chars <- c.chars + 1; c.in_word <- true)
done
) else ( c.finished <- true )
done;
set_words ();
Core.Printf.printf "%s -> lines: %d, words: %d, characters: %d\n" file c.lines c.words c.chars)))
;;
Testing: $ ls -lh test_file.txt
-rw-r--r-- 1 user group 508M Oct 16 12:01 test_file.txt
$ time wc test_file.txt
4863460 54621760 532480000 test_file.txt
real 0m3.368s
user 0m3.137s
sys 0m0.195s
#Ocaml version:
$ time ./wcl.native test_file.txt
test_file.txt -> lines: 4863460, words: 54621760, characters: 532480000
real 0m2.480s
user 0m2.345s
sys 0m0.123s
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