Source file batPrintf.ml

(*
 * BatPrintf - Extended Printf module
 * Copyright (C) 2008 David Teller (contributor)
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version,
 * with the special exception on linking described in file LICENSE.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *)


(**
   {6 Printf}

   A reimplementation of Printf (with a few additional functions) based
   on [output].    We provide an internal signature to limit the dangers
   of {!Obj.magic}.

   {b Note} this module is inlined because of circular dependencies (themselves
   caused by the legacy definition of a function {!printf} in module {!BatIO}).
*)

open BatInnerIO

external format_float: string -> float -> string
  = "caml_format_float"
external format_int: string -> int -> string
  = "caml_format_int"
external format_int32: string -> int32 -> string
  = "caml_int32_format"
external format_nativeint: string -> nativeint -> string
  = "caml_nativeint_format"
external format_int64: string -> int64 -> string
  = "caml_int64_format"

module Sformat = struct

  type index;;

  external unsafe_index_of_int : int -> index = "%identity";;
  let index_of_int i =
    if i >= 0 then unsafe_index_of_int i
    else failwith ("index_of_int: negative argument " ^ string_of_int i);;
  external int_of_index : index -> int = "%identity";;

  let add_int_index i idx = index_of_int (i + int_of_index idx);;
  let succ_index = add_int_index 1;;

  let length fmt = String.length (string_of_format fmt)
  let get fmt i = String.get (string_of_format fmt) i
  let unsafe_get fmt i = String.unsafe_get (string_of_format fmt) i
  let unsafe_to_string = string_of_format
  let sub fmt idx len =
    String.sub (unsafe_to_string fmt) (int_of_index idx) len;;
  let to_string fmt = sub fmt (unsafe_index_of_int 0) (length fmt);;

end;;

let bad_conversion sfmt i c =
  invalid_arg
    ("printf: bad conversion %" ^ String.make 1 c ^ ", at char number " ^
     string_of_int i ^ " in format string ``" ^ sfmt ^ "''");;

let bad_conversion_format fmt i c =
  bad_conversion (Sformat.to_string fmt) i c;;

let incomplete_format fmt =
  invalid_arg
    ("printf: premature end of format string ``" ^
     Sformat.to_string fmt ^ "''");;

(* Parses a string conversion to return the specified length and the padding direction. *)
let parse_string_conversion sfmt =
  let rec parse neg i =
    if i >= String.length sfmt then (0, neg) else
      match String.unsafe_get sfmt i with
      | '1'..'9' ->
        (int_of_string
           (String.sub sfmt i (String.length sfmt - i - 1)),
         neg)
      | '-' -> parse true (succ i)
      | _   -> parse neg  (succ i) in
  try parse false 1 with Failure _ -> bad_conversion sfmt 0 's'

(* Pad a (sub) string into a blank string of length [p],
   on the right if [neg] is true, on the left otherwise. *)
let pad_string pad_char p neg s i len =
  if p = len && i = 0 then s else
  if p <= len then String.sub s i len else
    let res = Bytes.make p pad_char in
    if neg
    then Bytes.blit_string s i res 0 len
    else Bytes.blit_string s i res (p - len) len;
    Bytes.unsafe_to_string res

(* Format a string given a %s format, e.g. %40s or %-20s.
   To do: ignore other flags (#, +, etc)? *)
let format_string sfmt s =
  let (p, neg) = parse_string_conversion sfmt in
  pad_string ' ' p neg s 0 (String.length s);;

(* Extract a format string out of [fmt] between [start] and [stop] inclusive.
   '*' in the format are replaced by integers taken from the [widths] list.
   extract_format returns a string. *)
let extract_format fmt start stop widths =
  let start = succ start in
  let b = Buffer.create (stop - start + 10) in
  Buffer.add_char b '%';
  let rec fill_format i widths =
    if i <= stop then
      match (Sformat.unsafe_get fmt i, widths) with
      | ('*', h :: t) ->
        Buffer.add_string b (string_of_int h);
        let i = succ i in
        fill_format i t
      | ('*', []) ->
        assert false (* should not happen *)
      | (c, _) ->
        Buffer.add_char b c; fill_format (succ i) widths in
  fill_format start (List.rev widths);
  Buffer.contents b;;

let extract_format_int conv fmt start stop widths =
  let sfmt = extract_format fmt start stop widths in
  match conv with
  | 'n' | 'N' ->
    let sfmt = Bytes.of_string sfmt in
    Bytes.set sfmt (Bytes.length sfmt - 1) 'u';
    Bytes.unsafe_to_string sfmt
  | _ -> sfmt;;

(* Returns the position of the next character following the meta format
   string, starting from position [i], inside a given format [fmt].
   According to the character [conv], the meta format string is
   enclosed by the delimitors %{ and %} (when [conv = '{']) or %( and
   %) (when [conv = '(']). Hence, [sub_format] returns the index of
   the character following the [')'] or ['}'] that ends the meta format,
   according to the character [conv]. *)
let sub_format incomplete_format bad_conversion_format conv fmt i =
  let len = Sformat.length fmt in
  let rec sub_fmt c i =
    let close = if c = '(' then ')' else (* '{' *) '}' in
    let rec sub j =
      if j >= len then incomplete_format fmt else
        match Sformat.get fmt j with
        | '%' -> sub_sub (succ j)
        | _ -> sub (succ j)
    and sub_sub j =
      if j >= len then incomplete_format fmt else
        match Sformat.get fmt j with
        | '(' | '{' as c ->
          let j = sub_fmt c (succ j) in sub (succ j)
        | '}' | ')' as c ->
          if c = close then succ j else bad_conversion_format fmt i c
        | _ -> sub (succ j) in
    sub i in
  sub_fmt conv i;;

let sub_format_for_printf conv =
  sub_format incomplete_format bad_conversion_format conv;;

let iter_on_format_args fmt add_conv add_char =

  let lim = Sformat.length fmt - 1 in

  let rec scan_flags skip i =
    if i > lim then incomplete_format fmt else
      match Sformat.unsafe_get fmt i with
      | '*' -> scan_flags skip (add_conv skip i 'i')
      | '#' | '-' | ' ' | '+' -> scan_flags skip (succ i)
      | '_' -> scan_flags true (succ i)
      | '0'..'9'
      | '.' -> scan_flags skip (succ i)
      | _ -> scan_conv skip i
  and scan_conv skip i =
    if i > lim then incomplete_format fmt else
      match Sformat.unsafe_get fmt i with
      | '%' | '!' | ',' -> succ i
      | 's' | 'S' | '[' -> add_conv skip i 's'
      | 'c' | 'C' -> add_conv skip i 'c'
      | 'd' | 'i' |'o' | 'u' | 'x' | 'X' | 'N' -> add_conv skip i 'i'
      | 'f' | 'e' | 'E' | 'g' | 'G' | 'F' -> add_conv skip i 'f'
      | 'B' | 'b' -> add_conv skip i 'B'
      | 'a' | 'r' | 't' as conv -> add_conv skip i conv
      | 'l' | 'n' | 'L' as conv ->
        let j = succ i in
        if j > lim then add_conv skip i 'i' else begin
          match Sformat.get fmt j with
          | 'd' | 'i' | 'o' | 'u' | 'x' | 'X' ->
            add_char (add_conv skip i conv) 'i'
          | _c -> add_conv skip i 'i' end
      | '{' as conv ->
        (* Just get a regular argument, skipping the specification. *)
        let i = add_conv skip i conv in
        (* To go on, find the index of the next char after the meta format. *)
        let j = sub_format_for_printf conv fmt i in
        (* Add the meta specification to the summary anyway. *)
        let rec loop i =
          if i < j - 2 then loop (add_char i (Sformat.get fmt i)) in
        loop i;
        (* Go on, starting at the closing brace to properly close the meta
           specification in the summary. *)
        scan_conv skip (j - 1)
      | '(' as conv ->
        (* Use the static format argument specification instead of
           the runtime format argument value: they must have the same type
           anyway. *)
        scan_fmt (add_conv skip i conv)
      | '}' | ')' as conv -> add_conv skip i conv
      | conv -> bad_conversion_format fmt i conv

  and scan_fmt i =
    if i < lim then
      if Sformat.get fmt i = '%'
      then scan_fmt (scan_flags false (succ i))
      else scan_fmt (succ i)
    else i in

  ignore (scan_fmt 0);;

(* Returns a string that summarizes the typing information that a given
   format string contains.
   For instance, [summarize_format_type "A number %d\n"] is "%i".
   It also checks the well-formedness of the format string. *)
let summarize_format_type fmt =
  let len = Sformat.length fmt in
  let b = Buffer.create len in
  let add_char i c = Buffer.add_char b c; succ i in
  let add_conv skip i c =
    if skip then Buffer.add_string b "%_" else Buffer.add_char b '%';
    add_char i c in
  iter_on_format_args fmt add_conv add_char;
  Buffer.contents b;;

module Ac = struct
  type ac = {
    mutable ac_rglr : int;
    mutable ac_skip : int;
    mutable ac_rdrs : int;
  }
end;;

open Ac;;

(* Computes the number of arguments of a format (including flag
   arguments if any). *)
let ac_of_format fmt =
  let ac = { ac_rglr = 0; ac_skip = 0; ac_rdrs = 0; } in
  let incr_ac skip c =
    let inc = if c = 'a' then 2 else 1 in
    if c = 'r' then ac.ac_rdrs <- ac.ac_rdrs + 1;
    if skip
    then ac.ac_skip <- ac.ac_skip + inc
    else ac.ac_rglr <- ac.ac_rglr + inc in
  let add_conv skip i c =
    (* Just finishing a meta format: no additional argument to record. *)
    if c <> ')' && c <> '}' then incr_ac skip c;
    succ i
  and add_char i _c = succ i in

  iter_on_format_args fmt add_conv add_char;
  ac;;

let count_arguments_of_format fmt =
  let ac = ac_of_format fmt in
  ac.ac_rglr + ac.ac_skip + ac.ac_rdrs;;

let list_iter_i f l =
  let rec loop i = function
    | [] -> ()
    | [x] -> f i x (* Tail calling [f] *)
    | x :: xs -> f i x; loop (succ i) xs in
  loop 0 l;;

(* ``Abstracting'' version of kprintf: returns a (curried) function that
   will print when totally applied.
   Note: in the following, we are careful not to be badly caught
   by the compiler optimizations on the representation of arrays. *)
let kapr kpr fmt =
  match count_arguments_of_format fmt with
  | 0 -> kpr fmt [||]
  | 1 -> Obj.magic (fun x ->
           let a = Array.make 1 (Obj.repr 0) in
           a.(0) <- x;
           kpr fmt a)
  | 2 -> Obj.magic (fun x y ->
           let a = Array.make 2 (Obj.repr 0) in
           a.(0) <- x; a.(1) <- y;
           kpr fmt a)
  | 3 -> Obj.magic (fun x y z ->
           let a = Array.make 3 (Obj.repr 0) in
           a.(0) <- x; a.(1) <- y; a.(2) <- z;
           kpr fmt a)
  | 4 -> Obj.magic (fun x y z t ->
           let a = Array.make 4 (Obj.repr 0) in
           a.(0) <- x; a.(1) <- y; a.(2) <- z;
           a.(3) <- t;
           kpr fmt a)
  | 5 -> Obj.magic (fun x y z t u ->
           let a = Array.make 5 (Obj.repr 0) in
           a.(0) <- x; a.(1) <- y; a.(2) <- z;
           a.(3) <- t; a.(4) <- u;
           kpr fmt a)
  | 6 -> Obj.magic (fun x y z t u v ->
           let a = Array.make 6 (Obj.repr 0) in
           a.(0) <- x; a.(1) <- y; a.(2) <- z;
           a.(3) <- t; a.(4) <- u; a.(5) <- v;
           kpr fmt a)
  | nargs ->
    let rec loop i args =
      if i >= nargs then
        let a = Array.make nargs (Obj.repr 0) in
        list_iter_i (fun i arg -> a.(nargs - i - 1) <- arg) args;
        kpr fmt a
      else Obj.magic (fun x -> loop (succ i) (x :: args)) in
    loop 0 [];;

(* Get the index of the next argument to printf. *)
let next_index n = Sformat.succ_index n;;

(* Decode a format string and act on it.
   [fmt] is the printf format string, and [pos] points to a [%] character.
   After consuming the appropriate number of arguments and formatting
   them, one of the five continuations is called:
   [cont_s] for outputting a string (args: arg num, string, next pos)
   [cont_a] for performing a %a action (args: arg num, fn, arg, next pos)
   [cont_t] for performing a %t action (args: arg num, fn, next pos)
   [cont_f] for performing a flush action (args: arg num, next pos)
   [cont_m] for performing a %( action (args: arg num, sfmt, next pos)

   "arg num" is the index in array args of the next argument to printf.
   "next pos" is the position in [fmt] of the first character following
   the %conversion specification in [fmt]. *)

(* Note: here, rather than test explicitly against [Sformat.length fmt]
   to detect the end of the format, we use [Sformat.unsafe_get] and
   rely on the fact that we'll get a "nul" character if we access
   one past the end of the string.  These "nul" characters are then
   caught by the [_ -> bad_conversion] clauses below.
   Don't do this at home, kids. *)
let scan_format fmt args n pos cont_s cont_a cont_t cont_f cont_m =

  let get_arg n =
    Obj.magic (args.(Sformat.int_of_index n)) in

  let rec scan_flags n widths i =
    match Sformat.unsafe_get fmt i with
    | '*' ->
      let (width : int) = get_arg n in
      scan_flags (next_index n) (width :: widths) (succ i)
    | '0'..'9'
    | '.' | '#' | '-' | ' ' | '+' -> scan_flags n widths (succ i)
    | _ -> scan_conv n widths i

  and scan_conv n widths i =
    match Sformat.unsafe_get fmt i with
    | '%' ->
      cont_s n "%" (succ i)
    | 's' | 'S' as conv ->
      let (x : string) = get_arg n in
      let x = if conv = 's' then x else "\"" ^ String.escaped x ^ "\"" in
      let s =
        (* optimize for common case %s *)
        if i = succ pos then x else
          format_string (extract_format fmt pos i widths) x in
      cont_s (next_index n) s (succ i)
    | 'c' | 'C' as conv ->
      let (x : char) = get_arg n in
      let s =
        if conv = 'c' then String.make 1 x else "'" ^ Char.escaped x ^ "'" in
      cont_s (next_index n) s (succ i)
    | 'd' | 'i' | 'o' | 'u' | 'x' | 'X' | 'N' as conv ->
      let (x : int) = get_arg n in
      let s =
        format_int (extract_format_int conv fmt pos i widths) x in
      cont_s (next_index n) s (succ i)
    | 'f' | 'e' | 'E' | 'g' | 'G' ->
      let (x : float) = get_arg n in
      let s = format_float (extract_format fmt pos i widths) x in
      cont_s (next_index n) s (succ i)
    | 'F' ->
      let (x : float) = get_arg n in
      cont_s (next_index n) (string_of_float x) (succ i)
    | 'B' | 'b' ->
      let (x : bool) = get_arg n in
      cont_s (next_index n) (string_of_bool x) (succ i)
    | 'a' ->
      let printer = get_arg n in
      let n = Sformat.succ_index n in
      let arg = get_arg n in
      cont_a (next_index n) printer arg (succ i)
    | 't' ->
      let printer = get_arg n in
      cont_t (next_index n) printer (succ i)
    | 'l' | 'n' | 'L' as conv ->
      begin match Sformat.unsafe_get fmt (succ i) with
        | 'd' | 'i' | 'o' | 'u' | 'x' | 'X' ->
          let i = succ i in
          let s =
            match conv with
            | 'l' ->
              let (x : int32) = get_arg n in
              format_int32 (extract_format fmt pos i widths) x
            | 'n' ->
              let (x : nativeint) = get_arg n in
              format_nativeint (extract_format fmt pos i widths) x
            | _ ->
              let (x : int64) = get_arg n in
              format_int64 (extract_format fmt pos i widths) x in
          cont_s (next_index n) s (succ i)
        | _ ->
          let (x : int) = get_arg n in
          let s = format_int (extract_format_int 'n' fmt pos i widths) x in
          cont_s (next_index n) s (succ i)
      end
    | ',' -> cont_s n "" (succ i)
    | '!' -> cont_f n (succ i)
    | '{' | '(' as conv (* ')' '}' *) ->
      let (xf : ('a, 'b, 'c, 'd, 'e, 'f) format6) = get_arg n in
      let i = succ i in
      let j = sub_format_for_printf conv fmt i in
      if conv = '{' (* '}' *) then
        (* Just print the format argument as a specification. *)
        cont_s
          (next_index n)
          (summarize_format_type xf)
          j else
        (* Use the format argument instead of the format specification. *)
        cont_m (next_index n) xf j
    | (* '(' *) ')' ->
      cont_s n "" (succ i)
    | conv ->
      bad_conversion_format fmt i conv in

  scan_flags n [] (succ pos);;

(*Trimmed-down version of the legacy lib's [mkprintf]. Most of the generality
  is lifted to [output] rather than [mkprintf] itself.*)
let mkprintf k out fmt =

  let rec pr k n fmt v =

    let len = Sformat.length fmt in

    let rec doprn n i =
      if i >= len then Obj.magic (k out)
      else             match Sformat.unsafe_get fmt i with
        | '%' -> scan_format fmt v n i cont_s cont_a cont_t cont_f cont_m
        |  c  -> write out c; doprn n (succ i)
    and cont_s n s i =
      nwrite out s;
      doprn n i
    and cont_a n printer arg i =
      printer out arg;
      doprn n i
    and cont_t n printer i =
      printer out;
      doprn n i
    and cont_f n i =
      flush out;
      doprn n i
    and cont_m n xf i =
      let m = Sformat.add_int_index (count_arguments_of_format xf) n in
      pr (Obj.magic (fun _ -> doprn m i)) n xf v

    in doprn n 0
  in let kpr = pr k (Sformat.index_of_int 0) in
  kapr kpr fmt;;

external identity : 'a -> 'a = "%identity"(*Inlined from [Std] to avoid cyclic dependencies*)
let fprintf out fmt = mkprintf ignore out fmt
let printf      fmt = fprintf stdout fmt
let eprintf     fmt = fprintf stderr fmt
let ifprintf _  fmt = fprintf stdnull fmt
let ksprintf2 k fmt =
  let out = output_string () in
  mkprintf (fun out -> k (close_out out)) out fmt
let kbprintf2 k buf fmt =
  let out = BatBuffer.output_buffer buf in
  mkprintf (fun _out -> k buf) out fmt
let sprintf2 fmt = ksprintf2 (identity) fmt
let bprintf2 buf fmt = kbprintf2 ignore buf fmt
(*
   Other possible implementation of [sprintf2],
   left as example:

   [
   let sprintf2    fmt =
   let out = output_string () in
    mkprintf (fun out -> close_out out) out fmt
   ]
*)
(*
   Other possible implementation of [bprintf2],
   left as example:
   [
   let bprintf2 buf fmt =
   let out = output_buffer buf in
    mkprintf ignore out fmt
   ]*)

type ('a, 'b, 'c) t = ('a, 'b, 'c) format

let kfprintf        = mkprintf
let bprintf         = Printf.bprintf
let sprintf         = Printf.sprintf
let ksprintf        = Printf.ksprintf
let kbprintf        = Printf.kbprintf
let kprintf         = Printf.kprintf

##V<4.2##module CamlinternalPr = Printf.CamlinternalPr