hphp/hack/src/utils/php_escaping.ml

   1 (*
   2  * Copyright (c) 2015, Facebook, Inc.
   3  * All rights reserved.
   4  *
   5  * This source code is licensed under the MIT license found in the
   6  * LICENSE file in the "hack" directory of this source tree.
   7  *
   8  *)
   9
  10 (* Implementation of string escaping stuff. Ugggggggh.
  11  * See http://php.net/manual/en/language.types.string.php *)
  12
  13 open Hh_prelude
  14
  15 let is_printable c =
  16   let open Char in
  17   c >= ' ' && c <= '~'
  18
  19 let is_lit_printable c =
  20   let open Char in
  21   is_printable c && c <> '\\' && c <> '\"'
  22
  23 let escape_char = function
  24   | '\n' -> "\\n"
  25   | '\r' -> "\\r"
  26   | '\t' -> "\\t"
  27   | '\\' -> "\\\\"
  28   | '"' -> "\\\""
  29   | '$' -> "$"
  30   | c when is_lit_printable c -> String.make 1 c
  31   | c -> Printf.sprintf "\\%03o" (Char.to_int c)
  32
  33 let escape ?(f = escape_char) s =
  34   let buf = Buffer.create (String.length s) in
  35   Stdlib.String.iter (fun c -> Buffer.add_string buf @@ f c) s;
  36   Buffer.contents buf