#6500: add String.init, Bytes.init, Labels couterparts, Stream.of_byte. (Cherry-picked from 15029 on 4.02.)

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@15030 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

stdlib/bytes.ml

@@ -31,6 +31,13 @@ let make n c =
   unsafe_fill s 0 n c;
   s
 
+let init n f =
+  let s = create n in
+  for i = 0 to n - 1 do
+    unsafe_set s i (f i)
+  done;
+  s
+
 let empty = create 0;;
 
 let copy s =

stdlib/bytes.mli

@@ -66,6 +66,12 @@ val make : int -> char -> bytes
 
     Raise [Invalid_argument] if [n < 0] or [n > ]{!Sys.max_string_length}. *)
 
+val init : int -> (int -> char) -> bytes
+(** [Bytes.init n f] returns a fresh byte sequence of length [n],
+    with character [i] initialized to the result of [f i].
+
+    Raise [Invalid_argument] if [n < 0] or [n > ]{!Sys.max_string_length}. *)
+
 val empty : bytes
 (** A byte sequence of size 0. *)
 

stdlib/bytesLabels.mli

@@ -40,6 +40,12 @@ val make : int -> char -> bytes
 
     Raise [Invalid_argument] if [n < 0] or [n > ]{!Sys.max_string_length}. *)
 
+val init : int -> (int -> char) -> bytes
+(** [init n f] returns a fresh byte sequence of length [n],
+    with character [i] initialized to the result of [f i].
+
+    Raise [Invalid_argument] if [n < 0] or [n > ]{!Sys.max_string_length}. *)
+
 val empty : bytes
 (** A byte sequence of size 0. *)
 

stdlib/stream.ml

@@ -159,6 +159,15 @@ let of_string s =
     else None)
 ;;
 
+let of_bytes s =
+  let count = ref 0 in
+  from (fun _ ->
+    let c = !count in
+    if c < Bytes.length s
+    then (incr count; Some (Bytes.get s c))
+    else None)
+;;
+
 let of_channel ic =
   {count = 0;
    data = Sbuffio {ic = ic; buff = Bytes.create 4096; len = 0; ind = 0}}

stdlib/stream.mli

@@ -46,6 +46,9 @@ val of_list : 'a list -> 'a t
 val of_string : string -> char t
 (** Return the stream of the characters of the string parameter. *)
 
+val of_bytes : bytes -> char t
+(** Return the stream of the characters of the bytes parameter. *)
+
 val of_channel : in_channel -> char t
 (** Return the stream of the characters read from the input channel. *)
 

stdlib/string.ml

@@ -27,6 +27,7 @@ external unsafe_fill : bytes -> int -> int -> char -> unit
 module B = Bytes
 
 let make = (Obj.magic B.make : int -> char -> string)
+let init = (Obj.magic B.init : int -> (int -> char) -> string)
 let copy = (Obj.magic B.copy : string -> string)
 let sub = (Obj.magic B.sub : string -> int -> int -> string)
 let fill = B.fill

stdlib/string.mli

@@ -80,6 +80,12 @@ val make : int -> char -> string
 
    Raise [Invalid_argument] if [n < 0] or [n > ]{!Sys.max_string_length}. *)
 
+val init : int -> (int -> char) -> string
+(** [String.init n f] returns a string of length [n],
+    with character [i] initialized to the result of [f i].
+
+   Raise [Invalid_argument] if [n < 0] or [n > ]{!Sys.max_string_length}. *)
+
 val copy : string -> string
 (** Return a copy of the given string. *)
 

stdlib/stringLabels.mli

@@ -46,6 +46,12 @@ val make : int -> char -> string
 
    Raise [Invalid_argument] if [n < 0] or [n > ]{!Sys.max_string_length}. *)
 
+val init : int -> (int -> char) -> string
+(** [init n f] returns a string of length [n],
+    with character [i] initialized to the result of [f i].
+
+   Raise [Invalid_argument] if [n < 0] or [n > ]{!Sys.max_string_length}. *)
+
 val copy : string -> string
 (** Return a copy of the given string. *)