byte_slice: add clear and of_string

src/core/CCByte_slice.ml

@@ -21,6 +21,12 @@ let create ?(off = 0) ?len bs =
 let[@inline] unsafe_of_string ?off ?len s =
   create ?off ?len (Bytes.unsafe_of_string s)
 
+let[@inline] of_string s = create (Bytes.of_string s)
+
+let[@inline] clear self =
+  self.off <- 0;
+  self.len <- 0
+
 let[@inline] len self = self.len
 let[@inline] contents self = Bytes.sub_string self.bs self.off self.len
 

src/core/CCByte_slice.mli

@@ -26,6 +26,12 @@ val unsafe_of_string : ?off:int -> ?len:int -> string -> t
     This is unsafe because mutating the bytes is forbidden
     (just like with {!Bytes.unsafe_of_string} *)
 
+val of_string : string -> t
+(** [of_string s] makes a slice from a copy of [s]. Safe to mutate. *)
+
+val clear : t -> unit
+(** [clear sl] resets [off] and [len] to 0. *)
+
 val len : t -> int
 (** Access the length *)