ocaml/stdlib/buffer.ml

83 lines
2.8 KiB
OCaml

(***********************************************************************)
(* *)
(* Objective Caml *)
(* *)
(* Pierre Weis and Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
(* *)
(* Copyright 1999 Institut National de Recherche en Informatique et *)
(* en Automatique. All rights reserved. This file is distributed *)
(* under the terms of the GNU Library General Public License, with *)
(* the special exception on linking described in file ../LICENSE. *)
(* *)
(***********************************************************************)
(* Extensible buffers *)
type t =
{mutable buffer : string;
mutable position : int;
mutable length : int;
initial_buffer : string}
let create n =
let n = if n < 1 then 1 else n in
let n = if n > Sys.max_string_length then Sys.max_string_length else n in
let s = String.create n in
{buffer = s; position = 0; length = n; initial_buffer = s}
let contents b = String.sub b.buffer 0 b.position
let length b = b.position
let clear b = b.position <- 0
let reset b =
b.position <- 0; b.buffer <- b.initial_buffer;
b.length <- String.length b.buffer
let resize b more =
let len = b.length in
let new_len = ref len in
while b.position + more > !new_len do new_len := 2 * !new_len done;
if !new_len > Sys.max_string_length then begin
if b.position + more <= Sys.max_string_length
then new_len := Sys.max_string_length
else failwith "Buffer.add: cannot grow buffer"
end;
let new_buffer = String.create !new_len in
String.blit b.buffer 0 new_buffer 0 b.position;
b.buffer <- new_buffer;
b.length <- !new_len
let add_char b c =
let pos = b.position in
if pos >= b.length then resize b 1;
b.buffer.[pos] <- c;
b.position <- pos + 1
let add_substring b s offset len =
if offset < 0 || len < 0 || offset > String.length s - len
then invalid_arg "Buffer.add_substring";
let new_position = b.position + len in
if new_position > b.length then resize b len;
String.blit s offset b.buffer b.position len;
b.position <- new_position
let add_string b s =
let len = String.length s in
let new_position = b.position + len in
if new_position > b.length then resize b len;
String.blit s 0 b.buffer b.position len;
b.position <- new_position
let add_buffer b bs =
add_substring b bs.buffer 0 bs.position
let add_channel b ic len =
if b.position + len > b.length then resize b len;
really_input ic b.buffer b.position len;
b.position <- b.position + len
let output_buffer oc b =
output oc b.buffer 0 b.position