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Edit File: buffer.mli

(**************************************************************************) (* *) (* OCaml *) (* *) (* 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 Lesser General Public License version 2.1, with the *) (* special exception on linking described in the file LICENSE. *) (* *) (**************************************************************************) (** Extensible buffers. This module implements buffers that automatically expand as necessary. It provides accumulative concatenation of strings in quasi-linear time (instead of quadratic time when strings are concatenated pairwise). *) type t (** The abstract type of buffers. *) val create : int -> t (** [create n] returns a fresh buffer, initially empty. The [n] parameter is the initial size of the internal byte sequence that holds the buffer contents. That byte sequence is automatically reallocated when more than [n] characters are stored in the buffer, but shrinks back to [n] characters when [reset] is called. For best performance, [n] should be of the same order of magnitude as the number of characters that are expected to be stored in the buffer (for instance, 80 for a buffer that holds one output line). Nothing bad will happen if the buffer grows beyond that limit, however. In doubt, take [n = 16] for instance. If [n] is not between 1 and {!Sys.max_string_length}, it will be clipped to that interval. *) val contents : t -> string (** Return a copy of the current contents of the buffer. The buffer itself is unchanged. *) val to_bytes : t -> bytes (** Return a copy of the current contents of the buffer. The buffer itself is unchanged. @since 4.02 *) val sub : t -> int -> int -> string (** [Buffer.sub b off len] returns a copy of [len] bytes from the current contents of the buffer [b], starting at offset [off]. Raise [Invalid_argument] if [srcoff] and [len] do not designate a valid range of [b]. *) val blit : t -> int -> bytes -> int -> int -> unit (** [Buffer.blit src srcoff dst dstoff len] copies [len] characters from the current contents of the buffer [src], starting at offset [srcoff] to [dst], starting at character [dstoff]. Raise [Invalid_argument] if [srcoff] and [len] do not designate a valid range of [src], or if [dstoff] and [len] do not designate a valid range of [dst]. @since 3.11.2 *) val nth : t -> int -> char (** Get the n-th character of the buffer. Raise [Invalid_argument] if index out of bounds *) val length : t -> int (** Return the number of characters currently contained in the buffer. *) val clear : t -> unit (** Empty the buffer. *) val reset : t -> unit (** Empty the buffer and deallocate the internal byte sequence holding the buffer contents, replacing it with the initial internal byte sequence of length [n] that was allocated by {!Buffer.create} [n]. For long-lived buffers that may have grown a lot, [reset] allows faster reclamation of the space used by the buffer. *) val add_char : t -> char -> unit (** [add_char b c] appends the character [c] at the end of buffer [b]. *) val add_string : t -> string -> unit (** [add_string b s] appends the string [s] at the end of buffer [b]. *) val add_bytes : t -> bytes -> unit (** [add_bytes b s] appends the byte sequence [s] at the end of buffer [b]. @since 4.02 *) val add_substring : t -> string -> int -> int -> unit (** [add_substring b s ofs len] takes [len] characters from offset [ofs] in string [s] and appends them at the end of buffer [b]. *) val add_subbytes : t -> bytes -> int -> int -> unit (** [add_subbytes b s ofs len] takes [len] characters from offset [ofs] in byte sequence [s] and appends them at the end of buffer [b]. @since 4.02 *) val add_substitute : t -> (string -> string) -> string -> unit (** [add_substitute b f s] appends the string pattern [s] at the end of buffer [b] with substitution. The substitution process looks for variables into the pattern and substitutes each variable name by its value, as obtained by applying the mapping [f] to the variable name. Inside the string pattern, a variable name immediately follows a non-escaped [$] character and is one of the following: - a non empty sequence of alphanumeric or [_] characters, - an arbitrary sequence of characters enclosed by a pair of matching parentheses or curly brackets. An escaped [$] character is a [$] that immediately follows a backslash character; it then stands for a plain [$]. Raise [Not_found] if the closing character of a parenthesized variable cannot be found. *) val add_buffer : t -> t -> unit (** [add_buffer b1 b2] appends the current contents of buffer [b2] at the end of buffer [b1]. [b2] is not modified. *) val add_channel : t -> in_channel -> int -> unit (** [add_channel b ic n] reads at most [n] characters from the input channel [ic] and stores them at the end of buffer [b]. Raise [End_of_file] if the channel contains fewer than [n] characters. In this case, the characters are still added to the buffer, so as to avoid loss of data. *) val output_buffer : out_channel -> t -> unit (** [output_buffer oc b] writes the current contents of buffer [b] on the output channel [oc]. *) val truncate : t -> int -> unit (** [truncate b len] truncates the length of [b] to [len] Note: the internal byte sequence is not shortened. Raise [Invalid_argument] if [len < 0] or [len > length b]. @since 4.05.0 *)