package batteries
-
batteries
-
batteriesThread
Library
Module
Module type
Parameter
Class
Class type
Extensible string buffers.
This module implements string 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).
- author Pierre Weis (Base module)
- author Xavier Leroy (Base module)
- author David Teller
- author Dawid Toton
type t = Buffer.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 string that holds the buffer contents. That string 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.
Return a copy of the current contents of the buffer. The buffer itself is unchanged.
- since 2.3.0
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
.
Buffer.blit src srcoff dst dstoff len
copies len
characters from the current contents of the buffer src
, starting at offset srcoff
to string dst
, starting at character dstoff
.
- raises Invalid_argument
if
srcoff
andlen
do not designate a valid substring ofsrc
, or ifdstoff
andlen
do not designate a valid substring ofdst
.
- since 3.11.2
val nth : t -> int -> char
get the n-th character of the buffer.
- raises 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 string holding the buffer contents, replacing it with the initial internal string 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 the buffer b
.
val add_string : t -> string -> unit
add_string b s
appends the string s
at the end of the buffer b
.
add_bytes b s
appends the string s
at the end of the buffer b
.
- since 2.3.0
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 the buffer b
.
add_subbytes b s ofs len
takes len
characters from offset ofs
in byte sequence s
and appends them at the end of the buffer b
.
- since 2.3.0
val add_substitute : t -> (string -> string) -> string -> unit
add_substitute b f s
appends the string pattern s
at the end of the 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$
.
- raises Not_found
if the closing character of a parenthesized variable cannot be found.
add_buffer b1 b2
appends the current contents of buffer b2
at the end of buffer b1
. b2
is not modified.
val add_input : t -> BatInnerIO.input -> int -> unit
add_input b ic n
reads exactly n
character from the input ic
and stores them at the end of buffer b
.
- raises End_of_file
if the channel contains fewer than
n
characters.
val add_channel : t -> BatInnerIO.input -> int -> unit
@obsolete replaced by add_input
val output_buffer : t -> string BatInnerIO.output
output_buffer b
creates an output channel that writes to that buffer, and when closed, returns the contents of the buffer.
val truncate : t -> int -> unit
truncate b len
truncates the length of b
to len
Note: the internal byte sequence is not shortened. Raises Invalid_argument
if len < 0
or len > length b
.
- since 2.7.0 and OCaml 4.05.0
add_utf_8_uchar b u
appends the UTF-8 encoding of u
at the end of buffer b
.
- since 2.8.0 and OCaml 4.06.0
add_utf_16le_uchar b u
appends the UTF-16LE encoding of u
at the end of buffer b
.
- since 2.8.0 and OCaml 4.06.0
add_utf_16be_uchar b u
appends the UTF-16BE encoding of u
at the end of buffer b
.
- since 2.8.0 and OCaml 4.06.0
Boilerplate code
Returns an enumeration of the characters of a buffer.
Contents of the enumeration is unspecified if the buffer is modified after the enumeration is returned.
val print : 'a BatInnerIO.output -> t -> unit