module Buffer: sig .. end
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
The abstract type of buffers.
val create : int -> t
returns a fresh buffer, initially empty.
parameter is the initial size of the internal string
that holds the buffer contents. That string is automatically
reallocated when more than
characters are stored in the buffer,
but shrinks back to
For best performance,
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
is not between 1 and
, 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 sub : t -> int -> int -> string
Buffer.sub b off len returns (a copy of) the substring of the
current contents of the buffer
b starting at offset
off of length
len bytes. May raise
Invalid_argument if out of bounds request. The
buffer itself is unaffected.
val blit : t -> int -> string -> int -> int -> unit
Buffer.blit src srcoff dst dstoff len copies
len characters from
the current contents of the buffer
src, starting at offset
dst, starting at character
len do not designate a valid
src, or if
len do not designate a valid
val nth : t -> int -> char
get the n-th character of the buffer. Raise
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
that was allocated by
For long-lived buffers that may have grown a lot,
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
val add_string : t -> string -> unit
add_string b s appends the string
s at the end of the buffer
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
val add_substitute : t -> (string -> string) -> string -> unit
add_substitute b f s
appends the string pattern
at the end
of the buffer
The substitution process looks for variables into
the pattern and substitutes each variable name by its value, as
obtained by applying the mapping
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
- an arbitrary sequence of characters enclosed by a pair of
matching parentheses or curly brackets.
$ character is a
$ that immediately follows a backslash
character; it then stands for a plain
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
at the end of buffer
b2 is not modified.
val add_channel : t -> Pervasives.in_channel -> int -> unit
add_channel b ic n reads exactly
n character from the
ic and stores them at the end of buffer
End_of_file if the channel contains fewer than
val output_buffer : Pervasives.out_channel -> t -> unit
output_buffer oc b writes the current contents of buffer
on the output channel