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 concatenated pairwise).
type
The abstract type of buffers.
val create : int -> tcreate 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 -> stringReturn a copy of the current contents of the buffer. The buffer itself is unchanged.
val sub : t -> int -> int -> stringBuffer.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 nth : t -> int -> charget the n-th character of the buffer. Raise Invalid_argument if
index out of bounds
val length : t -> intReturn the number of characters currently contained in the buffer.
val clear : t -> unitEmpty the buffer.
val reset : t -> unitEmpty 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 -> unitadd_char b c appends the character c at the end of the buffer b.
val add_string : t -> string -> unitadd_string b s appends the string s at the end of the buffer b.
val add_substring : t -> string -> int -> int -> unitadd_substring b s ofs len takes len characters from offset
ofs in string s and appends them at the end of the buffer b.
val add_substitute : t -> (string -> string) -> string -> unitadd_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:
_ characters,$ 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 -> unitadd_buffer b1 b2 appends the current contents of buffer b2
at the end of buffer b1. b2 is not modified.
val add_channel : t -> Stdlib.in_channel -> int -> unitadd_channel b ic n reads exactly n character 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.
val output_buffer : Stdlib.out_channel -> t -> unitoutput_buffer oc b writes the current contents of buffer b
on the output channel oc.