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package batteries
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 t = Buffer.tThe 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.
Return 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 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.
val nth : t -> int -> charget the n-th character of the buffer.
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.
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.
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:
- 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$.
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 -> unitadd_input b ic n reads exactly n character from the input ic and stores them at the end of buffer b.
val add_channel : t -> BatInnerIO.input -> int -> unit@obsolete replaced by add_input
val output_buffer : t -> string BatInnerIO.outputoutput_buffer b creates an output channel that writes to that buffer, and when closed, returns the contents of the buffer.
Boilerplate code
val print : 'a BatInnerIO.output -> t -> unitOn This Page