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Library
Module
Module type
Parameter
Class
Class type
Extensible buffers.
This module implements buffers that automatically expand as necessary. It provides accumulative concatenation of strings in linear time (instead of quadratic time when strings are concatenated pairwise). For example:
let concat_strings ss =
let b = Buffer.create 16 in
List.iter (Buffer.add_string b) ss;
Buffer.contents b
Unsynchronized accesses
Unsynchronized accesses to a buffer may lead to an invalid buffer state. Thus, concurrent accesses to a buffer must be synchronized (for instance with a Mutex.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.
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.
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.createn. For long-lived buffers that may have grown a lot, reset allows faster reclamation of the space used by the buffer.
if ofs and len do not designate a valid range of s.
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 $.
The functions in this section append binary encodings of integers to buffers.
Little-endian (resp. big-endian) encoding means that least (resp. most) significant bytes are stored first. Big-endian is also known as network byte order. Native-endian encoding is either little-endian or big-endian depending on Sys.big_endian.
32-bit and 64-bit integers are represented by the int32 and int64 types, which can be interpreted either as signed or unsigned numbers.
8-bit and 16-bit integers are represented by the int type, which has more bits than the binary encoding. Functions that encode these values truncate their inputs to their least significant bytes.