NAME

       Buffer - Extensible buffers.

Module

       Module   Buffer

Documentation

       Module Buffer
        : sig end

       Extensible buffers.

       This  module  implements  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

       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 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.

       val contents : t -> string

       Return a copy of the current contents of the buffer.  The buffer itself is unchanged.

       val to_bytes : t -> bytes

       Return a copy of the current contents of the buffer.  The buffer itself is unchanged.

       Since 4.02

       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 .

       val blit : t -> int -> bytes -> int -> int -> unit

       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 .

       Raise Invalid_argument if srcoff and len do not designate a valid range of  src  ,  or  if
       dstoff and len do not designate a valid range of dst .

       Since 3.11.2

       val nth : t -> int -> char

       Get the n-th character of the buffer. Raise 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 byte sequence holding the buffer contents,
       replacing it with the initial internal byte sequence 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 buffer b .

       val add_string : t -> string -> unit

       add_string b s appends the string s at the end of buffer b .

       val add_bytes : t -> bytes -> unit

       add_bytes b s appends the byte sequence s at the end of buffer b .

       Since 4.02

       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 buffer b .

       val add_subbytes : t -> bytes -> int -> int -> unit

       add_subbytes  b  s  ofs  len  takes  len characters from offset ofs in byte sequence s and
       appends them at the end of buffer b .

       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  $  .   Raise  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 b2 at the end of buffer b1 .  b2
       is not modified.

       val add_channel : t -> Pervasives.in_channel -> int -> unit

       add_channel b ic n reads at most n characters 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.
       In this case, the characters are still added to the buffer, so as to avoid loss of data.

       val output_buffer : Pervasives.out_channel -> t -> unit

       output_buffer oc b writes the current contents of buffer b on the output channel oc .

       val truncate : t -> int -> unit

       truncate b len truncates the length of b to len Note: the internal byte  sequence  is  not
       shortened.  Raise Invalid_argument if len < 0 or len > length b .

       Since 4.05.0