type t
val create : int -> t
create 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 -> string
Return a copy of the current contents of the buffer. The buffer itself is unchanged.
val length : t -> int
Return the number of characters currently contained in the buffer.
val clear : t -> unit
val reset : t -> unit
Empty 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 create n.
For long-lived buffers that may have grown a lot, reset allows
faster reclaimation 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 b.
val add_string : t -> string -> unit
add_string b s appends the string s at the end of
the buffer b.
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 b.
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 -> in_channel -> int -> unit
add_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 : out_channel -> t -> unit
output_buffer oc b writes the current contents of buffer b
on the output channel oc.
Bufferval add_subbuffer : t -> t -> int -> int -> unit
add_subbuffer dst src pos len appends the sub_part of buffer
src starting at position pos and of length len to
the buffer dst. src is not modified. Raise Invalid_argument
if pos and len do not designate a valid sub_part of src
val sub : t -> int -> int -> unit
sub b pos len modify the buffer in order its content
to designate the substring of the initial content,
starting at offset pos and of length len. This function
does not copy nor create strings. Raise Invalid_argument
if pos and len do not designate a valid sub_part of the buffer
val buffer : t -> string*int
buffer b gives the internal string used by the buffer and the
starting active posistion. It can be used in conjunction with
sub when doing write in order to avoid unnecessary copy.
let len = length b in
let str, pos = buffer b in
let nb_written = write fds str pos len in
sub b nb_written (len - nb_written)
val before_read : t -> int -> string*int
val after_read : t -> int -> unit
before_read b len can be used if you want to do a read directly
inside a buffer for avoiding copy. You should use a sequence
like this :
let str, pos = before_read b len in let nb_read = read fds str pos len in after_read b nb_read
You should always use
before_read and after_read together.
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