Module Netbuffer

module Netbuffer: sig .. end

A Netbuffer.t is a buffer that can grow and shrink dynamically.

type t

val create : int -> t

Creates a netbuffer which allocates initially this number of bytes. The logical length is zero.

val contents : t -> string

Returns the contents of the buffer as fresh string.

val length : t -> int

Returns the logical length of the buffer

Extracting strings

val get : t -> int -> char

get nb pos: Get the character at pos

val nth : t -> int -> char

Alias for get

val sub : t -> int -> int -> string

sub nb k n: returns the n characters starting at position n from netbuffer nb as fresh string

val blit_to_string : t -> int -> string -> int -> int -> unit

blit_to_string nb srcpos dest destpos len: Copies the len bytes at position srcpos from nb to the string dest at position destpos.

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

Compatibility name for blit_to_string, now deprecated

Appending strings

val add_string : t -> string -> unit

add_string nb s: Adds a copy of the string s to the logical end of the netbuffer nb. If necessary, nb grows.

val add_sub_string : t -> string -> int -> int -> unit

add_sub_string nb s k n: Adds the substring of s starting at position k with length n to the logical end of the netbuffer nb. If necessary, nb grows.

This is semantically the same as add_string nb (String.sub s k n), but the extra copy is avoided.

val add_substring : t -> string -> int -> int -> unit

Alias for add_sub_string

val add_char : t -> char -> unit

add_char nb c: Adds a single char at the end of the buffer

val add_char_2 : t -> char -> char -> unit

add_char_2 nb c1 c2: Adds two chars at the end of the buffer

val add_char_4 : t -> char -> char -> char -> char -> unit

add_char_4 nb c1 c2 c3 c4: Adds four chars at the end of the buffer

val add_inplace : ?len:int -> t -> (string -> int -> int -> int) -> int

add_inplace nb f: Calls the function f to add bytes to the netbuffer nb. The arguments of f are the buffer, the position in the buffer, and the maximum length. The function f must return the actual number of added bytes; this number is also returned by add_inplace.

Example: let n = add_inplace nb (Pervasives.input ch)

The argument len is the number of bytes to add (second argument of f). It defaults to the number of free bytes in the buffer after space for at least one byte has been allocated.

val add_buffer : t -> t -> unit

add_buffer nb1 nb2: Adds the contents of nb2 to the end of nb1

val area_for_additions : ?len:int -> t -> string * int * int

val advance : t -> int -> unit

These two functions work together, so that the effect of add_inplace can be obtained in two steps. First, the user calls

        let (s,pos,len) = area_for_additions nb

to get the area where to put new data of length n, with n <= len. After this the data is made valid by

        advance n

Inserting strings

val insert_string : t -> int -> string -> unit

insert_string nb p s: Inserts the value of string s at position p into the netbuffer nb

val insert_sub_string : t -> int -> string -> int -> int -> unit

insert_string nb p s k n: Inserts a substring of string s at position p into the netbuffer nb. The substring is denoted by position k and has length n

val insert_char : t -> int -> char -> unit

insert_char nb p c: Inserts character c at position p into the netbuffer nb

Overwriting strings

val set : t -> int -> char -> unit

set nb pos c: Sets the character at pos to c

val put_string : t -> int -> string -> unit

put_string nb pos s: Copies the string s to the position pos of netbuffer nb

val blit_from_string : string -> int -> t -> int -> int -> unit

blit_from_string src srcpos dest destpos len: Copies the len bytes at position srcpos from the string src to the netbuffer dest at position destpos.

It is possible to copy the string beyond the end of the buffer. The buffer is automatically enlarged in this case.

Deleting

val delete : t -> int -> int -> unit

delete nb k n: Deletes the n bytes at position k of netbuffer nb in-place.

The netbuffer does not shrink, however, i.e. the free space is not given back to the memory manager.

val clear : t -> unit

Deletes all contents from the buffer. As delete, the netbuffer does not shrink.

val reset : t -> unit

Empty the buffer, deallocate the internal string, and replace it with a new string of length n that was allocated by Netbuffer.create n.

val try_shrinking : t -> unit

try_shrinking nb: If the length of the buffer is less than half of the allocated space, the netbuffer is reallocated in order to save memory.

Searching

val index_from : t -> int -> char -> int

index_from nb k c: Searches the character c in the netbuffer beginning at position k. If found, the position of the left-most occurence is returned. Otherwise, Not_found is raised.

Memory

val blit_to_memory : t -> int -> Netsys_mem.memory -> int -> int -> unit

blit_to_memory nb srcpos dest destpos len: Copies the len bytes at position srcpos from nb to the membuffer dest at position destpos.

val add_sub_memory : t -> Netsys_mem.memory -> int -> int -> unit

Same as add_sub_string, but gets data from a memory buffer

Miscelleneous

val unsafe_buffer : t -> string

Warning! This is a low-level function! Returns the current string that internally holds the buffer. The byte positions 0 to length - 1 actually store the contents of the buffer. You can directly read and modify the buffer. Note that there is no protection if you read or write positions beyond the length of the buffer.

val print_buffer : t -> unit

For the toploop

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