Module Lwt_bytes

module Lwt_bytes : sig..end

Byte arrays


type t = 
  (char, Bigarray.int8_unsigned_elt, Bigarray.c_layout)
  Bigarray.Array1.t

Type of array of bytes.

val create : int -> t

Creates a new byte array of the given size.

val length : t -> int

Returns the length of the given byte array.

Access

val get : t -> int -> char

get buffer offset returns the byte at offset offset in buffer.

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

get buffer offset value changes the value of the byte at offset offset in buffer to value.

val unsafe_get : t -> int -> char

Same as Lwt_bytes.​get but without bound checking.

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

Same as Lwt_bytes.​set but without bound checking.

Conversions

val of_bytes : Bytes.t -> t

of_bytes buf returns a newly allocated byte array with the same contents as buf.

val of_string : string -> t

of_string buf returns a newly allocated byte array with the same contents as buf.

val to_bytes : t -> Bytes.t

to_bytes buf returns newly allocated bytes with the same contents as buf.

val to_string : t -> string

to_string buf returns a newly allocated string with the same contents as buf.

Copying

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

blit buf1 ofs1 buf2 ofs2 len copy len bytes from buf1 starting at offset ofs1 to buf2 starting at offset ofs2.

val blit_from_bytes : Bytes.t -> int -> t -> int -> int -> unit

Same as blit but the first buffer is a string instead of a byte array.

val blit_to_bytes : t -> int -> Bytes.t -> int -> int -> unit

Same as blit but the second buffer is a string instead of a byte array.

val unsafe_blit : t -> int -> t -> int -> int -> unit

Same as Lwt_bytes.​blit but without bound checking.

val unsafe_blit_from_bytes : Bytes.t -> int -> t -> int -> int -> unit

Same as blit_string_bytes but without bound checking.

val unsafe_blit_to_bytes : t -> int -> Bytes.t -> int -> int -> unit

Same as blit_bytes_string but without bound checking.

val proxy : t -> int -> int -> t

proxy buffer offset length creates a ``proxy''. The returned byte array share the data of buffer but with different bounds.

val extract : t -> int -> int -> t

extract buffer offset length creates a new byte array of length length and copy the length bytes of buffer at offset into it.

val copy : t -> t

copy buffer creates a copy of the given byte array.

Filling

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

fill buffer offset length value puts value in all length bytes of buffer starting at offset offset.

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

Same as Lwt_bytes.​fill but without bound checking.

IOs

The following functions does the same as the functions in Lwt_unix except that they use byte arrays instead of strings.

val read : Lwt_unix.file_descr -> t -> int -> int -> int Lwt.t
val write : Lwt_unix.file_descr -> t -> int -> int -> int Lwt.t
val recv : 
  Lwt_unix.file_descr ->
  t -> int -> int -> Unix.msg_flag list -> int Lwt.t
val send : 
  Lwt_unix.file_descr ->
  t -> int -> int -> Unix.msg_flag list -> int Lwt.t
val recvfrom : 
  Lwt_unix.file_descr ->
  t ->
  int -> int -> Unix.msg_flag list -> (int * Unix.sockaddr) Lwt.t
val sendto : 
  Lwt_unix.file_descr ->
  t ->
  int -> int -> Unix.msg_flag list -> Unix.sockaddr -> int Lwt.t
type io_vector = {
  iov_buffer: t;  iov_offset: int;  iov_length: int;}
val io_vector : buffer:t -> offset:int -> length:int -> io_vector
val recv_msg : 
  socket:Lwt_unix.file_descr ->
  io_vectors:io_vector list ->
  (int * Unix.file_descr list) Lwt.t

This call is not available on windows.

val send_msg : 
  socket:Lwt_unix.file_descr ->
  io_vectors:io_vector list ->
  fds:Unix.file_descr list -> int Lwt.t

This call is not available on windows.

Memory mapped files

val map_file : 
  fd:Unix.file_descr ->
  ?pos:int64 -> shared:bool -> ?size:int -> unit -> t

map_file ~fd ?pos ~shared ?size () maps the file descriptor fd to an array of bytes.

val mapped : t -> bool

mapped buffer returns true iff buffer is a memory mapped file.

type advice =  | MADV_NORMAL | MADV_RANDOM | MADV_SEQUENTIAL | MADV_WILLNEED | MADV_DONTNEED

Type of advise that can be sent to the kernel by the program. See the manual madvise(2) for a description of each advices.

val madvise : t -> int -> int -> advice -> unit

madvise buffer pos len advice advise the kernel about how the program is going to use the part of the memory mapped file between pos and pos + len.

This call is not available on windows.

val page_size : int

Size of pages.

val mincore : t -> int -> bool array -> unit

mincore buffer offset states tests whether the given pages are in the system memory (the RAM). The offset argument must be a multiple of Lwt_bytes.​page_size. states is used to store the result; each cases is true if the corresponding page in the RAM and false otherwise.

This call is not available on windows.

val wait_mincore : t -> int -> unit Lwt.t

wait_mincore buffer offset waits until the page containing the byte at offset offset in the the RAM.

This functions is not available on windows.