Module `Lwt_bytes`

Byte arrays

type t = (char, Stdlib.Bigarray.int8_unsigned_elt, Stdlib.Bigarray.c_layout) Stdlib.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 get but without bounds checking.

val unsafe_set : t -> int -> char -> unit: Same as set but without bounds checking.

Conversions

val of_bytes : bytes -> 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: 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 copies len bytes from buf1 starting at offset ofs1 to buf2 starting at offset ofs2.

val blit_from_bytes : bytes -> 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 -> 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 blit but without bound checking.

val unsafe_blit_from_bytes : bytes -> int -> t -> int -> int -> unit: Same as Lwt_bytes.blit_from_bytes but without bounds checking.

val unsafe_blit_to_bytes : t -> int -> bytes -> int -> int -> unit: Same as Lwt_bytes.blit_to_bytes but without bounds 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 fill but without bounds checking.

IOs

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: Not implemented on Windows.

val send : Lwt_unix.file_descr -> t -> int -> int -> Unix.msg_flag list -> int Lwt.t: Not implemented on Windows.

val recvfrom : Lwt_unix.file_descr -> t -> int -> int -> Unix.msg_flag list -> (int * Unix.sockaddr) Lwt.t: Not implemented on Windows.

val sendto : Lwt_unix.file_descr -> t -> int -> int -> Unix.msg_flag list -> Unix.sockaddr -> int Lwt.t: Not implemented on Windows.

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

Not implemented on Windows.

deprecated: Use Lwt_unix.Versioned.recv_msg_2.

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

Not implemented on Windows.

deprecated: Use Lwt_unix.Versioned.send_msg_2.

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 | MADV_MERGEABLE | MADV_UNMERGEABLE | MADV_HUGEPAGE | MADV_NOHUGEPAGE: Type of advise that can be sent to the kernel by the program. See the manual madvise(2) for a description of each.

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

madvise buffer pos len advice advises the kernel how the program will use 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 page_size. states is used to store the result; each cases is true if the corresponding page is in RAM and false otherwise.

This call is not available on windows and cygwin.

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

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

This functions is not available on windows and cygwin.