Module Mmap

module Mmap: sig .. end

Accessing memory-mapped files as strings.

This module allows one to map files into memory and access them byte by byte, or by extracing or blitting substrings.

type t

A type representing a memory-mapped file

val map : ?write:bool ->
       ?copy:bool -> ?offset:int64 -> ?length:int64 -> Unix.file_descr -> t

map fd copy offset length maps the bytes offset .. offset + length - 1 of file fd; if copy is true, the file is mapped in copy-on-write mode.

val unmap : t -> unit

unmap mp removes the mapping mp ; all subsequent calls with mp will raise an Invalid_argument exception.

val sub : t -> int64 -> int -> string

sub mp o n copies the bytes from offset + o to offset + o + n into a new string

val length : t -> int64

Returns the length of the mapped region

val offset : t -> int64

Returns the offset of the mapped region

val blit : t -> int64 -> string -> int -> int -> unit

blit mp i u j n copies the bytes j to j + n - 1 of the string u into the bytes offset + i to offset + i + n - 1 of the map.

val paste : t -> int64 -> string -> unit

paste mp i u copies the string u into the bytes offset + i to offset + i + n - 1 of the map, where n is the length of the string u.