package GNATCOLL.Mmap.System is
type System_File is record
Fd : GNAT.OS_Lib.File_Descriptor;
Mapped : Boolean;
-- Whether mapping is requested by the user and available on the system
Write : Boolean;
-- Whether this file can be written to
Length : File_Size;
-- Length of the file. Used to know what can be mapped in the file
end record;
type System_Mapping is record
Address : Standard.System.Address;
Length : File_Size;
end record;
Invalid_System_File : constant System_File :=
(GNAT.OS_Lib.Invalid_FD, False, False, 0);
Invalid_System_Mapping : constant System_Mapping :=
(Standard.System.Null_Address, 0);
function Open_Read
(Filename : String;
Use_Mmap_If_Available : Boolean := True) return System_File;
-- Open a file for reading and return the corresponding System_File. Raise
-- a Ada.IO_Exceptions.Name_Error if unsuccessful.
function Open_Write
(Filename : String;
Use_Mmap_If_Available : Boolean := True) return System_File;
-- Likewise for writing to a file
procedure Close (File : in out System_File);
-- Close a system file
function Read_From_Disk
(File : System_File;
Offset, Length : File_Size) return GNAT.Strings.String_Access;
-- Read a fragment of a file. It is up to the caller to free the result
-- when done with it.
-- Doesn't use mmap.
procedure Write_To_Disk
(File : System_File;
Offset, Length : File_Size;
Buffer : GNAT.Strings.String_Access);
-- Write some content to a fragment of a file
procedure Create_Mapping
(File : System_File;
Offset, Length : in out File_Size;
Mutable : Boolean;
Mapping : out System_Mapping;
Advice : Use_Advice := Use_Normal);
-- Create a memory mapping for the given File, for the area starting at
-- Offset and containing Length bytes. Store it to Mapping.
-- Note that Offset and Length may be modified according to the system
-- needs (for boundaries, for instance). The caller must cope with actually
-- wider mapped areas.
procedure Dispose_Mapping
(Mapping : in out System_Mapping);
-- Unmap a previously-created mapping
function Get_Page_Size return File_Size;
-- Return the number of bytes in a system page.
end GNATCOLL.Mmap.System;