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------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- S Y S T E M . M M A P . O S _ I N T E R F A C E --
-- --
-- S p e c --
-- --
-- Copyright (C) 2007-2022, AdaCore --
-- --
-- This library is free software; you can redistribute it and/or modify it --
-- under terms of the GNU General Public License as published by the Free --
-- Software Foundation; either version 3, or (at your option) any later --
-- version. This library is distributed in the hope that it will be useful, --
-- but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHAN- --
-- TABILITY or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with System.OS_Lib;
-- OS pecularities abstraction package for Unix systems.
package System.Mmap.OS_Interface is
type System_File is record
Fd : System.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 :=
(System.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. Return
-- Invalid_System_File 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 System.Strings.String_Access;
-- Read a fragment of a file. It is up to the caller to free the result
-- when done with it.
procedure Write_To_Disk
(File : System_File;
Offset, Length : File_Size;
Buffer : System.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);
-- 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 boudaries, 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 System.Mmap.OS_Interface;