gcc/ada/a-direio.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --                        A D A . D I R E C T _ I O                         --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2012, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNAT was originally developed  by the GNAT team at  New York University. --
  28 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 --  This is the generic template for Direct_IO, i.e. the code that gets
  33 --  duplicated. We absolutely minimize this code by either calling routines
  34 --  in System.File_IO (for common file functions), or in System.Direct_IO
  35 --  (for specialized Direct_IO functions)
  36
  37 with Interfaces.C_Streams; use Interfaces.C_Streams;
  38 with System;               use System;
  39 with System.CRTL;
  40 with System.File_Control_Block;
  41 with System.File_IO;
  42 with System.Direct_IO;
  43 with System.Storage_Elements;
  44 with Ada.Unchecked_Conversion;
  45
  46 use type System.Direct_IO.Count;
  47
  48 package body Ada.Direct_IO is
  49
  50    Zeroes : constant System.Storage_Elements.Storage_Array :=
  51      (1 .. System.Storage_Elements.Storage_Offset (Bytes) => 0);
  52    --  Buffer used to fill out partial records
  53
  54    package FCB renames System.File_Control_Block;
  55    package FIO renames System.File_IO;
  56    package DIO renames System.Direct_IO;
  57
  58    SU : constant := System.Storage_Unit;
  59
  60    subtype AP      is FCB.AFCB_Ptr;
  61    subtype FP      is DIO.File_Type;
  62    subtype DPCount is DIO.Positive_Count;
  63
  64    function To_FCB is new Ada.Unchecked_Conversion (File_Mode, FCB.File_Mode);
  65    function To_DIO is new Ada.Unchecked_Conversion (FCB.File_Mode, File_Mode);
  66
  67    use type System.CRTL.size_t;
  68
  69    -----------
  70    -- Close --
  71    -----------
  72
  73    procedure Close (File : in out File_Type) is
  74    begin
  75       FIO.Close (AP (File)'Unrestricted_Access);
  76    end Close;
  77
  78    ------------
  79    -- Create --
  80    ------------
  81
  82    procedure Create
  83      (File : in out File_Type;
  84       Mode : File_Mode := Inout_File;
  85       Name : String := "";
  86       Form : String := "")
  87    is
  88    begin
  89       DIO.Create (FP (File), To_FCB (Mode), Name, Form);
  90       File.Bytes := Bytes;
  91    end Create;
  92
  93    ------------
  94    -- Delete --
  95    ------------
  96
  97    procedure Delete (File : in out File_Type) is
  98    begin
  99       FIO.Delete (AP (File)'Unrestricted_Access);
 100    end Delete;
 101
 102    -----------------
 103    -- End_Of_File --
 104    -----------------
 105
 106    function End_Of_File (File : File_Type) return Boolean is
 107    begin
 108       return DIO.End_Of_File (FP (File));
 109    end End_Of_File;
 110
 111    ----------
 112    -- Form --
 113    ----------
 114
 115    function Form (File : File_Type) return String is
 116    begin
 117       return FIO.Form (AP (File));
 118    end Form;
 119
 120    -----------
 121    -- Index --
 122    -----------
 123
 124    function Index (File : File_Type) return Positive_Count is
 125    begin
 126       return Positive_Count (DIO.Index (FP (File)));
 127    end Index;
 128
 129    -------------
 130    -- Is_Open --
 131    -------------
 132
 133    function Is_Open (File : File_Type) return Boolean is
 134    begin
 135       return FIO.Is_Open (AP (File));
 136    end Is_Open;
 137
 138    ----------
 139    -- Mode --
 140    ----------
 141
 142    function Mode (File : File_Type) return File_Mode is
 143    begin
 144       return To_DIO (FIO.Mode (AP (File)));
 145    end Mode;
 146
 147    ----------
 148    -- Name --
 149    ----------
 150
 151    function Name (File : File_Type) return String is
 152    begin
 153       return FIO.Name (AP (File));
 154    end Name;
 155
 156    ----------
 157    -- Open --
 158    ----------
 159
 160    procedure Open
 161      (File : in out File_Type;
 162       Mode : File_Mode;
 163       Name : String;
 164       Form : String := "")
 165    is
 166    begin
 167       DIO.Open (FP (File), To_FCB (Mode), Name, Form);
 168       File.Bytes := Bytes;
 169    end Open;
 170
 171    ----------
 172    -- Read --
 173    ----------
 174
 175    procedure Read
 176      (File : File_Type;
 177       Item : out Element_Type;
 178       From : Positive_Count)
 179    is
 180    begin
 181       --  For a non-constrained variant record type, we read into an
 182       --  intermediate buffer, since we may have the case of discriminated
 183       --  records where a discriminant check is required, and we may need
 184       --  to assign only part of the record buffer originally written.
 185
 186       --  Note: we have to turn warnings on/off because this use of
 187       --  the Constrained attribute is an obsolescent feature.
 188
 189       pragma Warnings (Off);
 190       if not Element_Type'Constrained then
 191          pragma Warnings (On);
 192
 193          declare
 194             Buf : Element_Type;
 195
 196          begin
 197             DIO.Read (FP (File), Buf'Address, Bytes, DPCount (From));
 198             Item := Buf;
 199          end;
 200
 201       --  In the normal case, we can read straight into the buffer
 202
 203       else
 204          DIO.Read (FP (File), Item'Address, Bytes, DPCount (From));
 205       end if;
 206    end Read;
 207
 208    procedure Read (File : File_Type; Item : out Element_Type) is
 209    begin
 210       --  Same processing for unconstrained case as above
 211
 212       --  Note: we have to turn warnings on/off because this use of
 213       --  the Constrained attribute is an obsolescent feature.
 214
 215       pragma Warnings (Off);
 216       if not Element_Type'Constrained then
 217          pragma Warnings (On);
 218
 219          declare
 220             Buf : Element_Type;
 221
 222          begin
 223             DIO.Read (FP (File), Buf'Address, Bytes);
 224             Item := Buf;
 225          end;
 226
 227       else
 228          DIO.Read (FP (File), Item'Address, Bytes);
 229       end if;
 230    end Read;
 231
 232    -----------
 233    -- Reset --
 234    -----------
 235
 236    procedure Reset (File : in out File_Type; Mode : File_Mode) is
 237    begin
 238       DIO.Reset (FP (File), To_FCB (Mode));
 239    end Reset;
 240
 241    procedure Reset (File : in out File_Type) is
 242    begin
 243       DIO.Reset (FP (File));
 244    end Reset;
 245
 246    ---------------
 247    -- Set_Index --
 248    ---------------
 249
 250    procedure Set_Index (File : File_Type; To : Positive_Count) is
 251    begin
 252       DIO.Set_Index (FP (File), DPCount (To));
 253    end Set_Index;
 254
 255    ----------
 256    -- Size --
 257    ----------
 258
 259    function Size (File : File_Type) return Count is
 260    begin
 261       return Count (DIO.Size (FP (File)));
 262    end Size;
 263
 264    -----------
 265    -- Write --
 266    -----------
 267
 268    procedure Write
 269      (File : File_Type;
 270       Item : Element_Type;
 271       To   : Positive_Count)
 272    is
 273    begin
 274       DIO.Set_Index (FP (File), DPCount (To));
 275       DIO.Write (FP (File), Item'Address, Item'Size / SU, Zeroes);
 276    end Write;
 277
 278    procedure Write (File : File_Type; Item : Element_Type) is
 279    begin
 280       DIO.Write (FP (File), Item'Address, Item'Size / SU, Zeroes);
 281    end Write;
 282
 283 end Ada.Direct_IO;