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
37with Interfaces.C_Streams; use Interfaces.C_Streams;
38with System;               use System;
39with System.CRTL;
40with System.File_Control_Block;
41with System.File_IO;
42with System.Direct_IO;
43with System.Storage_Elements;
44with Ada.Unchecked_Conversion;
45
46use type System.Direct_IO.Count;
47
48package 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
283end Ada.Direct_IO;
284