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) 1992-2018, 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.Storage_Elements;
43with Ada.Unchecked_Conversion;
44
45package body Ada.Direct_IO is
46
47   Zeroes : constant System.Storage_Elements.Storage_Array :=
48     (1 .. System.Storage_Elements.Storage_Offset (Bytes) => 0);
49   --  Buffer used to fill out partial records
50
51   package FCB renames System.File_Control_Block;
52   package FIO renames System.File_IO;
53   package DIO renames System.Direct_IO;
54
55   SU : constant := System.Storage_Unit;
56
57   subtype AP      is FCB.AFCB_Ptr;
58   subtype FP      is DIO.File_Type;
59   subtype DPCount is DIO.Positive_Count;
60
61   function To_FCB is new Ada.Unchecked_Conversion (File_Mode, FCB.File_Mode);
62   function To_DIO is new Ada.Unchecked_Conversion (FCB.File_Mode, File_Mode);
63
64   use type System.CRTL.size_t;
65
66   -----------
67   -- Close --
68   -----------
69
70   procedure Close (File : in out File_Type) is
71   begin
72      FIO.Close (AP (File)'Unrestricted_Access);
73   end Close;
74
75   ------------
76   -- Create --
77   ------------
78
79   procedure Create
80     (File : in out File_Type;
81      Mode : File_Mode := Inout_File;
82      Name : String := "";
83      Form : String := "")
84   is
85   begin
86      DIO.Create (FP (File), To_FCB (Mode), Name, Form);
87      File.Bytes := Bytes;
88   end Create;
89
90   ------------
91   -- Delete --
92   ------------
93
94   procedure Delete (File : in out File_Type) is
95   begin
96      FIO.Delete (AP (File)'Unrestricted_Access);
97   end Delete;
98
99   -----------------
100   -- End_Of_File --
101   -----------------
102
103   function End_Of_File (File : File_Type) return Boolean is
104   begin
105      return DIO.End_Of_File (FP (File));
106   end End_Of_File;
107
108   -----------
109   -- Flush --
110   -----------
111
112   procedure Flush (File : File_Type) is
113   begin
114      FIO.Flush (AP (File));
115   end Flush;
116
117   ----------
118   -- Form --
119   ----------
120
121   function Form (File : File_Type) return String is
122   begin
123      return FIO.Form (AP (File));
124   end Form;
125
126   -----------
127   -- Index --
128   -----------
129
130   function Index (File : File_Type) return Positive_Count is
131   begin
132      return Positive_Count (DIO.Index (FP (File)));
133   end Index;
134
135   -------------
136   -- Is_Open --
137   -------------
138
139   function Is_Open (File : File_Type) return Boolean is
140   begin
141      return FIO.Is_Open (AP (File));
142   end Is_Open;
143
144   ----------
145   -- Mode --
146   ----------
147
148   function Mode (File : File_Type) return File_Mode is
149   begin
150      return To_DIO (FIO.Mode (AP (File)));
151   end Mode;
152
153   ----------
154   -- Name --
155   ----------
156
157   function Name (File : File_Type) return String is
158   begin
159      return FIO.Name (AP (File));
160   end Name;
161
162   ----------
163   -- Open --
164   ----------
165
166   procedure Open
167     (File : in out File_Type;
168      Mode : File_Mode;
169      Name : String;
170      Form : String := "")
171   is
172   begin
173      DIO.Open (FP (File), To_FCB (Mode), Name, Form);
174      File.Bytes := Bytes;
175   end Open;
176
177   ----------
178   -- Read --
179   ----------
180
181   procedure Read
182     (File : File_Type;
183      Item : out Element_Type;
184      From : Positive_Count)
185   is
186   begin
187      --  For a non-constrained variant record type, we read into an
188      --  intermediate buffer, since we may have the case of discriminated
189      --  records where a discriminant check is required, and we may need
190      --  to assign only part of the record buffer originally written.
191
192      --  Note: we have to turn warnings on/off because this use of
193      --  the Constrained attribute is an obsolescent feature.
194
195      pragma Warnings (Off);
196      if not Element_Type'Constrained then
197         pragma Warnings (On);
198
199         declare
200            Buf : Element_Type;
201
202         begin
203            DIO.Read (FP (File), Buf'Address, Bytes, DPCount (From));
204            Item := Buf;
205         end;
206
207      --  In the normal case, we can read straight into the buffer
208
209      else
210         DIO.Read (FP (File), Item'Address, Bytes, DPCount (From));
211      end if;
212   end Read;
213
214   procedure Read (File : File_Type; Item : out Element_Type) is
215   begin
216      --  Same processing for unconstrained case as above
217
218      --  Note: we have to turn warnings on/off because this use of
219      --  the Constrained attribute is an obsolescent feature.
220
221      pragma Warnings (Off);
222      if not Element_Type'Constrained then
223         pragma Warnings (On);
224
225         declare
226            Buf : Element_Type;
227
228         begin
229            DIO.Read (FP (File), Buf'Address, Bytes);
230            Item := Buf;
231         end;
232
233      else
234         DIO.Read (FP (File), Item'Address, Bytes);
235      end if;
236   end Read;
237
238   -----------
239   -- Reset --
240   -----------
241
242   procedure Reset (File : in out File_Type; Mode : File_Mode) is
243   begin
244      DIO.Reset (FP (File), To_FCB (Mode));
245   end Reset;
246
247   procedure Reset (File : in out File_Type) is
248   begin
249      DIO.Reset (FP (File));
250   end Reset;
251
252   ---------------
253   -- Set_Index --
254   ---------------
255
256   procedure Set_Index (File : File_Type; To : Positive_Count) is
257   begin
258      DIO.Set_Index (FP (File), DPCount (To));
259   end Set_Index;
260
261   ----------
262   -- Size --
263   ----------
264
265   function Size (File : File_Type) return Count is
266   begin
267      return Count (DIO.Size (FP (File)));
268   end Size;
269
270   -----------
271   -- Write --
272   -----------
273
274   procedure Write
275     (File : File_Type;
276      Item : Element_Type;
277      To   : Positive_Count)
278   is
279   begin
280      DIO.Set_Index (FP (File), DPCount (To));
281      DIO.Write (FP (File), Item'Address, Item'Size / SU, Zeroes);
282   end Write;
283
284   procedure Write (File : File_Type; Item : Element_Type) is
285   begin
286      DIO.Write (FP (File), Item'Address, Item'Size / SU, Zeroes);
287   end Write;
288
289end Ada.Direct_IO;
290