1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT RUNTIME COMPONENTS                          --
4--                                                                          --
5--                        A D A . D I R E C T _ I O                         --
6--                                                                          --
7--                                 B o d y                                  --
8--                                                                          --
9--          Copyright (C) 1992-2003 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 2,  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.  See the GNU General Public License --
17-- for  more details.  You should have  received  a copy of the GNU General --
18-- Public License  distributed with GNAT;  see file COPYING.  If not, write --
19-- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
20-- MA 02111-1307, USA.                                                      --
21--                                                                          --
22-- As a special exception,  if other files  instantiate  generics from this --
23-- unit, or you link  this unit with other files  to produce an executable, --
24-- this  unit  does not  by itself cause  the resulting  executable  to  be --
25-- covered  by the  GNU  General  Public  License.  This exception does not --
26-- however invalidate  any other reasons why  the executable file  might be --
27-- covered by the  GNU Public License.                                      --
28--                                                                          --
29-- GNAT was originally developed  by the GNAT team at  New York University. --
30-- Extensive contributions were provided by Ada Core Technologies Inc.      --
31--                                                                          --
32------------------------------------------------------------------------------
33
34--  This is the generic template for Direct_IO, i.e. the code that gets
35--  duplicated. We absolutely minimize this code by either calling routines
36--  in System.File_IO (for common file functions), or in System.Direct_IO
37--  (for specialized Direct_IO functions)
38
39with Interfaces.C_Streams; use Interfaces.C_Streams;
40with System;               use System;
41with System.CRTL;
42with System.File_Control_Block;
43with System.File_IO;
44with System.Direct_IO;
45with System.Storage_Elements;
46with Unchecked_Conversion;
47
48use type System.Direct_IO.Count;
49
50package body Ada.Direct_IO is
51
52   Zeroes : constant System.Storage_Elements.Storage_Array :=
53              (1 .. System.Storage_Elements.Storage_Offset (Bytes) => 0);
54   --  Buffer used to fill out partial records.
55
56   package FCB renames System.File_Control_Block;
57   package FIO renames System.File_IO;
58   package DIO renames System.Direct_IO;
59
60   SU : constant := System.Storage_Unit;
61
62   subtype AP      is FCB.AFCB_Ptr;
63   subtype FP      is DIO.File_Type;
64   subtype DPCount is DIO.Positive_Count;
65
66   function To_FCB is new Unchecked_Conversion (File_Mode, FCB.File_Mode);
67   function To_DIO is new Unchecked_Conversion (FCB.File_Mode, File_Mode);
68
69   use type System.CRTL.size_t;
70
71   -----------
72   -- Close --
73   -----------
74
75   procedure Close (File : in out File_Type) is
76   begin
77      FIO.Close (AP (File));
78   end Close;
79
80   ------------
81   -- Create --
82   ------------
83
84   procedure Create
85     (File : in out File_Type;
86      Mode : in File_Mode := Inout_File;
87      Name : in String := "";
88      Form : in String := "")
89   is
90   begin
91      DIO.Create (FP (File), To_FCB (Mode), Name, Form);
92      File.Bytes := Bytes;
93   end Create;
94
95   ------------
96   -- Delete --
97   ------------
98
99   procedure Delete (File : in out File_Type) is
100   begin
101      FIO.Delete (AP (File));
102   end Delete;
103
104   -----------------
105   -- End_Of_File --
106   -----------------
107
108   function End_Of_File (File : in File_Type) return Boolean is
109   begin
110      return DIO.End_Of_File (FP (File));
111   end End_Of_File;
112
113   ----------
114   -- Form --
115   ----------
116
117   function Form (File : in File_Type) return String is
118   begin
119      return FIO.Form (AP (File));
120   end Form;
121
122   -----------
123   -- Index --
124   -----------
125
126   function Index (File : in File_Type) return Positive_Count is
127   begin
128      return Positive_Count (DIO.Index (FP (File)));
129   end Index;
130
131   -------------
132   -- Is_Open --
133   -------------
134
135   function Is_Open (File : in File_Type) return Boolean is
136   begin
137      return FIO.Is_Open (AP (File));
138   end Is_Open;
139
140   ----------
141   -- Mode --
142   ----------
143
144   function Mode (File : in File_Type) return File_Mode is
145   begin
146      return To_DIO (FIO.Mode (AP (File)));
147   end Mode;
148
149   ----------
150   -- Name --
151   ----------
152
153   function Name (File : in File_Type) return String is
154   begin
155      return FIO.Name (AP (File));
156   end Name;
157
158   ----------
159   -- Open --
160   ----------
161
162   procedure Open
163     (File : in out File_Type;
164      Mode : in File_Mode;
165      Name : in String;
166      Form : in String := "")
167   is
168   begin
169      DIO.Open (FP (File), To_FCB (Mode), Name, Form);
170      File.Bytes := Bytes;
171   end Open;
172
173   ----------
174   -- Read --
175   ----------
176
177   procedure Read
178     (File : in File_Type;
179      Item : out Element_Type;
180      From : in Positive_Count)
181   is
182   begin
183      --  For a non-constrained variant record type, we read into an
184      --  intermediate buffer, since we may have the case of discriminated
185      --  records where a discriminant check is required, and we may need
186      --  to assign only part of the record buffer originally written
187
188      if not Element_Type'Constrained then
189         declare
190            Buf : Element_Type;
191
192         begin
193            DIO.Read (FP (File), Buf'Address, Bytes, DPCount (From));
194            Item := Buf;
195         end;
196
197      --  In the normal case, we can read straight into the buffer
198
199      else
200         DIO.Read (FP (File), Item'Address, Bytes, DPCount (From));
201      end if;
202   end Read;
203
204   procedure Read (File : in File_Type; Item : out Element_Type) is
205   begin
206      --  Same processing for unconstrained case as above
207
208      if not Element_Type'Constrained then
209         declare
210            Buf : Element_Type;
211
212         begin
213            DIO.Read (FP (File), Buf'Address, Bytes);
214            Item := Buf;
215         end;
216
217      else
218         DIO.Read (FP (File), Item'Address, Bytes);
219      end if;
220   end Read;
221
222   -----------
223   -- Reset --
224   -----------
225
226   procedure Reset (File : in out File_Type; Mode : in File_Mode) is
227   begin
228      DIO.Reset (FP (File), To_FCB (Mode));
229   end Reset;
230
231   procedure Reset (File : in out File_Type) is
232   begin
233      DIO.Reset (FP (File));
234   end Reset;
235
236   ---------------
237   -- Set_Index --
238   ---------------
239
240   procedure Set_Index (File : in File_Type; To : in Positive_Count) is
241   begin
242      DIO.Set_Index (FP (File), DPCount (To));
243   end Set_Index;
244
245   ----------
246   -- Size --
247   ----------
248
249   function Size (File : in File_Type) return Count is
250   begin
251      return Count (DIO.Size (FP (File)));
252   end Size;
253
254   -----------
255   -- Write --
256   -----------
257
258   procedure Write
259     (File : in File_Type;
260      Item : in Element_Type;
261      To   : in Positive_Count)
262   is
263   begin
264      DIO.Set_Index (FP (File), DPCount (To));
265      DIO.Write (FP (File), Item'Address, Item'Size / SU, Zeroes);
266   end Write;
267
268   procedure Write (File : in File_Type; Item : in Element_Type) is
269   begin
270      DIO.Write (FP (File), Item'Address, Item'Size / SU, Zeroes);
271   end Write;
272
273end Ada.Direct_IO;
274