1 ------------------------------------------------------------------------------
3 -- GNAT RUNTIME COMPONENTS --
5 -- A D A . S E Q U E N T I A L _ I O --
9 -- Copyright (C) 1992-2002, Free Software Foundation, Inc. --
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. --
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. --
29 -- GNAT was originally developed by the GNAT team at New York University. --
30 -- Extensive contributions were provided by Ada Core Technologies Inc. --
32 ------------------------------------------------------------------------------
34 -- This is the generic template for Sequential_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.Sequential_IO
37 -- (for specialized Sequential_IO functions)
39 with Interfaces.C_Streams; use Interfaces.C_Streams;
41 with System.File_Control_Block;
43 with System.Storage_Elements;
44 with Unchecked_Conversion;
46 package body Ada.Sequential_IO is
48 package FIO renames System.File_IO;
49 package FCB renames System.File_Control_Block;
50 package SIO renames System.Sequential_IO;
51 package SSE renames System.Storage_Elements;
53 SU : constant := System.Storage_Unit;
55 subtype AP is FCB.AFCB_Ptr;
56 subtype FP is SIO.File_Type;
58 function To_FCB is new Unchecked_Conversion (File_Mode, FCB.File_Mode);
59 function To_SIO is new Unchecked_Conversion (FCB.File_Mode, File_Mode);
65 procedure Close (File : in out File_Type) is
67 FIO.Close (AP (File));
75 (File : in out File_Type;
76 Mode : in File_Mode := Out_File;
77 Name : in String := "";
78 Form : in String := "")
81 SIO.Create (FP (File), To_FCB (Mode), Name, Form);
88 procedure Delete (File : in out File_Type) is
90 FIO.Delete (AP (File));
97 function End_Of_File (File : in File_Type) return Boolean is
99 return FIO.End_Of_File (AP (File));
106 function Form (File : in File_Type) return String is
108 return FIO.Form (AP (File));
115 function Is_Open (File : in File_Type) return Boolean is
117 return FIO.Is_Open (AP (File));
124 function Mode (File : in File_Type) return File_Mode is
126 return To_SIO (FIO.Mode (AP (File)));
133 function Name (File : in File_Type) return String is
135 return FIO.Name (AP (File));
143 (File : in out File_Type;
146 Form : in String := "")
149 SIO.Open (FP (File), To_FCB (Mode), Name, Form);
156 procedure Read (File : in File_Type; Item : out Element_Type) is
157 Siz : constant size_t := (Item'Size + SU - 1) / SU;
161 FIO.Check_Read_Status (AP (File));
163 -- For non-definite type or type with discriminants, read size and
164 -- raise Program_Error if it is larger than the size of the item.
166 if not Element_Type'Definite
167 or else Element_Type'Has_Discriminants
170 (AP (File), Rsiz'Address, size_t'Size / System.Storage_Unit);
172 -- For a type with discriminants, we have to read into a temporary
173 -- buffer if Item is constrained, to check that the discriminants
176 pragma Extensions_Allowed (On);
177 -- Needed to allow Constrained reference here
179 if Element_Type'Has_Discriminants
180 and then Item'Constrained
183 RsizS : constant SSE.Storage_Offset :=
184 SSE.Storage_Offset (Rsiz - 1);
186 type SA is new SSE.Storage_Array (0 .. RsizS);
188 for SA'Alignment use Standard'Maximum_Alignment;
189 -- We will perform an unchecked conversion of a pointer-to-SA
190 -- into pointer-to-Element_Type. We need to ensure that the
191 -- source is always at least as strictly aligned as the target.
193 type SAP is access all SA;
194 type ItemP is access all Element_Type;
196 pragma Warnings (Off);
197 -- We have to turn warnings off for function To_ItemP,
198 -- because it gets analyzed for all types, including ones
199 -- which can't possibly come this way, and for which the
200 -- size of the access types differs.
202 function To_ItemP is new Unchecked_Conversion (SAP, ItemP);
204 pragma Warnings (On);
208 pragma Unsuppress (Discriminant_Check);
211 FIO.Read_Buf (AP (File), Buffer'Address, Rsiz);
212 Item := To_ItemP (Buffer'Access).all;
217 -- In the case of a non-definite type, make sure the length is OK.
218 -- We can't do this in the variant record case, because the size is
219 -- based on the current discriminant, so may be apparently wrong.
221 if not Element_Type'Has_Discriminants and then Rsiz > Siz then
225 FIO.Read_Buf (AP (File), Item'Address, Rsiz);
227 -- For definite type without discriminants, use actual size of item
230 FIO.Read_Buf (AP (File), Item'Address, Siz);
238 procedure Reset (File : in out File_Type; Mode : in File_Mode) is
240 FIO.Reset (AP (File), To_FCB (Mode));
243 procedure Reset (File : in out File_Type) is
245 FIO.Reset (AP (File));
252 procedure Write (File : in File_Type; Item : in Element_Type) is
253 Siz : constant size_t := (Item'Size + SU - 1) / SU;
256 FIO.Check_Write_Status (AP (File));
258 -- For non-definite types or types with discriminants, write the size
260 if not Element_Type'Definite
261 or else Element_Type'Has_Discriminants
264 (AP (File), Siz'Address, size_t'Size / System.Storage_Unit);
267 FIO.Write_Buf (AP (File), Item'Address, Siz);
270 end Ada.Sequential_IO;