1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME COMPONENTS --
5 -- A D A . S E Q U E N T I A L _ I O --
9 -- Copyright (C) 1992-2006, 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, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, 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;
42 with System.File_Control_Block;
44 with System.Storage_Elements;
45 with Unchecked_Conversion;
47 package body Ada.Sequential_IO is
49 package FIO renames System.File_IO;
50 package FCB renames System.File_Control_Block;
51 package SIO renames System.Sequential_IO;
52 package SSE renames System.Storage_Elements;
54 SU : constant := System.Storage_Unit;
56 subtype AP is FCB.AFCB_Ptr;
57 subtype FP is SIO.File_Type;
59 function To_FCB is new Unchecked_Conversion (File_Mode, FCB.File_Mode);
60 function To_SIO is new Unchecked_Conversion (FCB.File_Mode, File_Mode);
62 use type System.CRTL.size_t;
68 procedure Close (File : in out File_Type) is
70 FIO.Close (AP (File));
78 (File : in out File_Type;
79 Mode : File_Mode := Out_File;
84 SIO.Create (FP (File), To_FCB (Mode), Name, Form);
91 procedure Delete (File : in out File_Type) is
93 FIO.Delete (AP (File));
100 function End_Of_File (File : File_Type) return Boolean is
102 return FIO.End_Of_File (AP (File));
109 function Form (File : File_Type) return String is
111 return FIO.Form (AP (File));
118 function Is_Open (File : File_Type) return Boolean is
120 return FIO.Is_Open (AP (File));
127 function Mode (File : File_Type) return File_Mode is
129 return To_SIO (FIO.Mode (AP (File)));
136 function Name (File : File_Type) return String is
138 return FIO.Name (AP (File));
146 (File : in out File_Type;
152 SIO.Open (FP (File), To_FCB (Mode), Name, Form);
159 procedure Read (File : File_Type; Item : out Element_Type) is
160 Siz : constant size_t := (Item'Size + SU - 1) / SU;
164 FIO.Check_Read_Status (AP (File));
166 -- For non-definite type or type with discriminants, read size and
167 -- raise Program_Error if it is larger than the size of the item.
169 if not Element_Type'Definite
170 or else Element_Type'Has_Discriminants
173 (AP (File), Rsiz'Address, size_t'Size / System.Storage_Unit);
175 -- For a type with discriminants, we have to read into a temporary
176 -- buffer if Item is constrained, to check that the discriminants
179 pragma Extensions_Allowed (On);
180 -- Needed to allow Constrained reference here
182 if Element_Type'Has_Discriminants
183 and then Item'Constrained
186 RsizS : constant SSE.Storage_Offset :=
187 SSE.Storage_Offset (Rsiz - 1);
189 type SA is new SSE.Storage_Array (0 .. RsizS);
191 for SA'Alignment use Standard'Maximum_Alignment;
192 -- We will perform an unchecked conversion of a pointer-to-SA
193 -- into pointer-to-Element_Type. We need to ensure that the
194 -- source is always at least as strictly aligned as the target.
196 type SAP is access all SA;
197 type ItemP is access all Element_Type;
199 pragma Warnings (Off);
200 -- We have to turn warnings off for function To_ItemP,
201 -- because it gets analyzed for all types, including ones
202 -- which can't possibly come this way, and for which the
203 -- size of the access types differs.
205 function To_ItemP is new Unchecked_Conversion (SAP, ItemP);
207 pragma Warnings (On);
211 pragma Unsuppress (Discriminant_Check);
214 FIO.Read_Buf (AP (File), Buffer'Address, Rsiz);
215 Item := To_ItemP (Buffer'Access).all;
220 -- In the case of a non-definite type, make sure the length is OK.
221 -- We can't do this in the variant record case, because the size is
222 -- based on the current discriminant, so may be apparently wrong.
224 if not Element_Type'Has_Discriminants and then Rsiz > Siz then
228 FIO.Read_Buf (AP (File), Item'Address, Rsiz);
230 -- For definite type without discriminants, use actual size of item
233 FIO.Read_Buf (AP (File), Item'Address, Siz);
241 procedure Reset (File : in out File_Type; Mode : File_Mode) is
243 FIO.Reset (AP (File), To_FCB (Mode));
246 procedure Reset (File : in out File_Type) is
248 FIO.Reset (AP (File));
255 procedure Write (File : File_Type; Item : Element_Type) is
256 Siz : constant size_t := (Item'Size + SU - 1) / SU;
259 FIO.Check_Write_Status (AP (File));
261 -- For non-definite types or types with discriminants, write the size
263 if not Element_Type'Definite
264 or else Element_Type'Has_Discriminants
267 (AP (File), Siz'Address, size_t'Size / System.Storage_Unit);
270 FIO.Write_Buf (AP (File), Item'Address, Siz);
273 end Ada.Sequential_IO;