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) 1992-2008, 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 Ada.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 Ada.Unchecked_Conversion (File_Mode, FCB.File_Mode);
60 function To_SIO is new Ada.Unchecked_Conversion (FCB.File_Mode, File_Mode);
62 use type System.CRTL.size_t;
68 procedure Close (File : in out File_Type) is
70 for AFCB'Address use File'Address;
71 pragma Import (Ada, AFCB);
73 FIO.Close (AFCB'Access);
81 (File : in out File_Type;
82 Mode : File_Mode := Out_File;
87 SIO.Create (FP (File), To_FCB (Mode), Name, Form);
94 procedure Delete (File : in out File_Type) is
96 for AFCB'Address use File'Address;
97 pragma Import (Ada, AFCB);
99 FIO.Delete (AFCB'Access);
106 function End_Of_File (File : File_Type) return Boolean is
108 return FIO.End_Of_File (AP (File));
115 function Form (File : File_Type) return String is
117 return FIO.Form (AP (File));
124 function Is_Open (File : File_Type) return Boolean is
126 return FIO.Is_Open (AP (File));
133 function Mode (File : File_Type) return File_Mode is
135 return To_SIO (FIO.Mode (AP (File)));
142 function Name (File : File_Type) return String is
144 return FIO.Name (AP (File));
152 (File : in out File_Type;
158 SIO.Open (FP (File), To_FCB (Mode), Name, Form);
165 procedure Read (File : File_Type; Item : out Element_Type) is
166 Siz : constant size_t := (Item'Size + SU - 1) / SU;
170 FIO.Check_Read_Status (AP (File));
172 -- For non-definite type or type with discriminants, read size and
173 -- raise Program_Error if it is larger than the size of the item.
175 if not Element_Type'Definite
176 or else Element_Type'Has_Discriminants
179 (AP (File), Rsiz'Address, size_t'Size / System.Storage_Unit);
181 -- For a type with discriminants, we have to read into a temporary
182 -- buffer if Item is constrained, to check that the discriminants
185 pragma Extensions_Allowed (On);
186 -- Needed to allow Constrained reference here
188 if Element_Type'Has_Discriminants
189 and then Item'Constrained
192 RsizS : constant SSE.Storage_Offset :=
193 SSE.Storage_Offset (Rsiz - 1);
195 type SA is new SSE.Storage_Array (0 .. RsizS);
197 for SA'Alignment use Standard'Maximum_Alignment;
198 -- We will perform an unchecked conversion of a pointer-to-SA
199 -- into pointer-to-Element_Type. We need to ensure that the
200 -- source is always at least as strictly aligned as the target.
202 type SAP is access all SA;
203 type ItemP is access all Element_Type;
205 pragma Warnings (Off);
206 -- We have to turn warnings off for function To_ItemP,
207 -- because it gets analyzed for all types, including ones
208 -- which can't possibly come this way, and for which the
209 -- size of the access types differs.
211 function To_ItemP is new Ada.Unchecked_Conversion (SAP, ItemP);
213 pragma Warnings (On);
217 pragma Unsuppress (Discriminant_Check);
220 FIO.Read_Buf (AP (File), Buffer'Address, Rsiz);
221 Item := To_ItemP (Buffer'Access).all;
226 -- In the case of a non-definite type, make sure the length is OK.
227 -- We can't do this in the variant record case, because the size is
228 -- based on the current discriminant, so may be apparently wrong.
230 if not Element_Type'Has_Discriminants and then Rsiz > Siz then
234 FIO.Read_Buf (AP (File), Item'Address, Rsiz);
236 -- For definite type without discriminants, use actual size of item
239 FIO.Read_Buf (AP (File), Item'Address, Siz);
247 procedure Reset (File : in out File_Type; Mode : File_Mode) is
249 for AFCB'Address use File'Address;
250 pragma Import (Ada, AFCB);
252 FIO.Reset (AFCB'Access, To_FCB (Mode));
255 procedure Reset (File : in out File_Type) is
257 for AFCB'Address use File'Address;
258 pragma Import (Ada, AFCB);
260 FIO.Reset (AFCB'Access);
267 procedure Write (File : File_Type; Item : Element_Type) is
268 Siz : constant size_t := (Item'Size + SU - 1) / SU;
271 FIO.Check_Write_Status (AP (File));
273 -- For non-definite types or types with discriminants, write the size
275 if not Element_Type'Definite
276 or else Element_Type'Has_Discriminants
279 (AP (File), Siz'Address, size_t'Size / System.Storage_Unit);
282 FIO.Write_Buf (AP (File), Item'Address, Siz);
285 end Ada.Sequential_IO;