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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT RUN-TIME COMPONENTS --
4 -- --
5 -- A D A . S E Q U E N T I A L _ I O --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2013, 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 ------------------------------------------------------------------------------
32 -- This is the generic template for Sequential_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.Sequential_IO
35 -- (for specialized Sequential_IO functions)
37 with Ada.Unchecked_Conversion;
39 with System;
40 with System.Byte_Swapping;
41 with System.CRTL;
42 with System.File_Control_Block;
43 with System.File_IO;
44 with System.Storage_Elements;
46 with Interfaces.C_Streams; use Interfaces.C_Streams;
48 package body Ada.Sequential_IO is
50 package FIO renames System.File_IO;
51 package FCB renames System.File_Control_Block;
52 package SIO renames System.Sequential_IO;
53 package SSE renames System.Storage_Elements;
55 SU : constant := System.Storage_Unit;
57 subtype AP is FCB.AFCB_Ptr;
58 subtype FP is SIO.File_Type;
60 function To_FCB is new Ada.Unchecked_Conversion (File_Mode, FCB.File_Mode);
61 function To_SIO is new Ada.Unchecked_Conversion (FCB.File_Mode, File_Mode);
63 use type System.Bit_Order;
64 use type System.CRTL.size_t;
66 procedure Byte_Swap (Siz : in out size_t);
67 -- Byte swap Siz
69 ---------------
70 -- Byte_Swap --
71 ---------------
73 procedure Byte_Swap (Siz : in out size_t) is
74 use System.Byte_Swapping;
75 begin
76 case Siz'Size is
77 when 32 => Siz := size_t (Bswap_32 (U32 (Siz)));
78 when 64 => Siz := size_t (Bswap_64 (U64 (Siz)));
79 when others => raise Program_Error;
80 end case;
81 end Byte_Swap;
83 -----------
84 -- Close --
85 -----------
87 procedure Close (File : in out File_Type) is
88 begin
89 FIO.Close (AP (File)'Unrestricted_Access);
90 end Close;
92 ------------
93 -- Create --
94 ------------
96 procedure Create
97 (File : in out File_Type;
98 Mode : File_Mode := Out_File;
99 Name : String := "";
100 Form : String := "")
102 begin
103 SIO.Create (FP (File), To_FCB (Mode), Name, Form);
104 end Create;
106 ------------
107 -- Delete --
108 ------------
110 procedure Delete (File : in out File_Type) is
111 begin
112 FIO.Delete (AP (File)'Unrestricted_Access);
113 end Delete;
115 -----------------
116 -- End_Of_File --
117 -----------------
119 function End_Of_File (File : File_Type) return Boolean is
120 begin
121 return FIO.End_Of_File (AP (File));
122 end End_Of_File;
124 ----------
125 -- Form --
126 ----------
128 function Form (File : File_Type) return String is
129 begin
130 return FIO.Form (AP (File));
131 end Form;
133 -------------
134 -- Is_Open --
135 -------------
137 function Is_Open (File : File_Type) return Boolean is
138 begin
139 return FIO.Is_Open (AP (File));
140 end Is_Open;
142 ----------
143 -- Mode --
144 ----------
146 function Mode (File : File_Type) return File_Mode is
147 begin
148 return To_SIO (FIO.Mode (AP (File)));
149 end Mode;
151 ----------
152 -- Name --
153 ----------
155 function Name (File : File_Type) return String is
156 begin
157 return FIO.Name (AP (File));
158 end Name;
160 ----------
161 -- Open --
162 ----------
164 procedure Open
165 (File : in out File_Type;
166 Mode : File_Mode;
167 Name : String;
168 Form : String := "")
170 begin
171 SIO.Open (FP (File), To_FCB (Mode), Name, Form);
172 end Open;
174 ----------
175 -- Read --
176 ----------
178 procedure Read (File : File_Type; Item : out Element_Type) is
179 Siz : constant size_t := (Item'Size + SU - 1) / SU;
180 Rsiz : size_t;
182 begin
183 FIO.Check_Read_Status (AP (File));
185 -- For non-definite type or type with discriminants, read size and
186 -- raise Program_Error if it is larger than the size of the item.
188 if not Element_Type'Definite
189 or else Element_Type'Has_Discriminants
190 then
191 FIO.Read_Buf
192 (AP (File), Rsiz'Address, size_t'Size / System.Storage_Unit);
194 -- If item read has non-default scalar storage order, then the size
195 -- will have been written with that same order, so byte swap it.
197 if Element_Type'Scalar_Storage_Order /= System.Default_Bit_Order then
198 Byte_Swap (Rsiz);
199 end if;
201 -- For a type with discriminants, we have to read into a temporary
202 -- buffer if Item is constrained, to check that the discriminants
203 -- are correct.
205 if Element_Type'Has_Discriminants and then Item'Constrained then
206 declare
207 RsizS : constant SSE.Storage_Offset :=
208 SSE.Storage_Offset (Rsiz - 1);
210 type SA is new SSE.Storage_Array (0 .. RsizS);
212 for SA'Alignment use Standard'Maximum_Alignment;
213 -- We will perform an unchecked conversion of a pointer-to-SA
214 -- into pointer-to-Element_Type. We need to ensure that the
215 -- source is always at least as strictly aligned as the target.
217 type SAP is access all SA;
218 type ItemP is access all Element_Type;
220 pragma Warnings (Off);
221 -- We have to turn warnings off for function To_ItemP,
222 -- because it gets analyzed for all types, including ones
223 -- which can't possibly come this way, and for which the
224 -- size of the access types differs.
226 function To_ItemP is new Ada.Unchecked_Conversion (SAP, ItemP);
228 pragma Warnings (On);
230 Buffer : aliased SA;
232 pragma Unsuppress (Discriminant_Check);
234 begin
235 FIO.Read_Buf (AP (File), Buffer'Address, Rsiz);
236 Item := To_ItemP (Buffer'Access).all;
237 return;
238 end;
239 end if;
241 -- In the case of a non-definite type, make sure the length is OK.
242 -- We can't do this in the variant record case, because the size is
243 -- based on the current discriminant, so may be apparently wrong.
245 if not Element_Type'Has_Discriminants and then Rsiz > Siz then
246 raise Program_Error;
247 end if;
249 FIO.Read_Buf (AP (File), Item'Address, Rsiz);
251 -- For definite type without discriminants, use actual size of item
253 else
254 FIO.Read_Buf (AP (File), Item'Address, Siz);
255 end if;
256 end Read;
258 -----------
259 -- Reset --
260 -----------
262 procedure Reset (File : in out File_Type; Mode : File_Mode) is
263 begin
264 FIO.Reset (AP (File)'Unrestricted_Access, To_FCB (Mode));
265 end Reset;
267 procedure Reset (File : in out File_Type) is
268 begin
269 FIO.Reset (AP (File)'Unrestricted_Access);
270 end Reset;
272 -----------
273 -- Write --
274 -----------
276 procedure Write (File : File_Type; Item : Element_Type) is
277 Siz : constant size_t := (Item'Size + SU - 1) / SU;
278 -- Size to be written, in native representation
280 Swapped_Siz : size_t := Siz;
281 -- Same, possibly byte swapped to account for Element_Type endianness
283 begin
284 FIO.Check_Write_Status (AP (File));
286 -- For non-definite types or types with discriminants, write the size
288 if not Element_Type'Definite
289 or else Element_Type'Has_Discriminants
290 then
291 -- If item written has non-default scalar storage order, then the
292 -- size is written with that same order, so byte swap it.
294 if Element_Type'Scalar_Storage_Order /= System.Default_Bit_Order then
295 Byte_Swap (Swapped_Siz);
296 end if;
298 FIO.Write_Buf
299 (AP (File), Swapped_Siz'Address, size_t'Size / System.Storage_Unit);
300 end if;
302 FIO.Write_Buf (AP (File), Item'Address, Siz);
303 end Write;
305 end Ada.Sequential_IO;