gcc/ada/6vcstrea.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                 I N T E R F A C E S . C _ S T R E A M S                  --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1996-2002 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 Alpha/VMS version.
  35
  36 with Unchecked_Conversion;
  37 package body Interfaces.C_Streams is
  38
  39    ------------
  40    -- fread --
  41    ------------
  42
  43    function fread
  44      (buffer : voids;
  45       size   : size_t;
  46       count  : size_t;
  47       stream : FILEs)
  48       return   size_t
  49    is
  50       Get_Count : size_t := 0;
  51       type Buffer_Type is array (size_t range 1 .. count,
  52                                  size_t range 1 .. size) of Character;
  53       type Buffer_Access is access Buffer_Type;
  54       function To_BA is new Unchecked_Conversion (voids, Buffer_Access);
  55       BA : Buffer_Access := To_BA (buffer);
  56       Ch : int;
  57    begin
  58
  59       --  This Fread goes with the Fwrite below.
  60       --  The C library fread sometimes can't read fputc generated files.
  61
  62       for C in 1 .. count loop
  63          for S in 1 .. size loop
  64             Ch := fgetc (stream);
  65             if Ch = EOF then
  66                return 0;
  67             end if;
  68             BA.all (C, S) := Character'Val (Ch);
  69          end loop;
  70          Get_Count := Get_Count + 1;
  71       end loop;
  72       return Get_Count;
  73    end fread;
  74
  75    ------------
  76    -- fread --
  77    ------------
  78
  79    function fread
  80      (buffer : voids;
  81       index  : size_t;
  82       size   : size_t;
  83       count  : size_t;
  84       stream : FILEs)
  85       return   size_t
  86    is
  87       Get_Count : size_t := 0;
  88       type Buffer_Type is array (size_t range 1 .. count,
  89                                  size_t range 1 .. size) of Character;
  90       type Buffer_Access is access Buffer_Type;
  91       function To_BA is new Unchecked_Conversion (voids, Buffer_Access);
  92       BA : Buffer_Access := To_BA (buffer);
  93       Ch : int;
  94    begin
  95
  96       --  This Fread goes with the Fwrite below.
  97       --  The C library fread sometimes can't read fputc generated files.
  98
  99       for C in 1 + index .. count + index loop
 100          for S in 1 .. size loop
 101             Ch := fgetc (stream);
 102             if Ch = EOF then
 103                return 0;
 104             end if;
 105             BA.all (C, S) := Character'Val (Ch);
 106          end loop;
 107          Get_Count := Get_Count + 1;
 108       end loop;
 109       return Get_Count;
 110    end fread;
 111
 112    ------------
 113    -- fwrite --
 114    ------------
 115
 116    function fwrite
 117      (buffer : voids;
 118       size   : size_t;
 119       count  : size_t;
 120       stream : FILEs)
 121       return   size_t
 122    is
 123       Put_Count : size_t := 0;
 124       type Buffer_Type is array (size_t range 1 .. count,
 125                                  size_t range 1 .. size) of Character;
 126       type Buffer_Access is access Buffer_Type;
 127       function To_BA is new Unchecked_Conversion (voids, Buffer_Access);
 128       BA : Buffer_Access := To_BA (buffer);
 129    begin
 130
 131       --  Fwrite on VMS has the undesirable effect of always generating at
 132       --  least one record of output per call, regardless of buffering.  To
 133       --  get around this, we do multiple fputc calls instead.
 134
 135       for C in 1 .. count loop
 136          for S in 1 .. size loop
 137             if fputc (Character'Pos (BA.all (C, S)), stream) = EOF then
 138                exit;
 139             end if;
 140          end loop;
 141          Put_Count := Put_Count + 1;
 142       end loop;
 143       return Put_Count;
 144    end fwrite;
 145
 146    -------------
 147    -- setvbuf --
 148    -------------
 149
 150    function setvbuf
 151      (stream : FILEs;
 152       buffer : chars;
 153       mode   : int;
 154       size   : size_t)
 155       return   int
 156    is
 157       function C_setvbuf
 158         (stream : FILEs;
 159          buffer : chars;
 160          mode   : int;
 161          size   : size_t)
 162          return   int;
 163       pragma Import (C, C_setvbuf, "setvbuf");
 164
 165       use type System.Address;
 166    begin
 167
 168       --  In order for the above fwrite hack to work, we must always buffer
 169       --  stdout and stderr. Is_regular_file on VMS cannot detect when
 170       --  these are redirected to a file, so checking for that condition
 171       --  doesn't help.
 172
 173       if mode = IONBF
 174         and then (stream = stdout or else stream = stderr)
 175       then
 176          return C_setvbuf (stream, buffer, IOLBF, size);
 177       else
 178          return C_setvbuf (stream, buffer, mode, size);
 179       end if;
 180    end setvbuf;
 181
 182 end Interfaces.C_Streams;