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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                               O U T P U T                                --

--                                                                          --

--                                 S p e c                                  --

--                                                                          --

--          Copyright (C) 1992-2009, Free Software Foundation, Inc.         --

--                                                                          --

-- GNAT is free software;  you can  redistribute it  and/or modify it under --

-- terms of the  GNU General Public License as published  by the Free Soft- --

-- ware  Foundation;  either version 3,  or (at your option) any later ver- --

-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --

-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --

-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --

--                                                                          --

-- As a special exception under Section 7 of GPL version 3, you are granted --

-- additional permissions described in the GCC Runtime Library Exception,   --

-- version 3.1, as published by the Free Software Foundation.               --

--                                                                          --

-- You should have received a copy of the GNU General Public License and    --

-- a copy of the GCC Runtime Library Exception along with this program;     --

-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --

-- <http://www.gnu.org/licenses/>.                                          --

--                                                                          --

-- GNAT was originally developed  by the GNAT team at  New York University. --

-- Extensive contributions were provided by Ada Core Technologies Inc.      --

--                                                                          --

------------------------------------------------------------------------------

--  This package contains low level output routines used by the compiler

--  for writing error messages and informational output. It is also used

--  by the debug source file output routines (see Sprintf.Print_Eol).

with Hostparm; use Hostparm;

with Types;    use Types;

package Output is

   pragma Elaborate_Body;

   type Output_Proc is access procedure (S : String);

   --  This type is used for the Set_Special_Output procedure. If this

   --  procedure is called, then instead of lines being written to

   --  standard error or standard output, a call is made to the given

   --  procedure for each line, passing the line with an end of line

   --  character (which is a single ASCII.LF character, even in systems

   --  which normally use CR/LF or some other sequence for line end).

   -----------------

   -- Subprograms --

   -----------------

   procedure Set_Special_Output (P : Output_Proc);

   --  Sets subsequent output to call procedure P. If P is null, then

   --  the call cancels the effect of a previous call, reverting the

   --  output to standard error or standard output depending on the

   --  mode at the time of previous call. Any exception generated by

   --  by calls to P is simply propagated to the caller of the routine

   --  causing the write operation.

   procedure Cancel_Special_Output;

   --  Cancels the effect of a call to Set_Special_Output, if any.

   --  The output is then directed to standard error or standard output

   --  depending on the last call to Set_Standard_Error or Set_Standard_Output.

   --  It is never an error to call Cancel_Special_Output. It has the same

   --  effect as calling Set_Special_Output (null).

   procedure Ignore_Output (S : String);

   --  Does nothing. To disable output, pass Ignore_Output'Access to

   --  Set_Special_Output.

   procedure Set_Standard_Error;

   --  Sets subsequent output to appear on the standard error file (whatever

   --  that might mean for the host operating system, if anything) when

   --  no special output is in effect. When a special output is in effect,

   --  the output will appear on standard error only after special output

   --  has been cancelled.

   procedure Set_Standard_Output;

   --  Sets subsequent output to appear on the standard output file (whatever

   --  that might mean for the host operating system, if anything) when

   --  no special output is in effect. When a special output is in effect,

   --  the output will appear on standard output only after special output

   --  has been cancelled. Output to standard output is the default mode

   --  before any call to either of the Set procedures.

   procedure Indent;

   --  Increases the current indentation level. Whenever a line is written

   --  (triggered by Eol), an appropriate amount of whitespace is added to the

   --  beginning of the line, wrapping around if it gets too long.

   procedure Outdent;

   --  Decreases the current indentation level

   procedure Write_Char (C : Character);

   --  Write one character to the standard output file. If the character is LF,

   --  this is equivalent to Write_Eol.

   procedure Write_Erase_Char (C : Character);

   --  If last character in buffer matches C, erase it, otherwise no effect

   procedure Write_Eol;

   --  Write an end of line (whatever is required by the system in use,

   --  e.g. CR/LF for DOS, or LF for Unix) to the standard output file.

   --  This routine also empties the line buffer, actually writing it

   --  to the file. Note that Write_Eol is the only routine that causes

   --  any actual output to be written. Trailing spaces are removed.

   procedure Write_Eol_Keep_Blanks;

   --  Similar as Write_Eol, except that trailing spaces are not removed

   procedure Write_Int (Val : Int);

   --  Write an integer value with no leading blanks or zeroes. Negative

   --  values are preceded by a minus sign).

   procedure Write_Spaces (N : Nat);

   --  Write N spaces

   procedure Write_Str (S : String);

   --  Write a string of characters to the standard output file. Note that

   --  end of line is normally handled separately using WRITE_EOL, but it

   --  is allowed for the string to contain LF (but not CR) characters,

   --  which are properly interpreted as end of line characters. The string

   --  may also contain horizontal tab characters.

   procedure Write_Line (S : String);

   --  Equivalent to Write_Str (S) followed by Write_Eol;

   function Column return Pos;

   pragma Inline (Column);

   --  Returns the number of the column about to be written (e.g. a value

   --  of 1 means the current line is empty).

   -------------------------

   -- Buffer Save/Restore --

   -------------------------

   --  This facility allows the current line buffer to be saved and restored

   type Saved_Output_Buffer is private;

   --  Type used for Save/Restore_Buffer

   Buffer_Max : constant := Hostparm.Max_Line_Length;

   --  Maximal size of a buffered output line

   function Save_Output_Buffer return Saved_Output_Buffer;

   --  Save current line buffer and reset line buffer to empty

   procedure Restore_Output_Buffer (S : Saved_Output_Buffer);

   --  Restore previously saved output buffer. The value in S is not affected

   --  so it is legitimate to restore a buffer more than once.

   --------------------------

   -- Debugging Procedures --

   --------------------------

   --  The following procedures are intended only for debugging purposes,

   --  for temporary insertion into the text in environments where a debugger

   --  is not available. They all have non-standard very short lower case

   --  names, precisely to make sure that they are only used for debugging!

   procedure w (C : Character);

   --  Dump quote, character, quote, followed by line return

   procedure w (S : String);

   --  Dump string followed by line return

   procedure w (V : Int);

   --  Dump integer followed by line return

   procedure w (B : Boolean);

   --  Dump Boolean followed by line return

   procedure w (L : String; C : Character);

   --  Dump contents of string followed by blank, quote, character, quote

   procedure w (L : String; S : String);

   --  Dump two strings separated by blanks, followed by line return

   procedure w (L : String; V : Int);

   --  Dump contents of string followed by blank, integer, line return

   procedure w (L : String; B : Boolean);

   --  Dump contents of string followed by blank, Boolean, line return

private

   --  Note: the following buffer and column position are maintained by the

   --  subprograms defined in this package, and cannot be directly modified or

   --  accessed by a client.

   Buffer : String (1 .. Buffer_Max + 1) := (others => '*');

   for Buffer'Alignment use 4;

   --  Buffer used to build output line. We do line buffering because it

   --  is needed for the support of the debug-generated-code option (-gnatD).

   --  Historically it was first added because on VMS, line buffering is

   --  needed with certain file formats. So in any case line buffering must

   --  be retained for this purpose, even if other reasons disappear. Note

   --  any attempt to write more output to a line than can fit in the buffer

   --  will be silently ignored. The alignment clause improves the efficiency

   --  of the save/restore procedures.

   Next_Col : Positive range 1 .. Buffer'Length + 1 := 1;

   --  Column about to be written

   type Saved_Output_Buffer is record

      Buffer          : String (1 .. Buffer_Max + 1);

      Next_Col        : Positive;

      Cur_Indentation : Natural;

   end record;

end Output;