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Diffstat (limited to 'gcc/ada/libgnat/g-io_aux.adb')
| -rw-r--r-- | gcc/ada/libgnat/g-io_aux.adb | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/gcc/ada/libgnat/g-io_aux.adb b/gcc/ada/libgnat/g-io_aux.adb new file mode 100644 index 0000000..1e5c27d --- /dev/null +++ b/gcc/ada/libgnat/g-io_aux.adb @@ -0,0 +1,105 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT RUN-TIME COMPONENTS -- +-- -- +-- G N A T . I O _ A U X -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 1995-2017, AdaCore -- +-- -- +-- 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. -- +-- -- +------------------------------------------------------------------------------ + +with Interfaces.C_Streams; use Interfaces.C_Streams; + +package body GNAT.IO_Aux is + + Buflen : constant := 2000; + -- Buffer length. Works for any non-zero value, larger values take + -- more stack space, smaller values require more recursion. + + ----------------- + -- File_Exists -- + ----------------- + + function File_Exists (Name : String) return Boolean + is + Namestr : aliased String (1 .. Name'Length + 1); + -- Name as given with ASCII.NUL appended + + begin + Namestr (1 .. Name'Length) := Name; + Namestr (Name'Length + 1) := ASCII.NUL; + return file_exists (Namestr'Address) /= 0; + end File_Exists; + + -------------- + -- Get_Line -- + -------------- + + -- Current_Input case + + function Get_Line return String is + Buffer : String (1 .. Buflen); + -- Buffer to read in chunks of remaining line. Will work with any + -- size buffer. We choose a length so that most of the time no + -- recursion will be required. + + Last : Natural; + + begin + Ada.Text_IO.Get_Line (Buffer, Last); + + -- If the buffer is not full, then we are all done + + if Last < Buffer'Last then + return Buffer (1 .. Last); + + -- Otherwise, we still have characters left on the line. Note that + -- as specified by (RM A.10.7(19)) the end of line is not skipped + -- in this case, even if we are right at it now. + + else + return Buffer & GNAT.IO_Aux.Get_Line; + end if; + end Get_Line; + + -- Case of reading from a specified file. Note that we could certainly + -- share code between these two versions, but these are very short + -- routines, and we may as well aim for maximum speed, cutting out an + -- intermediate call (calls returning string may be somewhat slow) + + function Get_Line (File : Ada.Text_IO.File_Type) return String is + Buffer : String (1 .. Buflen); + Last : Natural; + + begin + Ada.Text_IO.Get_Line (File, Buffer, Last); + + if Last < Buffer'Last then + return Buffer (1 .. Last); + else + return Buffer & Get_Line (File); + end if; + end Get_Line; + +end GNAT.IO_Aux; |