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Diffstat (limited to 'gcc/ada/a-tigeli.adb')
| -rw-r--r-- | gcc/ada/a-tigeli.adb | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/gcc/ada/a-tigeli.adb b/gcc/ada/a-tigeli.adb new file mode 100644 index 000000000..c23cd3478 --- /dev/null +++ b/gcc/ada/a-tigeli.adb @@ -0,0 +1,227 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT RUN-TIME COMPONENTS -- +-- -- +-- A D A . T E X T _ I O . G E T _ L I N E -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 1992-2010, 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. -- +-- -- +------------------------------------------------------------------------------ + +-- The implementation of Ada.Text_IO.Get_Line is split into a subunit so that +-- different implementations can be used on different systems. This is the +-- standard implementation (it uses low level features not suitable for use +-- in the JVM or .NET implementations). + +with System; use System; +with System.Storage_Elements; use System.Storage_Elements; + +separate (Ada.Text_IO) +procedure Get_Line + (File : File_Type; + Item : out String; + Last : out Natural) +is + Chunk_Size : constant := 80; + -- We read into a fixed size auxiliary buffer. Because this buffer + -- needs to be pre-initialized, there is a trade-off between size and + -- speed. Experiments find returns are diminishing after 50 and this + -- size allows most lines to be processed with a single read. + + ch : int; + N : Natural; + + procedure memcpy (s1, s2 : chars; n : size_t); + pragma Import (C, memcpy); + + function memchr (s : chars; ch : int; n : size_t) return chars; + pragma Import (C, memchr); + + procedure memset (b : chars; ch : int; n : size_t); + pragma Import (C, memset); + + function Get_Chunk (N : Positive) return Natural; + -- Reads at most N - 1 characters into Item (Last + 1 .. Item'Last), + -- updating Last. Raises End_Error if nothing was read (End_Of_File). + -- Returns number of characters still to read (either 0 or 1) in + -- case of success. + + --------------- + -- Get_Chunk -- + --------------- + + function Get_Chunk (N : Positive) return Natural is + Buf : String (1 .. Chunk_Size); + S : constant chars := Buf (1)'Address; + P : chars; + + begin + if N = 1 then + return N; + end if; + + memset (S, 10, size_t (N)); + + if fgets (S, N, File.Stream) = Null_Address then + if ferror (File.Stream) /= 0 then + raise Device_Error; + + -- If incomplete last line, pretend we found a LM + + elsif Last >= Item'First then + return 0; + + else + raise End_Error; + end if; + end if; + + P := memchr (S, LM, size_t (N)); + + -- If no LM is found, the buffer got filled without reading a new + -- line. Otherwise, the LM is either one from the input, or else one + -- from the initialization, which means an incomplete end-of-line was + -- encountered. Only in first case the LM will be followed by a 0. + + if P = Null_Address then + pragma Assert (Buf (N) = ASCII.NUL); + memcpy (Item (Last + 1)'Address, + Buf (1)'Address, size_t (N - 1)); + Last := Last + N - 1; + + return 1; + + else + -- P points to the LM character. Set K so Buf (K) is the character + -- right before. + + declare + K : Natural := Natural (P - S); + + begin + -- Now Buf (K + 2) should be 0, or otherwise Buf (K) is the 0 + -- put in by fgets, so compensate. + + if K + 2 > Buf'Last or else Buf (K + 2) /= ASCII.NUL then + + -- Incomplete last line, so remove the extra 0 + + pragma Assert (Buf (K) = ASCII.NUL); + K := K - 1; + end if; + + memcpy (Item (Last + 1)'Address, + Buf (1)'Address, size_t (K)); + Last := Last + K; + end; + + return 0; + end if; + end Get_Chunk; + +-- Start of processing for Get_Line + +begin + FIO.Check_Read_Status (AP (File)); + + -- Immediate exit for null string, this is a case in which we do not + -- need to test for end of file and we do not skip a line mark under + -- any circumstances. + + if Item'First > Item'Last then + return; + end if; + + N := Item'Last - Item'First + 1; + + Last := Item'First - 1; + + -- Here we have at least one character, if we are immediately before + -- a line mark, then we will just skip past it storing no characters. + + if File.Before_LM then + File.Before_LM := False; + File.Before_LM_PM := False; + + -- Otherwise we need to read some characters + + else + while N >= Chunk_Size loop + if Get_Chunk (Chunk_Size) = 0 then + N := 0; + else + N := N - Chunk_Size + 1; + end if; + end loop; + + if N > 1 then + N := Get_Chunk (N); + end if; + + -- Almost there, only a little bit more to read + + if N = 1 then + ch := Getc (File); + + -- If we get EOF after already reading data, this is an incomplete + -- last line, in which case no End_Error should be raised. + + if ch = EOF and then Last < Item'First then + raise End_Error; + + elsif ch /= LM then + + -- Buffer really is full without having seen LM, update col + + Last := Last + 1; + Item (Last) := Character'Val (ch); + File.Col := File.Col + Count (Last - Item'First + 1); + return; + end if; + end if; + end if; + + -- We have skipped past, but not stored, a line mark. Skip following + -- page mark if one follows, but do not do this for a non-regular file + -- (since otherwise we get annoying wait for an extra character) + + File.Line := File.Line + 1; + File.Col := 1; + + if File.Before_LM_PM then + File.Line := 1; + File.Before_LM_PM := False; + File.Page := File.Page + 1; + + elsif File.Is_Regular_File then + ch := Getc (File); + + if ch = PM and then File.Is_Regular_File then + File.Line := 1; + File.Page := File.Page + 1; + else + Ungetc (ch, File); + end if; + end if; +end Get_Line; |