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Diffstat (limited to 'gcc/ada/libgnat/a-ststbo.adb')
| -rw-r--r-- | gcc/ada/libgnat/a-ststbo.adb | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/gcc/ada/libgnat/a-ststbo.adb b/gcc/ada/libgnat/a-ststbo.adb new file mode 100644 index 0000000..3b31acc --- /dev/null +++ b/gcc/ada/libgnat/a-ststbo.adb @@ -0,0 +1,115 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT LIBRARY COMPONENTS -- +-- -- +-- A D A . S T R E A M S . S T O R A G E . B O U N D E D -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 2020, 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/>. -- +-- -- +------------------------------------------------------------------------------ + +pragma Ada_2020; +package body Ada.Streams.Storage.Bounded is + + ---------- + -- Read -- + ---------- + + overriding procedure Read + (Stream : in out Stream_Type; Item : out Stream_Element_Array; + Last : out Stream_Element_Offset) + is + EA : Stream_Element_Array renames + Stream.Elements (1 .. Element_Count (Stream)); + begin + if Item'Length = 0 then + Last := Item'First - 1; + + -- If the entire content of the stream fits in Item, then copy it and + -- clear the stream. This is likely the usual case. + + elsif Element_Count (Stream) <= Item'Length then + Last := Item'First + Element_Count (Stream) - 1; + Item (Item'First .. Last) := EA; + Clear (Stream); + + -- Otherwise, copy as much into Item as will fit. Then slide the + -- remaining part of the stream down, and compute the new Count. + -- We expect this to be the unusual case, so the cost of copying + -- the remaining part probably doesn't matter. + + else + Last := Item'Last; + + declare + New_Count : constant Stream_Element_Count := + Element_Count (Stream) - Item'Length; + begin + Item := EA (1 .. Item'Length); + EA (1 .. New_Count) := + EA (Element_Count (Stream) - New_Count + 1 .. + Element_Count (Stream)); + Stream.Count := New_Count; + end; + end if; + end Read; + + ----------- + -- Write -- + ----------- + + overriding procedure Write + (Stream : in out Stream_Type; Item : Stream_Element_Array) + is + pragma Assert + (Element_Count (Stream) + Item'Length <= Stream.Max_Elements + or else (raise Constraint_Error)); + -- That is a precondition in the RM + + New_Count : constant Stream_Element_Count := + Element_Count (Stream) + Item'Length; + begin + Stream.Elements (Element_Count (Stream) + 1 .. New_Count) := Item; + Stream.Count := New_Count; + end Write; + + ------------------- + -- Element_Count -- + ------------------- + + overriding function Element_Count + (Stream : Stream_Type) return Stream_Element_Count + is + begin + return Stream.Count; + end Element_Count; + + ----------- + -- Clear -- + ----------- + + overriding procedure Clear (Stream : in out Stream_Type) + is + begin + Stream.Count := 0; + end Clear; + +end Ada.Streams.Storage.Bounded; |