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Diffstat (limited to 'gcc-4.8.1/gcc/ada/g-hesorg.ads')
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diff --git a/gcc-4.8.1/gcc/ada/g-hesorg.ads b/gcc-4.8.1/gcc/ada/g-hesorg.ads new file mode 100644 index 000000000..57b991237 --- /dev/null +++ b/gcc-4.8.1/gcc/ada/g-hesorg.ads @@ -0,0 +1,88 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT RUN-TIME COMPONENTS -- +-- -- +-- G N A T . H E A P _ S O R T _ G -- +-- -- +-- S p e c -- +-- -- +-- Copyright (C) 1995-2010, 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. -- +-- -- +------------------------------------------------------------------------------ + +-- Heapsort generic package using formal procedures + +-- This package provides a generic heapsort routine that can be used with +-- different types of data. + +-- See also GNAT.Heap_Sort, a version that works with subprogram access +-- parameters, allowing code sharing. The generic version is slightly more +-- efficient but does not allow code sharing and has an interface that is +-- more awkward to use. + +-- There is also GNAT.Heap_Sort_A, which is now considered obsolete, but +-- was an older version working with subprogram parameters. This version +-- is retained for backwards compatibility with old versions of GNAT. + +-- This heapsort algorithm uses approximately N*log(N) compares in the +-- worst case and is in place with no additional storage required. See +-- the body for exact details of the algorithm used. + +generic + -- The data to be sorted is assumed to be indexed by integer values from + -- 1 to N, where N is the number of items to be sorted. In addition, the + -- index value zero is used for a temporary location used during the sort. + + with procedure Move (From : Natural; To : Natural); + -- A procedure that moves the data item with index value From to the data + -- item with index value To (the old value in To being lost). An index + -- value of zero is used for moves from and to a single temporary location. + -- For best efficiency, this routine should be marked as inlined. + + with function Lt (Op1, Op2 : Natural) return Boolean; + -- A function that compares two items and returns True if the item with + -- index Op1 is less than the item with Index Op2, and False if the Op1 + -- item is greater than the Op2 item. If the two items are equal, then + -- it does not matter whether True or False is returned (it is slightly + -- more efficient to return False). For best efficiency, this routine + -- should be marked as inlined. + + -- Note on use of temporary location + + -- There are two ways of providing for the index value zero to represent + -- a temporary value. Either an extra location can be allocated at the + -- start of the array, or alternatively the Move and Lt subprograms can + -- test for the case of zero and treat it specially. In any case it is + -- desirable to specify the two subprograms as inlined and the tests for + -- zero will in this case be resolved at instantiation time. + +package GNAT.Heap_Sort_G is + pragma Pure; + + procedure Sort (N : Natural); + -- This procedures sorts items in the range from 1 to N into ascending + -- order making calls to Lt to do required comparisons, and Move to move + -- items around. Note that, as described above, both Move and Lt use a + -- single temporary location with index value zero. This sort is not + -- stable, i.e. the order of equal elements in the input is not preserved. + +end GNAT.Heap_Sort_G; |