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Diffstat (limited to 'gcc-4.9/gcc/ada/g-heasor.ads')
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1 files changed, 72 insertions, 0 deletions
diff --git a/gcc-4.9/gcc/ada/g-heasor.ads b/gcc-4.9/gcc/ada/g-heasor.ads new file mode 100644 index 000000000..edc9294e6 --- /dev/null +++ b/gcc-4.9/gcc/ada/g-heasor.ads @@ -0,0 +1,72 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT RUN-TIME COMPONENTS -- +-- -- +-- G N A T . H E A P _ S O R T -- +-- -- +-- 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. -- +-- -- +------------------------------------------------------------------------------ + +-- Sort utility (Using Heapsort Algorithm) + +-- This package provides a heapsort routine that works with access to +-- subprogram parameters, so that it can be used with different types with +-- shared sorting code. + +-- 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. + +-- See also GNAT.Heap_Sort_G which is a generic version that will be faster +-- since the overhead of the indirect calls is avoided, at the expense of +-- generic code duplication and less convenient interface. + +-- Note: GNAT.Heap_Sort replaces and obsoletes GNAT.Heap_Sort_A, which is +-- retained in the GNAT library for backwards compatibility. + +package GNAT.Heap_Sort is + pragma Pure; + + -- 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. + + type Xchg_Procedure is access procedure (Op1, Op2 : Natural); + -- A pointer to a procedure that exchanges the two data items whose + -- index values are Op1 and Op2. + + type Lt_Function is access function (Op1, Op2 : Natural) return Boolean; + -- A pointer to a function that compares two items and returns True if + -- the item with index value Op1 is less than the item with Index value + -- Op2, and False if the Op1 item is greater than the Op2 item. If + -- the items are equal, then it does not matter if True or False is + -- returned (but it is slightly more efficient to return False). + + procedure Sort (N : Natural; Xchg : Xchg_Procedure; Lt : Lt_Function); + -- This procedures sorts items in the range from 1 to N into ascending + -- order making calls to Lt to do required comparisons, and calls to + -- Xchg to exchange items. The sort is not stable, that is the order + -- of equal items in the input data set is not preserved. + +end GNAT.Heap_Sort; |