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21f4052c5b
groff(1) has changed the internal layout for the .Lb doc strings, but to preserve backwards compatibility we cannot simply rename them, we need to create new aliases so that these will work with old and new macros. Signed-off-by: Guillem Jover <guillem@hadrons.org>
173 lines
4.6 KiB
Plaintext
173 lines
4.6 KiB
Plaintext
.\" $NetBSD: radixsort.3,v 1.12 2003/04/16 13:34:46 wiz Exp $
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.\"
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.\" Copyright (c) 1990, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" from: @(#)radixsort.3 8.2 (Berkeley) 1/27/94
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.\"
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.Dd January 27, 1994
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.Dt RADIXSORT 3bsd
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.Os
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.Sh NAME
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.Nm radixsort ,
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.Nm sradixsort
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.Nd radix sort
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.Sh LIBRARY
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.ds str-Lb-libbsd Utility functions from BSD systems (libbsd, \-lbsd)
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.ds doc-str-Lb-libbsd \*[str-Lb-libbsd]
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.Lb libbsd
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.Sh SYNOPSIS
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.In limits.h
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.In stdlib.h
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(See
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.Xr libbsd 7
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for include usage.)
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.Ft int
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.Fn radixsort "const unsigned char **base" "int nmemb" "const unsigned char *table" "unsigned endbyte"
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.Ft int
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.Fn sradixsort "const unsigned char **base" "int nmemb" "const unsigned char *table" "unsigned endbyte"
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.Sh DESCRIPTION
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The
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.Fn radixsort
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and
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.Fn sradixsort
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functions
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are implementations of radix sort.
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.Pp
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These functions sort an
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.Fa nmemb
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element array of pointers to byte strings, with
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the initial member of which is referenced by
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.Fa base .
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The byte strings may contain any values.
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End of strings is denoted
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by character which has same weight as user specified value
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.Fa endbyte .
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.Fa endbyte
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has to be between 0 and 255.
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.Pp
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Applications may specify a sort order by providing the
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.Fa table
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argument.
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If
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.Pf non- Dv NULL ,
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.Fa table
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must reference an array of
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.Dv UCHAR_MAX
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+ 1 bytes which contains the sort
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weight of each possible byte value.
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The end-of-string byte must have a sort weight of 0 or 255
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(for sorting in reverse order).
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More than one byte may have the same sort weight.
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The
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.Fa table
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argument
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is useful for applications which wish to sort different characters
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equally, for example, providing a table with the same weights
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for A-Z as for a-z will result in a case-insensitive sort.
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If
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.Fa table
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is NULL, the contents of the array are sorted in ascending order
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according to the
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.Tn ASCII
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order of the byte strings they reference and
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.Fa endbyte
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has a sorting weight of 0.
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.Pp
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The
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.Fn sradixsort
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function is stable, that is, if two elements compare as equal, their
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order in the sorted array is unchanged.
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The
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.Fn sradixsort
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function uses additional memory sufficient to hold
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.Fa nmemb
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pointers.
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.Pp
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The
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.Fn radixsort
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function is not stable, but uses no additional memory.
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.Pp
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These functions are variants of most-significant-byte radix sorting; in
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particular, see
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.An "D.E. Knuth" Ns 's
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.%T "Algorithm R"
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and section 5.2.5, exercise 10.
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They take linear time relative to the number of bytes in the strings.
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.Sh RETURN VALUES
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.Rv -std radixsort
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.Sh ERRORS
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.Bl -tag -width Er
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.It Bq Er EINVAL
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The value of the
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.Fa endbyte
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element of
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.Fa table
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is not 0 or 255.
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.El
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.Pp
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Additionally, the
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.Fn sradixsort
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function
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may fail and set
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.Va errno
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for any of the errors specified for the library routine
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.Xr malloc 3 .
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.Sh SEE ALSO
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.Xr sort 1 ,
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.Xr qsort 3
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.Pp
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.Rs
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.%A Knuth, D.E.
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.%D 1968
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.%B "The Art of Computer Programming"
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.%T "Sorting and Searching"
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.%V Vol. 3
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.%P pp. 170-178
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.Re
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.Rs
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.%A Paige, R.
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.%D 1987
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.%T "Three Partition Refinement Algorithms"
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.%J "SIAM J. Comput."
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.%V Vol. 16
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.%N No. 6
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.Re
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.Rs
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.%A McIlroy, P.
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.%D 1993
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.%B "Engineering Radix Sort"
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.%T "Computing Systems"
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.%V Vol. 6:1
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.%P pp. 5-27
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.Re
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.Sh HISTORY
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The
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.Fn radixsort
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function first appeared in
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.Bx 4.4 .
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