mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-22 11:17:19 +00:00
162 lines
4.6 KiB
Groff
162 lines
4.6 KiB
Groff
.\" Copyright (c) 1990, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the University of
|
|
.\" California, Berkeley and its contributors.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)radixsort.3 8.2 (Berkeley) 1/27/94
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd January 27, 1994
|
|
.Dt RADIXSORT 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm radixsort
|
|
.Nd radix sort
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.Fd #include <limits.h>
|
|
.Fd #include <stdlib.h>
|
|
.Ft int
|
|
.Fn radixsort "const unsigned char **base" "int nmemb" "const unsigned char *table" "unsigned endbyte"
|
|
.Ft int
|
|
.Fn sradixsort "const unsigned char **base" "int nmemb" "const unsigned char *table" "unsigned endbyte"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn radixsort
|
|
and
|
|
.Fn sradixsort
|
|
functions
|
|
are implementations of radix sort.
|
|
.Pp
|
|
These functions sort an array of pointers to byte strings, the initial
|
|
member of which is referenced by
|
|
.Fa base .
|
|
The byte strings may contain any values; the end of each string
|
|
is denoted by the user-specified value
|
|
.Fa endbyte .
|
|
.Pp
|
|
Applications may specify a sort order by providing the
|
|
.Fa table
|
|
argument.
|
|
If
|
|
.Pf non- Dv NULL ,
|
|
.Fa table
|
|
must reference an array of
|
|
.Dv UCHAR_MAX
|
|
+ 1 bytes which contains the sort
|
|
weight of each possible byte value.
|
|
The end-of-string byte must have a sort weight of 0 or 255
|
|
(for sorting in reverse order).
|
|
More than one byte may have the same sort weight.
|
|
The
|
|
.Fa table
|
|
argument
|
|
is useful for applications which wish to sort different characters
|
|
equally, for example, providing a table with the same weights
|
|
for A-Z as for a-z will result in a case-insensitive sort.
|
|
If
|
|
.Fa table
|
|
is NULL, the contents of the array are sorted in ascending order
|
|
according to the
|
|
.Tn ASCII
|
|
order of the byte strings they reference and
|
|
.Fa endbyte
|
|
has a sorting weight of 0.
|
|
.Pp
|
|
The
|
|
.Fn sradixsort
|
|
function is stable, that is, if two elements compare as equal, their
|
|
order in the sorted array is unchanged.
|
|
The
|
|
.Fn sradixsort
|
|
function uses additional memory sufficient to hold
|
|
.Fa nmemb
|
|
pointers.
|
|
.Pp
|
|
The
|
|
.Fn radixsort
|
|
function is not stable, but uses no additional memory.
|
|
.Pp
|
|
These functions are variants of most-significant-byte radix sorting; in
|
|
particular, see D.E. Knuth's Algorithm R and section 5.2.5, exercise 10.
|
|
They take linear time relative to the number of bytes in the strings.
|
|
.Sh RETURN VALUES
|
|
.Rv -std radixsort
|
|
.Sh ERRORS
|
|
.Bl -tag -width Er
|
|
.It Bq Er EINVAL
|
|
The value of the
|
|
.Fa endbyte
|
|
element of
|
|
.Fa table
|
|
is not 0 or 255.
|
|
.El
|
|
.Pp
|
|
Additionally, the
|
|
.Fn sradixsort
|
|
function
|
|
may fail and set
|
|
.Va errno
|
|
for any of the errors specified for the library routine
|
|
.Xr malloc 3 .
|
|
.Sh SEE ALSO
|
|
.Xr sort 1 ,
|
|
.Xr qsort 3
|
|
.Pp
|
|
.Rs
|
|
.%A Knuth, D.E.
|
|
.%D 1968
|
|
.%B "The Art of Computer Programming"
|
|
.%T "Sorting and Searching"
|
|
.%V Vol. 3
|
|
.%P pp. 170-178
|
|
.Re
|
|
.Rs
|
|
.%A Paige, R.
|
|
.%D 1987
|
|
.%T "Three Partition Refinement Algorithms"
|
|
.%J "SIAM J. Comput."
|
|
.%V Vol. 16
|
|
.%N No. 6
|
|
.Re
|
|
.Rs
|
|
.%A McIlroy, P.
|
|
.%D 1993
|
|
.%B "Engineering Radix Sort"
|
|
.%T "Computing Systems"
|
|
.%V Vol. 6:1
|
|
.%P pp. 5-27
|
|
.Re
|
|
.Sh HISTORY
|
|
The
|
|
.Fn radixsort
|
|
function first appeared in
|
|
.Bx 4.4 .
|