1.\" Copyright (c) 1990, 1991 The Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)radixsort.3 5.5 (Berkeley) 4/19/91 33.\" 34.Dd April 19, 1991 35.Dt RADIXSORT 3 36.Os 37.Sh NAME 38.Nm radixsort 39.Nd radix sort 40.Sh SYNOPSIS 41.Fd #include <limits.h> 42.Fd #include <stdlib.h> 43.Ft int 44.Fn radixsort "u_char **base" "int nmemb" "u_char *table" "u_char endbyte" 45.Sh DESCRIPTION 46The 47.Fn radixsort 48function 49is a modified radix sort. 50.Pp 51The 52.Fn radixsort 53function sorts an array of 54.Fa nmemb 55pointers to byte strings, the initial member of which is referenced 56by 57.Fa base . 58The byte strings may contain any values; the end of each string 59is denoted by the user-specified value 60.Fa endbyte . 61The contents of the array are sorted in ascending order according 62to the 63.Tn ASCII 64order of the byte strings they reference. 65.Pp 66Applications may specify a sort order by providing the 67.Fa table 68argument. 69If 70.Pf non- Dv NULL , 71.Fa table 72must reference an array of 73.Dv UCHAR_MAX 74+ 1 bytes which contains the sort 75weight of each possible byte value. 76The end-of-string byte must have a sort weight of 0. 77More than one byte may have the same sort weight. 78The 79.Fa table 80argument 81is useful for applications which wish to sort different characters 82equally; for example, providing a table with the same weights 83for A-Z as for a-z will result in a case-insensitive sort. 84.Pp 85The 86.Fn radixsort 87function 88is stable, that is, if two elements compare as equal, their order in 89the sorted array is unchanged. 90.Pp 91The 92.Fn radixsort 93function 94is a variant of most-significant-byte radix sorting; in particular, see 95D.E. Knuth's Algorithm R and section 5.2.5, exercise 10. 96The 97.Fn radixsort 98function 99takes linear time relative to the number of bytes in the strings. 100.Sh RETURN VALUES 101Upon successful completion 0 is returned. 102Otherwise, \-1 is returned and the global variable 103.Va errno 104is set to indicate the error. 105.Sh ERRORS 106The 107.Fn radixsort 108function 109may fail and set 110.Va errno 111for any of the errors specified for the library routine 112.Xr malloc 3 . 113.Sh SEE ALSO 114.Xr sort 1 , 115.Xr qsort 3 116.Pp 117.Rs 118.%A Knuth, D.E. 119.%D 1968 120.%B "The Art of Computer Programming" 121.%T "Sorting and Searching" 122.%V Vol. 3 123.%P pp. 170-178 124.Re 125.Rs 126.%A Paige, R. 127.%D 1987 128.%T "Three Partition Refinement Algorithms" 129.%J "SIAM J. Comput." 130.%V Vol. 16 131.%N No. 6 132.Re 133.Sh HISTORY 134The 135.Fn radixsort 136function is 137.Ud . 138.Sh BUGS 139The 140.Fa nmemb 141argument 142must be less than the maximum integer, 143.Dv INT_MAX . 144