1.\" $NetBSD$ 2.\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com> 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. The name of the author may not be used to endorse or promote products 14.\" derived from this software without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 17.\" INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 18.\" AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 19.\" THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 20.\" EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 21.\" PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 22.\" OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 23.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 24.\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 25.\" ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26.\" 27.\" OpenBSD: tsearch.3,v 1.2 1998/06/21 22:13:49 millert Exp 28.\" $FreeBSD$ 29.\" 30.Dd June 15, 1997 31.Dt TSEARCH 3 32.Os 33.Sh NAME 34.Nm tsearch , tfind , tdelete , twalk 35.Nd manipulate binary search trees 36.Sh SYNOPSIS 37.In search.h 38.Ft void * 39.Fn tdelete "const void * restrict key" "void ** restrict rootp" "int (*compar) (const void *, const void *)" 40.Ft void * 41.Fn tfind "const void *key" "void * const *rootp" "int (*compar) (const void *, const void *)" 42.Ft void * 43.Fn tsearch "const void *key" "void **rootp" "int (*compar) (const void *, const void *)" 44.Ft void 45.Fn twalk "const void *root" "void (*compar) (const void *, VISIT, int)" 46.Sh DESCRIPTION 47The 48.Fn tdelete , 49.Fn tfind , 50.Fn tsearch , 51and 52.Fn twalk 53functions manage binary search trees based on algorithms T and D 54from Knuth (6.2.2). The comparison function passed in by 55the user has the same style of return values as 56.Xr strcmp 3 . 57.Pp 58The 59.Fn tfind 60function 61searches for the datum matched by the argument 62.Fa key 63in the binary tree rooted at 64.Fa rootp , 65returning a pointer to the datum if it is found and NULL 66if it is not. 67.Pp 68The 69.Fn tsearch 70function 71is identical to 72.Fn tfind 73except that if no match is found, 74.Fa key 75is inserted into the tree and a pointer to it is returned. If 76.Fa rootp 77points to a NULL value a new binary search tree is created. 78.Pp 79The 80.Fn tdelete 81function 82deletes a node from the specified binary search tree and returns 83a pointer to the parent of the node to be deleted. 84It takes the same arguments as 85.Fn tfind 86and 87.Fn tsearch . 88If the node to be deleted is the root of the binary search tree, 89.Fa rootp 90will be adjusted. 91.Pp 92The 93.Fn twalk 94function 95walks the binary search tree rooted in 96.Fa root 97and calls the function 98.Fa action 99on each node. 100The 101.Fa action 102function 103is called with three arguments: a pointer to the current node, 104a value from the enum 105.Sy "typedef enum { preorder, postorder, endorder, leaf } VISIT;" 106specifying the traversal type, and a node level (where level 107zero is the root of the tree). 108.Sh SEE ALSO 109.Xr bsearch 3 , 110.Xr hsearch 3 , 111.Xr lsearch 3 112.Sh RETURN VALUES 113The 114.Fn tsearch 115function returns NULL if allocation of a new node fails (usually 116due to a lack of free memory). 117.Pp 118The 119.Fn tfind , 120.Fn tsearch , 121and 122.Fn tdelete 123functions 124return NULL if 125.Fa rootp 126is NULL or the datum cannot be found. 127.Pp 128The 129.Fn twalk 130function returns no value. 131