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: src/lib/libc/stdlib/tsearch.3,v 1.15 2006/06/23 13:36:33 keramida Exp $ 29.\" $DragonFly: src/lib/libc/stdlib/tsearch.c,v 1.6 2005/11/24 17:18:30 swildner Exp $ 30.\" 31.Dd June 15, 1997 32.Dt TSEARCH 3 33.Os 34.Sh NAME 35.Nm tsearch , 36.Nm tfind , 37.Nm tdelete , 38.Nm twalk 39.Nd manipulate binary search trees 40.Sh LIBRARY 41.Lb libc 42.Sh SYNOPSIS 43.In search.h 44.Ft void * 45.Fn tdelete "const void * restrict key" "void ** restrict rootp" "int (*compar) (const void *, const void *)" 46.Ft void * 47.Fn tfind "const void *key" "void * const *rootp" "int (*compar) (const void *, const void *)" 48.Ft void * 49.Fn tsearch "const void *key" "void **rootp" "int (*compar) (const void *, const void *)" 50.Ft void 51.Fn twalk "const void *root" "void (*action) (const void *, VISIT, int)" 52.Sh DESCRIPTION 53The 54.Fn tdelete , 55.Fn tfind , 56.Fn tsearch , 57and 58.Fn twalk 59functions manage binary search trees based on algorithms T and D 60from Knuth (6.2.2). 61The comparison function passed in by 62the user has the same style of return values as 63.Xr strcmp 3 . 64.Pp 65The 66.Fn tfind 67function 68searches for the datum matched by the argument 69.Fa key 70in the binary tree rooted at 71.Fa rootp , 72returning a pointer to the datum if it is found and NULL 73if it is not. 74.Pp 75The 76.Fn tsearch 77function 78is identical to 79.Fn tfind 80except that if no match is found, 81.Fa key 82is inserted into the tree and a pointer to it is returned. 83If 84.Fa rootp 85points to a NULL value a new binary search tree is created. 86.Pp 87The 88.Fn tdelete 89function 90deletes a node from the specified binary search tree and returns 91a pointer to the parent of the node to be deleted. 92It takes the same arguments as 93.Fn tfind 94and 95.Fn tsearch . 96If the node to be deleted is the root of the binary search tree, 97.Fa rootp 98will be adjusted. 99.Pp 100The 101.Fn twalk 102function 103walks the binary search tree rooted in 104.Fa root 105and calls the function 106.Fa action 107on each node. 108The 109.Fa action 110function 111is called with three arguments: a pointer to the current node, 112a value from the enum 113.Sy "typedef enum { preorder, postorder, endorder, leaf } VISIT;" 114specifying the traversal type, and a node level (where level 115zero is the root of the tree). 116.Sh RETURN VALUES 117The 118.Fn tsearch 119function returns NULL if allocation of a new node fails (usually 120due to a lack of free memory). 121.Pp 122The 123.Fn tfind , 124.Fn tsearch , 125and 126.Fn tdelete 127functions 128return NULL if 129.Fa rootp 130is NULL or the datum cannot be found. 131.Pp 132The 133.Fn twalk 134function returns no value. 135.Sh SEE ALSO 136.Xr bsearch 3 , 137.Xr hsearch 3 , 138.Xr lsearch 3 139