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 (*action) (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). 55The comparison function passed in by 56the user has the same style of return values as 57.Xr strcmp 3 . 58.Pp 59The 60.Fn tfind 61function 62searches for the datum matched by the argument 63.Fa key 64in the binary tree rooted at 65.Fa rootp , 66returning a pointer to the datum if it is found and NULL 67if it is not. 68.Pp 69The 70.Fn tsearch 71function 72is identical to 73.Fn tfind 74except that if no match is found, 75.Fa key 76is inserted into the tree and a pointer to it is returned. 77If 78.Fa rootp 79points to a NULL value a new binary search tree is created. 80.Pp 81The 82.Fn tdelete 83function 84deletes a node from the specified binary search tree and returns 85a pointer to the parent of the node to be deleted. 86It takes the same arguments as 87.Fn tfind 88and 89.Fn tsearch . 90If the node to be deleted is the root of the binary search tree, 91.Fa rootp 92will be adjusted. 93.Pp 94The 95.Fn twalk 96function 97walks the binary search tree rooted in 98.Fa root 99and calls the function 100.Fa action 101on each node. 102The 103.Fa action 104function 105is called with three arguments: a pointer to the current node, 106a value from the enum 107.Sy "typedef enum { preorder, postorder, endorder, leaf } VISIT;" 108specifying the traversal type, and a node level (where level 109zero is the root of the tree). 110.Sh RETURN VALUES 111The 112.Fn tsearch 113function returns NULL if allocation of a new node fails (usually 114due to a lack of free memory). 115.Pp 116The 117.Fn tfind , 118.Fn tsearch , 119and 120.Fn tdelete 121functions 122return NULL if 123.Fa rootp 124is NULL or the datum cannot be found. 125.Pp 126The 127.Fn twalk 128function returns no value. 129.Sh SEE ALSO 130.Xr bsearch 3 , 131.Xr hsearch 3 , 132.Xr lsearch 3 133