xref: /openbsd-src/lib/libcurses/base/tries.c (revision c21ba70dd518c922f8dfa93d6c24c449ab5763d9)
1 /*	$OpenBSD: tries.c,v 1.2 1999/02/24 06:31:08 millert Exp $	*/
2 
3 /****************************************************************************
4  * Copyright (c) 1998 Free Software Foundation, Inc.                        *
5  *                                                                          *
6  * Permission is hereby granted, free of charge, to any person obtaining a  *
7  * copy of this software and associated documentation files (the            *
8  * "Software"), to deal in the Software without restriction, including      *
9  * without limitation the rights to use, copy, modify, merge, publish,      *
10  * distribute, distribute with modifications, sublicense, and/or sell       *
11  * copies of the Software, and to permit persons to whom the Software is    *
12  * furnished to do so, subject to the following conditions:                 *
13  *                                                                          *
14  * The above copyright notice and this permission notice shall be included  *
15  * in all copies or substantial portions of the Software.                   *
16  *                                                                          *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
19  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
20  * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
21  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
22  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
23  * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
24  *                                                                          *
25  * Except as contained in this notice, the name(s) of the above copyright   *
26  * holders shall not be used in advertising or otherwise to promote the     *
27  * sale, use or other dealings in this Software without prior written       *
28  * authorization.                                                           *
29  ****************************************************************************/
30 
31 /****************************************************************************
32  *  Author: Thomas E. Dickey <dickey@clark.net> 1997                        *
33  ****************************************************************************/
34 
35 /*
36 **	tries.c
37 **
38 **	Functions to manage the tree of partial-completions for keycodes.
39 **
40 */
41 
42 #include <curses.priv.h>
43 
44 MODULE_ID("$From: tries.c,v 1.10 1999/02/19 11:52:11 tom Exp $")
45 
46 /*
47  * Expand a keycode into the string that it corresponds to, returning null if
48  * no match was found, otherwise allocating a string of the result.
49  */
50 char *_nc_expand_try(struct tries *tree, unsigned short code, int *count, size_t len)
51 {
52 	struct tries *ptr = tree;
53 	char *result = 0;
54 
55 	if (code != 0) {
56 		while (ptr != 0) {
57 			if ((result = _nc_expand_try(ptr->child, code, count, len + 1)) != 0) {
58 				break;
59 			}
60 			if (ptr->value == code) {
61 				*count -= 1;
62 				if (*count == -1) {
63 					result = typeCalloc(char, len+2);
64 					break;
65 				}
66 			}
67 			ptr = ptr->sibling;
68 		}
69 	}
70 	if (result != 0) {
71 		if ((result[len] = ptr->ch) == 0)
72 			*((unsigned char *)(result+len)) = 128;
73 #ifdef TRACE
74 		if (len == 0)
75 			_tracef("expand_key %s %s", _trace_key(code), _nc_visbuf(result));
76 #endif
77 	}
78 	return result;
79 }
80 
81 /*
82  * Remove a code from the specified tree, freeing the unused nodes.  Returns
83  * true if the code was found/removed.
84  */
85 int _nc_remove_key(struct tries **tree, unsigned short code)
86 {
87 	if (code == 0)
88 		return FALSE;
89 
90 	while (*tree != 0) {
91 		if (_nc_remove_key(&(*tree)->child, code)) {
92 			return TRUE;
93 		}
94 		if ((*tree)->value == code) {
95 			if((*tree)->child) {
96 				/* don't cut the whole sub-tree */
97 				(*tree)->value = 0;
98 			} else {
99 				struct tries *to_free = *tree;
100 				*tree = (*tree)->sibling;
101 				free(to_free);
102 			}
103 			return TRUE;
104 		}
105 		tree = &(*tree)->sibling;
106 	}
107 	return FALSE;
108 }
109 
110 /*
111  * Remove a string from the specified tree, freeing the unused nodes.  Returns
112  * true if the string was found/removed.
113  */
114 int _nc_remove_string(struct tries **tree, char *string)
115 {
116 	if (string == 0 || *string == 0)
117 		return FALSE;
118 
119 	while (*tree != 0) {
120 		if (_nc_remove_string(&(*tree)->child, string+1)) {
121 			return TRUE;
122 		}
123 		if ((unsigned char)(*tree)->ch == (unsigned char)*string) {
124 			if((*tree)->child) {
125 				/* don't cut the whole sub-tree */
126 				(*tree)->value = 0;
127 			} else {
128 				struct tries *to_free = *tree;
129 				*tree = (*tree)->sibling;
130 				free(to_free);
131 			}
132 			return TRUE;
133 		}
134 		tree = &(*tree)->sibling;
135 	}
136 	return FALSE;
137 }
138