tries.c revision 50276 
1/****************************************************************************
2 * Copyright (c) 1998 Free Software Foundation, Inc.                        *
3 *                                                                          *
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5 * copy of this software and associated documentation files (the            *
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9 * copies of the Software, and to permit persons to whom the Software is    *
10 * furnished to do so, subject to the following conditions:                 *
11 *                                                                          *
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13 * in all copies or substantial portions of the Software.                   *
14 *                                                                          *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
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22 *                                                                          *
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26 * authorization.                                                           *
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28
29/****************************************************************************
30 *  Author: Thomas E. Dickey <dickey@clark.net> 1997                        *
31 ****************************************************************************/
32
33/*
34**	tries.c
35**
36**	Functions to manage the tree of partial-completions for keycodes.
37**
38*/
39
40#include <curses.priv.h>
41
42MODULE_ID("$Id: tries.c,v 1.12 1999/03/01 23:23:59 tom Exp $")
43
44/*
45 * Expand a keycode into the string that it corresponds to, returning null if
46 * no match was found, otherwise allocating a string of the result.
47 */
48char *_nc_expand_try(struct tries *tree, unsigned short code, int *count, size_t len)
49{
50	struct tries *ptr = tree;
51	char *result = 0;
52
53	if (code != 0) {
54		while (ptr != 0) {
55			if ((result = _nc_expand_try(ptr->child, code, count, len + 1)) != 0) {
56				break;
57			}
58			if (ptr->value == code) {
59				*count -= 1;
60				if (*count == -1) {
61					result = typeCalloc(char, len+2);
62					break;
63				}
64			}
65			ptr = ptr->sibling;
66		}
67	}
68	if (result != 0) {
69		if ((result[len] = ptr->ch) == 0)
70			*((unsigned char *)(result+len)) = 128;
71#ifdef TRACE
72		if (len == 0)
73			_tracef("expand_key %s %s", _trace_key(code), _nc_visbuf(result));
74#endif
75	}
76	return result;
77}
78
79/*
80 * Remove a code from the specified tree, freeing the unused nodes.  Returns
81 * true if the code was found/removed.
82 */
83int _nc_remove_key(struct tries **tree, unsigned short code)
84{
85	T((T_CALLED("_nc_remove_key(%p,%d)"), tree, code));
86
87	if (code == 0)
88		returnCode(FALSE);
89
90	while (*tree != 0) {
91		if (_nc_remove_key(&(*tree)->child, code)) {
92			returnCode(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			returnCode(TRUE);
104		}
105		tree = &(*tree)->sibling;
106	}
107	returnCode(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 */
114int _nc_remove_string(struct tries **tree, char *string)
115{
116	T((T_CALLED("_nc_remove_string(%p,%s)"), tree, _nc_visbuf(string)));
117
118	if (string == 0 || *string == 0)
119		returnCode(FALSE);
120
121	while (*tree != 0) {
122		if ((unsigned char)(*tree)->ch == (unsigned char)*string) {
123			if (string[1] != 0)
124				returnCode(_nc_remove_string(&(*tree)->child, string+1));
125			if((*tree)->child) {
126				/* don't cut the whole sub-tree */
127				(*tree)->value = 0;
128			} else {
129				struct tries *to_free = *tree;
130				*tree = (*tree)->sibling;
131				free(to_free);
132			}
133			returnCode(TRUE);
134		}
135		tree = &(*tree)->sibling;
136	}
137	returnCode(FALSE);
138}
139