tries.c revision 76726 
1/****************************************************************************
2 * Copyright (c) 1998,2000 Free Software Foundation, Inc.                   *
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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 1.14 2000/12/10 02:43:28 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 */
48NCURSES_EXPORT(char *)
49_nc_expand_try
50(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))
58		!= 0) {
59		break;
60	    }
61	    if (ptr->value == code) {
62		*count -= 1;
63		if (*count == -1) {
64		    result = typeCalloc(char, len + 2);
65		    break;
66		}
67	    }
68	    ptr = ptr->sibling;
69	}
70    }
71    if (result != 0) {
72	if ((result[len] = ptr->ch) == 0)
73	    *((unsigned char *) (result + len)) = 128;
74#ifdef TRACE
75	if (len == 0)
76	    _tracef("expand_key %s %s", _trace_key(code), _nc_visbuf(result));
77#endif
78    }
79    return result;
80}
81
82/*
83 * Remove a code from the specified tree, freeing the unused nodes.  Returns
84 * true if the code was found/removed.
85 */
86NCURSES_EXPORT(int)
87_nc_remove_key
88(struct tries **tree, unsigned short code)
89{
90    T((T_CALLED("_nc_remove_key(%p,%d)"), tree, code));
91
92    if (code == 0)
93	returnCode(FALSE);
94
95    while (*tree != 0) {
96	if (_nc_remove_key(&(*tree)->child, code)) {
97	    returnCode(TRUE);
98	}
99	if ((*tree)->value == code) {
100	    if ((*tree)->child) {
101		/* don't cut the whole sub-tree */
102		(*tree)->value = 0;
103	    } else {
104		struct tries *to_free = *tree;
105		*tree = (*tree)->sibling;
106		free(to_free);
107	    }
108	    returnCode(TRUE);
109	}
110	tree = &(*tree)->sibling;
111    }
112    returnCode(FALSE);
113}
114
115/*
116 * Remove a string from the specified tree, freeing the unused nodes.  Returns
117 * true if the string was found/removed.
118 */
119NCURSES_EXPORT(int)
120_nc_remove_string(struct tries **tree, char *string)
121{
122    T((T_CALLED("_nc_remove_string(%p,%s)"), tree, _nc_visbuf(string)));
123
124    if (string == 0 || *string == 0)
125	returnCode(FALSE);
126
127    while (*tree != 0) {
128	if ((unsigned char) (*tree)->ch == (unsigned char) *string) {
129	    if (string[1] != 0)
130		returnCode(_nc_remove_string(&(*tree)->child, string + 1));
131	    if ((*tree)->child) {
132		/* don't cut the whole sub-tree */
133		(*tree)->value = 0;
134	    } else {
135		struct tries *to_free = *tree;
136		*tree = (*tree)->sibling;
137		free(to_free);
138	    }
139	    returnCode(TRUE);
140	}
141	tree = &(*tree)->sibling;
142    }
143    returnCode(FALSE);
144}
145