ncurses 5.0
[ncurses.git] / ncurses / base / tries.c
1 /****************************************************************************
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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
42 MODULE_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  */
48 char *_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  */
83 int _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  */
114 int _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 }