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1 | /* list.c - Functions for manipulating linked lists of objects. */ | |
2 | ||
3 | /* Copyright (C) 1996-2009 Free Software Foundation, Inc. | |
4 | ||
5 | This file is part of GNU Bash, the Bourne Again SHell. | |
6 | ||
7 | Bash is free software: you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation, either version 3 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | Bash is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with Bash. If not, see <http://www.gnu.org/licenses/>. | |
19 | */ | |
20 | ||
21 | #include "config.h" | |
22 | ||
23 | #if defined (HAVE_UNISTD_H) | |
24 | # ifdef _MINIX | |
25 | # include <sys/types.h> | |
26 | # endif | |
27 | # include <unistd.h> | |
28 | #endif | |
29 | ||
30 | #include "shell.h" | |
31 | ||
32 | /* A global variable which acts as a sentinel for an `error' list return. */ | |
33 | GENERIC_LIST global_error_list; | |
34 | ||
35 | #ifdef INCLUDE_UNUSED | |
36 | /* Call FUNCTION on every member of LIST, a generic list. */ | |
37 | void | |
38 | list_walk (list, function) | |
39 | GENERIC_LIST *list; | |
40 | sh_glist_func_t *function; | |
41 | { | |
42 | for ( ; list; list = list->next) | |
43 | if ((*function) (list) < 0) | |
44 | return; | |
45 | } | |
46 | ||
47 | /* Call FUNCTION on every string in WORDS. */ | |
48 | void | |
49 | wlist_walk (words, function) | |
50 | WORD_LIST *words; | |
51 | sh_icpfunc_t *function; | |
52 | { | |
53 | for ( ; words; words = words->next) | |
54 | if ((*function) (words->word->word) < 0) | |
55 | return; | |
56 | } | |
57 | #endif /* INCLUDE_UNUSED */ | |
58 | ||
59 | /* Reverse the chain of structures in LIST. Output the new head | |
60 | of the chain. You should always assign the output value of this | |
61 | function to something, or you will lose the chain. */ | |
62 | GENERIC_LIST * | |
63 | list_reverse (list) | |
64 | GENERIC_LIST *list; | |
65 | { | |
66 | register GENERIC_LIST *next, *prev; | |
67 | ||
68 | for (prev = (GENERIC_LIST *)NULL; list; ) | |
69 | { | |
70 | next = list->next; | |
71 | list->next = prev; | |
72 | prev = list; | |
73 | list = next; | |
74 | } | |
75 | return (prev); | |
76 | } | |
77 | ||
78 | /* Return the number of elements in LIST, a generic list. */ | |
79 | int | |
80 | list_length (list) | |
81 | GENERIC_LIST *list; | |
82 | { | |
83 | register int i; | |
84 | ||
85 | for (i = 0; list; list = list->next, i++); | |
86 | return (i); | |
87 | } | |
88 | ||
89 | /* Append TAIL to HEAD. Return the header of the list. */ | |
90 | GENERIC_LIST * | |
91 | list_append (head, tail) | |
92 | GENERIC_LIST *head, *tail; | |
93 | { | |
94 | register GENERIC_LIST *t_head; | |
95 | ||
96 | if (head == 0) | |
97 | return (tail); | |
98 | ||
99 | for (t_head = head; t_head->next; t_head = t_head->next) | |
100 | ; | |
101 | t_head->next = tail; | |
102 | return (head); | |
103 | } | |
104 | ||
105 | #ifdef INCLUDE_UNUSED | |
106 | /* Delete the element of LIST which satisfies the predicate function COMPARER. | |
107 | Returns the element that was deleted, so you can dispose of it, or -1 if | |
108 | the element wasn't found. COMPARER is called with the list element and | |
109 | then ARG. Note that LIST contains the address of a variable which points | |
110 | to the list. You might call this function like this: | |
111 | ||
112 | SHELL_VAR *elt = list_remove (&variable_list, check_var_has_name, "foo"); | |
113 | dispose_variable (elt); | |
114 | */ | |
115 | GENERIC_LIST * | |
116 | list_remove (list, comparer, arg) | |
117 | GENERIC_LIST **list; | |
118 | Function *comparer; | |
119 | char *arg; | |
120 | { | |
121 | register GENERIC_LIST *prev, *temp; | |
122 | ||
123 | for (prev = (GENERIC_LIST *)NULL, temp = *list; temp; prev = temp, temp = temp->next) | |
124 | { | |
125 | if ((*comparer) (temp, arg)) | |
126 | { | |
127 | if (prev) | |
128 | prev->next = temp->next; | |
129 | else | |
130 | *list = temp->next; | |
131 | return (temp); | |
132 | } | |
133 | } | |
134 | return ((GENERIC_LIST *)&global_error_list); | |
135 | } | |
136 | #endif |