1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
|
/* Copyright (c) 2003-2004, Roger Dingledine
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2019, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file smartlist_foreach.h
* \brief Macros for iterating over the elements of a smartlist_t.
**/
#ifndef TOR_SMARTLIST_FOREACH_H
#define TOR_SMARTLIST_FOREACH_H
/** Iterate over the items in a smartlist <b>sl</b>, in order. For each item,
* assign it to a new local variable of type <b>type</b> named <b>var</b>, and
* execute the statements inside the loop body. Inside the loop, the loop
* index can be accessed as <b>var</b>_sl_idx and the length of the list can
* be accessed as <b>var</b>_sl_len.
*
* NOTE: Do not change the length of the list while the loop is in progress,
* unless you adjust the _sl_len variable correspondingly. See second example
* below.
*
* Example use:
* <pre>
* smartlist_t *list = smartlist_split("A:B:C", ":", 0, 0);
* SMARTLIST_FOREACH_BEGIN(list, char *, cp) {
* printf("%d: %s\n", cp_sl_idx, cp);
* tor_free(cp);
* } SMARTLIST_FOREACH_END(cp);
* smartlist_free(list);
* </pre>
*
* Example use (advanced):
* <pre>
* SMARTLIST_FOREACH_BEGIN(list, char *, cp) {
* if (!strcmp(cp, "junk")) {
* tor_free(cp);
* SMARTLIST_DEL_CURRENT(list, cp);
* }
* } SMARTLIST_FOREACH_END(cp);
* </pre>
*/
/* Note: these macros use token pasting, and reach into smartlist internals.
* This can make them a little daunting. Here's the approximate unpacking of
* the above examples, for entertainment value:
*
* <pre>
* smartlist_t *list = smartlist_split("A:B:C", ":", 0, 0);
* {
* int cp_sl_idx, cp_sl_len = smartlist_len(list);
* char *cp;
* for (cp_sl_idx = 0; cp_sl_idx < cp_sl_len; ++cp_sl_idx) {
* cp = smartlist_get(list, cp_sl_idx);
* printf("%d: %s\n", cp_sl_idx, cp);
* tor_free(cp);
* }
* }
* smartlist_free(list);
* </pre>
*
* <pre>
* {
* int cp_sl_idx, cp_sl_len = smartlist_len(list);
* char *cp;
* for (cp_sl_idx = 0; cp_sl_idx < cp_sl_len; ++cp_sl_idx) {
* cp = smartlist_get(list, cp_sl_idx);
* if (!strcmp(cp, "junk")) {
* tor_free(cp);
* smartlist_del(list, cp_sl_idx);
* --cp_sl_idx;
* --cp_sl_len;
* }
* }
* }
* </pre>
*/
#define SMARTLIST_FOREACH_BEGIN(sl, type, var) \
STMT_BEGIN \
int var ## _sl_idx, var ## _sl_len=(sl)->num_used; \
type var; \
for (var ## _sl_idx = 0; var ## _sl_idx < var ## _sl_len; \
++var ## _sl_idx) { \
var = (sl)->list[var ## _sl_idx];
#define SMARTLIST_FOREACH_END(var) \
var = NULL; \
(void) var ## _sl_idx; \
} STMT_END
/**
* An alias for SMARTLIST_FOREACH_BEGIN and SMARTLIST_FOREACH_END, using
* <b>cmd</b> as the loop body. This wrapper is here for convenience with
* very short loops.
*
* By convention, we do not use this for loops which nest, or for loops over
* 10 lines or so. Use SMARTLIST_FOREACH_{BEGIN,END} for those.
*/
#define SMARTLIST_FOREACH(sl, type, var, cmd) \
SMARTLIST_FOREACH_BEGIN(sl,type,var) { \
cmd; \
} SMARTLIST_FOREACH_END(var)
/** Helper: While in a SMARTLIST_FOREACH loop over the list <b>sl</b> indexed
* with the variable <b>var</b>, remove the current element in a way that
* won't confuse the loop. */
#define SMARTLIST_DEL_CURRENT(sl, var) \
STMT_BEGIN \
smartlist_del(sl, var ## _sl_idx); \
--var ## _sl_idx; \
--var ## _sl_len; \
STMT_END
/** Helper: While in a SMARTLIST_FOREACH loop over the list <b>sl</b> indexed
* with the variable <b>var</b>, remove the current element in a way that
* won't confuse the loop. */
#define SMARTLIST_DEL_CURRENT_KEEPORDER(sl, var) \
STMT_BEGIN \
smartlist_del_keeporder(sl, var ## _sl_idx); \
--var ## _sl_idx; \
--var ## _sl_len; \
STMT_END
/** Helper: While in a SMARTLIST_FOREACH loop over the list <b>sl</b> indexed
* with the variable <b>var</b>, replace the current element with <b>val</b>.
* Does not deallocate the current value of <b>var</b>.
*/
#define SMARTLIST_REPLACE_CURRENT(sl, var, val) \
STMT_BEGIN \
smartlist_set(sl, var ## _sl_idx, val); \
STMT_END
#endif /* !defined(TOR_SMARTLIST_FOREACH_H) */
|
