API : Access CTF events fields
[babeltrace.git] / include / babeltrace / iterator.h
1 #ifndef _BABELTRACE_ITERATOR_H
2 #define _BABELTRACE_ITERATOR_H
3
4 /*
5 * BabelTrace API Iterators
6 *
7 * Copyright 2010-2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
8 *
9 * Permission is hereby granted, free of charge, to any person obtaining a copy
10 * of this software and associated documentation files (the "Software"), to deal
11 * in the Software without restriction, including without limitation the rights
12 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
13 * copies of the Software, and to permit persons to whom the Software is
14 * furnished to do so, subject to the following conditions:
15 *
16 * The above copyright notice and this permission notice shall be included in
17 * all copies or substantial portions of the Software.
18 */
19
20 #include <babeltrace/format.h>
21 #include <babeltrace/context.h>
22 #include <babeltrace/ctf/events.h>
23
24 /* Forward declarations */
25 struct bt_iter;
26 struct ctf_stream_event;
27 struct ctf_stream;
28 struct bt_saved_pos;
29
30 struct bt_iter_pos {
31 enum {
32 BT_SEEK_TIME, /* uses u.seek_time */
33 BT_SEEK_RESTORE, /* uses u.restore */
34 BT_SEEK_CUR,
35 BT_SEEK_BEGIN,
36 BT_SEEK_END,
37 } type;
38 union {
39 uint64_t seek_time;
40 struct bt_saved_pos *restore;
41 } u;
42 };
43
44 /*
45 * bt_iter_create - Allocate a trace collection iterator.
46 *
47 * begin_pos and end_pos are optional parameters to specify the position
48 * at which the trace collection should be seeked upon iterator
49 * creation, and the position at which iteration will start returning
50 * "EOF".
51 *
52 * By default, if begin_pos is NULL, a BT_SEEK_CUR is performed at
53 * creation. By default, if end_pos is NULL, a BT_SEEK_END (end of
54 * trace) is the EOF criterion.
55 */
56 struct bt_iter *bt_iter_create(struct bt_context *ctx,
57 struct bt_iter_pos *begin_pos,
58 struct bt_iter_pos *end_pos);
59
60 /*
61 * bt_iter_destroy - Free a trace collection iterator.
62 */
63 void bt_iter_destroy(struct bt_iter *iter);
64
65 /*
66 * bt_iter_next: Move trace collection position to the next event.
67 *
68 * Returns 0 on success, a negative value on error
69 */
70 int bt_iter_next(struct bt_iter *iter);
71
72 /*
73 * bt_iter_get_pos - Get the current iterator position.
74 *
75 * The position returned by this function needs to be freed by
76 * bt_iter_free_pos after use.
77 */
78 struct bt_iter_pos *
79 bt_iter_get_pos(struct bt_iter *iter);
80
81 /*
82 * bt_iter_free_pos - Free the position.
83 */
84 void bt_iter_free_pos(struct bt_iter_pos *pos);
85
86 /*
87 * bt_iter_set_pos: move the iterator to a given position.
88 *
89 * On error, the stream_heap is reinitialized and returned empty.
90 *
91 * Return 0 for success.
92 *
93 * Return EOF if the position requested is after the last event of the
94 * trace collection.
95 * Return -EINVAL when called with invalid parameter.
96 * Return -ENOMEM if the stream_heap could not be properly initialized.
97 */
98 int bt_iter_set_pos(struct bt_iter *iter, const struct bt_iter_pos *pos);
99
100 /*
101 * bt_iter_create_time_pos: create a position based on time
102 *
103 * This function allocates and returns a new bt_iter_pos (which must be freed
104 * with bt_iter_free_pos) to be able to restore an iterator position based on a
105 * timestamp.
106 */
107 struct bt_iter_pos *bt_iter_create_time_pos(struct bt_iter *iter,
108 uint64_t timestamp);
109
110 /*
111 * bt_iter_read_ctf_event: Read the iterator's current event data.
112 *
113 * @iter: trace collection iterator (input)
114 * @stream: stream containing event at current position (output)
115 * @event: current event (output)
116 * Return 0 on success, negative error value on error.
117 */
118 struct bt_ctf_event *bt_iter_read_ctf_event(struct bt_iter *iter);
119
120 #endif /* _BABELTRACE_ITERATOR_H */
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