Time offset: use trace offset average
[babeltrace.git] / include / babeltrace / iterator.h
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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
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23/* Forward declarations */
24struct babeltrace_iter;
25struct ctf_stream_event;
26struct ctf_stream;
27struct babeltrace_saved_pos;
28
29struct trace_collection_pos {
30 enum {
31 BT_SEEK_TIME, /* uses u.seek_time */
32 BT_SEEK_RESTORE, /* uses u.restore */
33 BT_SEEK_CUR,
34 BT_SEEK_BEGIN,
35 BT_SEEK_END,
36 } type;
37 union {
38 uint64_t seek_time;
39 struct babeltrace_saved_pos *restore;
40 } u;
41};
42
43/*
44 * babeltrace_iter_create - Allocate a trace collection iterator.
45 *
46 * begin_pos and end_pos are optional parameters to specify the position
47 * at which the trace collection should be seeked upon iterator
48 * creation, and the position at which iteration will start returning
49 * "EOF".
50 *
51 * By default, if begin_pos is NULL, a BT_SEEK_CUR is performed at
52 * creation. By default, if end_pos is NULL, a BT_SEEK_END (end of
53 * trace) is the EOF criterion.
54 */
55struct babeltrace_iter *babeltrace_iter_create(struct bt_context *ctx,
56 struct trace_collection_pos *begin_pos,
57 struct trace_collection_pos *end_pos);
58
59/*
60 * babeltrace_iter_destroy - Free a trace collection iterator.
61 */
62void babeltrace_iter_destroy(struct babeltrace_iter *iter);
63
64/*
65 * babeltrace_iter_next: Move trace collection position to the next event.
66 *
67 * Returns 0 on success, a negative value on error
68 */
69int babeltrace_iter_next(struct babeltrace_iter *iter);
70
71/*
72 * babeltrace_iter_save_pos - Save the current trace collection position.
73 *
74 * The position returned by this function needs to be freed by
75 * babeltrace_iter_free_pos after use.
76 */
77struct trace_collection_pos *
78 babeltrace_iter_save_pos(struct babeltrace_iter *iter);
79
80/*
81 * babeltrace_iter_free_pos - Free the position.
82 */
83void babeltrace_iter_free_pos(struct trace_collection_pos *pos);
84
85/*
86 * babeltrace_iter_seek: seek iterator to given position.
87 *
88 * Return EOF if position is after the last event of the trace collection.
89 * Return other negative value for other errors.
90 * Return 0 for success.
91 */
92int babeltrace_iter_seek(struct babeltrace_iter *iter,
93 const struct trace_collection_pos *pos);
94
95/*
96 * babeltrace_iter_read_event: Read the iterator's current event data.
97 *
98 * @iter: trace collection iterator (input)
99 * @stream: stream containing event at current position (output)
100 * @event: current event (output)
101 * Return 0 on success, negative error value on error.
102 */
103int babeltrace_iter_read_event(struct babeltrace_iter *iter,
104 struct ctf_stream **stream,
105 struct ctf_stream_event **event);
106
107#endif /* _BABELTRACE_ITERATOR_H */
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