Fix callback.h documentation
[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
6204d33c 23/* Forward declarations */
e8c92a62 24struct bt_iter;
e8c92a62 25struct bt_saved_pos;
6204d33c 26
e8c92a62 27struct bt_iter_pos {
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28 enum {
29 BT_SEEK_TIME, /* uses u.seek_time */
30 BT_SEEK_RESTORE, /* uses u.restore */
31 BT_SEEK_CUR,
32 BT_SEEK_BEGIN,
33 BT_SEEK_END,
34 } type;
35 union {
36 uint64_t seek_time;
e8c92a62 37 struct bt_saved_pos *restore;
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38 } u;
39};
40
41/*
e8c92a62 42 * bt_iter_create - Allocate a trace collection iterator.
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43 *
44 * begin_pos and end_pos are optional parameters to specify the position
45 * at which the trace collection should be seeked upon iterator
46 * creation, and the position at which iteration will start returning
47 * "EOF".
48 *
49 * By default, if begin_pos is NULL, a BT_SEEK_CUR is performed at
50 * creation. By default, if end_pos is NULL, a BT_SEEK_END (end of
51 * trace) is the EOF criterion.
52 */
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53struct bt_iter *bt_iter_create(struct bt_context *ctx,
54 struct bt_iter_pos *begin_pos,
55 struct bt_iter_pos *end_pos);
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56
57/*
e8c92a62 58 * bt_iter_destroy - Free a trace collection iterator.
6204d33c 59 */
e8c92a62 60void bt_iter_destroy(struct bt_iter *iter);
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61
62/*
e8c92a62 63 * bt_iter_next: Move trace collection position to the next event.
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64 *
65 * Returns 0 on success, a negative value on error
66 */
e8c92a62 67int bt_iter_next(struct bt_iter *iter);
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68
69/*
90fcbacc 70 * bt_iter_get_pos - Get the current iterator position.
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71 *
72 * The position returned by this function needs to be freed by
e8c92a62 73 * bt_iter_free_pos after use.
6204d33c 74 */
e8c92a62 75struct bt_iter_pos *
90fcbacc 76 bt_iter_get_pos(struct bt_iter *iter);
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77
78/*
e8c92a62 79 * bt_iter_free_pos - Free the position.
6204d33c 80 */
e8c92a62 81void bt_iter_free_pos(struct bt_iter_pos *pos);
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82
83/*
90fcbacc 84 * bt_iter_set_pos: move the iterator to a given position.
6204d33c 85 *
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86 * On error, the stream_heap is reinitialized and returned empty.
87 *
6204d33c 88 * Return 0 for success.
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89 *
90 * Return EOF if the position requested is after the last event of the
91 * trace collection.
92 * Return -EINVAL when called with invalid parameter.
93 * Return -ENOMEM if the stream_heap could not be properly initialized.
94 */
95int bt_iter_set_pos(struct bt_iter *iter, const struct bt_iter_pos *pos);
96
97/*
98 * bt_iter_create_time_pos: create a position based on time
99 *
100 * This function allocates and returns a new bt_iter_pos (which must be freed
101 * with bt_iter_free_pos) to be able to restore an iterator position based on a
102 * timestamp.
6204d33c 103 */
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104struct bt_iter_pos *bt_iter_create_time_pos(struct bt_iter *iter,
105 uint64_t timestamp);
6204d33c 106
6204d33c 107#endif /* _BABELTRACE_ITERATOR_H */
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