1/*
2 * Copyright (c) 2015-2016, Intel Corporation
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27 */
28
29/** \file
30 * \brief NFA Callback definitions, used at runtime.
31 */
32
33#ifndef NFA_CALLBACK_H
34#define NFA_CALLBACK_H
35
36#include "ue2common.h"
37
38/** \brief The type for an NFA callback.
39 *
40 * This is a function that takes as arguments the current start and end offsets
41 * where the match occurs, the id of the match and the context pointer that was
42 * passed into the NFA API function that executed the NFA.
43 *
44 * The start offset is the "start of match" (SOM) offset for the match. It is
45 * only provided by engines that natively support SOM tracking (e.g. Gough).
46 *
47 * The end offset will be the offset after the character that caused the match.
48 * Thus, if we have a buffer containing 'abc', then a pattern that matches an
49 * empty string will have an offset of 0, a pattern that matches 'a' will have
50 * an offset of 1, and a pattern that matches 'abc' will have an offset of 3,
51 * which will be a value that is 'beyond' the size of the buffer. That is, if
52 * we have n characters in the buffer, there are n+1 different potential
53 * offsets for matches.
54 *
55 * This function should return an int - currently the possible return values
56 * are 0, which means 'stop running the engine' or non-zero, which means
57 * 'continue matching'.
58 */
59typedef int (*NfaCallback)(u64a start, u64a end, ReportID id, void *context);
60
61/**
62 * standard \ref NfaCallback return value indicating that engine execution
63 * should continue. (any non-zero value will serve this purpose)
64 */
65#define MO_CONTINUE_MATCHING 1
66
67/**
68 * \ref NfaCallback return value indicating that engine execution should halt.
69 */
70#define MO_HALT_MATCHING 0
71
72#endif // NFA_CALLBACK_H
73