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 * Copyright (c) 2015, Intel Corporation
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/** \file
 * \brief NFA Callback definitions, used at runtime.
 */

#ifndef NFA_CALLBACK_H
#define NFA_CALLBACK_H

#include "ue2common.h"

/** \brief The type for an NFA callback.
 *
 * This is a function that takes as arguments the current offset where the
 * match occurs, the id of the match and the context pointer that was passed
 * into the NFA API function that executed the NFA.
 *
 * The offset where the match occurs will be the offset after the character
 * that caused the match. Thus, if we have a buffer containing 'abc', then a
 * pattern that matches an empty string will have an offset of 0, a pattern
 * that matches 'a' will have an offset of 1, and a pattern that matches 'abc'
 * will have an offset of 3, which will be a value that is 'beyond' the size of
 * the buffer. That is, if we have n characters in the buffer, there are n+1
 * different potential offsets for matches.
 *
 * This function should return an int - currently the possible return values
 * are 0, which means 'stop running the engine' or non-zero, which means
 * 'continue matching'.
 */
typedef int (*NfaCallback)(u64a offset, ReportID id, void *context);

/** \brief The type for an NFA callback which also tracks start of match.
 *
 * see \ref NfaCallback
 */
typedef int (*SomNfaCallback)(u64a from_offset, u64a to_offset, ReportID id,
                              void *context);

/**
 * standard \ref NfaCallback return value indicating that engine execution
 * should continue. (any non-zero value will serve this purpose)
 */
#define MO_CONTINUE_MATCHING 1

/**
 * \ref NfaCallback return value indicating that engine execution should halt.
 */
#define MO_HALT_MATCHING 0

#endif // NFA_CALLBACK_H