vectorscan/src/nfa/castle_internal.h

/*
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 * Copyright (c) 2021, Arm Limited
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/** \file
 * \brief Castle: multi-tenant repeat engine, data structures.
 */

#ifndef NFA_CASTLE_INTERNAL_H
#define NFA_CASTLE_INTERNAL_H

#include "ue2common.h"
#include "repeat_internal.h"

struct SubCastle {
    ReportID report;        //!< report to raise on match
    u32 fullStateOffset;    //!< offset within full state (scratch)
    u32 streamStateOffset;  //!< offset within stream state
    u32 repeatInfoOffset;   //!< offset of RepeatInfo structure
                            //   relative to the start of SubCastle
    u32 exclusiveId;        //!< exclusive group id of this SubCastle,
                            //   set to the number of SubCastles in Castle
                            //   if it is not exclusive
};

#define CASTLE_DOT 0
#define CASTLE_VERM 1
#define CASTLE_NVERM 2
#define CASTLE_SHUFTI 3
#define CASTLE_TRUFFLE 4
#define CASTLE_VERM16 5
#define CASTLE_NVERM16 6

enum ExclusiveType {
    NOT_EXCLUSIVE,     //!< no subcastles are exclusive
    EXCLUSIVE,         //!< a subset of subcastles are exclusive
    PURE_EXCLUSIVE     //!< all subcastles are exclusive
};

/**
 * \brief Castle engine structure.
 *
 * A Castle is a collection of repeats that all share the same character
 * reachability.
 *
 * The whole engine is laid out in memory as:
 *
 * - struct NFA
 * - struct Castle
 * - struct SubCastle[numRepeats]
 * - tables for sparse model repeats
 * - sparse iterator for subcastles that may be stale
 *
 * Castle stores an "active repeats" multibit in stream state, followed by the
 * packed repeat state for each SubCastle. If there are both exclusive and
 * non-exclusive SubCastle groups, we use an active id for each exclusive group
 * and a multibit for the non-exclusive group. We also store an "active
 * exclusive groups" multibit for exclusive groups. If all SubCastles are mutual
 * exclusive, we remove "active repeats" multibit from stream state.
 * * Castle stream state:
 * *
 * * |---|
 * * |   | active subengine id for exclusive group 1
 * * |---|
 * * |   | active subengine id for exclusive group 2(if necessary)
 * * |---|
 * * ...
 * * |---|
 * * |   | "active repeats" multibit for non-exclusive subcastles
 * * |   | (if not all subcastles are exclusive)
 * * |---|
 * * |   | active multibit for exclusive groups
 * * |   |
 * * |---|
 * * ||-|| common pool of stream state for exclusive group 1
 * * ||-||
 * * |---|
 * * ||-|| common pool of stream state for exclusive group 2(if necessary)
 * * ||-||
 * * |---|
 * * ...
 * * |---|
 * * |   | stream state for each non-exclusive subcastles
 * * ...
 * * |   |
 * * |---|
 *
 * In full state (stored in scratch space) it stores a temporary multibit over
 * the repeats (used by \ref castleMatchLoop), followed by the repeat control
 * blocks for each SubCastle.
 */
struct ALIGN_AVX_DIRECTIVE Castle {
    u32 numRepeats;         //!< number of repeats in Castle
    u32 numGroups;          //!< number of exclusive groups
    u8 type;                //!< tells us which scanning mechanism (below) to use
    u8 exclusive;           //!< tells us if there are mutual exclusive SubCastles
    u8 activeIdxSize;       //!< number of bytes in stream state to store
                            // active SubCastle id for exclusive mode
    u32 activeOffset;       //!< offset to active multibit for non-exclusive
                            // SubCastles
    u32 staleIterOffset;    //!< offset to a sparse iterator to check for stale
                            // sub castles
    u32 groupIterOffset;    //!< offset to a iterator to check the aliveness of
                            // exclusive groups

    union {
        struct {
            char c;
        } verm;
        struct {
            m128 mask;
        } verm16;
        struct {
            m128 mask_lo;
            m128 mask_hi;
        } shuf;
        struct {
            m128 mask1;
            m128 mask2;
        } truffle;
    } u;
};

#endif // NFA_CASTLE_INTERNAL_H