path: root/contrib/libs/hyperscan/src/util/ue2string.h

/*
 * Copyright (c) 2015-2019, Intel Corporation
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  * Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *  * Neither the name of Intel Corporation nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/** \file
 * \brief Tools for string manipulation, ue2_literal definition.
 */

#ifndef UE2STRING_H
#define UE2STRING_H

#include "ue2common.h"
#include "util/charreach.h"
#include "util/compare.h" 
#include "util/hash.h" 
#include "util/operators.h" 

#include <iterator>
#include <string>
#include <vector>

#include <boost/dynamic_bitset.hpp> 
#include <boost/iterator/iterator_facade.hpp>

namespace ue2 {

/// Force the given string to upper-case.
void upperString(std::string &s);

size_t maxStringOverlap(const std::string &a, const std::string &b,
                        bool nocase);

size_t maxStringSelfOverlap(const std::string &a, bool nocase);

/// Compares two strings, returns non-zero if they're different.
u32 cmp(const char *a, const char *b, size_t len, bool nocase);

/** 
 * \brief String type that also records whether the whole string is caseful or 
 * caseless. 
 * 
 * You should use \ref ue2_literal if you need to represent a mixed-case 
 * literal. 
 */ 
struct ue2_case_string { 
    ue2_case_string(std::string s_in, bool nocase_in) 
        : s(std::move(s_in)), nocase(nocase_in) { 
        if (nocase) { 
            upperString(s); 
        } 
    } 

    bool operator==(const ue2_case_string &other) const { 
        return s == other.s && nocase == other.nocase; 
    } 
 
    std::string s; 
    bool nocase; 
}; 
 
struct ue2_literal : totally_ordered<ue2_literal> { 
public:
    /// Single element proxy, pointed to by our const_iterator.
    struct elem {
        elem() : c(0), nocase(false) {}
        elem(char c_in, bool nc_in) : c(c_in), nocase(nc_in) {}
        bool operator==(const elem &o) const {
            return c == o.c && nocase == o.nocase;
        }
        bool operator!=(const elem &o) const {
            return c != o.c || nocase != o.nocase;
        }
        operator CharReach() const;
        char c;
        bool nocase;
    };

    /// Boost iterator_facade lets us synthesize an iterator simply.
    class const_iterator : public boost::iterator_facade<
            const_iterator,
            elem const,
            boost::random_access_traversal_tag,
            elem const> {
    public:
        const_iterator() {}
    private:
        friend class boost::iterator_core_access;
        void increment() {
            ++idx; 
        }
        void decrement() {
            --idx; 
        }
        void advance(size_t n) {
            idx += n; 
        }
        difference_type distance_to(const const_iterator &other) const {
            return other.idx - idx; 
        }
        bool equal(const const_iterator &other) const {
            return idx == other.idx && lit == other.lit; 
        }
        const elem dereference() const {
            return elem(lit->s[idx], lit->nocase[idx]); 
        }

        friend struct ue2_literal;
        const_iterator(const ue2_literal &lit_in, size_t idx_in) 
            : lit(&lit_in), idx(idx_in) {} 

        const ue2_literal *lit = nullptr; 
        size_t idx; 
    };

    using const_reverse_iterator = std::reverse_iterator<const_iterator>;
    using size_type = std::string::size_type; 

    static const size_type npos; 

    ue2_literal() = default; 
    ue2_literal(const std::string &s_in, bool nc_in);
    ue2_literal(char c, bool nc_in);
    ue2_literal(const ue2_literal &) = default;
    ue2_literal(ue2_literal &&) = default;
    ue2_literal &operator=(const ue2_literal &) = default;
    ue2_literal &operator=(ue2_literal &&) = default;

    template<typename InputIt> 
    ue2_literal(InputIt b, InputIt e) { 
        for (; b != e; ++b) { 
            push_back(*b); 
        } 
    } 
 
    size_type length() const { return s.length(); }
    bool empty() const { return s.empty(); }
    ue2_literal substr(size_type pos, size_type n = npos) const; 
    const char *c_str() const { return s.c_str(); }
    bool any_nocase() const;

    const_iterator begin() const {
        return const_iterator(*this, 0); 
    }

    const_iterator end() const {
        return const_iterator(*this, s.size()); 
    }

    const_reverse_iterator rbegin() const {
        return const_reverse_iterator(end());
    }

    const_reverse_iterator rend() const {
        return const_reverse_iterator(begin());
    }

    ue2_literal &erase(size_type pos = 0, size_type n = npos); 
    void push_back(const elem &e) {
        push_back(e.c, e.nocase);
    }

    void push_back(char c, bool nc);
    const elem back() const { return *rbegin(); } 

    friend ue2_literal operator+(ue2_literal a, const ue2_literal &b) { 
        a += b; 
        return a; 
    } 
 
    /// Reverse this literal in-place. 
    void reverse(); 
 
    void operator+=(const ue2_literal &b);
    bool operator==(const ue2_literal &b) const {
        return s == b.s && nocase == b.nocase;
    }
    bool operator<(const ue2_literal &b) const;

    void clear(void) { s.clear(); nocase.clear(); }

    const std::string &get_string() const { return s; }

    void swap(ue2_literal &other) {
        s.swap(other.s);
        nocase.swap(other.nocase);
    }

    size_t hash() const; 
 
private:
    friend const_iterator; 
    std::string s;
    boost::dynamic_bitset<> nocase; 
};

/// Return a reversed copy of this literal.
ue2_literal reverse_literal(const ue2_literal &in);

// Escape any meta characters in a string
std::string escapeStringMeta(const std::string &s);

/** Note: may be overly conservative if only partially nocase */
size_t maxStringSelfOverlap(const ue2_literal &a);
size_t minStringPeriod(const ue2_literal &a);
size_t maxStringOverlap(const ue2_literal &a, const ue2_literal &b);

/** 
 * \brief True iff the range of a literal given cannot be considered entirely 
 * case-sensitive nor entirely case-insensitive. 
 */ 
template<class Iter> 
bool mixed_sensitivity_in(Iter begin, Iter end) { 
    bool cs = false; 
    bool nc = false; 
    for (auto it = begin; it != end; ++it) { 
        if (!ourisalpha(it->c)) { 
            continue; 
        } 
        if (it->nocase) { 
            nc = true; 
        } else { 
            cs = true; 
        } 
    } 

    return cs && nc; 
} 
 
/** 
 * \brief True iff the literal cannot be considered entirely case-sensitive 
 * nor entirely case-insensitive. 
 */ 
inline 
bool mixed_sensitivity(const ue2_literal &s) { 
    return mixed_sensitivity_in(s.begin(), s.end()); 
} 
 
void make_nocase(ue2_literal *lit);

struct case_iter {
    explicit case_iter(const ue2_literal &ss);
    const std::string &operator*() const { return s; } /* limited lifetime */
    case_iter &operator++ ();
    bool operator!=(const case_iter &b) const { return s != b.s; }
private:
    std::string s;
    std::string s_orig;
    std::vector<bool> nocase;
};

case_iter caseIterateBegin(const ue2_literal &lit);
case_iter caseIterateEnd();

/** \brief True if there is any overlap between the characters in \a s and the
 * set characters in \a cr.
 *
 * Note: this means that if \a s is nocase, then \a cr only needs to have
 * either the lower-case or upper-case version of a letter set.  */
bool contains(const ue2_literal &s, const CharReach &cr);

/// Returns true if \a a is a suffix of (or equal to) \a b.
bool isSuffix(const ue2_literal &a, const ue2_literal &b);

static inline
std::vector<CharReach> as_cr_seq(const ue2_literal &s) {
    std::vector<CharReach> rv;
    rv.reserve(s.length());
    rv.insert(rv.end(), s.begin(), s.end());
    return rv;
}

/** \brief True if the given literal consists entirely of a flood of the same
 * character. */
bool is_flood(const ue2_literal &s);

#if defined(DUMP_SUPPORT) || defined(DEBUG)
/* Utility functions for debugging/dumping */

/// Escape a string so it's dot-printable.
std::string dotEscapeString(const std::string &s);

std::string dumpString(const ue2_literal &lit);

/// Escape a string so that it's screen-printable.
std::string escapeString(const std::string &s);

/// Escape a ue2_literal so that it's screen-printable.
std::string escapeString(const ue2_literal &lit);

#endif

} // namespace ue2

namespace std { 
 
template<> 
struct hash<ue2::ue2_literal::elem> { 
    size_t operator()(const ue2::ue2_literal::elem &elem) const { 
        return ue2::hash_all(elem.c, elem.nocase); 
    } 
}; 
 
template<> 
struct hash<ue2::ue2_literal> { 
    size_t operator()(const ue2::ue2_literal &lit) const { 
        return lit.hash(); 
    } 
}; 
 
} // namespace std 
 
#endif