stem.h

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/* Copyright (C) 2005-2026 Olly Betts
 * Copyright (C) 2010 Evgeny Sizikov
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see
 * <https://www.gnu.org/licenses/>.
 */
 
#ifndef XAPIAN_INCLUDED_STEM_H
#define XAPIAN_INCLUDED_STEM_H
 
#if !defined XAPIAN_IN_XAPIAN_H && !defined XAPIAN_LIB_BUILD
# error Never use <xapian/stem.h> directly; include <xapian.h> instead.
#endif
 
#include <xapian/constinfo.h>
#include <xapian/intrusive_ptr.h>
#include <xapian/visibility.h>
 
#include <string>
#include <string_view>
 
namespace Xapian {
 
class XAPIAN_VISIBILITY_DEFAULT StemImplementation
    : public Xapian::Internal::intrusive_base
{
    void operator=(const StemImplementation &) = delete;
 
    StemImplementation(const StemImplementation &) = delete;
 
  public:
    StemImplementation() { }
 
    virtual ~StemImplementation();
 
    virtual std::string operator()(const std::string & word) = 0;
 
    virtual bool use_proper_noun_heuristic() const;
 
    virtual std::string get_description() const = 0;
};
 
class XAPIAN_VISIBILITY_DEFAULT Stem {
  public:
    Xapian::Internal::intrusive_ptr<StemImplementation> internal;
 
    Stem(const Stem& o) : internal(o.internal) { }
 
    Stem& operator=(const Stem& o) {
        internal = o.internal;
        return *this;
    }
 
    Stem(Stem&&) = default;
 
    Stem& operator=(Stem&&) = default;
 
    Stem() { }
 
    Stem(std::string_view language, bool fallback = false);
 
    explicit Stem(StemImplementation* p) : internal(p) { }
 
    ~Stem() { }
 
    std::string operator()(const std::string& word) const {
        if (!internal || word.empty()) return word;
        return internal->operator()(word);
    }
 
    bool is_none() const { return !internal; }
 
    std::string get_description() const;
 
    static std::string get_available_languages() {
        const struct Xapian::Internal::constinfo * info =
            Xapian::Internal::get_constinfo_();
        return std::string(info->stemmer_data, info->stemmer_name_len);
    }
};
 
}
 
#endif // XAPIAN_INCLUDED_STEM_H