structure.h

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/*
 *  GiNaC Copyright (C) 1999-2026 Johannes Gutenberg University Mainz, Germany
 *
 *  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 GINAC_STRUCTURE_H
#define GINAC_STRUCTURE_H
 
#include "ex.h"
#include "ncmul.h"
#include "numeric.h"
#include "operators.h"
#include "print.h"
 
#include <functional>
 
namespace GiNaC {
 
template <class T>
class compare_all_equal {
protected:
    static bool struct_is_equal(const T * t1, const T * t2) { return true; }
    static int struct_compare(const T * t1, const T * t2) { return 0; }
 
    // disallow destruction of structure through a compare_all_equal*
protected:
    ~compare_all_equal() {}
};
 
 
template <class T>
class compare_std_less {
protected:
    static bool struct_is_equal(const T * t1, const T * t2)
    {
        return std::equal_to<T>()(*t1, *t2);
    }
 
    static int struct_compare(const T * t1, const T * t2)
    {
        if (std::less<T>()(*t1, *t2))
            return -1;
        else if (std::less<T>()(*t2, *t1))
            return 1;
        else
            return 0;
    }
 
    // disallow destruction of structure through a compare_std_less*
protected:
    ~compare_std_less() {}
};
 
 
template <class T>
class compare_bitwise {
protected:
    static bool struct_is_equal(const T * t1, const T * t2)
    {
        const char * cp1 = reinterpret_cast<const char *>(t1);
        const char * cp2 = reinterpret_cast<const char *>(t2);
 
        return std::equal(cp1, cp1 + sizeof(T), cp2);
    }
 
    static int struct_compare(const T * t1, const T * t2)
    {
        const unsigned char * cp1 = reinterpret_cast<const unsigned char *>(t1);
        const unsigned char * cp2 = reinterpret_cast<const unsigned char *>(t2);
        typedef std::pair<const unsigned char *, const unsigned char *> cppair;
 
        cppair res = std::mismatch(cp1, cp1 + sizeof(T), cp2);
 
        if (res.first == cp1 + sizeof(T))
            return 0;
        else if (*res.first < *res.second)
            return -1;
        else
            return 1;
    }
 
    // disallow destruction of structure through a compare_bitwise*
protected:
    ~compare_bitwise() {}
};
 
 
// Select default comparison policy
template <class T, template <class> class ComparisonPolicy = compare_all_equal> class structure;
 
 
template <class T, template <class> class ComparisonPolicy>
class structure : public basic, public ComparisonPolicy<T> {
    GINAC_DECLARE_REGISTERED_CLASS(structure, basic)
 
    // helpers
    static const char *get_class_name() { return "structure"; }
    // constructors
public:
    structure(const T & t) : obj(t) { }
 
    // functions overriding virtual functions from base classes
    // All these are just defaults that can be specialized by the user
public:
    // evaluation
    ex eval() const override { return hold(); }
    ex evalm() const override { return inherited::evalm(); }
protected:
    ex eval_ncmul(const exvector & v) const override { return hold_ncmul(v); }
public:
    ex eval_indexed(const basic & i) const override { return i.hold(); }
 
    // printing
    void print(const print_context & c, unsigned level = 0) const override { inherited::print(c, level); }
    unsigned precedence() const override { return 70; }
 
    // info
    bool info(unsigned inf) const override { return false; }
 
    // operand access
    size_t nops() const override { return 0; }
    ex op(size_t i) const override { return inherited::op(i); }
    ex operator[](const ex & index) const override { return inherited::operator[](index); }
    ex operator[](size_t i) const override { return inherited::operator[](i); }
    ex & let_op(size_t i) override { return inherited::let_op(i); }
    ex & operator[](const ex & index) override { return inherited::operator[](index); }
    ex & operator[](size_t i) override { return inherited::operator[](i); }
 
    // pattern matching
    bool has(const ex & other, unsigned options = 0) const override { return inherited::has(other, options); }
    bool match(const ex & pattern, exmap& repl_lst) const override { return inherited::match(pattern, repl_lst); }
protected:
    bool match_same_type(const basic & other) const override { return true; }
public:
 
    // substitutions
    ex subs(const exmap & m, unsigned options = 0) const override { return inherited::subs(m, options); }
 
    // function mapping
    ex map(map_function & f) const override { return inherited::map(f); }
 
    // degree/coeff
    int degree(const ex & s) const override { return inherited::degree(s); }
    int ldegree(const ex & s) const override { return inherited::ldegree(s); }
    ex coeff(const ex & s, int n = 1) const override { return inherited::coeff(s, n); }
 
    // expand/collect
    ex expand(unsigned options = 0) const override { return inherited::expand(options); }
    ex collect(const ex & s, bool distributed = false) const override { return inherited::collect(s, distributed); }
 
    // differentiation and series expansion
protected:
    ex derivative(const symbol & s) const override { return inherited::derivative(s); }
public:
    ex series(const relational & r, int order, unsigned options = 0) const override { return inherited::series(r, order, options); }
 
    // rational functions
    ex normal(exmap & repl, exmap & rev_lookup, lst & modifier) const override { return inherited::normal(repl, rev_lookup, modifier); }
    ex to_rational(exmap & repl) const override { return inherited::to_rational(repl); }
    ex to_polynomial(exmap & repl) const override { return inherited::to_polynomial(repl); }
 
    // polynomial algorithms
    numeric integer_content() const override { return 1; }
    ex smod(const numeric & xi) const override { return *this; }
    numeric max_coefficient() const override { return 1; }
 
    // indexed objects
    exvector get_free_indices() const override { return exvector(); }
    ex add_indexed(const ex & self, const ex & other) const override { return self + other; }
    ex scalar_mul_indexed(const ex & self, const numeric & other) const override { return self * ex(other); }
    bool contract_with(exvector::iterator self, exvector::iterator other, exvector & v) const override { return false; }
 
    // noncommutativity
    unsigned return_type() const override { return return_types::commutative; }
    return_type_t return_type_tinfo() const override
    {
        return_type_t r;
        r.rl = 0;
        r.tinfo = &typeid(*this);
        return r;
    }
 
protected:
    bool is_equal_same_type(const basic & other) const override
    {
        GINAC_ASSERT(is_a<structure>(other));
        const structure & o = static_cast<const structure &>(other);
 
        return this->struct_is_equal(&obj, &o.obj);
    }
 
    unsigned calchash() const override { return inherited::calchash(); }
 
    // non-virtual functions in this class
public:
    // access to embedded structure
    const T *operator->() const { return &obj; }
    T &get_struct() { return obj; }
    const T &get_struct() const { return obj; }
private:
    T obj;
};
 
 
template <class T, template <class> class CP>
structure<T, CP>::structure() { }
 
template <class T, template <class> class CP>
int structure<T, CP>::compare_same_type(const basic & other) const
{
    GINAC_ASSERT(is_a<structure>(other));
    const structure & o = static_cast<const structure &>(other);
 
    return this->struct_compare(&obj, &o.obj);
}
 
template <class T, template <class> class CP>
registered_class_info structure<T, CP>::reg_info = registered_class_info(registered_class_options(structure::get_class_name(), "basic", typeid(structure<T, CP>)));
 
} // namespace GiNaC
 
#endif // ndef GINAC_STRUCTURE_H