/* -*- C++ -*-

 * Cppcheck - A tool for static C/C++ code analysis

 * Copyright (C) 2007-2024 Cppcheck team.

 *

 * 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 3 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 <http://www.gnu.org/licenses/>.

 */

#ifndef GUARD_PROGRAMMEMORY_H

#define GUARD_PROGRAMMEMORY_H

#include "config.h"

#include "mathlib.h"

#include "vfvalue.h" // needed for alias

#include <cstddef>

#include <functional>

#include <map>

#include <memory>

#include <string>

#include <unordered_map>

#include <utility>

#include <vector>

class Scope;

class Token;

class Settings;

// Class used to handle heterogeneous lookup in unordered_map(since we can't use C++20 yet)

struct ExprIdToken {

    const Token* tok = nullptr;

    nonneg int exprid = 0;

    ExprIdToken() = default;

    // cppcheck-suppress noExplicitConstructor

    // NOLINTNEXTLINE(google-explicit-constructor)

    ExprIdToken(const Token* tok);

    // TODO: Make this constructor only available from ProgramMemory

    // cppcheck-suppress noExplicitConstructor

    // NOLINTNEXTLINE(google-explicit-constructor)

    ExprIdToken(nonneg int exprid) : exprid(exprid) {}

    nonneg int getExpressionId() const;

    bool operator==(const ExprIdToken& rhs) const {

        return getExpressionId() == rhs.getExpressionId();

    }

    bool operator<(const ExprIdToken& rhs) const {

        return getExpressionId() < rhs.getExpressionId();

    }

    template<class T, class U>

    friend bool operator!=(const T& lhs, const U& rhs)

    {

        return !(lhs == rhs);

    }

    template<class T, class U>

    friend bool operator<=(const T& lhs, const U& rhs)

    {

        return !(lhs > rhs);

    }

    template<class T, class U>

    friend bool operator>(const T& lhs, const U& rhs)

    {

        return rhs < lhs;

    }

    template<class T, class U>

    friend bool operator>=(const T& lhs, const U& rhs)

    {

        return !(lhs < rhs);

    }

    const Token& operator*() const NOEXCEPT {

        return *tok;

    }

    const Token* operator->() const NOEXCEPT {

        return tok;

    }

    struct Hash {

        std::size_t operator()(ExprIdToken etok) const;

    };

};

struct CPPCHECKLIB ProgramMemory {

    using Map = std::unordered_map<ExprIdToken, ValueFlow::Value, ExprIdToken::Hash>;

    ProgramMemory() : mValues(new Map()) {}

    explicit ProgramMemory(Map values) : mValues(new Map(std::move(values))) {}

    void setValue(const Token* expr, const ValueFlow::Value& value);

    const ValueFlow::Value* getValue(nonneg int exprid, bool impossible = false) const;

    bool getIntValue(nonneg int exprid, MathLib::bigint& result) const;

    void setIntValue(const Token* expr, MathLib::bigint value, bool impossible = false);

    bool getContainerSizeValue(nonneg int exprid, MathLib::bigint& result) const;

    bool getContainerEmptyValue(nonneg int exprid, MathLib::bigint& result) const;

    void setContainerSizeValue(const Token* expr, MathLib::bigint value, bool isEqual = true);

    void setUnknown(const Token* expr);

    bool getTokValue(nonneg int exprid, const Token*& result) const;

    bool hasValue(nonneg int exprid);

    const ValueFlow::Value& at(nonneg int exprid) const;

    ValueFlow::Value& at(nonneg int exprid);

    void erase_if(const std::function<bool(const ExprIdToken&)>& pred);

    void swap(ProgramMemory &pm) NOEXCEPT;

    void clear();

    bool empty() const;

    void replace(ProgramMemory pm);

    Map::const_iterator begin() const {

        return mValues->cbegin();

    }

    Map::const_iterator end() const {

        return mValues->cend();

    }

    friend bool operator==(const ProgramMemory& x, const ProgramMemory& y) {

        return x.mValues == y.mValues;

    }

    friend bool operator!=(const ProgramMemory& x, const ProgramMemory& y) {

        return x.mValues != y.mValues;

    }

private:

    void copyOnWrite();

    std::shared_ptr<Map> mValues;

};

struct ProgramMemoryState {

    ProgramMemory state;

    std::map<nonneg int, const Token*> origins;

    const Settings& settings;

    explicit ProgramMemoryState(const Settings& s);

    void replace(ProgramMemory pm, const Token* origin = nullptr);

    void addState(const Token* tok, const ProgramMemory::Map& vars);

    void assume(const Token* tok, bool b, bool isEmpty = false);

    void removeModifiedVars(const Token* tok);

    ProgramMemory get(const Token* tok, const Token* ctx, const ProgramMemory::Map& vars) const;

};

std::vector<ValueFlow::Value> execute(const Scope* scope, ProgramMemory& pm, const Settings& settings);

void execute(const Token* expr,

             ProgramMemory& programMemory,

             MathLib::bigint* result,

             bool* error,

             const Settings& settings);

/**

 * Is condition always false when variable has given value?

 * \param condition   top ast token in condition

 * \param pm   program memory

 */

bool conditionIsFalse(const Token* condition, ProgramMemory pm, const Settings& settings);

/**

 * Is condition always true when variable has given value?

 * \param condition   top ast token in condition

 * \param pm   program memory

 */

bool conditionIsTrue(const Token* condition, ProgramMemory pm, const Settings& settings);

/**

 * Get program memory by looking backwards from given token.

 */

ProgramMemory getProgramMemory(const Token* tok, const Token* expr, const ValueFlow::Value& value, const Settings& settings);

ValueFlow::Value evaluateLibraryFunction(const std::unordered_map<nonneg int, ValueFlow::Value>& args,

                                         const std::string& returnValue,

                                         const Settings& settings,

                                         bool cpp);

#endif