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ImHex/plugins/builtin/include/content/helpers/math_evaluator.hpp
2022-10-02 14:18:56 +02:00

123 lines
3.5 KiB
C++

#pragma once
#include <hex.hpp>
#include <string>
#include <vector>
#include <queue>
#include <unordered_map>
#include <functional>
#include <optional>
namespace hex {
template<typename T>
class MathEvaluator {
public:
MathEvaluator() = default;
struct Variable {
T value;
bool constant;
};
std::optional<T> evaluate(const std::string &input);
void registerStandardVariables();
void registerStandardFunctions();
void setVariable(const std::string &name, T value, bool constant = false);
void setFunction(const std::string &name, const std::function<std::optional<T>(std::vector<T>)> &function, size_t minNumArgs, size_t maxNumArgs);
std::unordered_map<std::string, Variable> &getVariables() { return this->m_variables; }
[[nodiscard]] bool hasError() const {
return this->m_lastError.has_value();
}
[[nodiscard]] std::optional<std::string> getLastError() const {
return this->m_lastError;
}
private:
void setError(const std::string &error) {
this->m_lastError = error;
}
private:
enum class TokenType
{
Number,
Variable,
Function,
Operator,
Bracket
};
enum class Operator : u16
{
Invalid = 0x000,
Assign = 0x010,
Or = 0x020,
Xor = 0x030,
And = 0x040,
BitwiseOr = 0x050,
BitwiseXor = 0x060,
BitwiseAnd = 0x070,
Equals = 0x080,
NotEquals = 0x081,
GreaterThan = 0x090,
LessThan = 0x091,
GreaterThanOrEquals = 0x092,
LessThanOrEquals = 0x093,
ShiftLeft = 0x0A0,
ShiftRight = 0x0A1,
Addition = 0x0B0,
Subtraction = 0x0B1,
Multiplication = 0x0C0,
Division = 0x0C1,
Modulus = 0x0C2,
Exponentiation = 0x1D0,
Combine = 0x0E0,
BitwiseNot = 0x0F0,
Not = 0x0F1
};
enum class BracketType : std::uint8_t
{
Left,
Right
};
struct Token {
TokenType type;
union {
T number;
Operator op;
BracketType bracketType;
};
std::string name;
std::vector<T> arguments;
};
static i16 comparePrecedence(const Operator &a, const Operator &b);
static bool isLeftAssociative(const Operator &op);
static std::pair<Operator, size_t> toOperator(const std::string &input);
private:
std::optional<std::queue<Token>> parseInput(std::string input);
std::optional<std::queue<Token>> toPostfix(std::queue<Token> inputQueue);
std::optional<T> evaluate(std::queue<Token> postfixTokens);
std::unordered_map<std::string, Variable> m_variables;
std::unordered_map<std::string, std::function<std::optional<T>(std::vector<T>)>> m_functions;
std::optional<std::string> m_lastError;
};
extern template class MathEvaluator<long double>;
extern template class MathEvaluator<i128>;
}