mirror of
https://github.com/libretro/dolphin
synced 2024-12-22 13:16:32 +00:00
746 lines
18 KiB
C++
746 lines
18 KiB
C++
// Copyright 2013 Dolphin Emulator Project
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// Licensed under GPLv2+
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// Refer to the license.txt file included.
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#include <cassert>
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#include <cmath>
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#include <iostream>
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#include <memory>
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#include <regex>
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#include <string>
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#include <utility>
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#include <vector>
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#include "Common/Common.h"
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#include "Common/StringUtil.h"
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#include "InputCommon/ControlReference/ExpressionParser.h"
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#include "InputCommon/ControlReference/FunctionExpression.h"
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namespace ciface::ExpressionParser
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{
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using namespace ciface::Core;
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Token::Token(TokenType type_) : type(type_)
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{
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}
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Token::Token(TokenType type_, std::string data_) : type(type_), data(std::move(data_))
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{
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}
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bool Token::IsBinaryOperator() const
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{
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return type >= TOK_BINARY_OPS_BEGIN && type < TOK_BINARY_OPS_END;
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}
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Lexer::Lexer(std::string expr_) : expr(std::move(expr_))
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{
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it = expr.begin();
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}
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std::string Lexer::FetchDelimString(char delim)
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{
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const std::string result = FetchCharsWhile([delim](char c) { return c != delim; });
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if (it != expr.end())
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++it;
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return result;
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}
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std::string Lexer::FetchWordChars()
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{
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// Valid word characters:
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std::regex rx(R"([a-z\d_])", std::regex_constants::icase);
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return FetchCharsWhile([&rx](char c) { return std::regex_match(std::string(1, c), rx); });
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}
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Token Lexer::GetDelimitedLiteral()
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{
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return Token(TOK_LITERAL, FetchDelimString('\''));
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}
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Token Lexer::GetVariable()
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{
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return Token(TOK_VARIABLE, FetchWordChars());
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}
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Token Lexer::GetFullyQualifiedControl()
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{
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return Token(TOK_CONTROL, FetchDelimString('`'));
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}
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Token Lexer::GetBareword(char first_char)
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{
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return Token(TOK_BAREWORD, first_char + FetchWordChars());
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}
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Token Lexer::GetRealLiteral(char first_char)
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{
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std::string value;
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value += first_char;
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value += FetchCharsWhile([](char c) { return isdigit(c, std::locale::classic()) || ('.' == c); });
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if (std::regex_match(value, std::regex(R"(\d+(\.\d+)?)")))
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return Token(TOK_LITERAL, value);
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return Token(TOK_INVALID);
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}
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Token Lexer::PeekToken()
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{
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const auto old_it = it;
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const auto tok = NextToken();
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it = old_it;
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return tok;
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}
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Token Lexer::NextToken()
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{
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if (it == expr.end())
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return Token(TOK_EOF);
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char c = *it++;
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switch (c)
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{
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case ' ':
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case '\t':
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case '\n':
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case '\r':
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return Token(TOK_WHITESPACE);
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case '(':
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return Token(TOK_LPAREN);
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case ')':
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return Token(TOK_RPAREN);
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case '&':
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return Token(TOK_AND);
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case '|':
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return Token(TOK_OR);
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case '!':
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return Token(TOK_NOT);
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case '+':
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return Token(TOK_ADD);
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case '-':
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return Token(TOK_SUB);
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case '*':
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return Token(TOK_MUL);
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case '/':
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return Token(TOK_DIV);
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case '%':
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return Token(TOK_MOD);
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case '=':
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return Token(TOK_ASSIGN);
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case '<':
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return Token(TOK_LTHAN);
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case '>':
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return Token(TOK_GTHAN);
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case ',':
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return Token(TOK_COMMA);
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case '^':
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return Token(TOK_XOR);
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case '\'':
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return GetDelimitedLiteral();
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case '$':
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return GetVariable();
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case '`':
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return GetFullyQualifiedControl();
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default:
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if (isalpha(c, std::locale::classic()))
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return GetBareword(c);
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else if (isdigit(c, std::locale::classic()))
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return GetRealLiteral(c);
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else
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return Token(TOK_INVALID);
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}
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}
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ParseStatus Lexer::Tokenize(std::vector<Token>& tokens)
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{
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while (true)
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{
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const std::size_t string_position = it - expr.begin();
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Token tok = NextToken();
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tok.string_position = string_position;
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tok.string_length = it - expr.begin();
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// Handle /* */ style comments.
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if (tok.type == TOK_DIV && PeekToken().type == TOK_MUL)
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{
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const auto end_of_comment = expr.find("*/", it - expr.begin());
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if (end_of_comment == std::string::npos)
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return ParseStatus::SyntaxError;
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tok.type = TOK_COMMENT;
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tok.string_length = end_of_comment + 4;
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it = expr.begin() + end_of_comment + 2;
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}
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tokens.push_back(tok);
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if (tok.type == TOK_INVALID)
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return ParseStatus::SyntaxError;
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if (tok.type == TOK_EOF)
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break;
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}
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return ParseStatus::Successful;
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}
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class ControlExpression : public Expression
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{
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public:
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// Keep a shared_ptr to the device so the control pointer doesn't become invalid.
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std::shared_ptr<Device> m_device;
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explicit ControlExpression(ControlQualifier qualifier_) : qualifier(qualifier_) {}
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ControlState GetValue() const override
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{
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if (!input)
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return 0.0;
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// Note: Inputs may return negative values in situations where opposing directions are
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// activated. We clamp off the negative values here.
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// FYI: Clamping values greater than 1.0 is purposely not done to support unbounded values in
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// the future. (e.g. raw accelerometer/gyro data)
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return std::max(0.0, input->GetState());
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}
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void SetValue(ControlState value) override
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{
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if (output)
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output->SetState(value);
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}
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int CountNumControls() const override { return (input || output) ? 1 : 0; }
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void UpdateReferences(ControlEnvironment& env) override
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{
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m_device = env.FindDevice(qualifier);
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input = env.FindInput(qualifier);
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output = env.FindOutput(qualifier);
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}
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private:
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ControlQualifier qualifier;
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Device::Input* input = nullptr;
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Device::Output* output = nullptr;
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};
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class BinaryExpression : public Expression
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{
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public:
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TokenType op;
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std::unique_ptr<Expression> lhs;
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std::unique_ptr<Expression> rhs;
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BinaryExpression(TokenType op_, std::unique_ptr<Expression>&& lhs_,
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std::unique_ptr<Expression>&& rhs_)
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: op(op_), lhs(std::move(lhs_)), rhs(std::move(rhs_))
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{
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}
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ControlState GetValue() const override
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{
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switch (op)
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{
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case TOK_AND:
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return std::min(lhs->GetValue(), rhs->GetValue());
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case TOK_OR:
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return std::max(lhs->GetValue(), rhs->GetValue());
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case TOK_ADD:
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return lhs->GetValue() + rhs->GetValue();
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case TOK_SUB:
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return lhs->GetValue() - rhs->GetValue();
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case TOK_MUL:
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return lhs->GetValue() * rhs->GetValue();
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case TOK_DIV:
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{
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const ControlState result = lhs->GetValue() / rhs->GetValue();
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return std::isinf(result) ? 0.0 : result;
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}
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case TOK_MOD:
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{
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const ControlState result = std::fmod(lhs->GetValue(), rhs->GetValue());
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return std::isnan(result) ? 0.0 : result;
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}
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case TOK_ASSIGN:
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{
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lhs->SetValue(rhs->GetValue());
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return lhs->GetValue();
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}
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case TOK_LTHAN:
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return lhs->GetValue() < rhs->GetValue();
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case TOK_GTHAN:
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return lhs->GetValue() > rhs->GetValue();
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case TOK_COMMA:
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{
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// Eval and discard lhs:
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lhs->GetValue();
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return rhs->GetValue();
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}
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case TOK_XOR:
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{
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const auto lval = lhs->GetValue();
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const auto rval = rhs->GetValue();
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return std::max(std::min(1 - lval, rval), std::min(lval, 1 - rval));
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}
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default:
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assert(false);
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return 0;
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}
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}
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void SetValue(ControlState value) override
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{
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// Don't do anything special with the op we have.
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// Treat "A & B" the same as "A | B".
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lhs->SetValue(value);
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rhs->SetValue(value);
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}
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int CountNumControls() const override
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{
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return lhs->CountNumControls() + rhs->CountNumControls();
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}
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void UpdateReferences(ControlEnvironment& env) override
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{
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lhs->UpdateReferences(env);
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rhs->UpdateReferences(env);
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}
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};
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class LiteralExpression : public Expression
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{
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public:
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void SetValue(ControlState) override
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{
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// Do nothing.
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}
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int CountNumControls() const override { return 1; }
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void UpdateReferences(ControlEnvironment&) override
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{
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// Nothing needed.
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}
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protected:
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virtual std::string GetName() const = 0;
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};
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class LiteralReal : public LiteralExpression
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{
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public:
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LiteralReal(ControlState value) : m_value(value) {}
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ControlState GetValue() const override { return m_value; }
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std::string GetName() const override { return ValueToString(m_value); }
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private:
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const ControlState m_value{};
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};
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static ParseResult MakeLiteralExpression(Token token)
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{
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ControlState val{};
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if (TryParse(token.data, &val))
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return ParseResult::MakeSuccessfulResult(std::make_unique<LiteralReal>(val));
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else
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return ParseResult::MakeErrorResult(token, _trans("Invalid literal."));
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}
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class VariableExpression : public Expression
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{
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public:
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VariableExpression(std::string name) : m_name(name) {}
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ControlState GetValue() const override { return *m_value_ptr; }
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void SetValue(ControlState value) override { *m_value_ptr = value; }
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int CountNumControls() const override { return 1; }
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void UpdateReferences(ControlEnvironment& env) override
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{
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m_value_ptr = env.GetVariablePtr(m_name);
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}
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protected:
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const std::string m_name;
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ControlState* m_value_ptr{};
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};
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// This class proxies all methods to its either left-hand child if it has bound controls, or its
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// right-hand child. Its intended use is for supporting old-style barewords expressions.
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class CoalesceExpression : public Expression
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{
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public:
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CoalesceExpression(std::unique_ptr<Expression>&& lhs, std::unique_ptr<Expression>&& rhs)
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: m_lhs(std::move(lhs)), m_rhs(std::move(rhs))
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{
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}
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ControlState GetValue() const override { return GetActiveChild()->GetValue(); }
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void SetValue(ControlState value) override { GetActiveChild()->SetValue(value); }
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int CountNumControls() const override { return GetActiveChild()->CountNumControls(); }
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void UpdateReferences(ControlEnvironment& env) override
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{
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m_lhs->UpdateReferences(env);
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m_rhs->UpdateReferences(env);
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}
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private:
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const std::unique_ptr<Expression>& GetActiveChild() const
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{
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return m_lhs->CountNumControls() > 0 ? m_lhs : m_rhs;
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}
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std::unique_ptr<Expression> m_lhs;
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std::unique_ptr<Expression> m_rhs;
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};
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std::shared_ptr<Device> ControlEnvironment::FindDevice(ControlQualifier qualifier) const
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{
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if (qualifier.has_device)
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return container.FindDevice(qualifier.device_qualifier);
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else
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return container.FindDevice(default_device);
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}
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Device::Input* ControlEnvironment::FindInput(ControlQualifier qualifier) const
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{
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const std::shared_ptr<Device> device = FindDevice(qualifier);
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if (!device)
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return nullptr;
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return device->FindInput(qualifier.control_name);
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}
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Device::Output* ControlEnvironment::FindOutput(ControlQualifier qualifier) const
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{
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const std::shared_ptr<Device> device = FindDevice(qualifier);
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if (!device)
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return nullptr;
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return device->FindOutput(qualifier.control_name);
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}
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ControlState* ControlEnvironment::GetVariablePtr(const std::string& name)
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{
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return &m_variables[name];
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}
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ParseResult ParseResult::MakeEmptyResult()
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{
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ParseResult result;
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result.status = ParseStatus::EmptyExpression;
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return result;
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}
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ParseResult ParseResult::MakeSuccessfulResult(std::unique_ptr<Expression>&& expr)
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{
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ParseResult result;
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result.status = ParseStatus::Successful;
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result.expr = std::move(expr);
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return result;
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}
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ParseResult ParseResult::MakeErrorResult(Token token, std::string description)
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{
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ParseResult result;
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result.status = ParseStatus::SyntaxError;
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result.token = std::move(token);
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result.description = std::move(description);
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return result;
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}
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class Parser
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{
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public:
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explicit Parser(const std::vector<Token>& tokens_) : tokens(tokens_) { m_it = tokens.begin(); }
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ParseResult Parse()
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{
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ParseResult result = ParseToplevel();
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if (ParseStatus::Successful != result.status)
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return result;
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if (Peek().type == TOK_EOF)
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return result;
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return ParseResult::MakeErrorResult(Peek(), _trans("Expected end of expression."));
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}
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private:
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const std::vector<Token>& tokens;
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std::vector<Token>::const_iterator m_it;
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Token Chew()
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{
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const Token tok = Peek();
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if (TOK_EOF != tok.type)
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++m_it;
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return tok;
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}
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Token Peek() { return *m_it; }
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bool Expects(TokenType type)
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{
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Token tok = Chew();
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return tok.type == type;
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}
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ParseResult ParseFunctionArguments(const std::string_view& func_name,
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std::unique_ptr<FunctionExpression>&& func,
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const Token& func_tok)
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{
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std::vector<std::unique_ptr<Expression>> args;
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if (TOK_LPAREN != Peek().type)
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{
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// Single argument with no parens (useful for unary ! function)
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const auto tok = Chew();
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auto arg = ParseAtom(tok);
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if (ParseStatus::Successful != arg.status)
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return arg;
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args.emplace_back(std::move(arg.expr));
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}
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else
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{
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// Chew the L-Paren
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Chew();
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// Check for empty argument list:
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if (TOK_RPAREN == Peek().type)
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{
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Chew();
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}
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else
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{
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while (true)
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{
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// Read one argument.
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// Grab an expression, but stop at comma.
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auto arg = ParseBinary(BinaryOperatorPrecedence(TOK_COMMA));
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if (ParseStatus::Successful != arg.status)
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return arg;
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args.emplace_back(std::move(arg.expr));
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// Right paren is the end of our arguments.
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const Token tok = Chew();
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if (TOK_RPAREN == tok.type)
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break;
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// Comma before the next argument.
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if (TOK_COMMA != tok.type)
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return ParseResult::MakeErrorResult(tok, _trans("Expected comma."));
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};
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}
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}
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const auto argument_validation = func->SetArguments(std::move(args));
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if (std::holds_alternative<FunctionExpression::ExpectedArguments>(argument_validation))
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{
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const auto text = std::string(func_name) + '(' +
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std::get<FunctionExpression::ExpectedArguments>(argument_validation).text +
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')';
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return ParseResult::MakeErrorResult(func_tok, _trans("Expected arguments: " + text));
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}
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return ParseResult::MakeSuccessfulResult(std::move(func));
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}
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ParseResult ParseAtom(const Token& tok)
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{
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switch (tok.type)
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{
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case TOK_BAREWORD:
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{
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auto func = MakeFunctionExpression(tok.data);
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if (!func)
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{
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// Invalid function, interpret this as a bareword control.
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Token control_tok(tok);
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control_tok.type = TOK_CONTROL;
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return ParseAtom(control_tok);
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}
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return ParseFunctionArguments(tok.data, std::move(func), tok);
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}
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case TOK_CONTROL:
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{
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ControlQualifier cq;
|
|
cq.FromString(tok.data);
|
|
return ParseResult::MakeSuccessfulResult(std::make_unique<ControlExpression>(cq));
|
|
}
|
|
case TOK_NOT:
|
|
{
|
|
return ParseFunctionArguments("not", MakeFunctionExpression("not"), tok);
|
|
}
|
|
case TOK_LITERAL:
|
|
{
|
|
return MakeLiteralExpression(tok);
|
|
}
|
|
case TOK_VARIABLE:
|
|
{
|
|
return ParseResult::MakeSuccessfulResult(std::make_unique<VariableExpression>(tok.data));
|
|
}
|
|
case TOK_LPAREN:
|
|
{
|
|
return ParseParens();
|
|
}
|
|
case TOK_SUB:
|
|
{
|
|
// An atom was expected but we got a subtraction symbol.
|
|
// Interpret it as a unary minus function.
|
|
return ParseFunctionArguments("minus", MakeFunctionExpression("minus"), tok);
|
|
}
|
|
default:
|
|
{
|
|
return ParseResult::MakeErrorResult(tok, _trans("Expected start of expression."));
|
|
}
|
|
}
|
|
}
|
|
|
|
static int BinaryOperatorPrecedence(TokenType type)
|
|
{
|
|
switch (type)
|
|
{
|
|
case TOK_MUL:
|
|
case TOK_DIV:
|
|
case TOK_MOD:
|
|
return 1;
|
|
case TOK_ADD:
|
|
case TOK_SUB:
|
|
return 2;
|
|
case TOK_GTHAN:
|
|
case TOK_LTHAN:
|
|
return 3;
|
|
case TOK_AND:
|
|
return 4;
|
|
case TOK_XOR:
|
|
return 5;
|
|
case TOK_OR:
|
|
return 6;
|
|
case TOK_ASSIGN:
|
|
return 7;
|
|
case TOK_COMMA:
|
|
return 8;
|
|
default:
|
|
assert(false);
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
ParseResult ParseBinary(int precedence = 999)
|
|
{
|
|
ParseResult lhs = ParseAtom(Chew());
|
|
|
|
if (lhs.status == ParseStatus::SyntaxError)
|
|
return lhs;
|
|
|
|
std::unique_ptr<Expression> expr = std::move(lhs.expr);
|
|
|
|
// TODO: handle LTR/RTL associativity?
|
|
while (Peek().IsBinaryOperator() && BinaryOperatorPrecedence(Peek().type) < precedence)
|
|
{
|
|
const Token tok = Chew();
|
|
ParseResult rhs = ParseBinary(BinaryOperatorPrecedence(tok.type));
|
|
if (rhs.status == ParseStatus::SyntaxError)
|
|
{
|
|
return rhs;
|
|
}
|
|
|
|
expr = std::make_unique<BinaryExpression>(tok.type, std::move(expr), std::move(rhs.expr));
|
|
}
|
|
|
|
return ParseResult::MakeSuccessfulResult(std::move(expr));
|
|
}
|
|
|
|
ParseResult ParseParens()
|
|
{
|
|
// lparen already chewed
|
|
ParseResult result = ParseToplevel();
|
|
if (result.status != ParseStatus::Successful)
|
|
return result;
|
|
|
|
const auto rparen = Chew();
|
|
if (rparen.type != TOK_RPAREN)
|
|
{
|
|
return ParseResult::MakeErrorResult(rparen, _trans("Expected closing paren."));
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
ParseResult ParseToplevel() { return ParseBinary(); }
|
|
}; // namespace ExpressionParser
|
|
|
|
ParseResult ParseTokens(const std::vector<Token>& tokens)
|
|
{
|
|
return Parser(tokens).Parse();
|
|
}
|
|
|
|
static ParseResult ParseComplexExpression(const std::string& str)
|
|
{
|
|
Lexer l(str);
|
|
std::vector<Token> tokens;
|
|
const ParseStatus tokenize_status = l.Tokenize(tokens);
|
|
if (tokenize_status != ParseStatus::Successful)
|
|
return ParseResult::MakeErrorResult(Token(TOK_INVALID), _trans("Tokenizing failed."));
|
|
|
|
RemoveInertTokens(&tokens);
|
|
return ParseTokens(tokens);
|
|
}
|
|
|
|
void RemoveInertTokens(std::vector<Token>* tokens)
|
|
{
|
|
tokens->erase(std::remove_if(tokens->begin(), tokens->end(),
|
|
[](const Token& tok) {
|
|
return tok.type == TOK_COMMENT || tok.type == TOK_WHITESPACE;
|
|
}),
|
|
tokens->end());
|
|
}
|
|
|
|
static std::unique_ptr<Expression> ParseBarewordExpression(const std::string& str)
|
|
{
|
|
ControlQualifier qualifier;
|
|
qualifier.control_name = str;
|
|
qualifier.has_device = false;
|
|
|
|
return std::make_unique<ControlExpression>(qualifier);
|
|
}
|
|
|
|
ParseResult ParseExpression(const std::string& str)
|
|
{
|
|
if (StripSpaces(str).empty())
|
|
return ParseResult::MakeEmptyResult();
|
|
|
|
auto bareword_expr = ParseBarewordExpression(str);
|
|
ParseResult complex_result = ParseComplexExpression(str);
|
|
|
|
if (complex_result.status != ParseStatus::Successful)
|
|
{
|
|
// This is a bit odd.
|
|
// Return the error status of the complex expression with the fallback barewords expression.
|
|
complex_result.expr = std::move(bareword_expr);
|
|
return complex_result;
|
|
}
|
|
|
|
complex_result.expr = std::make_unique<CoalesceExpression>(std::move(bareword_expr),
|
|
std::move(complex_result.expr));
|
|
return complex_result;
|
|
}
|
|
} // namespace ciface::ExpressionParser
|