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x64dbg/x64_dbg_dbg/expressionparser.cpp

453 lines
13 KiB
C++

#include "expressionparser.h"
#include "value.h"
ExpressionParser::Token::Token(const String & data, const Type type)
{
_data = data;
_type = type;
}
const String & ExpressionParser::Token::data() const
{
return _data;
}
ExpressionParser::Token::Type ExpressionParser::Token::type() const
{
return _type;
}
ExpressionParser::Token::Associativity ExpressionParser::Token::associativity() const
{
switch(_type)
{
case Type::OperatorUnarySub:
case Type::OperatorNot:
return Associativity::RightToLeft;
case Type::OperatorMul:
case Type::OperatorHiMul:
case Type::OperatorDiv:
case Type::OperatorMod:
case Type::OperatorAdd:
case Type::OperatorSub:
case Type::OperatorShl:
case Type::OperatorShr:
case Type::OperatorAnd:
case Type::OperatorXor:
case Type::OperatorOr:
return Associativity::LeftToRight;
default:
return Associativity::Unspecified;
}
}
int ExpressionParser::Token::precedence() const
{
switch(_type)
{
case Type::OperatorUnarySub:
case Type::OperatorNot:
return 7;
case Type::OperatorMul:
case Type::OperatorHiMul:
case Type::OperatorDiv:
case Type::OperatorMod:
return 6;
case Type::OperatorAdd:
case Type::OperatorSub:
return 5;
case Type::OperatorShl:
case Type::OperatorShr:
return 4;
case Type::OperatorAnd:
return 3;
case Type::OperatorXor:
return 2;
case Type::OperatorOr:
return 1;
default:
return 0;
}
}
bool ExpressionParser::Token::isOperator() const
{
return _type != Type::Data && _type != Type::OpenBracket && _type != Type::CloseBracket;
}
ExpressionParser::ExpressionParser(const String & expression)
{
_tokens.clear();
_prefixTokens.clear();
tokenize(fixClosingBrackets(expression));
shuntingYard();
}
String ExpressionParser::fixClosingBrackets(const String & expression)
{
int open = 0;
int close = 0;
size_t len = expression.length();
for(size_t i = 0; i < len; i++)
{
if(expression[i] == '(')
open++;
else if(expression[i] == ')')
close++;
}
String result = expression;
if(close < open)
{
for(int i = 0; i < open - close; i++)
result += ")";
}
return result;
}
void ExpressionParser::tokenize(const String & expression)
{
bool stateMemory = false;
size_t len = expression.length();
for(size_t i = 0; i < len; i++)
{
char ch = expression[i];
switch(ch)
{
case '[':
{
stateMemory = true;
_curToken += ch;
}
break;
case ']':
{
stateMemory = false;
_curToken += ch;
}
break;
default:
{
if(stateMemory)
_curToken += ch;
else
{
switch(ch)
{
case '(':
addOperatorToken(ch, Token::Type::OpenBracket);
break;
case ')':
addOperatorToken(ch, Token::Type::CloseBracket);
break;
case '~':
addOperatorToken(ch, Token::Type::OperatorNot);
break;
case '*':
addOperatorToken(ch, Token::Type::OperatorMul);
break;
case '`':
addOperatorToken(ch, Token::Type::OperatorHiMul);
break;
case '/':
addOperatorToken(ch, Token::Type::OperatorDiv);
break;
case '%':
addOperatorToken(ch, Token::Type::OperatorMod);
break;
case '+':
if(!isUnaryOperator()) //skip all unary add operators
addOperatorToken(ch, Token::Type::OperatorAdd);
break;
case '-':
if(isUnaryOperator())
addOperatorToken(ch, Token::Type::OperatorUnarySub);
else
addOperatorToken(ch, Token::Type::OperatorSub);
break;
case '<':
addOperatorToken(ch, Token::Type::OperatorShl);
break;
case '>':
addOperatorToken(ch, Token::Type::OperatorShr);
break;
case '&':
addOperatorToken(ch, Token::Type::OperatorAnd);
break;
case '^':
addOperatorToken(ch, Token::Type::OperatorXor);
break;
case '|':
addOperatorToken(ch, Token::Type::OperatorOr);
break;
case ' ': //ignore spaces
break;
default:
_curToken += ch;
break;
}
}
}
break;
}
}
if(_curToken.length() != 0) //make sure the last token is added
_tokens.push_back(Token(_curToken, Token::Type::Data));
}
void ExpressionParser::addOperatorToken(const char ch, const Token::Type type)
{
if(_curToken.length()) //add a new data token when there is data in the buffer
{
_tokens.push_back(Token(_curToken, Token::Type::Data));
_curToken.clear();
}
String data;
data += ch;
_tokens.push_back(Token(data, type)); //add the operator token
}
bool ExpressionParser::isUnaryOperator()
{
if(_curToken.length()) //data before the operator means it is no unary operator
return false;
if(!_tokens.size()) //no tokens before the operator means it is an unary operator
return true;
Token lastToken = _tokens[_tokens.size() - 1];
return lastToken.isOperator(); //if the previous operator is a token, the operator is an unary operator
}
void ExpressionParser::shuntingYard()
{
//Implementation of Dijkstra's Shunting-yard algorithm
std::vector<Token> queue;
std::stack<Token> stack;
size_t len = _tokens.size();
//process the tokens
for(size_t i = 0; i < len; i++)
{
Token & token = _tokens[i];
switch(token.type())
{
case Token::Type::Data:
queue.push_back(token);
break;
case Token::Type::OpenBracket:
stack.push(token);
break;
case Token::Type::CloseBracket:
while(true)
{
if(stack.empty()) //empty stack = bracket mismatch
return;
Token curToken = stack.top();
stack.pop();
if(curToken.type() == Token::Type::OpenBracket)
break;
queue.push_back(curToken);
}
break;
default: //operator
Token & o1 = token;
while(!stack.empty())
{
Token o2 = stack.top();
if(o2.isOperator() &&
(o1.associativity() == Token::Associativity::LeftToRight && o1.precedence() <= o2.precedence()) ||
(o1.associativity() == Token::Associativity::RightToLeft && o1.precedence() < o2.precedence()))
{
queue.push_back(o2);
stack.pop();
}
else
break;
}
stack.push(o1);
break;
}
}
//pop the remaining operators
while(!stack.empty())
{
Token curToken = stack.top();
stack.pop();
if(curToken.type() == Token::Type::OpenBracket || curToken.type() == Token::Type::CloseBracket) //brackets on the stack means invalid expression
return;
queue.push_back(curToken);
}
_prefixTokens = queue;
}
#ifdef _WIN64
#include <intrin.h>
static inline unsigned long long umulhi(unsigned long long x, unsigned long long y)
{
unsigned __int64 res;
_umul128(x, y, &res);
return res;
}
static inline long long mulhi(long long x, long long y)
{
__int64 res;
_mul128(x, y, &res);
return res;
}
#else
static inline unsigned int umulhi(unsigned int x, unsigned int y)
{
return (unsigned int)(((unsigned long long)x * y) >> 32);
}
static inline int mulhi(int x, int y)
{
return (int)(((long long)x * y) >> 32);
}
#endif //__MINGW64__
template<typename T>
static bool operation(const ExpressionParser::Token::Type type, const T op1, const T op2, T & result, const bool signedcalc)
{
result = 0;
switch(type)
{
case ExpressionParser::Token::Type::OperatorUnarySub:
result = op1 * ~0;
return true;
case ExpressionParser::Token::Type::OperatorNot:
result = ~op1;
return true;
case ExpressionParser::Token::Type::OperatorMul:
result = op1 * op2;
return true;
case ExpressionParser::Token::Type::OperatorHiMul:
if(signedcalc)
result = mulhi(op1, op2);
else
result = umulhi(op1, op2);
return true;
case ExpressionParser::Token::Type::OperatorDiv:
if(op2 != 0)
{
result = op1 / op2;
return true;
}
return false;
case ExpressionParser::Token::Type::OperatorMod:
if(op2 != 0)
{
result = op1 % op2;
return true;
}
return false;
case ExpressionParser::Token::Type::OperatorAdd:
result = op1 + op2;
return true;
case ExpressionParser::Token::Type::OperatorSub:
result = op1 - op2;
return true;
case ExpressionParser::Token::Type::OperatorShl:
result = op1 << op2;
return true;
case ExpressionParser::Token::Type::OperatorShr:
result = op1 >> op2;
return true;
case ExpressionParser::Token::Type::OperatorAnd:
result = op1 & op2;
return true;
case ExpressionParser::Token::Type::OperatorXor:
result = op1 ^ op2;
return true;
case ExpressionParser::Token::Type::OperatorOr:
result = op1 | op2;
return true;
default:
return false;
}
}
bool ExpressionParser::unsignedoperation(const Token::Type type, const uint op1, const uint op2, uint & result)
{
return operation<uint>(type, op1, op2, result, false);
}
bool ExpressionParser::signedoperation(const Token::Type type, const sint op1, const sint op2, uint & result)
{
sint signedResult;
if(!operation<sint>(type, op1, op2, signedResult, true))
return false;
result = (uint)signedResult;
return true;
}
bool ExpressionParser::calculate(uint & value, bool signedcalc, bool silent, bool baseonly, int* value_size, bool* isvar, bool* hexonly)
{
value = 0;
if(!_prefixTokens.size())
return false;
std::stack<uint> stack;
//calculate the result from the RPN queue
for(const auto & token : _prefixTokens)
{
if(token.isOperator())
{
uint op1 = 0;
uint op2 = 0;
uint result = 0;
switch(token.type())
{
case Token::Type::OperatorUnarySub:
case Token::Type::OperatorNot:
if(stack.size() < 1)
return false;
op1 = stack.top();
stack.pop();
if(signedcalc)
signedoperation(token.type(), op1, op2, result);
else
unsignedoperation(token.type(), op1, op2, result);
stack.push(result);
break;
case Token::Type::OperatorMul:
case Token::Type::OperatorHiMul:
case Token::Type::OperatorDiv:
case Token::Type::OperatorMod:
case Token::Type::OperatorAdd:
case Token::Type::OperatorSub:
case Token::Type::OperatorShl:
case Token::Type::OperatorShr:
case Token::Type::OperatorAnd:
case Token::Type::OperatorXor:
case Token::Type::OperatorOr:
if(stack.size() < 2)
return false;
op2 = stack.top();
stack.pop();
op1 = stack.top();
stack.pop();
if(signedcalc)
signedoperation(token.type(), op1, op2, result);
else
unsignedoperation(token.type(), op1, op2, result);
stack.push(result);
break;
default: //do nothing
break;
}
}
else
{
uint result;
if(!valfromstring_noexpr(token.data().c_str(), &result, silent, baseonly, value_size, isvar, hexonly))
return false;
stack.push(result);
}
}
if(stack.empty()) //empty result stack means error
return false;
value = stack.top();
return true;
}