Evaluate C define expressions using postfix evaluation, and rename 'asm' to 'parseutil'

parseutil.cpp

@@ -0,0 +1,199 @@
+#include "parseutil.h"
+
+#include <QDebug>
+#include <QRegularExpression>
+#include <QStack>
+
+ParseUtil::ParseUtil()
+{
+}
+
+void ParseUtil::strip_comment(QString *line) {
+    bool in_string = false;
+    for (int i = 0; i < line->length(); i++) {
+        if (line->at(i) == '"') {
+            in_string = !in_string;
+        } else if (line->at(i) == '@') {
+            if (!in_string) {
+                line->truncate(i);
+                break;
+            }
+        }
+    }
+}
+
+QList<QStringList>* ParseUtil::parseAsm(QString text) {
+    QList<QStringList> *parsed = new QList<QStringList>;
+    QStringList lines = text.split('\n');
+    for (QString line : lines) {
+        QString label;
+        //QString macro;
+        //QStringList *params;
+        strip_comment(&line);
+        if (line.trimmed().isEmpty()) {
+        } else if (line.contains(':')) {
+            label = line.left(line.indexOf(':'));
+            QStringList *list = new QStringList;
+            list->append(".label"); // This is not a real keyword. It's used only to make the output more regular.
+            list->append(label);
+            parsed->append(*list);
+            // There should not be anything else on the line.
+            // gas will raise a syntax error if there is.
+        } else {
+            line = line.trimmed();
+            //parsed->append(line.split(QRegExp("\\s*,\\s*")));
+            QString macro;
+            QStringList params;
+            int index = line.indexOf(QRegExp("\\s+"));
+            macro = line.left(index);
+            params = line.right(line.length() - index).trimmed().split(QRegExp("\\s*,\\s*"));
+            params.prepend(macro);
+            parsed->append(params);
+        }
+        //if (macro != NULL) {
+        //    if (macros->contains(macro)) {
+        //        void* function = macros->value(macro);
+        //        if (function != NULL) {
+        //            std::function function(params);
+        //        }
+        //    }
+        //}
+    }
+    return parsed;
+}
+
+int ParseUtil::evaluateDefine(QString define, QMap<QString, int>* knownDefines) {
+    QList<Token> tokens = tokenizeExpression(define, knownDefines);
+    QList<Token> postfixExpression = generatePostfix(tokens);
+    return evaluatePostfix(postfixExpression);
+}
+
+QList<Token> ParseUtil::tokenizeExpression(QString expression, QMap<QString, int>* knownIdentifiers) {
+    QList<Token> tokens;
+
+    QStringList tokenTypes = (QStringList() << "hex" << "decimal" << "identifier" << "operator" << "leftparen" << "rightparen");
+    QRegularExpression re("^(?<hex>0x[0-9a-fA-F]+)|(?<decimal>[0-9]+)|(?<identifier>[a-zA-Z_0-9]+)|(?<operator>[+\\-*\\/<>|^%]+)|(?<leftparen>\\()|(?<rightparen>\\))");
+
+    expression = expression.trimmed();
+    while (!expression.isEmpty()) {
+        QRegularExpressionMatch match = re.match(expression);
+        if (!match.hasMatch()) {
+            qDebug() << "Failed to tokenize expression: " << expression;
+            break;
+        }
+        for (QString tokenType : tokenTypes) {
+            QString token = match.captured(tokenType);
+            if (!token.isEmpty()) {
+                if (tokenType == "identifier") {
+                    if (knownIdentifiers->contains(token)) {
+                        QString actualToken = QString("%1").arg(knownIdentifiers->value(token));
+                        expression = expression.replace(0, token.length(), actualToken);
+                        token = actualToken;
+                        tokenType = "decimal";
+                    } else {
+                        qDebug() << "Unknown identifier found in expression: " << token;
+                    }
+                }
+
+                tokens.append(Token(token, tokenType));
+                expression = expression.remove(0, token.length()).trimmed();
+                break;
+            }
+        }
+    }
+    return tokens;
+}
+
+QMap<QString, int> Token::precedenceMap = QMap<QString, int>(
+{
+    {"*", 3},
+    {"/", 3},
+    {"+", 4},
+    {"-", 4},
+    {"<<", 5},
+    {">>", 5},
+    {"&", 8},
+    {"^", 9},
+    {"|", 10}
+});
+
+// Shunting-yard algorithm for generating postfix notation.
+// https://en.wikipedia.org/wiki/Shunting-yard_algorithm
+QList<Token> ParseUtil::generatePostfix(QList<Token> tokens) {
+    QList<Token> output;
+    QStack<Token> operatorStack;
+    for (Token token : tokens) {
+        if (token.type == TokenType::Number) {
+            output.append(token);
+        } else if (token.value == "(") {
+            operatorStack.push(token);
+        } else if (token.value == ")") {
+            while (!operatorStack.empty() && operatorStack.top().value != "(") {
+                output.append(operatorStack.pop());
+            }
+            if (!operatorStack.empty()) {
+                // pop the left parenthesis token
+                operatorStack.pop();
+            } else {
+                qDebug() << "Mismatched parentheses detected in expression!";
+            }
+        } else {
+            // token is an operator
+            while (!operatorStack.isEmpty()
+                   && operatorStack.top().operatorPrecedence <= token.operatorPrecedence
+                   && operatorStack.top().value != "(") {
+                output.append(operatorStack.pop());
+            }
+            operatorStack.push(token);
+        }
+    }
+
+    while (!operatorStack.isEmpty()) {
+        if (operatorStack.top().value == "(" || operatorStack.top().value == ")") {
+            qDebug() << "Mismatched parentheses detected in expression!";
+        } else {
+            output.append(operatorStack.pop());
+        }
+    }
+
+    return output;
+}
+
+// Evaluate postfix expression.
+// https://en.wikipedia.org/wiki/Reverse_Polish_notation#Postfix_evaluation_algorithm
+int ParseUtil::evaluatePostfix(QList<Token> postfix) {
+    QStack<Token> stack;
+    for (Token token : postfix) {
+        if (token.type == TokenType::Operator) {
+            int op2 = stack.pop().value.toInt(nullptr, 0);
+            int op1 = stack.pop().value.toInt(nullptr, 0);
+            int result = 0;
+            if (token.value == "*") {
+                result = op1 * op2;
+            } else if (token.value == "/") {
+                result = op1 / op2;
+            } else if (token.value == "+") {
+                result = op1 + op2;
+            } else if (token.value == "-") {
+                result = op1 - op2;
+            } else if (token.value == "<<") {
+                result = op1 << op2;
+            } else if (token.value == ">>") {
+                result = op1 >> op2;
+            } else if (token.value == "&") {
+                result = op1 & op2;
+            } else if (token.value == "^") {
+                result = op1 ^ op2;
+            } else if (token.value == "|") {
+                result = op1 | op2;
+            } else {
+                qDebug() << "Unsupported postfix operator: " << token.value;
+            }
+            stack.push(Token(QString("%1").arg(result), "decimal"));
+        } else {
+            stack.push(token);
+        }
+    }
+
+    return stack.pop().value.toInt(nullptr, 0);
+}