llvmir some opt

frontend/lexer/TokenStream.java

@@ -0,0 +1,42 @@
+package frontend.lexer;
+
+import java.util.ArrayList;
+
+public class TokenStream {
+    private ArrayList<Token> tokens;
+    private int currentIndex;
+
+    public TokenStream(ArrayList<Token> tokens) {
+        this.tokens = tokens;
+    }
+
+    public Token read() {
+        if (currentIndex < tokens.size()) {
+            return tokens.get(currentIndex++);
+        } else {
+            return null;
+        }
+    }
+
+    public void recall() {
+        if (currentIndex > 0) {
+            currentIndex--;
+        }
+    }
+
+    public int getCurrentIndex() {
+        return currentIndex;
+    }
+
+    public void resetIndex(int index) {
+        currentIndex = index;
+    }
+
+    public Token peek(int step) {
+        if (currentIndex + step < tokens.size()) {
+            return tokens.get(currentIndex + step);
+        } else {
+            return null;
+        }
+    }
+}