1 files changed, 153 insertions, 0 deletions
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/PPandMMHelper.java b/src/org/jetbrains/java/decompiler/modules/decompiler/PPandMMHelper.java
new file mode 100644
index 0000000..be90625
--- /dev/null
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/PPandMMHelper.java
@@ -0,0 +1,153 @@
+/*
+ *    Fernflower - The Analytical Java Decompiler
+ *    http://www.reversed-java.com
+ *
+ *    (C) 2008 - 2010, Stiver
+ *
+ *    This software is NEITHER public domain NOR free software 
+ *    as per GNU License. See license.txt for more details.
+ *
+ *    This software is distributed WITHOUT ANY WARRANTY; without 
+ *    even the implied warranty of MERCHANTABILITY or FITNESS FOR 
+ *    A PARTICULAR PURPOSE. 
+ */
+
+package org.jetbrains.java.decompiler.modules.decompiler;
+
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.List;
+
+import org.jetbrains.java.decompiler.modules.decompiler.exps.AssignmentExprent;
+import org.jetbrains.java.decompiler.modules.decompiler.exps.ConstExprent;
+import org.jetbrains.java.decompiler.modules.decompiler.exps.Exprent;
+import org.jetbrains.java.decompiler.modules.decompiler.exps.FunctionExprent;
+import org.jetbrains.java.decompiler.modules.decompiler.sforms.DirectGraph;
+import org.jetbrains.java.decompiler.modules.decompiler.sforms.DirectNode;
+import org.jetbrains.java.decompiler.modules.decompiler.sforms.FlattenStatementsHelper;
+import org.jetbrains.java.decompiler.modules.decompiler.stats.RootStatement;
+import org.jetbrains.java.decompiler.struct.gen.VarType;
+
+public class PPandMMHelper {
+
+	private boolean exprentReplaced;
+	
+	public boolean findPPandMM(RootStatement root) {
+		
+		FlattenStatementsHelper flatthelper = new FlattenStatementsHelper();
+		DirectGraph dgraph = flatthelper.buildDirectGraph(root);
+
+		LinkedList<DirectNode> stack = new LinkedList<DirectNode>();
+		stack.add(dgraph.first);
+		
+		HashSet<DirectNode> setVisited = new HashSet<DirectNode>(); 
+		
+		boolean res = false;
+		
+		while(!stack.isEmpty()) {
+			
+			DirectNode node = stack.removeFirst();
+			
+			if(setVisited.contains(node)) {
+				continue;
+			}
+			setVisited.add(node);
+			
+			res |= processExprentList(node.exprents);
+			
+			stack.addAll(node.succs);
+		}
+		
+		return res;
+	}
+	
+	private boolean processExprentList(List<Exprent> lst) {
+		
+		boolean result = false;
+
+		for(int i=0;i<lst.size();i++) {
+			Exprent exprent = lst.get(i);
+			exprentReplaced = false;
+			
+			Exprent retexpr = processExprentRecursive(exprent);
+			if(retexpr != null) {
+				lst.set(i, retexpr);
+
+				result = true;
+				i--; // process the same exprent again
+			}
+			
+			result |= exprentReplaced;
+		}
+
+		return result;
+	}
+
+	private Exprent processExprentRecursive(Exprent exprent) {
+
+		boolean replaced = true;
+		while(replaced) {
+			replaced = false;
+
+			for(Exprent expr: exprent.getAllExprents()) {
+				Exprent retexpr = processExprentRecursive(expr);
+				if(retexpr != null) {
+					exprent.replaceExprent(expr, retexpr);
+					replaced = true;
+					exprentReplaced = true;
+					break;
+				}
+			}
+		}
+
+		if(exprent.type == Exprent.EXPRENT_ASSIGNMENT) {
+			AssignmentExprent as = (AssignmentExprent)exprent;
+
+			if(as.getRight().type == Exprent.EXPRENT_FUNCTION) {
+				FunctionExprent func = (FunctionExprent)as.getRight();
+
+				VarType midlayer = null;
+				if(func.getFunctype() >= FunctionExprent.FUNCTION_I2L && 
+						func.getFunctype() <= FunctionExprent.FUNCTION_I2S) {
+					midlayer = func.getSimpleCastType();
+					if(func.getLstOperands().get(0).type == Exprent.EXPRENT_FUNCTION) {
+						func = (FunctionExprent)func.getLstOperands().get(0);
+					} else {
+						return null;
+					}
+				}
+
+				if(func.getFunctype() == FunctionExprent.FUNCTION_ADD ||
+						func.getFunctype() == FunctionExprent.FUNCTION_SUB) {
+					Exprent econd = func.getLstOperands().get(0);
+					Exprent econst = func.getLstOperands().get(1);
+
+					if(econst.type != Exprent.EXPRENT_CONST && econd.type == Exprent.EXPRENT_CONST &&
+							func.getFunctype() == FunctionExprent.FUNCTION_ADD) {
+						econd = econst;
+						econst = func.getLstOperands().get(0);
+					}
+
+					if(econst.type == Exprent.EXPRENT_CONST && ((ConstExprent)econst).hasValueOne()) {
+						Exprent left = as.getLeft();
+
+						VarType condtype = econd.getExprType();
+						if(left.equals(econd) && (midlayer == null || midlayer.equals(condtype))) {
+							FunctionExprent ret = new FunctionExprent(
+									func.getFunctype() == FunctionExprent.FUNCTION_ADD?FunctionExprent.FUNCTION_PPI:FunctionExprent.FUNCTION_MMI,
+											Arrays.asList(new Exprent[]{econd}));
+							ret.setImplicitType(condtype);
+
+							exprentReplaced = true;
+							return ret;
+						}
+					}
+				}
+			}
+		}
+
+		return null;
+	}
+	
+}