Rewrite regex search so that it pattern checks each instruction without building a string of the whole method first. Regex duration on mobile cpu (i5-7200U) goes down from 2635ms to 430ms for one specific test case.

src/the/bytecode/club/bytecodeviewer/searching/RegexInsnFinder.java

@@ -255,6 +255,43 @@ public class RegexInsnFinder {
                 }
                 offsets[i] = insnString.length();
                 insnString += opcodes[ain.getOpcode()];
+                insnString = getInsString(ain);
+                insnString += " ";
+            }
+        }
+    }
+
+    // Do a pattern check against each instruction directly,
+    // without building a string of the whole method.
+    public static boolean staticScan(ClassNode node, MethodNode mn, Pattern pattern) {
+        final List<AbstractInsnNode> il = new ArrayList<AbstractInsnNode>();
+        for (final AbstractInsnNode ain : mn.instructions.toArray())
+            if (ain.getOpcode() >= 0) {
+                il.add(ain);
+            }
+        return il.stream().anyMatch(ain -> {
+            if (ain.getOpcode() >= 0) {
+                if (ain.getOpcode() >= opcodes.length) {
+                    try {
+                        throw new UnexpectedException(
+                                "Unknown opcode encountered: "
+                                        + ain.getOpcode());
+                    } catch (final UnexpectedException e) {
+                        new the.bytecode.club.bytecodeviewer.api.ExceptionUI(e);
+                    }
+                }
+                String insnString = getInsString(ain);
+                boolean result = pattern.matcher(insnString).find();
+                if(result) {
+                    return true;
+                }
+            }
+            return false;
+        });
+    }
+
+    private static String getInsString(AbstractInsnNode ain) {
+        String insnString = "";
         switch (ain.getType()) {
             case AbstractInsnNode.INT_INSN:
                 final IntInsnNode iin = (IntInsnNode) ain;
@@ -292,9 +329,7 @@ public class RegexInsnFinder {
                 insnString += "{" + manain.dims + "," + manain.desc + "}";
                 break;
         }
-                insnString += " ";
-            }
-        }
+        return insnString;
     }
 
     public void setMethod(final ClassNode ci, final MethodNode mi) {

src/the/bytecode/club/bytecodeviewer/searching/RegexSearch.java

@@ -2,6 +2,7 @@ package the.bytecode.club.bytecodeviewer.searching;
 
 import java.awt.GridLayout;
 import java.util.Iterator;
+import java.util.regex.Pattern;
 
 import javax.swing.JLabel;
 import javax.swing.JPanel;
@@ -12,6 +13,8 @@ import org.objectweb.asm.tree.ClassNode;
 import org.objectweb.asm.tree.MethodNode;
 import the.bytecode.club.bytecodeviewer.util.FileContainer;
 
+import static the.bytecode.club.bytecodeviewer.searching.RegexInsnFinder.processRegex;
+
 /***************************************************************************
  * Bytecode Viewer (BCV) - Java & Android Reverse Engineering Suite        *
  * Copyright (C) 2014 Kalen 'Konloch' Kinloch - http://bytecodeviewer.com  *
@@ -71,21 +74,13 @@ public class RegexSearch implements SearchTypeDetails {
 
         if (srchText.isEmpty())
             return;
-
+        Pattern pattern = Pattern.compile(processRegex(srchText),
+                Pattern.MULTILINE);
         while (methods.hasNext())
         {
             final MethodNode method = methods.next();
 
-            if (regexFinder == null)
-            {
-                regexFinder = new RegexInsnFinder(node, method);
-            }
-            else
-            {
-                regexFinder.setMethod(node, method);
-            }
-
-            if (regexFinder.find(srchText).length > 0)
+            if (RegexInsnFinder.staticScan(node, method, pattern))
             {
                 String desc2 = method.desc;
                 try