Added FileHeaderUtils

src/main/java/the/bytecode/club/bytecodeviewer/gui/resourcelist/ResourceListPane.java

@@ -37,6 +37,7 @@ import the.bytecode.club.bytecodeviewer.translation.components.TranslatedJCheckB
 import the.bytecode.club.bytecodeviewer.translation.components.TranslatedJTextField;
 import the.bytecode.club.bytecodeviewer.translation.components.TranslatedVisibleComponent;
 import the.bytecode.club.bytecodeviewer.util.FileDrop;
+import the.bytecode.club.bytecodeviewer.util.FileHeaderUtils;
 import the.bytecode.club.bytecodeviewer.util.LazyNameUtil;
 import the.bytecode.club.bytecodeviewer.util.MiscUtils;
 
@@ -346,7 +347,7 @@ public class ResourceListPane extends TranslatedVisibleComponent implements File
         }
         
         //view classes
-        if (content != null && MiscUtils.getFileHeaderMagicNumber(content).equalsIgnoreCase("cafebabe")
+        if (content != null && FileHeaderUtils.doesFileHeaderMatch(content, FileHeaderUtils.JAVA_CLASS_FILE_HEADER)
                 || name.endsWith(".class"))
         {
             try

src/main/java/the/bytecode/club/bytecodeviewer/plugin/strategies/CompiledJavaPluginLaunchStrategy.java

@@ -10,6 +10,7 @@ import org.objectweb.asm.tree.ClassNode;
 import the.bytecode.club.bytecodeviewer.BytecodeViewer;
 import the.bytecode.club.bytecodeviewer.api.Plugin;
 import the.bytecode.club.bytecodeviewer.plugin.PluginLaunchStrategy;
+import the.bytecode.club.bytecodeviewer.util.FileHeaderUtils;
 import the.bytecode.club.bytecodeviewer.util.MiscUtils;
 
 /***************************************************************************
@@ -82,7 +83,7 @@ public class CompiledJavaPluginLaunchStrategy implements PluginLaunchStrategy {
                     String name = entry.getName();
                     if (name.endsWith(".class")) {
                         byte[] bytes = MiscUtils.getBytes(jis);
-                        if (MiscUtils.getFileHeaderMagicNumber(bytes).equalsIgnoreCase("cafebabe")) {
+                        if (FileHeaderUtils.doesFileHeaderMatch(bytes, FileHeaderUtils.JAVA_CLASS_FILE_HEADER)) {
                             try {
                                 ClassReader cr = new ClassReader(bytes);
                                 ClassNode cn = new ClassNode();

src/main/java/the/bytecode/club/bytecodeviewer/resources/ResourceContainerImporter.java

@@ -11,6 +11,7 @@ import org.apache.commons.compress.archivers.zip.ZipFile;
 import org.apache.commons.io.FilenameUtils;
 import org.objectweb.asm.tree.ClassNode;
 import the.bytecode.club.bytecodeviewer.api.ASMUtil;
+import the.bytecode.club.bytecodeviewer.util.FileHeaderUtils;
 import the.bytecode.club.bytecodeviewer.util.MiscUtils;
 
 /***************************************************************************
@@ -109,7 +110,7 @@ public class ResourceContainerImporter
 	public ResourceContainerImporter addClassResource(String name, InputStream stream) throws IOException
 	{
 		byte[] bytes = MiscUtils.getBytes(stream);
-		if (MiscUtils.getFileHeaderMagicNumber(bytes).equalsIgnoreCase("cafebabe"))
+		if (FileHeaderUtils.doesFileHeaderMatch(bytes, FileHeaderUtils.JAVA_CLASS_FILE_HEADER))
 		{
 			try
 			{

src/main/java/the/bytecode/club/bytecodeviewer/resources/importing/impl/ClassResourceImporter.java

@@ -7,6 +7,7 @@ import org.objectweb.asm.tree.ClassNode;
 import the.bytecode.club.bytecodeviewer.BytecodeViewer;
 import the.bytecode.club.bytecodeviewer.resources.ResourceContainer;
 import the.bytecode.club.bytecodeviewer.resources.importing.Importer;
+import the.bytecode.club.bytecodeviewer.util.FileHeaderUtils;
 import the.bytecode.club.bytecodeviewer.util.JarUtils;
 import the.bytecode.club.bytecodeviewer.util.MiscUtils;
 
@@ -42,7 +43,7 @@ public class ClassResourceImporter implements Importer
 			byte[] bytes = MiscUtils.getBytes(fis);
 			ResourceContainer container = new ResourceContainer(file);
 
-			if (MiscUtils.getFileHeaderMagicNumber(bytes).equalsIgnoreCase("cafebabe"))
+			if (FileHeaderUtils.doesFileHeaderMatch(bytes, FileHeaderUtils.JAVA_CLASS_FILE_HEADER))
 			{
 				final ClassNode cn = JarUtils.getNode(bytes);
 

src/main/java/the/bytecode/club/bytecodeviewer/resources/importing/impl/DirectoryResourceImporter.java

@@ -13,6 +13,7 @@ import the.bytecode.club.bytecodeviewer.BytecodeViewer;
 import the.bytecode.club.bytecodeviewer.resources.ResourceContainer;
 import the.bytecode.club.bytecodeviewer.resources.importing.ImportResource;
 import the.bytecode.club.bytecodeviewer.resources.importing.Importer;
+import the.bytecode.club.bytecodeviewer.util.FileHeaderUtils;
 import the.bytecode.club.bytecodeviewer.util.JarUtils;
 import the.bytecode.club.bytecodeviewer.util.MiscUtils;
 
@@ -80,7 +81,7 @@ public class DirectoryResourceImporter implements Importer
 					if (fileName.endsWith(".class"))
 					{
 						byte[] bytes = Files.readAllBytes(Paths.get(child.getAbsolutePath()));
-						if (MiscUtils.getFileHeaderMagicNumber(bytes).equalsIgnoreCase("cafebabe"))
+						if (FileHeaderUtils.doesFileHeaderMatch(bytes, FileHeaderUtils.JAVA_CLASS_FILE_HEADER))
 						{
 							final ClassNode cn = JarUtils.getNode(bytes);
 							allDirectoryClasses.put(FilenameUtils.removeExtension(trimmedPath), cn);

src/main/java/the/bytecode/club/bytecodeviewer/util/FileHeaderUtils.java

@@ -0,0 +1,31 @@
+package the.bytecode.club.bytecodeviewer.util;
+
+import org.apache.commons.lang3.StringUtils;
+
+/**
+ * @author Konloch
+ * @since 8/21/2024
+ */
+public class FileHeaderUtils
+{
+	public static final int JAVA_CLASS_FILE_HEADER = 0xCAFEBABE;
+	
+	public static boolean doesFileHeaderMatch(byte[] bytes, int fileHeader)
+	{
+		int bytesHeader = ((bytes[0] & 0xFF) << 24) |
+				((bytes[1] & 0xFF) << 16) |
+				((bytes[2] & 0xFF) << 8)  |
+				((bytes[3] & 0xFF));
+		
+		return bytesHeader == fileHeader;
+	}
+	
+	public static String getFileHeaderAsString(byte[] bytes)
+	{
+		if(bytes == null || bytes.length < 4)
+			return StringUtils.EMPTY;
+		
+		return String.format("%02X%02X%02X%02X",
+				bytes[0], bytes[1], bytes[2],bytes[3]);
+	}
+}

src/main/java/the/bytecode/club/bytecodeviewer/util/JarUtils.java

@@ -83,7 +83,7 @@ public class JarUtils
                         if (!entry.isDirectory())
                             files.put(name, bytes);
                     } else {
-                        if (MiscUtils.getFileHeaderMagicNumber(bytes).equalsIgnoreCase("cafebabe")) {
+                        if (FileHeaderUtils.doesFileHeaderMatch(bytes, FileHeaderUtils.JAVA_CLASS_FILE_HEADER)) {
                             try {
                                 final ClassNode cn = getNode(bytes);
                                 container.resourceClasses.put(FilenameUtils.removeExtension(name), cn);
@@ -138,7 +138,7 @@ public class JarUtils
                         if (!name.endsWith(".class")) {
                             files.put(name, bytes);
                         } else {
-                            if (MiscUtils.getFileHeaderMagicNumber(bytes).equalsIgnoreCase("cafebabe"))
+                            if (FileHeaderUtils.doesFileHeaderMatch(bytes, FileHeaderUtils.JAVA_CLASS_FILE_HEADER))
                             {
                                 try {
                                     final ClassNode cn = getNode(bytes);
@@ -171,7 +171,7 @@ public class JarUtils
                     final String name = entry.getName();
                     if (name.endsWith(".class")) {
                         byte[] bytes = MiscUtils.getBytes(jis);
-                        if (MiscUtils.getFileHeaderMagicNumber(bytes).equalsIgnoreCase("cafebabe")) {
+                        if (FileHeaderUtils.doesFileHeaderMatch(bytes, FileHeaderUtils.JAVA_CLASS_FILE_HEADER)) {
                             try {
                                 final ClassNode cn = getNode(bytes);
                                 classes.add(cn);

src/main/java/the/bytecode/club/bytecodeviewer/util/MiscUtils.java

@@ -166,15 +166,6 @@ public class MiscUtils
         }
         return i;
     }
-
-    public static String getFileHeaderMagicNumber(byte[] fileContents)
-    {
-        if(fileContents == null || fileContents.length < 4)
-            return StringUtils.EMPTY;
-        
-        return String.format("%02X%02X%02X%02X", fileContents[0],
-                fileContents[1], fileContents[2],fileContents[3]);
-    }
     
     public static File autoAppendFileExtension(String extension, File file)
     {