diff --git a/.rubocop.yml b/.rubocop.yml
index 6a2e616..c507f9d 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -3,6 +3,8 @@ AllCops:
   NewCops: enable
 Naming/MethodName:
   Enabled: false
+Metrics/MethodLength:
+  Enabled: false
 Style/IfUnlessModifier:
   Enabled: false
 Style/StringLiterals:
diff --git a/bin/benchmark b/bin/benchmark
new file mode 100755
index 0000000..a74f234
--- /dev/null
+++ b/bin/benchmark
@@ -0,0 +1,158 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require "bundler/setup"
+require "benchmark"
+
+SIZE = 1_000_000
+COLS = 12
+
+def run_objc_hash
+  dict = ObjRuby::NSMutableDictionary.new
+
+  (0...SIZE).each do |i|
+    if (i % 2).zero?
+      dict.setObject_forKey("foo", i)
+    end
+  end
+
+  raise unless dict.count == SIZE / 2
+
+  (0...SIZE).each do |i|
+    unless dict.objectForKey(i)
+      dict.setObject_forKey("bar", i)
+    end
+  end
+
+  raise unless dict.count == SIZE
+end
+
+def run_ruby_hash
+  hash = {}
+
+  (0...SIZE).each do |i|
+    if (i % 2).zero?
+      hash[i] = "foo"
+    end
+  end
+
+  raise unless hash.size == SIZE / 2
+
+  (0...SIZE).each do |i|
+    unless hash[i]
+      hash[i] = "bar"
+    end
+  end
+
+  raise unless hash.size == SIZE
+end
+
+def run_objc_set
+  set = ObjRuby::NSMutableSet.new
+
+  (0...SIZE).each do |i|
+    if (i % 2).zero?
+      set.addObject(i)
+    end
+  end
+
+  raise unless set.count == SIZE / 2
+
+  (0...SIZE).each do |i|
+    unless set.containsObject(i)
+      set.addObject(i)
+    end
+  end
+
+  raise unless set.count == SIZE
+end
+
+def run_ruby_set
+  set = Set.new
+
+  (0...SIZE).each do |i|
+    if (i % 2).zero?
+      set << i
+    end
+  end
+
+  raise unless set.size == SIZE / 2
+
+  (0...SIZE).each do |i|
+    unless set.include?(i)
+      set << i
+    end
+  end
+
+  raise unless set.size == SIZE
+end
+
+def run_objc_array
+  array = ObjRuby::NSMutableArray.new
+
+  (0...SIZE).each do |i|
+    if (i % 2).zero?
+      array.addObject("foo")
+    end
+  end
+
+  raise unless array.count == SIZE / 2
+
+  (0...SIZE).each do |i|
+    unless (i % 2).zero?
+      array.addObject("bar")
+    end
+  end
+  raise unless array.count == SIZE
+end
+
+def run_ruby_array
+  array = []
+
+  (0...SIZE).each do |i|
+    if (i % 2).zero?
+      array << "foo"
+    end
+  end
+
+  raise unless array.size == SIZE / 2
+
+  (0...SIZE).each do |i|
+    unless (i % 2).zero?
+      array << "bar"
+    end
+  end
+
+  raise unless array.size == SIZE
+end
+
+Benchmark.bm(COLS) do |bm|
+  bm.report("Warmup:") do
+    require "obj_ruby"
+    require "obj_ruby/cocoa"
+  end
+
+  bm.report("NSDictionary:") do
+    run_objc_hash
+  end
+
+  bm.report("Hash:") do
+    run_ruby_hash
+  end
+
+  bm.report("NSSet:") do
+    run_objc_set
+  end
+
+  bm.report("Set:") do
+    run_ruby_set
+  end
+
+  bm.report("NSArray:") do
+    run_objc_array
+  end
+
+  bm.report("Array:") do
+    run_ruby_array
+  end
+end
diff --git a/ext/obj_ext/RIGSBridgeSupportParser.h b/ext/obj_ext/RIGSBridgeSupportParser.h
index 6569708..fe50ac9 100644
--- a/ext/obj_ext/RIGSBridgeSupportParser.h
+++ b/ext/obj_ext/RIGSBridgeSupportParser.h
@@ -25,6 +25,7 @@
 
 @interface RIGSBridgeSupportParser : NSObject<NSXMLParserDelegate>
 {
+  NSString *_className;
   NSString *_methodName;
   NSString *_functionName;
   NSString *_protocolName;
diff --git a/ext/obj_ext/RIGSBridgeSupportParser.m b/ext/obj_ext/RIGSBridgeSupportParser.m
index dc4655f..1ebcf41 100644
--- a/ext/obj_ext/RIGSBridgeSupportParser.m
+++ b/ext/obj_ext/RIGSBridgeSupportParser.m
@@ -54,24 +54,16 @@ - (void)parser:(NSXMLParser *)parser
     [self parseFunctionWithName:[attributeDict objectForKey:@"name"]];
   }
   else if ([elementName isEqualToString:@"retval"]) {
-    [self parseArgWithIndex:-1
-                       type:[attributeDict objectForKey:@"type64"]
-                     printf:nil
-                      block:nil];
+    [self parseArgWithType:[attributeDict objectForKey:@"type64"]
+                     index:@"-1"
+                    printf:nil
+                     block:nil];
   }
   else if ([elementName isEqualToString:@"arg"]) {
-    if (_methodName) {
-      [self parseArgWithIndex:[attributeDict objectForKey:@"index"] ? [[attributeDict objectForKey:@"index"] intValue] : _argIndex++
-                         type:[attributeDict objectForKey:@"type64"]
-                       printf:[attributeDict objectForKey:@"printf_format"]
-                        block:[attributeDict objectForKey:@"function_pointer"]];
-    }
-    else if (_functionName) {
-      [self parseArgWithIndex:_argIndex++
-                         type:[attributeDict objectForKey:@"type64"]
-                       printf:[attributeDict objectForKey:@"printf_format"]
-                        block:nil];
-    }
+    [self parseArgWithType:[attributeDict objectForKey:@"type64"]
+                     index:[attributeDict objectForKey:@"index"]
+                    printf:[attributeDict objectForKey:@"printf_format"]
+                     block:[attributeDict objectForKey:@"function_pointer"]];
   }
 }
 
@@ -79,7 +71,10 @@ - (void)parser:(NSXMLParser *)parser
  didEndElement:(NSString *)elementName 
   namespaceURI:(NSString *)namespaceURI 
  qualifiedName:(NSString *)qName {
-  if ([elementName isEqualToString:@"informal_protocol"]) {
+  if ([elementName isEqualToString:@"class"]) {
+    [self finalizeClass];
+  }
+  else if ([elementName isEqualToString:@"informal_protocol"]) {
     [self finalizeProtocol];
   }
   else if ([elementName isEqualToString:@"method"]) {
@@ -88,7 +83,7 @@ - (void)parser:(NSXMLParser *)parser
   else if ([elementName isEqualToString:@"function"]) {
     [self finalizeFunction];
   }
-  else if ([elementName isEqualToString:@"arg"] || [elementName isEqualToString:@"retval"]) {
+  else if ([elementName isEqualToString:@"retval"] || [elementName isEqualToString:@"arg"]) {
     [self finalizeArg];
   }
 }
@@ -139,36 +134,46 @@ - (void)parseProtocolWithName:(NSString*)name
   _argDepth = 0;
 }
 
-- (void)parseArgWithIndex:(NSInteger)index type:(NSString*)type printf:(NSString*)printf block:(NSString*)block
+- (void)parseArgWithType:(NSString*)type index:(NSString*)index printf:(NSString*)printf block:(NSString*)block
 {
   _argDepth++;
   
   if (_methodName) {
-    if ([printf isEqualToString:@"true"]) {
-      _formatStringIndex = index;
+    if (_argDepth == 1) {
+      if ([printf isEqualToString:@"true"]) {
+        _formatStringIndex = [index integerValue];
+      }
+      if ([block isEqualToString:@"true"] && [type isEqualToString:@"@?"]) {
+        _blockIndex = [index integerValue];
+        _objcTypes = [[type mutableCopy] retain];
+      }
+      if (type) {
+        rb_objc_register_type_arg_from_objc([_methodName UTF8String], [index intValue], [type UTF8String]);
+      }
     }
-    if ([block isEqualToString:@"true"] && [type isEqualToString:@"@?"]) {
-      _blockIndex = index;
-      _objcTypes = [[NSMutableString string] retain];
+    else {
+      if (_objcTypes) {
+        if ([index isEqualToString:@"-1"]) {
+          [_objcTypes insertString:type atIndex:0];
+        }
+        else {
+          [_objcTypes appendString:type];
+        }
+      }
     }
-    if (_objcTypes) {
-      if (index == -1) {
+  }
+  else if (_functionName) {
+    if (_argDepth == 1) {
+      if ([printf isEqualToString:@"true"]) {
+        _formatStringIndex = _argIndex;
+      }
+      if ([index isEqualToString:@"-1"]) {
         [_objcTypes insertString:type atIndex:0];
       }
       else {
         [_objcTypes appendString:type];
       }
-    }
-  }
-  else if (_functionName) {
-    if ([printf isEqualToString:@"true"]) {
-      _formatStringIndex = index;
-    }
-    if (index == -1) {
-      [_objcTypes insertString:type atIndex:0];
-    }
-    else {
-      [_objcTypes appendString:type];
+      _argIndex++;
     }
   }
 }
@@ -252,11 +257,7 @@ - (void)parseEnumWithName:(NSString*)name value:(NSString*)value
 
 - (void)parseClassWithName:(NSString*)name
 {
-  Class objc_class = NSClassFromString(name);
-
-  if (objc_class) {
-    rb_objc_register_class_from_objc(objc_class);
-  }
+  _className = [name retain];
 }
 
 - (NSUInteger)parseStructArgCountWithType:(NSString*)type
@@ -270,6 +271,18 @@ - (NSUInteger)parseStructArgCountWithType:(NSString*)type
   return quoteCount / 2;
 }
 
+- (void)finalizeClass
+{
+  Class objc_class;
+
+  if ((objc_class = NSClassFromString(_className))) {
+    rb_objc_register_class_from_objc(objc_class);
+  }
+  
+  [_className release];
+  _className = nil;
+}
+
 - (void)finalizeProtocol
 {
   [_protocolName release];
@@ -306,7 +319,7 @@ - (void)finalizeArg
   
   if (_blockIndex != -1) {
     if (_methodName) {
-      rb_objc_register_block_from_objc([_methodName UTF8String], _blockIndex, [_objcTypes UTF8String]);
+      rb_objc_register_block_arg_from_objc([_methodName UTF8String], _blockIndex, [_objcTypes UTF8String]);
     }
 
     _blockIndex = -1;
diff --git a/ext/obj_ext/RIGSCore.h b/ext/obj_ext/RIGSCore.h
index 2a7e927..8e91f2c 100644
--- a/ext/obj_ext/RIGSCore.h
+++ b/ext/obj_ext/RIGSCore.h
@@ -40,11 +40,12 @@ VALUE rb_objc_register_instance_method_from_rb(VALUE rb_class, VALUE rb_method);
 void rb_objc_register_float_from_objc(const char *name, double value);
 void rb_objc_register_integer_from_objc(const char *name, long long value);
 void rb_objc_register_struct_from_objc(const char *key, const char *name, const char *args[], size_t argCount);
-void rb_objc_register_format_string_from_objc(const char *selector, size_t index);
-void rb_objc_register_block_from_objc(const char *selector, size_t index, const char *objcTypes);
 void rb_objc_register_constant_from_objc(const char *name, const char *type);
 void rb_objc_register_function_from_objc(const char *name, const char *objcTypes);
 void rb_objc_register_protocol_from_objc(const char *selector, const char *objcTypes);
+void rb_objc_register_format_string_from_objc(const char *selector, size_t index);
+void rb_objc_register_type_arg_from_objc(const char *selector, int index, const char *objcTypes);
+void rb_objc_register_block_arg_from_objc(const char *selector, size_t index, const char *objcTypes);
 
 VALUE rb_objc_import(VALUE rb_self, VALUE rb_name);
 VALUE rb_objc_new(int rigs_argc, VALUE *rigs_argv, VALUE rb_class);
diff --git a/ext/obj_ext/RIGSCore.m b/ext/obj_ext/RIGSCore.m
index 045aab0..033c043 100644
--- a/ext/obj_ext/RIGSCore.m
+++ b/ext/obj_ext/RIGSCore.m
@@ -48,8 +48,20 @@
 // Hash table that maps known ObjC functions to objcTypes encoding
 static NSMapTable *knownFunctions = 0;
 
-// Hash table that maps known ObjC selectors to block objcTypes encoding
-static NSMapTable *knownBlocks = 0;
+// Hash table that maps known ObjC class selectors with class to objcTypes encoding
+static NSMapTable *knownClassMethods = 0;
+
+// Hash table that maps known ObjC instance selectors with class to objcTypes encoding
+static NSMapTable *knownInstanceMethods = 0;
+
+// Hash table that maps known ObjC selectors with arg position to objcTypes encoding
+static NSMapTable *knownTypeArgs = 0;
+
+// Hash table that maps known ObjC selectors with arg position to block objcTypes encoding
+static NSMapTable *knownBlockArgs = 0;
+
+// Hash table that maps known ObjC selectors to printf arg positions (index+1)
+static NSMapTable *knownFormatStrings = 0;
 
 // Hash table that maps known ObjC selectors to objcTypes encoding
 static NSMapTable *knownProtocols = 0;
@@ -57,9 +69,6 @@
 // Hash table that maps known objcTypes encoding to Ruby proxy method implementations
 static NSMapTable *knownImplementations = 0;
 
-// Hash table that maps known ObjC selectors to printf arg positions (index+1)
-static NSMapTable *knownFormatStrings = 0;
-
 // Hash table that contains loaded Framework bundleIdentifiers
 static NSHashTable *knownFrameworks = 0;
 
@@ -154,9 +163,8 @@
 rb_objc_ffi_type_for_type(const char *type)
 {
   ffi_type *inStruct = NULL;
-  unsigned long inStructHash;
   int inStructIndex = 0;
-  long inStructCount = 0;
+  unsigned long inStructCount = 0;
 
   type = rb_objc_skip_type_qualifiers(type);
 
@@ -165,16 +173,15 @@
   }
 
   if (*type == _C_STRUCT_B) {
-    inStructHash = rb_objc_hash_struct(type);
-    type = rb_objc_skip_type_sname(type);
-    inStructCount = rb_array_len(rb_struct_s_members((VALUE)NSMapGet(knownStructs, (void*)inStructHash)));
-                               
+    inStructCount = rb_objc_struct_type_arity(type);
+
     inStruct = (ffi_type *)malloc(sizeof(ffi_type));
     inStruct->size = 0;
     inStruct->alignment = 0;
     inStruct->type = FFI_TYPE_STRUCT;
     inStruct->elements = malloc((inStructCount + 1) * sizeof(ffi_type *));
-    
+
+    type = rb_objc_skip_type_sname(type);
     while (*type != _C_STRUCT_E) {
       inStruct->elements[inStructIndex++] = rb_objc_ffi_type_for_type(type);
       type = rb_objc_skip_typespec(type);
@@ -192,10 +199,10 @@
   case _C_PTR:    
     return &ffi_type_pointer;
   case _C_BOOL:
-  case _C_UCHR:
-    return &ffi_type_uchar;
   case _C_CHR:
     return &ffi_type_schar;
+  case _C_UCHR:
+    return &ffi_type_uchar;
   case _C_SHT:
     return &ffi_type_sshort;
   case _C_USHT:
@@ -285,6 +292,7 @@
 {
   id val;
   Class retClass;
+  Class class;
   VALUE rb_val;
   VALUE rb_class;
   BOOL ret;
@@ -305,10 +313,11 @@ object by calling rb_objc_release() */
     }
 
     retClass = [val classForCoder];
-    if (retClass != [val class] && strncmp(object_getClassName(val), "NSConcrete", 10) == 0) {
+    class = object_getClass(val);
+    if (retClass != class && strncmp(class_getName(class), "NSConcrete", 10) == 0) {
       // [NSAttributedString alloc] returns NSConcreteAttributedString
       // which is where initWithString is defined so we need it defined in Ruby
-      retClass = [val class];
+      retClass = class;
     }
 
     rb_class = (VALUE) NSMapGet(knownClasses, (void *)retClass);
@@ -386,12 +395,12 @@ object by calling rb_objc_release() */
       switch (TYPE(rb_val))
         {
         case T_DATA:
-          if (rb_obj_is_kind_of(rb_val, rb_cTime) == Qtrue) {
-            *(id*)where = rb_objc_date_from_rb(rb_val);
-          }
-          else if (rb_iv_get(CLASS_OF(rb_val), "@objc_class") != Qnil) {
+          if (rb_iv_get(CLASS_OF(rb_val), "@objc_class") != Qnil) {
             Data_Get_Struct(rb_val, void, *(id*)where);
           }
+          else if (rb_obj_is_kind_of(rb_val, rb_cTime) == Qtrue) {
+            *(id*)where = rb_objc_date_from_rb(rb_val);
+          }
           else {
             ret = NO;
           }
@@ -575,12 +584,7 @@ object by calling rb_objc_release() */
       break; 
     }
 
-    if (inStruct) {
-      // skip the component we have just processed
-      type = rb_objc_skip_typespec(type);
-    }
-
-  } while (inStruct && *type != _C_STRUCT_E);
+  } while (inStruct && (type = rb_objc_skip_typespec(type)) && *type != _C_STRUCT_E);
   
   if (ret == NO) {
     /* raise exception - Don't know how to handle this type of argument */
@@ -659,7 +663,6 @@ object by calling rb_objc_release() */
         break;
 
       case _C_CHR:
-        // Assume that if YES or NO then it's a BOOLean
         if (__OBJC_BOOL_IS_BOOL != 1 && *(char *)where == YES) 
           rb_val = Qtrue;
         else if (__OBJC_BOOL_IS_BOOL != 1 && *(char *)where == NO)
@@ -760,15 +763,13 @@ object by calling rb_objc_release() */
         // the end of the running Ruby array
         rb_ary_push(end, rb_val);
       }
-      // skip the type of the component we have just processed
-      type = (char*)rb_objc_skip_typespec(type);
     } else {
       // We are not in a C structure so simply return the
       // Ruby value
       *rb_val_ptr = rb_val;
     }   
 
-  } while (inStruct && *type != _C_STRUCT_E);
+  } while (inStruct && (type = rb_objc_skip_typespec(type)) && *type != _C_STRUCT_E);
 
   if (end != Qnil && NSMapGet(knownStructs, (void*)inStructHash) != NULL) {
     *rb_val_ptr = rb_struct_alloc((VALUE)NSMapGet(knownStructs, (void*)inStructHash), end);
@@ -793,7 +794,7 @@ object by calling rb_objc_release() */
   nbArgs = [signature numberOfArguments];
   objcTypesIndex = 0;
   
-  type = [signature methodReturnType];  
+  type = [signature methodReturnType];
   while (*type) {
     objcTypes[objcTypesIndex++] = *type++;
   }
@@ -961,10 +962,9 @@ object by calling rb_objc_release() */
 }
 
 static VALUE
-rb_objc_dispatch(id rcv, const char *method, NSMethodSignature *signature, int rigs_argc, VALUE *rigs_argv)
+rb_objc_dispatch(id rcv, const char *method, unsigned long hash, const char *types, int rigs_argc, VALUE *rigs_argv)
 {
   void *sym;
-  unsigned long hash;
   int nbArgs;
   int nbArgsExtra;
   int nbArgsAdjust;
@@ -982,9 +982,11 @@ object by calling rb_objc_release() */
   void *closurePtr;
   struct rb_objc_block *block;
   ffi_cif closureCif;
+  NSMethodSignature *signature;
+
+  signature = [NSMethodSignature signatureWithObjCTypes:types];
 
   if (rcv != nil) {
-    // TODO: perhaps check [rcv methodForSelector:sel] for IMP
     nbArgsAdjust = 2;
     switch(*(signature.methodReturnType)) {
 #ifndef __aarch64__
@@ -1006,8 +1008,6 @@ object by calling rb_objc_release() */
     return Qnil;
   }
 
-  hash = rb_objc_hash(method);
-
   nbArgs = (int)[signature numberOfArguments];
   nbArgsExtra = rigs_argc - (nbArgs - nbArgsAdjust);
   
@@ -1058,7 +1058,7 @@ object by calling rb_objc_release() */
   for (i=nbArgsAdjust;i<nbArgs;i++) {
     type = [signature getArgumentTypeAtIndex:i];
     if (strcmp(type, "@?") == 0) {
-      const char* blockObjcTypes = NSMapGet(knownBlocks, (void*)(hash + i - nbArgsAdjust));
+      const char* blockObjcTypes = NSMapGet(knownBlockArgs, (void*)(hash + i - nbArgsAdjust));
       if (blockObjcTypes && rb_objc_build_closure_cif(&closureCif, blockObjcTypes) == FFI_OK) {
         closure = ffi_closure_alloc(sizeof(ffi_closure), &closurePtr);
         if (ffi_prep_closure_loc(closure, &closureCif, rb_objc_block_handler, &rigs_argv[i-nbArgsAdjust], closurePtr) == FFI_OK) {
@@ -1137,17 +1137,21 @@ object by calling rb_objc_release() */
 rb_objc_send(int rigs_argc, VALUE *rigs_argv, VALUE rb_self)
 {
   @autoreleasepool {
-    const char *method;
+    const char *our_method;
     int our_argc;
     VALUE *our_argv;
+    Class class;
     id rcv;
     SEL sel;
-    NSMethodSignature *signature;
+    const char *method;
+    unsigned long hash;
+    NSMapTable *knownMethods;
+    const char *objcTypes;
 
-    method = rb_id2name(rb_frame_this_func());
+    our_method = rb_id2name(rb_frame_this_func());
     our_argc = rigs_argc;
     our_argv = rigs_argv;
-  
+
     if (rb_block_given_p()) {
       our_argc = rigs_argc + 1;
       our_argv = alloca(our_argc * sizeof(VALUE));
@@ -1157,31 +1161,41 @@ object by calling rb_objc_release() */
       our_argv[our_argc-1] = rb_block_proc();
     }
 
+    sel = rb_objc_method_to_sel(our_method, our_argc);
+    if (sel == NULL) {
+      rb_raise(rb_eTypeError, "method %s is not a valid Objective-C selector", our_method);
+    }
+
+    method = sel_getName(sel);
+    hash = rb_objc_hash(method);
+
     /* determine the receiver type - Class or instance ? */
     switch (TYPE(rb_self)) {
     case T_DATA:
       Data_Get_Struct(rb_self, void, rcv);
+      class = object_getClass(rcv);
+      knownMethods = knownInstanceMethods;
       break;
     case T_CLASS:
       rcv = (Class)NUM2LL(rb_iv_get(rb_self, "@objc_class"));
+      class = rcv;
+      knownMethods = knownClassMethods;
       break;
     default:
-      rb_raise(rb_eTypeError, "can't convert %"PRIsVALUE" into compatible objc_msgSend value", rb_self);
+      rb_raise(rb_eTypeError, "can't convert %"PRIsVALUE" into a compatible objc_msgSend value", rb_self);
       break;
     }
 
-    sel = rb_objc_method_to_sel(method, our_argc);
-    if (sel == NULL) {
-      rb_raise(rb_eTypeError, "method %s is not a valid Objective-C selector", method);
-    }
+    do {      
+      objcTypes = NSMapGet(knownMethods, (void*)rb_objc_hash_s(class_getName(class), hash));
+    } while (objcTypes == NULL && (class = class_getSuperclass(class)));
 
-    signature = [rcv methodSignatureForSelector:sel];
-    if (!signature) {
-      rb_raise(rb_eTypeError, "selector %s is missing an Objective-C signature", sel_getName(sel));
+    if (objcTypes == NULL) {
+      rb_raise(rb_eTypeError, "unable to find Objective-C type encodings for method %s", our_method);
     }
 
     @try {
-      return rb_objc_dispatch(rcv, sel_getName(sel), signature, our_argc, our_argv);
+      return rb_objc_dispatch(rcv, method, hash, objcTypes, our_argc, our_argv);
     }
     @catch (NSException *exception) {
       rb_objc_raise_exception(exception);
@@ -1196,24 +1210,17 @@ object by calling rb_objc_release() */
     const char *method;
     unsigned long hash;
     const char *objcTypes;
-    NSMethodSignature *signature;
     
     method = rb_id2name(rb_frame_this_func());
     hash = rb_objc_hash(method);
     objcTypes = NSMapGet(knownFunctions, (void*)hash);
 
-    if (!objcTypes) {
-      return Qnil;
+    if (objcTypes == NULL) {
+      rb_raise(rb_eTypeError, "unable to find Objective-C type encodings for function %s", method);
     }
     
-    signature = [NSMethodSignature signatureWithObjCTypes:objcTypes];
-
-    if (!signature) {
-      return Qnil;
-    }
-
     @try {
-      return rb_objc_dispatch(nil, method, signature, rigs_argc, rigs_argv);
+      return rb_objc_dispatch(nil, method, hash, objcTypes, rigs_argc, rigs_argv);
     }
     @catch (NSException *exception) {
       rb_objc_raise_exception(exception);
@@ -1221,6 +1228,53 @@ object by calling rb_objc_release() */
   }  
 }
 
+static BOOL
+rb_objc_register_method(Class class, Method method)
+{
+  NSMapTable *knownMethods;
+  unsigned long hash;
+  unsigned long chash;
+  void *data;
+  const char *pos;
+  const char *lpos;
+  const char *type;
+  unsigned long typeIndex;
+  char objcTypes[256] = { '\0' };
+
+  pos = method_getTypeEncoding(method);
+  
+  if (strlen(pos) > 255) return NO;
+
+  knownMethods = class_isMetaClass(class) ? knownClassMethods : knownInstanceMethods;
+  hash = rb_objc_hash(sel_getName(method_getName(method)));
+  chash = rb_objc_hash_s(class_getName(class), hash);
+  data = NSMapGet(knownMethods, (void*)chash);
+
+  if (data) return NO;
+
+  pos = rb_objc_skip_type_qualifiers(pos);
+  typeIndex = 0;
+  while((lpos = pos) && (pos = rb_objc_skip_typespec(lpos))) {
+    if (typeIndex != 1 &&
+        typeIndex != 2 &&
+        (type = NSMapGet(knownTypeArgs, (void*)(hash + (typeIndex == 0 ? -1 : typeIndex - 2))))) {
+      strlcat(objcTypes, type, strlen(type) + strlen(objcTypes) + 1);
+    }
+    else {
+      strlcat(objcTypes, lpos, pos - lpos + strlen(objcTypes) + 1);
+    }
+    pos = rb_objc_skip_type_size(pos);
+    pos = rb_objc_skip_type_qualifiers(pos);
+    typeIndex++;
+  }
+
+  data = malloc(sizeof(char) * (strlen(objcTypes) + 1));
+  strcpy(data, objcTypes);
+  NSMapInsertKnownAbsent(knownMethods, (void*)chash, (void*)data);
+
+  return YES;
+}
+
 static unsigned int
 rb_objc_register_instance_methods(Class objc_class, VALUE rb_class)
 {
@@ -1239,6 +1293,7 @@ object by calling rb_objc_release() */
     mthRubyName = rb_objc_sel_to_method(mthSel);
 
     if (mthRubyName == NULL) continue;
+    if (!rb_objc_register_method(objc_class, methods[i])) continue;
 
     rb_define_method(rb_class, mthRubyName, rb_objc_send, -1);
 
@@ -1262,16 +1317,14 @@ object by calling rb_objc_release() */
   SEL mthSel;
   char *mthRubyName;
   char *mthRubyAlias;
-  Class objc_meta_class;
   unsigned int cmth_cnt;
   unsigned int i;
   Method *methods;
   VALUE rb_singleton;
 
-  objc_meta_class = objc_getMetaClass(class_getName(objc_class));
-    
   /* Define all Ruby Class (singleton) methods for this Class */
-  methods = class_copyMethodList(objc_meta_class, &cmth_cnt);
+  objc_class = object_getClass(objc_class);
+  methods = class_copyMethodList(objc_class, &cmth_cnt);
   rb_singleton = rb_singleton_class(rb_class);
 
   for (i=0;i<cmth_cnt;i++) {
@@ -1279,6 +1332,7 @@ object by calling rb_objc_release() */
     mthRubyName = rb_objc_sel_to_method(mthSel);
 
     if (mthRubyName == NULL) continue;
+    if (!rb_objc_register_method(objc_class, methods[i])) continue;
     
     rb_define_method(rb_singleton, mthRubyName, rb_objc_send, -1);
 
@@ -1363,33 +1417,6 @@ object by calling rb_objc_release() */
   rb_define_const(rb_mRigs, name, rb_integer);
 }
 
-void
-rb_objc_register_block_from_objc(const char *selector, size_t index, const char *objcTypes)
-{
-  unsigned long hash;
-  char *data;
-
-  hash = rb_objc_hash(selector) + index;
-
-  if (!NSMapGet(knownBlocks, (void*)hash)) {
-    data = malloc(sizeof(char) * (strlen(objcTypes) + 1));
-    strcpy(data, objcTypes);
-    NSMapInsertKnownAbsent(knownBlocks, (void*)hash, (void*)data);
-  }
-}
-
-void
-rb_objc_register_format_string_from_objc(const char *selector, size_t index)
-{
-  unsigned long hash;
-
-  hash = rb_objc_hash(selector);
-
-  if (!NSMapGet(knownFormatStrings, (void*)hash)) {
-    NSMapInsertKnownAbsent(knownFormatStrings, (void*)hash, (void*)(index + 1));
-  }
-}
-
 void
 rb_objc_register_struct_from_objc(const char *key, const char *name, const char *args[], size_t argCount)
 {
@@ -1427,6 +1454,49 @@ object by calling rb_objc_release() */
   NSMapInsertKnownAbsent(knownStructs, (void*)hash, (void*)rb_struct);
 }
 
+void
+rb_objc_register_type_arg_from_objc(const char *selector, int index, const char *objcTypes)
+{
+  unsigned long hash;
+  char *data;
+
+  hash = rb_objc_hash(selector) + index;
+
+  if (!NSMapGet(knownTypeArgs, (void*)hash)) {
+    data = malloc(sizeof(char) * (strlen(objcTypes) + 1));
+    strcpy(data, objcTypes);
+    NSMapInsertKnownAbsent(knownTypeArgs, (void*)hash, (void*)data);
+  }
+}
+
+
+void
+rb_objc_register_block_arg_from_objc(const char *selector, size_t index, const char *objcTypes)
+{
+  unsigned long hash;
+  char *data;
+
+  hash = rb_objc_hash(selector) + index;
+
+  if (!NSMapGet(knownBlockArgs, (void*)hash)) {
+    data = malloc(sizeof(char) * (strlen(objcTypes) + 1));
+    strcpy(data, objcTypes);
+    NSMapInsertKnownAbsent(knownBlockArgs, (void*)hash, (void*)data);
+  }
+}
+
+void
+rb_objc_register_format_string_from_objc(const char *selector, size_t index)
+{
+  unsigned long hash;
+
+  hash = rb_objc_hash(selector);
+
+  if (!NSMapGet(knownFormatStrings, (void*)hash)) {
+    NSMapInsertKnownAbsent(knownFormatStrings, (void*)hash, (void*)(index + 1));
+  }
+}
+
 VALUE
 rb_objc_register_class_from_objc (Class objc_class)
 {
@@ -1468,7 +1538,7 @@ object by calling rb_objc_release() */
   rb_iv_set(rb_class, "@objc_class", LL2NUM((long long)objc_class));
 
   cmth_cnt = rb_objc_register_class_methods(objc_class, rb_class);
-  imth_cnt = rb_objc_register_instance_methods(objc_class, rb_class);
+  imth_cnt = rb_objc_register_instance_methods(objc_class, rb_class);  
 
   NSDebugLog(@"%d instance and %d class methods defined for class %s", imth_cnt, cmth_cnt, cname);
 
@@ -1767,10 +1837,13 @@ void __attribute__((noreturn))
   knownObjects = NSCreateMapTable(NSNonOwnedPointerMapKeyCallBacks, NSNonOwnedPointerMapValueCallBacks, 0);
   knownStructs = NSCreateMapTable(NSIntegerMapKeyCallBacks, NSNonOwnedPointerMapValueCallBacks, 0);
   knownFunctions = NSCreateMapTable(NSIntegerMapKeyCallBacks, NSNonOwnedPointerMapValueCallBacks, 0);
-  knownBlocks = NSCreateMapTable(NSIntegerMapKeyCallBacks, NSNonOwnedPointerMapValueCallBacks, 0);
+  knownClassMethods = NSCreateMapTable(NSIntegerMapKeyCallBacks, NSNonOwnedPointerMapValueCallBacks, 0);
+  knownInstanceMethods = NSCreateMapTable(NSIntegerMapKeyCallBacks, NSNonOwnedPointerMapValueCallBacks, 0);
+  knownTypeArgs = NSCreateMapTable(NSIntegerMapKeyCallBacks, NSNonOwnedPointerMapValueCallBacks, 0);
+  knownBlockArgs = NSCreateMapTable(NSIntegerMapKeyCallBacks, NSNonOwnedPointerMapValueCallBacks, 0);
+  knownFormatStrings = NSCreateMapTable(NSIntegerMapKeyCallBacks, NSIntegerMapValueCallBacks, 0);
   knownProtocols = NSCreateMapTable(NSIntegerMapKeyCallBacks, NSNonOwnedPointerMapValueCallBacks, 0);
   knownImplementations = NSCreateMapTable(NSIntegerMapKeyCallBacks, NSNonOwnedPointerMapValueCallBacks, 0);
-  knownFormatStrings = NSCreateMapTable(NSIntegerMapKeyCallBacks, NSIntegerMapValueCallBacks, 0);
   knownFrameworks = NSCreateHashTable(NSIntegerHashCallBacks, 0);
 
   // Ruby class methods under the ObjC Ruby module
diff --git a/ext/obj_ext/RIGSUtilities.h b/ext/obj_ext/RIGSUtilities.h
index 6ba6122..5be64fb 100644
--- a/ext/obj_ext/RIGSUtilities.h
+++ b/ext/obj_ext/RIGSUtilities.h
@@ -41,9 +41,13 @@ char *rb_objc_sel_to_method(SEL sel);
 char *rb_objc_sel_to_alias(SEL sel);
 
 unsigned long rb_objc_hash(const char *value);
+unsigned long rb_objc_hash_s(const char *value, unsigned long seed);
 unsigned long rb_objc_hash_struct(const char *value);
+unsigned long rb_objc_struct_type_arity(const char *type);
 const char *rb_objc_skip_type_qualifiers(const char *type);
+const char *rb_objc_skip_type_size(const char *type);
 const char *rb_objc_skip_type_sname(const char *type);
+const char *rb_objc_skip_type_uname(const char *type);
 const char *rb_objc_skip_typespec(const char *type);
 
 #endif /* __RIGSUtilitis_h_GNUSTEP_RUBY_INCLUDE */
diff --git a/ext/obj_ext/RIGSUtilities.m b/ext/obj_ext/RIGSUtilities.m
index 65d8af1..e35f075 100644
--- a/ext/obj_ext/RIGSUtilities.m
+++ b/ext/obj_ext/RIGSUtilities.m
@@ -181,12 +181,17 @@
   return NULL;
 }
 
-
 unsigned long
 rb_objc_hash(const char *value)
+{
+  return rb_objc_hash_s(value, HASH_SEED);
+}
+
+unsigned long
+rb_objc_hash_s(const char *value, unsigned long seed)
 {
   char keyChar;
-  unsigned long hash = HASH_SEED;
+  unsigned long hash = seed;
   
   while ((keyChar = *value++)) {
     hash = ((hash << HASH_BITSHIFT) + hash) + keyChar;
@@ -212,6 +217,14 @@
   return hash;
 }
 
+inline const char *
+rb_objc_skip_type_size(const char *type)
+{
+  while (isdigit(*type)) {
+    ++type;
+  }
+  return type;
+}
 
 inline const char *
 rb_objc_skip_type_qualifiers(const char *type)
@@ -222,10 +235,10 @@
          || *type == _C_OUT
          || *type == _C_BYCOPY
          || *type == _C_BYREF
-         || *type == _C_ONEWAY)
-    {
-      type += 1;
-    }
+         || *type == _C_ONEWAY
+         || *type == _C_ATOMIC) {
+    ++type;
+  }
   return type;
 }
 
@@ -236,36 +249,44 @@
   return type;
 }
 
+inline const char *
+rb_objc_skip_type_uname(const char *type)
+{
+  while (*type != _C_UNION_E && *type++ != '=');
+  return type;
+}
+
+unsigned long
+rb_objc_struct_type_arity(const char *type)
+{
+  unsigned long arity;
+
+  type = rb_objc_skip_type_sname(type);
+  arity = 0;
+
+  while(*type != _C_STRUCT_E) {
+    arity++;
+    type = rb_objc_skip_typespec(type);
+  }
+
+  return arity;
+}
+
 const char *
 rb_objc_skip_typespec(const char *type)
 {
-  /* Skip the variable name if any */
-  if (*type == '"')
-    {
-      for (type++; *type++ != '"';)
-        /* do nothing */;
-    }
-
   type = rb_objc_skip_type_qualifiers(type);
 
   switch (*type) {
 
   case _C_ID:
-    /* An id may be annotated by the actual type if it is known
-       with the @"ClassName" syntax */
-
-    if (*++type != '"')
-      return type;
-    else
-      {
-        while (*++type != '"')
-          /* do nothing */;
-        return type + 1;
-      }
+    /* skip blocks */;
+    while (*++type == _C_UNDEF);
+    return type;
 
-    /* The following are one character type codes */
   case _C_CLASS:
   case _C_SEL:
+  case _C_BOOL:
   case _C_CHR:
   case _C_UCHR:
   case _C_CHARPTR:
@@ -282,58 +303,40 @@
   case _C_DBL:
   case _C_VOID:
   case _C_UNDEF:
-    return ++type;
-    break;
-
-  case _C_ARY_B:
-    /* skip digits, typespec and closing ']' */
-
-    while (isdigit((unsigned char)*++type))
-      /* do nothing */;
-    type = rb_objc_skip_typespec(type);
-    if (*type == _C_ARY_E)
-      return ++type;
-    else
-      {
-        return 0;
-      }
+    /* one character type codes */
+    return type + 1;
 
   case _C_BFLD:
-    /* The new encoding of bitfields is: b 'position' 'type' 'size' */
-    while (isdigit((unsigned char)*++type))
-      /* skip position */;
-    while (isdigit((unsigned char)*++type))
-      /* skip type and size */;
+    /* skip number of bits */
+    while (isdigit((unsigned char)*++type));
     return type;
 
+  case _C_ARY_B:
+    /* skip digits, and elements until closing ']' */
+    while (isdigit((unsigned char)*++type));
+    while (*type != _C_ARY_E)
+      type = rb_objc_skip_typespec(type);
+    return type + 1;
+
   case _C_STRUCT_B:
     /* skip name, and elements until closing '}'  */
     type = rb_objc_skip_type_sname(type);
     while (*type != _C_STRUCT_E)
-      {
-        type = rb_objc_skip_typespec(type);
-      }
-    return ++type;
+      type = rb_objc_skip_typespec(type);
+    return type + 1;
 
   case _C_UNION_B:
     /* skip name, and elements until closing ')'  */
-
-    while (*type != _C_UNION_E && *type++ != '=')
-      /* do nothing */;
+    type = rb_objc_skip_type_uname(type);
     while (*type != _C_UNION_E)
-      {
-        type = rb_objc_skip_typespec(type);
-      }
-    return ++type;
+      type = rb_objc_skip_typespec(type);
+    return type + 1;
 
   case _C_PTR:
-    /* Just skip the following typespec */
-
-    return rb_objc_skip_typespec(++type);
+    /* skip the following typespec */
+    return rb_objc_skip_typespec(type + 1);
 
   default:
-    {
-      return 0;
-    }
+    return 0;
   }
 }
diff --git a/spec/obj_ruby/ns_affine_transform_spec.rb b/spec/obj_ruby/ns_affine_transform_spec.rb
new file mode 100644
index 0000000..8fd99d7
--- /dev/null
+++ b/spec/obj_ruby/ns_affine_transform_spec.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+RSpec.describe ObjRuby::NSAffineTransform do
+  it "can create an instance" do
+    transform = described_class.new
+
+    expect(transform).not_to be_nil
+    expect(transform).to be_a described_class
+  end
+
+  it "can get a struct transform" do
+    transform = described_class.new
+
+    expect(transform.transformStruct).not_to be_nil
+    expect(transform.transformStruct).to be_a ObjRuby::NSAffineTransformStruct
+  end
+
+  it "can set a struct transform" do
+    transform = described_class.new
+    struct = ObjRuby::NSAffineTransformStruct.new(1.0, 1.0, 1.0, 1.0, 1.0, 1.0)
+
+    transform.transformStruct = struct
+
+    expect(transform.transformStruct).not_to be_nil
+    expect(transform.transformStruct).to eq(struct)
+  end
+end
diff --git a/spec/obj_ruby/ns_process_info_spec.rb b/spec/obj_ruby/ns_process_info_spec.rb
new file mode 100644
index 0000000..f4087d2
--- /dev/null
+++ b/spec/obj_ruby/ns_process_info_spec.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+RSpec.describe ObjRuby::NSProcessInfo do
+  it "can create an instance" do
+    info = described_class.new
+
+    expect(info).not_to be_nil
+    expect(info).to be_a described_class
+  end
+
+  it "can retreive operating system versions" do
+    info = described_class.processInfo
+
+    version = info.operatingSystemVersion
+
+    expect(version).not_to be_nil
+    expect(version).to be_a ObjRuby::NSOperatingSystemVersion
+  end
+
+  it "can compare operating system versions" do
+    info = described_class.processInfo
+    version = ObjRuby::NSOperatingSystemVersion.new(10, 0, 0)
+
+    expect(info.isOperatingSystemAtLeastVersion(version)).to be true
+  end
+end