1 files changed, 88 insertions, 0 deletions
diff --git a/src/util/callback.h b/src/util/callback.h
new file mode 100644
index 0000000..df93b59
--- /dev/null
+++ b/src/util/callback.h
@@ -0,0 +1,88 @@
+#pragma once
+#include "typedef.h"
+
+template <typename T>
+struct FN;
+
+template <typename RET, typename... ARGS>
+struct FN<RET(ARGS...)> {
+  // voodoo
+  template <typename T> struct __strip_ref { using type = T; };
+  template <typename T> struct __strip_ref<T&> { using type = T; };
+  template <typename T> struct __strip_ref<T&&> { using type = T; };
+  template <typename R, typename... A> struct __strip_ref<R(A...)> { using type = R(*)(A...); };
+  template <typename R, typename... A> struct __strip_ref<R(&)(A...)> { using type = R(*)(A...); };
+
+  void* data;
+  U32 size;
+  RET( *invoke )( void*, ARGS... );
+  void( *destroy )( void* );
+  void*( *clone )( void* );
+
+  template <typename F>
+  FN( F&& f ) {
+    using __stripped = typename __strip_ref<F>::type;
+    data = new __stripped( static_cast<F&&>(f) );
+    size = sizeof( __stripped );
+    invoke = pfn( void* d, ARGS... args ) -> RET {
+      return ( *(__stripped*)d )( args... );
+    };
+    destroy = pfn( void* d ) {
+      delete (__stripped*)d;
+    };
+    clone = pfn( void* data ) {
+      return (void*)new __stripped( *(__stripped*)data );
+    };
+  }
+
+  template <>
+  FN( int&& ) : data( 0 ), invoke( 0 ), destroy( 0 ) {}
+  FN() : data( 0 ), invoke( 0 ), destroy( 0 ) {}
+
+  FN( FN&& other ) : data( other.data ), invoke( other.invoke ), destroy( other.destroy ) {
+    other.data = 0;
+    other.invoke = 0;
+    other.destroy = 0;
+  }
+
+  FN& operator=( FN&& other ) {
+    if( this == &other ) return *this;
+    if( destroy ) destroy( data );
+    data = other.data;
+    invoke = other.invoke;
+    destroy = other.destroy;
+    other.data = 0;
+    other.invoke = 0;
+    other.destroy = 0;
+    return *this;
+  }
+
+  FN( const FN& other ) {
+    *this = other;
+  };
+
+  FN& operator=( const FN& other ) {
+    if( !other.data ) {
+      data = 0;
+      invoke = 0;
+      destroy = 0;
+      size = 0;
+      return *this;
+    }
+
+    size = other.size;
+    data = other.clone( other.data );
+    invoke = other.invoke;
+    destroy = other.destroy;
+    clone = other.clone;
+    return *this;
+  }
+
+  ~FN() { if( destroy ) destroy( data ); }
+  operator bool() const { return !!invoke; }
+
+  RET operator()( ARGS... args ) const {
+    return invoke( data, args... );
+  }
+
+};