diff --git a/spine-c/include/spine/extension.h b/spine-c/include/spine/extension.h
index ff5e0da6b..e7ec10da6 100644
--- a/spine-c/include/spine/extension.h
+++ b/spine-c/include/spine/extension.h
@@ -54,8 +54,8 @@
 #define SPINE_EXTENSION_H_
 
 /* All allocation uses these. */
-#define MALLOC(TYPE,COUNT) ((TYPE*)malloc(sizeof(TYPE) * COUNT))
-#define CALLOC(TYPE,COUNT) ((TYPE*)calloc(1, sizeof(TYPE) * COUNT))
+#define MALLOC(TYPE,COUNT) ((TYPE*)_malloc(sizeof(TYPE) * COUNT))
+#define CALLOC(TYPE,COUNT) ((TYPE*)_calloc(1, sizeof(TYPE) * COUNT))
 #define NEW(TYPE) CALLOC(TYPE,1)
 
 /* Gets the direct super class. Type safe. */
@@ -74,7 +74,7 @@
 #define VTABLE(TYPE,VALUE) ((_##TYPE##Vtable*)((TYPE*)VALUE)->vtable)
 
 /* Frees memory. Can be used on const. */
-#define FREE(VALUE) free((void*)VALUE)
+#define FREE(VALUE) _free((void*)VALUE)
 
 /* Allocates a new char[], assigns it to TO, and copies FROM to it. Can be used on const. */
 #define MALLOC_STR(TO,FROM) strcpy(CONST_CAST(char*, TO) = (char*)malloc(strlen(FROM) + 1), FROM)
@@ -106,50 +106,59 @@ char* _Util_readFile (const char* path, int* length);
  * Internal API available for extension:
  */
 
+void* _malloc (size_t size);
+void* _calloc (size_t num, size_t size);
+void _free (void* ptr);
+
+void _setMalloc (void* (*_malloc) (size_t size));
+void _setFree (void (*_free) (void* ptr));
+
 char* _readFile (const char* path, int* length);
 
-void _Skeleton_init (Skeleton* self, SkeletonData* data, /**/
+/**/
+
+void _Skeleton_init (Skeleton* self, SkeletonData* data, //
 		void (*dispose) (Skeleton* skeleton));
 void _Skeleton_deinit (Skeleton* self);
 
 /**/
 
-void _Attachment_init (Attachment* self, const char* name, AttachmentType type, /**/
-		void (*dispose) (Attachment* self), /**/
+void _Attachment_init (Attachment* self, const char* name, AttachmentType type, //
+		void (*dispose) (Attachment* self), //
 		void (*draw) (Attachment* self, struct Slot* slot));
 void _Attachment_deinit (Attachment* self);
 
 /**/
 
-void _RegionAttachment_init (RegionAttachment* self, const char* name, /**/
-		void (*dispose) (Attachment* self), /**/
+void _RegionAttachment_init (RegionAttachment* self, const char* name, //
+		void (*dispose) (Attachment* self), //
 		void (*draw) (Attachment* self, struct Slot* slot));
 void _RegionAttachment_deinit (RegionAttachment* self);
 
 /**/
 
-void _Timeline_init (Timeline* self, /**/
-		void (*dispose) (Timeline* self), /**/
+void _Timeline_init (Timeline* self, //
+		void (*dispose) (Timeline* self), //
 		void (*apply) (const Timeline* self, Skeleton* skeleton, float time, float alpha));
 void _Timeline_deinit (Timeline* self);
 
 /**/
 
-void _CurveTimeline_init (CurveTimeline* self, int frameCount, /**/
-		void (*dispose) (Timeline* self), /**/
+void _CurveTimeline_init (CurveTimeline* self, int frameCount, //
+		void (*dispose) (Timeline* self), //
 		void (*apply) (const Timeline* self, Skeleton* skeleton, float time, float alpha));
 void _CurveTimeline_deinit (CurveTimeline* self);
 
 /**/
 
-void _AtlasPage_init (AtlasPage* self, const char* name, /**/
+void _AtlasPage_init (AtlasPage* self, const char* name, //
 		void (*dispose) (AtlasPage* self));
 void _AtlasPage_deinit (AtlasPage* self);
 
 /**/
 
-void _AttachmentLoader_init (AttachmentLoader* self, /**/
-		void (*dispose) (AttachmentLoader* self), /**/
+void _AttachmentLoader_init (AttachmentLoader* self, //
+		void (*dispose) (AttachmentLoader* self), //
 		Attachment* (*newAttachment) (AttachmentLoader* self, Skin* skin, AttachmentType type, const char* name));
 void _AttachmentLoader_deinit (AttachmentLoader* self);
 void _AttachmentLoader_setError (AttachmentLoader* self, const char* error1, const char* error2);
diff --git a/spine-c/src/spine/extension.c b/spine-c/src/spine/extension.c
index fee45b0ac..65fce73df 100644
--- a/spine-c/src/spine/extension.c
+++ b/spine-c/src/spine/extension.c
@@ -30,6 +30,28 @@
 namespace spine {
 #endif
 
+static void* (*mallocFunc) (size_t size) = malloc;
+static void (*freeFunc) (void* ptr) = free;
+
+void* _malloc (size_t size) {
+	return mallocFunc(size);
+}
+void* _calloc (size_t num, size_t size) {
+	void* ptr = mallocFunc(size);
+	if (ptr) memset(ptr, 0, size);
+	return ptr;
+}
+void _free (void* ptr) {
+	freeFunc(ptr);
+}
+
+void _setMalloc (void* (*malloc) (size_t size)) {
+	mallocFunc = malloc;
+}
+void _setFree (void (*free) (void* ptr)) {
+	freeFunc = free;
+}
+
 char* _readFile (const char* path, int* length) {
 	FILE *file = fopen(path, "rb");
 	if (!file) return 0;