1 files changed, 9 insertions, 2 deletions
diff --git a/src/preamble.js b/src/preamble.js
index 14bf4d36..9342bf2b 100644
--- a/src/preamble.js
+++ b/src/preamble.js
@@ -472,9 +472,11 @@ Module['getValue'] = getValue;
 var ALLOC_NORMAL = 0; // Tries to use _malloc()
 var ALLOC_STACK = 1; // Lives for the duration of the current function call
 var ALLOC_STATIC = 2; // Cannot be freed
+var ALLOC_NONE = 3; // Do not allocate
 Module['ALLOC_NORMAL'] = ALLOC_NORMAL;
 Module['ALLOC_STACK'] = ALLOC_STACK;
 Module['ALLOC_STATIC'] = ALLOC_STATIC;
+Module['ALLOC_NONE'] = ALLOC_NONE;
 
 // allocate(): This is for internal use. You can use it yourself as well, but the interface
 //             is a little tricky (see docs right below). The reason is that it is optimized
@@ -489,7 +491,7 @@ Module['ALLOC_STATIC'] = ALLOC_STATIC;
 //         is initial data - if @slab is a number, then this does not matter at all and is
 //         ignored.
 // @allocator: How to allocate memory, see ALLOC_*
-function allocate(slab, types, allocator) {
+function allocate(slab, types, allocator, ptr) {
   var zeroinit, size;
   if (typeof slab === 'number') {
     zeroinit = true;
@@ -501,7 +503,12 @@ function allocate(slab, types, allocator) {
 
   var singleType = typeof types === 'string' ? types : null;
 
-  var ret = [_malloc, Runtime.stackAlloc, Runtime.staticAlloc][allocator === undefined ? ALLOC_STATIC : allocator](Math.max(size, singleType ? 1 : types.length));
+  var ret;
+  if (allocator == ALLOC_NONE) {
+    ret = ptr;
+  } else {
+    ret = [_malloc, Runtime.stackAlloc, Runtime.staticAlloc][allocator === undefined ? ALLOC_STATIC : allocator](Math.max(size, singleType ? 1 : types.length));
+  }
 
   if (zeroinit) {
       _memset(ret, 0, size);