2 files changed, 21 insertions, 8 deletions

diff --git a/src/embind/embind.js b/src/embind/embind.js
index c7848d9c..c164b326 100755
--- a/src/embind/embind.js
+++ b/src/embind/embind.js
@@ -270,17 +270,24 @@ function RegisteredString(stringType, name) {
 }
 
 RegisteredString.prototype.toWireType = function(destructors, value) {
-    var ptr = _malloc(value.length + 1);
-    writeStringToMemory(value, ptr);
+    // assumes 4-byte alignment
+    var length = value.length;
+    var ptr = _malloc(4 + length);
+    HEAP32[ptr >> 2] = length;
+    writeStringToMemory(value, ptr + 4);
     destructors.push(_free);
     destructors.push(ptr);
     return ptr;
 };
 
 RegisteredString.prototype.fromWireType = function(value) {
-    var rv = Pointer_stringify(value);
+    var length = HEAP32[value >> 2];
+    var a = new Array(length);
+    for (var i = 0; i < length; ++i) {
+        a[i] = String.fromCharCode(HEAP8[value + 4 + i]);
+    }
     _free(value);
-    return rv;
+    return a.join('');
 };
 
 function __embind_register_cstring(rawType, name) {
diff --git a/system/include/emscripten/wire.h b/system/include/emscripten/wire.h
index dc612e11..10484a61 100755
--- a/system/include/emscripten/wire.h
+++ b/system/include/emscripten/wire.h
@@ -180,12 +180,18 @@ namespace emscripten {
 
         template<>
         struct BindingType<std::string> {
-            typedef char* WireType;
+            typedef struct {
+                size_t length;
+                char data[1]; // trailing data
+            }* WireType;
             static WireType toWireType(const std::string& v) {
-                return strdup(v.c_str());
+                WireType wt = (WireType)malloc(sizeof(size_t) + v.length());
+                wt->length = v.length();
+                memcpy(wt->data, v.data(), v.length());
+                return wt;
             }
-            static std::string fromWireType(char* v) {
-                return std::string(v);
+            static std::string fromWireType(WireType v) {
+                return std::string(v->data, v->length);
             }
             static void destroy(WireType v) {
                 free(v);