assert if, when trying to convert JS string to std::string, the JS string has code units that do not fit in 8 bits

2 files changed, 12 insertions, 1 deletions

diff --git a/src/embind/embind.js b/src/embind/embind.js
index f66b0495..f9b15fa3 100755
--- a/src/embind/embind.js
+++ b/src/embind/embind.js
@@ -336,7 +336,12 @@ function __embind_register_std_string(rawType, name) {
             var ptr = _malloc(4 + length);
             HEAPU32[ptr >> 2] = length;
             for (var i = 0; i < length; ++i) {
-                HEAPU8[ptr + 4 + i] = value.charCodeAt(i);
+                var charCode = value.charCodeAt(i);
+                if (charCode > 255) {
+                    _free(ptr);
+                    throwBindingError('String has UTF-16 code units that do not fit in 8 bits');
+                }
+                HEAPU8[ptr + 4 + i] = charCode;
             }
             destructors.push(_free, ptr);
             return ptr;
diff --git a/tests/embind/embind.test.js b/tests/embind/embind.test.js
index 6f63d543..fec7145a 100755
--- a/tests/embind/embind.test.js
+++ b/tests/embind/embind.test.js
@@ -397,6 +397,12 @@ module({
             assert.equal(expected, cm.get_non_ascii_string());
         });
 
+        test("passing non-8-bit strings from JS to std::string throws", function() {
+            assert.throws(cm.BindingError, function() {
+                cm.emval_test_take_and_return_std_string("\u1234");
+            });
+        });
+
         test("non-ascii wstrings", function() {
             var expected = String.fromCharCode(10) +
                 String.fromCharCode(1234) +