Fix hang on UTF-16 LE BOM file

integration_test.py

@@ -502,4 +502,17 @@ def test_define(record_property, tmpdir):  # #589
 
     assert exitcode == 0
     assert stderr == "test.cpp:1: syntax error: failed to expand 'TEST_P', Invalid ## usage when expanding 'TEST_P': Unexpected token ')'\n"
-    assert stdout == '\n'
+    assert stdout == '\n'
+
+def test_utf16_bom(tmpdir):
+    test_file = os.path.join(tmpdir, "test.cpp")
+    with open(test_file, 'wb') as f:
+        f.write(b'\xFF\xFE\x3B\x00')
+
+    args = [test_file]
+
+    exitcode, stdout, stderr = simplecpp(args, cwd=tmpdir)
+
+    assert exitcode == 0
+    assert stderr == ''
+    assert stdout == ';\n'

simplecpp.cpp

@@ -276,7 +276,10 @@ class simplecpp::TokenList::Stream {
     }
 
     unsigned char peekChar() {
-        auto ch = static_cast<unsigned char>(peek());
+        const int pk = peek();
+        auto ch = static_cast<unsigned char>(pk);
+        if (pk == EOF)
+            return ch;
 
         // For UTF-16 encoded files the BOM is 0xfeff/0xfffe. If the
         // character is non-ASCII character then replace it with 0xff