Use ASCII-compatible fallback if an encoder has no values defined for code points below U+0020. Bug 399257, r=jshin

intl/uconv/tests/unit/test_bug399257.js

@@ -0,0 +1,53 @@
+// Tests encoding of characters below U+0020
+const Ci = Components.interfaces;
+const Cc = Components.classes;
+const inString = "Hello\u000aWorld";
+const expectedString = "Hello\nWorld";
+
+
+function run_test() {
+    var failures = false;
+    var ccManager = Cc["@mozilla.org/charset-converter-manager;1"]
+        .getService(Ci.nsICharsetConverterManager);
+    var encodingConverter = Cc["@mozilla.org/intl/scriptableunicodeconverter"]
+        .createInstance(Ci.nsIScriptableUnicodeConverter);
+
+    var charsetList = ccManager.getDecoderList();
+    var counter = 0;
+    while (charsetList.hasMore()) {
+	++counter;
+	var charset = charsetList.getNext();
+
+	// exclude known non-ASCII compatible charsets
+	if (charset.substr(0, "UTF-16".length) == "UTF-16" ||
+	    charset.substr(0, "UTF-32".length) == "UTF-32" ||
+	    charset == "x-imap4-modified-utf7") {
+	    dump("skipping " + counter + " " + charset + "\n");
+	    continue;
+	}
+        dump("testing " + counter + " " + charset + "\n");
+
+        try {
+            encodingConverter.charset = charset;
+        } catch(e) {
+            dump("Warning: couldn't set encoder charset to " + charset + "\n");
+            continue;
+        }
+        var codepageString = encodingConverter.ConvertFromUnicode(inString) +
+            encodingConverter.Finish();
+	if (codepageString != expectedString) {
+	    dump(charset + " encoding failed\n");
+	    for (var i = 0; i < expectedString.length; ++i) {
+		if (codepageString.charAt(i) != expectedString.charAt(i)) {
+		    dump(i.toString(16) + ": 0x" +
+			 codepageString.charCodeAt(i).toString(16) + " != " +
+			 expectedString.charCodeAt(i).toString(16) + "\n");
+		}
+	    }
+	    failures = true;
+	}
+    }
+    if (failures) {
+	do_throw("test failed\n");
+    }
+}

intl/uconv/util/nsUnicodeEncodeHelper.cpp

@@ -62,8 +62,13 @@ nsresult nsUnicodeEncodeHelper::ConvertByTable(
 
   while (src < srcEnd) {
     if (!uMapCode((uTable*) aMappingTable, static_cast<PRUnichar>(*(src++)), reinterpret_cast<PRUint16*>(&med))) {
-      res = NS_ERROR_UENC_NOMAPPING;
-      break;
+      if (*(src - 1) < 0x20) {
+        // some tables are missing the 0x00 - 0x20 part
+        med = *(src - 1);
+      } else {
+        res = NS_ERROR_UENC_NOMAPPING;
+        break;
+      }
     }
 
     PRBool charFound;