1 files changed, 62 insertions, 4 deletions
diff --git a/src/wordEncoder.cpp b/src/wordEncoder.cpp
index 154b4efc..cc8292f8 100644
--- a/src/wordEncoder.cpp
+++ b/src/wordEncoder.cpp
@@ -260,17 +260,75 @@ wordEncoder::Encoding wordEncoder::getEncoding() const
 }
 
 
+// Explicitly force encoding for some charsets
+struct CharsetEncodingEntry
+{
+	CharsetEncodingEntry(const std::string& charset_, const wordEncoder::Encoding encoding_)
+		: charset(charset_), encoding(encoding_)
+	{
+	}
+
+	std::string charset;
+	wordEncoder::Encoding encoding;
+};
+
+CharsetEncodingEntry g_charsetEncodingMap[] =
+{
+	// Use QP encoding for ISO-8859-x charsets
+	CharsetEncodingEntry("iso-8859",     wordEncoder::ENCODING_QP),
+	CharsetEncodingEntry("iso8859",      wordEncoder::ENCODING_QP),
+
+	// RFC-1468 states:
+	//   " ISO-2022-JP may also be used in MIME Part 2 headers.  The "B"
+	//     encoding should be used with ISO-2022-JP text. "
+	// Use Base64 encoding for all ISO-2022 charsets.
+	CharsetEncodingEntry("iso-2022",     wordEncoder::ENCODING_B64),
+	CharsetEncodingEntry("iso2022",      wordEncoder::ENCODING_B64),
+
+	// Last entry is not used
+	CharsetEncodingEntry("", wordEncoder::ENCODING_AUTO)
+};
+
+
+// static
+bool wordEncoder::isEncodingNeeded(const string& buffer, const charset& charset)
+{
+	// Special treatment for some charsets
+	const string cset = utility::stringUtils::toLower(charset.getName());
+
+	for (unsigned int i = 0 ; i < (sizeof(g_charsetEncodingMap) / sizeof(g_charsetEncodingMap[0])) - 1 ; ++i)
+	{
+		if (cset.find(g_charsetEncodingMap[i].charset) != string::npos)
+		{
+			if (g_charsetEncodingMap[i].encoding != wordEncoder::ENCODING_AUTO)
+				return true;
+		}
+	}
+
+	// No encoding is needed if the buffer only contains ASCII chars
+	if (utility::stringUtils::findFirstNonASCIIchar(buffer.begin(), buffer.end()) != string::npos)
+		return true;
+
+	// Force encoding when there are only ASCII chars, but there is
+	// also at least one of '\n' or '\r' (header fields)
+	if (buffer.find_first_of("\n\r") != string::npos)
+		return true;
+
+	return false;
+}
+
+
 // static
 wordEncoder::Encoding wordEncoder::guessBestEncoding
 	(const string& buffer, const charset& charset)
 {
-	// If the charset is ISO-8859-x, set to QP encoding
+	// Special treatment for some charsets
 	const string cset = utility::stringUtils::toLower(charset.getName());
 
-	if (cset.find("iso-8859") != string::npos ||
-	    cset.find("iso8859") != string::npos)
+	for (unsigned int i = 0 ; i < (sizeof(g_charsetEncodingMap) / sizeof(g_charsetEncodingMap[0])) - 1 ; ++i)
 	{
-		return ENCODING_QP;
+		if (cset.find(g_charsetEncodingMap[i].charset) != string::npos)
+			return g_charsetEncodingMap[i].encoding;
 	}
 
 	// Use Base64 if more than 40% non-ASCII, or Quoted-Printable else (default)