diff -Naur qt-x11-free-3.3.8b-orig/src/codecs/qbig5codec.cpp qt-x11-free-3.3.8b/src/codecs/qbig5codec.cpp

--- qt-x11-free-3.3.8b-orig/src/codecs/qbig5codec.cpp	2008-01-15 22:09:13.000000000 +0300

+++ qt-x11-free-3.3.8b/src/codecs/qbig5codec.cpp	2008-08-17 09:36:19.000000000 +0400

@@ -556,6 +556,11 @@

     {

 	//qDebug("QBig5Decoder::toUnicode(const char* chars = \"%s\", int len = %d)", chars, len);

 	QString result;

+	if (!chars) return QString::null;

+	if (chars && (chars[0]=='\0' || len==0)) {

+	    result.setLength(0);

+	    return result;

+	}

 	for (int i=0; i<len; i++) {

 	    uchar ch = chars[i];

 	    switch (nbuf) {

@@ -641,6 +646,11 @@

 {

     //qDebug("QBig5Codec::toUnicode(const char* chars \"%s\", int len = %d)", chars, len);

     QString result;

+    if (!chars) return QString::null;

+    if (chars && (chars[0]=='\0' || len==0)) {

+        result.setLength(0);

+	return result;

+    }

     for (int i=0; i<len; i++) {

 	uchar ch = chars[i];

 	if ( IsLatin(ch) ) {

@@ -842,6 +852,11 @@

     {

 	//qDebug("QBig5hkscsDecoder::toUnicode(const char* chars = \"%s\", int len = %d)", chars, len);

 	QString result;

+	if (!chars) return QString::null;

+	if (chars && (chars[0]=='\0' || len==0)) {

+	    result.setLength(0);

+	    return result;

+	}

 	for (int i=0; i<len; i++) {

 	    uchar ch = chars[i];

 	    switch (nbuf) {

@@ -924,6 +939,11 @@

 {

     //qDebug("QBig5hkscsCodec::toUnicode(const char* chars = \"%s\", int len = %d)", chars, len);

     QString result;

+    if (!chars) return QString::null;

+    if (chars && (chars[0]=='\0' || len==0)) {

+        result.setLength(0);

+        return result;

+    }

     for (int i=0; i<len; i++) {

 	uchar ch = chars[i];

 	if ( IsLatin(ch) ) {

diff -Naur qt-x11-free-3.3.8b-orig/src/codecs/qeucjpcodec.cpp qt-x11-free-3.3.8b/src/codecs/qeucjpcodec.cpp

--- qt-x11-free-3.3.8b-orig/src/codecs/qeucjpcodec.cpp	2008-01-15 22:09:13.000000000 +0300

+++ qt-x11-free-3.3.8b/src/codecs/qeucjpcodec.cpp	2008-08-17 09:36:19.000000000 +0400

@@ -216,6 +216,11 @@

 QString QEucJpCodec::toUnicode(const char* chars, int len) const

 {

     QString result;

+    if (!chars) return QString::null;

+    if (chars && (chars[0]=='\0' || len==0)) {

+        result.setLength(0);

+        return result;

+    }

     for (int i=0; i<len; i++) {

 	uchar ch = chars[i];

 	if ( ch < 0x80 ) {

@@ -407,6 +412,11 @@

     QString toUnicode(const char* chars, int len)

     {

 	QString result;

+	if (!chars) return QString::null;

+	if (chars && (chars[0]=='\0' || len==0)) {

+	    result.setLength(0);

+	    return result;

+	}

 	for (int i=0; i<len; i++) {

 	    uchar ch = chars[i];

 	    switch (nbuf) {

diff -Naur qt-x11-free-3.3.8b-orig/src/codecs/qeuckrcodec.cpp qt-x11-free-3.3.8b/src/codecs/qeuckrcodec.cpp

--- qt-x11-free-3.3.8b-orig/src/codecs/qeuckrcodec.cpp	2008-01-15 22:09:13.000000000 +0300

+++ qt-x11-free-3.3.8b/src/codecs/qeuckrcodec.cpp	2008-08-17 09:36:19.000000000 +0400

@@ -158,6 +158,11 @@

 QString QEucKrCodec::toUnicode(const char* chars, int len) const

 {

     QString result;

+    if (!chars) return QString::null;

+    if (chars && (chars[0]=='\0' || len==0)) {

+        result.setLength(0);

+        return result;

+    }

     for (int i=0; i<len; i++) {

 	uchar ch = chars[i];

 	if (ch == 0)

@@ -289,6 +294,11 @@

     QString toUnicode(const char* chars, int len)

     {

 	QString result;

+	if (!chars) return QString::null;

+	if (chars && (chars[0]=='\0' || len==0)) {

+	    result.setLength(0);

+	    return result;

+	}

 	for (int i=0; i<len; i++) {

 	    uchar ch = chars[i];

 	    if (ch == 0)

diff -Naur qt-x11-free-3.3.8b-orig/src/codecs/qgb18030codec.cpp qt-x11-free-3.3.8b/src/codecs/qgb18030codec.cpp

--- qt-x11-free-3.3.8b-orig/src/codecs/qgb18030codec.cpp	2008-01-15 22:09:13.000000000 +0300

+++ qt-x11-free-3.3.8b/src/codecs/qgb18030codec.cpp	2008-08-17 09:36:19.000000000 +0400

@@ -229,6 +229,11 @@

 QString QGb18030Codec::toUnicode(const char* chars, int len) const

 {

     QString result;

+    if (!chars) return QString::null;

+    if (chars && (chars[0]=='\0' || len==0)) {

+        result.setLength(0);

+        return result;

+    }

     int clen;

     //qDebug("QGb18030Codec::toUnicode(const char* chars, int len = %d)", len);

@@ -351,6 +356,11 @@

     QString toUnicode(const char* chars, int len)

     {

 	QString result;

+	if (!chars) return QString::null;

+	if (chars && (chars[0]=='\0' || len==0)) {

+	    result.setLength(0);

+	    return result;

+	}

 	//qDebug("QGb18030Decoder::toUnicode(const char* chars, int len = %d)", len);

 	for (int i=0; i<len; i++) {

 	    uchar ch = chars[i];

@@ -525,6 +535,11 @@

     QString toUnicode(const char* chars, int len)

     {

 	QString result;

+	if (!chars) return QString::null;

+	if (chars && (chars[0]=='\0' || len==0)) {

+	    result.setLength(0);

+	    return result;

+	}

 	//qDebug("QGbkDecoder::toUnicode(const char* chars = \"%s\", int len = %d)", chars, len);

 	for (int i=0; i<len; i++) {

@@ -608,6 +623,11 @@

 QString QGbkCodec::toUnicode(const char* chars, int len) const

 {

     QString result;

+    if (!chars) return QString::null;

+    if (chars && (chars[0]=='\0' || len==0)) {

+        result.setLength(0);

+	return result;

+    }

     int clen;

     //qDebug("QGbkCodec::toUnicode(const char* chars, int len = %d)", len);

@@ -725,6 +745,11 @@

     QString toUnicode(const char* chars, int len)

     {

 	QString result;

+	if (!chars) return QString::null;

+	if (chars && (chars[0]=='\0' || len==0)) {

+	    result.setLength(0);

+	    return result;

+	}

 	//qDebug("QGb2312Decoder::toUnicode(const char* chars, int len = %d)", len);

 	for (int i=0; i<len; i++) {

 	    uchar ch = chars[i];

@@ -808,6 +833,11 @@

 QString QGb2312Codec::toUnicode(const char* chars, int len) const

 {

     QString result;

+    if (!chars) return QString::null;

+    if (chars && (chars[0]=='\0' || len==0)) {

+        result.setLength(0);

+        return result;

+    }

     int clen;

     //qDebug("QGb2312Codec::toUnicode(const char* chars, int len = %d)", len);

diff -Naur qt-x11-free-3.3.8b-orig/src/codecs/qjiscodec.cpp qt-x11-free-3.3.8b/src/codecs/qjiscodec.cpp

--- qt-x11-free-3.3.8b-orig/src/codecs/qjiscodec.cpp	2008-01-15 22:09:13.000000000 +0300

+++ qt-x11-free-3.3.8b/src/codecs/qjiscodec.cpp	2008-08-17 09:36:19.000000000 +0400

@@ -264,6 +264,11 @@

 QString QJisCodec::toUnicode(const char* chars, int len) const

 {

     QString result;

+    if (!chars) return QString::null;

+    if (chars && (chars[0]=='\0' || len==0)) {

+        result.setLength(0);

+	return result;

+    }

     Iso2022State state = Ascii, prev = Ascii;

     for (int i=0; i<len; i++) {

 	uchar ch = chars[i];

@@ -565,6 +570,11 @@

     QString toUnicode(const char* chars, int len)

     {

 	QString result;

+	if (!chars) return QString::null;

+	if (chars && (chars[0]=='\0' || len==0)) {

+	    result.setLength(0);

+	    return result;

+	}

 	for (int i=0; i<len; i++) {

 	    uchar ch = chars[i];

 	    if (esc) {

diff -Naur qt-x11-free-3.3.8b-orig/src/codecs/qrtlcodec.cpp qt-x11-free-3.3.8b/src/codecs/qrtlcodec.cpp

--- qt-x11-free-3.3.8b-orig/src/codecs/qrtlcodec.cpp	2008-01-15 22:09:13.000000000 +0300

+++ qt-x11-free-3.3.8b/src/codecs/qrtlcodec.cpp	2008-08-17 09:36:19.000000000 +0400

@@ -508,6 +508,11 @@

 QString QHebrewCodec::toUnicode(const char* chars, int len ) const

 {

     QString r;

+    if (!chars) return QString::null;

+    if (chars && (chars[0]=='\0' || len==0)) {

+        r.setLength(0);

+	return r;

+    }

     const unsigned char * c = (const unsigned char *)chars;

     QChar::Direction basicDir = QChar::DirON; // neutral, we don't know

diff -Naur qt-x11-free-3.3.8b-orig/src/codecs/qsjiscodec.cpp qt-x11-free-3.3.8b/src/codecs/qsjiscodec.cpp

--- qt-x11-free-3.3.8b-orig/src/codecs/qsjiscodec.cpp	2008-01-15 22:09:13.000000000 +0300

+++ qt-x11-free-3.3.8b/src/codecs/qsjiscodec.cpp	2008-08-17 09:40:45.000000000 +0400

@@ -191,6 +191,11 @@

 {

     uint u;

     QString result;

+    if (!chars) return QString::null;

+    if (chars && (chars[0]=='\0' || len==0)) {

+        result.setLength(0);

+        return result;

+    }

     for (int i=0; i<len; i++) {

 	uchar ch = chars[i];

 	if ( ch < 0x80 || IsKana(ch) ) {

@@ -328,7 +333,12 @@

     QString toUnicode(const char* chars, int len)

     {

 	QString result;

-    uint u= 0;

+	if (!chars) return QString::null;

+	if (chars && (chars[0]=='\0' || len==0)) {

+	    result.setLength(0);

+	    return result;

+	}

+	uint u= 0;

 	for (int i=0; i<len; i++) {

 	    uchar ch = chars[i];

 	    switch (nbuf) {

diff -Naur qt-x11-free-3.3.8b-orig/src/codecs/qtextcodec.cpp qt-x11-free-3.3.8b/src/codecs/qtextcodec.cpp

--- qt-x11-free-3.3.8b-orig/src/codecs/qtextcodec.cpp	2008-01-15 22:09:13.000000000 +0300

+++ qt-x11-free-3.3.8b/src/codecs/qtextcodec.cpp	2008-08-17 09:36:19.000000000 +0400

@@ -469,19 +469,19 @@

 // returns a string containing the letters and numbers from input,

 // with a space separating run of a character class. e.g. "iso8859-1"

 // becomes "iso 8859 1"

-static QString lettersAndNumbers( const char * input )

+static QCString lettersAndNumbers( const char * input )

 {

-    QString result;

+    QCString result;

     QChar c;

     while( input && *input ) {

-	c = *input;

+	c = QChar( *input, 0 );

  	if ( c.isLetter() || c.isNumber() )

- 	    result += c.lower();

+ 	    result += c.lower().cell();

 	if ( input[1] ) {

 	    // add space at character class transition, except

 	    // transition from upper-case to lower-case letter

-	    QChar n( input[1] );

+	    QChar n( input[1], 0 );

 	    if ( c.isLetter() && n.isLetter() ) {

 		if ( c == c.lower() && n == n.upper() )

 		    result += ' ';

@@ -508,8 +508,8 @@

     // if the letters and numbers are the same, we have an "almost"

     // perfect match.

-    QString h( lettersAndNumbers( hint ) );

-    QString n( lettersAndNumbers( name ) );

+    QCString h( lettersAndNumbers( hint ) );

+    QCString n( lettersAndNumbers( name ) );

     if ( h == n )

 	return qstrlen( hint )-1;

@@ -593,6 +593,13 @@

 QString QWindowsLocalCodec::toUnicode(const char* chars, int len) const

 {

+    if ( !chars ) return QString::null;

+    if ( chars && (chars[0]=='\0' || len==0) ) {

+        QString blank;

+        blank.setLength(0);

+        return blank;

+    }

+

     if ( len == 1 && chars ) {          // Optimization; avoids allocation

 	char c[2];

 	c[0] = *chars;

@@ -1000,8 +1007,13 @@

 */

 QString QTextCodec::toUnicode(const char* chars, int len) const

 {

-    if ( chars == 0 )

-	return QString::null;

+    if ( !chars ) return QString::null;

+    if ( chars && (chars[0]=='\0' || len==0) ) {

+        QString blank;

+        blank.setLength(0);

+        return blank;

+    }

+

     QTextDecoder* i = makeDecoder();

     QString result = i->toUnicode(chars,len);

     delete i;

@@ -1477,6 +1489,13 @@

     QString toUnicode(const char* chars, int len) const

     {

+        if ( !chars ) return QString::null;

+        if ( chars && (chars[0]=='\0' || len==0) ) {

+            QString blank;

+            blank.setLength(0);

+            return blank;

+        }

+

 	const uchar* uchars = (const uchar*)chars;

 	QString result;

 	QMultiByteUnicodeTable* multiByte=to_unicode_multiByte;

@@ -1549,6 +1568,13 @@

 QString QTextCodecFromIODDecoder::toUnicode(const char* chars, int len)

 {

+    if ( !chars ) return QString::null;

+    if ( chars && (chars[0]=='\0' || len==0) ) {

+        QString blank;

+        blank.setLength(0);

+        return blank;

+    }

+

     const uchar* uchars = (const uchar*)chars;

     QString result;

     while (len--) {

@@ -2319,13 +2345,17 @@

 QString QSimpleTextCodec::toUnicode(const char* chars, int len) const

 {

-    if ( len <= 0 || chars == 0 )

-	return QString::null;

+    if ( !chars ) return QString::null;

+    if ( chars && (chars[0]=='\0' || len==0) ) {

+        QString blank;

+        blank.setLength(0);

+        return blank;

+    }

     const unsigned char * c = (const unsigned char *)chars;

     int i;

-    for ( i = 0; i < len; i++ )

+    for ( i = 0; i < len || len < 0; i++ )

 	if ( c[i] == '\0' ) {

 	    len = i;

 	    break;

@@ -2515,10 +2545,29 @@

 QString QLatin1Codec::toUnicode(const char* chars, int len) const

 {

-    if ( chars == 0 )

-	return QString::null;

+    if ( !chars ) return QString::null;

+    if ( chars && (chars[0]=='\0' || len==0) ) {

+        QString blank;

+        blank.setLength(0);

+        return blank;

+    }

+

+    QString r;

+ 

+    const unsigned char * c = (const unsigned char *)chars;

+    int i;

+

+    for ( i = 0; i < len; i++ ) 

+        if ( c[i] == '\0' ) len = i;

-    return QString::fromLatin1(chars, len);

+    if( len > 0 ) {

+        r.setUnicode(0, len);

+        QChar* uc = (QChar*)r.unicode(); // const_cast

+

+        for ( i = 0; i < len; i++ )

+            uc[i] = QChar( c[i], 0 );

+    }

+    return r;

 }

diff -Naur qt-x11-free-3.3.8b-orig/src/codecs/qutfcodec.cpp qt-x11-free-3.3.8b/src/codecs/qutfcodec.cpp

--- qt-x11-free-3.3.8d/src/codecs/qutfcodec.cpp~	2011-11-16 18:51:21.000000000 +0400

+++ qt-x11-free-3.3.8d/src/codecs/qutfcodec.cpp	2011-11-16 18:54:06.000000000 +0400

@@ -303,6 +303,16 @@ public:

     QString toUnicode(const char* chars, int len)

     {

 	QString result;

+        if (!chars) return QString::null;

+        if (chars && (chars[0]=='\0' || len==0)) {

+            result.setLength(0);

+            return result;

+        }

+        if (!chars) return QString::null;

+        if (chars && (chars[0]=='\0' || len==0)) {

+            result.setLength(0);

+            return result;

+        }

 	result.setLength( len + 1 ); // worst case

 	QChar *qch = (QChar *)result.unicode();

 	QChar ch;