Add support for IPv6 parsing and reconstructing the address

Similarly, only test against the libc function on Linux, as other OS
sometimes have different behaviour.

Change-Id: I9b8ef9a3d660a59882396d695202865ca307e528
Reviewed-by: João Abecasis <joao.abecasis@nokia.com>
Reviewed-by: Shane Kearns <shane.kearns@accenture.com>

3 files changed, 503 insertions, 2 deletions

diff --git a/src/corelib/io/qipaddress.cpp b/src/corelib/io/qipaddress.cpp
index b8871fe8b9..e996c8665c 100644
--- a/src/corelib/io/qipaddress.cpp
+++ b/src/corelib/io/qipaddress.cpp
@@ -71,6 +71,7 @@ static bool checkedToAscii(Buffer &buffer, const QChar *begin, const QChar *end)
     return true;
 }
 
+static bool parseIp4Internal(IPv4Address &address, const char *ptr, bool acceptLeadingZero);
 bool parseIp4(IPv4Address &address, const QChar *begin, const QChar *end)
 {
     Q_ASSERT(begin != end);
@@ -78,10 +79,19 @@ bool parseIp4(IPv4Address &address, const QChar *begin, const QChar *end)
     if (!checkedToAscii(buffer, begin, end))
         return false;
 
-    int dotCount = 0;
-    address = 0;
     const char *ptr = buffer.data();
+    return parseIp4Internal(address, ptr, true);
+}
+
+static bool parseIp4Internal(IPv4Address &address, const char *ptr, bool acceptLeadingZero)
+{
+    address = 0;
+    int dotCount = 0;
     while (dotCount < 4) {
+        if (!acceptLeadingZero && *ptr == '0' &&
+                ptr[1] != '.' && ptr[1] != '\0')
+            return false;
+
         const char *endptr;
         bool ok;
         quint64 ll = qstrtoull(ptr, &endptr, 0, &ok);
@@ -127,5 +137,208 @@ void toString(QString &appendTo, IPv4Address address)
                 % number(address);
 }
 
+bool parseIp6(IPv6Address &address, const QChar *begin, const QChar *end)
+{
+    Q_ASSERT(begin != end);
+    Buffer buffer;
+    if (!checkedToAscii(buffer, begin, end))
+        return false;
+
+    const char *ptr = buffer.data();
+
+    // count the colons
+    int colonCount = 0;
+    int dotCount = 0;
+    while (*ptr) {
+        if (*ptr == ':')
+            ++colonCount;
+        if (*ptr == '.')
+            ++dotCount;
+        ++ptr;
+    }
+    // IPv4-in-IPv6 addresses are stricter in what they accept
+    if (dotCount != 0 && dotCount != 3)
+        return false;
+
+    memset(address, 0, sizeof address);
+    if (colonCount == 2 && end - begin == 2) // "::"
+        return true;
+
+    // if there's a double colon ("::"), this is how many zeroes it means
+    int zeroWordsToFill;
+    ptr = buffer.data();
+
+    // there are two cases where 8 colons are allowed: at the ends
+    // so test that before the colon-count test
+    if ((ptr[0] == ':' && ptr[1] == ':') ||
+            (ptr[end - begin - 2] == ':' && ptr[end - begin - 1] == ':')) {
+        zeroWordsToFill = 9 - colonCount;
+    } else if (colonCount < 2 || colonCount > 7) {
+        return false;
+    } else {
+        zeroWordsToFill = 8 - colonCount;
+    }
+    if (dotCount)
+        --zeroWordsToFill;
+
+    int pos = 0;
+    while (pos < 15) {
+        const char *endptr;
+        bool ok;
+        quint64 ll = qstrtoull(ptr, &endptr, 16, &ok);
+        quint16 x = ll;
+
+        if (ptr == endptr) {
+            // empty field, we hope it's "::"
+            if (zeroWordsToFill < 1)
+                return false;
+            if (pos == 0 || pos == colonCount * 2) {
+                if (ptr[0] == '\0' || ptr[1] != ':')
+                    return false;
+                ++ptr;
+            }
+            pos += zeroWordsToFill * 2;
+            zeroWordsToFill = 0;
+            ++ptr;
+            continue;
+        }
+        if (!ok || ll != x)
+            return false;
+
+        if (*endptr == '.') {
+            // this could be an IPv4 address
+            // it's only valid in the last element
+            if (pos != 12)
+                return false;
+
+            IPv4Address ip4;
+            if (!parseIp4Internal(ip4, ptr, false))
+                return false;
+
+            address[12] = ip4 >> 24;
+            address[13] = ip4 >> 16;
+            address[14] = ip4 >> 8;
+            address[15] = ip4;
+            return true;
+        }
+
+        address[pos++] = x >> 8;
+        address[pos++] = x & 0xff;
+
+        if (*endptr == '\0')
+            break;
+        if (*endptr != ':')
+            return false;
+        ptr = endptr + 1;
+    }
+    return pos == 16;
+}
+
+static inline QChar toHex(uchar c)
+{
+    return ushort(c > 9 ? c + 'a' - 0xA : c + '0');
+}
+
+void toString(QString &appendTo, IPv6Address address)
+{
+    // the longest IPv6 address possible is:
+    //   "1111:2222:3333:4444:5555:6666:255.255.255.255"
+    // however, this function never generates that. The longest it does
+    // generate without an IPv4 address is:
+    //   "1111:2222:3333:4444:5555:6666:7777:8888"
+    // and the longest with an IPv4 address is:
+    //   "::ffff:255.255.255.255"
+    static const int Ip6AddressMaxLen = sizeof "1111:2222:3333:4444:5555:6666:7777:8888";
+    static const int Ip6WithIp4AddressMaxLen = sizeof "::ffff:255.255.255.255";
+
+    // check for the special cases
+    const quint64 zeroes[] = { 0, 0 };
+    bool embeddedIp4 = false;
+
+    // we consider embedded IPv4 for:
+    //  ::ffff:x.x.x.x
+    //  ::x.x.x.y  except if the x are 0 too
+    if (memcmp(address, zeroes, 10) == 0) {
+        if (address[10] == 0xff && address[11] == 0xff) {
+            embeddedIp4 = true;
+        } else if (address[10] == 0 && address[11] == 0) {
+            if (address[12] != 0 || address[13] != 0 || address[14] != 0) {
+                embeddedIp4 = true;
+            } else if (address[15] == 0) {
+                appendTo.append(QLatin1String("::"));
+                return;
+            }
+        }
+    }
+
+    // QString::reserve doesn't shrink, so it's fine to us
+    appendTo.reserve(appendTo.size() +
+                     embeddedIp4 ? Ip6WithIp4AddressMaxLen : Ip6AddressMaxLen);
+
+    // for finding where to place the "::"
+    int zeroRunLength = 0; // in octets
+    int zeroRunOffset = 0; // in octets
+    for (int i = 0; i < 16; i += 2) {
+        if (address[i] == 0 && address[i + 1] == 0) {
+            // found a zero, scan forward to see how many more there are
+            int j;
+            for (j = i; j < 16; j += 2) {
+                if (address[j] != 0 || address[j+1] != 0)
+                    break;
+            }
+
+            if (j - i > zeroRunLength) {
+                zeroRunLength = j - i;
+                zeroRunOffset = i;
+                i = j;
+            }
+        }
+    }
+
+    const QChar colon = ushort(':');
+    if (zeroRunLength < 4)
+        zeroRunOffset = -1;
+    else if (zeroRunOffset == 0)
+        appendTo.append(colon);
+
+    for (int i = 0; i < 16; i += 2) {
+        if (i == zeroRunOffset) {
+            appendTo.append(colon);
+            i += zeroRunLength - 2;
+            continue;
+        }
+
+        if (i == 12 && embeddedIp4) {
+            IPv4Address ip4 = address[12] << 24 |
+                              address[13] << 16 |
+                              address[14] << 8 |
+                              address[15];
+            toString(appendTo, ip4);
+            return;
+        }
+
+        if (address[i]) {
+            if (address[i] >> 4) {
+                appendTo.append(toHex(address[i] >> 4));
+                appendTo.append(toHex(address[i] & 0xf));
+                appendTo.append(toHex(address[i + 1] >> 4));
+                appendTo.append(toHex(address[i + 1] & 0xf));
+            } else if (address[i] & 0xf) {
+                appendTo.append(toHex(address[i] & 0xf));
+                appendTo.append(toHex(address[i + 1] >> 4));
+                appendTo.append(toHex(address[i + 1] & 0xf));
+            }
+        } else if (address[i + 1] >> 4) {
+            appendTo.append(toHex(address[i + 1] >> 4));
+            appendTo.append(toHex(address[i + 1] & 0xf));
+        } else {
+            appendTo.append(toHex(address[i + 1] & 0xf));
+        }
+
+        if (i != 14)
+            appendTo.append(colon);
+    }
+}
+
 }
 QT_END_NAMESPACE
diff --git a/src/corelib/io/qipaddress_p.h b/src/corelib/io/qipaddress_p.h
index f3bcf76424..834f9557f3 100644
--- a/src/corelib/io/qipaddress_p.h
+++ b/src/corelib/io/qipaddress_p.h
@@ -60,9 +60,12 @@ QT_BEGIN_NAMESPACE
 namespace QIPAddressUtils {
 
 typedef quint32 IPv4Address;
+typedef quint8 IPv6Address[16];
 
 Q_CORE_EXPORT bool parseIp4(IPv4Address &address, const QChar *begin, const QChar *end);
+Q_CORE_EXPORT bool parseIp6(IPv6Address &address, const QChar *begin, const QChar *end);
 Q_CORE_EXPORT void toString(QString &appendTo, IPv4Address address);
+Q_CORE_EXPORT void toString(QString &appendTo, IPv6Address address);
 
 } // namespace
 
diff --git a/tests/auto/corelib/io/qipaddress/tst_qipaddress.cpp b/tests/auto/corelib/io/qipaddress/tst_qipaddress.cpp
index 73cbbdea0e..bad18fabef 100644
--- a/tests/auto/corelib/io/qipaddress/tst_qipaddress.cpp
+++ b/tests/auto/corelib/io/qipaddress/tst_qipaddress.cpp
@@ -60,7 +60,65 @@ private Q_SLOTS:
     void invalidParseIp4();
     void ip4ToString_data();
     void ip4ToString();
+
+    void parseIp6_data();
+    void parseIp6();
+    void invalidParseIp6_data();
+    void invalidParseIp6();
+    void ip6ToString_data();
+    void ip6ToString();
+};
+
+struct Ip6
+{
+    QIPAddressUtils::IPv6Address u8;
+    Ip6() { *this = Ip6(0,0,0,0, 0,0,0,0); }
+    Ip6(quint16 p1, quint16 p2, quint16 p3, quint16 p4,
+         quint16 p5, quint16 p6, quint16 p7, quint16 p8)
+    {
+        u8[0] = p1 >> 8;
+        u8[2] = p2 >> 8;
+        u8[4] = p3 >> 8;
+        u8[6] = p4 >> 8;
+        u8[8] = p5 >> 8;
+        u8[10] = p6 >> 8;
+        u8[12] = p7 >> 8;
+        u8[14] = p8 >> 8;
+
+        u8[1] = p1 & 0xff;
+        u8[3] = p2 & 0xff;
+        u8[5] = p3 & 0xff;
+        u8[7] = p4 & 0xff;
+        u8[9] = p5 & 0xff;
+        u8[11] = p6 & 0xff;
+        u8[13] = p7 & 0xff;
+        u8[15] = p8 & 0xff;
+    }
+
+    bool operator==(const Ip6 &other) const
+    { return memcmp(u8, other.u8, sizeof u8) == 0; }
 };
+Q_DECLARE_METATYPE(Ip6)
+
+QT_BEGIN_NAMESPACE
+namespace QTest {
+    template<>
+    char *toString(const Ip6 &ip6)
+    {
+        char buf[sizeof "1111:2222:3333:4444:5555:6666:7777:8888" + 2];
+        sprintf(buf, "%x:%x:%x:%x:%x:%x:%x:%x",
+                ip6.u8[0] << 8 | ip6.u8[1],
+                ip6.u8[2] << 8 | ip6.u8[3],
+                ip6.u8[4] << 8 | ip6.u8[5],
+                ip6.u8[6] << 8 | ip6.u8[7],
+                ip6.u8[8] << 8 | ip6.u8[9],
+                ip6.u8[10] << 8 | ip6.u8[11],
+                ip6.u8[12] << 8 | ip6.u8[13],
+                ip6.u8[14] << 8 | ip6.u8[15]);
+        return strdup(buf);
+    }
+}
+QT_END_NAMESPACE
 
 void tst_QIpAddress::parseIp4_data()
 {
@@ -213,6 +271,233 @@ void tst_QIpAddress::ip4ToString()
     QCOMPARE(result, expected);
 }
 
+void tst_QIpAddress::parseIp6_data()
+{
+    qRegisterMetaType<Ip6>();
+    QTest::addColumn<QString>("address");
+    QTest::addColumn<Ip6>("expected");
+
+    // 7 colons, no ::
+    QTest::newRow("0:0:0:0:0:0:0:0") << "0:0:0:0:0:0:0:0" << Ip6(0,0,0,0,0,0,0,0);
+    QTest::newRow("0:0:0:0:0:0:0:1") << "0:0:0:0:0:0:0:1" << Ip6(0,0,0,0,0,0,0,1);
+    QTest::newRow("0:0:0:0:0:0:1:1") << "0:0:0:0:0:0:1:1" << Ip6(0,0,0,0,0,0,1,1);
+    QTest::newRow("0:0:0:0:0:0:0:103") << "0:0:0:0:0:0:0:103" << Ip6(0,0,0,0,0,0,0,0x103);
+    QTest::newRow("1:2:3:4:5:6:7:8") << "1:2:3:4:5:6:7:8" << Ip6(1,2,3,4,5,6,7,8);
+    QTest::newRow("ffee:ddcc:bbaa:9988:7766:5544:3322:1100")
+            << "ffee:ddcc:bbaa:9988:7766:5544:3322:1100"
+            << Ip6(0xffee, 0xddcc, 0xbbaa, 0x9988, 0x7766, 0x5544, 0x3322, 0x1100);
+
+    // too many zeroes
+    QTest::newRow("0:0:0:0:0:0:0:00103") << "0:0:0:0:0:0:0:00103" << Ip6(0,0,0,0,0,0,0,0x103);
+
+    // double-colon
+    QTest::newRow("::1:2:3:4:5:6:7") << "::1:2:3:4:5:6:7" << Ip6(0,1,2,3,4,5,6,7);
+    QTest::newRow("1:2:3:4:5:6:7::") << "1:2:3:4:5:6:7::" << Ip6(1,2,3,4,5,6,7,0);
+
+    QTest::newRow("1::2:3:4:5:6:7") << "1::2:3:4:5:6:7" << Ip6(1,0,2,3,4,5,6,7);
+    QTest::newRow("1:2::3:4:5:6:7") << "1:2::3:4:5:6:7" << Ip6(1,2,0,3,4,5,6,7);
+    QTest::newRow("1:2:3::4:5:6:7") << "1:2:3::4:5:6:7" << Ip6(1,2,3,0,4,5,6,7);
+    QTest::newRow("1:2:3:4::5:6:7") << "1:2:3:4::5:6:7" << Ip6(1,2,3,4,0,5,6,7);
+    QTest::newRow("1:2:3:4:5::6:7") << "1:2:3:4:5::6:7" << Ip6(1,2,3,4,5,0,6,7);
+    QTest::newRow("1:2:3:4:5:6::7") << "1:2:3:4:5:6::7" << Ip6(1,2,3,4,5,6,0,7);
+
+    QTest::newRow("::1:2:3:4:5:6") << "::1:2:3:4:5:6" << Ip6(0,0,1,2,3,4,5,6);
+    QTest::newRow("1:2:3:4:5:6::") << "1:2:3:4:5:6::" << Ip6(1,2,3,4,5,6,0,0);
+
+    QTest::newRow("1::2:3:4:5:6") << "1::2:3:4:5:6" << Ip6(1,0,0,2,3,4,5,6);
+    QTest::newRow("1:2::3:4:5:6") << "1:2::3:4:5:6" << Ip6(1,2,0,0,3,4,5,6);
+    QTest::newRow("1:2:3::4:5:6") << "1:2:3::4:5:6" << Ip6(1,2,3,0,0,4,5,6);
+    QTest::newRow("1:2:3:4::5:6") << "1:2:3:4::5:6" << Ip6(1,2,3,4,0,0,5,6);
+    QTest::newRow("1:2:3:4:5::6") << "1:2:3:4:5::6" << Ip6(1,2,3,4,5,0,0,6);
+
+    QTest::newRow("::1:2:3:4:5") << "::1:2:3:4:5" << Ip6(0,0,0,1,2,3,4,5);
+    QTest::newRow("1:2:3:4:5::") << "1:2:3:4:5::" << Ip6(1,2,3,4,5,0,0,0);
+
+    QTest::newRow("1::2:3:4:5") << "1::2:3:4:5" << Ip6(1,0,0,0,2,3,4,5);
+    QTest::newRow("1:2::3:4:5") << "1:2::3:4:5" << Ip6(1,2,0,0,0,3,4,5);
+    QTest::newRow("1:2:3::4:5") << "1:2:3::4:5" << Ip6(1,2,3,0,0,0,4,5);
+    QTest::newRow("1:2:3:4::5") << "1:2:3:4::5" << Ip6(1,2,3,4,0,0,0,5);
+
+    QTest::newRow("::1:2:3:4") << "::1:2:3:4" << Ip6(0,0,0,0,1,2,3,4);
+    QTest::newRow("1:2:3:4::") << "1:2:3:4::" << Ip6(1,2,3,4,0,0,0,0);
+
+    QTest::newRow("1::2:3:4") << "1::2:3:4" << Ip6(1,0,0,0,0,2,3,4);
+    QTest::newRow("1:2::3:4") << "1:2::3:4" << Ip6(1,2,0,0,0,0,3,4);
+    QTest::newRow("1:2:3::4") << "1:2:3::4" << Ip6(1,2,3,0,0,0,0,4);
+
+    QTest::newRow("::1:2:3") << "::1:2:3" << Ip6(0,0,0,0,0,1,2,3);
+    QTest::newRow("1:2:3::") << "1:2:3::" << Ip6(1,2,3,0,0,0,0,0);
+
+    QTest::newRow("1::2:3") << "1::2:3" << Ip6(1,0,0,0,0,0,2,3);
+    QTest::newRow("1:2::3") << "1:2::3" << Ip6(1,2,0,0,0,0,0,3);
+
+    QTest::newRow("::1:2") << "::1:2" << Ip6(0,0,0,0,0,0,1,2);
+    QTest::newRow("1:2::") << "1:2::" << Ip6(1,2,0,0,0,0,0,0);
+
+    QTest::newRow("1::2") << "1::2" << Ip6(1,0,0,0,0,0,0,2);
+
+    QTest::newRow("::1") << "::1" << Ip6(0,0,0,0,0,0,0,1);
+    QTest::newRow("1::") << "1::" << Ip6(1,0,0,0,0,0,0,0);
+
+    QTest::newRow("::") << "::" << Ip6(0,0,0,0,0,0,0,0);
+
+    // embedded IPv4
+    QTest::newRow("1:2:3:4:5:6:10.0.16.1") << "1:2:3:4:5:6:10.0.16.1" << Ip6(1,2,3,4,5,6,0xa00,0x1001);
+    QTest::newRow("1::10.0.16.1") << "1::10.0.16.1" << Ip6(1,0,0,0,0,0,0xa00,0x1001);
+    QTest::newRow("::10.0.16.1") << "::10.0.16.1" << Ip6(0,0,0,0,0,0,0xa00,0x1001);
+    QTest::newRow("::0.0.0.0") << "::0.0.0.0" << Ip6(0,0,0,0,0,0,0,0);
+}
+
+void tst_QIpAddress::parseIp6()
+{
+    QFETCH(QString, address);
+    QFETCH(Ip6, expected);
+
+#if defined(__GLIBC__) && defined(AF_INET6)
+    Ip6 inet_result;
+    bool inet_ok = inet_pton(AF_INET6, address.toLatin1(), &inet_result.u8);
+    QVERIFY(inet_ok);
+    QCOMPARE(inet_result, expected);
+#endif
+
+    Ip6 result;
+    bool ok = QIPAddressUtils::parseIp6(result.u8, address.constBegin(), address.constEnd());
+    QVERIFY(ok);
+    QCOMPARE(result, expected);
+}
+
+void tst_QIpAddress::invalidParseIp6_data()
+{
+    QTest::addColumn<QString>("address");
+
+    // too many colons
+    QTest::newRow("0:0:0:0::0:0:0:0") << "0:0:0:0::0:0:0:0";
+    QTest::newRow("0:::") << "0:::"; QTest::newRow(":::0") << ":::0";
+    QTest::newRow("16:::::::::::::::::::::::") << "16:::::::::::::::::::::::";
+
+    // non-hex
+    QTest::newRow("a:b:c:d:e:f:g:h") << "a:b:c:d:e:f:g:h";
+
+    // too big number
+    QTest::newRow("0:0:0:0:0:0:0:10103") << "0:0:0:0:0:0:0:10103";
+
+    // too short
+    QTest::newRow("0:0:0:0:0:0:0:") << "0:0:0:0:0:0:0:";
+    QTest::newRow("0:0:0:0:0:0:0") << "0:0:0:0:0:0:0";
+    QTest::newRow("0:0:0:0:0:0:") << "0:0:0:0:0:0:";
+    QTest::newRow("0:0:0:0:0:0") << "0:0:0:0:0:0";
+    QTest::newRow("0:0:0:0:0:") << "0:0:0:0:0:";
+    QTest::newRow("0:0:0:0:0") << "0:0:0:0:0";
+    QTest::newRow("0:0:0:0:") << "0:0:0:0:";
+    QTest::newRow("0:0:0:0") << "0:0:0:0";
+    QTest::newRow("0:0:0:") << "0:0:0:";
+    QTest::newRow("0:0:0") << "0:0:0";
+    QTest::newRow("0:0:") << "0:0:";
+    QTest::newRow("0:0") << "0:0";
+    QTest::newRow("0:") << "0:";
+    QTest::newRow("0") << "0";
+    QTest::newRow(":0") << ":0";
+    QTest::newRow(":0:0") << ":0:0";
+    QTest::newRow(":0:0:0") << ":0:0:0";
+    QTest::newRow(":0:0:0:0") << ":0:0:0:0";
+    QTest::newRow(":0:0:0:0:0") << ":0:0:0:0:0";
+    QTest::newRow(":0:0:0:0:0:0") << ":0:0:0:0:0:0";
+    QTest::newRow(":0:0:0:0:0:0:0") << ":0:0:0:0:0:0:0";
+
+    // IPv4
+    QTest::newRow("1.2.3.4") << "1.2.3.4";
+
+    // embedded IPv4 in the wrong position
+    QTest::newRow("1.2.3.4::") << "1.2.3.4::";
+    QTest::newRow("f:1.2.3.4::") << "f:1.2.3.4::";
+    QTest::newRow("f:e:d:c:b:1.2.3.4:0") << "f:e:d:c:b:1.2.3.4:0";
+
+    // bad embedded IPv4
+    QTest::newRow("::1.2.3") << "::1.2.3";
+    QTest::newRow("::1.2.257") << "::1.2.257";
+    QTest::newRow("::1.2") << "::1.2";
+    QTest::newRow("::0250.0x10101") << "::0250.0x10101";
+    QTest::newRow("::1.2.3.0250") << "::1.2.3.0250";
+    QTest::newRow("::1.2.3.0xff") << "::1.2.3.0xff";
+    QTest::newRow("::1.2.3.07") << "::1.2.3.07";
+    QTest::newRow("::1.2.3.010") << "::1.2.3.010";
+
+    // separated by something else
+    QTest::newRow("1.2.3.4.5.6.7.8") << "1.2.3.4.5.6.7.8";
+    QTest::newRow("1,2,3,4,5,6,7,8") << "1,2,3,4,5,6,7,8";
+    QTest::newRow("1..2") << "1..2";
+    QTest::newRow("1:.2") << "1:.2";
+    QTest::newRow("1.:2") << "1.:2";
+}
+
+void tst_QIpAddress::invalidParseIp6()
+{
+    QFETCH(QString, address);
+
+#if defined(__GLIBC__) && defined(AF_INET6)
+    Ip6 inet_result;
+    bool inet_ok = inet_pton(AF_INET6, address.toLatin1(), &inet_result.u8);
+    QVERIFY(!inet_ok);
+#endif
+
+    Ip6 result;
+    bool ok = QIPAddressUtils::parseIp6(result.u8, address.constBegin(), address.constEnd());
+    QVERIFY(!ok);
+}
+
+void tst_QIpAddress::ip6ToString_data()
+{
+    qRegisterMetaType<Ip6>();
+    QTest::addColumn<Ip6>("ip");
+    QTest::addColumn<QString>("expected");
+
+    QTest::newRow("1:2:3:4:5:6:7:8") << Ip6(1,2,3,4,5,6,7,8) << "1:2:3:4:5:6:7:8";
+    QTest::newRow("1:2:3:4:5:6:7:88") << Ip6(1,2,3,4,5,6,7,0x88) << "1:2:3:4:5:6:7:88";
+    QTest::newRow("1:2:3:4:5:6:7:888") << Ip6(1,2,3,4,5,6,7,0x888) << "1:2:3:4:5:6:7:888";
+    QTest::newRow("1:2:3:4:5:6:7:8888") << Ip6(1,2,3,4,5,6,7,0x8888) << "1:2:3:4:5:6:7:8888";
+    QTest::newRow("1:2:3:4:5:6:7:8880") << Ip6(1,2,3,4,5,6,7,0x8880) << "1:2:3:4:5:6:7:8880";
+    QTest::newRow("1:2:3:4:5:6:7:8808") << Ip6(1,2,3,4,5,6,7,0x8808) << "1:2:3:4:5:6:7:8808";
+    QTest::newRow("1:2:3:4:5:6:7:8088") << Ip6(1,2,3,4,5,6,7,0x8088) << "1:2:3:4:5:6:7:8088";
+
+    QTest::newRow("1:2:3:4:5:6:7:0") << Ip6(1,2,3,4,5,6,7,0) << "1:2:3:4:5:6:7:0";
+    QTest::newRow("0:1:2:3:4:5:6:7") << Ip6(0,1,2,3,4,5,6,7) << "0:1:2:3:4:5:6:7";
+
+    QTest::newRow("1:2:3:4:5:6::") << Ip6(1,2,3,4,5,6,0,0) << "1:2:3:4:5:6::";
+    QTest::newRow("::1:2:3:4:5:6") << Ip6(0,0,1,2,3,4,5,6) << "::1:2:3:4:5:6";
+    QTest::newRow("1:0:0:2::3") << Ip6(1,0,0,2,0,0,0,3) << "1:0:0:2::3";
+    QTest::newRow("1:::2:0:0:3") << Ip6(1,0,0,0,2,0,0,3) << "1::2:0:0:3";
+    QTest::newRow("1::2:0:0:0") << Ip6(1,0,0,0,2,0,0,0) << "1::2:0:0:0";
+    QTest::newRow("0:0:0:1::") << Ip6(0,0,0,1,0,0,0,0) << "0:0:0:1::";
+    QTest::newRow("::1:0:0:0") << Ip6(0,0,0,0,1,0,0,0) << "::1:0:0:0";
+    QTest::newRow("ff02::1") << Ip6(0xff02,0,0,0,0,0,0,1) << "ff02::1";
+    QTest::newRow("1::1") << Ip6(1,0,0,0,0,0,0,1) << "1::1";
+    QTest::newRow("::1") << Ip6(0,0,0,0,0,0,0,1) << "::1";
+    QTest::newRow("1::") << Ip6(1,0,0,0,0,0,0,0) << "1::";
+    QTest::newRow("::") << Ip6(0,0,0,0,0,0,0,0) << "::";
+
+    QTest::newRow("::1.2.3.4") << Ip6(0,0,0,0,0,0,0x102,0x304) << "::1.2.3.4";
+    QTest::newRow("::ffff:1.2.3.4") << Ip6(0,0,0,0,0,0xffff,0x102,0x304) << "::ffff:1.2.3.4";
+}
+
+void tst_QIpAddress::ip6ToString()
+{
+    QFETCH(Ip6, ip);
+    QFETCH(QString, expected);
+
+#if defined(__GLIBC__) && defined(AF_INET6)
+    {
+        char buf[INET6_ADDRSTRLEN];
+        bool ok = inet_ntop(AF_INET6, ip.u8, buf, sizeof buf) != 0;
+        QVERIFY(ok);
+        QCOMPARE(QString(buf), expected);
+    }
+#endif
+
+    QString result;
+    QIPAddressUtils::toString(result, ip.u8);
+    QCOMPARE(result, expected);
+}
+
 QTEST_APPLESS_MAIN(tst_QIpAddress)
 
 #include "tst_qipaddress.moc"