QCanBusFrame::toString(): Add one more space around the length field

This limits the three fields CAN-ID, length and data better.

SocketCAN's candump does it this way and with this change
canbusutil get's more compatible to candump.

This function is new in 5.8, so there is no behavior change
for existing code outside Qt.

Change-Id: Ifc26cb7584a572d7aef91763242e7def909a6083
Reviewed-by: Rolf Eike Beer <eb@emlix.com>
Reviewed-by: Andreas Wilhelm <aw@emlix.com>
Reviewed-by: Denis Shienkov <denis.shienkov@gmail.com>
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>

4 files changed, 22 insertions, 19 deletions

diff --git a/examples/serialbus/can/mainwindow.ui b/examples/serialbus/can/mainwindow.ui
index 4a3fcf9..b4b8c6c 100644
--- a/examples/serialbus/can/mainwindow.ui
+++ b/examples/serialbus/can/mainwindow.ui
@@ -143,7 +143,7 @@ Otherwise, the standard format with 11 bit idenfier is used.</string>
           <enum>QFrame::StyledPanel</enum>
          </property>
          <property name="text">
-          <string>Timestamp         CAN-ID  DLC Data</string>
+          <string>Timestamp         CAN-ID   DLC  Data</string>
          </property>
         </widget>
        </item>
diff --git a/src/serialbus/qcanbusframe.cpp b/src/serialbus/qcanbusframe.cpp
index fde355f..b030c9a 100644
--- a/src/serialbus/qcanbusframe.cpp
+++ b/src/serialbus/qcanbusframe.cpp
@@ -288,12 +288,12 @@ QT_BEGIN_NAMESPACE
     Typical outputs are:
 
     \code
-        (Error)                                - error frame
-             7FF  [1] 01                       - data frame with standard identifier
-        1FFFFFFF  [8] 01 23 45 67 89 AB CD EF  - data frame with extended identifier
-             400 [10] 01 23 45 67 ... EF 01 23 - CAN FD frame
-             123  [5] Remote Request           - remote frame with standard identifier
-        00000234  [0] Remote Request           - remote frame with extended identifier
+        (Error)                                  - error frame
+             7FF   [1]  01                       - data frame with standard identifier
+        1FFFFFFF   [8]  01 23 45 67 89 AB CD EF  - data frame with extended identifier
+             400  [10]  01 23 45 67 ... EF 01 23 - CAN FD frame
+             123   [5]  Remote Request           - remote frame with standard identifier
+        00000234   [0]  Remote Request           - remote frame with extended identifier
     \endcode
 
     \since 5.8
diff --git a/src/serialbus/qcanbusframe.h b/src/serialbus/qcanbusframe.h
index e6f4d28..f8b1b06 100644
--- a/src/serialbus/qcanbusframe.h
+++ b/src/serialbus/qcanbusframe.h
@@ -206,17 +206,20 @@ public:
             return QStringLiteral("(Unknown)");
 
         const char *idFormat = hasExtendedFrameFormat() ? "%08X" : "     %03X";
-        const char *dlcFormat = payload().size() < 10 ? "  [%d]" : " [%d]";
+        const char *dlcFormat = payload().size() < 10 ? "   [%d]" : "  [%d]";
         QString result;
         result.append(QString::asprintf(idFormat, static_cast<uint>(frameId())));
         result.append(QString::asprintf(dlcFormat, payload().size()));
 
         if (type == RemoteRequestFrame) {
-            result.append(QLatin1String(" Remote Request"));
+            result.append(QLatin1String("  Remote Request"));
         } else {
             const QByteArray data = payload().toHex().toUpper();
             const QLatin1String l1(data.data(), data.size());
-            for (int i = 0, e = data.size(); i < e; i += 2) {
+            const int length = data.size();
+            if (length)
+                result.append(QLatin1Char(' '));
+            for (int i = 0; i < length; i += 2) {
                 result.append(QLatin1Char(' '));
                 result.append(l1.mid(i, 2));
             }
diff --git a/tests/auto/qcanbusframe/tst_qcanbusframe.cpp b/tests/auto/qcanbusframe/tst_qcanbusframe.cpp
index 3a199ec..f8b3781 100644
--- a/tests/auto/qcanbusframe/tst_qcanbusframe.cpp
+++ b/tests/auto/qcanbusframe/tst_qcanbusframe.cpp
@@ -242,39 +242,39 @@ void tst_QCanBusFrame::tst_toString_data()
     QTest::newRow("remote request frame")
             << QCanBusFrame::RemoteRequestFrame << 0x123u << false
             << QByteArray::fromHex("01") // fake data to get a DLC > 0
-            << QString("     123  [1] Remote Request");
+            << QString("     123   [1]  Remote Request");
     QTest::newRow("data frame min std id")
             << QCanBusFrame::DataFrame << 0x0u << false
             << QByteArray()
-            << QString("     000  [0]");
+            << QString("     000   [0]");
     QTest::newRow("data frame max std id")
             << QCanBusFrame::DataFrame << 0x7FFu << false
             << QByteArray()
-            << QString("     7FF  [0]");
+            << QString("     7FF   [0]");
     QTest::newRow("data frame min ext id")
             << QCanBusFrame::DataFrame << 0x0u << true
             << QByteArray()
-            << QString("00000000  [0]");
+            << QString("00000000   [0]");
     QTest::newRow("data frame max ext id")
             << QCanBusFrame::DataFrame << 0x1FFFFFFFu << true
             << QByteArray()
-            << QString("1FFFFFFF  [0]");
+            << QString("1FFFFFFF   [0]");
     QTest::newRow("data frame minimal size")
             << QCanBusFrame::DataFrame << 0x7FFu << false
             << QByteArray::fromHex("01")
-            << QString("     7FF  [1] 01");
+            << QString("     7FF   [1]  01");
     QTest::newRow("data frame maximal size")
             << QCanBusFrame::DataFrame << 0x1FFFFFFFu << true
             << QByteArray::fromHex("0123456789ABCDEF")
-            << QString("1FFFFFFF  [8] 01 23 45 67 89 AB CD EF");
+            << QString("1FFFFFFF   [8]  01 23 45 67 89 AB CD EF");
     QTest::newRow("short data frame FD")
             << QCanBusFrame::DataFrame << 0x123u << false
             << QByteArray::fromHex("001122334455667788")
-            << QString("     123  [9] 00 11 22 33 44 55 66 77 88");
+            << QString("     123   [9]  00 11 22 33 44 55 66 77 88");
     QTest::newRow("long data frame FD")
             << QCanBusFrame::DataFrame << 0x123u << false
             << QByteArray::fromHex("00112233445566778899")
-            << QString("     123 [10] 00 11 22 33 44 55 66 77 88 99");
+            << QString("     123  [10]  00 11 22 33 44 55 66 77 88 99");
 }
 
 void tst_QCanBusFrame::tst_toString()