perf(qmltermwidget): skip the tokenizer for plain text and move screen lines on scroll

qmltermwidget/lib/Emulation.cpp

@@ -253,13 +253,26 @@ void Emulation::receiveData(const char* text, int length)
      * U+10FFFF
      * https://unicodebook.readthedocs.io/unicode_encodings.html#surrogates
      */
-    QByteArray ba(text, length);
-    QString str = _toUtf16(ba);
-    std::wstring unicodeText = str.toStdWString();
+    const QString str = _toUtf16(QByteArrayView(text, length));
 
-    //send characters to terminal emulator
-    for (size_t i=0;i<unicodeText.length();i++)
-        receiveChar(unicodeText[i]);
+    //send characters to terminal emulator; an unpaired surrogate becomes U+FFFD
+    const QChar* unit = str.constData();
+    const QChar* end = unit + str.size();
+    while (unit < end)
+    {
+        const QChar current = *unit++;
+        if (Q_UNLIKELY(current.isSurrogate()))
+        {
+            if (current.isHighSurrogate() && unit < end && unit->isLowSurrogate())
+                receiveChar(wchar_t(QChar::surrogateToUcs4(current, *unit++)));
+            else
+                receiveChar(wchar_t(QChar::ReplacementCharacter));
+        }
+        else
+        {
+            receiveChar(wchar_t(current.unicode()));
+        }
+    }
 
     //look for z-modem indicator
     //-- someone who understands more about z-modems that I do may be able to move

qmltermwidget/lib/History.cpp

@@ -309,7 +309,12 @@ void HistoryScrollBuffer::addCellsVector(const QVector<Character>& cells)
         _head = 0;
     }
 
-    _historyBuffer[bufferIndex(_usedLines-1)] = cells;
+    // Screen lines keep a whole row of capacity to write into; a history line
+    // keeps only the cells it holds.
+    if (cells.capacity() > cells.size())
+        _historyBuffer[bufferIndex(_usedLines-1)] = QVector<Character>(cells.cbegin(), cells.cend());
+    else
+        _historyBuffer[bufferIndex(_usedLines-1)] = cells;
     _wrappedLine[bufferIndex(_usedLines-1)] = false;
 }
 void HistoryScrollBuffer::addCells(const Character a[], int count)

qmltermwidget/lib/Screen.cpp

@@ -315,11 +315,6 @@ void Screen::restoreMode(int m)
     currentModes[m] = savedModes[m];
 }
 
-bool Screen::getMode(int m) const
-{
-    return currentModes[m];
-}
-
 void Screen::saveCursor()
 {
     savedState.cursorColumn = cuX;
@@ -658,10 +653,8 @@ void Screen::newLine()
     index();
 }
 
-void Screen::checkSelection(int from, int to)
+void Screen::clearOverlappingSelection(int from, int to)
 {
-    if (selBegin == -1)
-        return;
     int scr_TL = loc(0, history->getLines());
     //Clear entire selection if it overlaps region [from, to]
     if ( (selBottomRight >= (from+scr_TL)) && (selTopLeft <= (to+scr_TL)) )
@@ -816,6 +809,10 @@ notcombine:
     int size = screenLines[cuY].size();
     if (size < cuX+w)
     {
+        // A line fills up one character at a time; allocate it once. The
+        // history keeps its own copy of what the line holds.
+        if (screenLines[cuY].capacity() < columns)
+            screenLines[cuY].reserve(columns);
         screenLines[cuY].resize(cuX+w);
     }
 
@@ -1031,20 +1028,32 @@ void Screen::moveImage(int dest, int sourceBegin, int sourceEnd)
     //so it matters that we do the copy in the right order -
     //forwards if dest < sourceBegin or backwards otherwise.
     //(search the web for 'memmove implementation' for details)
+    const int destLine = dest / columns;
+    const int sourceLine = sourceBegin / columns;
+    const int shift = qAbs(destLine - sourceLine);
+    LineProperty* properties = lineProperties.data();
+    //a source line a later step overwrites is moved, which spares sharing a buffer
+    //per line per scroll; a line nothing overwrites keeps its contents
     if (dest < sourceBegin)
     {
         for (int i=0;i<=lines;i++)
         {
-            screenLines[ (dest/columns)+i ] = screenLines[ (sourceBegin/columns)+i ];
-            lineProperties[(dest/columns)+i]=lineProperties[(sourceBegin/columns)+i];
+            if (i <= lines - shift)
+                screenLines[destLine + i] = std::move(screenLines[sourceLine + i]);
+            else
+                screenLines[destLine + i] = screenLines[sourceLine + i];
+            properties[destLine + i] = properties[sourceLine + i];
         }
     }
     else
     {
         for (int i=lines;i>=0;i--)
         {
-            screenLines[ (dest/columns)+i ] = screenLines[ (sourceBegin/columns)+i ];
-            lineProperties[(dest/columns)+i]=lineProperties[(sourceBegin/columns)+i];
+            if (shift > 0 && i >= shift)
+                screenLines[destLine + i] = std::move(screenLines[sourceLine + i]);
+            else
+                screenLines[destLine + i] = screenLines[sourceLine + i];
+            properties[destLine + i] = properties[sourceLine + i];
         }
     }
 

qmltermwidget/lib/Screen.h

@@ -242,7 +242,10 @@ public:
     /** Restores the state of a screen @p mode saved by calling saveMode() */
     void restoreMode(int mode);
     /** Returns whether the specified screen @p mode is enabled or not .*/
-    bool getMode(int mode) const;
+    bool getMode(int mode) const
+    {
+        return currentModes[mode];
+    }
 
     /**
      * Saves the current position and appearance (text color and style) of the cursor.
@@ -500,7 +503,12 @@ public:
      * @param from The start of the area to check.
      * @param to The end of the area to check
      */
-    void checkSelection(int from, int to);
+    void checkSelection(int from, int to)
+    {
+        // Every printed character checks; there is rarely a selection.
+        if (selBegin != -1)
+            clearOverlappingSelection(from, to);
+    }
 
     /**
      * Sets or clears an attribute of the current line.
@@ -633,6 +641,7 @@ private:
     void reverseRendition(Character& p) const;
 
     bool isSelectionValid() const;
+    void clearOverlappingSelection(int from, int to);
     // copies text from 'startIndex' to 'endIndex' to a stream
     // startIndex and endIndex are positions generated using the loc(x,y) macro
     void writeToStream(TerminalCharacterDecoder* decoder, int startIndex,

qmltermwidget/lib/Vt102Emulation.cpp

@@ -287,6 +287,14 @@ void Vt102Emulation::receiveChar(wchar_t cc)
   if (cc == DEL)
     return; //VT100: ignore.
 
+  // Most output is printable text between sequences: what lun() below does, with
+  // the tokenizer already reset whenever its buffer is empty.
+  if (tokenBufferPos == 0 && cc >= 32 && cc != ESC+128 && getMode(MODE_Ansi))
+  {
+    _currentScreen->displayCharacter(applyCharset(cc));
+    return;
+  }
+
   if (ces(CTL))
   {
     // ignore control characters in the text part of Xpe (aka OSC) "ESC]"
@@ -1705,11 +1713,6 @@ void Vt102Emulation::restoreMode(int m)
       resetMode(m);
 }
 
-bool Vt102Emulation::getMode(int m)
-{
-  return _currentModes.mode[m];
-}
-
 char Vt102Emulation::eraseChar() const
 {
   KeyboardTranslator::Entry entry = _keyTranslator->findEntry(

qmltermwidget/lib/Vt102Emulation.h

@@ -127,7 +127,7 @@ private:
   void setDefaultMargins();
 
   // returns true if 'mode' is set or false otherwise
-  bool getMode    (int mode);
+  bool getMode    (int mode) { return _currentModes.mode[mode]; }
   // saves the current boolean value of 'mode'
   void saveMode   (int mode);
   // restores the boolean value of 'mode'

qmltermwidget/lib/konsole_wcwidth.cpp

@@ -19,6 +19,10 @@
 
 int konsole_wcwidth(wchar_t ucs)
 {
+    // Printable ASCII is one column in every locale, and most output is ASCII.
+    if (ucs >= 0x20 && ucs < 0x7f)
+        return 1;
+
 #ifdef HAVE_UTF8PROC
     utf8proc_category_t cat = utf8proc_category( ucs );
     if (cat == UTF8PROC_CATEGORY_CO) {