Terminal strip: natural sort for automatic ordering and terminal lists

"Position automatique" sorted labels as plain strings, so XAUZ1:10
came before XAUZ1:2. Add QETUtils::naturalLessThan (digit runs compared
by value, case insensitive; QCollator numeric mode is ignored by some
Qt backends) and use it in SortTerminalStripCommand, FreeTerminalModel
and the terminal strip tree dock.

sources/TerminalStrip/UndoCommand/sortterminalstripcommand.cpp

@@ -19,6 +19,7 @@
 #include "../terminalstrip.h"
 #include "../physicalterminal.h"
 #include "../realterminal.h"
+#include "../../utils/qetutils.h"
 
 SortTerminalStripCommand::SortTerminalStripCommand(TerminalStrip *strip, QUndoCommand *parent) :
 	QUndoCommand(parent),
@@ -46,46 +47,16 @@ void SortTerminalStripCommand::redo()
 
 void SortTerminalStripCommand::sort()
 {
-	std::sort(m_new_order.begin(), m_new_order.end(), [](QSharedPointer<PhysicalTerminal> arg1, QSharedPointer<PhysicalTerminal> arg2)
+	auto label_of = [](const QSharedPointer<PhysicalTerminal> &t) -> QString
 	{
-		const QRegularExpression rx(QStringLiteral("^\\d+"));
+		return t->realTerminalCount() ? t->realTerminals().constLast()->label()
+										: QString();
+	};
 
-		QString str1;
-		QString str2;
-		int int1 =-1;
-		int int2 =-1;
-
-		if (arg1->realTerminalCount())
-		{
-			str1 = arg1->realTerminals().constLast()->label();
-
-			auto match = rx.match(str1);
-			if (match.hasMatch()) {
-				int1 = match.captured(0).toInt();
-			}
-		}
-
-		if (arg2->realTerminalCount())
-		{
-			str2 = arg2->realTerminals().constLast()->label();
-
-			auto match = rx.match(str2);
-			if (match.hasMatch()) {
-				int2 = match.captured(0).toInt();
-			}
-		}
-
-			//Sort as numbers if both string
-			//start at least by a digit and
-			//the number of each string are different.
-			//Else sort as string
-		if (int1 >= 0 &&
-			int2 >= 0 &&
-			int1 != int2) {
-			return int1<int2;
-		}
-		else {
-			return str1<str2;
-		}
+	std::stable_sort(m_new_order.begin(), m_new_order.end(),
+			[&label_of](const QSharedPointer<PhysicalTerminal> &arg1,
+						const QSharedPointer<PhysicalTerminal> &arg2)
+	{
+		return QETUtils::naturalLessThan(label_of(arg1), label_of(arg2));
 	});
 }

sources/TerminalStrip/ui/freeterminalmodel.cpp

@@ -400,7 +400,7 @@ void FreeTerminalModel::fillTerminalVector()
         std::sort(free_terminal_vector.begin(), free_terminal_vector.end(),
                   [](TerminalElement *a, TerminalElement *b)
                   {
-                      return QETUtils::sortBeginIntString(a->elementData().m_informations.value(QETInformation::ELMT_LABEL).toString(),
+                      return QETUtils::naturalLessThan(a->elementData().m_informations.value(QETInformation::ELMT_LABEL).toString(),
                                                           b->elementData().m_informations.value(QETInformation::ELMT_LABEL).toString());
                   });
 

sources/TerminalStrip/ui/terminalstriptreedockwidget.cpp

@@ -27,6 +27,7 @@
 #include "../../qetgraphicsitem/terminalelement.h"
 #include "../terminalstrip.h"
 #include "../../qetinformation.h"
+#include "../../utils/qetutils.h"
 #include "freeterminalmodel.h"
 
 #include <QApplication>
@@ -257,7 +258,7 @@ void TerminalStripTreeDockWidget::buildTree()
 
 	auto ts_vector = m_project->terminalStrip();
 	std::sort(ts_vector.begin(), ts_vector.end(), [](TerminalStrip *a, TerminalStrip *b) {
-		return a->name() < b->name();
+		return QETUtils::naturalLessThan(a->name(), b->name());
 	});
 
 	for (const auto &ts : std::as_const(ts_vector)) {
@@ -355,9 +356,9 @@ void TerminalStripTreeDockWidget::addFreeTerminal()
 		//Sort the terminal element by label
 	std::sort(vector_.begin(), vector_.end(), [](TerminalElement *a, TerminalElement *b)
 	{
-		return a->elementData().m_informations.value(QETInformation::ELMT_LABEL).toString()
-				<
-				b->elementData().m_informations.value(QETInformation::ELMT_LABEL).toString();
+		return QETUtils::naturalLessThan(
+					a->elementData().m_informations.value(QETInformation::ELMT_LABEL).toString(),
+					b->elementData().m_informations.value(QETInformation::ELMT_LABEL).toString());
 	});
 
 	auto free_terminal_item = ui->m_tree_view->topLevelItem(1);

sources/utils/qetutils.cpp

@@ -133,6 +133,77 @@ bool QETUtils::sortBeginIntString(const QString &str_a, const QString &str_b)
 	}
 }
 
+/**
+ * @brief QETUtils::naturalLessThan
+ * Natural order comparison, case insensitive :
+ * "2" < "10" and "XAUZ1:2" < "XAUZ1:10".
+ * Runs of digits are compared by value wherever they are in the string.
+ * Implemented by hand because QCollator numeric mode is not honored by
+ * every Qt backend (it is ignored without ICU).
+ * The result is a strict weak ordering, so it is safe to use with std::sort.
+ * @param str_a
+ * @param str_b
+ * @return true if str_a must be placed before str_b
+ */
+bool QETUtils::naturalLessThan(const QString &str_a, const QString &str_b)
+{
+	const int len_a = str_a.size();
+	const int len_b = str_b.size();
+	int i = 0;
+	int j = 0;
+	int zeros_diff = 0; //Tie breaker : "01" and "1" have the same value
+
+	while (i < len_a && j < len_b)
+	{
+		const QChar ca = str_a.at(i);
+		const QChar cb = str_b.at(j);
+
+		if (ca.isDigit() && cb.isDigit())
+		{
+			int start_a = i;
+			int start_b = j;
+			while (i < len_a && str_a.at(i).isDigit()) { ++i; }
+			while (j < len_b && str_b.at(j).isDigit()) { ++j; }
+
+			int sig_a = start_a;
+			int sig_b = start_b;
+			while (sig_a < i - 1 && str_a.at(sig_a) == QLatin1Char('0')) { ++sig_a; }
+			while (sig_b < j - 1 && str_b.at(sig_b) == QLatin1Char('0')) { ++sig_b; }
+
+			const int digits_a = i - sig_a;
+			const int digits_b = j - sig_b;
+			if (digits_a != digits_b) {
+				return digits_a < digits_b;
+			}
+
+			const int cmp = QStringView(str_a).mid(sig_a, digits_a)
+					.compare(QStringView(str_b).mid(sig_b, digits_b));
+			if (cmp != 0) {
+				return cmp < 0;
+			}
+
+			if (zeros_diff == 0) {
+				zeros_diff = (sig_a - start_a) - (sig_b - start_b);
+			}
+		}
+		else
+		{
+			const QChar la = ca.toCaseFolded();
+			const QChar lb = cb.toCaseFolded();
+			if (la != lb) {
+				return la < lb;
+			}
+			++i;
+			++j;
+		}
+	}
+
+	if (i < len_a || j < len_b) {
+		return (len_a - i) < (len_b - j); //The shortest remaining part first
+	}
+	return zeros_diff > 0 ? false : zeros_diff < 0; //"1" before "01"
+}
+
 /**
  * @brief QETUtils::pixelSizedFont
  * Set the font size to pixelSize instead of pointSize (if needed).

sources/utils/qetutils.h

@@ -59,6 +59,7 @@ namespace QETUtils
 	};
 
 	bool sortBeginIntString(const QString &str_a, const QString &str_b);
+	bool naturalLessThan(const QString &str_a, const QString &str_b);
 
 	template <typename T>
 	QVector<QWeakPointer<T>> sharedVectorToWeak(const QVector<QSharedPointer<T>> &vector)