Improved support from removing rows in crud tabs.

It can handle now complex selections and reports back errors encountered
when removing the rows fails.

core/IntegerRange.h

@@ -0,0 +1,136 @@
+#ifndef INTEGERRANGE_H
+#define INTEGERRANGE_H
+
+#include <algorithm>
+
+template <typename Value>
+class IntegerRange {
+public:
+	using Val = Value;
+
+	IntegerRange() = default;
+	IntegerRange(Value start, Value length)
+		: m_start(start)
+		, m_length(length)
+	{}
+
+	bool canCombine(const IntegerRange &rhs) const
+	{
+		if (m_start == rhs.m_start) {
+			return true;
+		}
+		if (m_start < rhs.m_start) {
+			return m_start + m_length >= rhs.m_start;
+		}
+		else {
+			return rhs.canCombine(*this);
+		}
+	}
+
+	void setLength(Value length)
+	{
+		m_length = length;
+	}
+
+	Value length() const { return m_length; }
+
+	void setStart(Value start)
+	{
+		m_start = start;
+	}
+	Value start() const { return m_start; }
+
+	void setEnd(Value end)
+	{
+		m_length = end - m_start;
+	}
+	Value end() const { return m_start + m_length; }
+
+	bool operator==(const IntegerRange &rhs) const
+	{
+		return m_start == rhs.m_start && m_length == rhs.m_length;
+	}
+
+	bool operator!=(const IntegerRange &rhs) const
+	{
+		return !operator==(rhs);
+	}
+
+	bool operator<(const IntegerRange &rhs) const
+	{
+		return m_start < rhs.m_start;
+	}
+
+	bool operator<=(const IntegerRange &rhs) const
+	{
+		return m_start < rhs.m_start || (m_start == rhs.m_start && m_length < rhs.m_length);
+	}
+
+	bool operator>(const IntegerRange &rhs) const
+	{
+		return m_start > rhs.m_start;
+	}
+
+	bool operator>=(const IntegerRange &rhs) const
+	{
+		return m_start > rhs.m_start || (m_start == rhs.m_start && m_length > rhs.m_length);
+	}
+private:
+	Value m_start = 0;
+	Value m_length = 0;
+};
+
+/// This function merges elements that overlap or touch into single elements
+/// and stores the resulting elements into the destination range starting at d_first
+///
+/// Function assumes the input range is sorted
+template <typename InputIt, typename OutputIt>
+OutputIt merge_ranges(InputIt first, InputIt last, OutputIt d_first)
+{
+	using Elem = typename InputIt::value_type;
+
+	InputIt i = first;
+	while (first != last) {
+		Elem e = *first;
+		++first;
+		while (first != last && e.canCombine(*first)) {
+			if (first->end() > e.end())
+				e.setEnd(first->end());
+			++first;
+		}
+		d_first = e;
+	}
+	return d_first;
+}
+
+//template <typename Container, typename RangeType>
+//void insert(Container cont, RangeType range)
+//{
+//	auto ipos = std::lower_bound(begin(cont), end(cont), range);
+
+//	// Maybe it can be combined with previous
+//	if (ipos != begin(cont)) {
+//		auto prev = ipos;
+//		--prev;
+//		if (prev->canCombine(range))
+//			prev->setEnd(range->end());
+
+//	}
+//	else {
+//		// We need to either insert it or combine with the next
+//		if (ipos != end(cont) && range.canCombine(*ipos)) {
+//			// remember where end of ipos range was
+//			auto e = ipos->end();
+//			if (e > range.end())
+//				range.setEnd(e);
+//			// We cannot modify element in set so we remove one element and add a new one
+//			ipos = cont.erase(ipos);
+//			cont.insert(ipos, range);
+//		}
+//		else {
+//			cont->insert(ipos, range);
+//		}
+//	}
+//}
+
+#endif // INTEGERRANGE_H

core/core.pro

@@ -59,7 +59,8 @@ HEADERS += PasswordManager.h \
     SqlAstSelectListEntry.h \
     SqlAstSelect.h \
     SqlAstExpression.h \
-    std_utils.h
+    std_utils.h \
+    IntegerRange.h
 	
 unix {
     target.path = /usr/lib