1 files changed, 79 insertions, 0 deletions
diff --git a/numericrange.h b/numericrange.h
new file mode 100644
index 0000000..d86e578
--- /dev/null
+++ b/numericrange.h
@@ -0,0 +1,79 @@
+#ifndef NUMERICRANGE_H
+#define NUMERICRANGE_H
+
+#include <iterator>
+#include <stdexcept>
+
+/*
+ * A range in [first, last) in steps of 1.
+ */
+template<typename T>
+class NumericRange
+{
+public:
+    class iterator
+    {
+        friend class NumericRange;
+    public:
+        typedef iterator self_type;
+	typedef T value_type;
+	typedef T& reference;
+	typedef T* pointer;
+	typedef std::bidirectional_iterator_tag iterator_category;
+	typedef int difference_type;
+
+        iterator(const T &first): m_value(first) {}
+
+        T operator *() const { return m_value; }
+        const iterator &operator ++() {
+            ++m_value;
+            return *this;
+        }
+        iterator operator++(int) {
+            iterator copy(*this);
+            ++m_value;
+            return copy;
+        }
+        const iterator &operator --() {
+            --m_value;
+            return *this;
+        }
+        iterator operator--(int) {
+            iterator copy(*this);
+            --m_value;
+            return copy;
+        }
+
+        bool operator ==(const iterator &other) const {
+            return m_value == other.m_value;
+        }
+        bool operator !=(const iterator &other) const {
+            return m_value != other.m_value;
+        }
+
+    private:
+        T m_value;
+    };
+
+    NumericRange(const T &first, const T &last)
+        : m_begin(first)
+        , m_end(last)
+    {
+        if (first > last) {
+            throw std::logic_error("first > last");
+        }
+    }
+
+    typedef const iterator const_iterator;
+
+    iterator begin() const { return m_begin; }
+    iterator end() const   { return m_end; }
+
+    const_iterator cbegin() const { return m_begin; }
+    const_iterator cend() const   { return m_end; }
+
+private:
+    iterator m_begin, m_end;
+};
+
+#endif // NUMERICRANGE_H