st_::span fixes

move span.h to a proper place to make it available for the whole server

Reformat it.

Constuctors from a contigous container are fixed
to use cont.data() instead of cont.begin()

span<>::index_type is replaced with span<>::size_type

include/span.h

+/*****************************************************************************
+
+Copyright (c) 2019, 2020 MariaDB Corporation.
+
+This program is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free Software
+Foundation; version 2 of the License.
+
+This program is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA
+
+*****************************************************************************/
+
+#pragma once
+
+#include <cstddef>
+#include <iterator>
+
+namespace st_
+{
+
+template <class ElementType> class span
+{
+public:
+  typedef ElementType element_type;
+  typedef ElementType value_type;
+  typedef size_t size_type;
+  typedef ptrdiff_t difference_type;
+  typedef element_type *pointer;
+  typedef const element_type *const_pointer;
+  typedef element_type &reference;
+  typedef const element_type &const_reference;
+  typedef pointer iterator;
+  typedef const_pointer const_iterator;
+  typedef std::reverse_iterator<iterator> reverse_iterator;
+  typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
+
+  span() : data_(NULL), size_(0) {}
+
+  span(pointer ptr, size_type count) : data_(ptr), size_(count) {}
+
+  span(pointer first, pointer last) : data_(first), size_(last - first) {}
+
+  template <size_t N> span(element_type (&arr)[N]) : data_(arr), size_(N) {}
+
+  template <class Container>
+  span(Container &cont) : data_(cont.data()), size_(cont.size())
+  {
+  }
+
+  template <class Container>
+  span(const Container &cont) : data_(cont.data()), size_(cont.size())
+  {
+  }
+
+  span(const span &other) : data_(other.data_), size_(other.size_) {}
+
+  ~span(){};
+
+  span &operator=(const span &other)
+  {
+    data_= other.data_;
+    size_= other.size_;
+    return *this;
+  }
+
+  template <size_t Count> span<element_type> first() const
+  {
+    assert(!empty());
+    return span(data_, 1);
+  }
+  template <size_t Count> span<element_type> last() const
+  {
+    assert(!empty());
+    return span(data_ + size() - 1, 1);
+  }
+
+  span<element_type> first(size_type count) const
+  {
+    assert(!empty());
+    return span(data_, 1);
+  }
+  span<element_type> last(size_type count) const
+  {
+    assert(!empty());
+    return span(data_ + size() - 1, 1);
+  }
+  span<element_type> subspan(size_type offset, size_type count) const
+  {
+    assert(!empty());
+    assert(size() >= offset + count);
+    return span(data_ + offset, count);
+  }
+
+  size_type size() const { return size_; }
+  size_type size_bytes() const { return size_ * sizeof(ElementType); }
+  bool empty() const __attribute__((warn_unused_result)) { return size_ == 0; }
+
+  reference operator[](size_type idx) const
+  {
+    assert(size() > idx);
+    return data_[idx];
+  }
+  reference front() const
+  {
+    assert(!empty());
+    return data_[0];
+  }
+  reference back() const
+  {
+    assert(!empty());
+    return data_[size() - 1];
+  }
+  pointer data() const
+  {
+    assert(!empty());
+    return data_;
+  }
+
+  iterator begin() const { return data_; }
+  iterator end() const { return data_ + size_; }
+  reverse_iterator rbegin() const
+  {
+    return std::reverse_iterator<iterator>(std::advance(end(), -1));
+  }
+  reverse_iterator rend() const
+  {
+    return std::reverse_iterator<iterator>(std::advance(begin(), -1));
+  }
+
+private:
+  pointer data_;
+  size_type size_;
+};
+
+} // namespace st_

storage/innobase/include/span.h

-/*****************************************************************************
-
-Copyright (c) 2019, 2020 MariaDB Corporation.
-
-This program is free software; you can redistribute it and/or modify it under
-the terms of the GNU General Public License as published by the Free Software
-Foundation; version 2 of the License.
-
-This program is distributed in the hope that it will be useful, but WITHOUT
-ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
-FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License along with
-this program; if not, write to the Free Software Foundation, Inc.,
-51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA
-
-*****************************************************************************/
-
-#pragma once
-
-#include <cstddef>
-#include <iterator>
-
-namespace st_ {
-
-template <class ElementType> class span {
-public:
-	typedef ElementType element_type;
-	typedef ElementType value_type;
-	typedef size_t index_type;
-	typedef ptrdiff_t difference_type;
-	typedef element_type* pointer;
-	typedef const element_type* const_pointer;
-	typedef element_type& reference;
-	typedef const element_type& const_reference;
-	typedef pointer iterator;
-	typedef const_pointer const_iterator;
-	typedef std::reverse_iterator<iterator> reverse_iterator;
-	typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
-
-	span() : data_(NULL), size_(0) {}
-
-	span(pointer ptr, index_type count) : data_(ptr), size_(count) {}
-
-	span(pointer first, pointer last) : data_(first), size_(last - first) {}
-
-	template <size_t N> span(element_type (&arr)[N]) : data_(arr), size_(N)
-	{
-	}
-
-	template <class Container>
-	span(Container& cont) : data_(cont.begin()), size_(cont.size())
-	{
-	}
-
-	template <class Container>
-	span(const Container& cont) : data_(cont.begin()), size_(cont.size())
-	{
-	}
-
-	span(const span& other) : data_(other.data_), size_(other.size_) {}
-
-	~span(){};
-
-	span& operator=(const span& other)
-	{
-		data_ = other.data_;
-		size_ = other.size_;
-		return *this;
-	}
-
-	template <size_t Count> span<element_type> first() const
-	{
-		assert(!empty());
-		return span(data_, 1);
-	}
-	template <size_t Count> span<element_type> last() const
-	{
-		assert(!empty());
-		return span(data_ + size() - 1, 1);
-	}
-
-	span<element_type> first(index_type count) const
-	{
-		assert(!empty());
-		return span(data_, 1);
-	}
-	span<element_type> last(index_type count) const
-	{
-		assert(!empty());
-		return span(data_ + size() - 1, 1);
-	}
-	span<element_type> subspan(index_type offset, index_type count) const
-	{
-		assert(!empty());
-		assert(size() >= offset + count);
-		return span(data_ + offset, count);
-	}
-
-	index_type size() const { return size_; }
-	index_type size_bytes() const { return size_ * sizeof(ElementType); }
-	bool empty() const __attribute__((warn_unused_result))
-	{
-		return size_ == 0;
-	}
-
-	reference operator[](index_type idx) const
-	{
-		assert(size() > idx);
-		return data_[idx];
-	}
-	reference front() const
-	{
-		assert(!empty());
-		return data_[0];
-	}
-	reference back() const
-	{
-		assert(!empty());
-		return data_[size() - 1];
-	}
-	pointer data() const
-	{
-		assert(!empty());
-		return data_;
-	}
-
-	iterator begin() const { return data_; }
-	iterator end() const { return data_ + size_; }
-	reverse_iterator rbegin() const
-	{
-		return std::reverse_iterator<iterator>(std::advance(end(), -1));
-	}
-	reverse_iterator rend() const
-	{
-		return std::reverse_iterator<iterator>(
-		    std::advance(begin(), -1));
-	}
-
-private:
-	pointer data_;
-	index_type size_;
-};
-
-} // namespace st_