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+/*****************************************************************************
+
+Copyright (c) 2023, 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
+/* A normally small vector, inspired by llvm::SmallVector */
+#include "my_global.h"
+#include <iterator>
+#include <memory>
+
+class small_vector_base
+{
+protected:
+ typedef uint32_t Size_T;
+ void *BeginX;
+ Size_T Size= 0, Capacity;
+ small_vector_base()= delete;
+ small_vector_base(void *small, size_t small_size)
+ : BeginX(small), Capacity(Size_T(small_size)) {}
+ ATTRIBUTE_COLD void grow_by_1(void *small, size_t element_size);
+public:
+ size_t size() const { return Size; }
+ size_t capacity() const { return Capacity; }
+ bool empty() const { return !Size; }
+ void clear() { Size= 0; }
+protected:
+ void set_size(size_t N) { Size= Size_T(N); }
+};
+
+template <typename T, unsigned N>
+class small_vector : public small_vector_base
+{
+ /** The fixed storage allocation */
+ T small[N];
+
+ using small_vector_base::set_size;
+
+ void grow_if_needed()
+ {
+ if (unlikely(size() >= capacity()))
+ grow_by_1(small, sizeof *small);
+ }
+
+public:
+ small_vector() : small_vector_base(small, N)
+ {
+ TRASH_ALLOC(small, sizeof small);
+ }
+ ~small_vector()
+ {
+ if (small != begin())
+ my_free(begin());
+ MEM_MAKE_ADDRESSABLE(small, sizeof small);
+ }
+
+ using iterator= T *;
+ using const_iterator= const T *;
+ using reverse_iterator= std::reverse_iterator<iterator>;
+ using reference= T &;
+ using const_reference= const T&;
+
+ iterator begin() { return static_cast<iterator>(BeginX); }
+ const_iterator begin() const { return static_cast<const_iterator>(BeginX); }
+ iterator end() { return begin() + size(); }
+ const_iterator end() const { return begin() + size(); }
+
+ reverse_iterator rbegin() { return reverse_iterator(end()); }
+ reverse_iterator rend() { return reverse_iterator(begin()); }
+
+ reference operator[](size_t i) { assert(i < size()); return begin()[i]; }
+ const_reference operator[](size_t i) const
+ { return const_cast<small_vector&>(*this)[i]; }
+
+ void erase(const_iterator S, const_iterator E)
+ {
+ set_size(std::move(const_cast<iterator>(E), end(),
+ const_cast<iterator>(S)) - begin());
+ }
+
+ void emplace_back(T &&arg)
+ {
+ grow_if_needed();
+ ::new (end()) T(arg);
+ set_size(size() + 1);
+ }
+};