From 4616450af1f6c39f33963e9835531f4d99077623 Mon Sep 17 00:00:00 2001
From: Roland Bock <rbock@eudoxos.de>
Date: Sun, 1 Oct 2023 15:10:15 +0200
Subject: [PATCH] Simplify logic for circular_buffer<T>::set_capacity

---
 include/sqlpp11/detail/circular_buffer.h | 40 ++++++------------------
 1 file changed, 10 insertions(+), 30 deletions(-)

diff --git a/include/sqlpp11/detail/circular_buffer.h b/include/sqlpp11/detail/circular_buffer.h
index df540e81..994f8c35 100644
--- a/include/sqlpp11/detail/circular_buffer.h
+++ b/include/sqlpp11/detail/circular_buffer.h
@@ -73,40 +73,20 @@ namespace sqlpp
     }
 
     template <typename T>
-    void circular_buffer<T>::set_capacity(std::size_t capacity)
+    void circular_buffer<T>::set_capacity(std::size_t new_capacity)
     {
-      if (capacity == _capacity)
+      if (new_capacity == _capacity)
       {
         return;
       }
-      if (_tail >= _head)
-      {
-        if (empty() == false)
-        {
-          std::rotate(_data.begin(), _data.begin() + _tail, _data.end());
-        }
-        _head = (capacity > _size) ? _size : 0;
-        _tail = 0;
-      }
-      else
-      {
-        if (capacity < _head)
-        {
-          std::rotate(_data.begin(), _data.begin() + _tail, _data.begin() + _head);
-          _head = (capacity > _size) ? _size : 0;
-          _tail = 0;
-        }
-        else if (capacity == _head)
-        {
-          _head = 0;
-        }
-      }
-      _data.resize(capacity);
-      _capacity = capacity;
-      if (_size > capacity)
-      {
-        _size = capacity;
-      }
+      // Reduce the number of cases by rotating `front()` to `_data.begin()`.
+      std::rotate(_data.begin(), _data.begin() + _tail, _data.end());
+
+      _tail = 0;
+      _head = (new_capacity > _size) ? _size : 0;
+      _data.resize(new_capacity);
+      _capacity = new_capacity;
+      _size = std::min(_size, new_capacity);
     }
 
     template <typename T>