From 7e8b5c0b64165144b2c960f340ed283ed71f8d9f Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Sun, 17 Jul 2016 21:55:29 -0400
Subject: [PATCH] Allow PagedBuffer to hold non-power-of-2-sized objects

---
 src/core/PagedBuffer.h | 23 ++++++++---------------
 1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/src/core/PagedBuffer.h b/src/core/PagedBuffer.h
index 0ba04b0..da2d1eb 100644
--- a/src/core/PagedBuffer.h
+++ b/src/core/PagedBuffer.h
@@ -4,6 +4,7 @@
 #include "System.h"
 #include <vector>
 #include <stdint.h>
+#include <stdlib.h>
 
 template <typename T>
 class PagedBuffer
@@ -11,14 +12,10 @@ class PagedBuffer
 public:
     /**
      * Create a PagedBuffer.
-     *
-     * Note: sizeof(T) must be a power of 2. A single page can hold
-     * System::page_size / sizeof(T) entries.
      */
     PagedBuffer<T>()
     {
-        static_assert((sizeof(T) & (sizeof(T) - 1)) == 0,
-                      "sizeof(T) must be a power of 2");
+        m_n_per_page = System::page_size / sizeof(T);
         m_size = 0u;
     }
 
@@ -32,7 +29,7 @@ public:
 
     const T & operator[](unsigned int index) const
     {
-        while (index >= (m_pages.size() * n_per_page()))
+        while (index >= (m_pages.size() * m_n_per_page))
         {
             grow();
         }
@@ -41,7 +38,7 @@ public:
 
     T & operator[](unsigned int index)
     {
-        while (index >= (m_pages.size() * n_per_page()))
+        while (index >= (m_pages.size() * m_n_per_page))
         {
             grow();
         }
@@ -51,29 +48,25 @@ public:
     size_t size() { return m_size; }
 
 protected:
-    unsigned int n_per_page()
-    {
-        return System::page_size / sizeof(T);
-    }
-
     unsigned int page_index(unsigned int index)
     {
-        return index / n_per_page();
+        return index / m_n_per_page;
     }
 
     unsigned int index_in_page(unsigned int index)
     {
-        return index % n_per_page();
+        return index % m_n_per_page;
     }
 
     void grow()
     {
         m_pages.push_back((T *)System::alloc_pages(1));
-        m_size += n_per_page();
+        m_size += m_n_per_page;
     }
 
     std::vector<T *> m_pages;
     unsigned long m_size;
+    unsigned int m_n_per_page;
 };
 
 #endif