add PagedBuffer; use own main() for tests

src/core/PagedBuffer.h

@@ -0,0 +1,79 @@
+#ifndef PAGEDBUFFER_H
+#define PAGEDBUFFER_H
+
+#include "System.h"
+#include <vector>
+#include <stdint.h>
+
+template <typename T>
+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_size = 0u;
+    }
+
+    ~PagedBuffer<T>()
+    {
+        for (auto it : m_pages)
+        {
+            System::free_pages(it, 1);
+        }
+    }
+
+    const T & operator[](unsigned int index) const
+    {
+        while (index >= (m_pages.size() * n_per_page()))
+        {
+            grow();
+        }
+        return m_pages[page_index(index)][index_in_page(index)];
+    }
+
+    T & operator[](unsigned int index)
+    {
+        while (index >= (m_pages.size() * n_per_page()))
+        {
+            grow();
+        }
+        return m_pages[page_index(index)][index_in_page(index)];
+    }
+
+    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();
+    }
+
+    unsigned int index_in_page(unsigned int index)
+    {
+        return index % n_per_page();
+    }
+
+    void grow()
+    {
+        m_pages.push_back((T *)System::alloc_pages(1));
+        m_size += n_per_page();
+    }
+
+    std::vector<T *> m_pages;
+    unsigned long m_size;
+};
+
+#endif