diff --git a/CMakeLists.txt b/CMakeLists.txt
index 19e208c..6cae0cd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -7,12 +7,15 @@ project(mimir)
 
 set(PUBLIC_HEADERS
   include/mimir.h
+  include/arena.h
   include/block.h
   include/util.h
 )
 
 set(SRCS
+  src/arena.cpp
   src/block.cpp
+  src/mimir.cpp
   src/util.cpp
 )
 
diff --git a/include/block.h b/include/block.h
index 9ab4bc4..0865b6e 100644
--- a/include/block.h
+++ b/include/block.h
@@ -39,7 +39,6 @@
 #endif
 
 namespace mimir {
-void init();
 class Block
 {
 public:
@@ -127,6 +126,7 @@ private:
   // Assert if not locked
   void assertLocked();
 
-};
+}; // class Block
+
 } // namespace mimir
 
diff --git a/include/mimir.h b/include/mimir.h
index c92330b..c924040 100644
--- a/include/mimir.h
+++ b/include/mimir.h
@@ -32,4 +32,9 @@
 #pragma once
 
 #include "block.h"
+#include "arena.h"
 #include "util.h"
+
+namespace mimir {
+void init();
+}
\ No newline at end of file
diff --git a/include/util.h b/include/util.h
index 44fd513..6cae46e 100644
--- a/include/util.h
+++ b/include/util.h
@@ -40,5 +40,5 @@ std::string GetFileExtension(const std::string& name);
 std::string GetFileBase(const std::string& name);
 std::string GetFilePath(const std::string& name);
 
-} // namespace mimir
 } // namespace util
+} // namespace mimir
diff --git a/src/block.cpp b/src/block.cpp
index f9a9ea0..b64128d 100644
--- a/src/block.cpp
+++ b/src/block.cpp
@@ -30,6 +30,7 @@
 //
 
 #include "../include/mimir.h"
+#include "mimir_impl.h"
 
 #if defined(__unix__) || defined(__APPLE__) || defined(ANDROID)
 #include <unistd.h>
@@ -43,8 +44,6 @@
 #include <cstring>
 
 #define KRENGINE_MIN_MMAP 32768
-#define KRAKEN_MEM_ROUND_DOWN_PAGE(x) ((x) & ~(KRENGINE_SYS_ALLOCATION_GRANULARITY - 1))
-#define KRAKEN_MEM_ROUND_UP_PAGE(x) ((((x) - 1) & ~(KRENGINE_SYS_ALLOCATION_GRANULARITY - 1)) + KRENGINE_SYS_ALLOCATION_GRANULARITY)
 
 namespace mimir {
 
@@ -52,28 +51,6 @@ int m_mapCount = 0;
 size_t m_mapSize = 0;
 size_t m_mapOverhead = 0;
 
-int KRENGINE_SYS_ALLOCATION_GRANULARITY;
-int KRENGINE_SYS_PAGE_SIZE;
-
-void init()
-{
-#if defined(_WIN32) || defined(_WIN64)
-
-  SYSTEM_INFO winSysInfo;
-  GetSystemInfo(&winSysInfo);
-  KRENGINE_SYS_ALLOCATION_GRANULARITY = winSysInfo.dwAllocationGranularity;
-  KRENGINE_SYS_PAGE_SIZE = winSysInfo.dwPageSize;
-
-#elif defined(__APPLE__) || __linux__ || defined(ANDROID)
-
-  KRENGINE_SYS_PAGE_SIZE = getpagesize();
-  KRENGINE_SYS_ALLOCATION_GRANULARITY = KRENGINE_SYS_PAGE_SIZE;
-
-#else
-#error Unsupported
-#endif
-}
-
 Block::Block()
 {
   m_data = NULL;
@@ -467,36 +444,6 @@ std::string Block::getString()
   return ret;
 }
 
-#if defined(_WIN32) || defined(_WIN64)
-void ReportWindowsLastError(LPCTSTR lpszFunction)
-{
-  LPVOID lpMsgBuf;
-  LPVOID lpDisplayBuf;
-  DWORD dw = GetLastError();
-
-  FormatMessage(
-    FORMAT_MESSAGE_ALLOCATE_BUFFER |
-    FORMAT_MESSAGE_FROM_SYSTEM |
-    FORMAT_MESSAGE_IGNORE_INSERTS,
-    NULL,
-    dw,
-    MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
-    (LPTSTR)&lpMsgBuf,
-    0, NULL);
-
-  // Display the error message and exit the process
-
-  lpDisplayBuf = (LPVOID)LocalAlloc(LMEM_ZEROINIT,
-  (lstrlen((LPCTSTR)lpMsgBuf) + lstrlen((LPCTSTR)lpszFunction) + 40) * sizeof(TCHAR));
-  fprintf(stderr,
-    TEXT("%s failed with error %d: %s\n"),
-    lpszFunction, dw, (LPCTSTR)lpMsgBuf);
-
-  LocalFree(lpMsgBuf);
-  LocalFree(lpDisplayBuf);
-}
-#endif
-
 // Lock the memory, forcing it to be loaded into a contiguous block of address space
 void Block::lock()
 {