From 9320c234ca84e3ea913727eb85b1d1ec7d33c01f Mon Sep 17 00:00:00 2001
From: root <root>
Date: Thu, 30 Oct 2014 21:59:18 +0000
Subject: *** empty log message ***

---
 src/emman.c | 148 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 148 insertions(+)
 create mode 100644 src/emman.c

diff --git a/src/emman.c b/src/emman.c
new file mode 100644
index 0000000..0b511f9
--- /dev/null
+++ b/src/emman.c
@@ -0,0 +1,148 @@
+/* enable mremap on GNU/Linux */
+#ifdef __linux__
+# define _GNU_SOURCE
+#endif
+
+/* enable the POSIX prototypes of mmap/munmap on Solaris */
+#ifdef __sun
+# if __STDC_VERSION__ >= 199901L
+#  define _XOPEN_SOURCE 600
+# else
+#  define _XOPEN_SOURCE 500
+# endif
+#endif
+
+#include "emman.h"
+
+#include <ecb.h>
+
+#include <string.h>
+
+#ifndef _WIN32
+# include <unistd.h>
+#endif
+
+#if _POSIX_MAPPED_FILES > 0
+# define USE_MMAP 1
+# include <sys/mman.h>
+# ifndef MAP_FAILED
+#  define MAP_FAILED ((void *)-1)
+# endif
+# ifndef MAP_ANONYMOUS
+#  ifdef MAP_ANON
+#   define MAP_ANONYMOUS MAP_ANON
+#  else
+#   undef USE_MMAP
+#  endif
+# endif
+# include <limits.h>
+# ifndef PAGESIZE
+static uint32_t pagesize;
+#  define BOOT_PAGESIZE if (!pagesize) pagesize = sysconf (_SC_PAGESIZE)
+#  define PAGESIZE pagesize
+# else
+#  define BOOT_PAGESIZE
+# endif
+#else
+# define PAGESIZE 1
+# define BOOT_PAGESIZE
+#endif
+
+size_t
+chunk_round (size_t size)
+{
+  BOOT_PAGESIZE;
+
+  return (size + (PAGESIZE - 1)) & ~(size_t)(PAGESIZE - 1);
+}
+
+size_t
+chunk_fit (size_t header, size_t element_size, size_t max_increase)
+{
+  uint32_t fill, maximum_fill = 0;
+  size_t minimum_size;
+
+  max_increase += header + element_size;
+
+  BOOT_PAGESIZE;
+
+  do
+    {
+      header += element_size;
+
+      fill = (uint32_t)header & (PAGESIZE - 1);
+
+      if (fill >= maximum_fill)
+        {
+          maximum_fill = fill + 16; /* size increase results in at least 16 bytes improvement */
+          minimum_size = header;
+        }
+    }
+  while (header < max_increase);
+
+  return minimum_size;
+}
+
+void *
+chunk_alloc (size_t size, int populate)
+{
+  #if USE_MMAP
+    void *ptr = MAP_FAILED;
+    
+    #ifdef MAP_POPULATE
+      if (populate & 1)
+        ptr = mmap (0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE, -1, 0);
+    #endif
+
+    if (ptr == MAP_FAILED)
+      ptr = mmap (0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+
+    if (ptr == MAP_FAILED)
+      return 0;
+
+    return ptr;
+  #else
+    return malloc (size);
+  #endif
+}
+
+void *
+chunk_realloc (void *ptr, size_t old_size, size_t new_size)
+{
+  #if USE_MMAP
+    #ifdef MREMAP_MAYMOVE /* requires _GNU_SOURCE */
+      void *ptr2 = mremap (ptr, old_size, new_size, MREMAP_MAYMOVE);
+
+      if (ptr2 == MAP_FAILED)
+        return 0;
+
+      return ptr2;
+    #else
+      void *ptr2 = chunk_alloc (new_size, 0);
+
+      if (!ptr2)
+        return ptr2;
+
+      /* TODO: prepopulate old_size pages instead of faulting them in */
+
+      memcpy (ptr2, ptr, old_size);
+      munmap (ptr, old_size);
+      return ptr2;
+    #endif
+  #else
+    return realloc (ptr, new_size);
+  #endif
+}
+
+void
+chunk_free (void *ptr, size_t size)
+{
+  #if USE_MMAP
+    /* we assume the OS never mmaps at address 0 */
+    if (ptr)
+      munmap (ptr, size);
+  #else
+    return free (ptr);
+  #endif
+}
+
-- 
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