1 files changed, 76 insertions, 0 deletions
diff --git a/libc/stdlib/malloc/realloc.c b/libc/stdlib/malloc/realloc.c
new file mode 100644
index 000000000..faf7ac2f8
--- /dev/null
+++ b/libc/stdlib/malloc/realloc.c
@@ -0,0 +1,76 @@
+/*
+ * libc/stdlib/malloc-zarg/realloc.c -- realloc function
+ *
+ *  Copyright (C) 2002  NEC Corporation
+ *  Copyright (C) 2002  Miles Bader <miles@gnu.org>
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License.  See the file COPYING.LIB in the main
+ * directory of this archive for more details.
+ * 
+ * Written by Miles Bader <miles@gnu.org>
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+
+#include "malloc.h"
+#include "heap.h"
+
+
+void *realloc (void *mem, size_t new_size)
+{
+  if (! mem)
+    return malloc (new_size);
+  else
+    {
+      void *base_mem = (size_t *)mem - 1;
+      size_t size = *(size_t *)base_mem;
+
+      MALLOC_DEBUG ("realloc: 0x%lx, %d (base = 0x%lx, total_size = %d)\n",
+		    (long)mem, new_size, (long)base_mem, size);
+
+      if (new_size <= size)
+	return mem;
+      else
+	{
+	  void *new_mem = 0;
+	  size_t ext_size = new_size - size;
+	  void *ext_addr = (char *)base_mem + ext_size;
+
+	  if (size >= MALLOC_MMAP_THRESHOLD)
+	    /* Try to extend this block in place using mmap.  */
+	    {
+	      ext_size += MALLOC_ROUND_UP_TO_PAGE_SIZE (ext_size);
+
+	      new_mem = mmap (ext_addr, ext_size, PROT_READ | PROT_WRITE,
+			      MAP_FIXED | MAP_SHARED | MAP_ANONYMOUS, 0, 0);
+	      if (new_mem == MAP_FAILED)
+		/* Can't do it.  */
+		ext_size = 0;
+	    }
+	  else
+	    ext_size = __heap_alloc_at (&__malloc_heap, ext_addr, ext_size);
+
+	  if (! ext_size)
+	    /* Our attempts to extend MEM in place failed, just
+	       allocate-and-copy.  */
+	    {
+	      new_mem = malloc (new_size);
+	      if (new_mem)
+		{
+		  memcpy (new_mem, mem, size);
+		  free (mem);
+		}
+	    }
+
+	  if (new_mem)
+	    MALLOC_DEBUG ("  realloc: returning 0x%lx"
+			  " (base:0x%lx, total_size:%d)\n",
+			  (long)new_mem, (long)new_mem - sizeof(size_t), size);
+
+	  return new_mem;
+	}
+    }
+}