libcxx initial import

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@103490 91177308-0d34-0410-b5e6-96231b3b80d8

src/random.cpp

@@ -0,0 +1,46 @@
+//===-------------------------- random.cpp --------------------------------===//
+//
+// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "random"
+#include "system_error"
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+random_device::random_device(const string& __token)
+    : __f_(open(__token.c_str(), O_RDONLY))
+{
+    if (__f_ <= 0)
+        __throw_system_error(errno, ("random_device failed to open " + __token).c_str());
+}
+
+random_device::~random_device()
+{
+    close(__f_);
+}
+
+unsigned
+random_device::operator()()
+{
+    unsigned r;
+    read(__f_, &r, sizeof(r));
+    return r;
+}
+
+double
+random_device::entropy() const
+{
+    return 0;
+}
+
+_LIBCPP_END_NAMESPACE_STD