1 files changed, 86 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/string/memcmp.cpp b/src/VBox/Runtime/common/string/memcmp.cpp
new file mode 100644
index 00000000..de7c3a27
--- /dev/null
+++ b/src/VBox/Runtime/common/string/memcmp.cpp
@@ -0,0 +1,86 @@
+/* $Id: memcmp.cpp $ */
+/** @file
+ * IPRT - CRT Strings, memcmp().
+ */
+
+/*
+ * Copyright (C) 2006-2020 Oracle Corporation
+ *
+ * This file is part of VirtualBox Open Source Edition (OSE), as
+ * available from http://www.virtualbox.org. This file is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GPL) as published by the Free Software
+ * Foundation, in version 2 as it comes in the "COPYING" file of the
+ * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+ * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
+ * VirtualBox OSE distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/string.h>
+#include <iprt/types.h>
+
+
+/**
+ * Copies a memory.
+ *
+ * @returns 0 if pvDst and pvSrc are equal
+ * @returns <0 if pvDst is 'smaller' than pvSrc.
+ * @returns >0 if pvDst is 'larger' than pvSrc.
+ *
+ * @param   pvDst       Pointer to the target block.
+ * @param   pvSrc       Pointer to the source block.
+ * @param   cb          The size of the block.
+ */
+#ifdef _MSC_VER
+# if _MSC_VER >= 1400
+__checkReturn int __cdecl memcmp(__in_bcount_opt(_Size) const void * pvDst, __in_bcount_opt(_Size) const void * pvSrc, __in size_t cb)
+# else
+int __cdecl memcmp(const void *pvDst, const void *pvSrc, size_t cb)
+# endif
+#else
+int memcmp(const void *pvDst, const void *pvSrc, size_t cb)
+#endif
+{
+    register union
+    {
+        uint8_t const  *pu8;
+        uint32_t const *pu32;
+        void const     *pv;
+    } uDst, uSrc;
+    uDst.pv = pvDst;
+    uSrc.pv = pvSrc;
+
+    /* 32-bit word compare. */
+    register size_t c = cb >> 2;
+    while (c-- > 0)
+    {
+        /* ASSUMES int is at least 32-bit! */
+        register int32_t iDiff = *uDst.pu32++ - *uSrc.pu32++;
+        if (iDiff)
+            return iDiff;
+    }
+
+    /* Remaining byte moves. */
+    c = cb & 3;
+    while (c-- > 0)
+    {
+        register int8_t iDiff = *uDst.pu8++ - *uSrc.pu8++;
+        if (iDiff)
+            return iDiff;
+    }
+
+    return 0;
+}
+