1 files changed, 51 insertions, 0 deletions
diff --git a/libc/string/memcmp.c b/libc/string/memcmp.c
new file mode 100644
index 0000000..8640954
--- /dev/null
+++ b/libc/string/memcmp.c
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+#include <string.h>
+
+int memcmp(const void *s1, const void *s2, size_t n)
+{
+    const unsigned char*  p1   = s1;
+    const unsigned char*  end1 = p1 + n;
+    const unsigned char*  p2   = s2;
+    int                   d = 0;
+
+    for (;;) {
+        if (d || p1 >= end1) break;
+        d = (int)*p1++ - (int)*p2++;
+
+        if (d || p1 >= end1) break;
+        d = (int)*p1++ - (int)*p2++;
+
+        if (d || p1 >= end1) break;
+        d = (int)*p1++ - (int)*p2++;
+
+        if (d || p1 >= end1) break;
+        d = (int)*p1++ - (int)*p2++;
+    }
+    return d;
+}