diff --git a/modules/input/evdev/BitUtils.cpp b/modules/input/evdev/BitUtils.cpp
new file mode 100644
index 0000000..3434c31
--- /dev/null
+++ b/modules/input/evdev/BitUtils.cpp
@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "BitUtils"
+//#define LOG_NDEBUG 0
+
+#include "BitUtils.h"
+
+#include <utils/Log.h>
+
+// Enables debug output for hasKeyInRange
+#define DEBUG_KEY_RANGE 0
+
+namespace android {
+
+#if DEBUG_KEY_RANGE
+static const char* bitstrings[16] = {
+    "0000", "0001", "0010", "0011",
+    "0100", "0101", "0110", "0111",
+    "1000", "1001", "1010", "1011",
+    "1100", "1101", "1110", "1111",
+};
+#endif
+
+bool testBitInRange(const uint8_t arr[], size_t start, size_t end) {
+#if DEBUG_KEY_RANGE
+    ALOGD("testBitInRange(%d, %d)", start, end);
+#endif
+    // Invalid range! This is nonsense; just say no.
+    if (end <= start) return false;
+
+    // Find byte array indices. The end is not included in the range, nor is
+    // endIndex. Round up for endIndex.
+    size_t startIndex = start / 8;
+    size_t endIndex = (end + 7) / 8;
+#if DEBUG_KEY_RANGE
+    ALOGD("startIndex=%d, endIndex=%d", startIndex, endIndex);
+#endif
+    for (size_t i = startIndex; i < endIndex; ++i) {
+        uint8_t bits = arr[i];
+        uint8_t mask = 0xff;
+#if DEBUG_KEY_RANGE
+        ALOGD("block %04d: %s%s", i, bitstrings[bits >> 4], bitstrings[bits & 0x0f]);
+#endif
+        if (bits) {
+            // Mask off bits before our start bit
+            if (i == startIndex) {
+                mask &= 0xff << (start % 8);
+            }
+            // Mask off bits after our end bit
+            if (i == endIndex - 1 && (end % 8)) {
+                mask &= 0xff >> (8 - (end % 8));
+            }
+#if DEBUG_KEY_RANGE
+            ALOGD("mask: %s%s", bitstrings[mask >> 4], bitstrings[mask & 0x0f]);
+#endif
+            // Test the index against the mask
+            if (bits & mask) return true;
+        }
+    }
+    return false;
+}
+}  // namespace android