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diff --git a/src/base/math_util.hh b/src/base/math_util.hh
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+++ b/src/base/math_util.hh
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+/**
+ * Copyright (c) 2020, Timothy Stack
+ *
+ * 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.
+ * * Neither the name of Timothy Stack nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
+ */
+
+#ifndef lnav_math_util_hh
+#define lnav_math_util_hh
+
+#include <sys/types.h>
+
+#undef rounddown
+
+/**
+ * Round down a number based on a given granularity.
+ *
+ * @param
+ * @param step The granularity.
+ */
+template<typename Size, typename Step>
+inline int
+rounddown(Size size, Step step)
+{
+    return size - (size % step);
+}
+
+inline int
+rounddown_offset(size_t size, int step, int offset)
+{
+    return size - ((size - offset) % step);
+}
+
+inline size_t
+roundup_size(size_t size, int step)
+{
+    size_t retval = size + step;
+
+    retval -= (retval % step);
+
+    return retval;
+}
+
+template<typename T>
+T
+abs_diff(T a, T b)
+{
+    return a > b ? a - b : b - a;
+}
+
+#endif