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+/*
+ * Copyright (c) 2003 The Regents of The University of Michigan
+ * 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 the copyright holders 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 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.
+ */
+
+#ifndef __INTMATH_H__
+#define __INTMATH_H__
+
+// Returns the prime number one less than n.
+int PrevPrime(int n);
+
+// Determine if a number is prime
+inline bool
+IsPrime(int n)
+{
+  int i;
+
+  if (n == 2 || n == 3)
+    return true;
+
+  // Don't try every odd number to prove if it is a prime.
+  // Toggle between every 2nd and 4th number.
+  // (This is because every 6th odd number is divisible by 3.)
+  for (i = 5; i*i <= n; i += 6) {
+    if (((n % i) == 0 ) || ((n % (i + 2)) == 0) ) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+inline unsigned
+LeastSigBit(unsigned n)
+{ return n & ~(n - 1); }
+
+inline bool
+IsPowerOf2(unsigned n)
+{ return n != 0 && LeastSigBit(n) == n; }
+
+inline int
+FloorLog2(unsigned x)
+{
+  if (x == 0)
+    return -1;
+
+  int y = 0;
+
+  if (x & 0xffff0000) { y += 16; x >>= 16; }
+  if (x & 0x0000ff00) { y +=  8; x >>=  8; }
+  if (x & 0x000000f0) { y +=  4; x >>=  4; }
+  if (x & 0x0000000c) { y +=  2; x >>=  2; }
+  if (x & 0x00000002) { y +=  1; }
+
+  return y;
+}
+
+inline int
+CeilLog2(unsigned n)
+{ return FloorLog2(n-1)+1; }
+
+inline unsigned
+FloorPow2(unsigned n)
+{ return 1 << FloorLog2(n); }
+
+inline unsigned
+CeilPow2(unsigned n)
+{ return 1 << CeilLog2(n); }
+
+inline bool
+IsHex(char c)
+{ return (c >= '0' && c <= '9' ||
+          c >= 'A' && c <= 'F' ||
+          c >= 'a' && c <= 'f');
+}
+
+inline bool
+IsOct(char c)
+{ return (c >= '0' && c <= '7'); }
+
+inline bool
+IsDec(char c)
+{ return (c >= '0' && c <= '9'); }
+
+inline int
+Hex2Int(char c)
+{
+  if (c >= '0' && c <= '9')
+    return (c - '0');
+
+  if(c >= 'A' && c <= 'F')
+    return (c - 'A') + 10;
+
+  if (c >= 'a' && c <= 'f')
+    return (c - 'a') + 10;
+
+  return 0;
+}
+
+#endif // __INTMATH_H__