1 files changed, 62 insertions, 0 deletions
diff --git a/src/utils/mathutils.h b/src/utils/mathutils.h
index 69267186c..3fa7ad002 100644
--- a/src/utils/mathutils.h
+++ b/src/utils/mathutils.h
@@ -24,6 +24,7 @@
 #define UTILS_MATHUTILS_H
 
 #include <string>
+#include <cmath>
 
 #include "localconsts.h"
 
@@ -63,6 +64,60 @@ static const uint16_t crc_table[256] =
     0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
 };
 
+static const int square_roots[1000] =
+{
+    0, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4,
+    4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6,
+    6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+    7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+    8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
+    10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
+    10,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,
+    11,11,11,11,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,
+    12,12,12,12,12,12,12,12,12,13,13,13,13,13,13,13,13,13,13,13,
+    13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,14,14,14,14,
+    14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,14,
+    14,14,14,14,14,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,
+    15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,16,16,16,16,
+    16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,
+    16,16,16,16,16,16,16,16,16,17,17,17,17,17,17,17,17,17,17,17,
+    17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,17,
+    17,17,17,17,18,18,18,18,18,18,18,18,18,18,18,18,18,18,18,18,
+    18,18,18,18,18,18,18,18,18,18,18,18,18,18,18,18,18,18,18,18,
+    18,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,
+    19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,
+    20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,
+    20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,
+    20,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,
+    21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,
+    21,21,21,21,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,
+    22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,
+    22,22,22,22,22,22,22,22,22,23,23,23,23,23,23,23,23,23,23,23,
+    23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,
+    23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,24,24,24,24,
+    24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,
+    24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,
+    24,24,24,24,24,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,
+    25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,
+    25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,26,26,26,26,
+    26,26,26,26,26,26,26,26,26,26,26,26,26,26,26,26,26,26,26,26,
+    26,26,26,26,26,26,26,26,26,26,26,26,26,26,26,26,26,26,26,26,
+    26,26,26,26,26,26,26,26,26,27,27,27,27,27,27,27,27,27,27,27,
+    27,27,27,27,27,27,27,27,27,27,27,27,27,27,27,27,27,27,27,27,
+    27,27,27,27,27,27,27,27,27,27,27,27,27,27,27,27,27,27,27,27,
+    27,27,27,27,28,28,28,28,28,28,28,28,28,28,28,28,28,28,28,28,
+    28,28,28,28,28,28,28,28,28,28,28,28,28,28,28,28,28,28,28,28,
+    28,28,28,28,28,28,28,28,28,28,28,28,28,28,28,28,28,28,28,28,
+    28,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,
+    29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,
+    29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,
+    30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,
+    30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,
+    30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,30,
+    30,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,
+    31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31
+};
+
 inline uint16_t getCrc16(const std::string &str) A_WARN_UNUSED;
 inline float fastInvSqrt(float x) A_WARN_UNUSED;
 inline float fastSqrt(const float x) A_WARN_UNUSED;
@@ -130,4 +185,11 @@ inline int powerOfTwo(const unsigned int input)
     return value;
 }
 
+inline int fastSqrtInt(const unsigned int n)
+{
+    if (n < 1000)
+        return square_roots[n];
+    return sqrt(n);
+}
+
 #endif  // UTILS_MATHUTILS_H