From fcd5a47d8c62a036d43298b102eb9d9371e1dbdd Mon Sep 17 00:00:00 2001
From: jules <jules@juce.com>
Date: Wed, 11 Jan 2017 08:50:16 +0000
Subject: [PATCH] Added a bit-twiddling helper method: findHighestSetBit()

---
 modules/juce_core/maths/juce_BigInteger.cpp   | 38 +++++++++----------
 modules/juce_core/maths/juce_MathsFunctions.h | 12 ++++--
 2 files changed, 28 insertions(+), 22 deletions(-)

diff --git a/modules/juce_core/maths/juce_BigInteger.cpp b/modules/juce_core/maths/juce_BigInteger.cpp
index c0aab6228b..fa973a4be6 100644
--- a/modules/juce_core/maths/juce_BigInteger.cpp
+++ b/modules/juce_core/maths/juce_BigInteger.cpp
@@ -33,26 +33,26 @@ namespace
     inline uint32 bitToMask  (const int bit) noexcept           { return (uint32) 1 << (bit & 31); }
     inline size_t bitToIndex (const int bit) noexcept           { return (size_t) (bit >> 5); }
     inline size_t sizeNeededToHold (int highestBit) noexcept    { return (size_t) (highestBit >> 5) + 1; }
+}
 
-    inline int highestBitInInt (uint32 n) noexcept
-    {
-        jassert (n != 0); // (the built-in functions may not work for n = 0)
+int findHighestSetBit (uint32 n) noexcept
+{
+    jassert (n != 0); // (the built-in functions may not work for n = 0)
 
-      #if JUCE_GCC || JUCE_CLANG
-        return 31 - __builtin_clz (n);
-      #elif JUCE_MSVC
-        unsigned long highest;
-        _BitScanReverse (&highest, n);
-        return (int) highest;
-      #else
-        n |= (n >> 1);
-        n |= (n >> 2);
-        n |= (n >> 4);
-        n |= (n >> 8);
-        n |= (n >> 16);
-        return countBitsInInt32 (n >> 1);
-      #endif
-    }
+  #if JUCE_GCC || JUCE_CLANG
+    return 31 - __builtin_clz (n);
+  #elif JUCE_MSVC
+    unsigned long highest;
+    _BitScanReverse (&highest, n);
+    return (int) highest;
+  #else
+    n |= (n >> 1);
+    n |= (n >> 2);
+    n |= (n >> 4);
+    n |= (n >> 8);
+    n |= (n >> 16);
+    return countNumberOfBits (n >> 1);
+  #endif
 }
 
 //==============================================================================
@@ -393,7 +393,7 @@ int BigInteger::getHighestBit() const noexcept
 
     for (int i = (int) bitToIndex (highestBit); i >= 0; --i)
         if (uint32 n = values[i])
-            return highestBitInInt (n) + (i << 5);
+            return findHighestSetBit (n) + (i << 5);
 
     return -1;
 }
diff --git a/modules/juce_core/maths/juce_MathsFunctions.h b/modules/juce_core/maths/juce_MathsFunctions.h
index 29bcc6a55b..dd416aeeb9 100644
--- a/modules/juce_core/maths/juce_MathsFunctions.h
+++ b/modules/juce_core/maths/juce_MathsFunctions.h
@@ -452,7 +452,7 @@ inline int roundToInt (int value) noexcept
     This is a slightly slower and slightly more accurate version of roundDoubleToInt(). It works
     fine for values above zero, but negative numbers are rounded the wrong way.
 */
-inline int roundToIntAccurate (const double value) noexcept
+inline int roundToIntAccurate (double value) noexcept
 {
    #ifdef __INTEL_COMPILER
     #pragma float_control (pop)
@@ -472,7 +472,7 @@ inline int roundToIntAccurate (const double value) noexcept
     even numbers will be rounded up or down differently. For a more accurate conversion,
     see roundDoubleToIntAccurate().
 */
-inline int roundDoubleToInt (const double value) noexcept
+inline int roundDoubleToInt (double value) noexcept
 {
     return roundToInt (value);
 }
@@ -487,7 +487,7 @@ inline int roundDoubleToInt (const double value) noexcept
     rounding values whose floating point component is exactly 0.5, odd numbers and
     even numbers will be rounded up or down differently.
 */
-inline int roundFloatToInt (const float value) noexcept
+inline int roundFloatToInt (float value) noexcept
 {
     return roundToInt (value);
 }
@@ -512,6 +512,12 @@ inline int nextPowerOfTwo (int n) noexcept
     return n + 1;
 }
 
+/** Returns the index of the highest set bit in a (non-zero) number.
+    So for n=3 this would return 1, for n=7 it returns 2, etc.
+    An input value of 0 is illegal!
+*/
+int findHighestSetBit (uint32 n) noexcept;
+
 /** Returns the number of bits in a 32-bit integer. */
 inline int countNumberOfBits (uint32 n) noexcept
 {