From 91c88a4ec7e6d0b1ed675d132033efebd1b1d2c4 Mon Sep 17 00:00:00 2001
From: Kevin Larke <kevin@larke.org>
Date: Fri, 22 May 2015 13:56:02 -0700
Subject: [PATCH] cmMath.h/c : Added cmIsCloseX().

---
 cmMath.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 cmMath.h |  7 +++++++
 2 files changed, 55 insertions(+)

diff --git a/cmMath.c b/cmMath.c
index 2ac7a82..028354e 100644
--- a/cmMath.c
+++ b/cmMath.c
@@ -419,3 +419,51 @@ double   cmRandDouble( double min, double max )
   double offs = max - min;
   return min + cmMax(0,cmMin(offs,(offs * (double)rand() / RAND_MAX)));
 }
+
+
+//=================================================================
+// Base on: http://stackoverflow.com/questions/3874627/floating-point-comparison-functions-for-c-sharp
+
+bool cmIsCloseD( double x0, double x1, double eps )
+{
+  double d = fabs(x0-x1);
+  
+  if( x0 == x1 )
+    return true;
+
+  if( x0==0 || x1==0 || d<DBL_MIN )
+    return d < (eps * DBL_MIN);
+
+  return (d / cmMin( fabs(x0) + fabs(x1), DBL_MAX)) < eps;
+}
+
+bool cmIsCloseF( float  x0, float  x1, double  eps_d )
+{
+  float eps = (float)eps_d;
+  float d = fabsf(x0-x1);
+  
+  if( x0 == x1 )
+    return true;
+
+  if( x0==0 || x1==0 || d<FLT_MIN )
+    return d < (eps * FLT_MIN);
+
+  return (d / cmMin( fabsf(x0) + fabsf(x1), FLT_MAX)) < eps;
+}
+
+bool cmIsCloseI( int x0, int x1, double eps )
+{
+  if( x0 == x1 )
+    return true;
+  
+  return abs(x0-x1)/(abs(x0)+abs(x1)) < eps;
+}
+
+
+bool cmIsCloseU( unsigned x0, unsigned x1, double eps )
+{
+  if( x0 == x1 )
+    return true;
+  
+  return abs(x0-x1)/(x0+x1) < eps;
+}
diff --git a/cmMath.h b/cmMath.h
index 4d3697f..b0d047c 100644
--- a/cmMath.h
+++ b/cmMath.h
@@ -67,4 +67,11 @@ int      cmRandInt( int min, int max );
 unsigned cmRandUInt( unsigned min, unsigned max );
 float    cmRandFloat( float min, float max );
 double   cmRandDouble( double min, double max );
+
+//=================================================================
+bool cmIsCloseD( double   x0, double   x1, double eps );
+bool cmIsCloseF( float    x0, float    x1, double eps );
+bool cmIsCloseI( int      x0, int      x1, double eps );
+bool cmIsCloseU( unsigned x0, unsigned x1, double eps );
+
 #endif