dd option of doing fuzzy equality tests.

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@27958 72102866-910b-0410-8b05-ffd578937521

ChangeLog

@@ -1,3 +1,13 @@
+2009-02-23  Richard Frith-Macdonald <rfm@gnu.org>
+
+	* Headers/Foundation/NSGeometry.h:
+	* Source/NSGeometry.m:
+	Inspired by Matt Rice's comments on NSEqualRects(), moved the
+	equality testing functions from the header to the implementation
+	file and added conditionally compiled code to allow us to do a
+	fuzzy equality test.  Still need to decide whether this is actually
+	the correct thing to do though.
+
 2009-02-22  Richard Frith-Macdonald <rfm@gnu.org>
 
 	* Source/NSUnarchiver.m:

Headers/Foundation/NSGeometry.h

@@ -423,41 +423,18 @@ NSIntersectionRect (NSRect aRect, NSRect bRect)
 
 /** Test geometric relationships... **/
 
-GS_GEOM_SCOPE BOOL
+/** Returns 'YES' iff aRect's and bRect's origin and size are the same. */
+GS_EXPORT BOOL
 NSEqualRects(NSRect aRect, NSRect bRect) GS_GEOM_ATTR;
 
-/** Returns 'YES' iff aRect's and bRect's origin and size are the same. */
-GS_GEOM_SCOPE BOOL
-NSEqualRects(NSRect aRect, NSRect bRect)
-{
-  return ((NSMinX(aRect) == NSMinX(bRect))
-          && (NSMinY(aRect) == NSMinY(bRect))
-          && (NSWidth(aRect) == NSWidth(bRect))
-          && (NSHeight(aRect) == NSHeight(bRect))) ? YES : NO;
-}
-
-GS_GEOM_SCOPE BOOL
-NSEqualSizes(NSSize aSize, NSSize bSize) GS_GEOM_ATTR;
-
 /** Returns 'YES' iff aSize's and bSize's width and height are the same. */
-GS_GEOM_SCOPE BOOL
-NSEqualSizes(NSSize aSize, NSSize bSize)
-{
-  return ((aSize.width == bSize.width)
-          && (aSize.height == bSize.height)) ? YES : NO;
-}
-
-GS_GEOM_SCOPE BOOL
-NSEqualPoints(NSPoint aPoint, NSPoint bPoint) GS_GEOM_ATTR;
+GS_EXPORT BOOL
+NSEqualSizes(NSSize aSize, NSSize bSize) GS_GEOM_ATTR;
 
 /** Returns 'YES' iff aPoint's and bPoint's x- and y-coordinates
  * are the same. */
-GS_GEOM_SCOPE BOOL
-NSEqualPoints(NSPoint aPoint, NSPoint bPoint)
-{
-  return ((aPoint.x == bPoint.x)
-          && (aPoint.y == bPoint.y)) ? YES : NO;
-}
+GS_EXPORT BOOL
+NSEqualPoints(NSPoint aPoint, NSPoint bPoint) GS_GEOM_ATTR;
 
 GS_GEOM_SCOPE BOOL
 NSMouseInRect(NSPoint aPoint, NSRect aRect, BOOL flipped) GS_GEOM_ATTR;

Source/NSGeometry.m

@@ -36,6 +36,7 @@
 
 #include "config.h"
 #include <math.h>
+#include <stdlib.h>
 #include "GNUstepBase/preface.h"
 #include "Foundation/NSString.h"
 #include "Foundation/NSGeometry.h"
@@ -388,3 +389,109 @@ NSRectFromString(NSString* string)
     }
 }
 
+/* Tests for equality of floats/doubles.
+ * WARNING assumes the values are in the standard IEEE format ...
+ * this may not be true on all systems, though afaik it is the case
+ * on all systems we target.
+ *
+ * We use integer arithmetic for speed, assigning the float/double
+ * to an integer of the same size and then converting any negative
+ * values to twos-complement integer values so that a simple integer
+ * comparison can be done.
+ *
+ * MAX_ULP specified the number of Units in the Last Place by which
+ * the two values may differ and still be considered equal.  A value
+ * of zero means that the two numbers must be identical.
+ *
+ * The way that infinity is represented means that it will be considered
+ * equal to MAX_FLT (or MAX_DBL) unless we are doing an exact comparison
+ * with MAX_ULP set to zero.
+ *
+ * The implementation will also treat two NaN values as being equal, which
+ * is technically wrong ... but is it worth adding a check for that?
+ */
+#define	MAX_ULP	0
+static inline BOOL
+almostEqual(CGFloat A, CGFloat B)
+{
+#if	MAX_ULP == 0
+  return (A == B) ? YES : NO;
+#else	/* MAX_UPL == 0 */
+#if	defined(CGFLOAT_IS_DBL)
+  union {int64_t i; double d;} valA, valB;
+
+  valA.d = A;
+  valB.d = B;
+#if	GS_SIZEOF_LONG == 8
+  if (valA.i < 0)
+    {
+      valA.i = 0x8000000000000000L - valA.i;
+    }
+  if (valB.i < 0)
+    {
+      valB.i = 0x8000000000000000L - valB.i;
+    }
+  if (labs(valA.i - valB.i) <= MAX_ULP)
+    {
+      return YES;
+    }
+#else	/* GS_SIZEOF_LONG == 8 */
+  if (valA.i < 0)
+    {
+      valA.i = 0x8000000000000000LL - valA.i;
+    }
+  if (valB.i < 0)
+    {
+      valB.i = 0x8000000000000000LL - valB.i;
+    }
+  if (llabs(valA.i - valB.i) <= MAX_ULP)
+    {
+      return YES;
+    }
+#endif	/* GS_SIZEOF_LONG == 8 */
+  return NO;
+#else	/* DEFINED(CGFLOAT_IS_DBL) */
+  union {int32_t i; float f;} valA, valB;
+
+  valA.f = A;
+  if (valA.i < 0)
+    {
+      valA.i = 0x80000000 - valA.i;
+    }
+  valB.f = B;
+  if (valB.i < 0)
+    {
+      valB.i = 0x80000000 - valB.i;
+    }
+  if (abs(valA.i - valB.i) <= MAX_ULP)
+    {
+      return YES;
+    }
+  return NO;
+#endif	/* DEFINED(CGFLOAT_IS_DBL) */
+#endif	/* MAX_UPL == 0 */
+}
+
+BOOL
+NSEqualRects(NSRect aRect, NSRect bRect)
+{
+  return (almostEqual(NSMinX(aRect), NSMinX(bRect))
+    && almostEqual(NSMinY(aRect), NSMinY(bRect))
+    && almostEqual(NSWidth(aRect), NSWidth(bRect))
+    && almostEqual(NSHeight(aRect), NSHeight(bRect))) ? YES : NO;
+}
+
+BOOL
+NSEqualSizes(NSSize aSize, NSSize bSize)
+{
+  return (almostEqual(aSize.width, bSize.width)
+    && almostEqual(aSize.height, bSize.height)) ? YES : NO;
+}
+
+BOOL
+NSEqualPoints(NSPoint aPoint, NSPoint bPoint)
+{
+  return (almostEqual(aPoint.x, bPoint.x)
+    && almostEqual(aPoint.y, bPoint.y)) ? YES : NO;
+}
+