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authorAdam Moss <moss@lindenlab.com>2009-03-09 23:42:07 +0000
committerAdam Moss <moss@lindenlab.com>2009-03-09 23:42:07 +0000
commit7573288ab3ede23f97bff2f5caefcb622e7e9842 (patch)
tree1429e7d758e282e123d31a21246603d0b9814273 /indra/llcommon/is_approx_equal_fraction.h
parent2d60d45aead0b49787fb8ad8b5a03614fe17c170 (diff)
svn merge -r113780:113785
svn+ssh://svn.lindenlab.com/svn/linden/branches/moss/gst3-t113732 QAR-1333 linux gstreamer compatibility improvements and ADD_BUILD_TEST improvements - combo merge
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+/**
+ * @file is_approx_equal_fraction.h
+ * @author Nat Goodspeed
+ * @date 2009-01-28
+ * @brief lltut.h uses is_approx_equal_fraction(). Moved to this header
+ * file in llcommon so we can use lltut.h for llcommon tests without
+ * making llcommon depend on llmath.
+ *
+ * $LicenseInfo:firstyear=2009&license=viewergpl$
+ * Copyright (c) 2009, Linden Research, Inc.
+ * $/LicenseInfo$
+ */
+
+#if ! defined(LL_IS_APPROX_EQUAL_FRACTION_H)
+#define LL_IS_APPROX_EQUAL_FRACTION_H
+
+#include "lldefs.h"
+#include <cmath>
+
+/**
+ * Originally llmath.h contained two complete implementations of
+ * is_approx_equal_fraction(), with signatures as below, bodies identical save
+ * where they specifically mentioned F32/F64. Unifying these into a template
+ * makes sense -- but to preserve the compiler's overload-selection behavior,
+ * we still wrap the template implementation with the specific overloaded
+ * signatures.
+ */
+template <typename FTYPE>
+inline BOOL is_approx_equal_fraction_impl(FTYPE x, FTYPE y, U32 frac_bits)
+{
+ BOOL ret = TRUE;
+ FTYPE diff = (FTYPE) fabs(x - y);
+
+ S32 diffInt = (S32) diff;
+ S32 diffFracTolerance = (S32) ((diff - (FTYPE) diffInt) * (1 << frac_bits));
+
+ // if integer portion is not equal, not enough bits were used for packing
+ // so error out since either the use case is not correct OR there is
+ // an issue with pack/unpack. should fail in either case.
+ // for decimal portion, make sure that the delta is no more than 1
+ // based on the number of bits used for packing decimal portion.
+ if (diffInt != 0 || diffFracTolerance > 1)
+ {
+ ret = FALSE;
+ }
+
+ return ret;
+}
+
+/// F32 flavor
+inline BOOL is_approx_equal_fraction(F32 x, F32 y, U32 frac_bits)
+{
+ return is_approx_equal_fraction_impl<F32>(x, y, frac_bits);
+}
+
+/// F64 flavor
+inline BOOL is_approx_equal_fraction(F64 x, F64 y, U32 frac_bits)
+{
+ return is_approx_equal_fraction_impl<F64>(x, y, frac_bits);
+}
+
+#endif /* ! defined(LL_IS_APPROX_EQUAL_FRACTION_H) */