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removed: Big::AboutEqualWithoutSign() 

it was broken (it lacks the case when either 'this' or 'ss2' is zero)


git-svn-id: svn://ttmath.org/publicrep/ttmath/trunk@206 e52654a7-88a9-db11-a3e9-0013d4bc506e
This commit is contained in:
Tomasz Sowa 2009-10-12 23:27:14 +00:00
parent e765fba8a1
commit 32ebbbfd9e
1 changed files with 0 additions and 133 deletions
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133
ttmath/ttmathbig.h
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@ -4155,139 +4155,6 @@ public:
}
/*!
this method compares this and ss2 by ingoring some nBitsToIgnore last bits from mantissas
if nBitsToIgnore is 0 then the method is equivalent to EqualWithoutSign() method
(signs are not checked, we don't check the NaN flag too)
sample:
Big<1,1> a, b;
a = " 1234.5678";
b = "-1234.5677999";
// binary a: 10011010010.100100010101101101010
// binary b: -10011010010.100100010101101101000
// two last bits are different
if( a.AboutEqualWithoutSign(b, 2) ) // the result is true
std::cout << "true" << std::endl;
***warning broken*** doesn't work if 'this' or 'ss2' is zero
*/
bool AboutEqualWithoutSign(const Big<exp,man> & ss2, uint ignore_bits = 4) const
{
TTMATH_ASSERT( ignore_bits < man*TTMATH_BITS_PER_UINT )
if( IsZero() && ss2.IsZero() )
return true;
if( exponent == ss2.exponent )
return AboutEqualExpEqual(mantissa, ss2.mantissa, ignore_bits);
UInt<exp> exp_diff;
exp_diff = exponent;
exp_diff.Sub(ss2.exponent);
if( exp_diff == 1 )
{
// exponent is > ss2.exponent
UInt<man> man_diff(mantissa);
UInt<man> man_temp(ss2.mantissa);
man_temp.Rcr(1, 0);
man_diff.Sub(man_temp);
return AboutEqualZero(man_diff, ignore_bits);
}
else
if( exp_diff == -1 )
{
// exponent is < ss2.exponent
UInt<man> man_diff(ss2.mantissa);
UInt<man> man_temp(mantissa);
man_temp.Rcr(1, 0);
man_diff.Sub(man_temp);
return AboutEqualZero(man_diff, ignore_bits);
}
// exp_diff is different from zero, one or minus one
return false;
}
private:
/*!
an auxiliary method for calculating AboutEqualWithoutSign()
we're using it when exponent is equal ss2.exponent
*/
bool AboutEqualExpEqual(const UInt<man> & man1, const UInt<man> & man2, uint ignore_bits) const
{
uint words = ignore_bits / TTMATH_BITS_PER_UINT;
uint bits = ignore_bits % TTMATH_BITS_PER_UINT;
uint i;
if( bits == 0 )
{
i = words;
}
else
{
i = words + 1;
uint mask = TTMATH_UINT_MAX_VALUE << bits;
if( (man1.table[words] & mask) != (man2.table[words] & mask) )
return false;
}
for( ; i<man ; ++i )
{
if( man1.table[i] != man2.table[i] )
return false;
}
return true;
}
/*!
an auxiliary method for calculating AboutEqualWithoutSign()
*/
bool AboutEqualZero(const UInt<man> & man_diff, uint ignore_bits) const
{
uint words = ignore_bits / TTMATH_BITS_PER_UINT;
uint bits = ignore_bits % TTMATH_BITS_PER_UINT;
uint i;
if( bits == 0 )
{
i = words;
}
else
{
i = words + 1;
uint mask = TTMATH_UINT_MAX_VALUE << bits;
if( (man_diff.table[words] & mask) != 0 )
return false;
}
for( ; i<man ; ++i )
{
if( man_diff.table[i] != 0 )
return false;
}
return true;
}
public:
bool operator<(const Big<exp,man> & ss2) const
{
if( IsSign() && !ss2.IsSign() )