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changed: Big::FromString_ReadPartAfterComma() 

now we're reading the all part as integer and 
         at the end we're dividing it by (base ^ how_many_digits_there_were)

         it's faster and should be a little accurate in some cases



git-svn-id: svn://ttmath.org/publicrep/ttmath/trunk@342 e52654a7-88a9-db11-a3e9-0013d4bc506e
This commit is contained in:
Tomasz Sowa 2011-02-27 18:13:32 +00:00
parent e8daa77d75
commit 2e192969b0
2 changed files with 14 additions and 32 deletions
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3
CHANGELOG
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@ -1,4 +1,4 @@
Version 0.9.3 prerelease (2011.01.30):
Version 0.9.3 prerelease (2011.02.27):
* added: Parser::InitCGamma()
initializing coefficients used when calculating the gamma (or factorial) function
this speed up the next calculations
@ -6,6 +6,7 @@ Version 0.9.3 prerelease (2011.01.30):
these coefficients will be calculated when needed
* added: option 'group_digits' to Conv struct
you can set how many digits should be grouped
* changed: small optimizations in UInt::ToString() and Big::FromString()
Version 0.9.2 (2010.09.23):

43
ttmath/ttmathbig.h
View File

@ -5120,19 +5120,14 @@ private:
uint FromString_ReadPartAfterComma( const char_type * & source, const Conv & conv, bool & value_read )
{
sint character;
uint c = 0, index = 1;
Big<exp, man> sum, part, power, old_value, base_( conv.base );
uint c = 0, power = 0;
UInt<1> power_;
Big<exp, man> sum, base_(conv.base);
// we don't remove any white characters here
// this is only to avoid getting a warning about an uninitialized object 'old_value' which GCC reports
// (in fact we will initialize it later when the condition 'testing' is fulfilled)
old_value.SetZero();
power.SetOne();
sum.SetZero();
for( ; true ; ++source, ++index )
for( ; sum.exponent.IsSign() || sum.exponent.IsZero() ; ++source )
{
if( conv.group!=0 && *source==static_cast<char>(conv.group) )
continue;
@ -5144,30 +5139,13 @@ private:
value_read = true;
part = character;
if( power.Mul( base_ ) )
// there's no sens to add the next parts, but we can't report this
// as an error (this is only inaccuracy)
break;
if( part.Div( power ) )
break;
// every 5 iteration we make a test whether the value will be changed or not
// (character must be different from zero to this test)
bool testing = (character != 0 && (index % 5) == 0);
if( testing )
old_value = sum;
// there actually shouldn't be a carry here
c += sum.Add( part );
c += sum.Mul(base_);
c += sum.Add(character);
power += 1;
if( testing && old_value == sum )
// after adding 'part' the value has not been changed
// there's no sense to add any next parts
break;
if( power == 0 )
c += 1;
}
// we could break the parsing somewhere in the middle of the string,
@ -5175,6 +5153,9 @@ private:
// we should set a correct value of 'source' now
for( ; Misc::CharToDigit(*source, conv.base) != -1 ; ++source );
power_ = power;
c += base_.Pow(power_);
c += sum.Div(base_);
c += Add(sum);
return (c==0)? 0 : 1;