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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() * added: Parser::InitCGamma()
initializing coefficients used when calculating the gamma (or factorial) function initializing coefficients used when calculating the gamma (or factorial) function
this speed up the next calculations 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 these coefficients will be calculated when needed
* added: option 'group_digits' to Conv struct * added: option 'group_digits' to Conv struct
you can set how many digits should be grouped 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): 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 ) uint FromString_ReadPartAfterComma( const char_type * & source, const Conv & conv, bool & value_read )
{ {
sint character; sint character;
uint c = 0, index = 1; uint c = 0, power = 0;
Big<exp, man> sum, part, power, old_value, base_( conv.base ); UInt<1> power_;
Big<exp, man> sum, base_(conv.base);
// we don't remove any white characters here // 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(); sum.SetZero();
for( ; true ; ++source, ++index ) for( ; sum.exponent.IsSign() || sum.exponent.IsZero() ; ++source )
{ {
if( conv.group!=0 && *source==static_cast<char>(conv.group) ) if( conv.group!=0 && *source==static_cast<char>(conv.group) )
continue; continue;
@ -5144,30 +5139,13 @@ private:
value_read = true; 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 // 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 ) if( power == 0 )
// after adding 'part' the value has not been changed c += 1;
// there's no sense to add any next parts
break;
} }
// we could break the parsing somewhere in the middle of the string, // 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 // we should set a correct value of 'source' now
for( ; Misc::CharToDigit(*source, conv.base) != -1 ; ++source ); for( ; Misc::CharToDigit(*source, conv.base) != -1 ; ++source );
power_ = power;
c += base_.Pow(power_);
c += sum.Div(base_);
c += Add(sum); c += Add(sum);
return (c==0)? 0 : 1; return (c==0)? 0 : 1;