Oh no, very sorry, that wasn't the problem with negative numbers... it
would just skip that digit. I wonder what is my problem then..
On Jun 14, 11:44 am, Parch <[EMAIL PROTECTED]> wrote:
> I had a bug today because Integer parsing wasn't detecting any errors
> while parsing a string with leading space: e.g. " -152". Once I
> realised that, I noticed that integer parsing for negative numbers is
> like totally broken as well, since it silently treats the '-' sign as
> a digit with value == radix...
>
> Suggesting a bug fix + a couple error detection changes to the code.
>
> Original Code:
>
> template <class T>
> static Integer StringToInteger(const T *str)
> {
> int radix;
> // GCC workaround
> // std::char_traits<wchar_t>::length() not defined in GCC 3.2 and
> STLport 4.5.3
> unsigned int length;
> for (length = 0; str[length] != 0; length++) {}
>
> Integer v;
>
> if (length == 0)
> return v;
>
> switch (str[length-1])
> {
> case 'h':
> case 'H':
> radix=16;
> break;
> case 'o':
> case 'O':
> radix=8;
> break;
> case 'b':
> case 'B':
> radix=2;
> break;
> default:
> radix=10;
> }
>
> if (length > 2 && str[0] == '0' && str[1] == 'x')
> radix = 16;
>
> for (unsigned i=0; i<length; i++)
> {
> int digit;
>
> if (str[i] >= '0' && str[i] <= '9')
> digit = str[i] - '0';
> else if (str[i] >= 'A' && str[i] <= 'F')
> digit = str[i] - 'A' + 10;
> else if (str[i] >= 'a' && str[i] <= 'f')
> digit = str[i] - 'a' + 10;
> else
> digit = radix;
>
> if (digit < radix)
> {
> v *= radix;
> v += digit;
> }
> }
>
> if (str[0] == '-')
> v.Negate();
>
> return v;
>
> }
>
> Some changes:
>
> template <class T>
> static Integer StringToInteger(const T *str)
> {
> int radix;
> // GCC workaround
> // std::char_traits<wchar_t>::length() not defined in GCC 3.2 and
> STLport 4.5.3
> unsigned int length;
> for (length = 0; str[length] != 0; length++) {}
>
> Integer v;
>
> //Should this really be allowed??
> if (length == 0)
> return v;
>
> switch (str[length-1])
> {
> case 'h':
> case 'H':
> radix=16;
> length--; //don't parse the radix later
> break;
> case 'o':
> case 'O':
> radix=8;
> length--;
> break;
> case 'b':
> case 'B':
> radix=2;
> length--;
> break;
> default:
> if( str[length-1] >= '0' && str[length-1] <= '9' )
> radix=10;
> else
> throw "Invalid radix in integer string
> representation"; //something
> to this effect
> }
>
> if (length == 0)
> throw "Radix-only integer string representation illegal"; //
> something to this effect
>
> if (length > 1 && str[0] == '-'){
> v.Negate();
> str++;
> length--;
> }
> else if (length > 2 && str[0] == '0' && str[1] == 'x'){
> radix = 16;
> str += 2;
> length -= 2;
> }
>
> for (unsigned i=0; i<length; i++)
> {
> int digit;
>
> if (str[i] >= '0' && str[i] <= '9')
> digit = str[i] - '0';
> else if (str[i] >= 'A' && str[i] <= 'F')
> digit = str[i] - 'A' + 10;
> else if (str[i] >= 'a' && str[i] <= 'f')
> digit = str[i] - 'a' + 10;
> else
> digit = radix;
>
> if (digit < radix)
> {
> v *= radix;
> v += digit;
> }
> else throw "Invalid digit parsing integer from string";
> //something
> to this effect
> }
>
> return v;
>
> }
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the "Crypto++ Users"
Google Group.
To unsubscribe, send an email to [EMAIL PROTECTED]
More information about Crypto++ and this group is available at
http://www.cryptopp.com.
-~----------~----~----~----~------~----~------~--~---
