C++ convert to radix 64

[Andariel666]

Hi epvpers!

I have a question about converting numbers (decimal) to radix 64.
Tell the truth the conversion is OK, but I have problem with converting it back.

static long unsigned int base64dec(const char *text)
{
	return strtoull(text, NULL, 64);
}

The code above works perfectly until base 36, because 'strtoull' support only up to 36.


But I would like to convert it back to decimal.

What is the better way to do that?


Thank you.

[ƬheGame]

Originally Posted by Andariel666

Hi epvpers!

I have a question about converting numbers (decimal) to radix 64.
Tell the truth the conversion is OK, but I have problem with converting it back.

static long unsigned int base64dec(const char *text)
{
	return strtoull(text, NULL, 64);
}

The code above works perfectly until base 36, because 'strtoull' support only up to 36.


But I would like to convert it back to decimal.

What is the better way to do that?


Thank you.

Here you go:

[Andariel666]

Thx, but it isn't right for me.

This source encode everything to base64.
But I would like to convert only DECIMAL NUMBERS to radix 64. This is a simply number system conversion. The encoding works fine, but the decoding doesn't works well....

Here are two examples:

Good for me:

Bad for me:

I think base64 encoding isn't the same as convert a number to radix 64.

[ƬheGame]

You can do it like that:

the base64 string cant be longer than 5 bc. a integer wouldnt have enought "place" to store a higher value

if you want to save the result in a string you just have to modify this example a little bit. Then you can convert base64 strings longer than 5

[Andariel666]

I would be great, but im not familiar with C#.
Yes, the is an other problem, because I would like to convert very big numbers to short them with the conversion.

May be I could use GMP or MPIR handling the bug numbers.

[ƬheGame]

Originally Posted by Andariel666

I would be great, but im not familiar with C#.
Yes, the is an other problem, because I would like to convert very big numbers to short them with the conversion.

May be I could use GMP or MPIR handling the bug numbers.

Its 90% the same code in c++, c, python, java etc.
You just need to adjust it.

[Andariel666]

That's true, to convert it C++ not so difficult, but there is a bigger problem.
That code can handle only 32 bit integers. This is too small for my purpose.
I would like to convert for example 200 digited number. That the problem....

[ƬheGame]

Originally Posted by Andariel666

That's true, to convert it C++ not so difficult, but there is a bigger problem.
That code can handle only 32 bit integers. This is too small for my purpose.
I would like to convert for example 200 digited number. That the problem....

This will be impossible without an additional library.

[Andariel666]

GNP solved the problem.