[R] GMP help - converting rosetta RSA-code to R

[Jeff Newmiller]

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As far as I can see, the gmp package does not currently support a raw 
interface to create bigz values. Here is my workaround:

####
plaintext <- "Rossetta Code"
stringtoasciihex <- function( s ) {
   vs <- strsplit( s, "", fixed = TRUE )[[ 1 ]]
   asc <- sapply( vs, function( C ) as.character( charToRaw( C ) ) )
   paste( c( "0x", asc ), collapse="" )
}
gmp::as.bigz( stringtoasciihex( plaintext ) )
###

On Sat, 17 Aug 2019, Martin M?ller Skarbiniks Pedersen wrote:

> Hi,
>    I am trying to make a R version a RosettaCode task involving big number.
>    More precise, I am trying to convert the c-solution
> http://rosettacode.org/wiki/RSA_code#C
> to R.
>
>   These two lines in C gives me problems:
> const char *plaintext = "Rossetta Code";
> mpz_import(pt, strlen(plaintext), 1, 1, 0, 0, plaintext);
>
> I have tried:
> library(gmp)
> plaintext <- "Rossetta Code"
> as.bigz(charToRaw(plaintext))
>
> and
> library(gmp)
> plaintext <- "Rossetta Code
> as.big(split(plaintext,""))
>
> Thanks for any help/suggestions
>
> Regards
> Martin M. S. Pedersen
>
> 	[[alternative HTML version deleted]]
>
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