[Rd] 'ecdf': how about exploiting property that 'x' is sorted?

[Suharto Anggono Suharto Anggono]

In the code of function 'ecdf' di R (for example, version 2.15.2), input 'x' is sorted first. Because the values are sorted, same values are contiguous. So, how about using an approach as inside function 'rle'? Because missing values is removed by 'sort', it can be done like this.

i <- c(which(x[-1L] != x[-n]), n)
rval <- approxfun(x[i], i/n, ...)