[Performance] Why D's std.string.atoi is 4x slower than std.c.stdlib.atoi?

[Burton Radons]

Andrey Khropov wrote:
> -------------------------------------------------
> On my machine (P-M 1.7 Dothan) the mean times are:
> 
> D-StdLib:1695 ms elapsed (mean).
> C-StdLib:374 ms elapsed (mean).
> 
> Why is it so? What could be done?

It's because std.string.atoi is implemented simply with:

     return std.c.stdlib.atoi(toStringz(s));

The fault is toStringz - originally that operation tried to tell whether 
the string was NUL-terminated, but now it just allocates a copy.

Use std.conv.toInt instead, although from the looks of the 
implementation, that will be slightly slower as well.