Re: Slower than Python

[Steven Schveighoffer]

On Fri, 01 Mar 2013 16:28:08 -0500, cvk012c  
<cvk0...@motorolasolutions.com> wrote:

On my hardware with -inline options it now takes about 15 secs which is  
still slower than Python but with both -inline and -noboundscheck it  
takes 13 secs and finally beats Python.
But I still kind of disappointed because I expected a much better  
performance boost and got only 7%. Counting that Python is not the  
fastest scripting language I think that similar Perl and Java scripts  
will outperform D easily.
Thanks Andrei and simendsjo for a quick response though.

Phobos kind of refuses to treat strings like arrays of characters, it  
insists on decoding.

With DMD and a hand-written splitter, it takes 6 seconds instead of 10 on  
my system (64-bit macosx).

struct MySplitter
{
    private string s;
    private string source;
    this(string src)
    {
        source = src;
        popFront();
    }

    @property string front()
    {
        return s;
    }

    @property bool empty()
    {
        return s.ptr == null;
    }

    void popFront()
    {
        s = source;
        if(!source.length)
        {
            source = null;
        }
        else
        {
            size_t i = 0;
            bool found = false;
            for(; i + 1 < source.length; i++)
            {
                if(source[i] == '\r' && source[i + 1] == '\n')
                {
                    found = true;
                    break;
                }
            }
            s = source[0..i];
            if(found)
                source = source[i + 2..$];
            else
                source = source[$..$];
        }
    }
}

I'm sure splitter could be optimized to do the same thing I'm doing.

Probably can reduce that a bit using pointers instead of strings.

-Steve