[Jprogramming] ASCII bytes to string

[bill lam]

The relatively poor performance of the ruby program seems to be a result of 
looping writing one byte each time. Can ruby interpreter detect and optimize 
that loop, or you have to reprogram it for a fair comparison.


William James wrote:
> At Mon Sep 24 01:01:12 HKT 2007, Joey K Tuttle wrote:
> 
>> At 02:53  -0700 2007/09/23, William James wrote:
>>> Bjorn Helgason wrote:
>>>
>>>>    65 66 67{a.
>>> Thanks.  I needed this to convert a simple program that
>>> was posted on the Ruby newsgroup to J.
>>>
>>> Here's a cleaned up Ruby version.
>>>
>>> def scramble( fname )
>>>   _fname = fname + ".scrambled"
>>>   data = IO.read( fname )
>>>   File.open(_fname, "wb"){|ff|
>>>     data.each_byte{|c| ff.write((c | 0x80).chr) }
>>>   }
>>> end
>>>
>>> Here's my J version.
>>>
>>> read =: 1!:1
>>> write =: 1!:2
>>> scramble =: verb define
>>> ((128 (23 b.) a. i. read <y) { a. ) write <y,'.scrambled'
>>> )
>>>
>>> The J program is about 24 times as fast.
>>> The version I wrote in FreeBasic is 9 times as fast as J.
>>>
>> Interesting - what did your FreeBasic version look like?
> 
> It's very verbose; the language is designed to be quite
> compatible with Microsoft's QBasic, although it has pointers and
> C-style macros.  The executable is 27,648 bytes. (I hope we won't
> be tarred and feathered for being so off topic.)
> 
> 
> ' The comment character (') is almost invisible.
> sub scramble( filename as string )
>   dim as integer  in_handle, out_handle, i, size
>   dim bytes(1 to 4096) as byte
> 
>   in_handle = freefile
>   open filename for binary  access read  as in_handle
>   out_handle = freefile
>   open filename & ".scrambled" for binary access write as out_handle
>   while not eof( in_handle )
>     size = seek( in_handle )
>     get #in_handle, , bytes()
>     size = seek( in_handle ) - size
>     for i = 1 to size
>       bytes(i) = bytes(i) or &h80
>     next
>     put #out_handle, , bytes(1), size
>   wend
>   close  '\ Caution. Closes all open files.
> end sub
> 
> dim t as double
> t = timer
> scramble "words"
> print timer - t
> 
> 
> 
>        
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-- 
regards,
bill