Re: Reading and writing a big file in Ada (GNAT) on Windows XP

["(see below)" <yaldnif.w@blueyonder.co.uk>]

On 28/4/07 06:03, in article 0hj5339mjmond132qhbn2o01unurs61lbj@4ax.com,
"Fionn Mac Cumhaill" <invisible@hiding.from.spam> wrote:

> I have written a very simple program that runs  on a Windows XP
> machine. (Pentium D , I don't remember the clock speed, it is in
> middle of Pentium D clock speeds, 2 Gb memory) It is compiled with the
> MinGW GNAT 3.4.5 Ada compiler.
> 
> All it does is read lines in a loop from a text file with
> Ada.Text_IO.Get_Line, does minor modifications on about 80% of the
> lines that it reads, and writes the lines to an output file with
> Put_Line. 
...
> The problem is that the input file has more than 10 million lines of
> text in it. The program works perfectly, but takes about 5 hours to
> run. The Cygwin version of wc can count the lines in the input file in
> less than one minute.

I have an assembler that reads source code and writes an equal number of
lines of object code, all I/O done using Ada.Text_IO.{Get_Line, Put(str)}.

That takes less than 6 sec CPU time, on a Mac Powerbook 1.67GHz laptop,
for 1_000_000 lines of input, giving a performance of around 10 million
lines per minute - around 300 times faster than you are getting - so I think
it unlikely that Ada.Text_IO is your problem.

-- 
Bill Findlay
<surname><forename> chez blueyonder.co.uk