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poor performance while processing a file one byte a time

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Hello,

I am processing some files using php. Basically I read every byte of
the file and perform a simple operation on it to compute a sum.

My initial implementation was in C, but now I am trying re-doing the
same in PHP. This is how my PHP code looks like:


function fn($fname) {
  $fd = fopen($fname, 'rb');
  if ($fd === false) return(0);

  $result = 0;

  while (!feof($fd)) {

    $buff = fread($fd, 1024 * 1024);

    foreach (str_split($buff) as $b) {
      $result += ord($b);
      $result &= 0xffff;
    }
  }

  fclose($fd);
  return($result);
}

It works, but it is really slow (approximately 100x slower than the
original C code). I know that I should not expect much performance
from interpreted PHP code, but still - is there any trick I could use to
speed this up?

I have also tried to replace str_split() and ord() with unpack('C*'),
but it was even slower. Anything else I could try?


Mateusz

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poor performance while processing a file one byte a time Mateusz Viste <mateusz@xyz.invalid> - 2022-01-20 15:16 +0100
  Re: poor performance while processing a file one byte a time John-Paul Stewart <jpstewart@personalprojects.net> - 2022-01-20 11:08 -0500
    Re: poor performance while processing a file one byte a time Mateusz Viste <mateusz@xyz.invalid> - 2022-01-20 17:23 +0100
      Re: poor performance while processing a file one byte a time John-Paul Stewart <jpstewart@personalprojects.net> - 2022-01-20 12:38 -0500
        Re: poor performance while processing a file one byte a time Mateusz Viste <mateusz@xyz.invalid> - 2022-01-20 19:49 +0100
    Re: poor performance while processing a file one byte a time Mateusz Viste <mateusz@xyz.invalid> - 2022-01-20 17:37 +0100
      Re: poor performance while processing a file one byte a time John-Paul Stewart <jpstewart@personalprojects.net> - 2022-01-20 12:41 -0500
        Re: poor performance while processing a file one byte a time Mateusz Viste <mateusz@xyz.invalid> - 2022-01-20 19:47 +0100
  Re: poor performance while processing a file one byte a time Arno Welzel <usenet@arnowelzel.de> - 2022-01-20 19:23 +0100
    Re: poor performance while processing a file one byte a time Mateusz Viste <mateusz@xyz.invalid> - 2022-01-20 19:45 +0100
      Re: poor performance while processing a file one byte a time Arno Welzel <usenet@arnowelzel.de> - 2022-01-20 20:27 +0100

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