Question

So I am doing a small experiment for myself, a script to read the php errors’ log file (with SplFileObject) and output it formatted on the browser.

I though it would be more logic to display it in reversed order (the latest errors on top).
To use the “normal” order I would just display each line and call $file->next(); to move the pointer, but as I’m doing it the other way around, and there’s not a prev() or previous() method as far as I know, the only way I found was using seek():

for($i = $lines_total - $start_at; $i > $lines_total - $start_at - $lines_to_get; $i--){
    $content->seek($i);
    $data = $content->current();
    if(empty($data)){
        continue;
    }
}

But this is incredibly slow (around 7 Secs for a 16mb file). If I do it in the normal order it’s instant.

Do anyone knows any method? or what I’m trying to do is crazy? xD I’m just a designer forced to code, so I am not very familiarized with pointers and stuff like that.

Answer 1

In case anybody encounters this problem in the future I came up with a quite simple solution:

//get to the last position of the file and get the pointer position.
$content->seek($content->getSize());
$lines_total = $content->key();
$byte = $content->ftell();

//all the line in the php error log starts like: [21-Feb-2013 22:34:53 UTC] so...
$pattern = '/^\[.*\]/';

for(...){
//get the current output to preg_match it
    $data = $content->current();

//go backward each time it doesnt match a line's start
    while ( preg_match( $pattern, $data ) === 0 ){
    $byte--;
    $content->fseek($byte);
    $data = $content->current();
    }

//go backward 1 more position to start the next loop
    $byte--;
    $content->fseek($byte);
}

Hope this helps someone someday xD