shibdib / Dramiel

src/lib/logs.php

<?php
/**
 * Slightly modified version of http://www.geekality.net/2011/05/28/php-tail-tackling-large-files/
 * @author Torleif Berger, Lorenzo Stanco
 * @link http://stackoverflow.com/a/15025877/995958
 * @license http://creativecommons.org/licenses/by/3.0/
 * @param string $filepath
 * @param int $lines
 * @param bool $adaptive
 * @return string
 */
function tailCustom($filepath, $lines = 1, $adaptive = true)
{
    // Open file
    $f = @fopen($filepath, 'rb');
    if ($f === false) {
        return false;
    }
    // Sets buffer size, according to the number of lines to retrieve.
    // This gives a performance boost when reading a few lines from the file.
    if (!$adaptive) {
        $buffer = 4096;
    } else {
        $buffer = ($lines < 2 ? 64 : ($lines < 10 ? 512 : 4096));
    }
    // Jump to last character
    fseek($f, -1, SEEK_END);
    // Read it and adjust line number if necessary
    // (Otherwise the result would be wrong if file doesn't end with a blank line)
    if (fread($f, 1) != "\n") {
        --$lines;
    }

    // Start reading
    $output = '';
    $chunk = '';

$chunk is not used, you could remove the assignment.

    // While we would like more
    while (ftell($f) > 0 && $lines >= 0) {
        // Figure out how far back we should jump
        $seek = min(ftell($f), $buffer);
        // Do the jump (backwards, relative to where we are)
        fseek($f, -$seek, SEEK_CUR);
        // Read a chunk and prepend it to our output
        $output = ($chunk = fread($f, $seek)) . $output;
        // Jump back to where we started reading
        fseek($f, -mb_strlen($chunk, '8bit'), SEEK_CUR);
        // Decrease our line counter
        $lines -= substr_count($chunk, "\n");
    }
    // While we have too many lines
    // (Because of buffer size we might have read too many)
    while ($lines++ < 0) {
        // Find first newline and remove all text before that
        $output = substr($output, strpos($output, "\n") + 1);
    }
    // Close file and return
    fclose($f);
    return trim($output);
}