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/**
* 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
* https://gist.github.com/lorenzos/1711e81a9162320fde20
* @license http://creativecommons.org/licenses/by/3.0/
*/
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 -= 1;
// Start reading
$output = '';
$chunk = '';
// While we would like more
while (ftell($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);
}
