1
|
|
|
<?php |
2
|
|
|
/** |
3
|
|
|
* Slightly modified version of http://www.geekality.net/2011/05/28/php-tail-tackling-large-files/ |
4
|
|
|
* @author Torleif Berger, Lorenzo Stanco |
5
|
|
|
* @link http://stackoverflow.com/a/15025877/995958 |
6
|
|
|
* @license http://creativecommons.org/licenses/by/3.0/ |
7
|
|
|
* @param string $filepath |
8
|
|
|
* @param int $lines |
9
|
|
|
* @param bool $adaptive |
10
|
|
|
* @return string |
11
|
|
|
*/ |
12
|
|
|
function tailCustom($filepath, $lines = 1, $adaptive = true) |
13
|
|
|
{ |
14
|
|
|
// Open file |
15
|
|
|
$f = @fopen($filepath, 'rb'); |
16
|
|
|
if ($f === false) { |
17
|
|
|
return false; |
18
|
|
|
} |
19
|
|
|
// Sets buffer size, according to the number of lines to retrieve. |
20
|
|
|
// This gives a performance boost when reading a few lines from the file. |
21
|
|
|
if (!$adaptive) { |
22
|
|
|
$buffer = 4096; |
23
|
|
|
} else { |
24
|
|
|
$buffer = ($lines < 2 ? 64 : ($lines < 10 ? 512 : 4096)); |
25
|
|
|
} |
26
|
|
|
// Jump to last character |
27
|
|
|
fseek($f, -1, SEEK_END); |
28
|
|
|
// Read it and adjust line number if necessary |
29
|
|
|
// (Otherwise the result would be wrong if file doesn't end with a blank line) |
30
|
|
|
if (fread($f, 1) != "\n") { |
31
|
|
|
--$lines; |
32
|
|
|
} |
33
|
|
|
|
34
|
|
|
// Start reading |
35
|
|
|
$output = ''; |
36
|
|
|
$chunk = ''; |
|
|
|
|
37
|
|
|
// While we would like more |
38
|
|
|
while (ftell($f) > 0 && $lines >= 0) { |
39
|
|
|
// Figure out how far back we should jump |
40
|
|
|
$seek = min(ftell($f), $buffer); |
41
|
|
|
// Do the jump (backwards, relative to where we are) |
42
|
|
|
fseek($f, -$seek, SEEK_CUR); |
43
|
|
|
// Read a chunk and prepend it to our output |
44
|
|
|
$output = ($chunk = fread($f, $seek)) . $output; |
45
|
|
|
// Jump back to where we started reading |
46
|
|
|
fseek($f, -mb_strlen($chunk, '8bit'), SEEK_CUR); |
47
|
|
|
// Decrease our line counter |
48
|
|
|
$lines -= substr_count($chunk, "\n"); |
49
|
|
|
} |
50
|
|
|
// While we have too many lines |
51
|
|
|
// (Because of buffer size we might have read too many) |
52
|
|
|
while ($lines++ < 0) { |
53
|
|
|
// Find first newline and remove all text before that |
54
|
|
|
$output = substr($output, strpos($output, "\n") + 1); |
55
|
|
|
} |
56
|
|
|
// Close file and return |
57
|
|
|
fclose($f); |
58
|
|
|
return trim($output); |
59
|
|
|
} |
60
|
|
|
|
This check looks for variable assignements that are either overwritten by other assignments or where the variable is not used subsequently.
Both the
$myVar
assignment in line 1 and the$higher
assignment in line 2 are dead. The first because$myVar
is never used and the second because$higher
is always overwritten for every possible time line.