RarEntry::getCrc() returs a lowercase hex-string (e.g. 'bf6fa85c') the same as hash_... functions, using the same polynomial as 'crc32b' algorithm.
So, it can be used to check CRC after a stream unpacking:
<?php
$archive_name = 'archive.rar';
$entry_name = 'someentry.ext';
$rar = RarArchive::open($archive_name) or die("Cannot open archive $archive_name");
if ($rar->isBroken()) {
die("The archive is broken!");
}
$entry = $rar->getEntry($entry_name) or die("Cannot find entry $entry_name");
$stream = $entry->getStream() or die("Cannot open stream");
$crc = hash_init('crc32b'); // Initializing the hash function
while (!feof($stream)) {
$s = fread($stream, 8192);
if ($s === false) {
// Error reading (do not use fread(...) or die(...), because fread can return '0'!)
die('Error reading the compressed file.');
}
hash_update($crc, $s); // updating the hash
// ...
// Do whatever with the $s
}
fclose($stream);
$got_crc = hash_final($crc);
$need_crc = $entry->getCrc();
print("Got CRC: $got_crc" . PHP_EOL);
print("Need CRC: $need_crc" . PHP_EOL);
if ($got_crc != $need_crc) {
// rollback
print("Sorry guys, the file was incorrect!" . PHP_EOL);
} else {
print("Everything is ok" . PHP_EOL);
}
?>
RarEntry::getCrc
(PECL rar >= 0.1)
RarEntry::getCrc — Get CRC of the entry
Descrierea
public RarEntry::getCrc
(
) : string
Returns an hexadecimal string representation of the CRC of the archive entry.
Parametri
Această funcție nu are parametri.
Valorile întoarse
Returns the CRC of the archive entry or false on error.
Istoricul schimbărilor
| Versiune | Descriere |
|---|---|
| PECL rar 2.0.0 | This method now returns correct values for multiple volume archives. |
add a note
User Contributed Notes 1 note
aterlux at mail dot ru ¶
6 years ago
