PHP: sha1_file

Описание

string sha1_file ( string filename [, bool raw_output] )

Вычисляет SHA1 хэш файла, имя которого задано аргументом filename, используя алгоритм US Secure Hash Algorithm 1 и возвращает этот хэш. Хэш представляет собой 40-значное шестнадцатеричное число. Если необязательный аргумент raw_output имеет значение TRUE, то возвращается двоичная строка из 20 символов.

Замечание: Необязательный аргумент raw_output был добавлен в PHP 5.0.0 и по умолчанию равен FALSE

См. также описание функций sha1(), crc32() и md5_file().

sha1_file

gubatron at gmail dot com
10-Feb-2006 07:02


P2P programs like LimeWire utilize sha1 to identify files. However they do it in base32. Here's an utility class if you want to write a Gnutella client in PHP5



/**

Utility base32 SHA1 class for PHP5

Copyright (C) 2006  Karl Magdsick (original author for Python)

                    Angel Leon (ported to PHP5)

                    Lime Wire LLC



This program is free software; you can redistribute it and/or

modify it under the terms of the GNU General Public License

as published by the Free Software Foundation; either version 2

of the License, or (at your option) any later version.



This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

GNU General Public License for more details.



You should have received a copy of the GNU General Public License

along with this program; if not, write to the Free Software

Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

*/

class SHA1 {

  static $BASE32_ALPHABET = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567';



  /** Given a file it creates a magnetmix */

  static function fileSHA1($file) {

    $raw = sha1_file($file,true);

    return SHA1::base32encode($raw);

  } //fileSHA1



  /** Takes raw input and converts it to base32 */

  static function base32encode($input) {

    $output = '';

    $position = 0;

    $storedData = 0;

    $storedBitCount = 0;

    $index = 0;



    while ($index < strlen($input)) {

      $storedData <<= 8;

      $storedData += ord($input[$index]);

      $storedBitCount += 8;

      $index += 1;



      //take as much data as possible out of storedData

      while ($storedBitCount >= 5) {

        $storedBitCount -= 5;

        $output .= SHA1::$BASE32_ALPHABET[$storedData >> $storedBitCount];

        $storedData &= ((1 << $storedBitCount) - 1);

      }

    } //while



    //deal with leftover data

    if ($storedBitCount > 0) {

      $storedData <<= (5-$storedBitCount);

      $output .= SHA1::$BASE32_ALPHABET[$storedData];

    }



    return $output;

  } //base32encode



}