class.tar.php

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<?php
// $Id$

class tar
{
    public $filename;
    public $isGzipped;
    public $tar_file;
    public $files;
    public $directories;
    public $numFiles;
    public $numDirectories;

    private function __computeUnsignedChecksum($bytestring)
    {
        $unsigned_chksum = '';
        for ($i = 0; $i < 512; ++$i) {
            $unsigned_chksum += ord($bytestring[$i]);
        }
        for ($i = 0; $i < 8; ++$i) {
            $unsigned_chksum -= ord($bytestring[148 + $i]);
            $unsigned_chksum += ord(' ') * 8;
        }
        return $unsigned_chksum;
    }

    private function __parseNullPaddedString($string)
    {
        $position = strpos($string, chr(0));
        return substr($string, 0, $position);
    }

    private function __parseTar()
    {
        // Read Files from archive
        $tar_length = strlen($this->tar_file);
        $main_offset = 0;
        $this->numFiles = 0;
        while ($main_offset < $tar_length) {
            // If we read a block of 512 nulls, we are at the end of the archive
            if (substr($this->tar_file, $main_offset, 512) == str_repeat(chr(0), 512)) {
                break;
            }
            // Parse file name
            $file_name = $this->__parseNullPaddedString(substr($this->tar_file, $main_offset, 100));
            // Parse the file mode
            $file_mode = substr($this->tar_file, $main_offset + 100, 8);
            // Parse the file user ID
            $file_uid = octdec(substr($this->tar_file, $main_offset + 108, 8));
            // Parse the file group ID
            $file_gid = octdec(substr($this->tar_file, $main_offset + 116, 8));
            // Parse the file size
            $file_size = octdec(substr($this->tar_file, $main_offset + 124, 12));
            // Parse the file update time - unix timestamp format
            $file_time = octdec(substr($this->tar_file, $main_offset + 136, 12));
            // Parse Checksum
            $file_chksum = octdec(substr($this->tar_file, $main_offset + 148, 6));
            // Parse user name
            $file_uname = $this->__parseNullPaddedString(substr($this->tar_file, $main_offset + 265, 32));
            // Parse Group name
            $file_gname = $this->__parseNullPaddedString(substr($this->tar_file, $main_offset + 297, 32));
            // Make sure our file is valid
            if ($this->__computeUnsignedChecksum(substr($this->tar_file, $main_offset, 512)) != $file_chksum) {
                return false;
            }
            // Parse File Contents
            $file_contents = substr($this->tar_file, $main_offset + 512, $file_size);

            if ($file_size > 0) {
                // Increment number of files
                $this->numFiles++;
                // Create us a new file in our array
                $activeFile =& $this->files[];
                // Asign Values
                $activeFile["name"] = $file_name;
                $activeFile["mode"] = $file_mode;
                $activeFile["size"] = $file_size;
                $activeFile["time"] = $file_time;
                $activeFile["user_id"] = $file_uid;
                $activeFile["group_id"] = $file_gid;
                $activeFile["user_name"] = $file_uname;
                $activeFile["group_name"] = $file_gname;
                $activeFile["checksum"] = $file_chksum;
                $activeFile["file"] = $file_contents;
            } else {
                // Increment number of directories
                $this->numDirectories++;
                // Create a new directory in our array
                $activeDir =& $this->directories[];
                // Assign values
                $activeDir["name"] = $file_name;
                $activeDir["mode"] = $file_mode;
                $activeDir["time"] = $file_time;
                $activeDir["user_id"] = $file_uid;
                $activeDir["group_id"] = $file_gid;
                $activeDir["user_name"] = $file_uname;
                $activeDir["group_name"] = $file_gname;
                $activeDir["checksum"] = $file_chksum;
            }
            // Move our offset the number of blocks we have processed
            $main_offset += 512 + (ceil($file_size / 512) * 512);
        }

        return true;
    }

    private function __readTar($filename = '')
    {
        // Set the filename to load
        if (!$filename) {
            $filename = $this->filename;
        }
        // Read in the TAR file
        $fp = fopen($filename, 'rb');
        $this->tar_file = fread($fp, filesize($filename));
        fclose($fp);

        if ($this->tar_file[0] == chr(31) && $this->tar_file[1] == chr(139) && $this->tar_file[2] == chr(8)) {
            if (!function_exists('gzinflate')) {
                return false;
            }
            $this->isGzipped = true;
            $this->tar_file = gzinflate(substr($this->tar_file, 10, -4));
        }
        // Parse the TAR file
        $this->__parseTar();

        return true;
    }

    private function __generateTAR()
    {
        // Clear any data currently in $this->tar_file
        unset($this->tar_file);
        // Generate Records for each directory, if we have directories
        if ($this->numDirectories > 0) {
            foreach ($this->directories as $key => $information) {
                $header = '';
                // Generate tar header for this directory
                // Filename, Permissions, UID, GID, size, Time, checksum, typeflag, linkname, magic, version, user name, group name, devmajor, devminor, prefix, end
                $header .= str_pad($information["name"], 100, chr(0));
                $header .= str_pad(decoct($information["mode"]), 7, "0", STR_PAD_LEFT) . chr(0);
                $header .= str_pad(decoct($information["user_id"]), 7, "0", STR_PAD_LEFT) . chr(0);
                $header .= str_pad(decoct($information["group_id"]), 7, "0", STR_PAD_LEFT) . chr(0);
                $header .= str_pad(decoct(0), 11, "0", STR_PAD_LEFT) . chr(0);
                $header .= str_pad(decoct($information["time"]), 11, "0", STR_PAD_LEFT) . chr(0);
                $header .= str_repeat(" ", 8);
                $header .= "5";
                $header .= str_repeat(chr(0), 100);
                $header .= str_pad("ustar", 6, chr(32));
                $header .= chr(32) . chr(0);
                $header .= str_pad("", 32, chr(0));
                $header .= str_pad("", 32, chr(0));
                $header .= str_repeat(chr(0), 8);
                $header .= str_repeat(chr(0), 8);
                $header .= str_repeat(chr(0), 155);
                $header .= str_repeat(chr(0), 12);
                // Compute header checksum
                $checksum = str_pad(decoct($this->__computeUnsignedChecksum($header)), 6, "0", STR_PAD_LEFT);
                for ($i = 0; $i < 6; ++$i) {
                    $header[(148 + $i)] = substr($checksum, $i, 1);
                }
                $header[154] = chr(0);
                $header[155] = chr(32);
                // Add new tar formatted data to tar file contents
                $this->tar_file .= $header;
            }
        }
        // Generate Records for each file, if we have files (We should...)
        if ($this->numFiles > 0) {
            $this->tar_file = '';
            foreach ($this->files as $key => $information) {
                $header = '';
                // Generate the TAR header for this file
                // Filename, Permissions, UID, GID, size, Time, checksum, typeflag, linkname, magic, version, user name, group name, devmajor, devminor, prefix, end
                $header .= str_pad($information["name"], 100, chr(0));
                $header .= str_pad(decoct($information["mode"]), 7, "0", STR_PAD_LEFT) . chr(0);
                $header .= str_pad(decoct($information["user_id"]), 7, "0", STR_PAD_LEFT) . chr(0);
                $header .= str_pad(decoct($information["group_id"]), 7, "0", STR_PAD_LEFT) . chr(0);
                $header .= str_pad(decoct($information["size"]), 11, "0", STR_PAD_LEFT) . chr(0);
                $header .= str_pad(decoct($information["time"]), 11, "0", STR_PAD_LEFT) . chr(0);
                $header .= str_repeat(" ", 8);
                $header .= "0";
                $header .= str_repeat(chr(0), 100);
                $header .= str_pad("ustar", 6, chr(32));
                $header .= chr(32) . chr(0);
                $header .= str_pad($information["user_name"], 32, chr(0)); // How do I get a file's user name from PHP?
                $header .= str_pad($information["group_name"], 32, chr(0)); // How do I get a file's group name from PHP?
                $header .= str_repeat(chr(0), 8);
                $header .= str_repeat(chr(0), 8);
                $header .= str_repeat(chr(0), 155);
                $header .= str_repeat(chr(0), 12);
                // Compute header checksum
                $checksum = str_pad(decoct($this->__computeUnsignedChecksum($header)), 6, "0", STR_PAD_LEFT);
                for ($i = 0; $i < 6; ++$i) {
                    $header[(148 + $i)] = substr($checksum, $i, 1);
                }
                $header[154] = chr(0);
                $header[155] = chr(32);
                // Pad file contents to byte count divisible by 512
                $file_contents = str_pad($information["file"], (ceil($information["size"] / 512) * 512), chr(0));
                // Add new tar formatted data to tar file contents
                $this->tar_file .= $header . $file_contents;
            }
        }
        // Add 512 bytes of NULLs to designate EOF
        $this->tar_file .= str_repeat(chr(0), 512);
        return true;
    }

    public function openTAR($filename)
    {
        // Clear any values from previous tar archives
        unset($this->filename);
        unset($this->isGzipped);
        unset($this->tar_file);
        unset($this->files);
        unset($this->directories);
        unset($this->numFiles);
        unset($this->numDirectories);
        // If the tar file doesn't exist...
        if (!XoopsLoad::fileExists($filename)) {
            return false;
        }

        $this->filename = $filename;
        // Parse this file
        $this->__readTar();
        return true;
    }

    public function appendTar($filename)
    {
        // If the tar file doesn't exist...
        if (!XoopsLoad::fileExists($filename)) {
            return false;
        }
        $this->__readTar($filename);
        return true;
    }

    public function getFile($filename)
    {
        if ($this->numFiles > 0) {
            foreach ($this->files as $information) {
                if ($information['name'] == $filename) {
                    return $information;
                }
            }
        }
        return false;
    }

    public function getDirectory($dirname)
    {
        if ($this->numDirectories > 0) {
            foreach ($this->directories as $information) {
                if ($information['name'] == $dirname) {
                    return $information;
                }
            }
        }
        return false;
    }

    public function containsFile($filename)
    {
        if ($this->numFiles > 0) {
            foreach ($this->files as $information) {
                if ($information['name'] == $filename) {
                    return true;
                }
            }
        }
        return false;
    }

    public function containsDirectory($dirname)
    {
        if ($this->numDirectories > 0) {
            foreach ($this->directories as $information) {
                if ($information['name'] == $dirname) {
                    return true;
                }
            }
        }
        return false;
    }

    public function addDirectory($dirname)
    {
        if (!XoopsLoad::fileExists($dirname)) {
            return false;
        }
        // Get directory information
        $file_information = stat($dirname);
        // Add directory to processed data
        $this->numDirectories++;
        $activeDir =& $this->directories[];
        $activeDir['name'] = $dirname;
        $activeDir['mode'] = $file_information['mode'];
        $activeDir['time'] = $file_information['time'];
        $activeDir['user_id'] = $file_information['uid'];
        $activeDir['group_id'] = $file_information['gid'];
        $activeDir['checksum'] = isset($checksum) ? $checksum : '';

        return true;
    }

    public function addFile($filename, $binary = false)
    {
        // Make sure the file we are adding exists!
        if (!XoopsLoad::fileExists($filename)) {
            return false;
        }
        // Make sure there are no other files in the archive that have this same filename
        if ($this->containsFile($filename)) {
            return false;
        }
        // Get file information
        $file_information = stat($filename);
        // Read in the file's contents
        if (!$binary) {
            $fp = fopen($filename, 'r');
        } else {
            $fp = fopen($filename, 'rb');
        }
        $file_contents = fread($fp, filesize($filename));
        fclose($fp);
        // Add file to processed data
        $this->numFiles++;
        $activeFile =& $this->files[];
        $activeFile['name'] = $filename;
        $activeFile['mode'] = $file_information['mode'];
        $activeFile['user_id'] = $file_information['uid'];
        $activeFile['group_id'] = $file_information['gid'];
        $activeFile['size'] = $file_information['size'];
        $activeFile['time'] = $file_information['mtime'];
        $activeFile['checksum'] = isset($checksum) ? $checksum : '';
        $activeFile['user_name'] = '';
        $activeFile['group_name'] = '';
        $activeFile['file'] = trim($file_contents);
        return true;
    }

    public function removeFile($filename)
    {
        if ($this->numFiles > 0) {
            foreach ($this->files as $key => $information) {
                if ($information['name'] == $filename) {
                    $this->numFiles--;
                    unset($this->files[$key]);
                    return true;
                }
            }
        }
        return false;
    }

    public function removeDirectory($dirname)
    {
        if ($this->numDirectories > 0) {
            foreach ($this->directories as $key => $information) {
                if ($information['name'] == $dirname) {
                    $this->numDirectories--;
                    unset($this->directories[$key]);
                    return true;
                }
            }
        }
        return false;
    }

    public function saveTar()
    {
        if (!$this->filename) {
            return false;
        }
        // Write tar to current file using specified gzip compression
        $this->toTar($this->filename, $this->isGzipped);
        return true;
    }

    public function toTar($filename, $useGzip)
    {
        if (!$filename) {
            return false;
        }
        // Encode processed files into TAR file format
        $this->__generateTar();
        // GZ Compress the data if we need to
        if ($useGzip) {
            // Make sure we have gzip support
            if (!function_exists('gzencode')) {
                return false;
            }
            $file = gzencode($this->tar_file);
        } else {
            $file = $this->tar_file;
        }
        // Write the TAR file
        $fp = fopen($filename, 'wb');
        fwrite($fp, $file);
        fclose($fp);
        return true;
    }

    public function toTarOutput($filename, $useGzip)
    {
        if (!$filename) {
            return false;
        }
        // Encode processed files into TAR file format
        $this->__generateTar();
        // GZ Compress the data if we need to
        if ($useGzip) {
            // Make sure we have gzip support
            if (!function_exists('gzencode')) {
                return false;
            }
            $file = gzencode($this->tar_file);
        } else {
            $file = $this->tar_file;
        }
        return $file;
    }
}