PHP ftruncate函数代码示例

 function DeleteLyrics3()
 {
     // Initialize getID3 engine
     $getID3 = new getID3();
     $ThisFileInfo = $getID3->analyze($this->filename);
     if (isset($ThisFileInfo['lyrics3']['tag_offset_start']) && isset($ThisFileInfo['lyrics3']['tag_offset_end'])) {
         if (is_readable($this->filename) && is_writable($this->filename) && is_file($this->filename) && ($fp = fopen($this->filename, 'a+b'))) {
             flock($fp, LOCK_EX);
             $oldignoreuserabort = ignore_user_abort(true);
             fseek($fp, $ThisFileInfo['lyrics3']['tag_offset_end'], SEEK_SET);
             $DataAfterLyrics3 = '';
             if ($ThisFileInfo['filesize'] > $ThisFileInfo['lyrics3']['tag_offset_end']) {
                 $DataAfterLyrics3 = fread($fp, $ThisFileInfo['filesize'] - $ThisFileInfo['lyrics3']['tag_offset_end']);
             }
             ftruncate($fp, $ThisFileInfo['lyrics3']['tag_offset_start']);
             if (!empty($DataAfterLyrics3)) {
                 fseek($fp, $ThisFileInfo['lyrics3']['tag_offset_start'], SEEK_SET);
                 fwrite($fp, $DataAfterLyrics3, strlen($DataAfterLyrics3));
             }
             flock($fp, LOCK_UN);
             fclose($fp);
             ignore_user_abort($oldignoreuserabort);
             return true;
         } else {
             $this->errors[] = 'Cannot fopen(' . $this->filename . ', "a+b")';
             return false;
         }
     }
     // no Lyrics3 present
     return true;
 }

 public function writeToLog($text)
 {
     if (empty($text)) {
         return;
     }
     $logFile = $this->logFile;
     $logFileHistory = $this->logFileHistory;
     $oldAbortStatus = ignore_user_abort(true);
     if ($fp = @fopen($logFile, "ab")) {
         if (@flock($fp, LOCK_EX)) {
             $logSize = @filesize($logFile);
             $logSize = intval($logSize);
             if ($logSize > $this->maxLogSize) {
                 $this->logFileHistory = $this->logFile . ".old." . time();
                 $logFileHistory = $this->logFileHistory;
                 @copy($logFile, $logFileHistory);
                 ftruncate($fp, 0);
             }
             @fwrite($fp, $text);
             @fflush($fp);
             @flock($fp, LOCK_UN);
             @fclose($fp);
         }
     }
     ignore_user_abort($oldAbortStatus);
 }

 function SaveSession($session)
 {
     $name = $this->file['name'];
     if (!$this->opened_file) {
         if (!($this->opened_file = fopen($name, 'c+'))) {
             return $this->SetPHPError('could not open the token file ' . $name, $php_error_message);
         }
     }
     if (!flock($this->opened_file, LOCK_EX)) {
         return $this->SetPHPError('could not lock the token file ' . $name . ' for writing', $php_error_message);
     }
     if (fseek($this->opened_file, 0)) {
         return $this->SetPHPError('could not rewind the token file ' . $name . ' for writing', $php_error_message);
     }
     if (!ftruncate($this->opened_file, 0)) {
         return $this->SetPHPError('could not truncate the token file ' . $name . ' for writing', $php_error_message);
     }
     if (!fwrite($this->opened_file, json_encode($session))) {
         return $this->SetPHPError('could not write to the token file ' . $name, $php_error_message);
     }
     if (!fclose($this->opened_file)) {
         return $this->SetPHPError('could not close to the token file ' . $name, $php_error_message);
     }
     $this->opened_file = false;
     return true;
 }

 /**
  * @inheritdoc
  */
 public function lock($class, $waitTime = null)
 {
     if (isset($this->locked[$class])) {
         $this->locked[$class]['count']++;
         return true;
     }
     $lockName = $this->getLockName($class);
     $fp = fopen($lockName, 'w');
     $locked = false;
     if (!$waitTime) {
         flock($fp, LOCK_EX);
         $locked = true;
     } else {
         while ($waitTime > 0) {
             if (flock($fp, LOCK_EX | LOCK_NB)) {
                 $locked = true;
                 break;
             }
             sleep(1);
             $waitTime -= 1;
         }
     }
     if (!$locked) {
         fclose($fp);
         return false;
     }
     ftruncate($fp, 0);
     fwrite($fp, 'Locked at: ' . microtime(true));
     $this->locked[$class] = ['res' => $fp, 'count' => 1];
     return true;
 }

 private function renewCache()
 {
     $mask = empty($this->cacheRealPath) ? 'w+b' : 'r+b';
     $resource = fopen($this->cachePath, $mask);
     $exchangeData = array();
     if (!empty($resource)) {
         $wasLocked = false;
         for ($i = 1; $i <= 10; $i++) {
             $lock = flock($resource, LOCK_EX | LOCK_NB);
             if ($lock) {
                 if ($wasLocked) {
                     $exchangeData = json_decode(fread($resource, filesize($this->cacheRealPath)), true);
                 } else {
                     $newExchangeData = $this->getFromWeb();
                     if (!empty($newExchangeData)) {
                         ftruncate($resource, 0);
                         $jsonData = json_encode($newExchangeData);
                         fwrite($resource, $jsonData);
                         $exchangeData = $newExchangeData;
                         fflush($resource);
                     }
                 }
                 flock($resource, LOCK_UN);
                 break;
             } else {
                 $wasLocked = true;
                 sleep(1);
             }
         }
     }
     fclose($resource);
     return $exchangeData;
 }

 /**
  * Saves data to the cache. Anything that evaluates to FALSE, NULL,
  * '', 0 will not be saved.
  *
  * @param string $key An identifier for the data.
  * @param mixed $data The data to be saved.
  * @param integer $ttl Lifetime of the stored data. In seconds.
  * @returns boolean TRUE on success, FALSE otherwise.
  */
 public static function set($key, $data = false, $ttl = 3600)
 {
     if (!$key) {
         self::$error = "Invalid key";
         return false;
     }
     if (!$data) {
         self::$error = "Invalid data";
         return false;
     }
     $key = self::makeFileKey($key);
     if (!is_integer($ttl)) {
         $ttl = (int) $ttl;
     }
     $store = array('data' => $data, 'ttl' => time() + $ttl);
     $status = false;
     try {
         $fh = fopen($key, "c");
         if (flock($fh, LOCK_EX)) {
             ftruncate($fh, 0);
             fwrite($fh, json_encode($store));
             flock($fh, LOCK_UN);
             $status = true;
         }
         fclose($fh);
     } catch (Exception $e) {
         self::$error = "Exception caught: " . $e->getMessage();
         return false;
     }
     return $status;
 }

 /**
  * Clear entries from chosen file.
  *
  * @param mixed $handle
  */
 public function clear($handle)
 {
     if ($this->open($handle) && is_resource($this->_handles[$handle])) {
         @ftruncate($this->_handles[$handle], 0);
     }
     do_action('learn_press_log_clear', $handle);
 }

 /**
  * Creates a new post by pushing it to the array 
  * of blog posts stored in the local directory.
  * @param newPost - non-null string containing the new post JSON object.
  */
 function CreatePost($newPost)
 {
     $postFileName = $this->postFilename;
     $fileExists = file_exists($postFileName);
     $postFile = $this->createBlogPostFileHandle($postFileName, $fileExists);
     $fileSize = filesize($postFileName);
     // Store some useful variables for blog post parsing.
     $contents;
     $blogPosts = [];
     // Check if file size is larger than 0 or not empty.
     if ($fileSize > 0) {
         // Read the existing blog post file and store in a string.
         $contents = fread($postFile, $fileSize);
         // TODO(Jess): Delete later - for debugging.
         // print($contents);
         // Parse the contents JSON string into an array.
         $blogPosts = json_decode($contents, true) ?: [];
         // print($blogPosts);
         // Clear the blog post file.
         ftruncate($postFile, 0);
         // Update the pointer back to the beginning of the file.
         fseek($postFile, 0);
     }
     // Push the new blog post to the array of blog posts.
     array_push($blogPosts, $newPost);
     // Encode and store back into a JSON string.
     $postJSONString = json_encode($blogPosts);
     // Update the post file to the new JSON string.
     fwrite($postFile, $postJSONString);
     fclose($postFile);
     // TODO(Jess): Delete later - for debugging.
     print $postJSONString;
 }

function write_cache_file($file, $content)
{
    // Open
    $handle = @fopen($file, 'r+b');
    // @ - file may not exist
    if (!$handle) {
        $handle = fopen($file, 'wb');
        if (!$handle) {
            return false;
        }
    }
    // Lock
    flock($handle, LOCK_EX);
    ftruncate($handle, 0);
    // Write
    if (fwrite($handle, $content) === false) {
        // Unlock and close
        flock($handle, LOCK_UN);
        fclose($handle);
        return false;
    }
    // Unlock and close
    flock($handle, LOCK_UN);
    fclose($handle);
    return true;
}

 protected static function unban_callback($handle, $parameters)
 {
     $size = $parameters['initial_file_size'];
     if (0 === $size) {
         return true;
     }
     $contents = fread($handle, $size);
     if (empty($contents)) {
         return;
     }
     $now = time();
     $ban_lines = explode("\n", $contents);
     $new_bans = array();
     // Unban expired bans
     foreach ($ban_lines as $ban_line) {
         if (empty($ban_line)) {
             continue;
         }
         list($ip, $expires) = explode(' ', $ban_line);
         if (!empty($parameters['ip']) && $parameters['ip'] === $ip) {
             continue;
         }
         if (!empty($expires) && (int) $expires > $now) {
             $new_bans[] = $ban_line;
         }
     }
     $new_ban_lines = implode("\n", $new_bans);
     if (!empty($new_ban_lines)) {
         $new_ban_lines .= "\n";
     }
     // Replace .htaccess contents
     ftruncate($handle, 0);
     rewind($handle);
     return fwrite($handle, $new_ban_lines);
 }

function getSequence($name, $folder = '/tmp', $default = 0)
{
    // Build a filename from the folder and sequence name
    $filename = realpath($folder) . '/' . $name . '.seq';
    // Open the file
    $fp = fopen($filename, "a+");
    // Lock the file so no other processes can use it
    if (flock($fp, LOCK_EX)) {
        // Fetch the current number from the file
        $num = trim(stream_get_contents($fp));
        // Check that what we read from the file was a number
        if (!ctype_digit($num)) {
            // If its not a number, lets reset to the default value
            $newnum = $default;
        } else {
            // If its a number, increment it
            $newnum = $num + 1;
        }
        // Delete the contents of the file
        ftruncate($fp, 0);
        rewind($fp);
        // Write the new number to the file
        fwrite($fp, "{$newnum}\n");
        // Release the lock
        flock($fp, LOCK_UN);
    } else {
        echo "Couldn't get the lock!";
    }
    // Close the file
    fclose($fp);
    // Return the incremented number
    return $newnum;
}

/**
 * 写文件
 *
 * @return intager 写入数据的字节数
 */
function hg_file_write($filename, $content, $mode = 'rb+')
{
    $length = strlen($content);
    @touch($filename);
    if (!is_writeable($filename)) {
        @chmod($filename, 0666);
    }
    if (($fp = fopen($filename, $mode)) === false) {
        trigger_error('hg_file_write() failed to open stream: Permission denied', E_USER_WARNING);
        return false;
    }
    flock($fp, LOCK_EX | LOCK_NB);
    $bytes = 0;
    if (($bytes = @fwrite($fp, $content)) === false) {
        $errormsg = sprintf('file_write() Failed to write %d bytes to %s', $length, $filename);
        trigger_error($errormsg, E_USER_WARNING);
        return false;
    }
    if ($mode == 'rb+') {
        @ftruncate($fp, $length);
    }
    @fclose($fp);
    // 检查是否写入了所有的数据
    if ($bytes != $length) {
        $errormsg = sprintf('file_write() Only %d of %d bytes written, possibly out of free disk space.', $bytes, $length);
        trigger_error($errormsg, E_USER_WARNING);
        return false;
    }
    // 返回长度
    return $bytes;
}

 /**
  * Creates or overwrites a new JPA archive
  *
  * @param $archive The full path to the JPA archive
  *
  * @return bool True on success
  */
 public function create($archive)
 {
     $this->dataFileName = $archive;
     // Try to kill the archive if it exists
     $fp = @fopen($this->dataFileName, "wb");
     if (!($fp === false)) {
         @ftruncate($fp, 0);
         @fclose($fp);
     } else {
         if (file_exists($this->dataFileName)) {
             @unlink($this->dataFileName);
         }
         @touch($this->dataFileName);
     }
     if (!is_writable($archive)) {
         $this->error = 'Can\'t open ' . $archive . ' for writing';
         return false;
     }
     // Write the initial instance of the archive header
     $this->writeArchiveHeader();
     if (!empty($error)) {
         return false;
     }
     return true;
 }

 function RemoveID3v1()
 {
     if ($ThisFileInfo['filesize'] >= pow(2, 31)) {
         $this->errors[] = 'Unable to write ID3v1 because file is larger than 2GB';
         return false;
     }
     // File MUST be writeable - CHMOD(646) at least
     if (is_writeable($this->filename)) {
         if ($fp_source = @fopen($this->filename, 'r+b')) {
             fseek($fp_source, -128, SEEK_END);
             if (fread($fp_source, 3) == 'TAG') {
                 ftruncate($fp_source, filesize($this->filename) - 128);
             } else {
                 // no ID3v1 tag to begin with - do nothing
             }
             fclose($fp_source);
             return true;
         } else {
             $this->errors[] = 'Could not open ' . $this->filename . ' mode "r+b"';
         }
     } else {
         $this->errors[] = $this->filename . ' is not writeable';
     }
     return false;
 }

function write_config_file($filename, $comments) {
	global $config_template;

	$tokens = array('{USER}',
					'{PASSWORD}',
					'{HOST}',
					'{PORT}',
					'{DBNAME}',
					'{TABLE_PREFIX}',
					'{HEADER_IMG}',
					'{HEADER_LOGO}',
					'{GENERATED_COMMENTS}',
					'{CONTENT_DIR}',
					'{MAIL_USE_SMTP}',
					'{GET_FILE}'
				);

	if ($_POST['step1']['old_path'] != '') {
		$values = array(urldecode($_POST['step1']['db_login']),
					addslashes(urldecode($_POST['step1']['db_password'])),
					$_POST['step1']['db_host'],
					$_POST['step1']['db_port'],
					$_POST['step1']['db_name'],
					$_POST['step1']['tb_prefix'],
					addslashes(urldecode($_POST['step1']['header_img'])),
					addslashes(urldecode($_POST['step1']['header_logo'])),
					$comments,
					addslashes(urldecode($_POST['step5']['content_dir'])),
					$_POST['step1']['smtp'],
					$_POST['step1']['get_file']
				);
	} else {
		$values = array(urldecode($_POST['step2']['db_login']),
					addslashes(urldecode($_POST['step2']['db_password'])),
					$_POST['step2']['db_host'],
					$_POST['step2']['db_port'],
					$_POST['step2']['db_name'],
					$_POST['step2']['tb_prefix'],
					'', //header image
					'', //header logo
					$comments,
					addslashes(urldecode($_POST['step4']['content_dir'])),
					$_POST['step3']['smtp'],
					$_POST['step4']['get_file']
				);
	}

	$config_template = str_replace($tokens, $values, $config_template);

	if (!$handle = @fopen($filename, 'wb')) {
         return false;
    }
	@ftruncate($handle,0);
    if (!@fwrite($handle, $config_template, strlen($config_template))) {
		return false;
    }
        
    @fclose($handle);
	return true;
}