file_get_contents解决方案对于大型文件而言效率不高。此解决方案可能需要更长的时间，具体取决于需要添加的数据量（实际上越多越好），但是它不会消耗内存。
<?php$cache_new = "Prepend this"; // this gets prepended$file = "file.dat"; // the file to which $cache_new gets prepended$handle = fopen($file, "r+");$len = strlen($cache_new);$final_len = filesize($file) + $len;$cache_old = fread($handle, $len);rewind($handle);$i = 1;while (ftell($handle) < $final_len) { fwrite($handle, $cache_new); $cache_new = $cache_old; $cache_old = fread($handle, $len); fseek($handle, $i * $len); $i++;}?>
