ter = array_value($config, 'filter'); $arr = array_value($filter, $type); $enable = array_value($arr, 'enable'); $wordarr = array_value($arr, 'keyword'); if (0 == $enable || empty($wordarr)) return FALSE; foreach ($wordarr as $_keyword) { if (!$_keyword) continue; $r = strpos(strtolower($keyword), strtolower($_keyword)); if (FALSE !== $r) { $error = $_keyword; return TRUE; } } return FALSE; } // return http://domain.com OR https://domain.com function url_prefix() { $http = ((isset($_SERVER['HTTPS']) && 'on' == $_SERVER['HTTPS']) || (isset($_SERVER['HTTP_X_FORWARDED_PROTO']) && $_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https')) ? 'https://' : 'http://'; return $http . $_SERVER['HTTP_HOST']; } // 唯一身份ID function uniq_id() { return uniqid(substr(md5(microtime(true) . mt_rand(1000, 9999)), 8, 8)); } // 生成订单号 14位 function trade_no() { $trade_no = str_replace('.', '', microtime(1)); $strlen = mb_strlen($trade_no, 'UTF-8'); $strlen = 14 - $strlen; $str = ''; if ($strlen) { for ($i = 0; $i <= $strlen; $i++) { if ($i < $strlen) $str .= '0'; } } return $trade_no . $str; } // 生成订单号 16位 function trade_no_16() { $explode = explode(' ', microtime()); $trade_no = $explode[1] . mb_substr($explode[0], 2, 6, 'UTF-8'); return $trade_no; } // 当前年的天数 function date_year($time = NULL) { $time = intval($time) ? $time : time(); return date('L', $time) + 365; } // 当前年份中的第几天 function date_z($time = NULL) { $time = intval($time) ? $time : time(); return date('z', $time); } // 当前月份中的第几天，没有前导零 1 到 31 function date_j($time = NULL) { $time = intval($time) ? $time : time(); return date('j', $time); } // 当前月份中的第几天，有前导零的2位数字 01 到 31 function date_d($time = NULL) { $time = intval($time) ? $time : time(); return date('d', $time); } // 当前时间为星期中的第几天 数字表示 1表示星期一 到 7表示星期天 function date_w_n($time = NULL) { $time = intval($time) ? $time : time(); return date('N', $time); } // 当前日第几周 function date_d_w($time = NULL) { $time = intval($time) ? $time : time(); return date('W', $time); } // 当前几月 没有前导零1-12 function date_n($time = NULL) { $time = intval($time) ? $time : time(); return date('n', $time); } // 当前月的天数 function date_t($time = NULL) { $time = intval($time) ? $time : time(); return date('t', $time); } // 0 o'clock on the day function clock_zero() { return strtotime(date('Ymd')); } // 24 o'clock on the day function clock_twenty_four() { return strtotime(date('Ymd')) + 86400; } // 8点过期 / expired at 8 a.m. function eight_expired($time = NULL) { $time = intval($time) ? $time : time(); // 当前时间大于8点则改为第二天8点过期 $life = date('G') <= 8 ? (strtotime(date('Ymd')) + 28800 - $time) : clock_twenty_four() - $time + 28800; return $life; } // 24点过期 / expired at 24 a.m. function twenty_four_expired($time = NULL) { $time = intval($time) ? $time : time(); $twenty_four = clock_twenty_four(); $life = $twenty_four - $time; return $life; } /** * @param $url 提交地址 * @param string $post POST数组 / 空为GET获取数据 / $post='GET'获取连续跳转最终URL * @param string $cookie cookie * @param int $timeout 超时 * @param int $ms 设为1是毫秒 * @return mixed 返回数据 */ function https_request($url, $post = '', $cookie = '', $timeout = 30, $ms = 0) { if (empty($url)) return FALSE; if (version_compare(PHP_VERSION, '5.2.3', '<')) { $ms = 0; $timeout = 30; } is_array($post) and $post = http_build_query($post); // 没有安装curl 使用http的形式，支持post if (!extension_loaded('curl')) { //throw new Exception('server not install CURL'); if ($post) { return https_post($url, $post, $cookie, $timeout); } else { return http_get($url, $cookie, $timeout); } } is_array($cookie) and $cookie = http_build_query($cookie); $curl = curl_init(); // 返回执行结果，不输出 curl_setopt($curl, CURLOPT_RETURNTRANSFER, true); //php5.5跟php5.6中的CURLOPT_SAFE_UPLOAD的默认值不同 if (class_exists('\CURLFile')) { curl_setopt($curl, CURLOPT_SAFE_UPLOAD, true); } else { defined('CURLOPT_SAFE_UPLOAD') and curl_setopt($curl, CURLOPT_SAFE_UPLOAD, false); } // 设定请求的RUL curl_setopt($curl, CURLOPT_URL, $url); // 设定返回信息中包含响应信息头 if (ini_get('safe_mode') && ini_get('open_basedir')) { // $post参数必须为GET if ('GET' == $post) { // 安全模式时将头文件的信息作为数据流输出 curl_setopt($curl, CURLOPT_HEADER, true); // 安全模式采用连续抓取 curl_setopt($curl, CURLOPT_NOBODY, true); } } else { curl_setopt($curl, CURLOPT_HEADER, false); // 允许跳转10次 curl_setopt($curl, CURLOPT_MAXREDIRS, 10); // 使用自动跳转，返回最后的Location curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true); } $ua1 = 'Mozilla/5.0 (iPhone; CPU iPhone OS 13_2_3 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.0.3 Mobile/15E148 Safari/604.1'; $ua = empty($_SERVER["HTTP_USER_AGENT"]) ? $ua1 : $_SERVER["HTTP_USER_AGENT"]; curl_setopt($curl, CURLOPT_USERAGENT, $ua); // 兼容HTTPS if (FALSE !== stripos($url, 'https://')) { curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, FALSE); curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, FALSE); //ssl版本控制 //curl_setopt($curl, CURLOPT_SSLVERSION, CURL_SSLVERSION_TLSv1); curl_setopt($curl, CURLOPT_SSLVERSION, true); } $header = array('Content-type: application/x-www-form-urlencoded;charset=UTF-8', 'X-Requested-With: XMLHttpRequest'); $cookie and $header[] = "Cookie: $cookie"; curl_setopt($curl, CURLOPT_HTTPHEADER, $header); if ($post) { // POST curl_setopt($curl, CURLOPT_POST, true); // 自动设置Referer curl_setopt($curl, CURLOPT_AUTOREFERER, true); curl_setopt($curl, CURLOPT_POSTFIELDS, $post); } if ($ms) { curl_setopt($curl, CURLOPT_NOSIGNAL, true); // 设置毫秒超时 curl_setopt($curl, CURLOPT_TIMEOUT_MS, intval($timeout)); // 超时毫秒 } else { curl_setopt($curl, CURLOPT_TIMEOUT, intval($timeout)); // 秒超时 } //优先解析 IPv6 超时后IPv4 //curl_setopt($curl, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V4); curl_setopt($curl, CURLOPT_ENCODING, 'gzip'); // 返回执行结果 $output = curl_exec($curl); // 有效URL，输出URL非URL页面内容 CURLOPT_RETURNTRANSFER 必须为false 'GET' == $post and $output = curl_getinfo($curl, CURLINFO_EFFECTIVE_URL); curl_close($curl); return $output; } function save_image($img) { $ch = curl_init(); // 设定请求的RUL curl_setopt($ch, CURLOPT_URL, $img); // 设定返回信息中包含响应信息头 启用时会将头文件的信息作为数据流输出 //curl_setopt($ch, CURLOPT_HEADER, false); //curl_setopt($ch, CURLOPT_USERAGENT, $_SERVER["HTTP_USER_AGENT"]); // true表示$html,false表示echo $html curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 10); curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false); curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); //curl_setopt($ch, CURLOPT_BINARYTRANSFER, 1); //curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 0); curl_setopt($ch, CURLOPT_ENCODING, 'gzip'); $output = curl_exec($ch); curl_close($ch); return $output; } // 计算字串宽度:剧中对齐(字体大小/字串内容/字体链接/背景宽度/倍数) function calculate_str_width($size, $str, $font, $width, $multiple = 2) { $box = imagettfbbox($size, 0, $font, $str); return ($width - $box[4] - $box[6]) / $multiple; } // 搜索目录下的文件 比对文件后缀 function search_directory($path) { if (is_dir($path)) { $paths = scandir($path); foreach ($paths as $val) { $sub_path = $path . '/' . $val; if ('.' == $val || '..' == $val) { continue; } else if (is_dir($sub_path)) { //echo '目录名:' . $val . '
'; search_directory($sub_path); } else { //echo ' 最底层文件: ' . $path . '/' . $val . '
'; $ext = strtolower(file_ext($sub_path)); if (in_array($ext, array('php', 'asp', 'jsp', 'cgi', 'exe', 'dll'), TRUE)) { echo '异常文件：' . $sub_path . '
'; } } } } } // 一维数组转字符串 $sign待签名字符串 $url为urlencode转码GET参数字符串 function array_to_string($arr, &$sign = '', &$url = '') { if (count($arr) != count($arr, 1)) throw new Exception('Does not support multi-dimensional array to string'); // 注销签名 unset($arr['sign']); // 排序 ksort($arr); reset($arr); // 转字符串做签名 $url = ''; $sign = ''; foreach ($arr as $key => $val) { if (empty($val) || is_array($val)) continue; $url .= $key . '=' . urlencode($val) . '&'; $sign .= $key . '=' . $val . '&'; } $url = substr($url, 0, -1); $url = htmlspecialchars($url); $sign = substr($sign, 0, -1); } // 私钥生成签名 function rsa_create_sign($data, $key, $sign_type = 'RSA') { if (!function_exists('openssl_sign')) throw new Exception('OpenSSL extension is not enabled'); if (!defined('OPENSSL_ALGO_SHA256')) throw new Exception('Only versions above PHP 5.4.8 support SHA256'); $key = wordwrap($key, 64, "\n", true); if (FALSE === $key) throw new Exception('Private Key Error'); $key = "-----BEGIN RSA PRIVATE KEY-----\n$key\n-----END RSA PRIVATE KEY-----"; if ('RSA2' == $sign_type) { openssl_sign($data, $sign, $key, OPENSSL_ALGO_SHA256); } else { openssl_sign($data, $sign, $key, OPENSSL_ALGO_SHA1); } // 加密 return base64_encode($sign); } // 公钥验证签名 function rsa_verify_sign($data, $sign, $key, $sign_type = 'RSA') { $key = wordwrap($key, 64, "\n", true); if (FALSE === $key) throw new Exception('Public Key Error'); $key = "-----BEGIN PUBLIC KEY-----\n$key\n-----END PUBLIC KEY-----"; // 签名正确返回1 签名不正确返回0 错误-1 if ('RSA2' == $sign_type) { $result = openssl_verify($data, base64_decode($sign), $key, OPENSSL_ALGO_SHA256); } else { $result = openssl_verify($data, base64_decode($sign), $key, OPENSSL_ALGO_SHA1); } return $result === 1; } // Array to xml array('appid' => 'appid', 'code' => 'success') function array_to_xml($arr) { if (!is_array($arr) || empty($arr)) throw new Exception('Array Error'); $xml = ""; foreach ($arr as $key => $val) { if (is_numeric($val)) { $xml .= "<" . $key . ">" . $val . ""; } else { $xml .= "<" . $key . ">"; } } $xml .= ""; return $xml; } // Xml to array function xml_to_array($xml) { if (!$xml) throw new Exception('XML error'); $old = libxml_disable_entity_loader(true); // xml解析 $result = (array)simplexml_load_string($xml, null, LIBXML_NOCDATA | LIBXML_COMPACT); // 恢复旧值 if (FALSE === $old) libxml_disable_entity_loader(false); return $result; } // 逐行读取 function well_import($file) { if ($handle = fopen($file, 'r')) { while (!feof($handle)) { yield trim(fgets($handle)); } fclose($handle); } } // 计算总行数 function well_import_total($file, $key = 'well_import_total') { static $cache = array(); if (isset($cache[$key])) return $cache[$key]; $count = cache_get($key); if (NULL === $count) { $count = 0; $globs = well_import($file); while ($globs->valid()) { ++$count; $globs->next(); // 指向下一个 } $count and cache_set($key, $count, 300); } return $cache[$key] = $count; } $g_dir_file = FALSE; function well_search_dir($path) { global $g_dir_file; FALSE === $g_dir_file and $g_dir_file = array(); if (is_dir($path)) { $paths = scandir($path); foreach ($paths as $val) { $sub_path = $path . '/' . $val; if ('.' == $val || '..' == $val) { continue; } else if (is_dir($sub_path)) { well_search_dir($sub_path); } else { $g_dir_file[] = $sub_path; } } } return $g_dir_file; } ?>c++ - Error when repeating forward declaration with default template argument - Stack Overflow

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    c++ - Error when repeating forward declaration with default template argument - Stack Overflow

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    When repeating the declaration of a template class with defaulted argument, I get an error:

    <source>:12:23: error: redefinition of default argument for 'class<template-parameter-1-2>'
   12 | template <typename T, typename = T>
      |                       ^~~~~~~~
<source>:9:23: note: original definition appeared here
    9 | template <typename T, typename = T>
      |

    Repeating a template forward declaration without default arguments doesn't give any errors. Repeating the same one, but without defaulting the argument also works (but IMO it doesn't make sense and should give some error).
    Here's the whole example:

    template <typename T>
struct ok;

template <typename T>
struct ok;

template <typename T, typename = T>
struct not_ok;

template <typename T, typename = T>
struct not_ok;

template <typename T, typename = T>
struct why_is_it_ok;

template <typename T, typename>
struct why_is_it_ok;

    WHY?

    When repeating the declaration of a template class with defaulted argument, I get an error:

    <source>:12:23: error: redefinition of default argument for 'class<template-parameter-1-2>'
   12 | template <typename T, typename = T>
      |                       ^~~~~~~~
<source>:9:23: note: original definition appeared here
    9 | template <typename T, typename = T>
      |

    Repeating a template forward declaration without default arguments doesn't give any errors. Repeating the same one, but without defaulting the argument also works (but IMO it doesn't make sense and should give some error).
    Here's the whole example:

    template <typename T>
struct ok;

template <typename T>
struct ok;

template <typename T, typename = T>
struct not_ok;

template <typename T, typename = T>
struct not_ok;

template <typename T, typename = T>
struct why_is_it_ok;

template <typename T, typename>
struct why_is_it_ok;

    WHY?

    • c++
    • templates
    • forward-declaration
    Share Improve this question asked Mar 31 at 12:36 Sergey KolesnikSergey Kolesnik 3,7272 gold badges14 silver badges44 bronze badges 5
    • to avoid ambiguity (in cases when default type is set to different type). – Marek R Commented Mar 31 at 13:00
    • @MarekR how is it possible to set to a "different" type with the same signature, where the default type is the first one? I'd expect ambiguity when having 2 forward declarations, where only one has a defaulted argument – Sergey Kolesnik Commented Mar 31 at 13:04
    • If you could repeat default type for template parameter, then it would be possible to do template <typename T, typename = int> struct not_ok;. – Marek R Commented Mar 31 at 13:08
    • Also, if you do template <typename T, typename = X> struct not_ok;, there could be a different X visible at different points. In your specific case that is not possible, but there is no exception for the types being the same. You can only give a default value once. – BoP Commented Mar 31 at 13:18
    • 1 That's how default arguments work, template or not. You define each one exactly once per TU. It doesn't matter whether it's a forward declaration or not. You are not allowed to define it twice because then the compiler would have to check whether two mentions are "the same", and before that you would need to define what "the same" means, which is rather non-trivial. Not impossible, but it is much easier to outright disallow it. – n. m. could be an AI Commented Mar 31 at 13:20
    Add a comment  | 

    1 Answer 1

    Reset to default 6

    Just like default parameters for function parameters, default parameters for template parameters are only allowed to be set once per scope.

    template <typename T>
struct ok;

template <typename T>
struct ok;

    Is fine because neither declaration introduces a default parameter.

    template <typename T, typename = T>
struct not_ok;

template <typename T, typename = T>
struct not_ok;

    Is not allowed because the second unnamed parameter is defaulted twice in the same scope.

    template <typename T, typename = T>
struct why_is_it_ok;

template <typename T, typename>
struct why_is_it_ok;

    Is allowed because only the first declaration declares a default parameter

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