241 lines
9.3 KiB
JavaScript
241 lines
9.3 KiB
JavaScript
/* codec.js —— 编码/加解密纯前端算法库
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* 提供：UTF-8、Base64、Base32、URL、Unicode、SHA 系列（Web Crypto 原生）
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* MD5 / SHA-224 依赖 CryptoJS（由页面懒加载，双 CDN fallback）
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*/
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(function (global) {
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'use strict';
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/* ---------- UTF-8 工具 ---------- */
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function utf8Encode(str) {
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if (typeof TextEncoder !== 'undefined') return new TextEncoder().encode(str);
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// 降级实现
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var out = [], ch, i, code;
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for (i = 0; i < str.length; i++) {
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code = str.charCodeAt(i);
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if (code < 0x80) out.push(code);
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else if (code < 0x800) {
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out.push(0xc0 | (code >> 6), 0x80 | (code & 0x3f));
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} else if (code < 0xd800 || code >= 0xe000) {
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out.push(0xe0 | (code >> 12), 0x80 | ((code >> 6) & 0x3f), 0x80 | (code & 0x3f));
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} else {
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// surrogate pair
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ch = (code - 0xd800) * 0x400 + (str.charCodeAt(++i) - 0xdc00) + 0x10000;
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out.push(0xf0 | (ch >> 18), 0x80 | ((ch >> 12) & 0x3f), 0x80 | ((ch >> 6) & 0x3f), 0x80 | (ch & 0x3f));
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}
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}
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return new Uint8Array(out);
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}
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function utf8Decode(bytes) {
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if (typeof TextDecoder !== 'undefined') return new TextDecoder('utf-8').decode(bytes);
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var out = '', i = 0, b1, b2, b3, b4, code;
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while (i < bytes.length) {
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b1 = bytes[i++];
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if (b1 < 0x80) { out += String.fromCharCode(b1); }
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else if (b1 < 0xe0) { b2 = bytes[i++]; out += String.fromCharCode(((b1 & 0x1f) << 6) | (b2 & 0x3f)); }
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else if (b1 < 0xf0) {
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b2 = bytes[i++]; b3 = bytes[i++];
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out += String.fromCharCode(((b1 & 0x0f) << 12) | ((b2 & 0x3f) << 6) | (b3 & 0x3f));
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} else {
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b2 = bytes[i++]; b3 = bytes[i++]; b4 = bytes[i++];
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code = ((b1 & 0x07) << 18) | ((b2 & 0x3f) << 12) | ((b3 & 0x3f) << 6) | (b4 & 0x3f);
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code -= 0x10000;
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out += String.fromCharCode(0xd800 + (code >> 10), 0xdc00 + (code & 0x3ff));
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}
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}
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return out;
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}
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function bytesToBin(bytes) {
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var bin = '', i;
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for (i = 0; i < bytes.length; i++) {
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bin += String.fromCharCode(bytes[i]);
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}
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return bin;
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}
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function binToBytes(bin) {
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var out = new Uint8Array(bin.length), i;
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for (i = 0; i < bin.length; i++) out[i] = bin.charCodeAt(i);
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return out;
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}
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/* ---------- Base64（UTF-8 安全） ---------- */
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function b64Encode(str) {
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var bytes = utf8Encode(str);
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// 浏览器环境用 btoa
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if (typeof btoa !== 'undefined') {
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var bin = '';
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for (var i = 0; i < bytes.length; i++) bin += String.fromCharCode(bytes[i]);
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return btoa(bin);
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}
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return global.Base64 && global.Base64.encode(bytesToBin(bytes)) ? global.Base64.encode(bytesToBin(bytes)) : '';
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}
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function b64Decode(b64) {
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b64 = String(b64 || '').replace(/\s+/g, '');
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var bin;
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if (typeof atob !== 'undefined') {
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bin = atob(b64);
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} else if (global.Base64) {
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bin = global.Base64.decode(b64);
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} else {
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throw new Error('当前环境不支持 Base64 解码');
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}
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return utf8Decode(binToBytes(bin));
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}
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/* ---------- Base32（RFC 4648，UTF-8 安全） ---------- */
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var B32_ALPHA = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567';
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function base32Encode(str) {
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var bytes = utf8Encode(str), out = '', bits = 0, value = 0, i;
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for (i = 0; i < bytes.length; i++) {
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value = (value << 8) | bytes[i];
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bits += 8;
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while (bits >= 5) {
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out += B32_ALPHA[(value >>> (bits - 5)) & 31];
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bits -= 5;
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}
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}
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if (bits > 0) out += B32_ALPHA[(value << (5 - bits)) & 31];
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while (out.length % 8 !== 0) out += '=';
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return out;
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}
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function base32Decode(b32) {
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b32 = String(b32 || '').toUpperCase().replace(/[=\s]/g, '');
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if (!b32) return '';
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var bits = 0, value = 0, out = [], i, idx, b;
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for (i = 0; i < b32.length; i++) {
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idx = B32_ALPHA.indexOf(b32[i]);
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if (idx === -1) throw new Error('Base32 字符串包含非法字符: ' + b32[i]);
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value = (value << 5) | idx;
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bits += 5;
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if (bits >= 8) {
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b = (value >>> (bits - 8)) & 0xff;
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out.push(b);
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bits -= 8;
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}
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}
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return utf8Decode(new Uint8Array(out));
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}
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/* ---------- URL 编解码 ---------- */
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function urlEncode(str) { return encodeURIComponent(String(str)); }
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function urlDecode(str) { return decodeURIComponent(String(str).replace(/\+/g, ' ')); }
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/* ---------- Unicode 编解码（支持中文、emoji） ---------- */
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function unicodeEncode(str) {
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str = String(str);
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var out = [], i, code;
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for (i = 0; i < str.length; i++) {
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code = str.charCodeAt(i);
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if (code >= 0xd800 && code <= 0xdbff && i + 1 < str.length) {
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// 代理对：按两个 \uXXXX 输出，JS 自动组合
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out.push('\\u' + code.toString(16).toUpperCase().padStart(4, '0'));
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out.push('\\u' + str.charCodeAt(++i).toString(16).toUpperCase().padStart(4, '0'));
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} else {
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out.push('\\u' + code.toString(16).toUpperCase().padStart(4, '0'));
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}
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}
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return out.join('');
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}
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function unicodeDecode(str) {
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str = String(str);
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// 兼容 \u{1F600} 与 \uXXXX 两种写法
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str = str.replace(/\\u\{([0-9a-fA-F]{1,6})\}/g, function (m, h) {
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var cp = parseInt(h, 16);
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if (cp > 0xffff) {
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cp -= 0x10000;
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return String.fromCharCode(0xd800 + (cp >> 10), 0xdc00 + (cp & 0x3ff));
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}
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return String.fromCharCode(cp);
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});
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str = str.replace(/\\u([0-9a-fA-F]{4})/g, function (m, h) {
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return String.fromCharCode(parseInt(h, 16));
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});
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return str;
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}
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/* ---------- SHA 系列（Web Crypto 原生） ---------- */
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var HASHES = { 'SHA-1': 'SHA-1', 'SHA-256': 'SHA-256', 'SHA-384': 'SHA-384', 'SHA-512': 'SHA-512' };
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function hexFromBuffer(buf) {
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var bytes = new Uint8Array(buf), out = '', i;
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for (i = 0; i < bytes.length; i++) out += bytes[i].toString(16).padStart(2, '0');
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return out;
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}
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function shaDigest(algorithm, text) {
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var bytes = utf8Encode(text);
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if (typeof crypto !== 'undefined' && crypto.subtle) {
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return crypto.subtle.digest(algorithm, bytes).then(hexFromBuffer);
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}
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// 非安全上下文（如普通 http）无 Web Crypto：回退 crypto-js
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return cryptoJsDigest(algorithm, text);
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}
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/* ---------- CryptoJS 懒加载（MD5 / SHA-224 等需要） ---------- */
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var CDN_CRYPTO_JS = [
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'https://cdnjs.cloudflare.com/ajax/libs/crypto-js/4.2.0/crypto-js.min.js',
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'https://cdn.jsdelivr.net/npm/crypto-js@4.2.0/crypto-js.min.js'
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];
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var cryptoJSPromise = null;
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function loadCryptoJS() {
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if (global.CryptoJS) return Promise.resolve(global.CryptoJS);
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if (cryptoJSPromise) return cryptoJSPromise;
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cryptoJSPromise = new Promise(function (resolve) {
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var load = function (idx) {
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if (global.CryptoJS) { resolve(global.CryptoJS); return; }
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if (idx >= CDN_CRYPTO_JS.length) { resolve(null); return; }
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var s = document.createElement('script');
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s.src = CDN_CRYPTO_JS[idx];
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s.onload = function () { resolve(global.CryptoJS || null); };
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s.onerror = function () { load(idx + 1); };
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document.head.appendChild(s);
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};
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load(0);
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});
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return cryptoJSPromise;
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}
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var CRYPTO_JS_METHODS = {
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'MD5': 'MD5', 'SHA-1': 'SHA1', 'SHA-224': 'SHA224',
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'SHA-256': 'SHA256', 'SHA-384': 'SHA384', 'SHA-512': 'SHA512'
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};
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function cryptoJsDigest(algo, text) {
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return loadCryptoJS().then(function (C) {
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if (!C) throw new Error('计算 ' + algo + ' 需要联网加载加密组件（crypto-js）失败，请检查网络');
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var method = CRYPTO_JS_METHODS[algo];
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if (!method || typeof C[method] !== 'function') throw new Error('不支持的算法: ' + algo);
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return C[method](text).toString(C.enc.Hex);
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});
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}
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function hashText(algo, text) {
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if (HASHES[algo]) return shaDigest(HASHES[algo], text);
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if (algo === 'MD5' || algo === 'SHA-224') return cryptoJsDigest(algo, text);
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return Promise.reject(new Error('未知算法: ' + algo));
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}
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/* ---------- 导出 ---------- */
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global.CodecLib = {
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utf8Encode: utf8Encode,
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utf8Decode: utf8Decode,
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b64Encode: b64Encode,
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b64Decode: b64Decode,
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base32Encode: base32Encode,
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base32Decode: base32Decode,
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urlEncode: urlEncode,
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urlDecode: urlDecode,
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unicodeEncode: unicodeEncode,
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unicodeDecode: unicodeDecode,
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hashText: hashText,
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hashes: ['MD5', 'SHA-1', 'SHA-224', 'SHA-256', 'SHA-384', 'SHA-512']
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};
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})(window);
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