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47 lines
1.9 KiB
47 lines
1.9 KiB
"use strict"; |
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Object.defineProperty(exports, "__esModule", { value: true }); |
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exports.decode = exports.encode = void 0; |
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const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'; |
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// Use a lookup table to find the index. |
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const lookup = typeof Uint8Array === 'undefined' ? [] : new Uint8Array(256); |
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for (let i = 0; i < chars.length; i++) { |
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lookup[chars.charCodeAt(i)] = i; |
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} |
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const encode = (arraybuffer) => { |
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let bytes = new Uint8Array(arraybuffer), i, len = bytes.length, base64 = ''; |
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for (i = 0; i < len; i += 3) { |
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base64 += chars[bytes[i] >> 2]; |
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base64 += chars[((bytes[i] & 3) << 4) | (bytes[i + 1] >> 4)]; |
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base64 += chars[((bytes[i + 1] & 15) << 2) | (bytes[i + 2] >> 6)]; |
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base64 += chars[bytes[i + 2] & 63]; |
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} |
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if (len % 3 === 2) { |
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base64 = base64.substring(0, base64.length - 1) + '='; |
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} |
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else if (len % 3 === 1) { |
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base64 = base64.substring(0, base64.length - 2) + '=='; |
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} |
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return base64; |
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}; |
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exports.encode = encode; |
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const decode = (base64) => { |
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let bufferLength = base64.length * 0.75, len = base64.length, i, p = 0, encoded1, encoded2, encoded3, encoded4; |
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if (base64[base64.length - 1] === '=') { |
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bufferLength--; |
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if (base64[base64.length - 2] === '=') { |
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bufferLength--; |
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} |
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} |
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const arraybuffer = new ArrayBuffer(bufferLength), bytes = new Uint8Array(arraybuffer); |
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for (i = 0; i < len; i += 4) { |
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encoded1 = lookup[base64.charCodeAt(i)]; |
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encoded2 = lookup[base64.charCodeAt(i + 1)]; |
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encoded3 = lookup[base64.charCodeAt(i + 2)]; |
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encoded4 = lookup[base64.charCodeAt(i + 3)]; |
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bytes[p++] = (encoded1 << 2) | (encoded2 >> 4); |
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bytes[p++] = ((encoded2 & 15) << 4) | (encoded3 >> 2); |
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bytes[p++] = ((encoded3 & 3) << 6) | (encoded4 & 63); |
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} |
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return arraybuffer; |
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}; |
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exports.decode = decode;
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