86 lines
2.6 KiB
Plaintext
86 lines
2.6 KiB
Plaintext
/*
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* Copyright (C) 2021 Huawei Device Co., Ltd.
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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export class Base64 {
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lookup: Uint8Array = new Uint8Array(256)
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chars: string = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
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private static sInstance: Base64;
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public static getInstance(): Base64{
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if (!this.sInstance) {
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this.sInstance = new Base64();
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}
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return this.sInstance;
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}
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private constructor() {
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console.log("Base64 - constructor init!")
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for (var index = 0; index < this.chars.length; index++) {
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this.lookup[this.chars.charCodeAt(index)] = index;
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}
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}
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encode(arraybuffer: ArrayBuffer): string {
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let bytes = new Uint8Array(arraybuffer),
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i,
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len = bytes.length,
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base64 = '';
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for (i = 0; i < len; i += 3) {
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base64 += this.chars[bytes[i] >> 2];
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base64 += this.chars[((bytes[i] & 3) << 4) | (bytes[i + 1] >> 4)];
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base64 += this.chars[((bytes[i + 1] & 15) << 2) | (bytes[i + 2] >> 6)];
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base64 += this.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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} 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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decode(base64: string): ArrayBuffer{
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let bufferLength = base64.length * 0.75,
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len = base64.length,
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i,
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p = 0,
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encoded1,
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encoded2,
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encoded3,
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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),
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bytes = new Uint8Array(arraybuffer);
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for (i = 0; i < len; i += 4) {
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encoded1 = this.lookup[base64.charCodeAt(i)];
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encoded2 = this.lookup[base64.charCodeAt(i + 1)];
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encoded3 = this.lookup[base64.charCodeAt(i + 2)];
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encoded4 = this.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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} |