60 lines
1.6 KiB
JavaScript
60 lines
1.6 KiB
JavaScript
/* Copyright 2012 Mozilla Foundation
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*
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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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import { DecodeStream } from "./decode_stream.js";
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const chunkSize = 512;
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class DecryptStream extends DecodeStream {
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constructor(str, maybeLength, decrypt) {
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super(maybeLength);
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this.str = str;
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this.dict = str.dict;
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this.decrypt = decrypt;
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this.nextChunk = null;
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this.initialized = false;
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}
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readBlock() {
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let chunk;
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if (this.initialized) {
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chunk = this.nextChunk;
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} else {
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chunk = this.str.getBytes(chunkSize);
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this.initialized = true;
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}
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if (!chunk || chunk.length === 0) {
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this.eof = true;
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return;
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}
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this.nextChunk = this.str.getBytes(chunkSize);
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const hasMoreData = this.nextChunk && this.nextChunk.length > 0;
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const decrypt = this.decrypt;
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chunk = decrypt(chunk, !hasMoreData);
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let bufferLength = this.bufferLength;
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const n = chunk.length,
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buffer = this.ensureBuffer(bufferLength + n);
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for (let i = 0; i < n; i++) {
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buffer[bufferLength++] = chunk[i];
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}
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this.bufferLength = bufferLength;
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}
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}
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export { DecryptStream };
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