4df82ad31e
Unless you actually need to check that something is both a `Dict` and also of the *correct* type, using `instanceof Dict` directly should be a tiny bit more efficient since it avoids one function call and an unnecessary `undefined` check. This patch uses ESLint to enforce this, since we obviously still want to keep the `isDict` helper function for where it makes sense.
61 lines
1.7 KiB
JavaScript
61 lines
1.7 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 { CCITTFaxDecoder } from "./ccitt.js";
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import { DecodeStream } from "./decode_stream.js";
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import { Dict } from "./primitives.js";
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class CCITTFaxStream extends DecodeStream {
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constructor(str, maybeLength, params) {
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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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if (!(params instanceof Dict)) {
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params = Dict.empty;
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}
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const source = {
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next() {
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return str.getByte();
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},
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};
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this.ccittFaxDecoder = new CCITTFaxDecoder(source, {
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K: params.get("K"),
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EndOfLine: params.get("EndOfLine"),
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EncodedByteAlign: params.get("EncodedByteAlign"),
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Columns: params.get("Columns"),
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Rows: params.get("Rows"),
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EndOfBlock: params.get("EndOfBlock"),
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BlackIs1: params.get("BlackIs1"),
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});
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}
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readBlock() {
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while (!this.eof) {
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const c = this.ccittFaxDecoder.readNextChar();
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if (c === -1) {
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this.eof = true;
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return;
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}
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this.ensureBuffer(this.bufferLength + 1);
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this.buffer[this.bufferLength++] = c;
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}
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}
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}
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export { CCITTFaxStream };
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