67415bfabe
By having an abstract base-class, it becomes a lot clearer exactly which methods/getters are expected to exist on all Stream instances. Furthermore, since a number of the methods are *identical* for all Stream implementations, this reduces unnecessary code duplication in the `Stream`, `DecodeStream`, and `ChunkedStream` classes. For e.g. `gulp mozcentral`, the *built* `pdf.worker.js` files decreases from `1 619 329` to `1 616 115` bytes with this patch-series.
104 lines
2.4 KiB
JavaScript
104 lines
2.4 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 { BaseStream } from "./base_stream.js";
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import { stringToBytes } from "../shared/util.js";
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class Stream extends BaseStream {
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constructor(arrayBuffer, start, length, dict) {
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super();
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this.bytes =
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arrayBuffer instanceof Uint8Array
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? arrayBuffer
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: new Uint8Array(arrayBuffer);
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this.start = start || 0;
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this.pos = this.start;
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this.end = start + length || this.bytes.length;
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this.dict = dict;
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}
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get length() {
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return this.end - this.start;
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}
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get isEmpty() {
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return this.length === 0;
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}
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getByte() {
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if (this.pos >= this.end) {
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return -1;
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}
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return this.bytes[this.pos++];
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}
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getBytes(length, forceClamped = false) {
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const bytes = this.bytes;
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const pos = this.pos;
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const strEnd = this.end;
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if (!length) {
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const subarray = bytes.subarray(pos, strEnd);
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// `this.bytes` is always a `Uint8Array` here.
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return forceClamped ? new Uint8ClampedArray(subarray) : subarray;
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}
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let end = pos + length;
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if (end > strEnd) {
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end = strEnd;
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}
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this.pos = end;
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const subarray = bytes.subarray(pos, end);
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// `this.bytes` is always a `Uint8Array` here.
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return forceClamped ? new Uint8ClampedArray(subarray) : subarray;
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}
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getByteRange(begin, end) {
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if (begin < 0) {
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begin = 0;
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}
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if (end > this.end) {
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end = this.end;
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}
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return this.bytes.subarray(begin, end);
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}
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reset() {
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this.pos = this.start;
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}
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moveStart() {
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this.start = this.pos;
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}
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makeSubStream(start, length, dict = null) {
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return new Stream(this.bytes.buffer, start, length, dict);
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}
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}
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class StringStream extends Stream {
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constructor(str) {
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super(stringToBytes(str));
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}
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}
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class NullStream extends Stream {
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constructor() {
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super(new Uint8Array(0));
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}
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}
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export { NullStream, Stream, StringStream };
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