Stefan Hacker
434 lines
15 KiB
JavaScript
434 lines
15 KiB
JavaScript
import { ByteStream } from "./byte_stream";
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const pow2_24 = 16777216;
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export class SeqStream {
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constructor(parameters = {}) {
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this._stream = new ByteStream();
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this._length = 0;
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this._start = 0;
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this.backward = false;
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this.appendBlock = 0;
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this.prevLength = 0;
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this.prevStart = 0;
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if ("view" in parameters) {
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this.stream = new ByteStream({ view: parameters.view });
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}
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else if ("buffer" in parameters) {
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this.stream = new ByteStream({ buffer: parameters.buffer });
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}
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else if ("string" in parameters) {
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this.stream = new ByteStream({ string: parameters.string });
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}
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else if ("hexstring" in parameters) {
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this.stream = new ByteStream({ hexstring: parameters.hexstring });
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}
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else if ("stream" in parameters) {
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this.stream = parameters.stream.slice();
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}
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else {
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this.stream = new ByteStream();
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}
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if ("backward" in parameters && parameters.backward) {
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this.backward = parameters.backward;
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this._start = this.stream.length;
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}
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if ("length" in parameters && parameters.length > 0) {
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this._length = parameters.length;
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}
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if ("start" in parameters && parameters.start && parameters.start > 0) {
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this._start = parameters.start;
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}
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if ("appendBlock" in parameters && parameters.appendBlock && parameters.appendBlock > 0) {
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this.appendBlock = parameters.appendBlock;
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}
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}
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set stream(value) {
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this._stream = value;
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this.prevLength = this._length;
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this._length = value.length;
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this.prevStart = this._start;
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this._start = 0;
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}
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get stream() {
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return this._stream;
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}
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set length(value) {
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this.prevLength = this._length;
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this._length = value;
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}
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get length() {
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if (this.appendBlock) {
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return this.start;
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}
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return this._length;
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}
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set start(value) {
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if (value > this.stream.length)
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return;
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this.prevStart = this._start;
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this.prevLength = this._length;
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this._length -= (this.backward) ? (this._start - value) : (value - this._start);
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this._start = value;
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}
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get start() {
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return this._start;
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}
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get buffer() {
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return this._stream.buffer.slice(0, this._length);
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}
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resetPosition() {
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this._start = this.prevStart;
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this._length = this.prevLength;
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}
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findPattern(pattern, gap = null) {
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if ((gap == null) || (gap > this.length)) {
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gap = this.length;
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}
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const result = this.stream.findPattern(pattern, this.start, this.length, this.backward);
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if (result == (-1))
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return result;
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if (this.backward) {
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if (result < (this.start - pattern.length - gap)) {
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return (-1);
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}
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}
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else {
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if (result > (this.start + pattern.length + gap)) {
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return (-1);
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}
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}
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this.start = result;
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return result;
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}
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findFirstIn(patterns, gap = null) {
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if ((gap == null) || (gap > this.length)) {
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gap = this.length;
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}
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const result = this.stream.findFirstIn(patterns, this.start, this.length, this.backward);
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if (result.id == (-1))
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return result;
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if (this.backward) {
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if (result.position < (this.start - patterns[result.id].length - gap)) {
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return {
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id: (-1),
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position: (this.backward) ? 0 : (this.start + this.length)
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};
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}
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}
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else {
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if (result.position > (this.start + patterns[result.id].length + gap)) {
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return {
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id: (-1),
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position: (this.backward) ? 0 : (this.start + this.length)
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};
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}
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}
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this.start = result.position;
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return result;
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}
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findAllIn(patterns) {
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const start = (this.backward) ? (this.start - this.length) : this.start;
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return this.stream.findAllIn(patterns, start, this.length);
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}
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findFirstNotIn(patterns, gap = null) {
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if ((gap == null) || (gap > this._length)) {
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gap = this._length;
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}
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const result = this._stream.findFirstNotIn(patterns, this._start, this._length, this.backward);
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if ((result.left.id == (-1)) && (result.right.id == (-1))) {
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return result;
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}
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if (this.backward) {
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if (result.right.id != (-1)) {
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if (result.right.position < (this._start - patterns[result.right.id].length - gap)) {
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return {
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left: {
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id: (-1),
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position: this._start
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},
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right: {
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id: (-1),
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position: 0
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},
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value: new ByteStream()
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};
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}
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}
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}
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else {
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if (result.left.id != (-1)) {
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if (result.left.position > (this._start + patterns[result.left.id].length + gap)) {
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return {
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left: {
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id: (-1),
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position: this._start
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},
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right: {
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id: (-1),
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position: 0
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},
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value: new ByteStream()
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};
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}
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}
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}
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if (this.backward) {
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if (result.left.id == (-1)) {
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this.start = 0;
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}
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else {
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this.start = result.left.position;
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}
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}
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else {
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if (result.right.id == (-1)) {
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this.start = (this._start + this._length);
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}
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else {
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this.start = result.right.position;
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}
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}
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return result;
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}
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findAllNotIn(patterns) {
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const start = (this.backward) ? (this._start - this._length) : this._start;
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return this._stream.findAllNotIn(patterns, start, this._length);
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}
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findFirstSequence(patterns, length = null, gap = null) {
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if ((length == null) || (length > this._length)) {
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length = this._length;
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}
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if ((gap == null) || (gap > length)) {
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gap = length;
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}
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const result = this._stream.findFirstSequence(patterns, this._start, length, this.backward);
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if (result.value.length == 0) {
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return result;
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}
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if (this.backward) {
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if (result.position < (this._start - result.value.length - gap)) {
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return {
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position: (-1),
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value: new ByteStream()
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};
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}
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}
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else {
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if (result.position > (this._start + result.value.length + gap)) {
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return {
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position: (-1),
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value: new ByteStream()
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};
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}
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}
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this.start = result.position;
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return result;
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}
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findAllSequences(patterns) {
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const start = (this.backward) ? (this.start - this.length) : this.start;
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return this.stream.findAllSequences(patterns, start, this.length);
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}
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findPairedPatterns(leftPattern, rightPattern, gap = null) {
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if ((gap == null) || (gap > this.length)) {
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gap = this.length;
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}
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const start = (this.backward) ? (this.start - this.length) : this.start;
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const result = this.stream.findPairedPatterns(leftPattern, rightPattern, start, this.length);
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if (result.length) {
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if (this.backward) {
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if (result[0].right < (this.start - rightPattern.length - gap)) {
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return [];
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}
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}
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else {
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if (result[0].left > (this.start + leftPattern.length + gap)) {
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return [];
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}
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}
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}
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return result;
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}
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findPairedArrays(leftPatterns, rightPatterns, gap = null) {
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if ((gap == null) || (gap > this.length)) {
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gap = this.length;
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}
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const start = (this.backward) ? (this.start - this.length) : this.start;
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const result = this.stream.findPairedArrays(leftPatterns, rightPatterns, start, this.length);
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if (result.length) {
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if (this.backward) {
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if (result[0].right.position < (this.start - rightPatterns[result[0].right.id].length - gap)) {
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return [];
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}
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}
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else {
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if (result[0].left.position > (this.start + leftPatterns[result[0].left.id].length + gap)) {
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return [];
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}
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}
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}
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return result;
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}
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replacePattern(searchPattern, replacePattern) {
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const start = (this.backward) ? (this.start - this.length) : this.start;
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return this.stream.replacePattern(searchPattern, replacePattern, start, this.length);
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}
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skipPatterns(patterns) {
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const result = this.stream.skipPatterns(patterns, this.start, this.length, this.backward);
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this.start = result;
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return result;
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}
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skipNotPatterns(patterns) {
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const result = this.stream.skipNotPatterns(patterns, this.start, this.length, this.backward);
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if (result == (-1))
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return (-1);
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this.start = result;
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return result;
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}
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append(stream) {
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this.beforeAppend(stream.length);
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this._stream.view.set(stream.view, this._start);
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this._length += (stream.length * 2);
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this.start = (this._start + stream.length);
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this.prevLength -= (stream.length * 2);
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}
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appendView(view) {
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this.beforeAppend(view.length);
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this._stream.view.set(view, this._start);
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this._length += (view.length * 2);
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this.start = (this._start + view.length);
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this.prevLength -= (view.length * 2);
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}
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appendChar(char) {
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this.beforeAppend(1);
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this._stream.view[this._start] = char;
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this._length += 2;
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this.start = (this._start + 1);
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this.prevLength -= 2;
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}
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appendUint16(number) {
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this.beforeAppend(2);
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const value = new Uint16Array([number]);
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const view = new Uint8Array(value.buffer);
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this.stream.view[this._start] = view[1];
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this._stream.view[this._start + 1] = view[0];
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this._length += 4;
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this.start = this._start + 2;
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this.prevLength -= 4;
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}
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appendUint24(number) {
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this.beforeAppend(3);
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const value = new Uint32Array([number]);
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const view = new Uint8Array(value.buffer);
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this._stream.view[this._start] = view[2];
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this._stream.view[this._start + 1] = view[1];
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this._stream.view[this._start + 2] = view[0];
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this._length += 6;
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this.start = (this._start + 3);
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this.prevLength -= 6;
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}
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appendUint32(number) {
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this.beforeAppend(4);
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const value = new Uint32Array([number]);
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const view = new Uint8Array(value.buffer);
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this._stream.view[this._start] = view[3];
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this._stream.view[this._start + 1] = view[2];
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this._stream.view[this._start + 2] = view[1];
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this._stream.view[this._start + 3] = view[0];
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this._length += 8;
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this.start = (this._start + 4);
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this.prevLength -= 8;
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}
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appendInt16(number) {
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this.beforeAppend(2);
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const value = new Int16Array([number]);
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const view = new Uint8Array(value.buffer);
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this._stream.view[this._start] = view[1];
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this._stream.view[this._start + 1] = view[0];
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this._length += 4;
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this.start = (this._start + 2);
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this.prevLength -= 4;
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}
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appendInt32(number) {
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this.beforeAppend(4);
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const value = new Int32Array([number]);
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const view = new Uint8Array(value.buffer);
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this._stream.view[this._start] = view[3];
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this._stream.view[this._start + 1] = view[2];
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this._stream.view[this._start + 2] = view[1];
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this._stream.view[this._start + 3] = view[0];
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this._length += 8;
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this.start = (this._start + 4);
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this.prevLength -= 8;
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}
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getBlock(size, changeLength = true) {
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if (this._length <= 0) {
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return new Uint8Array(0);
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}
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if (this._length < size) {
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size = this._length;
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}
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let result;
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if (this.backward) {
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const view = this._stream.view.subarray(this._length - size, this._length);
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result = new Uint8Array(size);
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for (let i = 0; i < size; i++) {
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result[size - 1 - i] = view[i];
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}
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}
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else {
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result = this._stream.view.subarray(this._start, this._start + size);
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}
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if (changeLength) {
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this.start += ((this.backward) ? ((-1) * size) : size);
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}
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return result;
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}
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getUint16(changeLength = true) {
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const block = this.getBlock(2, changeLength);
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if (block.length < 2)
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return 0;
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return (block[0] << 8) | block[1];
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}
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getInt16(changeLength = true) {
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const num = this.getUint16(changeLength);
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const negative = 0x8000;
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if (num & negative) {
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return -(negative - (num ^ negative));
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}
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return num;
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}
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getUint24(changeLength = true) {
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const block = this.getBlock(4, changeLength);
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if (block.length < 3)
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return 0;
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return (block[0] << 16) |
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(block[1] << 8) |
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block[2];
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}
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getUint32(changeLength = true) {
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const block = this.getBlock(4, changeLength);
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if (block.length < 4)
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return 0;
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return (block[0] * pow2_24) +
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(block[1] << 16) +
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(block[2] << 8) +
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block[3];
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}
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getInt32(changeLength = true) {
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const num = this.getUint32(changeLength);
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const negative = 0x80000000;
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if (num & negative) {
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return -(negative - (num ^ negative));
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}
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return num;
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}
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beforeAppend(size) {
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if ((this._start + size) > this._stream.length) {
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if (size > this.appendBlock) {
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this.appendBlock = size + SeqStream.APPEND_BLOCK;
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}
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this._stream.realloc(this._stream.length + this.appendBlock);
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}
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}
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}
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SeqStream.APPEND_BLOCK = 1000;
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