Convert src/core/decode_stream.js to use standard classes
This commit is contained in:
Jonas Jenwald
parent
8ce2cae4a7
commit
b11f012e52
@ -16,16 +16,15 @@
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import { Stream } from "./stream.js";
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import { unreachable } from "../shared/util.js";
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// super class for the decoding streams
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const DecodeStream = (function DecodeStreamClosure() {
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// Lots of DecodeStreams are created whose buffers are never used. For these
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// we share a single empty buffer. This is (a) space-efficient and (b) avoids
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// having special cases that would be required if we used |null| for an empty
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// buffer.
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const emptyBuffer = new Uint8Array(0);
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// Lots of DecodeStreams are created whose buffers are never used. For these
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// we share a single empty buffer. This is (a) space-efficient and (b) avoids
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// having special cases that would be required if we used |null| for an empty
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// buffer.
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const emptyBuffer = new Uint8Array(0);
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// eslint-disable-next-line no-shadow
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function DecodeStream(maybeMinBufferLength) {
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// Super class for the decoding streams.
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class DecodeStream {
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constructor(maybeMinBufferLength) {
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this._rawMinBufferLength = maybeMinBufferLength || 0;
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this.pos = 0;
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@ -41,155 +40,156 @@ const DecodeStream = (function DecodeStreamClosure() {
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}
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}
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DecodeStream.prototype = {
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// eslint-disable-next-line getter-return
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get length() {
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unreachable("Should not access DecodeStream.length");
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},
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get isEmpty() {
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while (!this.eof && this.bufferLength === 0) {
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this.readBlock();
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}
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return this.bufferLength === 0;
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},
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ensureBuffer: function DecodeStream_ensureBuffer(requested) {
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const buffer = this.buffer;
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if (requested <= buffer.byteLength) {
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return buffer;
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}
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let size = this.minBufferLength;
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while (size < requested) {
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size *= 2;
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}
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const buffer2 = new Uint8Array(size);
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buffer2.set(buffer);
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return (this.buffer = buffer2);
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},
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getByte: function DecodeStream_getByte() {
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const pos = this.pos;
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while (this.bufferLength <= pos) {
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if (this.eof) {
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return -1;
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}
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this.readBlock();
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}
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return this.buffer[this.pos++];
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},
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getUint16: function DecodeStream_getUint16() {
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const b0 = this.getByte();
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const b1 = this.getByte();
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if (b0 === -1 || b1 === -1) {
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return -1;
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}
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return (b0 << 8) + b1;
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},
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getInt32: function DecodeStream_getInt32() {
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const b0 = this.getByte();
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const b1 = this.getByte();
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const b2 = this.getByte();
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const b3 = this.getByte();
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return (b0 << 24) + (b1 << 16) + (b2 << 8) + b3;
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},
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getBytes(length, forceClamped = false) {
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const pos = this.pos;
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let end;
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if (length) {
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this.ensureBuffer(pos + length);
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end = pos + length;
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while (!this.eof && this.bufferLength < end) {
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this.readBlock();
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}
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const bufEnd = this.bufferLength;
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if (end > bufEnd) {
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end = bufEnd;
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}
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} else {
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while (!this.eof) {
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this.readBlock();
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}
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end = this.bufferLength;
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}
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this.pos = end;
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const subarray = this.buffer.subarray(pos, end);
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// `this.buffer` is either a `Uint8Array` or `Uint8ClampedArray` here.
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return forceClamped && !(subarray instanceof Uint8ClampedArray)
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? new Uint8ClampedArray(subarray)
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: subarray;
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},
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peekByte: function DecodeStream_peekByte() {
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const peekedByte = this.getByte();
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if (peekedByte !== -1) {
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this.pos--;
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}
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return peekedByte;
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},
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peekBytes(length, forceClamped = false) {
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const bytes = this.getBytes(length, forceClamped);
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this.pos -= bytes.length;
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return bytes;
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},
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makeSubStream: function DecodeStream_makeSubStream(start, length, dict) {
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if (length === undefined) {
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while (!this.eof) {
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this.readBlock();
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}
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} else {
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const end = start + length;
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while (this.bufferLength <= end && !this.eof) {
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this.readBlock();
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}
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}
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return new Stream(this.buffer, start, length, dict);
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},
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getByteRange(begin, end) {
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unreachable("Should not call DecodeStream.getByteRange");
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},
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skip: function DecodeStream_skip(n) {
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if (!n) {
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n = 1;
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}
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this.pos += n;
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},
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reset: function DecodeStream_reset() {
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this.pos = 0;
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},
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getBaseStreams: function DecodeStream_getBaseStreams() {
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if (this.str && this.str.getBaseStreams) {
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return this.str.getBaseStreams();
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}
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return [];
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},
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};
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return DecodeStream;
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})();
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const StreamsSequenceStream = (function StreamsSequenceStreamClosure() {
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// eslint-disable-next-line no-shadow
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function StreamsSequenceStream(streams) {
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this.streams = streams;
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let maybeLength = 0;
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for (let i = 0, ii = streams.length; i < ii; i++) {
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const stream = streams[i];
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if (stream instanceof DecodeStream) {
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maybeLength += stream._rawMinBufferLength;
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} else {
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maybeLength += stream.length;
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}
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}
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DecodeStream.call(this, maybeLength);
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// eslint-disable-next-line getter-return
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get length() {
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unreachable("Should not access DecodeStream.length");
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}
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StreamsSequenceStream.prototype = Object.create(DecodeStream.prototype);
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get isEmpty() {
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while (!this.eof && this.bufferLength === 0) {
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this.readBlock();
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}
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return this.bufferLength === 0;
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}
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StreamsSequenceStream.prototype.readBlock = function streamSequenceStreamReadBlock() {
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ensureBuffer(requested) {
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const buffer = this.buffer;
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if (requested <= buffer.byteLength) {
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return buffer;
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}
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let size = this.minBufferLength;
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while (size < requested) {
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size *= 2;
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}
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const buffer2 = new Uint8Array(size);
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buffer2.set(buffer);
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return (this.buffer = buffer2);
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}
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getByte() {
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const pos = this.pos;
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while (this.bufferLength <= pos) {
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if (this.eof) {
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return -1;
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}
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this.readBlock();
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}
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return this.buffer[this.pos++];
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}
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getUint16() {
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const b0 = this.getByte();
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const b1 = this.getByte();
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if (b0 === -1 || b1 === -1) {
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return -1;
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}
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return (b0 << 8) + b1;
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}
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getInt32() {
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const b0 = this.getByte();
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const b1 = this.getByte();
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const b2 = this.getByte();
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const b3 = this.getByte();
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return (b0 << 24) + (b1 << 16) + (b2 << 8) + b3;
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}
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getBytes(length, forceClamped = false) {
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const pos = this.pos;
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let end;
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if (length) {
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this.ensureBuffer(pos + length);
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end = pos + length;
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while (!this.eof && this.bufferLength < end) {
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this.readBlock();
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}
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const bufEnd = this.bufferLength;
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if (end > bufEnd) {
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end = bufEnd;
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}
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} else {
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while (!this.eof) {
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this.readBlock();
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}
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end = this.bufferLength;
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}
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this.pos = end;
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const subarray = this.buffer.subarray(pos, end);
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// `this.buffer` is either a `Uint8Array` or `Uint8ClampedArray` here.
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return forceClamped && !(subarray instanceof Uint8ClampedArray)
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? new Uint8ClampedArray(subarray)
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: subarray;
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}
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peekByte() {
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const peekedByte = this.getByte();
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if (peekedByte !== -1) {
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this.pos--;
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}
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return peekedByte;
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}
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peekBytes(length, forceClamped = false) {
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const bytes = this.getBytes(length, forceClamped);
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this.pos -= bytes.length;
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return bytes;
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}
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makeSubStream(start, length, dict = null) {
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if (length === undefined) {
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while (!this.eof) {
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this.readBlock();
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}
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} else {
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const end = start + length;
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while (this.bufferLength <= end && !this.eof) {
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this.readBlock();
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}
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}
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return new Stream(this.buffer, start, length, dict);
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}
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getByteRange(begin, end) {
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unreachable("Should not call DecodeStream.getByteRange");
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}
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skip(n) {
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if (!n) {
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n = 1;
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}
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this.pos += n;
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}
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reset() {
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this.pos = 0;
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}
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getBaseStreams() {
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if (this.str && this.str.getBaseStreams) {
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return this.str.getBaseStreams();
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}
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return [];
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}
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}
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class StreamsSequenceStream extends DecodeStream {
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constructor(streams) {
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let maybeLength = 0;
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for (const stream of streams) {
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maybeLength +=
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stream instanceof DecodeStream
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? stream._rawMinBufferLength
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: stream.length;
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}
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super(maybeLength);
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this.streams = streams;
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}
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readBlock() {
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const streams = this.streams;
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if (streams.length === 0) {
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this.eof = true;
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@ -202,20 +202,17 @@ const StreamsSequenceStream = (function StreamsSequenceStreamClosure() {
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const buffer = this.ensureBuffer(newLength);
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buffer.set(chunk, bufferLength);
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this.bufferLength = newLength;
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};
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}
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StreamsSequenceStream.prototype.getBaseStreams = function StreamsSequenceStream_getBaseStreams() {
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getBaseStreams() {
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const baseStreams = [];
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for (let i = 0, ii = this.streams.length; i < ii; i++) {
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const stream = this.streams[i];
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for (const stream of this.streams) {
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if (stream.getBaseStreams) {
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baseStreams.push(...stream.getBaseStreams());
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}
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}
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return baseStreams;
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};
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return StreamsSequenceStream;
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})();
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}
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}
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export { DecodeStream, StreamsSequenceStream };
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