"use strict";
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const bigint = require('./bigint');
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const SHIFT_LEFT_32 = (1 << 16) * (1 << 16);
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const SHIFT_RIGHT_32 = 1 / SHIFT_LEFT_32;
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const UNKNOWN_PLP_LEN = Buffer.from([0xfe, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff]);
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const ZERO_LENGTH_BUFFER = Buffer.alloc(0);
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/*
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A Buffer-like class that tracks position.
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As values are written, the position advances by the size of the written data.
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When writing, automatically allocates new buffers if there's not enough space.
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*/
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module.exports = class WritableTrackingBuffer {
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constructor(initialSize, encoding, doubleSizeGrowth) {
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this.initialSize = initialSize;
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this.encoding = encoding || 'ucs2';
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this.doubleSizeGrowth = doubleSizeGrowth || false;
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this.buffer = Buffer.alloc(this.initialSize, 0);
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this.compositeBuffer = ZERO_LENGTH_BUFFER;
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this.position = 0;
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} // $FlowFixMe: Flow does not like getter/setters that have side-effects.
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get data() {
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this.newBuffer(0);
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return this.compositeBuffer;
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}
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copyFrom(buffer) {
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const length = buffer.length;
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this.makeRoomFor(length);
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buffer.copy(this.buffer, this.position);
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this.position += length;
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}
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makeRoomFor(requiredLength) {
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if (this.buffer.length - this.position < requiredLength) {
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if (this.doubleSizeGrowth) {
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let size = Math.max(128, this.buffer.length * 2);
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while (size < requiredLength) {
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size *= 2;
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}
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this.newBuffer(size);
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} else {
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this.newBuffer(requiredLength);
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}
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}
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}
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newBuffer(size) {
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const buffer = this.buffer.slice(0, this.position);
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this.compositeBuffer = Buffer.concat([this.compositeBuffer, buffer]);
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this.buffer = size === 0 ? ZERO_LENGTH_BUFFER : Buffer.alloc(size, 0);
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this.position = 0;
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}
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writeUInt8(value) {
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const length = 1;
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this.makeRoomFor(length);
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this.buffer.writeUInt8(value, this.position);
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this.position += length;
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}
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writeUInt16LE(value) {
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const length = 2;
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this.makeRoomFor(length);
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this.buffer.writeUInt16LE(value, this.position);
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this.position += length;
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}
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writeUShort(value) {
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this.writeUInt16LE(value);
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}
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writeUInt16BE(value) {
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const length = 2;
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this.makeRoomFor(length);
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this.buffer.writeUInt16BE(value, this.position);
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this.position += length;
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}
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writeUInt24LE(value) {
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const length = 3;
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this.makeRoomFor(length);
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this.buffer[this.position + 2] = value >>> 16 & 0xff;
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this.buffer[this.position + 1] = value >>> 8 & 0xff;
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this.buffer[this.position] = value & 0xff;
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this.position += length;
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}
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writeUInt32LE(value) {
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const length = 4;
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this.makeRoomFor(length);
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this.buffer.writeUInt32LE(value, this.position);
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this.position += length;
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}
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writeInt64LE(value) {
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const buf = bigint.numberToInt64LE(value);
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this.copyFrom(buf);
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}
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writeUInt32BE(value) {
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const length = 4;
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this.makeRoomFor(length);
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this.buffer.writeUInt32BE(value, this.position);
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this.position += length;
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}
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writeUInt40LE(value) {
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// inspired by https://github.com/dpw/node-buffer-more-ints
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this.writeInt32LE(value & -1);
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this.writeUInt8(Math.floor(value * SHIFT_RIGHT_32));
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}
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writeUInt64LE(value) {
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this.writeInt32LE(value & -1);
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this.writeUInt32LE(Math.floor(value * SHIFT_RIGHT_32));
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}
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writeInt8(value) {
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const length = 1;
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this.makeRoomFor(length);
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this.buffer.writeInt8(value, this.position);
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this.position += length;
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}
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writeInt16LE(value) {
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const length = 2;
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this.makeRoomFor(length);
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this.buffer.writeInt16LE(value, this.position);
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this.position += length;
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}
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writeInt16BE(value) {
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const length = 2;
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this.makeRoomFor(length);
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this.buffer.writeInt16BE(value, this.position);
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this.position += length;
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}
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writeInt32LE(value) {
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const length = 4;
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this.makeRoomFor(length);
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this.buffer.writeInt32LE(value, this.position);
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this.position += length;
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}
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writeInt32BE(value) {
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const length = 4;
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this.makeRoomFor(length);
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this.buffer.writeInt32BE(value, this.position);
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this.position += length;
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}
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writeFloatLE(value) {
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const length = 4;
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this.makeRoomFor(length);
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this.buffer.writeFloatLE(value, this.position);
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this.position += length;
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}
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writeDoubleLE(value) {
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const length = 8;
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this.makeRoomFor(length);
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this.buffer.writeDoubleLE(value, this.position);
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this.position += length;
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}
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writeString(value, encoding) {
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if (encoding == undefined) {
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encoding = this.encoding;
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}
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const length = Buffer.byteLength(value, encoding);
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this.makeRoomFor(length); // $FlowFixMe https://github.com/facebook/flow/pull/5398
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this.buffer.write(value, this.position, encoding);
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this.position += length;
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}
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writeBVarchar(value, encoding) {
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this.writeUInt8(value.length);
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this.writeString(value, encoding);
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}
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writeUsVarchar(value, encoding) {
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this.writeUInt16LE(value.length);
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this.writeString(value, encoding);
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} // TODO: Figure out what types are passed in other than `Buffer`
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writeUsVarbyte(value, encoding) {
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if (encoding == undefined) {
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encoding = this.encoding;
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}
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let length;
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if (value instanceof Buffer) {
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length = value.length;
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} else {
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value = value.toString();
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length = Buffer.byteLength(value, encoding);
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}
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this.writeUInt16LE(length);
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if (value instanceof Buffer) {
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this.writeBuffer(value);
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} else {
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this.makeRoomFor(length); // $FlowFixMe https://github.com/facebook/flow/pull/5398
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this.buffer.write(value, this.position, encoding);
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this.position += length;
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}
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}
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writePLPBody(value, encoding) {
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if (encoding == null) {
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encoding = this.encoding;
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}
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let length;
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if (value instanceof Buffer) {
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length = value.length;
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} else {
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value = value.toString();
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length = Buffer.byteLength(value, encoding);
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} // Length of all chunks.
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// this.writeUInt64LE(length);
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// unknown seems to work better here - might revisit later.
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this.writeBuffer(UNKNOWN_PLP_LEN); // In the UNKNOWN_PLP_LEN case, the data is represented as a series of zero or more chunks.
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if (length > 0) {
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// One chunk.
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this.writeUInt32LE(length);
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if (value instanceof Buffer) {
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this.writeBuffer(value);
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} else {
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this.makeRoomFor(length); // $FlowFixMe https://github.com/facebook/flow/pull/5398
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this.buffer.write(value, this.position, encoding);
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this.position += length;
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}
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} // PLP_TERMINATOR (no more chunks).
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this.writeUInt32LE(0);
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}
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writeBuffer(value) {
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const length = value.length;
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this.makeRoomFor(length);
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value.copy(this.buffer, this.position);
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this.position += length;
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}
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writeMoney(value) {
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this.writeInt32LE(Math.floor(value * SHIFT_RIGHT_32));
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this.writeInt32LE(value & -1);
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}
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};
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