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pack.js
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"use strict"
let unpackModule = require('./unpack')
let Unpackr = unpackModule.Unpackr
let mult10 = unpackModule.mult10
let C1Type = unpackModule.C1Type
const typedArrays = unpackModule.typedArrays
let textEncoder
try {
textEncoder = new TextEncoder()
} catch (error) {}
let extensions, extensionClasses
const hasNodeBuffer = typeof Buffer !== 'undefined'
const ByteArrayAllocate = hasNodeBuffer ? Buffer.allocUnsafeSlow : Uint8Array
const ByteArray = hasNodeBuffer ? Buffer : Uint8Array
let target
let targetView
let position = 0
let safeEnd
const RECORD_SYMBOL = Symbol('record-id')
class Packr extends Unpackr {
constructor(options) {
super(options)
this.offset = 0
let typeBuffer
let start
let sharedStructures
let hasSharedUpdate
let structures
let referenceMap
let lastSharedStructuresLength = 0
let encodeUtf8 = ByteArray.prototype.utf8Write ? function(string, position, maxBytes) {
return target.utf8Write(string, position, maxBytes)
} : (textEncoder && textEncoder.encodeInto) ?
function(string, position) {
return textEncoder.encodeInto(string, target.subarray(position)).written
} : false
let packr = this
let maxSharedStructures = 32
let isSequential = options && options.sequential
if (isSequential) {
maxSharedStructures = 0
this.structures = []
}
let recordIdsToRemove = []
let transitionsCount = 0
let serializationsSinceTransitionRebuild = 0
if (this.structures && this.structures.length > maxSharedStructures) {
throw new Error('Too many shared structures')
}
this.pack = this.encode = function(value) {
if (!target) {
target = new ByteArrayAllocate(8192)
targetView = new DataView(target.buffer, 0, 8192)
position = 0
}
safeEnd = target.length - 10
if (safeEnd - position < 0x800) {
// don't start too close to the end,
target = new ByteArrayAllocate(target.length)
targetView = new DataView(target.buffer, 0, target.length)
safeEnd = target.length - 10
position = 0
}
start = position
referenceMap = packr.structuredClone ? new Map() : null
sharedStructures = packr.structures
if (sharedStructures) {
if (sharedStructures.uninitialized)
packr.structures = sharedStructures = packr.getStructures()
let sharedStructuresLength = sharedStructures.length
if (sharedStructuresLength > maxSharedStructures && !isSequential)
sharedStructuresLength = maxSharedStructures
if (!sharedStructures.transitions) {
// rebuild our structure transitions
sharedStructures.transitions = Object.create(null)
for (let i = 0; i < sharedStructuresLength; i++) {
let keys = sharedStructures[i]
if (!keys)
continue
let nextTransition, transition = sharedStructures.transitions
for (let i =0, l = keys.length; i < l; i++) {
let key = keys[i]
nextTransition = transition[key]
if (!nextTransition) {
nextTransition = transition[key] = Object.create(null)
}
transition = nextTransition
}
transition[RECORD_SYMBOL] = i + 0x40
}
lastSharedStructuresLength = sharedStructures.length
}
if (!isSequential)
sharedStructures.nextId = sharedStructuresLength + 0x40
}
if (hasSharedUpdate)
hasSharedUpdate = false
structures = sharedStructures || []
try {
pack(value)
packr.offset = position // update the offset so next serialization doesn't write over our buffer, but can continue writing to same buffer sequentially
if (referenceMap && referenceMap.idsToInsert) {
position += referenceMap.idsToInsert.length * 6
if (position > safeEnd)
makeRoom(position)
packr.offset = position
let serialized = insertIds(target.subarray(start, position), referenceMap.idsToInsert)
referenceMap = null
return serialized
}
return target.subarray(start, position) // position can change if we call pack again in saveStructures, so we get the buffer now
} finally {
if (sharedStructures) {
if (serializationsSinceTransitionRebuild < 10)
serializationsSinceTransitionRebuild++
if (transitionsCount > 10000) {
// force a rebuild occasionally after a lot of transitions so it can get cleaned up
sharedStructures.transitions = null
serializationsSinceTransitionRebuild = 0
transitionsCount = 0
if (recordIdsToRemove.length > 0)
recordIdsToRemove = []
} else if (recordIdsToRemove.length > 0 && !isSequential) {
for (let i = 0, l = recordIdsToRemove.length; i < l; i++) {
recordIdsToRemove[i][RECORD_SYMBOL] = 0
}
recordIdsToRemove = []
}
if (hasSharedUpdate && packr.saveStructures) {
if (packr.structures.length > maxSharedStructures) {
packr.structures = packr.structures.slice(0, maxSharedStructures)
}
if (packr.saveStructures(packr.structures, lastSharedStructuresLength) === false) {
// get updated structures and try again if the update failed
packr.structures = packr.getStructures() || []
return packr.pack(value)
}
lastSharedStructuresLength = packr.structures.length
}
}
}
}
const pack = (value) => {
if (position > safeEnd)
target = makeRoom(position)
var type = typeof value
var length
if (type === 'string') {
let strLength = value.length
let headerSize
// first we estimate the header size, so we can write to the correct location
if (strLength < 0x20) {
headerSize = 1
} else if (strLength < 0x100) {
headerSize = 2
} else if (strLength < 0x10000) {
headerSize = 3
} else {
headerSize = 5
}
let maxBytes = strLength * 3
if (position + maxBytes > safeEnd)
target = makeRoom(position + maxBytes)
if (strLength < 0x40 || !encodeUtf8) {
let i, c1, c2, strPosition = position + headerSize
for (i = 0; i < strLength; i++) {
c1 = value.charCodeAt(i)
if (c1 < 0x80) {
target[strPosition++] = c1
} else if (c1 < 0x800) {
target[strPosition++] = c1 >> 6 | 0xc0
target[strPosition++] = c1 & 0x3f | 0x80
} else if (
(c1 & 0xfc00) === 0xd800 &&
((c2 = value.charCodeAt(i + 1)) & 0xfc00) === 0xdc00
) {
c1 = 0x10000 + ((c1 & 0x03ff) << 10) + (c2 & 0x03ff)
i++
target[strPosition++] = c1 >> 18 | 0xf0
target[strPosition++] = c1 >> 12 & 0x3f | 0x80
target[strPosition++] = c1 >> 6 & 0x3f | 0x80
target[strPosition++] = c1 & 0x3f | 0x80
} else {
target[strPosition++] = c1 >> 12 | 0xe0
target[strPosition++] = c1 >> 6 & 0x3f | 0x80
target[strPosition++] = c1 & 0x3f | 0x80
}
}
length = strPosition - position - headerSize
} else {
length = encodeUtf8(value, position + headerSize, maxBytes)
}
if (length < 0x20) {
target[position++] = 0xa0 | length
} else if (length < 0x100) {
if (headerSize < 2) {
target.copyWithin(position + 2, position + 1, position + 1 + length)
}
target[position++] = 0xd9
target[position++] = length
} else if (length < 0x10000) {
if (headerSize < 3) {
target.copyWithin(position + 3, position + 2, position + 2 + length)
}
target[position++] = 0xda
target[position++] = length >> 8
target[position++] = length & 0xff
} else {
if (headerSize < 5) {
target.copyWithin(position + 5, position + 3, position + 3 + length)
}
target[position++] = 0xdb
targetView.setUint32(position, length)
position += 4
}
position += length
} else if (type === 'number') {
if (value >>> 0 === value) {// positive integer, 32-bit or less
// positive uint
if (value < 0x40) {
target[position++] = value
} else if (value < 0x100) {
target[position++] = 0xcc
target[position++] = value
} else if (value < 0x10000) {
target[position++] = 0xcd
target[position++] = value >> 8
target[position++] = value & 0xff
} else {
target[position++] = 0xce
targetView.setUint32(position, value)
position += 4
}
} else if (value >> 0 === value) { // negative integer
if (value >= -0x20) {
target[position++] = 0x100 + value
} else if (value >= -0x80) {
target[position++] = 0xd0
target[position++] = value + 0x100
} else if (value >= -0x8000) {
target[position++] = 0xd1
targetView.setInt16(position, value)
position += 2
} else {
target[position++] = 0xd2
targetView.setInt32(position, value)
position += 4
}
} else {
let useFloat32
if ((useFloat32 = this.useFloat32) > 0 && value < 0x100000000 && value >= -0x80000000) {
target[position++] = 0xca
targetView.setFloat32(position, value)
let xShifted
if (useFloat32 < 4 ||
// this checks for rounding of numbers that were encoded in 32-bit float to nearest significant decimal digit that could be preserved
((xShifted = value * mult10[((target[position] & 0x7f) << 1) | (target[position + 1] >> 7)]) >> 0) === xShifted) {
position += 4
return
} else
position-- // move back into position for writing a double
}
target[position++] = 0xcb
targetView.setFloat64(position, value)
position += 8
}
} else if (type === 'object') {
if (!value)
target[position++] = 0xc0
else {
if (referenceMap) {
let referee = referenceMap.get(value)
if (referee) {
if (!referee.id) {
let idsToInsert = referenceMap.idsToInsert || (referenceMap.idsToInsert = [])
referee.id = idsToInsert.push(referee)
}
target[position++] = 0xd6 // fixext 4
target[position++] = 0x70 // "p" for pointer
targetView.setUint32(position, referee.id)
position += 4
return
} else
referenceMap.set(value, { offset: position - start })
}
let constructor = value.constructor
if (constructor === Object) {
writeObject(value, true)
} else if (constructor === Array) {
length = value.length
if (length < 0x10) {
target[position++] = 0x90 | length
} else if (length < 0x10000) {
target[position++] = 0xdc
target[position++] = length >> 8
target[position++] = length & 0xff
} else {
target[position++] = 0xdd
targetView.setUint32(position, length)
position += 4
}
for (let i = 0; i < length; i++) {
pack(value[i])
}
} else if (constructor === Map) {
length = value.size
if (length < 0x10) {
target[position++] = 0x80 | length
} else if (length < 0x10000) {
target[position++] = 0xde
target[position++] = length >> 8
target[position++] = length & 0xff
} else {
target[position++] = 0xdf
targetView.setUint32(position, length)
position += 4
}
for (let [ key, entryValue ] of value) {
pack(key)
pack(entryValue)
}
} else {
for (let i = 0, l = extensions.length; i < l; i++) {
let extensionClass = extensionClasses[i]
if (value instanceof extensionClass) {
let extension = extensions[i]
let currentTarget = target
let currentTargetView = targetView
let currentPosition = position
target = null
let result
try {
result = extension.pack.call(this, value, (size) => {
// restore target and use it
target = currentTarget
currentTarget = null
position += size
if (position > safeEnd)
makeRoom(position)
return {
target, targetView, position: position - size
}
}, pack)
} finally {
// restore current target information (unless already restored)
if (currentTarget) {
target = currentTarget
targetView = currentTargetView
position = currentPosition
safeEnd = target.length - 10
}
}
if (result) {
position = writeExtensionData(result, target, position, extension.type)
}
return
}
}
// no extension found, write as object
writeObject(value, false)
}
}
} else if (type === 'boolean') {
target[position++] = value ? 0xc3 : 0xc2
} else if (type === 'bigint') {
if (value < (1n<<63n) && value >= -(1n<<63n)) {
// use a signed int as long as it fits
target[position++] = 0xd3
targetView.setBigInt64(position, value)
} else if (value < (1n<<64n) && value > 0) {
// if we can fit an unsigned int, use that
target[position++] = 0xcf
targetView.setBigUint64(position, value)
} else {
// overflow
if (this.largeBigIntToFloat) {
target[position++] = 0xcb
targetView.setFloat64(position, Number(value))
} else {
throw new RangeError(value + ' was too large to fit in MessagePack 64-bit integer format, set largeBigIntToFloat to convert to float-64')
}
}
position += 8
} else if (type === 'undefined') {
//target[position++] = 0xc1 // this is the "never-used" byte
target[position++] = 0xd4 // a number of implementations use fixext1 with type 0, data 0 to denote undefined, so we follow suite
target[position++] = 0
target[position++] = 0
} else {
throw new Error('Unknown type ' + type)
}
}
const writeObject = this.useRecords === false ? this.variableMapSize ? (object) => {
// this method is slightly slower, but generates "preferred serialization" (optimally small for smaller objects)
let keys = Object.keys(object)
let length = keys.length
if (length < 0x10) {
target[position++] = 0x80 | length
} else if (length < 0x10000) {
target[position++] = 0xde
target[position++] = length >> 8
target[position++] = length & 0xff
} else {
target[position++] = 0xdf
targetView.setUint32(position, length)
position += 4
}
let key
for (let i = 0; i < length; i++) {
pack(key = keys[i])
pack(object[key])
}
} :
(object, safePrototype) => {
target[position++] = 0xde // always using map 16, so we can preallocate and set the length afterwards
let objectOffset = position - start
position += 2
let size = 0
for (let key in object) {
if (safePrototype || object.hasOwnProperty(key)) {
pack(key)
pack(object[key])
size++
}
}
target[objectOffset++ + start] = size >> 8
target[objectOffset + start] = size & 0xff
} :
/* sharedStructures ? // For highly stable structures, using for-in can a little bit faster
(object, safePrototype) => {
let nextTransition, transition = structures.transitions || (structures.transitions = Object.create(null))
let objectOffset = position++ - start
let wroteKeys
for (let key in object) {
if (safePrototype || object.hasOwnProperty(key)) {
nextTransition = transition[key]
if (!nextTransition) {
nextTransition = transition[key] = Object.create(null)
nextTransition.__keys__ = (transition.__keys__ || []).concat([key])
/*let keys = Object.keys(object)
if
let size = 0
let startBranch = transition.__keys__ ? transition.__keys__.length : 0
for (let i = 0, l = keys.length; i++) {
let key = keys[i]
size += key.length << 2
if (i >= startBranch) {
nextTransition = nextTransition[key] = Object.create(null)
nextTransition.__keys__ = keys.slice(0, i + 1)
}
}
makeRoom(position + size)
nextTransition = transition[key]
target.copy(target, )
objectOffset
}
transition = nextTransition
pack(object[key])
}
}
let id = transition.id
if (!id) {
id = transition.id = structures.push(transition.__keys__) + 63
if (sharedStructures.onUpdate)
sharedStructures.onUpdate(id, transition.__keys__)
}
target[objectOffset + start] = id
}*/
(object) => {
let keys = Object.keys(object)
let nextTransition, transition = structures.transitions || (structures.transitions = Object.create(null))
let newTransitions = 0
for (let i =0, l = keys.length; i < l; i++) {
let key = keys[i]
nextTransition = transition[key]
if (!nextTransition) {
nextTransition = transition[key] = Object.create(null)
newTransitions++
}
transition = nextTransition
}
let recordId = transition[RECORD_SYMBOL]
if (recordId) {
target[position++] = recordId
} else {
recordId = structures.nextId++
if (!recordId) {
recordId = 0x40
structures.nextId = 0x41
}
if (recordId >= 0x80) {// cycle back around
structures.nextId = (recordId = maxSharedStructures + 0x40) + 1
}
transition[RECORD_SYMBOL] = recordId
structures[0x3f & recordId] = keys
if (sharedStructures && sharedStructures.length <= maxSharedStructures) {
target[position++] = recordId
hasSharedUpdate = true
} else {
target[position++] = 0xd4 // fixext 1
target[position++] = 0x72 // "r" record defintion extension type
target[position++] = recordId
if (newTransitions)
transitionsCount += serializationsSinceTransitionRebuild * newTransitions
// record the removal of the id, we can maintain our shared structure
if (recordIdsToRemove.length >= 0x40 - maxSharedStructures)
recordIdsToRemove.shift()[RECORD_SYMBOL] = 0 // we are cycling back through, and have to remove old ones
recordIdsToRemove.push(transition)
pack(keys)
}
}
// now write the values
for (let i =0, l = keys.length; i < l; i++)
pack(object[keys[i]])
}
const makeRoom = (end) => {
let newSize = ((Math.max((end - start) << 2, target.length - 1) >> 12) + 1) << 12
let newBuffer = new ByteArrayAllocate(newSize)
targetView = new DataView(newBuffer.buffer, 0, newSize)
if (target.copy)
target.copy(newBuffer, 0, start, end)
else
copyBinary(target, newBuffer, 0, start, end)
position -= start
start = 0
safeEnd = newBuffer.length - 10
return target = newBuffer
}
}
useBuffer(buffer) {
// this means we are finished using our own buffer and we can write over it safely
target = buffer
targetView = new DataView(target.buffer, target.byteOffset, target.byteLength)
position = 0
}
}
exports.Packr = Packr
function copyBinary(source, target, targetOffset, offset, endOffset) {
while (offset < endOffset) {
target[targetOffset++] = source[offset++]
}
}
extensionClasses = [ Date, Set, Error, RegExp, ArrayBuffer, Object.getPrototypeOf(Uint8Array.prototype).constructor /*TypedArray*/, C1Type ]
extensions = [{
pack(date, allocateForWrite) {
let seconds = date.getTime() / 1000
if ((this.useTimestamp32 || date.getMilliseconds() === 0) && seconds >= 0 && seconds < 0x100000000) {
// Timestamp 32
let { target, targetView, position} = allocateForWrite(6)
target[position++] = 0xd6
target[position++] = 0xff
targetView.setUint32(position, seconds)
} else if (seconds > 0 && seconds < 0x400000000) {
// Timestamp 64
let { target, targetView, position} = allocateForWrite(10)
target[position++] = 0xd7
target[position++] = 0xff
targetView.setUint32(position, date.getMilliseconds() * 4000000 + ((seconds / 1000 / 0x100000000) >> 0))
targetView.setUint32(position + 4, seconds)
} else {
// Timestamp 96
let { target, targetView, position} = allocateForWrite(15)
target[position++] = 0xc7
target[position++] = 12
target[position++] = 0xff
targetView.setUint32(position, date.getMilliseconds() * 1000000)
targetView.setBigInt64(position + 4, BigInt(Math.floor(seconds)))
}
}
}, {
pack(set, allocateForWrite, pack) {
let array = Array.from(set)
if (this.structuredClone) {
let { target, position} = allocateForWrite(3)
target[position++] = 0xd4
target[position++] = 0x73 // 's' for Set
target[position++] = 0
}
pack(array)
}
}, {
pack(error, allocateForWrite, pack) {
if (this.structuredClone) {
let { target, position} = allocateForWrite(3)
target[position++] = 0xd4
target[position++] = 0x65 // 'e' for error
target[position++] = 0
}
pack([ error.name, error.message ])
}
}, {
pack(regex, allocateForWrite, pack) {
if (this.structuredClone) {
let { target, position} = allocateForWrite(3)
target[position++] = 0xd4
target[position++] = 0x78 // 'x' for regeXp
target[position++] = 0
}
pack([ regex.source, regex.flags ])
}
}, {
pack(arrayBuffer, allocateForWrite) {
if (this.structuredClone)
writeExtBuffer(arrayBuffer, 0x10, allocateForWrite)
else
writeBuffer(hasNodeBuffer ? Buffer.from(arrayBuffer) : new Uint8Array(arrayBuffer), allocateForWrite)
}
}, {
pack(typedArray, allocateForWrite) {
let constructor = typedArray.constructor
if (constructor !== ByteArray && this.structuredClone)
writeExtBuffer(typedArray, typedArrays.indexOf(constructor.name), allocateForWrite)
else
writeBuffer(typedArray, allocateForWrite)
}
}, {
pack(c1, allocateForWrite) { // specific 0xC1 object
let { target, position} = allocateForWrite(1)
target[position] = 0xc1
}
}]
function writeExtBuffer(typedArray, type, allocateForWrite, encode) {
let length = typedArray.byteLength
let offset = typedArray.byteOffset || 0
let buffer = typedArray.buffer || typedArray
if (length + 1 < 0x100) {
var { target, position } = allocateForWrite(4 + length)
target[position++] = 0xc7
target[position++] = length + 1
} else if (length + 1 < 0x10000) {
var { target, position } = allocateForWrite(5 + length)
target[position++] = 0xc8
target[position++] = (length + 1) >> 8
target[position++] = (length + 1) & 0xff
} else {
var { target, position, targetView } = allocateForWrite(7 + length)
target[position++] = 0xc9
targetView.setUint32(position, length + 1) // plus one for the type byte
position += 4
}
target[position++] = 0x74 // "t" for typed array
target[position++] = type
if (hasNodeBuffer)
Buffer.from(buffer, offset, length).copy(target, position)
else
copyBinary(new Uint8Array(buffer, offset, length), target, position, 0, length)
}
function writeBuffer(buffer, allocateForWrite) {
let length = buffer.byteLength
var target, position
if (length < 0x100) {
var { target, position } = allocateForWrite(length + 2)
target[position++] = 0xc4
target[position++] = length
} else if (length < 0x10000) {
var { target, position } = allocateForWrite(length + 3)
target[position++] = 0xc5
target[position++] = length >> 8
target[position++] = length & 0xff
} else {
var { target, position, targetView } = allocateForWrite(length + 5)
target[position++] = 0xc6
targetView.setUint32(position, length)
position += 4
}
if (buffer.copy)
buffer.copy(target, position)
else
copyBinary(buffer, target, position, 0, length)
}
function writeExtensionData(result, target, position, type) {
let length = result.length
switch (length) {
case 1:
target[position++] = 0xd4
break
case 2:
target[position++] = 0xd5
break
case 4:
target[position++] = 0xd6
break
case 8:
target[position++] = 0xd7
break
case 16:
target[position++] = 0xd8
break
default:
if (length < 0x100) {
target[position++] = 0xc7
target[position++] = length
} else if (length < 0x10000) {
target[position++] = 0xc8
target[position++] = length >> 8
target[position++] = length & 0xff
} else {
target[position++] = 0xc9
target[position++] = length >> 24
target[position++] = (length >> 16) & 0xff
target[position++] = (length >> 8) & 0xff
target[position++] = length & 0xff
}
}
target[position++] = type
if (result.copy)
result.copy(target, position)
else
copyBinary(result, target, position, 0, length)
position += length
return position
}
function insertIds(serialized, idsToInsert) {
// insert the ids that need to be referenced for structured clones
let nextId
let distanceToMove = idsToInsert.length * 6
let lastEnd = serialized.length - distanceToMove
idsToInsert.sort((a, b) => a.offset > b.offset ? 1 : -1)
while (nextId = idsToInsert.pop()) {
let offset = nextId.offset
let id = nextId.id
serialized.copyWithin(offset + distanceToMove, offset, lastEnd)
distanceToMove -= 6
let position = offset + distanceToMove
serialized[position++] = 0xd6
serialized[position++] = 0x69 // 'i'
serialized[position++] = id >> 24
serialized[position++] = (id >> 16) & 0xff
serialized[position++] = (id >> 8) & 0xff
serialized[position++] = id & 0xff
lastEnd = offset
}
return serialized
}
exports.addExtension = function(extension) {
if (extension.Class) {
if (!extension.pack)
throw new Error('Extension has no pack function')
extensionClasses.unshift(extension.Class)
extensions.unshift(extension)
}
unpackModule.addExtension(extension)
}
let defaultPackr = new Packr({ useRecords: false })
exports.pack = defaultPackr.pack
exports.encode = defaultPackr.pack
Object.assign(exports, exports.FLOAT32_OPTIONS = unpackModule.FLOAT32_OPTIONS)