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encode.js
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encode.js
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import { Decoder, mult10, Tag, typedArrays, addExtension as decodeAddExtension } from './decode.js'
let textEncoder
try {
textEncoder = new TextEncoder()
} catch (error) {}
let extensions, extensionClasses
const Buffer = typeof globalThis === 'object' && globalThis.Buffer;
const hasNodeBuffer = typeof Buffer !== 'undefined'
const ByteArrayAllocate = hasNodeBuffer ? Buffer.allocUnsafeSlow : Uint8Array
const ByteArray = hasNodeBuffer ? Buffer : Uint8Array
const MAX_STRUCTURES = 0x100
const MAX_BUFFER_SIZE = hasNodeBuffer ? 0x100000000 : 0x7fd00000
let serializationId = 1
let throwOnIterable
let target
let targetView
let position = 0
let safeEnd
let bundledStrings = null
const MAX_BUNDLE_SIZE = 0xf000
const hasNonLatin = /[\u0080-\uFFFF]/
const RECORD_SYMBOL = Symbol('record-id')
export class Encoder extends Decoder {
constructor(options) {
super(options)
this.offset = 0
let typeBuffer
let start
let sharedStructures
let hasSharedUpdate
let structures
let referenceMap
options = options || {}
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 encoder = this
let hasSharedStructures = options.structures || options.saveStructures
let maxSharedStructures = options.maxSharedStructures
if (maxSharedStructures == null)
maxSharedStructures = hasSharedStructures ? 128 : 0
if (maxSharedStructures > 8190)
throw new Error('Maximum maxSharedStructure is 8190')
let isSequential = options.sequential
if (isSequential) {
maxSharedStructures = 0
}
if (!this.structures)
this.structures = []
if (this.saveStructures)
this.saveShared = this.saveStructures
let samplingPackedValues, packedObjectMap, sharedValues = options.sharedValues
let sharedPackedObjectMap
if (sharedValues) {
sharedPackedObjectMap = Object.create(null)
for (let i = 0, l = sharedValues.length; i < l; i++) {
sharedPackedObjectMap[sharedValues[i]] = i
}
}
let recordIdsToRemove = []
let transitionsCount = 0
let serializationsSinceTransitionRebuild = 0
this.mapEncode = function(value, encodeOptions) {
// Experimental support for premapping keys using _keyMap instad of keyMap - not optiimised yet)
if (this._keyMap && !this._mapped) {
//console.log('encoding ', value)
switch (value.constructor.name) {
case 'Array':
value = value.map(r => this.encodeKeys(r))
break
//case 'Map':
// value = this.encodeKeys(value)
// break
}
//this._mapped = true
}
return this.encode(value, encodeOptions)
}
this.encode = function(value, encodeOptions) {
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
} else if (encodeOptions === REUSE_BUFFER_MODE)
position = (position + 7) & 0x7ffffff8 // Word align to make any future copying of this buffer faster
start = position
if (encoder.useSelfDescribedHeader) {
targetView.setUint32(position, 0xd9d9f700) // tag two byte, then self-descriptive tag
position += 3
}
referenceMap = encoder.structuredClone ? new Map() : null
if (encoder.bundleStrings && typeof value !== 'string') {
bundledStrings = []
bundledStrings.size = Infinity // force a new bundle start on first string
} else
bundledStrings = null
sharedStructures = encoder.structures
if (sharedStructures) {
if (sharedStructures.uninitialized) {
let sharedData = encoder.getShared() || {}
encoder.structures = sharedStructures = sharedData.structures || []
encoder.sharedVersion = sharedData.version
let sharedValues = encoder.sharedValues = sharedData.packedValues
if (sharedValues) {
sharedPackedObjectMap = {}
for (let i = 0, l = sharedValues.length; i < l; i++)
sharedPackedObjectMap[sharedValues[i]] = i
}
}
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]
//console.log('shared struct keys:', keys)
if (!keys)
continue
let nextTransition, transition = sharedStructures.transitions
for (let j = 0, l = keys.length; j < l; j++) {
if (transition[RECORD_SYMBOL] === undefined)
transition[RECORD_SYMBOL] = i
let key = keys[j]
nextTransition = transition[key]
if (!nextTransition) {
nextTransition = transition[key] = Object.create(null)
}
transition = nextTransition
}
transition[RECORD_SYMBOL] = i | 0x100000
}
}
if (!isSequential)
sharedStructures.nextId = sharedStructuresLength
}
if (hasSharedUpdate)
hasSharedUpdate = false
structures = sharedStructures || []
packedObjectMap = sharedPackedObjectMap
if (options.pack) {
let packedValues = new Map()
packedValues.values = []
packedValues.encoder = encoder
packedValues.maxValues = options.maxPrivatePackedValues || (sharedPackedObjectMap ? 16 : Infinity)
packedValues.objectMap = sharedPackedObjectMap || false
packedValues.samplingPackedValues = samplingPackedValues
findRepetitiveStrings(value, packedValues)
if (packedValues.values.length > 0) {
target[position++] = 0xd8 // one-byte tag
target[position++] = 51 // tag 51 for packed shared structures https://www.potaroo.net/ietf/ids/draft-ietf-cbor-packed-03.txt
writeArrayHeader(4)
let valuesArray = packedValues.values
encode(valuesArray)
writeArrayHeader(0) // prefixes
writeArrayHeader(0) // suffixes
packedObjectMap = Object.create(sharedPackedObjectMap || null)
for (let i = 0, l = valuesArray.length; i < l; i++) {
packedObjectMap[valuesArray[i]] = i
}
}
}
throwOnIterable = encodeOptions & THROW_ON_ITERABLE;
try {
if (throwOnIterable)
return;
encode(value)
if (bundledStrings) {
writeBundles(start, encode)
}
encoder.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 * 2
if (position > safeEnd)
makeRoom(position)
encoder.offset = position
let serialized = insertIds(target.subarray(start, position), referenceMap.idsToInsert)
referenceMap = null
return serialized
}
if (encodeOptions & REUSE_BUFFER_MODE) {
target.start = start
target.end = position
return target
}
return target.subarray(start, position) // position can change if we call encode again in saveShared, so we get the buffer now
} finally {
if (sharedStructures) {
if (serializationsSinceTransitionRebuild < 10)
serializationsSinceTransitionRebuild++
if (sharedStructures.length > maxSharedStructures)
sharedStructures.length = maxSharedStructures
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] = undefined
}
recordIdsToRemove = []
//sharedStructures.nextId = maxSharedStructures
}
}
if (hasSharedUpdate && encoder.saveShared) {
if (encoder.structures.length > maxSharedStructures) {
encoder.structures = encoder.structures.slice(0, maxSharedStructures)
}
// we can't rely on start/end with REUSE_BUFFER_MODE since they will (probably) change when we save
let returnBuffer = target.subarray(start, position)
if (encoder.updateSharedData() === false)
return encoder.encode(value) // re-encode if it fails
return returnBuffer
}
if (encodeOptions & RESET_BUFFER_MODE)
position = start
}
}
this.findCommonStringsToPack = () => {
samplingPackedValues = new Map()
if (!sharedPackedObjectMap)
sharedPackedObjectMap = Object.create(null)
return (options) => {
let threshold = options && options.threshold || 4
let position = this.pack ? options.maxPrivatePackedValues || 16 : 0
if (!sharedValues)
sharedValues = this.sharedValues = []
for (let [ key, status ] of samplingPackedValues) {
if (status.count > threshold) {
sharedPackedObjectMap[key] = position++
sharedValues.push(key)
hasSharedUpdate = true
}
}
while (this.saveShared && this.updateSharedData() === false) {}
samplingPackedValues = null
}
}
const encode = (value) => {
if (position > safeEnd)
target = makeRoom(position)
var type = typeof value
var length
if (type === 'string') {
if (packedObjectMap) {
let packedPosition = packedObjectMap[value]
if (packedPosition >= 0) {
if (packedPosition < 16)
target[position++] = packedPosition + 0xe0 // simple values, defined in https://www.potaroo.net/ietf/ids/draft-ietf-cbor-packed-03.txt
else {
target[position++] = 0xc6 // tag 6 defined in https://www.potaroo.net/ietf/ids/draft-ietf-cbor-packed-03.txt
if (packedPosition & 1)
encode((15 - packedPosition) >> 1)
else
encode((packedPosition - 16) >> 1)
}
return
/* } else if (packedStatus.serializationId != serializationId) {
packedStatus.serializationId = serializationId
packedStatus.count = 1
if (options.sharedPack) {
let sharedCount = packedStatus.sharedCount = (packedStatus.sharedCount || 0) + 1
if (shareCount > (options.sharedPack.threshold || 5)) {
let sharedPosition = packedStatus.position = packedStatus.nextSharedPosition
hasSharedUpdate = true
if (sharedPosition < 16)
target[position++] = sharedPosition + 0xc0
}
}
} // else any in-doc incrementation?*/
} else if (samplingPackedValues && !options.pack) {
let status = samplingPackedValues.get(value)
if (status)
status.count++
else
samplingPackedValues.set(value, {
count: 1,
})
}
}
let strLength = value.length
if (bundledStrings && strLength >= 4 && strLength < 0x400) {
if ((bundledStrings.size += strLength) > MAX_BUNDLE_SIZE) {
let extStart
let maxBytes = (bundledStrings[0] ? bundledStrings[0].length * 3 + bundledStrings[1].length : 0) + 10
if (position + maxBytes > safeEnd)
target = makeRoom(position + maxBytes)
target[position++] = 0xd9 // tag 16-bit
target[position++] = 0xdf // tag 0xdff9
target[position++] = 0xf9
// TODO: If we only have one bundle with any string data, only write one string bundle
target[position++] = bundledStrings.position ? 0x84 : 0x82 // array of 4 or 2 elements depending on if we write bundles
target[position++] = 0x1a // 32-bit unsigned int
extStart = position - start
position += 4 // reserve for writing bundle reference
if (bundledStrings.position) {
writeBundles(start, encode) // write the last bundles
}
bundledStrings = ['', ''] // create new ones
bundledStrings.size = 0
bundledStrings.position = extStart
}
let twoByte = hasNonLatin.test(value)
bundledStrings[twoByte ? 0 : 1] += value
target[position++] = twoByte ? 0xce : 0xcf
encode(strLength);
return
}
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 < 0x18) {
target[position++] = 0x60 | length
} else if (length < 0x100) {
if (headerSize < 2) {
target.copyWithin(position + 2, position + 1, position + 1 + length)
}
target[position++] = 0x78
target[position++] = length
} else if (length < 0x10000) {
if (headerSize < 3) {
target.copyWithin(position + 3, position + 2, position + 2 + length)
}
target[position++] = 0x79
target[position++] = length >> 8
target[position++] = length & 0xff
} else {
if (headerSize < 5) {
target.copyWithin(position + 5, position + 3, position + 3 + length)
}
target[position++] = 0x7a
targetView.setUint32(position, length)
position += 4
}
position += length
} else if (type === 'number') {
if (!this.alwaysUseFloat && value >>> 0 === value) {// positive integer, 32-bit or less
// positive uint
if (value < 0x18) {
target[position++] = value
} else if (value < 0x100) {
target[position++] = 0x18
target[position++] = value
} else if (value < 0x10000) {
target[position++] = 0x19
target[position++] = value >> 8
target[position++] = value & 0xff
} else {
target[position++] = 0x1a
targetView.setUint32(position, value)
position += 4
}
} else if (!this.alwaysUseFloat && value >> 0 === value) { // negative integer
if (value >= -0x18) {
target[position++] = 0x1f - value
} else if (value >= -0x100) {
target[position++] = 0x38
target[position++] = ~value
} else if (value >= -0x10000) {
target[position++] = 0x39
targetView.setUint16(position, ~value)
position += 2
} else {
target[position++] = 0x3a
targetView.setUint32(position, ~value)
position += 4
}
} else {
let useFloat32
if ((useFloat32 = this.useFloat32) > 0 && value < 0x100000000 && value >= -0x80000000) {
target[position++] = 0xfa
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++] = 0xfb
targetView.setFloat64(position, value)
position += 8
}
} else if (type === 'object') {
if (!value)
target[position++] = 0xf6
else {
if (referenceMap) {
let referee = referenceMap.get(value)
if (referee) {
target[position++] = 0xd8
target[position++] = 29 // http://cbor.schmorp.de/value-sharing
target[position++] = 0x19 // 16-bit uint
if (!referee.references) {
let idsToInsert = referenceMap.idsToInsert || (referenceMap.idsToInsert = [])
referee.references = []
idsToInsert.push(referee)
}
referee.references.push(position - start)
position += 2 // TODO: also support 32-bit
return
} else
referenceMap.set(value, { offset: position - start })
}
let constructor = value.constructor
if (constructor === Object) {
writeObject(value)
} else if (constructor === Array) {
length = value.length
if (length < 0x18) {
target[position++] = 0x80 | length
} else {
writeArrayHeader(length)
}
for (let i = 0; i < length; i++) {
encode(value[i])
}
} else if (constructor === Map) {
if (this.mapsAsObjects ? this.useTag259ForMaps !== false : this.useTag259ForMaps) {
// use Tag 259 (https://github.com/shanewholloway/js-cbor-codec/blob/master/docs/CBOR-259-spec--explicit-maps.md) for maps if the user wants it that way
target[position++] = 0xd9
target[position++] = 1
target[position++] = 3
}
length = value.size
if (length < 0x18) {
target[position++] = 0xa0 | length
} else if (length < 0x100) {
target[position++] = 0xb8
target[position++] = length
} else if (length < 0x10000) {
target[position++] = 0xb9
target[position++] = length >> 8
target[position++] = length & 0xff
} else {
target[position++] = 0xba
targetView.setUint32(position, length)
position += 4
}
if (encoder.keyMap) {
for (let [ key, entryValue ] of value) {
encode(encoder.encodeKey(key))
encode(entryValue)
}
} else {
for (let [ key, entryValue ] of value) {
encode(key)
encode(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 tag = extension.tag
if (tag == undefined)
tag = extension.getTag && extension.getTag.call(this, value)
if (tag < 0x18) {
target[position++] = 0xc0 | tag
} else if (tag < 0x100) {
target[position++] = 0xd8
target[position++] = tag
} else if (tag < 0x10000) {
target[position++] = 0xd9
target[position++] = tag >> 8
target[position++] = tag & 0xff
} else if (tag > -1) {
target[position++] = 0xda
targetView.setUint32(position, tag)
position += 4
} // else undefined, don't write tag
extension.encode.call(this, value, encode, makeRoom)
return
}
}
if (value[Symbol.iterator]) {
if (throwOnIterable) {
let error = new Error('Iterable should be serialized as iterator')
error.iteratorNotHandled = true;
throw error;
}
target[position++] = 0x9f // indefinite length array
for (let entry of value) {
encode(entry)
}
target[position++] = 0xff // stop-code
return
}
if (value[Symbol.asyncIterator] || isBlob(value)) {
let error = new Error('Iterable/blob should be serialized as iterator')
error.iteratorNotHandled = true;
throw error;
}
if (this.useToJSON && value.toJSON) {
const json = value.toJSON()
// if for some reason value.toJSON returns itself it'll loop forever
if (json !== value)
return encode(json)
}
// no extension found, write as a plain object
writeObject(value)
}
}
} else if (type === 'boolean') {
target[position++] = value ? 0xf5 : 0xf4
} else if (type === 'bigint') {
if (value < (BigInt(1)<<BigInt(64)) && value >= 0) {
// use an unsigned int as long as it fits
target[position++] = 0x1b
targetView.setBigUint64(position, value)
} else if (value > -(BigInt(1)<<BigInt(64)) && value < 0) {
// if we can fit an unsigned int, use that
target[position++] = 0x3b
targetView.setBigUint64(position, -value - BigInt(1))
} else {
// overflow
if (this.largeBigIntToFloat) {
target[position++] = 0xfb
targetView.setFloat64(position, Number(value))
} else {
throw new RangeError(value + ' was too large to fit in CBOR 64-bit integer format, set largeBigIntToFloat to convert to float-64')
}
}
position += 8
} else if (type === 'undefined') {
target[position++] = 0xf7
} 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 vals = Object.values(object)
let length = keys.length
if (length < 0x18) {
target[position++] = 0xa0 | length
} else if (length < 0x100) {
target[position++] = 0xb8
target[position++] = length
} else if (length < 0x10000) {
target[position++] = 0xb9
target[position++] = length >> 8
target[position++] = length & 0xff
} else {
target[position++] = 0xba
targetView.setUint32(position, length)
position += 4
}
let key
if (encoder.keyMap) {
for (let i = 0; i < length; i++) {
encode(encoder.encodeKey(keys[i]))
encode(vals[i])
}
} else {
for (let i = 0; i < length; i++) {
encode(keys[i])
encode(vals[i])
}
}
} :
(object) => {
target[position++] = 0xb9 // always use map 16, so we can preallocate and set the length afterwards
let objectOffset = position - start
position += 2
let size = 0
if (encoder.keyMap) {
for (let key in object) if (typeof object.hasOwnProperty !== 'function' || object.hasOwnProperty(key)) {
encode(encoder.encodeKey(key))
encode(object[key])
size++
}
} else {
for (let key in object) if (typeof object.hasOwnProperty !== 'function' || object.hasOwnProperty(key)) {
encode(key)
encode(object[key])
size++
}
}
target[objectOffset++ + start] = size >> 8
target[objectOffset + start] = size & 0xff
} :
(object, skipValues) => {
let nextTransition, transition = structures.transitions || (structures.transitions = Object.create(null))
let newTransitions = 0
let length = 0
let parentRecordId
let keys
if (this.keyMap) {
keys = Object.keys(object).map(k => this.encodeKey(k))
length = keys.length
for (let i = 0; i < length; i++) {
let key = keys[i]
nextTransition = transition[key]
if (!nextTransition) {
nextTransition = transition[key] = Object.create(null)
newTransitions++
}
transition = nextTransition
}
} else {
for (let key in object) if (typeof object.hasOwnProperty !== 'function' || object.hasOwnProperty(key)) {
nextTransition = transition[key]
if (!nextTransition) {
if (transition[RECORD_SYMBOL] & 0x100000) {// this indicates it is a brancheable/extendable terminal node, so we will use this record id and extend it
parentRecordId = transition[RECORD_SYMBOL] & 0xffff
}
nextTransition = transition[key] = Object.create(null)
newTransitions++
}
transition = nextTransition
length++
}
}
let recordId = transition[RECORD_SYMBOL]
if (recordId !== undefined) {
recordId &= 0xffff
target[position++] = 0xd9
target[position++] = (recordId >> 8) | 0xe0
target[position++] = recordId & 0xff
} else {
if (!keys)
keys = transition.__keys__ || (transition.__keys__ = Object.keys(object))
if (parentRecordId === undefined) {
recordId = structures.nextId++
if (!recordId) {
recordId = 0
structures.nextId = 1
}
if (recordId >= MAX_STRUCTURES) {// cycle back around
structures.nextId = (recordId = maxSharedStructures) + 1
}
} else {
recordId = parentRecordId
}
structures[recordId] = keys
if (recordId < maxSharedStructures) {
target[position++] = 0xd9
target[position++] = (recordId >> 8) | 0xe0
target[position++] = recordId & 0xff
transition = structures.transitions
for (let i = 0; i < length; i++) {
if (transition[RECORD_SYMBOL] === undefined || (transition[RECORD_SYMBOL] & 0x100000))
transition[RECORD_SYMBOL] = recordId
transition = transition[keys[i]]
}
transition[RECORD_SYMBOL] = recordId | 0x100000 // indicates it is a extendable terminal
hasSharedUpdate = true
} else {
transition[RECORD_SYMBOL] = recordId
targetView.setUint32(position, 0xd9dfff00) // tag two byte, then record definition id
position += 3
if (newTransitions)
transitionsCount += serializationsSinceTransitionRebuild * newTransitions
// record the removal of the id, we can maintain our shared structure
if (recordIdsToRemove.length >= MAX_STRUCTURES - maxSharedStructures)
recordIdsToRemove.shift()[RECORD_SYMBOL] = undefined // we are cycling back through, and have to remove old ones
recordIdsToRemove.push(transition)
writeArrayHeader(length + 2)
encode(0xe000 + recordId)
encode(keys)
if (skipValues) return; // special exit for iterator
for (let key in object)
if (typeof object.hasOwnProperty !== 'function' || object.hasOwnProperty(key))
encode(object[key])
return
}
}
if (length < 0x18) { // write the array header
target[position++] = 0x80 | length
} else {
writeArrayHeader(length)
}
if (skipValues) return; // special exit for iterator
for (let key in object)
if (typeof object.hasOwnProperty !== 'function' || object.hasOwnProperty(key))
encode(object[key])
}
const makeRoom = (end) => {
let newSize
if (end > 0x1000000) {
// special handling for really large buffers
if ((end - start) > MAX_BUFFER_SIZE)
throw new Error('Encoded buffer would be larger than maximum buffer size')
newSize = Math.min(MAX_BUFFER_SIZE,
Math.round(Math.max((end - start) * (end > 0x4000000 ? 1.25 : 2), 0x400000) / 0x1000) * 0x1000)
} else // faster handling for smaller buffers
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
newBuffer.set(target.slice(start, end))
position -= start
start = 0
safeEnd = newBuffer.length - 10
return target = newBuffer
}
let chunkThreshold = 100;
let continuedChunkThreshold = 1000;
this.encodeAsIterable = function(value, options) {
return startEncoding(value, options, encodeObjectAsIterable);
}
this.encodeAsAsyncIterable = function(value, options) {
return startEncoding(value, options, encodeObjectAsAsyncIterable);
}
function* encodeObjectAsIterable(object, iterateProperties, finalIterable) {
let constructor = object.constructor;
if (constructor === Object) {
let useRecords = encoder.useRecords !== false;
if (useRecords)
writeObject(object, true); // write the record identifier
else
writeEntityLength(Object.keys(object).length, 0xa0);
for (let key in object) {
let value = object[key];
if (!useRecords) encode(key);
if (value && typeof value === 'object') {
if (iterateProperties[key])
yield* encodeObjectAsIterable(value, iterateProperties[key]);
else
yield* tryEncode(value, iterateProperties, key);
} else encode(value);
}
} else if (constructor === Array) {
let length = object.length;
writeArrayHeader(length);
for (let i = 0; i < length; i++) {
let value = object[i];
if (value && (typeof value === 'object' || position - start > chunkThreshold)) {
if (iterateProperties.element)
yield* encodeObjectAsIterable(value, iterateProperties.element);
else
yield* tryEncode(value, iterateProperties, 'element');
} else encode(value);
}
} else if (object[Symbol.iterator]) {
target[position++] = 0x9f; // start indefinite array
for (let value of object) {
if (value && (typeof value === 'object' || position - start > chunkThreshold)) {
if (iterateProperties.element)
yield* encodeObjectAsIterable(value, iterateProperties.element);
else
yield* tryEncode(value, iterateProperties, 'element');
} else encode(value);
}
target[position++] = 0xff; // stop byte
} else if (isBlob(object)){
writeEntityLength(object.size, 0x40); // encode as binary data
yield target.subarray(start, position);
yield object; // directly return blobs, they have to be encoded asynchronously
restartEncoding();
} else if (object[Symbol.asyncIterator]) {
target[position++] = 0x9f; // start indefinite array
yield target.subarray(start, position);
yield object; // directly return async iterators, they have to be encoded asynchronously
restartEncoding();
target[position++] = 0xff; // stop byte
} else {
encode(object);
}
if (finalIterable && position > start) yield target.subarray(start, position);
else if (position - start > chunkThreshold) {
yield target.subarray(start, position);
restartEncoding();
}
}
function* tryEncode(value, iterateProperties, key) {
let restart = position - start;
try {
encode(value);
if (position - start > chunkThreshold) {
yield target.subarray(start, position);
restartEncoding();
}
} catch (error) {
if (error.iteratorNotHandled) {
iterateProperties[key] = {};
position = start + restart; // restart our position so we don't have partial data from last encode
yield* encodeObjectAsIterable.call(this, value, iterateProperties[key]);
} else throw error;
}
}
function restartEncoding() {
chunkThreshold = continuedChunkThreshold;
encoder.encode(null, THROW_ON_ITERABLE); // restart encoding
}
function startEncoding(value, options, encodeIterable) {
if (options && options.chunkThreshold) // explicitly specified chunk sizes
chunkThreshold = continuedChunkThreshold = options.chunkThreshold;
else // we start with a smaller threshold to get initial bytes sent quickly
chunkThreshold = 100;
if (value && typeof value === 'object') {
encoder.encode(null, THROW_ON_ITERABLE); // start encoding
return encodeIterable(value, encoder.iterateProperties || (encoder.iterateProperties = {}), true);
}
return [encoder.encode(value)];
}
async function* encodeObjectAsAsyncIterable(value, iterateProperties) {
for (let encodedValue of encodeObjectAsIterable(value, iterateProperties, true)) {
let constructor = encodedValue.constructor;
if (constructor === ByteArray || constructor === Uint8Array)
yield encodedValue;
else if (isBlob(encodedValue)) {
let reader = encodedValue.stream().getReader();
let next;
while (!(next = await reader.read()).done) {
yield next.value;
}
} else if (encodedValue[Symbol.asyncIterator]) {
for await (let asyncValue of encodedValue) {
restartEncoding();
if (asyncValue)
yield* encodeObjectAsAsyncIterable(asyncValue, iterateProperties.async || (iterateProperties.async = {}));
else yield encoder.encode(asyncValue);
}
} else {
yield encodedValue;
}
}
}
}
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
}
clearSharedData() {
if (this.structures)
this.structures = []
if (this.sharedValues)
this.sharedValues = undefined
}
updateSharedData() {
let lastVersion = this.sharedVersion || 0
this.sharedVersion = lastVersion + 1
let structuresCopy = this.structures.slice(0)
let sharedData = new SharedData(structuresCopy, this.sharedValues, this.sharedVersion)
let saveResults = this.saveShared(sharedData,
existingShared => (existingShared && existingShared.version || 0) == lastVersion)
if (saveResults === false) {
// get updated structures and try again if the update failed
sharedData = this.getShared() || {}
this.structures = sharedData.structures || []
this.sharedValues = sharedData.packedValues
this.sharedVersion = sharedData.version
this.structures.nextId = this.structures.length
} else {
// restore structures
structuresCopy.forEach((structure, i) => this.structures[i] = structure)
}
// saveShared may fail to write and reload, or may have reloaded to check compatibility and overwrite saved data, either way load the correct shared data
return saveResults
}
}
function writeEntityLength(length, majorValue) {
if (length < 0x18)
target[position++] = majorValue | length
else if (length < 0x100) {
target[position++] = majorValue | 0x18
target[position++] = length
} else if (length < 0x10000) {
target[position++] = majorValue | 0x19
target[position++] = length >> 8
target[position++] = length & 0xff
} else {
target[position++] = majorValue | 0x1a
targetView.setUint32(position, length)
position += 4
}
}
class SharedData {
constructor(structures, values, version) {
this.structures = structures
this.packedValues = values
this.version = version
}
}
function writeArrayHeader(length) {
if (length < 0x18)
target[position++] = 0x80 | length
else if (length < 0x100) {
target[position++] = 0x98
target[position++] = length
} else if (length < 0x10000) {
target[position++] = 0x99
target[position++] = length >> 8
target[position++] = length & 0xff
} else {
target[position++] = 0x9a
targetView.setUint32(position, length)
position += 4
}
}
const BlobConstructor = typeof Blob === 'undefined' ? function(){} : Blob;
function isBlob(object) {
if (object instanceof BlobConstructor)
return true;
let tag = object[Symbol.toStringTag];
return tag === 'Blob' || tag === 'File';
}
function findRepetitiveStrings(value, packedValues) {
switch(typeof value) {
case 'string':
if (value.length > 3) {
if (packedValues.objectMap[value] > -1 || packedValues.values.length >= packedValues.maxValues)
return
let packedStatus = packedValues.get(value)
if (packedStatus) {
if (++packedStatus.count == 2) {
packedValues.values.push(value)
}
} else {
packedValues.set(value, {
count: 1,
})
if (packedValues.samplingPackedValues) {
let status = packedValues.samplingPackedValues.get(value)
if (status)
status.count++
else
packedValues.samplingPackedValues.set(value, {
count: 1,
})