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BinaryMiddleware.js
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Thu, Feb 13, 18:59

BinaryMiddleware.js
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/*
MIT License http://www.opensource.org/licenses/mit-license.php
*/
"use strict";
const memorize = require("../util/memorize");
const SerializerMiddleware = require("./SerializerMiddleware");
/** @typedef {import("./types").BufferSerializableType} BufferSerializableType */
/** @typedef {import("./types").PrimitiveSerializableType} PrimitiveSerializableType */
/* eslint-disable no-loop-func */
/*
Format:
File -> Section*
Section -> NullsSection |
BooleansSection |
F64NumbersSection |
I32NumbersSection |
I8NumbersSection |
ShortStringSection |
StringSection |
BufferSection |
NopSection
NullsSection ->
NullHeaderByte | Null2HeaderByte | Null3HeaderByte |
Nulls8HeaderByte 0xnn (n:count - 4) |
Nulls32HeaderByte n:ui32 (n:count - 260) |
BooleansSection -> TrueHeaderByte | FalseHeaderByte | BooleansSectionHeaderByte BooleansCountAndBitsByte
F64NumbersSection -> F64NumbersSectionHeaderByte f64*
I32NumbersSection -> I32NumbersSectionHeaderByte i32*
I8NumbersSection -> I8NumbersSectionHeaderByte i8*
ShortStringSection -> ShortStringSectionHeaderByte ascii-byte*
StringSection -> StringSectionHeaderByte i32:length utf8-byte*
BufferSection -> BufferSectionHeaderByte i32:length byte*
NopSection --> NopSectionHeaderByte
ShortStringSectionHeaderByte -> 0b1nnn_nnnn (n:length)
F64NumbersSectionHeaderByte -> 0b001n_nnnn (n:count - 1)
I32NumbersSectionHeaderByte -> 0b010n_nnnn (n:count - 1)
I8NumbersSectionHeaderByte -> 0b011n_nnnn (n:count - 1)
NullsSectionHeaderByte -> 0b0001_nnnn (n:count - 1)
BooleansCountAndBitsByte ->
0b0000_1xxx (count = 3) |
0b0001_xxxx (count = 4) |
0b001x_xxxx (count = 5) |
0b01xx_xxxx (count = 6) |
0b1nnn_nnnn (n:count - 7, 7 <= count <= 133)
0xff n:ui32 (n:count, 134 <= count < 2^32)
StringSectionHeaderByte -> 0b0000_1110
BufferSectionHeaderByte -> 0b0000_1111
NopSectionHeaderByte -> 0b0000_1011
FalseHeaderByte -> 0b0000_1100
TrueHeaderByte -> 0b0000_1101
RawNumber -> n (n <= 10)
*/
const LAZY_HEADER = 0x0b;
const TRUE_HEADER = 0x0c;
const FALSE_HEADER = 0x0d;
const BOOLEANS_HEADER = 0x0e;
const NULL_HEADER = 0x10;
const NULL2_HEADER = 0x11;
const NULL3_HEADER = 0x12;
const NULLS8_HEADER = 0x13;
const NULLS32_HEADER = 0x14;
const NULL_AND_I8_HEADER = 0x15;
const NULL_AND_I32_HEADER = 0x16;
const NULL_AND_TRUE_HEADER = 0x17;
const NULL_AND_FALSE_HEADER = 0x18;
const STRING_HEADER = 0x1e;
const BUFFER_HEADER = 0x1f;
const I8_HEADER = 0x60;
const I32_HEADER = 0x40;
const F64_HEADER = 0x20;
const SHORT_STRING_HEADER = 0x80;
/** Uplift high-order bits */
const NUMBERS_HEADER_MASK = 0xe0;
const NUMBERS_COUNT_MASK = 0x1f; // 0b0001_1111
const SHORT_STRING_LENGTH_MASK = 0x7f; // 0b0111_1111
const HEADER_SIZE = 1;
const I8_SIZE = 1;
const I32_SIZE = 4;
const F64_SIZE = 8;
const MEASURE_START_OPERATION = Symbol("MEASURE_START_OPERATION");
const MEASURE_END_OPERATION = Symbol("MEASURE_END_OPERATION");
const identifyNumber = n => {
if (n === (n | 0)) {
if (n <= 127 && n >= -128) return 0;
if (n <= 2147483647 && n >= -2147483648) return 1;
}
return 2;
};
/**
* @typedef {PrimitiveSerializableType[]} DeserializedType
* @typedef {BufferSerializableType[]} SerializedType
* @extends {SerializerMiddleware<DeserializedType, SerializedType>}
*/
class BinaryMiddleware extends SerializerMiddleware {
static optimizeSerializedData(data) {
const result = [];
const temp = [];
const flush = () => {
if (temp.length > 0) {
if (temp.length === 1) {
result.push(temp[0]);
} else {
result.push(Buffer.concat(temp));
}
temp.length = 0;
}
};
for (const item of data) {
if (Buffer.isBuffer(item)) {
temp.push(item);
} else {
flush();
result.push(item);
}
}
flush();
return result;
}
/**
* @param {DeserializedType} data data
* @param {Object} context context object
* @returns {SerializedType|Promise<SerializedType>} serialized data
*/
serialize(data, context) {
return this._serialize(data, context);
}
/**
* @param {DeserializedType} data data
* @param {Object} context context object
* @returns {SerializedType} serialized data
*/
_serialize(data, context) {
/** @type {Buffer} */
let currentBuffer = null;
/** @type {Buffer} */
let leftOverBuffer = null;
let currentPosition = 0;
/** @type {BufferSerializableType[]} */
const buffers = [];
let buffersTotalLength = 0;
const allocate = (bytesNeeded, exact = false) => {
if (currentBuffer !== null) {
if (currentBuffer.length - currentPosition >= bytesNeeded) return;
flush();
}
if (leftOverBuffer && leftOverBuffer.length >= bytesNeeded) {
currentBuffer = leftOverBuffer;
leftOverBuffer = null;
} else {
currentBuffer = Buffer.allocUnsafe(
exact ? bytesNeeded : Math.max(bytesNeeded, buffersTotalLength, 1024)
);
}
};
const flush = () => {
if (currentBuffer !== null) {
buffers.push(currentBuffer.slice(0, currentPosition));
if (
!leftOverBuffer ||
leftOverBuffer.length < currentBuffer.length - currentPosition
)
leftOverBuffer = currentBuffer.slice(currentPosition);
currentBuffer = null;
buffersTotalLength += currentPosition;
currentPosition = 0;
}
};
const writeU8 = byte => {
currentBuffer.writeUInt8(byte, currentPosition++);
};
const writeU32 = ui32 => {
currentBuffer.writeUInt32LE(ui32, currentPosition);
currentPosition += 4;
};
const measureStack = [];
const measureStart = () => {
measureStack.push(buffers.length, currentPosition);
};
const measureEnd = () => {
const oldPos = measureStack.pop();
const buffersIndex = measureStack.pop();
let size = currentPosition - oldPos;
for (let i = buffersIndex; i < buffers.length; i++) {
size += buffers[i].length;
}
return size;
};
const serializeData = data => {
for (let i = 0; i < data.length; i++) {
const thing = data[i];
switch (typeof thing) {
case "function": {
if (!SerializerMiddleware.isLazy(thing))
throw new Error("Unexpected function " + thing);
/** @type {SerializedType | (() => SerializedType)} */
let serializedData = SerializerMiddleware.getLazySerializedValue(
thing
);
if (serializedData === undefined) {
if (SerializerMiddleware.isLazy(thing, this)) {
const data = this._serialize(thing(), context);
SerializerMiddleware.setLazySerializedValue(thing, data);
serializedData = data;
} else {
serializedData = SerializerMiddleware.serializeLazy(
thing,
data => this._serialize(data, context)
);
}
}
if (typeof serializedData === "function") {
flush();
buffers.push(serializedData);
} else {
const lengths = [];
for (const item of serializedData) {
let last;
if (typeof item === "function") {
lengths.push(0);
} else if (item.length === 0) {
// ignore
} else if (
lengths.length > 0 &&
(last = lengths[lengths.length - 1]) !== 0
) {
const remaining = 0xffffffff - last;
if (remaining >= item.length) {
lengths[lengths.length - 1] += item.length;
} else {
lengths.push(item.length - remaining);
lengths[lengths.length - 2] = 0xffffffff;
}
} else {
lengths.push(item.length);
}
}
allocate(5 + lengths.length * 4);
writeU8(LAZY_HEADER);
writeU32(lengths.length);
for (const l of lengths) {
writeU32(l);
}
for (const item of serializedData) {
flush();
buffers.push(item);
}
}
break;
}
case "string": {
const len = Buffer.byteLength(thing);
if (len >= 128 || len !== thing.length) {
allocate(len + HEADER_SIZE + I32_SIZE);
writeU8(STRING_HEADER);
writeU32(len);
currentBuffer.write(thing, currentPosition);
} else {
allocate(len + HEADER_SIZE);
writeU8(SHORT_STRING_HEADER | len);
currentBuffer.write(thing, currentPosition, "latin1");
}
currentPosition += len;
break;
}
case "number": {
const type = identifyNumber(thing);
if (type === 0 && thing >= 0 && thing <= 10) {
// shortcut for very small numbers
allocate(I8_SIZE);
writeU8(thing);
break;
}
/**
* amount of numbers to write
* @type {number}
*/
let n = 1;
for (; n < 32 && i + n < data.length; n++) {
const item = data[i + n];
if (typeof item !== "number") break;
if (identifyNumber(item) !== type) break;
}
switch (type) {
case 0:
allocate(HEADER_SIZE + I8_SIZE * n);
writeU8(I8_HEADER | (n - 1));
while (n > 0) {
currentBuffer.writeInt8(
/** @type {number} */ (data[i]),
currentPosition
);
currentPosition += I8_SIZE;
n--;
i++;
}
break;
case 1:
allocate(HEADER_SIZE + I32_SIZE * n);
writeU8(I32_HEADER | (n - 1));
while (n > 0) {
currentBuffer.writeInt32LE(
/** @type {number} */ (data[i]),
currentPosition
);
currentPosition += I32_SIZE;
n--;
i++;
}
break;
case 2:
allocate(HEADER_SIZE + F64_SIZE * n);
writeU8(F64_HEADER | (n - 1));
while (n > 0) {
currentBuffer.writeDoubleLE(
/** @type {number} */ (data[i]),
currentPosition
);
currentPosition += F64_SIZE;
n--;
i++;
}
break;
}
i--;
break;
}
case "boolean": {
let lastByte = thing === true ? 1 : 0;
const bytes = [];
let count = 1;
let n;
for (n = 1; n < 0xffffffff && i + n < data.length; n++) {
const item = data[i + n];
if (typeof item !== "boolean") break;
const pos = count & 0x7;
if (pos === 0) {
bytes.push(lastByte);
lastByte = item === true ? 1 : 0;
} else if (item === true) {
lastByte |= 1 << pos;
}
count++;
}
i += count - 1;
if (count === 1) {
allocate(HEADER_SIZE);
writeU8(lastByte === 1 ? TRUE_HEADER : FALSE_HEADER);
} else if (count === 2) {
allocate(HEADER_SIZE * 2);
writeU8(lastByte & 1 ? TRUE_HEADER : FALSE_HEADER);
writeU8(lastByte & 2 ? TRUE_HEADER : FALSE_HEADER);
} else if (count <= 6) {
allocate(HEADER_SIZE + I8_SIZE);
writeU8(BOOLEANS_HEADER);
writeU8((1 << count) | lastByte);
} else if (count <= 133) {
allocate(HEADER_SIZE + I8_SIZE * bytes.length + I8_SIZE);
writeU8(BOOLEANS_HEADER);
writeU8(0x80 | (count - 7));
for (const byte of bytes) writeU8(byte);
writeU8(lastByte);
} else {
allocate(HEADER_SIZE + I8_SIZE * bytes.length + I8_SIZE);
writeU8(BOOLEANS_HEADER);
writeU8(0xff);
writeU32(count);
for (const byte of bytes) writeU8(byte);
writeU8(lastByte);
}
break;
}
case "object": {
if (thing === null) {
let n;
for (n = 1; n < 0x100000104 && i + n < data.length; n++) {
const item = data[i + n];
if (item !== null) break;
}
i += n - 1;
if (n === 1) {
if (i + 1 < data.length) {
const next = data[i + 1];
if (next === true) {
allocate(HEADER_SIZE);
writeU8(NULL_AND_TRUE_HEADER);
i++;
} else if (next === false) {
allocate(HEADER_SIZE);
writeU8(NULL_AND_FALSE_HEADER);
i++;
} else if (typeof next === "number") {
const type = identifyNumber(next);
if (type === 0) {
allocate(HEADER_SIZE + I8_SIZE);
writeU8(NULL_AND_I8_HEADER);
currentBuffer.writeInt8(next, currentPosition);
currentPosition += I8_SIZE;
i++;
} else if (type === 1) {
allocate(HEADER_SIZE + I32_SIZE);
writeU8(NULL_AND_I32_HEADER);
currentBuffer.writeInt32LE(next, currentPosition);
currentPosition += I32_SIZE;
i++;
} else {
allocate(HEADER_SIZE);
writeU8(NULL_HEADER);
}
} else {
allocate(HEADER_SIZE);
writeU8(NULL_HEADER);
}
} else {
allocate(HEADER_SIZE);
writeU8(NULL_HEADER);
}
} else if (n === 2) {
allocate(HEADER_SIZE);
writeU8(NULL2_HEADER);
} else if (n === 3) {
allocate(HEADER_SIZE);
writeU8(NULL3_HEADER);
} else if (n < 260) {
allocate(HEADER_SIZE + I8_SIZE);
writeU8(NULLS8_HEADER);
writeU8(n - 4);
} else {
allocate(HEADER_SIZE + I32_SIZE);
writeU8(NULLS32_HEADER);
writeU32(n - 260);
}
} else if (Buffer.isBuffer(thing)) {
allocate(HEADER_SIZE + I32_SIZE, true);
writeU8(BUFFER_HEADER);
writeU32(thing.length);
flush();
buffers.push(thing);
}
break;
}
case "symbol": {
if (thing === MEASURE_START_OPERATION) {
measureStart();
} else if (thing === MEASURE_END_OPERATION) {
const size = measureEnd();
allocate(HEADER_SIZE + I32_SIZE);
writeU8(I32_HEADER);
currentBuffer.writeInt32LE(size, currentPosition);
currentPosition += I32_SIZE;
}
break;
}
}
}
};
serializeData(data);
flush();
return buffers;
}
/**
* @param {SerializedType} data data
* @param {Object} context context object
* @returns {DeserializedType|Promise<DeserializedType>} deserialized data
*/
deserialize(data, context) {
return this._deserialize(data, context);
}
/**
* @param {SerializedType} data data
* @param {Object} context context object
* @returns {DeserializedType} deserialized data
*/
_deserialize(data, context) {
let currentDataItem = 0;
let currentBuffer = data[0];
let currentIsBuffer = Buffer.isBuffer(currentBuffer);
let currentPosition = 0;
const checkOverflow = () => {
if (currentPosition >= currentBuffer.length) {
currentPosition = 0;
currentDataItem++;
currentBuffer =
currentDataItem < data.length ? data[currentDataItem] : null;
currentIsBuffer = Buffer.isBuffer(currentBuffer);
}
};
const isInCurrentBuffer = n => {
return currentIsBuffer && n + currentPosition <= currentBuffer.length;
};
/**
* Reads n bytes
* @param {number} n amount of bytes to read
* @returns {Buffer} buffer with bytes
*/
const read = n => {
if (!currentIsBuffer) {
throw new Error(
currentBuffer === null
? "Unexpected end of stream"
: "Unexpected lazy element in stream"
);
}
const rem = currentBuffer.length - currentPosition;
if (rem < n) {
return Buffer.concat([read(rem), read(n - rem)]);
}
const res = /** @type {Buffer} */ (currentBuffer).slice(
currentPosition,
currentPosition + n
);
currentPosition += n;
checkOverflow();
return res;
};
/**
* Reads up to n bytes
* @param {number} n amount of bytes to read
* @returns {Buffer} buffer with bytes
*/
const readUpTo = n => {
if (!currentIsBuffer) {
throw new Error(
currentBuffer === null
? "Unexpected end of stream"
: "Unexpected lazy element in stream"
);
}
const rem = currentBuffer.length - currentPosition;
if (rem < n) {
n = rem;
}
const res = /** @type {Buffer} */ (currentBuffer).slice(
currentPosition,
currentPosition + n
);
currentPosition += n;
checkOverflow();
return res;
};
const readU8 = () => {
if (!currentIsBuffer) {
throw new Error(
currentBuffer === null
? "Unexpected end of stream"
: "Unexpected lazy element in stream"
);
}
/**
* There is no need to check remaining buffer size here
* since {@link checkOverflow} guarantees at least one byte remaining
*/
const byte = /** @type {Buffer} */ (currentBuffer).readUInt8(
currentPosition
);
currentPosition += I8_SIZE;
checkOverflow();
return byte;
};
const readU32 = () => {
return read(I32_SIZE).readUInt32LE(0);
};
const readBits = (data, n) => {
let mask = 1;
while (n !== 0) {
result.push((data & mask) !== 0);
mask = mask << 1;
n--;
}
};
const dispatchTable = Array.from({ length: 256 }).map((_, header) => {
switch (header) {
case LAZY_HEADER:
return () => {
const count = readU32();
const lengths = Array.from({ length: count }).map(() => readU32());
const content = [];
for (let l of lengths) {
if (l === 0) {
if (typeof currentBuffer !== "function") {
throw new Error("Unexpected non-lazy element in stream");
}
content.push(currentBuffer);
currentDataItem++;
currentBuffer =
currentDataItem < data.length ? data[currentDataItem] : null;
currentIsBuffer = Buffer.isBuffer(currentBuffer);
} else {
do {
const buf = readUpTo(l);
l -= buf.length;
content.push(buf);
} while (l > 0);
}
}
result.push(
SerializerMiddleware.createLazy(
memorize(() => this._deserialize(content, context)),
this,
undefined,
content
)
);
};
case BUFFER_HEADER:
return () => {
const len = readU32();
result.push(read(len));
};
case TRUE_HEADER:
return () => result.push(true);
case FALSE_HEADER:
return () => result.push(false);
case NULL3_HEADER:
return () => result.push(null, null, null);
case NULL2_HEADER:
return () => result.push(null, null);
case NULL_HEADER:
return () => result.push(null);
case NULL_AND_TRUE_HEADER:
return () => result.push(null, true);
case NULL_AND_FALSE_HEADER:
return () => result.push(null, false);
case NULL_AND_I8_HEADER:
return () => {
if (currentIsBuffer) {
result.push(
null,
/** @type {Buffer} */ (currentBuffer).readInt8(currentPosition)
);
currentPosition += I8_SIZE;
checkOverflow();
} else {
result.push(null, read(I8_SIZE).readInt8(0));
}
};
case NULL_AND_I32_HEADER:
return () => {
result.push(null);
if (isInCurrentBuffer(I32_SIZE)) {
result.push(
/** @type {Buffer} */ (currentBuffer).readInt32LE(
currentPosition
)
);
currentPosition += I32_SIZE;
checkOverflow();
} else {
result.push(read(I32_SIZE).readInt32LE(0));
}
};
case NULLS8_HEADER:
return () => {
const len = readU8() + 4;
for (let i = 0; i < len; i++) {
result.push(null);
}
};
case NULLS32_HEADER:
return () => {
const len = readU32() + 260;
for (let i = 0; i < len; i++) {
result.push(null);
}
};
case BOOLEANS_HEADER:
return () => {
const innerHeader = readU8();
if ((innerHeader & 0xf0) === 0) {
readBits(innerHeader, 3);
} else if ((innerHeader & 0xe0) === 0) {
readBits(innerHeader, 4);
} else if ((innerHeader & 0xc0) === 0) {
readBits(innerHeader, 5);
} else if ((innerHeader & 0x80) === 0) {
readBits(innerHeader, 6);
} else if (innerHeader !== 0xff) {
let count = (innerHeader & 0x7f) + 7;
while (count > 8) {
readBits(readU8(), 8);
count -= 8;
}
readBits(readU8(), count);
} else {
let count = readU32();
while (count > 8) {
readBits(readU8(), 8);
count -= 8;
}
readBits(readU8(), count);
}
};
case STRING_HEADER:
return () => {
const len = readU32();
if (isInCurrentBuffer(len)) {
result.push(
currentBuffer.toString(
undefined,
currentPosition,
currentPosition + len
)
);
currentPosition += len;
checkOverflow();
} else {
result.push(read(len).toString());
}
};
case SHORT_STRING_HEADER:
return () => result.push("");
case SHORT_STRING_HEADER | 1:
return () => {
if (currentIsBuffer) {
result.push(
currentBuffer.toString(
"latin1",
currentPosition,
currentPosition + 1
)
);
currentPosition++;
checkOverflow();
} else {
result.push(read(1).toString("latin1"));
}
};
case I8_HEADER:
return () => {
if (currentIsBuffer) {
result.push(
/** @type {Buffer} */ (currentBuffer).readInt8(currentPosition)
);
currentPosition++;
checkOverflow();
} else {
result.push(read(1).readInt8(0));
}
};
default:
if (header <= 10) {
return () => result.push(header);
} else if ((header & SHORT_STRING_HEADER) === SHORT_STRING_HEADER) {
const len = header & SHORT_STRING_LENGTH_MASK;
return () => {
if (isInCurrentBuffer(len)) {
result.push(
currentBuffer.toString(
"latin1",
currentPosition,
currentPosition + len
)
);
currentPosition += len;
checkOverflow();
} else {
result.push(read(len).toString("latin1"));
}
};
} else if ((header & NUMBERS_HEADER_MASK) === F64_HEADER) {
const len = (header & NUMBERS_COUNT_MASK) + 1;
return () => {
const need = F64_SIZE * len;
if (isInCurrentBuffer(need)) {
for (let i = 0; i < len; i++) {
result.push(
/** @type {Buffer} */ (currentBuffer).readDoubleLE(
currentPosition
)
);
currentPosition += F64_SIZE;
}
checkOverflow();
} else {
const buf = read(need);
for (let i = 0; i < len; i++) {
result.push(buf.readDoubleLE(i * F64_SIZE));
}
}
};
} else if ((header & NUMBERS_HEADER_MASK) === I32_HEADER) {
const len = (header & NUMBERS_COUNT_MASK) + 1;
return () => {
const need = I32_SIZE * len;
if (isInCurrentBuffer(need)) {
for (let i = 0; i < len; i++) {
result.push(
/** @type {Buffer} */ (currentBuffer).readInt32LE(
currentPosition
)
);
currentPosition += I32_SIZE;
}
checkOverflow();
} else {
const buf = read(need);
for (let i = 0; i < len; i++) {
result.push(buf.readInt32LE(i * I32_SIZE));
}
}
};
} else if ((header & NUMBERS_HEADER_MASK) === I8_HEADER) {
const len = (header & NUMBERS_COUNT_MASK) + 1;
return () => {
const need = I8_SIZE * len;
if (isInCurrentBuffer(need)) {
for (let i = 0; i < len; i++) {
result.push(
/** @type {Buffer} */ (currentBuffer).readInt8(
currentPosition
)
);
currentPosition += I8_SIZE;
}
checkOverflow();
} else {
const buf = read(need);
for (let i = 0; i < len; i++) {
result.push(buf.readInt8(i * I8_SIZE));
}
}
};
} else {
return () => {
throw new Error(
`Unexpected header byte 0x${header.toString(16)}`
);
};
}
}
});
/** @type {DeserializedType} */
const result = [];
while (currentBuffer !== null) {
if (typeof currentBuffer === "function") {
result.push(
SerializerMiddleware.deserializeLazy(currentBuffer, data =>
this._deserialize(data, context)
)
);
currentDataItem++;
currentBuffer =
currentDataItem < data.length ? data[currentDataItem] : null;
currentIsBuffer = Buffer.isBuffer(currentBuffer);
} else {
const header = readU8();
dispatchTable[header]();
}
}
return result;
}
}
module.exports = BinaryMiddleware;
module.exports.MEASURE_START_OPERATION = MEASURE_START_OPERATION;
module.exports.MEASURE_END_OPERATION = MEASURE_END_OPERATION;

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