A Object-Binary Mapper for JavaScript/TypeScript.
This is similar to C struct with a memory block.
import { defineObjectRecord } from "bre"
// Define a Record Type.
const TcpHeader = defineObjectRecord("TcpHeader", {
srcPort: "uint16",
dstPort: "uint16",
seqNo: "uint32",
ackNo: "uint32",
dataOffset: "bit4",
_reserved0: "bit6", // padding
urgCode: "bit1",
ackCode: "bit1",
pshCode: "bit1",
rstCode: "bit1",
synCode: "bit1",
finCode: "bit1",
windowSize: "uint16",
checksum: "uint16",
urgentPonter: "uint16",
})
// Connect to a Buffer (E.g., a buffer came from stream...)
const header = TcpHeader.view(a_buffer, 0)
// Read and Write the Buffer
console.log(header.srcPort, "→", header.dstPort, "🚀")
header.seqNo += 1
header.ackNo += 1
header.ackCode = 1bre's record object is just a wrapper of ArrayBuffer objects.
- The read of properties reads the connected buffer directly.
- The write of properties writes the connected buffer directly.
So the above TcpHeader example defines the class like the following automatically:
Open the defined class
class TcpHeader extends ObjectRecord {
constructor(buffer, byteOffset) {
super(buffer, byteOffset, 20)
}
static view(buffer, byteOffset = 0) {
return Object.freeze(new TcpHeader(buffer, byteOffset))
}
static get bitLength() {
return 160
}
static get byteLength() {
return 20
}
static keys(record) {
return [
"srcPort",
"dstPort",
"seqNo",
"ackNo",
"dataOffset",
"urgCode",
"ackCode",
"pshCode",
"rstCode",
"synCode",
"finCode",
"windowSize",
"checksum",
"urgentPonter",
]
}
static values(record) {
return [
record.srcPort,
record.dstPort,
record.seqNo,
record.ackNo,
record.dataOffset,
record.urgCode,
record.ackCode,
record.pshCode,
record.rstCode,
record.synCode,
record.finCode,
record.windowSize,
record.checksum,
record.urgentPonter,
]
}
static entries(record) {
return [
["srcPort", record.srcPort],
["dstPort", record.dstPort],
["seqNo", record.seqNo],
["ackNo", record.ackNo],
["dataOffset", record.dataOffset],
["urgCode", record.urgCode],
["ackCode", record.ackCode],
["pshCode", record.pshCode],
["rstCode", record.rstCode],
["synCode", record.synCode],
["finCode", record.finCode],
["windowSize", record.windowSize],
["checksum", record.checksum],
["urgentPonter", record.urgentPonter],
]
}
get srcPort() {
return this[sBuffer].getUint16(0)
}
set srcPort(value) {
assert.integer(value, "srcPort")
assert.range(value, 0, 65535, "srcPort")
this[sBuffer].setUint16(0, value)
}
get dstPort() {
return this[sBuffer].getUint16(2)
}
set dstPort(value) {
assert.integer(value, "dstPort")
assert.range(value, 0, 65535, "dstPort")
this[sBuffer].setUint16(2, value)
}
get seqNo() {
return this[sBuffer].getUint32(4)
}
set seqNo(value) {
assert.integer(value, "seqNo")
assert.range(value, 0, 4294967295, "seqNo")
this[sBuffer].setUint32(4, value)
}
get ackNo() {
return this[sBuffer].getUint32(8)
}
set ackNo(value) {
assert.integer(value, "ackNo")
assert.range(value, 0, 4294967295, "ackNo")
this[sBuffer].setUint32(8, value)
}
get dataOffset() {
const data = this[sBuffer].getUint8(12)
return (data & 240) >> 4
}
set dataOffset(value) {
assert.integer(value, "dataOffset")
assert.range(value, 0, 15, "dataOffset")
const data = this[sBuffer].getUint8(12)
this[sBuffer].setUint8(12, ((value << 4) & 240) | (data & ~240))
}
get urgCode() {
const data = this[sBuffer].getUint8(13)
return (data & 32) >> 5
}
set urgCode(value) {
assert.integer(value, "urgCode")
assert.range(value, 0, 1, "urgCode")
const data = this[sBuffer].getUint8(13)
this[sBuffer].setUint8(13, ((value << 5) & 32) | (data & ~32))
}
get ackCode() {
const data = this[sBuffer].getUint8(13)
return (data & 16) >> 4
}
set ackCode(value) {
assert.integer(value, "ackCode")
assert.range(value, 0, 1, "ackCode")
const data = this[sBuffer].getUint8(13)
this[sBuffer].setUint8(13, ((value << 4) & 16) | (data & ~16))
}
get pshCode() {
const data = this[sBuffer].getUint8(13)
return (data & 8) >> 3
}
set pshCode(value) {
assert.integer(value, "pshCode")
assert.range(value, 0, 1, "pshCode")
const data = this[sBuffer].getUint8(13)
this[sBuffer].setUint8(13, ((value << 3) & 8) | (data & ~8))
}
get rstCode() {
const data = this[sBuffer].getUint8(13)
return (data & 4) >> 2
}
set rstCode(value) {
assert.integer(value, "rstCode")
assert.range(value, 0, 1, "rstCode")
const data = this[sBuffer].getUint8(13)
this[sBuffer].setUint8(13, ((value << 2) & 4) | (data & ~4))
}
get synCode() {
const data = this[sBuffer].getUint8(13)
return (data & 2) >> 1
}
set synCode(value) {
assert.integer(value, "synCode")
assert.range(value, 0, 1, "synCode")
const data = this[sBuffer].getUint8(13)
this[sBuffer].setUint8(13, ((value << 1) & 2) | (data & ~2))
}
get finCode() {
const data = this[sBuffer].getUint8(13)
return (data & 1) >> 0
}
set finCode(value) {
assert.integer(value, "finCode")
assert.range(value, 0, 1, "finCode")
const data = this[sBuffer].getUint8(13)
this[sBuffer].setUint8(13, ((value << 0) & 1) | (data & ~1))
}
get windowSize() {
return this[sBuffer].getUint16(14)
}
set windowSize(value) {
assert.integer(value, "windowSize")
assert.range(value, 0, 65535, "windowSize")
this[sBuffer].setUint16(14, value)
}
get checksum() {
return this[sBuffer].getUint16(16)
}
set checksum(value) {
assert.integer(value, "checksum")
assert.range(value, 0, 65535, "checksum")
this[sBuffer].setUint16(16, value)
}
get urgentPonter() {
return this[sBuffer].getUint16(18)
}
set urgentPonter(value) {
assert.integer(value, "urgentPonter")
assert.range(value, 0, 65535, "urgentPonter")
this[sBuffer].setUint16(18, value)
}
}Plus, this package provides the perfect type definition for the classes that defineObjectRecord/defineArrayRecord defined.
$ npm install --save bre- Requires Node.js
>=6.0.0
TBD.
Thank you for contributing!
Use Issues/PRs on GitHub.
npm test... Runs all tests.npm run build... Compiles JavaScript code from TypeScript source code.npm run clean... Removes compiled files, temporary files, and coverage data.npm run coverage... Opens the code coverage of the lastnpm test.npm run lint... Applies ESLint to the source code.npm run watch... Runs all tests on every file changes.