protobuf-codec/decode/types.js

Minimal Protocol Buffers wire encoding/decoding

function tag (bigint) {
  const int = Number(bigint) // Safe as protoc only allows fieldNumber up to int32 + 3 bits for wireType
  const wireType = int & 0b111
  const fieldNumber = int >> 3

  return { wireType, fieldNumber }
}

function uint64 (bigint) {
  return BigInt.asUintN(64, bigint)
}

function uint32 (bigint) {
  return Number(BigInt.asUintN(32, bigint))
}

function int64 (bigint) {
  return BigInt.asIntN(64, bigint)
}

function int32 (bigint) {
  return Number(BigInt.asIntN(32, bigint))
}

function sint64 (bigint) {
  return ((bigint >> 1n) ^ (-1n * (bigint & 1n)))
}

function sint32 (bigint) {
  return Number((bigint >> 1n) ^ (-1n * (bigint & 1n)))
}

function bool (bigint) {
  return bigint !== 0n
}

function enumerable (uint) {
  return Number(uint) | 0 // trick to cast uint to int
}

function bytes (bytes) {
  return bytes
}

const _dec = new TextDecoder()
function string (bytes) {
  return _dec.decode(bytes)
}

function fixed64 (bytes) {
  return _view(bytes).getBigUint64(0, true)
}

function sfixed64 (bytes) {
  return _view(bytes).getBigInt64(0, true)
}

function double (bytes) {
  return _view(bytes).getFloat64(0, true)
}

function fixed32 (bytes) {
  return _view(bytes).getUint32(0, true)
}

function sfixed32 (bytes) {
  return _view(bytes).geInt32(0, true)
}

function float (bytes) {
  return _view(bytes).getFloat32(0, true)
}

function _view (bytes) {
  return new DataView(bytes.buffer, bytes.byteOffset, bytes.byteLength)
}

module.exports = {
  tag,
  uint64,
  uint32,
  int64,
  int32,
  sint64,
  sint32,
  bool,
  enumerable,
  bytes,
  string,
  fixed64,
  sfixed64,
  double,
  fixed32,
  sfixed32,
  float
}