Structure related functions in separate source files

package.json

@@ -88,7 +88,6 @@
     "ethjs-util": "0.1.6",
     "keccak": "^1.0.2",
     "rlp": "^2.0.0",
-    "safe-buffer": "^5.1.1",
     "secp256k1": "^3.0.1"
   },
   "devDependencies": {

src/account.ts

@@ -0,0 +1,180 @@
+const assert = require('assert')
+const ethjsUtil = require('ethjs-util')
+const secp256k1 = require('secp256k1')
+import BN = require('bn.js')
+import { toBuffer, addHexPrefix, zeros, bufferToHex, unpad } from './bytes'
+import { keccak, keccak256, rlphash } from './hash'
+
+/**
+ * Returns a zero address.
+ */
+export const zeroAddress = function(): string {
+  const addressLength = 20
+  const addr = zeros(addressLength)
+  return bufferToHex(addr)
+}
+
+/**
+ * Checks if the address is a valid. Accepts checksummed addresses too.
+ */
+export const isValidAddress = function(address: string): boolean {
+  return /^0x[0-9a-fA-F]{40}$/.test(address)
+}
+
+/**
+ * Checks if a given address is a zero address.
+ */
+export const isZeroAddress = function(address: string): boolean {
+  const zeroAddr = zeroAddress()
+  return zeroAddr === addHexPrefix(address)
+}
+
+/**
+ * Returns a checksummed address.
+ */
+export const toChecksumAddress = function(address: string): string {
+  address = ethjsUtil.stripHexPrefix(address).toLowerCase()
+  const hash = keccak(address).toString('hex')
+  let ret = '0x'
+
+  for (let i = 0; i < address.length; i++) {
+    if (parseInt(hash[i], 16) >= 8) {
+      ret += address[i].toUpperCase()
+    } else {
+      ret += address[i]
+    }
+  }
+
+  return ret
+}
+
+/**
+ * Checks if the address is a valid checksummed address.
+ */
+export const isValidChecksumAddress = function(address: string): boolean {
+  return isValidAddress(address) && toChecksumAddress(address) === address
+}
+
+/**
+ * Generates an address of a newly created contract.
+ * @param from The address which is creating this new address
+ * @param nonce The nonce of the from account
+ */
+export const generateAddress = function(from: Buffer, nonce: Buffer): Buffer {
+  from = toBuffer(from)
+  const nonceBN = new BN(nonce)
+
+  if (nonceBN.isZero()) {
+    // in RLP we want to encode null in the case of zero nonce
+    // read the RLP documentation for an answer if you dare
+    return rlphash([from, null]).slice(-20)
+  }
+
+  // Only take the lower 160bits of the hash
+  return rlphash([from, Buffer.from(nonceBN.toArray())]).slice(-20)
+}
+
+/**
+ * Generates an address for a contract created using CREATE2.
+ * @param from The address which is creating this new address
+ * @param salt A salt
+ * @param initCode The init code of the contract being created
+ */
+export const generateAddress2 = function(
+  from: Buffer | string,
+  salt: Buffer | string,
+  initCode: Buffer | string,
+): Buffer {
+  const fromBuf = toBuffer(from)
+  const saltBuf = toBuffer(salt)
+  const initCodeBuf = toBuffer(initCode)
+
+  assert(fromBuf.length === 20)
+  assert(saltBuf.length === 32)
+
+  const address = keccak256(
+    Buffer.concat([Buffer.from('ff', 'hex'), fromBuf, saltBuf, keccak256(initCodeBuf)]),
+  )
+
+  return address.slice(-20)
+}
+
+/**
+ * Returns true if the supplied address belongs to a precompiled account (Byzantium).
+ */
+export const isPrecompiled = function(address: Buffer | string): boolean {
+  const a = unpad(address)
+  return a.length === 1 && a[0] >= 1 && a[0] <= 8
+}
+
+/**
+ * Checks if the private key satisfies the rules of the curve secp256k1.
+ */
+export const isValidPrivate = function(privateKey: Buffer): boolean {
+  return secp256k1.privateKeyVerify(privateKey)
+}
+
+/**
+ * Checks if the public key satisfies the rules of the curve secp256k1
+ * and the requirements of Ethereum.
+ * @param publicKey The two points of an uncompressed key, unless sanitize is enabled
+ * @param sanitize Accept public keys in other formats
+ */
+export const isValidPublic = function(publicKey: Buffer, sanitize: boolean = false): boolean {
+  if (publicKey.length === 64) {
+    // Convert to SEC1 for secp256k1
+    return secp256k1.publicKeyVerify(Buffer.concat([Buffer.from([4]), publicKey]))
+  }
+
+  if (!sanitize) {
+    return false
+  }
+
+  return secp256k1.publicKeyVerify(publicKey)
+}
+
+/**
+ * Returns the ethereum address of a given public key.
+ * Accepts "Ethereum public keys" and SEC1 encoded keys.
+ * @param pubKey The two points of an uncompressed key, unless sanitize is enabled
+ * @param sanitize Accept public keys in other formats
+ */
+export const pubToAddress = function(pubKey: Buffer, sanitize: boolean = false): Buffer {
+  pubKey = toBuffer(pubKey)
+  if (sanitize && pubKey.length !== 64) {
+    pubKey = secp256k1.publicKeyConvert(pubKey, false).slice(1)
+  }
+  assert(pubKey.length === 64)
+  // Only take the lower 160bits of the hash
+  return keccak(pubKey).slice(-20)
+}
+export const publicToAddress = pubToAddress
+
+/**
+ * Returns the ethereum address of a given private key.
+ * @param privateKey A private key must be 256 bits wide
+ */
+export const privateToAddress = function(privateKey: Buffer): Buffer {
+  return publicToAddress(privateToPublic(privateKey))
+}
+
+/**
+ * Returns the ethereum public key of a given private key.
+ * @param privateKey A private key must be 256 bits wide
+ */
+export const privateToPublic = function(privateKey: Buffer): Buffer {
+  privateKey = toBuffer(privateKey)
+  // skip the type flag and use the X, Y points
+  return secp256k1.publicKeyCreate(privateKey, false).slice(1)
+}
+
+/**
+ * Converts a public key to the Ethereum format.
+ */
+export const importPublic = function(publicKey: Buffer): Buffer {
+  publicKey = toBuffer(publicKey)
+  if (publicKey.length !== 64) {
+    publicKey = secp256k1.publicKeyConvert(publicKey, false).slice(1)
+  }
+  return publicKey
+}

src/bytes.ts

@@ -0,0 +1,156 @@
+const ethjsUtil = require('ethjs-util')
+import BN = require('bn.js')
+
+/**
+ * Returns a buffer filled with 0s.
+ * @param bytes the number of bytes the buffer should be
+ */
+export const zeros = function(bytes: number): Buffer {
+  return Buffer.allocUnsafe(bytes).fill(0)
+}
+
+/**
+ * Left Pads an `Array` or `Buffer` with leading zeros till it has `length` bytes.
+ * Or it truncates the beginning if it exceeds.
+ * @param msg the value to pad (Buffer|Array)
+ * @param length the number of bytes the output should be
+ * @param right whether to start padding form the left or right
+ * @return (Buffer|Array)
+ */
+export const setLengthLeft = function(msg: any, length: number, right: boolean = false) {
+  const buf = zeros(length)
+  msg = toBuffer(msg)
+  if (right) {
+    if (msg.length < length) {
+      msg.copy(buf)
+      return buf
+    }
+    return msg.slice(0, length)
+  } else {
+    if (msg.length < length) {
+      msg.copy(buf, length - msg.length)
+      return buf
+    }
+    return msg.slice(-length)
+  }
+}
+export const setLength = setLengthLeft
+
+/**
+ * Right Pads an `Array` or `Buffer` with leading zeros till it has `length` bytes.
+ * Or it truncates the beginning if it exceeds.
+ * @param msg the value to pad (Buffer|Array)
+ * @param length the number of bytes the output should be
+ * @return (Buffer|Array)
+ */
+export const setLengthRight = function(msg: any, length: number) {
+  return setLength(msg, length, true)
+}
+
+/**
+ * Trims leading zeros from a `Buffer` or an `Array`.
+ * @param a (Buffer|Array|String)
+ * @return (Buffer|Array|String)
+ */
+export const unpad = function(a: any) {
+  a = ethjsUtil.stripHexPrefix(a)
+  let first = a[0]
+  while (a.length > 0 && first.toString() === '0') {
+    a = a.slice(1)
+    first = a[0]
+  }
+  return a
+}
+export const stripZeros = unpad
+
+/**
+ * Attempts to turn a value into a `Buffer`. As input it supports `Buffer`, `String`, `Number`, null/undefined, `BN` and other objects with a `toArray()` method.
+ * @param v the value
+ */
+export const toBuffer = function(v: any): Buffer {
+  if (!Buffer.isBuffer(v)) {
+    if (Array.isArray(v)) {
+      v = Buffer.from(v)
+    } else if (typeof v === 'string') {
+      if (ethjsUtil.isHexString(v)) {
+        v = Buffer.from(ethjsUtil.padToEven(ethjsUtil.stripHexPrefix(v)), 'hex')
+      } else {
+        v = Buffer.from(v)
+      }
+    } else if (typeof v === 'number') {
+      v = ethjsUtil.intToBuffer(v)
+    } else if (v === null || v === undefined) {
+      v = Buffer.allocUnsafe(0)
+    } else if (BN.isBN(v)) {
+      v = v.toArrayLike(Buffer)
+    } else if (v.toArray) {
+      // converts a BN to a Buffer
+      v = Buffer.from(v.toArray())
+    } else {
+      throw new Error('invalid type')
+    }
+  }
+  return v
+}
+
+/**
+ * Converts a `Buffer` to a `Number`.
+ * @param buf `Buffer` object to convert
+ * @throws If the input number exceeds 53 bits.
+ */
+export const bufferToInt = function(buf: Buffer): number {
+  return new BN(toBuffer(buf)).toNumber()
+}
+
+/**
+ * Converts a `Buffer` into a hex `String`.
+ * @param buf `Buffer` object to convert
+ */
+export const bufferToHex = function(buf: Buffer): string {
+  buf = toBuffer(buf)
+  return '0x' + buf.toString('hex')
+}
+
+/**
+ * Interprets a `Buffer` as a signed integer and returns a `BN`. Assumes 256-bit numbers.
+ * @param num Signed integer value
+ */
+export const fromSigned = function(num: Buffer): BN {
+  return new BN(num).fromTwos(256)
+}
+
+/**
+ * Converts a `BN` to an unsigned integer and returns it as a `Buffer`. Assumes 256-bit numbers.
+ * @param num
+ */
+export const toUnsigned = function(num: BN): Buffer {
+  return Buffer.from(num.toTwos(256).toArray())
+}
+
+/**
+ * Adds "0x" to a given `String` if it does not already start with "0x".
+ */
+export const addHexPrefix = function(str: string): string {
+  if (typeof str !== 'string') {
+    return str
+  }
+
+  return ethjsUtil.isHexPrefixed(str) ? str : '0x' + str
+}
+
+/**
+ * Converts a `Buffer` or `Array` to JSON.
+ * @param ba (Buffer|Array)
+ * @return (Array|String|null)
+ */
+export const baToJSON = function(ba: any): any {
+  if (Buffer.isBuffer(ba)) {
+    return `0x${ba.toString('hex')}`
+  } else if (ba instanceof Array) {
+    const array = []
+    for (let i = 0; i < ba.length; i++) {
+      array.push(baToJSON(ba[i]))
+    }
+    return array
+  }
+}