Commit js, ts, and definitions in separate folders

ts_src/script_signature.ts

@@ -0,0 +1,64 @@
+import * as types from './types'
+const bip66 = require('bip66')
+
+const typeforce = require('typeforce')
+
+const ZERO = Buffer.alloc(1, 0)
+function toDER (x: Buffer): Buffer {
+  let i = 0
+  while (x[i] === 0) ++i
+  if (i === x.length) return ZERO
+  x = x.slice(i)
+  if (x[0] & 0x80) return Buffer.concat([ZERO, x], 1 + x.length)
+  return x
+}
+
+function fromDER (x: Buffer): Buffer {
+  if (x[0] === 0x00) x = x.slice(1)
+  const buffer = Buffer.alloc(32, 0)
+  const bstart = Math.max(0, 32 - x.length)
+  x.copy(buffer, bstart)
+  return buffer
+}
+
+interface ScriptSignature {
+  signature: Buffer
+  hashType: number
+}
+
+// BIP62: 1 byte hashType flag (only 0x01, 0x02, 0x03, 0x81, 0x82 and 0x83 are allowed)
+export function decode (buffer: Buffer): ScriptSignature {
+  const hashType = buffer.readUInt8(buffer.length - 1)
+  const hashTypeMod = hashType & ~0x80
+  if (hashTypeMod <= 0 || hashTypeMod >= 4) throw new Error('Invalid hashType ' + hashType)
+
+  const decode = bip66.decode(buffer.slice(0, -1))
+  const r = fromDER(decode.r)
+  const s = fromDER(decode.s)
+
+  return {
+    signature: Buffer.concat([r, s], 64),
+    hashType: hashType
+  }
+}
+
+export function encode (signature: Buffer, hashType: number): Buffer {
+  typeforce({
+    signature: types.BufferN(64),
+    hashType: types.UInt8
+  }, { signature, hashType })
+
+  const hashTypeMod = hashType & ~0x80
+  if (hashTypeMod <= 0 || hashTypeMod >= 4) throw new Error('Invalid hashType ' + hashType)
+
+  const hashTypeBuffer = Buffer.allocUnsafe(1)
+  hashTypeBuffer.writeUInt8(hashType, 0)
+
+  const r = toDER(signature.slice(0, 32))
+  const s = toDER(signature.slice(32, 64))
+
+  return Buffer.concat([
+    bip66.encode(r, s),
+    hashTypeBuffer
+  ])
+}