trezor.crypto: add hashlib.HashIO

src/trezor/crypto/hashlib.py

@@ -3,3 +3,15 @@ from TrezorCrypto import Sha256 as sha256
 from TrezorCrypto import Sha512 as sha512
 from TrezorCrypto import Sha3_256 as sha3_256
 from TrezorCrypto import Sha3_512 as sha3_512
+
+class HashIO:
+
+    def __init__(self, hashfunc=sha256):
+        self.hashfunc = hashfunc
+        self.ctx = hashfunc()
+
+    def write(self, data):
+        self.ctx.update(data)
+
+    def getvalue(self):
+        return self.ctx.digest()