Initial commit

[stratum-mining.git] / lib / coinbasetx.py

diff --git a/lib/coinbasetx.py b/lib/coinbasetx.py
new file mode 100644 (file)
index 0000000..11c7e36
--- /dev/null
+++ b/lib/coinbasetx.py
@@ -0,0 +1,49 @@
+import binascii
+import halfnode
+import struct
+import util
+
+class CoinbaseTransaction(halfnode.CTransaction):
+    '''Construct special transaction used for coinbase tx.
+    It also implements quick serialization using pre-cached
+    scriptSig template.'''
+    
+    extranonce_type = '>Q'
+    extranonce_placeholder = struct.pack(extranonce_type, int('f000000ff111111f', 16))
+    extranonce_size = struct.calcsize(extranonce_type)
+
+    def __init__(self, timestamper, coinbaser, value, flags, height, data):
+        super(CoinbaseTransaction, self).__init__()
+        
+        #self.extranonce = 0
+        
+        if len(self.extranonce_placeholder) != self.extranonce_size:
+            raise Exception("Extranonce placeholder don't match expected length!")
+
+        tx_in = halfnode.CTxIn()
+        tx_in.prevout.hash = 0L
+        tx_in.prevout.n = 2**32-1
+        tx_in._scriptSig_template = (
+            util.ser_number(height) + binascii.unhexlify(flags) + util.ser_number(int(timestamper.time())) + \
+            chr(self.extranonce_size),
+            util.ser_string(coinbaser.get_coinbase_data() + data)
+        )
+                
+        tx_in.scriptSig = tx_in._scriptSig_template[0] + self.extranonce_placeholder + tx_in._scriptSig_template[1]
+    
+        tx_out = halfnode.CTxOut()
+        tx_out.nValue = value
+        tx_out.scriptPubKey = coinbaser.get_script_pubkey()
+        
+        self.vin.append(tx_in)
+        self.vout.append(tx_out)
+        
+        # Two parts of serialized coinbase, just put part1 + extranonce + part2 to have final serialized tx
+        self._serialized = super(CoinbaseTransaction, self).serialize().split(self.extranonce_placeholder)
+
+    def set_extranonce(self, extranonce):
+        if len(extranonce) != self.extranonce_size:
+            raise Exception("Incorrect extranonce size")
+        
+        (part1, part2) = self.vin[0]._scriptSig_template
+        self.vin[0].scriptSig = part1 + extranonce + part2
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