electrum/lib/deserialize.py

# this code comes from ABE. it can probably be simplified
#
#

from bitcoin import public_key_to_bc_address, hash_160_to_bc_address, hash_encode, hash_160
from util import print_error
#import socket
import time
import struct

#
# Workalike python implementation of Bitcoin's CDataStream class.
#
import struct
import StringIO
import mmap

class SerializationError(Exception):
    """ Thrown when there's a problem deserializing or serializing """

class BCDataStream(object):
    def __init__(self):
        self.input = None
        self.read_cursor = 0

    def clear(self):
        self.input = None
        self.read_cursor = 0

    def write(self, bytes):  # Initialize with string of bytes
        if self.input is None:
            self.input = bytes
        else:
            self.input += bytes

    def map_file(self, file, start):  # Initialize with bytes from file
        self.input = mmap.mmap(file.fileno(), 0, access=mmap.ACCESS_READ)
        self.read_cursor = start

    def seek_file(self, position):
        self.read_cursor = position
        
    def close_file(self):
        self.input.close()

    def read_string(self):
        # Strings are encoded depending on length:
        # 0 to 252 :  1-byte-length followed by bytes (if any)
        # 253 to 65,535 : byte'253' 2-byte-length followed by bytes
        # 65,536 to 4,294,967,295 : byte '254' 4-byte-length followed by bytes
        # ... and the Bitcoin client is coded to understand:
        # greater than 4,294,967,295 : byte '255' 8-byte-length followed by bytes of string
        # ... but I don't think it actually handles any strings that big.
        if self.input is None:
            raise SerializationError("call write(bytes) before trying to deserialize")

        try:
            length = self.read_compact_size()
        except IndexError:
            raise SerializationError("attempt to read past end of buffer")

        return self.read_bytes(length)

    def write_string(self, string):
        # Length-encoded as with read-string
        self.write_compact_size(len(string))
        self.write(string)

    def read_bytes(self, length):
        try:
            result = self.input[self.read_cursor:self.read_cursor+length]
            self.read_cursor += length
            return result
        except IndexError:
            raise SerializationError("attempt to read past end of buffer")

        return ''

    def read_boolean(self): return self.read_bytes(1)[0] != chr(0)
    def read_int16(self): return self._read_num('<h')
    def read_uint16(self): return self._read_num('<H')
    def read_int32(self): return self._read_num('<i')
    def read_uint32(self): return self._read_num('<I')
    def read_int64(self): return self._read_num('<q')
    def read_uint64(self): return self._read_num('<Q')

    def write_boolean(self, val): return self.write(chr(1) if val else chr(0))
    def write_int16(self, val): return self._write_num('<h', val)
    def write_uint16(self, val): return self._write_num('<H', val)
    def write_int32(self, val): return self._write_num('<i', val)
    def write_uint32(self, val): return self._write_num('<I', val)
    def write_int64(self, val): return self._write_num('<q', val)
    def write_uint64(self, val): return self._write_num('<Q', val)

    def read_compact_size(self):
        size = ord(self.input[self.read_cursor])
        self.read_cursor += 1
        if size == 253:
            size = self._read_num('<H')
        elif size == 254:
            size = self._read_num('<I')
        elif size == 255:
            size = self._read_num('<Q')
        return size

    def write_compact_size(self, size):
        if size < 0:
            raise SerializationError("attempt to write size < 0")
        elif size < 253:
            self.write(chr(size))
        elif size < 2**16:
            self.write('\xfd')
            self._write_num('<H', size)
        elif size < 2**32:
            self.write('\xfe')
            self._write_num('<I', size)
        elif size < 2**64:
            self.write('\xff')
            self._write_num('<Q', size)

    def _read_num(self, format):
        (i,) = struct.unpack_from(format, self.input, self.read_cursor)
        self.read_cursor += struct.calcsize(format)
        return i

    def _write_num(self, format, num):
        s = struct.pack(format, num)
        self.write(s)

#
# enum-like type
# From the Python Cookbook, downloaded from http://code.activestate.com/recipes/67107/
#
import types, string, exceptions

class EnumException(exceptions.Exception):
    pass

class Enumeration:
    def __init__(self, name, enumList):
        self.__doc__ = name
        lookup = { }
        reverseLookup = { }
        i = 0
        uniqueNames = [ ]
        uniqueValues = [ ]
        for x in enumList:
            if type(x) == types.TupleType:
                x, i = x
            if type(x) != types.StringType:
                raise EnumException, "enum name is not a string: " + x
            if type(i) != types.IntType:
                raise EnumException, "enum value is not an integer: " + i
            if x in uniqueNames:
                raise EnumException, "enum name is not unique: " + x
            if i in uniqueValues:
                raise EnumException, "enum value is not unique for " + x
            uniqueNames.append(x)
            uniqueValues.append(i)
            lookup[x] = i
            reverseLookup[i] = x
            i = i + 1
        self.lookup = lookup
        self.reverseLookup = reverseLookup
    def __getattr__(self, attr):
        if not self.lookup.has_key(attr):
            raise AttributeError
        return self.lookup[attr]
    def whatis(self, value):
        return self.reverseLookup[value]


# This function comes from bitcointools, bct-LICENSE.txt.
def long_hex(bytes):
    return bytes.encode('hex_codec')

# This function comes from bitcointools, bct-LICENSE.txt.
def short_hex(bytes):
    t = bytes.encode('hex_codec')
    if len(t) < 11:
        return t
    return t[0:4]+"..."+t[-4:]



def parse_TxIn(vds):
    d = {}
    d['prevout_hash'] = hash_encode(vds.read_bytes(32))
    d['prevout_n'] = vds.read_uint32()
    scriptSig = vds.read_bytes(vds.read_compact_size())
    d['sequence'] = vds.read_uint32()

    if scriptSig:
        pubkeys, signatures, address = get_address_from_input_script(scriptSig)
    else:
        pubkeys = []
        signatures = []
        address = None
    
    d['address'] = address
    d['signatures'] = signatures

    return d


def parse_TxOut(vds, i):
    d = {}
    d['value'] = vds.read_int64()
    scriptPubKey = vds.read_bytes(vds.read_compact_size())
    d['address'] = get_address_from_output_script(scriptPubKey)
    d['raw_output_script'] = scriptPubKey.encode('hex')
    d['index'] = i
    return d


def parse_Transaction(vds):
    d = {}
    start = vds.read_cursor
    d['version'] = vds.read_int32()
    n_vin = vds.read_compact_size()
    d['inputs'] = []
    for i in xrange(n_vin):
        d['inputs'].append(parse_TxIn(vds))
    n_vout = vds.read_compact_size()
    d['outputs'] = []
    for i in xrange(n_vout):
        d['outputs'].append(parse_TxOut(vds, i))
    d['lockTime'] = vds.read_uint32()
    return d

def parse_redeemScript(bytes):
    dec = [ x for x in script_GetOp(bytes.decode('hex')) ]

    # 2 of 2
    match = [ opcodes.OP_2, opcodes.OP_PUSHDATA4, opcodes.OP_PUSHDATA4, opcodes.OP_2, opcodes.OP_CHECKMULTISIG ]
    if match_decoded(dec, match):
        pubkeys = [ dec[1][1].encode('hex'), dec[2][1].encode('hex') ]
        return 2, pubkeys

    # 2 of 3
    match = [ opcodes.OP_2, opcodes.OP_PUSHDATA4, opcodes.OP_PUSHDATA4, opcodes.OP_PUSHDATA4, opcodes.OP_3, opcodes.OP_CHECKMULTISIG ]
    if match_decoded(dec, match):
        pubkeys = [ dec[1][1].encode('hex'), dec[2][1].encode('hex'), dec[3][1].encode('hex') ]
        return 2, pubkeys



opcodes = Enumeration("Opcodes", [
    ("OP_0", 0), ("OP_PUSHDATA1",76), "OP_PUSHDATA2", "OP_PUSHDATA4", "OP_1NEGATE", "OP_RESERVED",
    "OP_1", "OP_2", "OP_3", "OP_4", "OP_5", "OP_6", "OP_7",
    "OP_8", "OP_9", "OP_10", "OP_11", "OP_12", "OP_13", "OP_14", "OP_15", "OP_16",
    "OP_NOP", "OP_VER", "OP_IF", "OP_NOTIF", "OP_VERIF", "OP_VERNOTIF", "OP_ELSE", "OP_ENDIF", "OP_VERIFY",
    "OP_RETURN", "OP_TOALTSTACK", "OP_FROMALTSTACK", "OP_2DROP", "OP_2DUP", "OP_3DUP", "OP_2OVER", "OP_2ROT", "OP_2SWAP",
    "OP_IFDUP", "OP_DEPTH", "OP_DROP", "OP_DUP", "OP_NIP", "OP_OVER", "OP_PICK", "OP_ROLL", "OP_ROT",
    "OP_SWAP", "OP_TUCK", "OP_CAT", "OP_SUBSTR", "OP_LEFT", "OP_RIGHT", "OP_SIZE", "OP_INVERT", "OP_AND",
    "OP_OR", "OP_XOR", "OP_EQUAL", "OP_EQUALVERIFY", "OP_RESERVED1", "OP_RESERVED2", "OP_1ADD", "OP_1SUB", "OP_2MUL",
    "OP_2DIV", "OP_NEGATE", "OP_ABS", "OP_NOT", "OP_0NOTEQUAL", "OP_ADD", "OP_SUB", "OP_MUL", "OP_DIV",
    "OP_MOD", "OP_LSHIFT", "OP_RSHIFT", "OP_BOOLAND", "OP_BOOLOR",
    "OP_NUMEQUAL", "OP_NUMEQUALVERIFY", "OP_NUMNOTEQUAL", "OP_LESSTHAN",
    "OP_GREATERTHAN", "OP_LESSTHANOREQUAL", "OP_GREATERTHANOREQUAL", "OP_MIN", "OP_MAX",
    "OP_WITHIN", "OP_RIPEMD160", "OP_SHA1", "OP_SHA256", "OP_HASH160",
    "OP_HASH256", "OP_CODESEPARATOR", "OP_CHECKSIG", "OP_CHECKSIGVERIFY", "OP_CHECKMULTISIG",
    "OP_CHECKMULTISIGVERIFY",
    ("OP_SINGLEBYTE_END", 0xF0),
    ("OP_DOUBLEBYTE_BEGIN", 0xF000),
    "OP_PUBKEY", "OP_PUBKEYHASH",
    ("OP_INVALIDOPCODE", 0xFFFF),
])


def script_GetOp(bytes):
    i = 0
    while i < len(bytes):
        vch = None
        opcode = ord(bytes[i])
        i += 1
        if opcode >= opcodes.OP_SINGLEBYTE_END:
            opcode <<= 8
            opcode |= ord(bytes[i])
            i += 1

        if opcode <= opcodes.OP_PUSHDATA4:
            nSize = opcode
            if opcode == opcodes.OP_PUSHDATA1:
                nSize = ord(bytes[i])
                i += 1
            elif opcode == opcodes.OP_PUSHDATA2:
                (nSize,) = struct.unpack_from('<H', bytes, i)
                i += 2
            elif opcode == opcodes.OP_PUSHDATA4:
                (nSize,) = struct.unpack_from('<I', bytes, i)
                i += 4
            vch = bytes[i:i+nSize]
            i += nSize

        yield (opcode, vch, i)


def script_GetOpName(opcode):
    return (opcodes.whatis(opcode)).replace("OP_", "")


def decode_script(bytes):
    result = ''
    for (opcode, vch, i) in script_GetOp(bytes):
        if len(result) > 0: result += " "
        if opcode <= opcodes.OP_PUSHDATA4:
            result += "%d:"%(opcode,)
            result += short_hex(vch)
        else:
            result += script_GetOpName(opcode)
    return result


def match_decoded(decoded, to_match):
    if len(decoded) != len(to_match):
        return False;
    for i in range(len(decoded)):
        if to_match[i] == opcodes.OP_PUSHDATA4 and decoded[i][0] <= opcodes.OP_PUSHDATA4 and decoded[i][0]>0:
            continue  # Opcodes below OP_PUSHDATA4 all just push data onto stack, and are equivalent.
        if to_match[i] != decoded[i][0]:
            return False
    return True

def get_address_from_input_script(bytes):
    try:
        decoded = [ x for x in script_GetOp(bytes) ]
    except:
        # coinbase transactions raise an exception
        print_error("cannot find address in input script", bytes.encode('hex'))
        return [], [], "(None)"

    # non-generated TxIn transactions push a signature
    # (seventy-something bytes) and then their public key
    # (65 bytes) onto the stack:
    match = [ opcodes.OP_PUSHDATA4, opcodes.OP_PUSHDATA4 ]
    if match_decoded(decoded, match):
        return None, None, public_key_to_bc_address(decoded[1][1])

    # p2sh transaction, 2 of n
    match = [ opcodes.OP_0 ]
    while len(match) < len(decoded):
        match.append(opcodes.OP_PUSHDATA4)

    if match_decoded(decoded, match):

        redeemScript = decoded[-1][1]
        num = len(match) - 2
        signatures = map(lambda x:x[1].encode('hex'), decoded[1:-1])
        
        dec2 = [ x for x in script_GetOp(redeemScript) ]

        # 2 of 2
        match2 = [ opcodes.OP_2, opcodes.OP_PUSHDATA4, opcodes.OP_PUSHDATA4, opcodes.OP_2, opcodes.OP_CHECKMULTISIG ]
        if match_decoded(dec2, match2):
            pubkeys = [ dec2[1][1].encode('hex'), dec2[2][1].encode('hex') ]
            return pubkeys, signatures, hash_160_to_bc_address(hash_160(redeemScript), 5)
 
        # 2 of 3
        match2 = [ opcodes.OP_2, opcodes.OP_PUSHDATA4, opcodes.OP_PUSHDATA4, opcodes.OP_PUSHDATA4, opcodes.OP_3, opcodes.OP_CHECKMULTISIG ]
        if match_decoded(dec2, match2):
            pubkeys = [ dec2[1][1].encode('hex'), dec2[2][1].encode('hex'), dec2[3][1].encode('hex') ]
            return pubkeys, signatures, hash_160_to_bc_address(hash_160(redeemScript), 5)

    print_error("cannot find address in input script", bytes.encode('hex'))
    return [], [], "(None)"



def get_address_from_output_script(bytes):
    decoded = [ x for x in script_GetOp(bytes) ]

    # The Genesis Block, self-payments, and pay-by-IP-address payments look like:
    # 65 BYTES:... CHECKSIG
    match = [ opcodes.OP_PUSHDATA4, opcodes.OP_CHECKSIG ]
    if match_decoded(decoded, match):
        return public_key_to_bc_address(decoded[0][1])

    # Pay-by-Bitcoin-address TxOuts look like:
    # DUP HASH160 20 BYTES:... EQUALVERIFY CHECKSIG
    match = [ opcodes.OP_DUP, opcodes.OP_HASH160, opcodes.OP_PUSHDATA4, opcodes.OP_EQUALVERIFY, opcodes.OP_CHECKSIG ]
    if match_decoded(decoded, match):
        return hash_160_to_bc_address(decoded[2][1])

    # p2sh
    match = [ opcodes.OP_HASH160, opcodes.OP_PUSHDATA4, opcodes.OP_EQUAL ]
    if match_decoded(decoded, match):
        return hash_160_to_bc_address(decoded[1][1],5)

    return "(None)"