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-rw-r--r--qa/rpc-tests/bignum.py102
1 files changed, 102 insertions, 0 deletions
diff --git a/qa/rpc-tests/bignum.py b/qa/rpc-tests/bignum.py
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+++ b/qa/rpc-tests/bignum.py
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+#
+#
+# bignum.py
+#
+# This file is copied from python-bitcoinlib.
+#
+# Distributed under the MIT/X11 software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+#
+
+"""Bignum routines"""
+
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import struct
+
+
+# generic big endian MPI format
+
+def bn_bytes(v, have_ext=False):
+ ext = 0
+ if have_ext:
+ ext = 1
+ return ((v.bit_length()+7)//8) + ext
+
+def bn2bin(v):
+ s = bytearray()
+ i = bn_bytes(v)
+ while i > 0:
+ s.append((v >> ((i-1) * 8)) & 0xff)
+ i -= 1
+ return s
+
+def bin2bn(s):
+ l = 0
+ for ch in s:
+ l = (l << 8) | ch
+ return l
+
+def bn2mpi(v):
+ have_ext = False
+ if v.bit_length() > 0:
+ have_ext = (v.bit_length() & 0x07) == 0
+
+ neg = False
+ if v < 0:
+ neg = True
+ v = -v
+
+ s = struct.pack(b">I", bn_bytes(v, have_ext))
+ ext = bytearray()
+ if have_ext:
+ ext.append(0)
+ v_bin = bn2bin(v)
+ if neg:
+ if have_ext:
+ ext[0] |= 0x80
+ else:
+ v_bin[0] |= 0x80
+ return s + ext + v_bin
+
+def mpi2bn(s):
+ if len(s) < 4:
+ return None
+ s_size = bytes(s[:4])
+ v_len = struct.unpack(b">I", s_size)[0]
+ if len(s) != (v_len + 4):
+ return None
+ if v_len == 0:
+ return 0
+
+ v_str = bytearray(s[4:])
+ neg = False
+ i = v_str[0]
+ if i & 0x80:
+ neg = True
+ i &= ~0x80
+ v_str[0] = i
+
+ v = bin2bn(v_str)
+
+ if neg:
+ return -v
+ return v
+
+# bitcoin-specific little endian format, with implicit size
+def mpi2vch(s):
+ r = s[4:] # strip size
+ r = r[::-1] # reverse string, converting BE->LE
+ return r
+
+def bn2vch(v):
+ return bytes(mpi2vch(bn2mpi(v)))
+
+def vch2mpi(s):
+ r = struct.pack(b">I", len(s)) # size
+ r += s[::-1] # reverse string, converting LE->BE
+ return r
+
+def vch2bn(s):
+ return mpi2bn(vch2mpi(s))
+