import struct
from parse import records

rs = records()
oc = [r for r in rs if r['name'].startswith('OC')]
assert len(oc)==8
L = set(len(r['blk']) for r in oc)
print('lengths', L)

b = [r['blk'] for r in oc]
f = [r['field'] for r in oc]

# show differing byte positions
n = len(b[0])
diff = [i for i in range(n) if len(set(x[i] for x in b))>1]
print('differing byte offsets:', [hex(i) for i in diff])
for i in diff:
    print(hex(i), [hex(x[i]) for x in b])

# GF(2) affine test: for equal-length messages, if h is affine over GF(2),
# then h(A)^h(B)^h(C)^h(D) == 0 whenever A^B^C^D == 0.
# Find quadruples among the 8 whose message-XOR is 0.
import itertools
def bx(x,y):
    return bytes(p^q for p,q in zip(x,y))
found=0
for c in itertools.combinations(range(8),4):
    m = bytes(n)
    for i in c: m = bx(m,b[i])
    if m == bytes(n):
        v = 0
        for i in c: v ^= f[i]
        print('quad', c, 'msgxor=0 fieldxor=%08x' % v)
        found+=1
print('quads with zero msg xor:', found)

# Alternative affine test using the base-block trick:
# Build a matrix over the differing bytes only.