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def murmur3_32(data, seed=0):
"""MurmurHash3 was written by Austin Appleby, and is placed in the
public domain. The author hereby disclaims copyright to this source
code."""
c1 = 0xCC9E2D51
c2 = 0x1B873593
length = len(data)
h1 = seed
roundedEnd = length & 0xFFFFFFFC # round down to 4 byte block
for i in range(0, roundedEnd, 4):
# little endian load order
k1 = (
(ord(data[i]) & 0xFF)
| ((ord(data[i + 1]) & 0xFF) << 8)
| ((ord(data[i + 2]) & 0xFF) << 16)
| (ord(data[i + 3]) << 24)
)
k1 *= c1
k1 = (k1 << 15) | ((k1 & 0xFFFFFFFF) >> 17) # ROTL32(k1,15)
k1 *= c2
h1 ^= k1
h1 = (h1 << 13) | ((h1 & 0xFFFFFFFF) >> 19) # ROTL32(h1,13)
h1 = h1 * 5 + 0xE6546B64
# tail
k1 = 0
val = length & 0x03
if val == 3:
k1 = (ord(data[roundedEnd + 2]) & 0xFF) << 16
# fallthrough
if val in [2, 3]:
k1 |= (ord(data[roundedEnd + 1]) & 0xFF) << 8
# fallthrough
if val in [1, 2, 3]:
k1 |= ord(data[roundedEnd]) & 0xFF
k1 *= c1
k1 = (k1 << 15) | ((k1 & 0xFFFFFFFF) >> 17) # ROTL32(k1,15)
k1 *= c2
h1 ^= k1
# finalization
h1 ^= length
# fmix(h1)
h1 ^= (h1 & 0xFFFFFFFF) >> 16
h1 *= 0x85EBCA6B
h1 ^= (h1 & 0xFFFFFFFF) >> 13
h1 *= 0xC2B2AE35
h1 ^= (h1 & 0xFFFFFFFF) >> 16
return h1 & 0xFFFFFFFF
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