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