# Translated from the reference implementation
|
# at https://github.com/veorq/SipHash
|
|
cimport cython
|
from libc.stdlib cimport (
|
free,
|
malloc,
|
)
|
|
import numpy as np
|
|
from numpy cimport (
|
import_array,
|
ndarray,
|
uint8_t,
|
uint64_t,
|
)
|
|
import_array()
|
|
from pandas._libs.util cimport is_nan
|
|
|
@cython.boundscheck(False)
|
def hash_object_array(
|
ndarray[object] arr, str key, str encoding="utf8"
|
) -> np.ndarray[np.uint64]:
|
"""
|
Parameters
|
----------
|
arr : 1-d object ndarray of objects
|
key : hash key, must be 16 byte len encoded
|
encoding : encoding for key & arr, default to 'utf8'
|
|
Returns
|
-------
|
1-d uint64 ndarray of hashes.
|
|
Raises
|
------
|
TypeError
|
If the array contains mixed types.
|
|
Notes
|
-----
|
Allowed values must be strings, or nulls
|
mixed array types will raise TypeError.
|
"""
|
cdef:
|
Py_ssize_t i, n
|
uint64_t[::1] result
|
bytes data, k
|
uint8_t *kb
|
uint64_t *lens
|
char **vecs
|
char *cdata
|
object val
|
list datas = []
|
|
k = <bytes>key.encode(encoding)
|
kb = <uint8_t *>k
|
if len(k) != 16:
|
raise ValueError(
|
f"key should be a 16-byte string encoded, got {k} (len {len(k)})"
|
)
|
|
n = len(arr)
|
|
# create an array of bytes
|
vecs = <char **>malloc(n * sizeof(char *))
|
lens = <uint64_t*>malloc(n * sizeof(uint64_t))
|
|
for i in range(n):
|
val = arr[i]
|
if isinstance(val, bytes):
|
data = <bytes>val
|
elif isinstance(val, str):
|
data = <bytes>val.encode(encoding)
|
elif val is None or is_nan(val):
|
# null, stringify and encode
|
data = <bytes>str(val).encode(encoding)
|
|
elif isinstance(val, tuple):
|
# GH#28969 we could have a tuple, but need to ensure that
|
# the tuple entries are themselves hashable before converting
|
# to str
|
hash(val)
|
data = <bytes>str(val).encode(encoding)
|
else:
|
raise TypeError(
|
f"{val} of type {type(val)} is not a valid type for hashing, "
|
"must be string or null"
|
)
|
|
lens[i] = len(data)
|
cdata = data
|
|
# keep the references alive through the end of the
|
# function
|
datas.append(data)
|
vecs[i] = cdata
|
|
result = np.empty(n, dtype=np.uint64)
|
with nogil:
|
for i in range(n):
|
result[i] = low_level_siphash(<uint8_t *>vecs[i], lens[i], kb)
|
|
free(vecs)
|
free(lens)
|
return result.base # .base to retrieve underlying np.ndarray
|
|
|
cdef uint64_t _rotl(uint64_t x, uint64_t b) nogil:
|
return (x << b) | (x >> (64 - b))
|
|
|
cdef uint64_t u8to64_le(uint8_t* p) nogil:
|
return (<uint64_t>p[0] |
|
<uint64_t>p[1] << 8 |
|
<uint64_t>p[2] << 16 |
|
<uint64_t>p[3] << 24 |
|
<uint64_t>p[4] << 32 |
|
<uint64_t>p[5] << 40 |
|
<uint64_t>p[6] << 48 |
|
<uint64_t>p[7] << 56)
|
|
|
cdef void _sipround(uint64_t* v0, uint64_t* v1,
|
uint64_t* v2, uint64_t* v3) nogil:
|
v0[0] += v1[0]
|
v1[0] = _rotl(v1[0], 13)
|
v1[0] ^= v0[0]
|
v0[0] = _rotl(v0[0], 32)
|
v2[0] += v3[0]
|
v3[0] = _rotl(v3[0], 16)
|
v3[0] ^= v2[0]
|
v0[0] += v3[0]
|
v3[0] = _rotl(v3[0], 21)
|
v3[0] ^= v0[0]
|
v2[0] += v1[0]
|
v1[0] = _rotl(v1[0], 17)
|
v1[0] ^= v2[0]
|
v2[0] = _rotl(v2[0], 32)
|
|
|
@cython.cdivision(True)
|
cdef uint64_t low_level_siphash(uint8_t* data, size_t datalen,
|
uint8_t* key) nogil:
|
cdef uint64_t v0 = 0x736f6d6570736575ULL
|
cdef uint64_t v1 = 0x646f72616e646f6dULL
|
cdef uint64_t v2 = 0x6c7967656e657261ULL
|
cdef uint64_t v3 = 0x7465646279746573ULL
|
cdef uint64_t b
|
cdef uint64_t k0 = u8to64_le(key)
|
cdef uint64_t k1 = u8to64_le(key + 8)
|
cdef uint64_t m
|
cdef int i
|
cdef uint8_t* end = data + datalen - (datalen % sizeof(uint64_t))
|
cdef int left = datalen & 7
|
cdef int cROUNDS = 2
|
cdef int dROUNDS = 4
|
|
b = (<uint64_t>datalen) << 56
|
v3 ^= k1
|
v2 ^= k0
|
v1 ^= k1
|
v0 ^= k0
|
|
while (data != end):
|
m = u8to64_le(data)
|
v3 ^= m
|
for i in range(cROUNDS):
|
_sipround(&v0, &v1, &v2, &v3)
|
v0 ^= m
|
|
data += sizeof(uint64_t)
|
|
for i in range(left-1, -1, -1):
|
b |= (<uint64_t>data[i]) << (i * 8)
|
|
v3 ^= b
|
|
for i in range(cROUNDS):
|
_sipround(&v0, &v1, &v2, &v3)
|
|
v0 ^= b
|
v2 ^= 0xff
|
|
for i in range(dROUNDS):
|
_sipround(&v0, &v1, &v2, &v3)
|
|
b = v0 ^ v1 ^ v2 ^ v3
|
|
return b
|
