def _Py_HashBytes(val, _len):
if (_len == 0):
return process_return(0)
if (_len < _Py_HASH_CUTOFF):
# TODO: this branch needs testing, needs a CPython setup for it!
# /* Optimize hashing of very small strings with inline DJBX33A. */
_hash = _Py_uhash_t(5381) # /* DJBX33A starts with 5381 */
for idx in range(_len):
_hash = ((_hash << 5) + _hash) + np.uint8(grab_byte(val, idx))
_hash ^= _len
_hash ^= _load_hashsecret('djbx33a_suffix')
else:
tmp = _siphash24(types.uint64(_load_hashsecret('siphash_k0')),
types.uint64(_load_hashsecret('siphash_k1')),
val, _len)
_hash = process_return(tmp)
return process_return(_hash)
def _siphash24(k0, k1, src, src_sz):
b = types.uint64(src_sz) << 56
v0 = k0 ^ types.uint64(0x736f6d6570736575)
v1 = k1 ^ types.uint64(0x646f72616e646f6d)
v2 = k0 ^ types.uint64(0x6c7967656e657261)
v3 = k1 ^ types.uint64(0x7465646279746573)
idx = 0
while (src_sz >= 8):
mi = grab_uint64_t(src, idx)
idx += 1
src_sz -= 8
v3 ^= mi
v0, v1, v2, v3 = _DOUBLE_ROUND(v0, v1, v2, v3)
v0 ^= mi
# this is the switch fallthrough:
# https://github.com/python/cpython/blob/d1dd6be613381b996b9071443ef081de8e5f3aff/Python/pyhash.c#L390-L400 # noqa: E501
t = types.uint64(0x0)
boffset = idx * 8
ohexefef = types.uint64(0xff)
if src_sz >= 7:
jmp = (6 * 8)
mask = ~types.uint64(ohexefef << jmp)
t = (t & mask) | (types.uint64(grab_byte(src, boffset + 6))
<< jmp)
if src_sz >= 6:
jmp = (5 * 8)
mask = ~types.uint64(ohexefef << jmp)
t = (t & mask) | (types.uint64(grab_byte(src, boffset + 5))
<< jmp)
if src_sz >= 5:
jmp = (4 * 8)
mask = ~types.uint64(ohexefef << jmp)
t = (t & mask) | (types.uint64(grab_byte(src, boffset + 4))
<< jmp)
if src_sz >= 4:
t &= types.uint64(0xffffffff00000000)
for i in range(4):
jmp = i * 8
mask = ~types.uint64(ohexefef << jmp)
t = (t & mask) | (types.uint64(grab_byte(src, boffset + i))
<< jmp)
if src_sz >= 3:
jmp = (2 * 8)
mask = ~types.uint64(ohexefef << jmp)
t = (t & mask) | (types.uint64(grab_byte(src, boffset + 2))
<< jmp)
if src_sz >= 2:
jmp = (1 * 8)
mask = ~types.uint64(ohexefef << jmp)
t = (t & mask) | (types.uint64(grab_byte(src, boffset + 1))
<< jmp)
if src_sz >= 1:
mask = ~(ohexefef)
t = (t & mask) | (types.uint64(grab_byte(src, boffset + 0)))
b |= t
v3 ^= b
v0, v1, v2, v3 = _DOUBLE_ROUND(v0, v1, v2, v3)
v0 ^= b
v2 ^= ohexefef
v0, v1, v2, v3 = _DOUBLE_ROUND(v0, v1, v2, v3)
v0, v1, v2, v3 = _DOUBLE_ROUND(v0, v1, v2, v3)
t = (v0 ^ v1) ^ (v2 ^ v3)
return t