from cpython cimport PyBytes_AsString
#from cpython cimport PyByteArray_AsString # cython still not exports that
cdef extern from "Python.h":
char* PyByteArray_AsString(bytearray ba) except NULL
from libc.stdint cimport uint32_t, uint64_t, uintmax_t
def _websocket_mask_cython(object mask, object data):
"""Note, this function mutates its `data` argument
"""
cdef:
Py_ssize_t data_len, i
# bit operations on signed integers are implementation-specific
unsigned char * in_buf
const unsigned char * mask_buf
uint32_t uint32_msk
uint64_t uint64_msk
assert len(mask) == 4
if not isinstance(mask, bytes):
mask = bytes(mask)
if isinstance(data, bytearray):
data = <bytearray>data
else:
data = bytearray(data)
data_len = len(data)
in_buf = <unsigned char*>PyByteArray_AsString(data)
mask_buf = <const unsigned char*>PyBytes_AsString(mask)
uint32_msk = (<uint32_t*>mask_buf)[0]
# TODO: align in_data ptr to achieve even faster speeds
# does it need in python ?! malloc() always aligns to sizeof(long) bytes
if sizeof(size_t) >= 8:
uint64_msk = uint32_msk
uint64_msk = (uint64_msk << 32) | uint32_msk
while data_len >= 8:
(<uint64_t*>in_buf)[0] ^= uint64_msk
in_buf += 8
data_len -= 8
while data_len >= 4:
(<uint32_t*>in_buf)[0] ^= uint32_msk
in_buf += 4
data_len -= 4
for i in range(0, data_len):
in_buf[i] ^= mask_buf[i]
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