Coverage for local/lib/python2.7/site-packages/sage/misc/fast_methods.pxd : 71%

cdef extern from "Python.h": 

cdef size_t SIZEOF_VOID_P 

cdef class FastHashable_class: 

cdef Py_ssize_t _hash 

cdef inline long hash_by_id(void * p): 

r""" 

This function is a copy paste from the default Python hash function. 

""" 

cdef long x 

cdef size_t y = <size_t>p 

# bottom 3 or 4 bits are likely to be 0; rotate y by 4 to avoid 

# excessive hash collisions for dicts and sets 

y = (y >> 4) | (y << (8 * SIZEOF_VOID_P - 4)) 

x = <long>y 

if x == -1: 

x = -2 

return x