Message 119034 - Python tracker (original) (raw)

On Mon, Oct 18, 2010 at 11:27 AM, Antoine Pitrou <report@bugs.python.org> wrote: ..

The benefit, though is that hash computations can be performed natively on the hash values without casting to an unrelated type.

I don't understand what you mean by "native" and "unrelated". Signed integers are not less native than unsigned ones.

Sorry, I could have been clearer indeed. Consider the following code:

static Py_hash_t long_hash(PyLongObject *v) { unsigned long x; ... x = x * sign; if (x == (unsigned long)-1) x = (unsigned long)-2; return (Py_hash_t)x; }

Wouldn't it be cleaner if x was the same type as hash? Note that unsigned long is now wrong. What is needed is "unsigned integer type of the same size as Py_hash_t." If Py_hash_t has to stay signed, I think we should at least not rely of sizeof(Py_hash_t) to always remain the same as sizeof(size_t).