[Python-checkins] fix my byte-swapping implementation (#4772)
Benjamin Peterson
webhook-mailer at python.org
Sat Dec 9 15:19:00 EST 2017
https://github.com/python/cpython/commit/83620773eef7380178ba84217a26fe22d1636474
commit: 83620773eef7380178ba84217a26fe22d1636474
branch: master
author: Benjamin Peterson <benjamin at python.org>
committer: GitHub <noreply at github.com>
date: 2017-12-09T12:18:56-08:00
summary:
fix my byte-swapping implementation (#4772)
files:
M Python/import.c
diff --git a/Python/import.c b/Python/import.c
index b2d751111bf..892f3d1c6e4 100644
--- a/Python/import.c
+++ b/Python/import.c
@@ -2197,21 +2197,21 @@ static PyObject *
_imp_source_hash_impl(PyObject *module, long key, Py_buffer *source)
/*[clinic end generated code: output=edb292448cf399ea input=9aaad1e590089789]*/
{
- uint64_t hash = _Py_KeyedHash((uint64_t)key, source->buf, source->len);
+ union {
+ uint64_t x;
+ char data[sizeof(uint64_t)];
+ } hash;
+ hash.x = _Py_KeyedHash((uint64_t)key, source->buf, source->len);
#if !PY_LITTLE_ENDIAN
// Force to little-endian. There really ought to be a succinct standard way
// to do this.
- union {
- uint64_t x;
- unsigned char data[sizeof(uint64_t)];
- } pun;
- pun.x = hash;
- for (size_t i = 0; i < sizeof(pun.data); i++) {
- pun.data[sizeof(pun.data) - i - 1] = pun.data[i];
+ for (size_t i = 0; i < sizeof(hash.data)/2; i++) {
+ char tmp = hash.data[i];
+ hash.data[i] = hash.data[sizeof(hash.data) - i - 1];
+ hash.data[sizeof(hash.data) - i - 1] = tmp;
}
- hash = pun.x;
#endif
- return PyBytes_FromStringAndSize((const char *)&hash, sizeof(hash));
+ return PyBytes_FromStringAndSize(hash.data, sizeof(hash.data));
}
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