diff options
Diffstat (limited to 'src/fns.c')
| -rw-r--r-- | src/fns.c | 34 |
1 files changed, 15 insertions, 19 deletions
diff --git a/src/fns.c b/src/fns.c index 7ab2e8f1a03..bd4afa0c4e9 100644 --- a/src/fns.c +++ b/src/fns.c @@ -4599,33 +4599,29 @@ sweep_weak_table (struct Lisp_Hash_Table *h, bool remove_entries_p) EMACS_UINT hash_string (char const *ptr, ptrdiff_t len) { - EMACS_UINT const *p = (EMACS_UINT const *) ptr; - EMACS_UINT const *end = (EMACS_UINT const *) (ptr + len); + char const *p = ptr; + char const *end = ptr + len; EMACS_UINT hash = len; /* At most 8 steps. We could reuse SXHASH_MAX_LEN, of course, * but dividing by 8 is cheaper. */ - ptrdiff_t step = 1 + ((end - p) >> 3); + ptrdiff_t step = sizeof hash + ((end - p) >> 3); - /* Beware: `end` might be unaligned, so `p < end` is not always the same - * as `p <= end - 1`. */ - while (p <= end - 1) + while (p + sizeof hash <= end) { - EMACS_UINT c = *p; + EMACS_UINT c; + /* We presume that the compiler will replace this `memcpy` with + a single load/move instruction when applicable. */ + memcpy (&c, p, sizeof hash); p += step; hash = sxhash_combine (hash, c); } - if (p < end) - { /* A few last bytes remain (smaller than an EMACS_UINT). */ - /* FIXME: We could do this without a loop, but it'd require - endian-dependent code :-( */ - char const *p1 = (char const *)p; - char const *end1 = (char const *)end; - do - { - unsigned char c = *p1++; - hash = sxhash_combine (hash, c); - } - while (p1 < end1); + /* A few last bytes may remain (smaller than an EMACS_UINT). */ + /* FIXME: We could do this without a loop, but it'd require + endian-dependent code :-( */ + while (p < end) + { + unsigned char c = *p++; + hash = sxhash_combine (hash, c); } return hash; |