danny/emory
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

chunk/find: don't hard code the buzhash shift

Browse Source
This commit is contained in:
Danny Robson 2021-01-23 06:47:59 +10:00
parent 0028e5f382
commit 6d584b10ec
1 changed files with 3 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
emory/chunk/find.hpp
View File

@ -37,6 +37,7 @@ namespace emory::chunk {
digest_type const mask = ~digest_type (0) >> (sizeof (digest_type) * 8 - p.bits); digest_type const mask = ~digest_type (0) >> (sizeof (digest_type) * 8 - p.bits);
u64 hash_state = 0; u64 hash_state = 0;
static u64 constexpr hash_shift = 1;
auto start = src.begin (); auto start = src.begin ();
// Scan the entire source memory region // Scan the entire source memory region
@ -54,8 +55,8 @@ namespace emory::chunk {
if (cursor < start + p.maximum) { if (cursor < start + p.maximum) {
// Rotate the buzhash state if we haven't hit a marker. // Rotate the buzhash state if we haven't hit a marker.
if (likely (hash_state & mask)) { if (likely (hash_state & mask)) {
hash_state = cruft::rotatel (hash_state, 1) hash_state = cruft::rotatel (hash_state, hash_shift)
^ cruft::rotatel (u64 (*(cursor - p.window)), p.window) ^ cruft::rotatel (u64 (*(cursor - p.window)), p.window * hash_shift)
^ *cursor; ^ *cursor;
continue; continue;
} }