hash: prepare for user-selectable hash functions

Localize the hash function in bees to a single spot to make it easier
to change later (or at runtime).

Remove some code that was using a property of CRC as an optimization.
The optimization doesn't work for other hash functions, and running the
CRC function takes more CPU time than the optimization saved.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>

src/bees-hash.cc

@@ -1,5 +1,6 @@
 #include "bees.h"
 
+#include "crucible/city.h"
 #include "crucible/crc64.h"
 #include "crucible/string.h"
 
@@ -11,6 +12,12 @@
 using namespace crucible;
 using namespace std;
 
+BeesHash::BeesHash(const uint8_t *ptr, size_t len) :
+	// m_hash(CityHash64(reinterpret_cast<const char *>(ptr), len))
+	m_hash(Digest::CRC::crc64(ptr, len))
+{
+}
+
 ostream &
 operator<<(ostream &os, const BeesHash &bh)
 {