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authorJeremy Rubin <jeremy.l.rubin@gmail.com>2017-02-19 13:11:44 -0500
committerJeremy Rubin <jeremy.l.rubin@gmail.com>2017-07-08 13:33:01 -0700
commit6896dbf16996402cc9820e345605716a3dc60482 (patch)
tree753e7fd85d98f59024dc3059e5eb3ed0d48724d7
parent96f2119e6c391617f0c7f27ce5af44604a7af937 (diff)
Cleanup (safe, it was checked) subscript[0] in MurmurHash3 (and cleanup MurmurHash3 to be more clear).
-rw-r--r--src/hash.cpp43
1 files changed, 20 insertions, 23 deletions
diff --git a/src/hash.cpp b/src/hash.cpp
index b361c90d16..5a15600be5 100644
--- a/src/hash.cpp
+++ b/src/hash.cpp
@@ -17,36 +17,34 @@ unsigned int MurmurHash3(unsigned int nHashSeed, const std::vector<unsigned char
{
// The following is MurmurHash3 (x86_32), see http://code.google.com/p/smhasher/source/browse/trunk/MurmurHash3.cpp
uint32_t h1 = nHashSeed;
- if (vDataToHash.size() > 0)
- {
- const uint32_t c1 = 0xcc9e2d51;
- const uint32_t c2 = 0x1b873593;
+ const uint32_t c1 = 0xcc9e2d51;
+ const uint32_t c2 = 0x1b873593;
- const int nblocks = vDataToHash.size() / 4;
+ const int nblocks = vDataToHash.size() / 4;
- //----------
- // body
- const uint8_t* blocks = &vDataToHash[0] + nblocks * 4;
+ //----------
+ // body
+ const uint8_t* blocks = vDataToHash.data();
- for (int i = -nblocks; i; i++) {
- uint32_t k1 = ReadLE32(blocks + i*4);
+ for (int i = 0; i < nblocks; ++i) {
+ uint32_t k1 = ReadLE32(blocks + i*4);
- k1 *= c1;
- k1 = ROTL32(k1, 15);
- k1 *= c2;
+ k1 *= c1;
+ k1 = ROTL32(k1, 15);
+ k1 *= c2;
- h1 ^= k1;
- h1 = ROTL32(h1, 13);
- h1 = h1 * 5 + 0xe6546b64;
- }
+ h1 ^= k1;
+ h1 = ROTL32(h1, 13);
+ h1 = h1 * 5 + 0xe6546b64;
+ }
- //----------
- // tail
- const uint8_t* tail = (const uint8_t*)(&vDataToHash[0] + nblocks * 4);
+ //----------
+ // tail
+ const uint8_t* tail = vDataToHash.data() + nblocks * 4;
- uint32_t k1 = 0;
+ uint32_t k1 = 0;
- switch (vDataToHash.size() & 3) {
+ switch (vDataToHash.size() & 3) {
case 3:
k1 ^= tail[2] << 16;
case 2:
@@ -57,7 +55,6 @@ unsigned int MurmurHash3(unsigned int nHashSeed, const std::vector<unsigned char
k1 = ROTL32(k1, 15);
k1 *= c2;
h1 ^= k1;
- }
}
//----------