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author | Jeremy Rubin <jeremy.l.rubin@gmail.com> | 2017-02-19 13:11:44 -0500 |
---|---|---|
committer | Jeremy Rubin <jeremy.l.rubin@gmail.com> | 2017-07-08 13:33:01 -0700 |
commit | 6896dbf16996402cc9820e345605716a3dc60482 (patch) | |
tree | 753e7fd85d98f59024dc3059e5eb3ed0d48724d7 | |
parent | 96f2119e6c391617f0c7f27ce5af44604a7af937 (diff) |
Cleanup (safe, it was checked) subscript[0] in MurmurHash3 (and cleanup MurmurHash3 to be more clear).
-rw-r--r-- | src/hash.cpp | 43 |
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; - } } //---------- |