Pure python murmur3 fallback initial implementation
TBD: - Python 3 - Possibly some profiling and optimization
This commit is contained in:
Adam Holmberg
@@ -1,276 +0,0 @@
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/*
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* The majority of this code was taken from the python-smhasher library,
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* which can be found here: https://github.com/phensley/python-smhasher
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*
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* That library is under the MIT license with the following copyright:
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*
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* Copyright (c) 2011 Austin Appleby (Murmur3 routine)
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* Copyright (c) 2011 Patrick Hensley (Python wrapper, packaging)
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* Copyright 2013 DataStax (Minor modifications to match Cassandra's MM3 hashes)
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*
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*/
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#define PY_SSIZE_T_CLEAN 1
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#include <Python.h>
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#include <stdio.h>
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#if PY_VERSION_HEX < 0x02050000
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typedef int Py_ssize_t;
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#define PY_SSIZE_T_MAX INT_MAX
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#define PY_SSIZE_T_MIN INT_MIN
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#endif
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#ifdef PYPY_VERSION
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#define COMPILING_IN_PYPY 1
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#define COMPILING_IN_CPYTHON 0
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#else
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#define COMPILING_IN_PYPY 0
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#define COMPILING_IN_CPYTHON 1
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#endif
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//-----------------------------------------------------------------------------
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// Platform-specific functions and macros
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// Microsoft Visual Studio
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#if defined(_MSC_VER)
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typedef unsigned char uint8_t;
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typedef unsigned long uint32_t;
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typedef unsigned __int64 uint64_t;
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typedef char int8_t;
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typedef long int32_t;
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typedef __int64 int64_t;
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#define FORCE_INLINE __forceinline
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#include <stdlib.h>
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#define ROTL32(x,y) _rotl(x,y)
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#define ROTL64(x,y) _rotl64(x,y)
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#define BIG_CONSTANT(x) (x)
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// Other compilers
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#else // defined(_MSC_VER)
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#include <stdint.h>
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#define FORCE_INLINE inline __attribute__((always_inline))
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inline uint32_t rotl32 ( int32_t x, int8_t r )
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{
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// cast to unsigned for logical right bitshift (to match C* MM3 implementation)
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return (x << r) | ((int32_t) (((uint32_t) x) >> (32 - r)));
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}
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inline int64_t rotl64 ( int64_t x, int8_t r )
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{
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// cast to unsigned for logical right bitshift (to match C* MM3 implementation)
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return (x << r) | ((int64_t) (((uint64_t) x) >> (64 - r)));
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}
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#define ROTL32(x,y) rotl32(x,y)
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#define ROTL64(x,y) rotl64(x,y)
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#define BIG_CONSTANT(x) (x##LL)
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#endif // !defined(_MSC_VER)
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//-----------------------------------------------------------------------------
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// Block read - if your platform needs to do endian-swapping or can only
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// handle aligned reads, do the conversion here
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// TODO 32bit?
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FORCE_INLINE int64_t getblock ( const int64_t * p, int i )
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{
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return p[i];
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}
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//-----------------------------------------------------------------------------
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// Finalization mix - force all bits of a hash block to avalanche
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FORCE_INLINE int64_t fmix ( int64_t k )
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{
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// cast to unsigned for logical right bitshift (to match C* MM3 implementation)
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k ^= ((uint64_t) k) >> 33;
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k *= BIG_CONSTANT(0xff51afd7ed558ccd);
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k ^= ((uint64_t) k) >> 33;
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k *= BIG_CONSTANT(0xc4ceb9fe1a85ec53);
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k ^= ((uint64_t) k) >> 33;
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return k;
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}
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int64_t MurmurHash3_x64_128 (const void * key, const int len,
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const uint32_t seed)
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{
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const int8_t * data = (const int8_t*)key;
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const int nblocks = len / 16;
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int64_t h1 = seed;
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int64_t h2 = seed;
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int64_t c1 = BIG_CONSTANT(0x87c37b91114253d5);
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int64_t c2 = BIG_CONSTANT(0x4cf5ad432745937f);
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int64_t k1 = 0;
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int64_t k2 = 0;
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const int64_t * blocks = (const int64_t *)(data);
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const int8_t * tail = (const int8_t*)(data + nblocks*16);
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//----------
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// body
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int i;
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for(i = 0; i < nblocks; i++)
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{
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int64_t k1 = getblock(blocks,i*2+0);
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int64_t k2 = getblock(blocks,i*2+1);
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k1 *= c1; k1 = ROTL64(k1,31); k1 *= c2; h1 ^= k1;
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h1 = ROTL64(h1,27); h1 += h2; h1 = h1*5+0x52dce729;
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k2 *= c2; k2 = ROTL64(k2,33); k2 *= c1; h2 ^= k2;
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h2 = ROTL64(h2,31); h2 += h1; h2 = h2*5+0x38495ab5;
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}
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//----------
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// tail
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switch(len & 15)
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{
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case 15: k2 ^= ((int64_t) (tail[14])) << 48;
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case 14: k2 ^= ((int64_t) (tail[13])) << 40;
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case 13: k2 ^= ((int64_t) (tail[12])) << 32;
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case 12: k2 ^= ((int64_t) (tail[11])) << 24;
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case 11: k2 ^= ((int64_t) (tail[10])) << 16;
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case 10: k2 ^= ((int64_t) (tail[ 9])) << 8;
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case 9: k2 ^= ((int64_t) (tail[ 8])) << 0;
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k2 *= c2; k2 = ROTL64(k2,33); k2 *= c1; h2 ^= k2;
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case 8: k1 ^= ((int64_t) (tail[ 7])) << 56;
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case 7: k1 ^= ((int64_t) (tail[ 6])) << 48;
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case 6: k1 ^= ((int64_t) (tail[ 5])) << 40;
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case 5: k1 ^= ((int64_t) (tail[ 4])) << 32;
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case 4: k1 ^= ((int64_t) (tail[ 3])) << 24;
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case 3: k1 ^= ((int64_t) (tail[ 2])) << 16;
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case 2: k1 ^= ((int64_t) (tail[ 1])) << 8;
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case 1: k1 ^= ((int64_t) (tail[ 0])) << 0;
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k1 *= c1; k1 = ROTL64(k1,31); k1 *= c2; h1 ^= k1;
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};
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//----------
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// finalization
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h1 ^= len; h2 ^= len;
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h1 += h2;
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h2 += h1;
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h1 = fmix(h1);
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h2 = fmix(h2);
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h1 += h2;
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h2 += h1;
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return h1;
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}
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struct module_state {
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PyObject *error;
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};
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// pypy3 doesn't have GetState yet.
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#if COMPILING_IN_CPYTHON && PY_MAJOR_VERSION >= 3
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#define GETSTATE(m) ((struct module_state*)PyModule_GetState(m))
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#else
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#define GETSTATE(m) (&_state)
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static struct module_state _state;
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#endif
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static PyObject *
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murmur3(PyObject *self, PyObject *args)
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{
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const char *key;
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Py_ssize_t len;
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uint32_t seed = 0;
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int64_t result = 0;
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if (!PyArg_ParseTuple(args, "s#|I", &key, &len, &seed)) {
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return NULL;
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}
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// TODO handle x86 version?
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result = MurmurHash3_x64_128((void *)key, len, seed);
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return (PyObject *) PyLong_FromLongLong(result);
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}
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static PyMethodDef murmur3_methods[] = {
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{"murmur3", murmur3, METH_VARARGS, "Make an x64 murmur3 64-bit hash value"},
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{NULL, NULL, 0, NULL}
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};
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#if PY_MAJOR_VERSION >= 3
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static int murmur3_traverse(PyObject *m, visitproc visit, void *arg) {
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Py_VISIT(GETSTATE(m)->error);
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return 0;
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}
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static int murmur3_clear(PyObject *m) {
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Py_CLEAR(GETSTATE(m)->error);
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return 0;
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}
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static struct PyModuleDef moduledef = {
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PyModuleDef_HEAD_INIT,
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"murmur3",
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NULL,
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sizeof(struct module_state),
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murmur3_methods,
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NULL,
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murmur3_traverse,
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murmur3_clear,
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NULL
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};
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#define INITERROR return NULL
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PyObject *
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PyInit_murmur3(void)
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#else
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#define INITERROR return
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void
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initmurmur3(void)
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#endif
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{
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#if PY_MAJOR_VERSION >= 3
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PyObject *module = PyModule_Create(&moduledef);
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#else
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PyObject *module = Py_InitModule("murmur3", murmur3_methods);
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#endif
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struct module_state *st = NULL;
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if (module == NULL)
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INITERROR;
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st = GETSTATE(module);
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st->error = PyErr_NewException("murmur3.Error", NULL, NULL);
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if (st->error == NULL) {
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Py_DECREF(module);
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INITERROR;
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}
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#if PY_MAJOR_VERSION >= 3
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return module;
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#endif
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}
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119
cassandra/murmur3.py
Normal file
119
cassandra/murmur3.py
Normal file
@@ -0,0 +1,119 @@
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import six
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from six.moves import range
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if six.PY3:
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def blocks_and_tail(data, nblocks):
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# use array 'q' here?
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pass
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else:
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import struct
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def body_and_tail(data):
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l = len(data)
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nblocks = l // 16
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tail = l % 16
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if nblocks:
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return struct.unpack_from('qq' * nblocks, data), struct.unpack_from('b' * tail, data, -tail), l
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# TODO: try unpack generator vs built formatter
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# TODO: try unpack pairs in generator ^^
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else:
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return tuple(), struct.unpack_from('b' * tail, data, -tail), l
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INT64_MAX = 2 ** 63 - 1
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# TODO: better if these are int or long constants?
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INT64_MIN = -INT64_MAX - 1
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INT64_OVF_OFFSET = INT64_MAX + 1
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INT64_OVF_DIV = 2 * INT64_OVF_OFFSET
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def rotl64(x, r):
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mask = 2 ** r - 1
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rotated = (x << r) | ((x >> 64 - r) & mask)
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return rotated
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def fmix(k):
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k ^= (k >> 33) & 0x7fffffff
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k *= 0xff51afd7ed558ccd
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k ^= (k >> 33) & 0x7fffffff
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k *= 0xc4ceb9fe1a85ec53
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k ^= (k >> 33) & 0x7fffffff
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return k
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def truncate_int64(x):
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if not INT64_MIN <= x <= INT64_MAX:
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x = (x + INT64_OVF_OFFSET) % INT64_OVF_DIV - INT64_OVF_OFFSET
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return x
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def _murmur3(data):
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h1 = h2 = 0
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c1 = -8663945395140668459 # 0x87c37b91114253d5
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c2 = 0x4cf5ad432745937f
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body, tail, total_len = body_and_tail(data)
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# body
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for i in range(0, len(body), 2):
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k1 = body[i]
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k2 = body[i + 1]
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k1 *= c1
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k1 = rotl64(k1, 31)
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k1 *= c2
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h1 ^= k1
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h1 = rotl64(h1, 27)
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h1 += h2
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h1 = h1 * 5 + 0x52dce729
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k2 *= c2
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k2 = rotl64(k2, 33)
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k2 *= c1
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h2 ^= k2
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h2 = rotl64(h2, 31)
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h2 += h1
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h2 = h2 * 5 + 0x38495ab5
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# tail
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k1 = k2 = 0
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len_tail = len(tail)
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if len_tail > 8:
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for i in range(len_tail - 1, 7, -1):
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k2 ^= tail[i] << (i - 8) * 8
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k2 *= c2
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k2 = rotl64(k2, 33)
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k2 *= c1
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h2 ^= k2
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if len_tail:
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for i in range(min(7, len_tail - 1), -1, -1):
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k1 ^= tail[i] << i * 8
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k1 *= c1
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k1 = rotl64(k1, 31)
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k1 *= c2
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h1 ^= k1
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# finalization
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h1 ^= total_len
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h2 ^= total_len
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h1 += h2
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h2 += h1
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h1 = fmix(h1)
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h2 = fmix(h2)
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h1 += h2
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return truncate_int64(h1)
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try:
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from cassandra.cmurmur3 import murmur3
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except ImportError:
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murmur3 = _murmur3
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4
setup.py
4
setup.py
@@ -121,8 +121,8 @@ class BuildFailed(Exception):
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self.ext = ext
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murmur3_ext = Extension('cassandra.murmur3',
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sources=['cassandra/murmur3.c'])
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murmur3_ext = Extension('cassandra.cmurmur3',
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sources=['cassandra/cmurmur3.c'])
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libev_ext = Extension('cassandra.io.libevwrapper',
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sources=['cassandra/io/libevwrapper.c'],
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Block a user