Expose MurmurHash3 to Python land, remove cast

khmer/__init__.py

@@ -28,6 +28,9 @@
 from khmer._khmer import reverse_hash  # tests/test_functions.py
 # tests/counting_single.py
 
+from khmer._khmer import hash_murmur3        # tests/test_functions.py
+from khmer._khmer import hash_no_rc_murmur3  # tests/test_functions.py
+
 from khmer._khmer import get_version_cpp as __version_cpp__
 # tests/test_version.py
 

khmer/_khmermodule.cc

@@ -4467,6 +4467,28 @@ static PyObject * reverse_hash(PyObject * self, PyObject * args)
     return PyString_FromString(_revhash(val, ksize).c_str());
 }
 
+static PyObject * murmur3_forward_hash(PyObject * self, PyObject * args)
+{
+    const char * kmer;
+
+    if (!PyArg_ParseTuple(args, "s", &kmer)) {
+        return NULL;
+    }
+
+    return PyLong_FromUnsignedLongLong(_hash_murmur(kmer));
+}
+
+static PyObject * murmur3_forward_hash_no_rc(PyObject * self, PyObject * args)
+{
+    const char * kmer;
+
+    if (!PyArg_ParseTuple(args, "s", &kmer)) {
+        return NULL;
+    }
+
+    return PyLong_FromUnsignedLongLong(_hash_murmur_forward(kmer));
+}
+
 static PyObject * set_reporting_callback(PyObject * self, PyObject * args)
 {
     PyObject * o;
@@ -4543,6 +4565,20 @@ static PyMethodDef KhmerMethods[] = {
         "reverse_hash",     reverse_hash,
         METH_VARARGS,       "",
     },
+    {
+        "hash_murmur3",
+        murmur3_forward_hash,
+        METH_VARARGS,
+        "Calculate the hash value of a k-mer using MurmurHash3 "
+        "(with reverse complement)",
+    },
+    {
+        "hash_no_rc_murmur3",
+        murmur3_forward_hash_no_rc,
+        METH_VARARGS,
+        "Calculate the hash value of a k-mer using MurmurHash3 "
+        "(no reverse complement)",
+    },
     {
         "set_reporting_callback",   set_reporting_callback,
         METH_VARARGS,       "",

lib/kmer_hash.cc

@@ -137,11 +137,11 @@ HashIntoType _hash_murmur(const std::string& kmer,
 {
     HashIntoType out[2];
     uint32_t seed = 0;
-    MurmurHash3_x64_128((void *)kmer.c_str(), (int)kmer.size(), seed, &out);
+    MurmurHash3_x64_128((void *)kmer.c_str(), kmer.size(), seed, &out);
     h = out[0];
 
     std::string rev = khmer::_revcomp(kmer);
-    MurmurHash3_x64_128((void *)rev.c_str(), (int)rev.size(), seed, &out);
+    MurmurHash3_x64_128((void *)rev.c_str(), rev.size(), seed, &out);
     r = out[0];
 
     return h ^ r;

tests/test_functions.py

@@ -45,6 +45,27 @@ def test_reverse_hash():
     assert s == "GGGG"
 
 
+def test_hash_murmur3():
+    assert khmer.hash_murmur3('AAAA') == 526240128537019279
+    assert khmer.hash_murmur3('TTTT') == 526240128537019279
+    assert khmer.hash_murmur3('CCCC') == 14391997331386449225
+    assert khmer.hash_murmur3('GGGG') == 14391997331386449225
+
+
+def test_hash_no_rc_murmur3():
+    h = khmer.hash_no_rc_murmur3('AAAA')
+    assert h == 5231866503566620412, h
+
+    h = khmer.hash_no_rc_murmur3('TTTT')
+    assert h == 5753003579327329651, h
+
+    h = khmer.hash_no_rc_murmur3('CCCC')
+    assert h == 3789793362494378039, h
+
+    h = khmer.hash_no_rc_murmur3('GGGG')
+    assert h == 17519752047064575358, h
+
+
 def test_get_primes():
     primes = khmer.get_n_primes_near_x(7, 20)