mmh3module.cpp

//-----------------------------------------------------------------------------
// MurmurHash3 was written by Austin Appleby, and is placed in the public
// domain. mmh3 Python module was written by Hajime Senuma,
// and is also placed in the public domain/CC0 1.0.
// The authors hereby disclaim copyright to these source codes.

// To handle 64-bit data; see https://docs.python.org/2.7/c-api/arg.html
#ifndef PY_SSIZE_T_CLEAN
#define PY_SSIZE_T_CLEAN
#endif

#include <stdio.h>
#include <string.h>
#include <Python.h>
#include "MurmurHash3.h"

#if defined(_MSC_VER)
typedef signed __int8 int8_t;
typedef signed __int32 int32_t;
typedef signed __int64 int64_t;
typedef unsigned __int8 uint8_t;
typedef unsigned __int32 uint32_t;
typedef unsigned __int64 uint64_t;
// Other compilers
#else    // defined(_MSC_VER)
#include <stdint.h>
#endif // !defined(_MSC_VER)

static PyObject *
mmh3_hash(PyObject *self, PyObject *args, PyObject *keywds)
{
    const char *target_str;
    Py_ssize_t target_str_len;
    uint32_t seed = 0;
    int32_t result[1];
    long long_result = 0;
    int is_signed = 1;
    
    static char *kwlist[] = {(char *)"key", (char *)"seed",
      (char *)"signed", NULL};
      
#ifndef _MSC_VER
  static uint64_t mask[] = {0x0ffffffff, 0xffffffffffffffff};
#endif

    if (!PyArg_ParseTupleAndKeywords(args, keywds, "s#|IB", kwlist,
        &target_str, &target_str_len, &seed, &is_signed)) {
        return NULL;
    }

    MurmurHash3_x86_32(target_str, target_str_len, seed, result);

#if defined(_MSC_VER)
  /* for Windows envs */
  long_result = result[0];
  if (is_signed == 1) {
    return PyLong_FromLong(long_result);
  } else {
    return PyLong_FromUnsignedLong(long_result);
  }
#else  
  /* for standard envs */
  long_result = result[0] & mask[is_signed];
  return PyLong_FromLong(long_result);
#endif
}

static PyObject *
mmh3_hash_from_buffer(PyObject *self, PyObject *args, PyObject *keywds)
{
    Py_buffer target_buf;
    uint32_t seed = 0;
    int32_t result[1];
    long long_result = 0;
    int is_signed = 1;

    static char *kwlist[] = {(char *)"key", (char *)"seed",
      (char *)"signed", NULL};

#ifndef _MSC_VER
    static uint64_t mask[] = {0x0ffffffff, 0xffffffffffffffff};
#endif

    if (!PyArg_ParseTupleAndKeywords(args, keywds, "s*|IB", kwlist,
                                     &target_buf, &seed, &is_signed)) {
      return NULL;
    }

    MurmurHash3_x86_32(target_buf.buf, target_buf.len, seed, result);

#if defined(_MSC_VER)
    /* for Windows envs */
    long_result = result[0];
    if (is_signed == 1) {
      return PyLong_FromLong(long_result);
    } else {
      return PyLong_FromUnsignedLong(long_result);
    }
#else
    /* for standard envs */
    long_result = result[0] & mask[is_signed];
    return PyLong_FromLong(long_result);
#endif
}

static PyObject *
mmh3_hash64(PyObject *self, PyObject *args, PyObject *keywds)
{
    const char *target_str;
    Py_ssize_t target_str_len;
    uint32_t seed = 0;
    uint64_t result[2];
    char x64arch = 1;
    int is_signed = 1;

    static char *kwlist[] = {(char *)"key", (char *)"seed",
      (char *)"x64arch", (char *)"signed", NULL};

    static char *valflag[] = {(char *) "KK", (char *) "LL"};

    if (!PyArg_ParseTupleAndKeywords(args, keywds, "s#|IBB", kwlist,
        &target_str, &target_str_len, &seed, &x64arch, &is_signed)) {
        return NULL;
    }

    if (x64arch == 1) {
      MurmurHash3_x64_128(target_str, target_str_len, seed, result);
    } else {
      MurmurHash3_x86_128(target_str, target_str_len, seed, result);
    }

    PyObject *retval = Py_BuildValue(valflag[is_signed], result[0], result[1]);
    return retval;
}

static PyObject *
mmh3_hash128(PyObject *self, PyObject *args, PyObject *keywds)
{
    const char *target_str;
    Py_ssize_t target_str_len;
    uint32_t seed = 0;
    uint64_t result[2];
    char x64arch = 1;
    char is_signed = 0;

    static char *kwlist[] = {(char *)"key", (char *)"seed",
      (char *)"x64arch", (char *)"signed", NULL};

    if (!PyArg_ParseTupleAndKeywords(args, keywds, "s#|IBB", kwlist,
        &target_str, &target_str_len, &seed, &x64arch, &is_signed)) {
        return NULL;
    }

    if (x64arch == 1) {
      MurmurHash3_x64_128(target_str, target_str_len, seed, result);
    } else {
      MurmurHash3_x86_128(target_str, target_str_len, seed, result);
    }

    /**
     * _PyLong_FromByteArray is not a part of official Python/C API
     * and can be displaced (although it is practically stable). cf.
     * https://mail.python.org/pipermail/python-list/2006-August/372368.html
     */
    PyObject *retval = _PyLong_FromByteArray((unsigned char *)result, 16, 1, is_signed);      
    
    return retval;
}

static PyObject *
mmh3_hash_bytes(PyObject *self, PyObject *args, PyObject *keywds)
{
    const char *target_str;
    Py_ssize_t target_str_len;
    uint32_t seed = 0;
    uint32_t result[4];
    char x64arch = 1;

    static char *kwlist[] = {(char *)"key", (char *)"seed",
      (char *)"x64arch", NULL};

    if (!PyArg_ParseTupleAndKeywords(args, keywds, "s#|IB", kwlist,
        &target_str, &target_str_len, &seed, &x64arch)) {
        return NULL;
    }

    if (x64arch == 1) {
      MurmurHash3_x64_128(target_str, target_str_len, seed, result);
    } else {
      MurmurHash3_x86_128(target_str, target_str_len, seed, result);
    }

    char bytes[16];
    memcpy(bytes, result, 16);
    return PyBytes_FromStringAndSize(bytes, 16);
}

struct module_state {
  PyObject *error;
};
    
#if PY_MAJOR_VERSION >= 3
#define GETSTATE(m) ((struct module_state*)PyModule_GetState(m))
#else
#define GETSTATE(m) (&_state)
static struct module_state _state;
#endif

static PyMethodDef Mmh3Methods[] = {
    {"hash", (PyCFunction)mmh3_hash, METH_VARARGS | METH_KEYWORDS,
        "hash(key[, seed=0, signed=True]) -> hash value\n Return a 32 bit integer."},
    {"hash_from_buffer", (PyCFunction)mmh3_hash_from_buffer, METH_VARARGS | METH_KEYWORDS,
     "hash_from_buffer(key[, seed=0, signed=True]) -> hash value from a memory buffer\n Return a 32 bit integer. Designed for large memory-views such as numpy arrays."},
    {"hash64", (PyCFunction)mmh3_hash64, METH_VARARGS | METH_KEYWORDS,
        "hash64(key[, seed=0, x64arch=True, signed=True]) -> (hash value 1, hash value 2)\n Return a tuple of two 64 bit integers for a string. Optimized for the x64 bit architecture when x64arch=True, otherwise for x86."},
    {"hash128", (PyCFunction)mmh3_hash128, METH_VARARGS | METH_KEYWORDS,
        "hash128(key[, seed=0, x64arch=True, signed=False]]) -> hash value\n Return a 128 bit long integer. Optimized for the x64 bit architecture when x64arch=True, otherwise for x86."},
    {"hash_bytes", (PyCFunction)mmh3_hash_bytes,
      METH_VARARGS | METH_KEYWORDS,
        "hash_bytes(key[, seed=0, x64arch=True]) -> bytes\n Return a 128 bit hash value as bytes for a string. Optimized for the x64 bit architecture when x64arch=True, otherwise for the x86."},
    {NULL, NULL, 0, NULL}
};

#if PY_MAJOR_VERSION >= 3

static int mmh3_traverse(PyObject *m, visitproc visit, void *arg) {
    Py_VISIT(GETSTATE(m)->error);
    return 0;
}

static int mmh3_clear(PyObject *m) {
    Py_CLEAR(GETSTATE(m)->error);
    return 0;
}

static struct PyModuleDef mmh3module = {
    PyModuleDef_HEAD_INIT,
    "mmh3",
    "mmh3 is a Python front-end to MurmurHash3, a fast and robust hash library created by Austin Appleby (http://code.google.com/p/smhasher/).\n Ported by Hajime Senuma <hajime.senuma@gmail.com>\n Try hash('foobar') or hash('foobar', 1984).\n If you find any bugs, please submit an issue via https://github.com/hajimes/mmh3",
    sizeof(struct module_state),
    Mmh3Methods,
    NULL,
    mmh3_traverse,
    mmh3_clear,
    NULL
};

#define INITERROR return NULL

extern "C" {
PyMODINIT_FUNC
PyInit_mmh3(void)

#else // PY_MAJOR_VERSION >= 3
#define INITERROR return

extern "C" {
void
initmmh3(void)
#endif // PY_MAJOR_VERSION >= 3

{
#if PY_MAJOR_VERSION >= 3
    PyObject *module = PyModule_Create(&mmh3module);
#else
    PyObject *module = Py_InitModule("mmh3", Mmh3Methods);
#endif

    if (module == NULL)
        INITERROR;

    PyModule_AddStringConstant(module, "__version__", "3.0.0");

    struct module_state *st = GETSTATE(module);

    st->error = PyErr_NewException((char *) "mmh3.Error", NULL, NULL);
    if (st->error == NULL) {
        Py_DECREF(module);
        INITERROR;
    }

#if PY_MAJOR_VERSION >= 3
    return module;
#endif
}
} // extern "C"