Ejemplo n.º 1
0
/*
 * Recursively examines the object to determine an appropriate dtype
 * to use for converting to an ndarray.
 *
 * 'obj' is the object to be converted to an ndarray.
 *
 * 'maxdims' is the maximum recursion depth.
 *
 * 'out_dtype' should be either NULL or a minimal starting dtype when
 * the function is called. It is updated with the results of type
 * promotion. This dtype does not get updated when processing NA objects.
 * This is reset to NULL on failure.
 *
 * Returns 0 on success, -1 on failure.
 */
 NPY_NO_EXPORT int
PyArray_DTypeFromObject(PyObject *obj, int maxdims, PyArray_Descr **out_dtype)
{
    int res;

    res = PyArray_DTypeFromObjectHelper(obj, maxdims, out_dtype, 0);
    if (res == RETRY_WITH_STRING) {
        res = PyArray_DTypeFromObjectHelper(obj, maxdims,
                                            out_dtype, NPY_STRING);
        if (res == RETRY_WITH_UNICODE) {
            res = PyArray_DTypeFromObjectHelper(obj, maxdims,
                                                out_dtype, NPY_UNICODE);
        }
    }
    else if (res == RETRY_WITH_UNICODE) {
        res = PyArray_DTypeFromObjectHelper(obj, maxdims,
                                            out_dtype, NPY_UNICODE);
    }
    return res;
}
Ejemplo n.º 2
0
NPY_NO_EXPORT int
PyArray_DTypeFromObjectHelper(PyObject *obj, int maxdims,
                              PyArray_Descr **out_dtype, int string_type)
{
    int i, size;
    PyArray_Descr *dtype = NULL;
    PyObject *ip;
    Py_buffer buffer_view;

    /* Check if it's an ndarray */
    if (PyArray_Check(obj)) {
        dtype = PyArray_DESCR((PyArrayObject *)obj);
        Py_INCREF(dtype);
        goto promote_types;
    }

    /* See if it's a python None */
    if (obj == Py_None) {
        dtype = PyArray_DescrFromType(NPY_OBJECT);
        if (dtype == NULL) {
            goto fail;
        }
        Py_INCREF(dtype);
        goto promote_types;
    }
    /* Check if it's a NumPy scalar */
    else if (PyArray_IsScalar(obj, Generic)) {
        if (!string_type) {
            dtype = PyArray_DescrFromScalar(obj);
            if (dtype == NULL) {
                goto fail;
            }
        }
        else {
            int itemsize;
            PyObject *temp;

            if (string_type == NPY_STRING) {
                if ((temp = PyObject_Str(obj)) == NULL) {
                    return -1;
                }
#if defined(NPY_PY3K)
    #if PY_VERSION_HEX >= 0x03030000
                itemsize = PyUnicode_GetLength(temp);
    #else
                itemsize = PyUnicode_GET_SIZE(temp);
    #endif
#else
                itemsize = PyString_GET_SIZE(temp);
#endif
            }
            else if (string_type == NPY_UNICODE) {
#if defined(NPY_PY3K)
                if ((temp = PyObject_Str(obj)) == NULL) {
#else
                if ((temp = PyObject_Unicode(obj)) == NULL) {
#endif
                    return -1;
                }
                itemsize = PyUnicode_GET_DATA_SIZE(temp);
#ifndef Py_UNICODE_WIDE
                itemsize <<= 1;
#endif
            }
            else {
                goto fail;
            }
            Py_DECREF(temp);
            if (*out_dtype != NULL &&
                    (*out_dtype)->type_num == string_type &&
                    (*out_dtype)->elsize >= itemsize) {
                return 0;
            }
            dtype = PyArray_DescrNewFromType(string_type);
            if (dtype == NULL) {
                goto fail;
            }
            dtype->elsize = itemsize;
        }
        goto promote_types;
    }

    /* Check if it's a Python scalar */
    dtype = _array_find_python_scalar_type(obj);
    if (dtype != NULL) {
        if (string_type) {
            int itemsize;
            PyObject *temp;

            if (string_type == NPY_STRING) {
                if ((temp = PyObject_Str(obj)) == NULL) {
                    return -1;
                }
#if defined(NPY_PY3K)
    #if PY_VERSION_HEX >= 0x03030000
                itemsize = PyUnicode_GetLength(temp);
    #else
                itemsize = PyUnicode_GET_SIZE(temp);
    #endif
#else
                itemsize = PyString_GET_SIZE(temp);
#endif
            }
            else if (string_type == NPY_UNICODE) {
#if defined(NPY_PY3K)
                if ((temp = PyObject_Str(obj)) == NULL) {
#else
                if ((temp = PyObject_Unicode(obj)) == NULL) {
#endif
                    return -1;
                }
                itemsize = PyUnicode_GET_DATA_SIZE(temp);
#ifndef Py_UNICODE_WIDE
                itemsize <<= 1;
#endif
            }
            else {
                goto fail;
            }
            Py_DECREF(temp);
            if (*out_dtype != NULL &&
                    (*out_dtype)->type_num == string_type &&
                    (*out_dtype)->elsize >= itemsize) {
                return 0;
            }
            dtype = PyArray_DescrNewFromType(string_type);
            if (dtype == NULL) {
                goto fail;
            }
            dtype->elsize = itemsize;
        }
        goto promote_types;
    }

    /* Check if it's an ASCII string */
    if (PyBytes_Check(obj)) {
        int itemsize = PyString_GET_SIZE(obj);

        /* If it's already a big enough string, don't bother type promoting */
        if (*out_dtype != NULL &&
                        (*out_dtype)->type_num == NPY_STRING &&
                        (*out_dtype)->elsize >= itemsize) {
            return 0;
        }
        dtype = PyArray_DescrNewFromType(NPY_STRING);
        if (dtype == NULL) {
            goto fail;
        }
        dtype->elsize = itemsize;
        goto promote_types;
    }

    /* Check if it's a Unicode string */
    if (PyUnicode_Check(obj)) {
        int itemsize = PyUnicode_GET_DATA_SIZE(obj);
#ifndef Py_UNICODE_WIDE
        itemsize <<= 1;
#endif

        /*
         * If it's already a big enough unicode object,
         * don't bother type promoting
         */
        if (*out_dtype != NULL &&
                        (*out_dtype)->type_num == NPY_UNICODE &&
                        (*out_dtype)->elsize >= itemsize) {
            return 0;
        }
        dtype = PyArray_DescrNewFromType(NPY_UNICODE);
        if (dtype == NULL) {
            goto fail;
        }
        dtype->elsize = itemsize;
        goto promote_types;
    }

    /* PEP 3118 buffer interface */
    if (PyObject_CheckBuffer(obj) == 1) {
        memset(&buffer_view, 0, sizeof(Py_buffer));
        if (PyObject_GetBuffer(obj, &buffer_view,
                               PyBUF_FORMAT|PyBUF_STRIDES) == 0 ||
            PyObject_GetBuffer(obj, &buffer_view, PyBUF_FORMAT) == 0) {

            PyErr_Clear();
            dtype = _descriptor_from_pep3118_format(buffer_view.format);
            PyBuffer_Release(&buffer_view);
            if (dtype) {
                goto promote_types;
            }
        }
        else if (PyObject_GetBuffer(obj, &buffer_view, PyBUF_STRIDES) == 0 ||
                 PyObject_GetBuffer(obj, &buffer_view, PyBUF_SIMPLE) == 0) {

            PyErr_Clear();
            dtype = PyArray_DescrNewFromType(NPY_VOID);
            dtype->elsize = buffer_view.itemsize;
            PyBuffer_Release(&buffer_view);
            goto promote_types;
        }
        else {
            PyErr_Clear();
        }
    }

    /* The array interface */
    ip = PyArray_GetAttrString_SuppressException(obj, "__array_interface__");
    if (ip != NULL) {
        if (PyDict_Check(ip)) {
            PyObject *typestr;
#if defined(NPY_PY3K)
            PyObject *tmp = NULL;
#endif
            typestr = PyDict_GetItemString(ip, "typestr");
#if defined(NPY_PY3K)
            /* Allow unicode type strings */
            if (PyUnicode_Check(typestr)) {
                tmp = PyUnicode_AsASCIIString(typestr);
                typestr = tmp;
            }
#endif
            if (typestr && PyBytes_Check(typestr)) {
                dtype =_array_typedescr_fromstr(PyBytes_AS_STRING(typestr));
#if defined(NPY_PY3K)
                if (tmp == typestr) {
                    Py_DECREF(tmp);
                }
#endif
                Py_DECREF(ip);
                if (dtype == NULL) {
                    goto fail;
                }
                goto promote_types;
            }
        }
        Py_DECREF(ip);
    }

    /* The array struct interface */
    ip = PyArray_GetAttrString_SuppressException(obj, "__array_struct__");
    if (ip != NULL) {
        PyArrayInterface *inter;
        char buf[40];

        if (NpyCapsule_Check(ip)) {
            inter = (PyArrayInterface *)NpyCapsule_AsVoidPtr(ip);
            if (inter->two == 2) {
                PyOS_snprintf(buf, sizeof(buf),
                        "|%c%d", inter->typekind, inter->itemsize);
                dtype = _array_typedescr_fromstr(buf);
                Py_DECREF(ip);
                if (dtype == NULL) {
                    goto fail;
                }
                goto promote_types;
            }
        }
        Py_DECREF(ip);
    }

    /* The old buffer interface */
#if !defined(NPY_PY3K)
    if (PyBuffer_Check(obj)) {
        dtype = PyArray_DescrNewFromType(NPY_VOID);
        if (dtype == NULL) {
            goto fail;
        }
        dtype->elsize = Py_TYPE(obj)->tp_as_sequence->sq_length(obj);
        PyErr_Clear();
        goto promote_types;
    }
#endif

    /* The __array__ attribute */
    ip = PyArray_GetAttrString_SuppressException(obj, "__array__");
    if (ip != NULL) {
        Py_DECREF(ip);
        ip = PyObject_CallMethod(obj, "__array__", NULL);
        if(ip && PyArray_Check(ip)) {
            dtype = PyArray_DESCR((PyArrayObject *)ip);
            Py_INCREF(dtype);
            Py_DECREF(ip);
            goto promote_types;
        }
        Py_XDECREF(ip);
        if (PyErr_Occurred()) {
            goto fail;
        }
    }

    /* Not exactly sure what this is about... */
#if !defined(NPY_PY3K)
    if (PyInstance_Check(obj)) {
        dtype = _use_default_type(obj);
        if (dtype == NULL) {
            goto fail;
        }
        else {
            goto promote_types;
        }
    }
#endif

    /*
     * If we reached the maximum recursion depth without hitting one
     * of the above cases, the output dtype should be OBJECT
     */
    if (maxdims == 0 || !PySequence_Check(obj)) {
        if (*out_dtype == NULL || (*out_dtype)->type_num != NPY_OBJECT) {
            Py_XDECREF(*out_dtype);
            *out_dtype = PyArray_DescrFromType(NPY_OBJECT);
            if (*out_dtype == NULL) {
                return -1;
            }
        }
        return 0;
    }

    /* Recursive case */
    size = PySequence_Size(obj);
    if (size < 0) {
        goto fail;
    }
    /* Recursive call for each sequence item */
    for (i = 0; i < size; ++i) {
        int res;
        ip = PySequence_GetItem(obj, i);
        if (ip == NULL) {
            goto fail;
        }
        res = PyArray_DTypeFromObjectHelper(ip, maxdims - 1,
                                            out_dtype, string_type);
        if (res < 0) {
            Py_DECREF(ip);
            goto fail;
        }
        else if (res > 0) {
            Py_DECREF(ip);
            return res;
        }
        Py_DECREF(ip);
    }

    return 0;


promote_types:
    /* Set 'out_dtype' if it's NULL */
    if (*out_dtype == NULL) {
        if (!string_type && dtype->type_num == NPY_STRING) {
            Py_DECREF(dtype);
            return RETRY_WITH_STRING;
        }
        if (!string_type && dtype->type_num == NPY_UNICODE) {
            Py_DECREF(dtype);
            return RETRY_WITH_UNICODE;
        }
        *out_dtype = dtype;
        return 0;
    }
    /* Do type promotion with 'out_dtype' */
    else {
        PyArray_Descr *res_dtype = PyArray_PromoteTypes(dtype, *out_dtype);
        Py_DECREF(dtype);
        if (res_dtype == NULL) {
            return -1;
        }
        if (!string_type &&
                res_dtype->type_num == NPY_UNICODE &&
                (*out_dtype)->type_num != NPY_UNICODE) {
            Py_DECREF(res_dtype);
            return RETRY_WITH_UNICODE;
        }
        if (!string_type &&
                res_dtype->type_num == NPY_STRING &&
                (*out_dtype)->type_num != NPY_STRING) {
            Py_DECREF(res_dtype);
            return RETRY_WITH_STRING;
        }
        Py_DECREF(*out_dtype);
        *out_dtype = res_dtype;
        return 0;
    }

fail:
    Py_XDECREF(*out_dtype);
    *out_dtype = NULL;
    return -1;
}

#undef RETRY_WITH_STRING
#undef RETRY_WITH_UNICODE

/* new reference */
NPY_NO_EXPORT PyArray_Descr *
_array_typedescr_fromstr(char *c_str)
{
    PyArray_Descr *descr = NULL;
    PyObject *stringobj = PyString_FromString(c_str);

    if (stringobj == NULL) {
        return NULL;
    }
    if (PyArray_DescrConverter(stringobj, &descr) != NPY_SUCCEED) {
        Py_DECREF(stringobj);
        return NULL;
    }
    Py_DECREF(stringobj);
    return descr;
}


NPY_NO_EXPORT char *
index2ptr(PyArrayObject *mp, npy_intp i)
{
    npy_intp dim0;

    if (PyArray_NDIM(mp) == 0) {
        PyErr_SetString(PyExc_IndexError, "0-d arrays can't be indexed");
        return NULL;
    }
    dim0 = PyArray_DIMS(mp)[0];
    if (check_and_adjust_index(&i, dim0, 0) < 0)
        return NULL;
    if (i == 0) {
        return PyArray_DATA(mp);
    }
    return PyArray_BYTES(mp)+i*PyArray_STRIDES(mp)[0];
}
Ejemplo n.º 3
0
NPY_NO_EXPORT int
PyArray_DTypeFromObjectHelper(PyObject *obj, int maxdims,
                              PyArray_Descr **out_dtype, int string_type)
{
    int i, size;
    PyArray_Descr *dtype = NULL;
    PyObject *ip;
    Py_buffer buffer_view;
    /* types for sequence handling */
    PyObject ** objects;
    PyObject * seq;
    PyTypeObject * common_type;

    /* Check if it's an ndarray */
    if (PyArray_Check(obj)) {
        dtype = PyArray_DESCR((PyArrayObject *)obj);
        Py_INCREF(dtype);
        goto promote_types;
    }

    /* See if it's a python None */
    if (obj == Py_None) {
        dtype = PyArray_DescrFromType(NPY_OBJECT);
        if (dtype == NULL) {
            goto fail;
        }
        Py_INCREF(dtype);
        goto promote_types;
    }
    /* Check if it's a NumPy scalar */
    else if (PyArray_IsScalar(obj, Generic)) {
        if (!string_type) {
            dtype = PyArray_DescrFromScalar(obj);
            if (dtype == NULL) {
                goto fail;
            }
        }
        else {
            int itemsize;
            PyObject *temp;

            if (string_type == NPY_STRING) {
                if ((temp = PyObject_Str(obj)) == NULL) {
                    return -1;
                }
#if defined(NPY_PY3K)
    #if PY_VERSION_HEX >= 0x03030000
                itemsize = PyUnicode_GetLength(temp);
    #else
                itemsize = PyUnicode_GET_SIZE(temp);
    #endif
#else
                itemsize = PyString_GET_SIZE(temp);
#endif
            }
            else if (string_type == NPY_UNICODE) {
#if defined(NPY_PY3K)
                if ((temp = PyObject_Str(obj)) == NULL) {
#else
                if ((temp = PyObject_Unicode(obj)) == NULL) {
#endif
                    return -1;
                }
                itemsize = PyUnicode_GET_DATA_SIZE(temp);
#ifndef Py_UNICODE_WIDE
                itemsize <<= 1;
#endif
            }
            else {
                goto fail;
            }
            Py_DECREF(temp);
            if (*out_dtype != NULL &&
                    (*out_dtype)->type_num == string_type &&
                    (*out_dtype)->elsize >= itemsize) {
                return 0;
            }
            dtype = PyArray_DescrNewFromType(string_type);
            if (dtype == NULL) {
                goto fail;
            }
            dtype->elsize = itemsize;
        }
        goto promote_types;
    }

    /* Check if it's a Python scalar */
    dtype = _array_find_python_scalar_type(obj);
    if (dtype != NULL) {
        if (string_type) {
            int itemsize;
            PyObject *temp;

            if (string_type == NPY_STRING) {
                if ((temp = PyObject_Str(obj)) == NULL) {
                    return -1;
                }
#if defined(NPY_PY3K)
    #if PY_VERSION_HEX >= 0x03030000
                itemsize = PyUnicode_GetLength(temp);
    #else
                itemsize = PyUnicode_GET_SIZE(temp);
    #endif
#else
                itemsize = PyString_GET_SIZE(temp);
#endif
            }
            else if (string_type == NPY_UNICODE) {
#if defined(NPY_PY3K)
                if ((temp = PyObject_Str(obj)) == NULL) {
#else
                if ((temp = PyObject_Unicode(obj)) == NULL) {
#endif
                    return -1;
                }
                itemsize = PyUnicode_GET_DATA_SIZE(temp);
#ifndef Py_UNICODE_WIDE
                itemsize <<= 1;
#endif
            }
            else {
                goto fail;
            }
            Py_DECREF(temp);
            if (*out_dtype != NULL &&
                    (*out_dtype)->type_num == string_type &&
                    (*out_dtype)->elsize >= itemsize) {
                return 0;
            }
            dtype = PyArray_DescrNewFromType(string_type);
            if (dtype == NULL) {
                goto fail;
            }
            dtype->elsize = itemsize;
        }
        goto promote_types;
    }

    /* Check if it's an ASCII string */
    if (PyBytes_Check(obj)) {
        int itemsize = PyString_GET_SIZE(obj);

        /* If it's already a big enough string, don't bother type promoting */
        if (*out_dtype != NULL &&
                        (*out_dtype)->type_num == NPY_STRING &&
                        (*out_dtype)->elsize >= itemsize) {
            return 0;
        }
        dtype = PyArray_DescrNewFromType(NPY_STRING);
        if (dtype == NULL) {
            goto fail;
        }
        dtype->elsize = itemsize;
        goto promote_types;
    }

    /* Check if it's a Unicode string */
    if (PyUnicode_Check(obj)) {
        int itemsize = PyUnicode_GET_DATA_SIZE(obj);
#ifndef Py_UNICODE_WIDE
        itemsize <<= 1;
#endif

        /*
         * If it's already a big enough unicode object,
         * don't bother type promoting
         */
        if (*out_dtype != NULL &&
                        (*out_dtype)->type_num == NPY_UNICODE &&
                        (*out_dtype)->elsize >= itemsize) {
            return 0;
        }
        dtype = PyArray_DescrNewFromType(NPY_UNICODE);
        if (dtype == NULL) {
            goto fail;
        }
        dtype->elsize = itemsize;
        goto promote_types;
    }

    /* PEP 3118 buffer interface */
    if (PyObject_CheckBuffer(obj) == 1) {
        memset(&buffer_view, 0, sizeof(Py_buffer));
        if (PyObject_GetBuffer(obj, &buffer_view,
                               PyBUF_FORMAT|PyBUF_STRIDES) == 0 ||
            PyObject_GetBuffer(obj, &buffer_view, PyBUF_FORMAT) == 0) {

            PyErr_Clear();
            dtype = _descriptor_from_pep3118_format(buffer_view.format);
            PyBuffer_Release(&buffer_view);
            if (dtype) {
                goto promote_types;
            }
        }
        else if (PyObject_GetBuffer(obj, &buffer_view, PyBUF_STRIDES) == 0 ||
                 PyObject_GetBuffer(obj, &buffer_view, PyBUF_SIMPLE) == 0) {

            PyErr_Clear();
            dtype = PyArray_DescrNewFromType(NPY_VOID);
            dtype->elsize = buffer_view.itemsize;
            PyBuffer_Release(&buffer_view);
            goto promote_types;
        }
        else {
            PyErr_Clear();
        }
    }

    /* The array interface */
    ip = PyArray_LookupSpecial_OnInstance(obj, "__array_interface__");
    if (ip != NULL) {
        if (PyDict_Check(ip)) {
            PyObject *typestr;
#if defined(NPY_PY3K)
            PyObject *tmp = NULL;
#endif
            typestr = PyDict_GetItemString(ip, "typestr");
#if defined(NPY_PY3K)
            /* Allow unicode type strings */
            if (PyUnicode_Check(typestr)) {
                tmp = PyUnicode_AsASCIIString(typestr);
                typestr = tmp;
            }
#endif
            if (typestr && PyBytes_Check(typestr)) {
                dtype =_array_typedescr_fromstr(PyBytes_AS_STRING(typestr));
#if defined(NPY_PY3K)
                if (tmp == typestr) {
                    Py_DECREF(tmp);
                }
#endif
                Py_DECREF(ip);
                if (dtype == NULL) {
                    goto fail;
                }
                goto promote_types;
            }
        }
        Py_DECREF(ip);
    }

    /* The array struct interface */
    ip = PyArray_LookupSpecial_OnInstance(obj, "__array_struct__");
    if (ip != NULL) {
        PyArrayInterface *inter;
        char buf[40];

        if (NpyCapsule_Check(ip)) {
            inter = (PyArrayInterface *)NpyCapsule_AsVoidPtr(ip);
            if (inter->two == 2) {
                PyOS_snprintf(buf, sizeof(buf),
                        "|%c%d", inter->typekind, inter->itemsize);
                dtype = _array_typedescr_fromstr(buf);
                Py_DECREF(ip);
                if (dtype == NULL) {
                    goto fail;
                }
                goto promote_types;
            }
        }
        Py_DECREF(ip);
    }

    /* The old buffer interface */
#if !defined(NPY_PY3K)
    if (PyBuffer_Check(obj)) {
        dtype = PyArray_DescrNewFromType(NPY_VOID);
        if (dtype == NULL) {
            goto fail;
        }
        dtype->elsize = Py_TYPE(obj)->tp_as_sequence->sq_length(obj);
        PyErr_Clear();
        goto promote_types;
    }
#endif

    /* The __array__ attribute */
    ip = PyArray_LookupSpecial_OnInstance(obj, "__array__");
    if (ip != NULL) {
        Py_DECREF(ip);
        ip = PyObject_CallMethod(obj, "__array__", NULL);
        if(ip && PyArray_Check(ip)) {
            dtype = PyArray_DESCR((PyArrayObject *)ip);
            Py_INCREF(dtype);
            Py_DECREF(ip);
            goto promote_types;
        }
        Py_XDECREF(ip);
        if (PyErr_Occurred()) {
            goto fail;
        }
    }

    /*
     * If we reached the maximum recursion depth without hitting one
     * of the above cases, and obj isn't a sequence-like object, the output
     * dtype should be either OBJECT or a user-defined type.
     *
     * Note that some libraries define sequence-like classes but want them to
     * be treated as objects, and they expect numpy to treat it as an object if
     * __len__ is not defined.
     */
    if (maxdims == 0 || !PySequence_Check(obj) || PySequence_Size(obj) < 0) {
        // clear any PySequence_Size error, which corrupts further calls to it
        PyErr_Clear();

        if (*out_dtype == NULL || (*out_dtype)->type_num != NPY_OBJECT) {
            Py_XDECREF(*out_dtype);
            *out_dtype = PyArray_DescrFromType(NPY_OBJECT);
            if (*out_dtype == NULL) {
                return -1;
            }
        }
        return 0;
    }

    /* Recursive case, first check the sequence contains only one type */
    seq = PySequence_Fast(obj, "Could not convert object to sequence");
    if (seq == NULL) {
        goto fail;
    }
    size = PySequence_Fast_GET_SIZE(seq);
    objects = PySequence_Fast_ITEMS(seq);
    common_type = size > 0 ? Py_TYPE(objects[0]) : NULL;
    for (i = 1; i < size; ++i) {
        if (Py_TYPE(objects[i]) != common_type) {
            common_type = NULL;
            break;
        }
    }

    /* all types are the same and scalar, one recursive call is enough */
    if (common_type != NULL && !string_type &&
            (common_type == &PyFloat_Type ||
/* TODO: we could add longs if we add a range check */
#if !defined(NPY_PY3K)
             common_type == &PyInt_Type ||
#endif
             common_type == &PyBool_Type ||
             common_type == &PyComplex_Type)) {
        size = 1;
    }

    /* Recursive call for each sequence item */
    for (i = 0; i < size; ++i) {
        int res = PyArray_DTypeFromObjectHelper(objects[i], maxdims - 1,
                                                out_dtype, string_type);
        if (res < 0) {
            Py_DECREF(seq);
            goto fail;
        }
        else if (res > 0) {
            Py_DECREF(seq);
            return res;
        }
    }

    Py_DECREF(seq);

    return 0;


promote_types:
    /* Set 'out_dtype' if it's NULL */
    if (*out_dtype == NULL) {
        if (!string_type && dtype->type_num == NPY_STRING) {
            Py_DECREF(dtype);
            return RETRY_WITH_STRING;
        }
        if (!string_type && dtype->type_num == NPY_UNICODE) {
            Py_DECREF(dtype);
            return RETRY_WITH_UNICODE;
        }
        *out_dtype = dtype;
        return 0;
    }
    /* Do type promotion with 'out_dtype' */
    else {
        PyArray_Descr *res_dtype = PyArray_PromoteTypes(dtype, *out_dtype);
        Py_DECREF(dtype);
        if (res_dtype == NULL) {
            return -1;
        }
        if (!string_type &&
                res_dtype->type_num == NPY_UNICODE &&
                (*out_dtype)->type_num != NPY_UNICODE) {
            Py_DECREF(res_dtype);
            return RETRY_WITH_UNICODE;
        }
        if (!string_type &&
                res_dtype->type_num == NPY_STRING &&
                (*out_dtype)->type_num != NPY_STRING) {
            Py_DECREF(res_dtype);
            return RETRY_WITH_STRING;
        }
        Py_DECREF(*out_dtype);
        *out_dtype = res_dtype;
        return 0;
    }

fail:
    Py_XDECREF(*out_dtype);
    *out_dtype = NULL;
    return -1;
}

#undef RETRY_WITH_STRING
#undef RETRY_WITH_UNICODE

/* new reference */
NPY_NO_EXPORT PyArray_Descr *
_array_typedescr_fromstr(char *c_str)
{
    PyArray_Descr *descr = NULL;
    PyObject *stringobj = PyString_FromString(c_str);

    if (stringobj == NULL) {
        return NULL;
    }
    if (PyArray_DescrConverter(stringobj, &descr) != NPY_SUCCEED) {
        Py_DECREF(stringobj);
        return NULL;
    }
    Py_DECREF(stringobj);
    return descr;
}


NPY_NO_EXPORT char *
index2ptr(PyArrayObject *mp, npy_intp i)
{
    npy_intp dim0;

    if (PyArray_NDIM(mp) == 0) {
        PyErr_SetString(PyExc_IndexError, "0-d arrays can't be indexed");
        return NULL;
    }
    dim0 = PyArray_DIMS(mp)[0];
    if (check_and_adjust_index(&i, dim0, 0, NULL) < 0)
        return NULL;
    if (i == 0) {
        return PyArray_DATA(mp);
    }
    return PyArray_BYTES(mp)+i*PyArray_STRIDES(mp)[0];
}