dpnp4pybind11.hpp

//*****************************************************************************
// Copyright (c) 2026, Intel Corporation
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// - Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
// - Redistributions in binary form must reproduce the above copyright notice,
//   this list of conditions and the following disclaimer in the documentation
//   and/or other materials provided with the distribution.
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//   may be used to endorse or promote products derived from this software
//   without specific prior written permission.
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// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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//*****************************************************************************
 
#pragma once
 
#include "dpctl_capi.h"
 
#include <complex>
#include <cstddef> // for std::size_t for C++ linkage
#include <memory>
#include <stddef.h> // for size_t for C linkage
#include <stdexcept>
#include <utility>
#include <vector>
 
#include <pybind11/pybind11.h>
 
#include <sycl/sycl.hpp>
 
namespace py = pybind11;
 
namespace dpctl
{
namespace detail
{
// Lookup a type according to its size, and return a value corresponding to the
// NumPy typenum.
template <typename Concrete>
constexpr int platform_typeid_lookup()
{
    return -1;
}
 
template <typename Concrete, typename T, typename... Ts, typename... Ints>
constexpr int platform_typeid_lookup(int I, Ints... Is)
{
    return sizeof(Concrete) == sizeof(T)
               ? I
               : platform_typeid_lookup<Concrete, Ts...>(Is...);
}
 
class dpctl_capi
{
public:
    // dpctl type objects
    PyTypeObject *Py_SyclDeviceType_;
    PyTypeObject *PySyclDeviceType_;
    PyTypeObject *Py_SyclContextType_;
    PyTypeObject *PySyclContextType_;
    PyTypeObject *Py_SyclEventType_;
    PyTypeObject *PySyclEventType_;
    PyTypeObject *Py_SyclQueueType_;
    PyTypeObject *PySyclQueueType_;
    PyTypeObject *Py_MemoryType_;
    PyTypeObject *PyMemoryUSMDeviceType_;
    PyTypeObject *PyMemoryUSMSharedType_;
    PyTypeObject *PyMemoryUSMHostType_;
    PyTypeObject *PyUSMArrayType_;
    PyTypeObject *PySyclProgramType_;
    PyTypeObject *PySyclKernelType_;
 
    DPCTLSyclDeviceRef (*SyclDevice_GetDeviceRef_)(PySyclDeviceObject *);
    PySyclDeviceObject *(*SyclDevice_Make_)(DPCTLSyclDeviceRef);
 
    DPCTLSyclContextRef (*SyclContext_GetContextRef_)(PySyclContextObject *);
    PySyclContextObject *(*SyclContext_Make_)(DPCTLSyclContextRef);
 
    DPCTLSyclEventRef (*SyclEvent_GetEventRef_)(PySyclEventObject *);
    PySyclEventObject *(*SyclEvent_Make_)(DPCTLSyclEventRef);
 
    DPCTLSyclQueueRef (*SyclQueue_GetQueueRef_)(PySyclQueueObject *);
    PySyclQueueObject *(*SyclQueue_Make_)(DPCTLSyclQueueRef);
 
    // memory
    DPCTLSyclUSMRef (*Memory_GetUsmPointer_)(Py_MemoryObject *);
    void *(*Memory_GetOpaquePointer_)(Py_MemoryObject *);
    DPCTLSyclContextRef (*Memory_GetContextRef_)(Py_MemoryObject *);
    DPCTLSyclQueueRef (*Memory_GetQueueRef_)(Py_MemoryObject *);
    size_t (*Memory_GetNumBytes_)(Py_MemoryObject *);
    PyObject *(*Memory_Make_)(DPCTLSyclUSMRef,
                              size_t,
                              DPCTLSyclQueueRef,
                              PyObject *);
 
    // program
    DPCTLSyclKernelRef (*SyclKernel_GetKernelRef_)(PySyclKernelObject *);
    PySyclKernelObject *(*SyclKernel_Make_)(DPCTLSyclKernelRef, const char *);
 
    DPCTLSyclKernelBundleRef (*SyclProgram_GetKernelBundleRef_)(
        PySyclProgramObject *);
    PySyclProgramObject *(*SyclProgram_Make_)(DPCTLSyclKernelBundleRef);
 
    // tensor
    char *(*UsmNDArray_GetData_)(PyUSMArrayObject *);
    int (*UsmNDArray_GetNDim_)(PyUSMArrayObject *);
    py::ssize_t *(*UsmNDArray_GetShape_)(PyUSMArrayObject *);
    py::ssize_t *(*UsmNDArray_GetStrides_)(PyUSMArrayObject *);
    int (*UsmNDArray_GetTypenum_)(PyUSMArrayObject *);
    int (*UsmNDArray_GetElementSize_)(PyUSMArrayObject *);
    int (*UsmNDArray_GetFlags_)(PyUSMArrayObject *);
    DPCTLSyclQueueRef (*UsmNDArray_GetQueueRef_)(PyUSMArrayObject *);
    py::ssize_t (*UsmNDArray_GetOffset_)(PyUSMArrayObject *);
    PyObject *(*UsmNDArray_GetUSMData_)(PyUSMArrayObject *);
    void (*UsmNDArray_SetWritableFlag_)(PyUSMArrayObject *, int);
    PyObject *(*UsmNDArray_MakeSimpleFromMemory_)(int,
                                                  const py::ssize_t *,
                                                  int,
                                                  Py_MemoryObject *,
                                                  py::ssize_t,
                                                  char);
    PyObject *(*UsmNDArray_MakeSimpleFromPtr_)(size_t,
                                               int,
                                               DPCTLSyclUSMRef,
                                               DPCTLSyclQueueRef,
                                               PyObject *);
    PyObject *(*UsmNDArray_MakeFromPtr_)(int,
                                         const py::ssize_t *,
                                         int,
                                         const py::ssize_t *,
                                         DPCTLSyclUSMRef,
                                         DPCTLSyclQueueRef,
                                         py::ssize_t,
                                         PyObject *);
 
    int USM_ARRAY_C_CONTIGUOUS_;
    int USM_ARRAY_F_CONTIGUOUS_;
    int USM_ARRAY_WRITABLE_;
    int UAR_BOOL_, UAR_BYTE_, UAR_UBYTE_, UAR_SHORT_, UAR_USHORT_, UAR_INT_,
        UAR_UINT_, UAR_LONG_, UAR_ULONG_, UAR_LONGLONG_, UAR_ULONGLONG_,
        UAR_FLOAT_, UAR_DOUBLE_, UAR_CFLOAT_, UAR_CDOUBLE_, UAR_TYPE_SENTINEL_,
        UAR_HALF_;
    int UAR_INT8_, UAR_UINT8_, UAR_INT16_, UAR_UINT16_, UAR_INT32_, UAR_UINT32_,
        UAR_INT64_, UAR_UINT64_;
 
    bool PySyclDevice_Check_(PyObject *obj) const
    {
        return PyObject_TypeCheck(obj, PySyclDeviceType_) != 0;
    }
    bool PySyclContext_Check_(PyObject *obj) const
    {
        return PyObject_TypeCheck(obj, PySyclContextType_) != 0;
    }
    bool PySyclEvent_Check_(PyObject *obj) const
    {
        return PyObject_TypeCheck(obj, PySyclEventType_) != 0;
    }
    bool PySyclQueue_Check_(PyObject *obj) const
    {
        return PyObject_TypeCheck(obj, PySyclQueueType_) != 0;
    }
    bool PySyclKernel_Check_(PyObject *obj) const
    {
        return PyObject_TypeCheck(obj, PySyclKernelType_) != 0;
    }
    bool PySyclProgram_Check_(PyObject *obj) const
    {
        return PyObject_TypeCheck(obj, PySyclProgramType_) != 0;
    }
 
    ~dpctl_capi()
    {
        as_usm_memory_.reset();
        default_usm_ndarray_.reset();
        default_usm_memory_.reset();
        default_sycl_queue_.reset();
    };
 
    static auto &get()
    {
        static dpctl_capi api{};
        return api;
    }
 
    py::object default_sycl_queue_pyobj()
    {
        return *default_sycl_queue_;
    }
    py::object default_usm_memory_pyobj()
    {
        return *default_usm_memory_;
    }
    py::object default_usm_ndarray_pyobj()
    {
        return *default_usm_ndarray_;
    }
    py::object as_usm_memory_pyobj()
    {
        return *as_usm_memory_;
    }
 
private:
    struct Deleter
    {
        void operator()(py::object *p) const
        {
            const bool initialized = Py_IsInitialized();
#if PY_VERSION_HEX < 0x30d0000
            const bool finalizing = _Py_IsFinalizing();
#else
            const bool finalizing = Py_IsFinalizing();
#endif
            const bool guard = initialized && !finalizing;
 
            if (guard) {
                delete p;
            }
        }
    };
 
    std::shared_ptr<py::object> default_sycl_queue_;
    std::shared_ptr<py::object> default_usm_memory_;
    std::shared_ptr<py::object> default_usm_ndarray_;
    std::shared_ptr<py::object> as_usm_memory_;
 
    dpctl_capi()
        : Py_SyclDeviceType_(nullptr), PySyclDeviceType_(nullptr),
          Py_SyclContextType_(nullptr), PySyclContextType_(nullptr),
          Py_SyclEventType_(nullptr), PySyclEventType_(nullptr),
          Py_SyclQueueType_(nullptr), PySyclQueueType_(nullptr),
          Py_MemoryType_(nullptr), PyMemoryUSMDeviceType_(nullptr),
          PyMemoryUSMSharedType_(nullptr), PyMemoryUSMHostType_(nullptr),
          PyUSMArrayType_(nullptr), PySyclProgramType_(nullptr),
          PySyclKernelType_(nullptr), SyclDevice_GetDeviceRef_(nullptr),
          SyclDevice_Make_(nullptr), SyclContext_GetContextRef_(nullptr),
          SyclContext_Make_(nullptr), SyclEvent_GetEventRef_(nullptr),
          SyclEvent_Make_(nullptr), SyclQueue_GetQueueRef_(nullptr),
          SyclQueue_Make_(nullptr), Memory_GetUsmPointer_(nullptr),
          Memory_GetOpaquePointer_(nullptr), Memory_GetContextRef_(nullptr),
          Memory_GetQueueRef_(nullptr), Memory_GetNumBytes_(nullptr),
          Memory_Make_(nullptr), SyclKernel_GetKernelRef_(nullptr),
          SyclKernel_Make_(nullptr), SyclProgram_GetKernelBundleRef_(nullptr),
          SyclProgram_Make_(nullptr), UsmNDArray_GetData_(nullptr),
          UsmNDArray_GetNDim_(nullptr), UsmNDArray_GetShape_(nullptr),
          UsmNDArray_GetStrides_(nullptr), UsmNDArray_GetTypenum_(nullptr),
          UsmNDArray_GetElementSize_(nullptr), UsmNDArray_GetFlags_(nullptr),
          UsmNDArray_GetQueueRef_(nullptr), UsmNDArray_GetOffset_(nullptr),
          UsmNDArray_GetUSMData_(nullptr), UsmNDArray_SetWritableFlag_(nullptr),
          UsmNDArray_MakeSimpleFromMemory_(nullptr),
          UsmNDArray_MakeSimpleFromPtr_(nullptr),
          UsmNDArray_MakeFromPtr_(nullptr), USM_ARRAY_C_CONTIGUOUS_(0),
          USM_ARRAY_F_CONTIGUOUS_(0), USM_ARRAY_WRITABLE_(0), UAR_BOOL_(-1),
          UAR_BYTE_(-1), UAR_UBYTE_(-1), UAR_SHORT_(-1), UAR_USHORT_(-1),
          UAR_INT_(-1), UAR_UINT_(-1), UAR_LONG_(-1), UAR_ULONG_(-1),
          UAR_LONGLONG_(-1), UAR_ULONGLONG_(-1), UAR_FLOAT_(-1),
          UAR_DOUBLE_(-1), UAR_CFLOAT_(-1), UAR_CDOUBLE_(-1),
          UAR_TYPE_SENTINEL_(-1), UAR_HALF_(-1), UAR_INT8_(-1), UAR_UINT8_(-1),
          UAR_INT16_(-1), UAR_UINT16_(-1), UAR_INT32_(-1), UAR_UINT32_(-1),
          UAR_INT64_(-1), UAR_UINT64_(-1), default_sycl_queue_{},
          default_usm_memory_{}, default_usm_ndarray_{}, as_usm_memory_{}
 
    {
        // Import Cython-generated C-API for dpctl
        // This imports python modules and initializes
        // static variables such as function pointers for C-API,
        // e.g. SyclDevice_GetDeviceRef, etc.
        // pointers to Python types, i.e. PySyclDeviceType, etc.
        // and exported constants, i.e. USM_ARRAY_C_CONTIGUOUS, etc.
        import_dpctl();
 
        // Python type objects for classes implemented by dpctl
        this->Py_SyclDeviceType_ = &Py_SyclDeviceType;
        this->PySyclDeviceType_ = &PySyclDeviceType;
        this->Py_SyclContextType_ = &Py_SyclContextType;
        this->PySyclContextType_ = &PySyclContextType;
        this->Py_SyclEventType_ = &Py_SyclEventType;
        this->PySyclEventType_ = &PySyclEventType;
        this->Py_SyclQueueType_ = &Py_SyclQueueType;
        this->PySyclQueueType_ = &PySyclQueueType;
        this->Py_MemoryType_ = &Py_MemoryType;
        this->PyMemoryUSMDeviceType_ = &PyMemoryUSMDeviceType;
        this->PyMemoryUSMSharedType_ = &PyMemoryUSMSharedType;
        this->PyMemoryUSMHostType_ = &PyMemoryUSMHostType;
        this->PyUSMArrayType_ = &PyUSMArrayType;
        this->PySyclProgramType_ = &PySyclProgramType;
        this->PySyclKernelType_ = &PySyclKernelType;
 
        // SyclDevice API
        this->SyclDevice_GetDeviceRef_ = SyclDevice_GetDeviceRef;
        this->SyclDevice_Make_ = SyclDevice_Make;
 
        // SyclContext API
        this->SyclContext_GetContextRef_ = SyclContext_GetContextRef;
        this->SyclContext_Make_ = SyclContext_Make;
 
        // SyclEvent API
        this->SyclEvent_GetEventRef_ = SyclEvent_GetEventRef;
        this->SyclEvent_Make_ = SyclEvent_Make;
 
        // SyclQueue API
        this->SyclQueue_GetQueueRef_ = SyclQueue_GetQueueRef;
        this->SyclQueue_Make_ = SyclQueue_Make;
 
        // dpctl.memory API
        this->Memory_GetUsmPointer_ = Memory_GetUsmPointer;
        this->Memory_GetOpaquePointer_ = Memory_GetOpaquePointer;
        this->Memory_GetContextRef_ = Memory_GetContextRef;
        this->Memory_GetQueueRef_ = Memory_GetQueueRef;
        this->Memory_GetNumBytes_ = Memory_GetNumBytes;
        this->Memory_Make_ = Memory_Make;
 
        // dpctl.program API
        this->SyclKernel_GetKernelRef_ = SyclKernel_GetKernelRef;
        this->SyclKernel_Make_ = SyclKernel_Make;
        this->SyclProgram_GetKernelBundleRef_ = SyclProgram_GetKernelBundleRef;
        this->SyclProgram_Make_ = SyclProgram_Make;
 
        // dpctl.tensor.usm_ndarray API
        this->UsmNDArray_GetData_ = UsmNDArray_GetData;
        this->UsmNDArray_GetNDim_ = UsmNDArray_GetNDim;
        this->UsmNDArray_GetShape_ = UsmNDArray_GetShape;
        this->UsmNDArray_GetStrides_ = UsmNDArray_GetStrides;
        this->UsmNDArray_GetTypenum_ = UsmNDArray_GetTypenum;
        this->UsmNDArray_GetElementSize_ = UsmNDArray_GetElementSize;
        this->UsmNDArray_GetFlags_ = UsmNDArray_GetFlags;
        this->UsmNDArray_GetQueueRef_ = UsmNDArray_GetQueueRef;
        this->UsmNDArray_GetOffset_ = UsmNDArray_GetOffset;
        this->UsmNDArray_GetUSMData_ = UsmNDArray_GetUSMData;
        this->UsmNDArray_SetWritableFlag_ = UsmNDArray_SetWritableFlag;
        this->UsmNDArray_MakeSimpleFromMemory_ =
            UsmNDArray_MakeSimpleFromMemory;
        this->UsmNDArray_MakeSimpleFromPtr_ = UsmNDArray_MakeSimpleFromPtr;
        this->UsmNDArray_MakeFromPtr_ = UsmNDArray_MakeFromPtr;
 
        // constants
        this->USM_ARRAY_C_CONTIGUOUS_ = USM_ARRAY_C_CONTIGUOUS;
        this->USM_ARRAY_F_CONTIGUOUS_ = USM_ARRAY_F_CONTIGUOUS;
        this->USM_ARRAY_WRITABLE_ = USM_ARRAY_WRITABLE;
        this->UAR_BOOL_ = UAR_BOOL;
        this->UAR_BYTE_ = UAR_BYTE;
        this->UAR_UBYTE_ = UAR_UBYTE;
        this->UAR_SHORT_ = UAR_SHORT;
        this->UAR_USHORT_ = UAR_USHORT;
        this->UAR_INT_ = UAR_INT;
        this->UAR_UINT_ = UAR_UINT;
        this->UAR_LONG_ = UAR_LONG;
        this->UAR_ULONG_ = UAR_ULONG;
        this->UAR_LONGLONG_ = UAR_LONGLONG;
        this->UAR_ULONGLONG_ = UAR_ULONGLONG;
        this->UAR_FLOAT_ = UAR_FLOAT;
        this->UAR_DOUBLE_ = UAR_DOUBLE;
        this->UAR_CFLOAT_ = UAR_CFLOAT;
        this->UAR_CDOUBLE_ = UAR_CDOUBLE;
        this->UAR_TYPE_SENTINEL_ = UAR_TYPE_SENTINEL;
        this->UAR_HALF_ = UAR_HALF;
 
        // deduced disjoint types
        this->UAR_INT8_ = UAR_BYTE;
        this->UAR_UINT8_ = UAR_UBYTE;
        this->UAR_INT16_ = UAR_SHORT;
        this->UAR_UINT16_ = UAR_USHORT;
        this->UAR_INT32_ =
            platform_typeid_lookup<std::int32_t, long, int, short>(
                UAR_LONG, UAR_INT, UAR_SHORT);
        this->UAR_UINT32_ =
            platform_typeid_lookup<std::uint32_t, unsigned long, unsigned int,
                                   unsigned short>(UAR_ULONG, UAR_UINT,
                                                   UAR_USHORT);
        this->UAR_INT64_ =
            platform_typeid_lookup<std::int64_t, long, long long, int>(
                UAR_LONG, UAR_LONGLONG, UAR_INT);
        this->UAR_UINT64_ =
            platform_typeid_lookup<std::uint64_t, unsigned long,
                                   unsigned long long, unsigned int>(
                UAR_ULONG, UAR_ULONGLONG, UAR_UINT);
 
        // create shared pointers to python objects used in type-casters
        // for dpctl::memory::usm_memory and dpctl::tensor::usm_ndarray
        sycl::queue q_{};
        PySyclQueueObject *py_q_tmp =
            SyclQueue_Make(reinterpret_cast<DPCTLSyclQueueRef>(&q_));
        const py::object &py_sycl_queue = py::reinterpret_steal<py::object>(
            reinterpret_cast<PyObject *>(py_q_tmp));
 
        default_sycl_queue_ = std::shared_ptr<py::object>(
            new py::object(py_sycl_queue), Deleter{});
 
        py::module_ mod_memory = py::module_::import("dpctl.memory");
        const py::object &py_as_usm_memory = mod_memory.attr("as_usm_memory");
        as_usm_memory_ = std::shared_ptr<py::object>(
            new py::object{py_as_usm_memory}, Deleter{});
 
        auto mem_kl = mod_memory.attr("MemoryUSMHost");
        const py::object &py_default_usm_memory =
            mem_kl(1, py::arg("queue") = py_sycl_queue);
        default_usm_memory_ = std::shared_ptr<py::object>(
            new py::object{py_default_usm_memory}, Deleter{});
 
        py::module_ mod_usmarray =
            py::module_::import("dpctl.tensor._usmarray");
        auto tensor_kl = mod_usmarray.attr("usm_ndarray");
 
        const py::object &py_default_usm_ndarray =
            tensor_kl(py::tuple(), py::arg("dtype") = py::str("u1"),
                      py::arg("buffer") = py_default_usm_memory);
 
        default_usm_ndarray_ = std::shared_ptr<py::object>(
            new py::object{py_default_usm_ndarray}, Deleter{});
    }
 
    dpctl_capi(dpctl_capi const &) = default;
    dpctl_capi &operator=(dpctl_capi const &) = default;
    dpctl_capi &operator=(dpctl_capi &&) = default;
 
}; // struct dpctl_capi
} // namespace detail
} // namespace dpctl
 
namespace pybind11::detail
{
#define DPCTL_TYPE_CASTER(type, py_name)                                       \
protected:                                                                     \
    std::unique_ptr<type> value;                                               \
                                                                               \
public:                                                                        \
    static constexpr auto name = py_name;                                      \
    template <                                                                 \
        typename T_,                                                           \
        ::pybind11::detail::enable_if_t<                                       \
            std::is_same<type, ::pybind11::detail::remove_cv_t<T_>>::value,    \
            int> = 0>                                                          \
    static ::pybind11::handle cast(T_ *src,                                    \
                                   ::pybind11::return_value_policy policy,     \
                                   ::pybind11::handle parent)                  \
    {                                                                          \
        if (!src)                                                              \
            return ::pybind11::none().release();                               \
        if (policy == ::pybind11::return_value_policy::take_ownership) {       \
            auto h = cast(std::move(*src), policy, parent);                    \
            delete src;                                                        \
            return h;                                                          \
        }                                                                      \
        return cast(*src, policy, parent);                                     \
    }                                                                          \
    operator type *()                                                          \
    {                                                                          \
        return value.get();                                                    \
    } /* NOLINT(bugprone-macro-parentheses) */                                 \
    operator type &()                                                          \
    {                                                                          \
        return *value;                                                         \
    } /* NOLINT(bugprone-macro-parentheses) */                                 \
    operator type &&() &&                                                      \
    {                                                                          \
        return std::move(*value);                                              \
    } /* NOLINT(bugprone-macro-parentheses) */                                 \
    template <typename T_>                                                     \
    using cast_op_type = ::pybind11::detail::movable_cast_op_type<T_>
 
/* This type caster associates ``sycl::queue`` C++ class with
 * :class:`dpctl.SyclQueue` for the purposes of generation of
 * Python bindings by pybind11.
 */
template <>
struct type_caster<sycl::queue>
{
public:
    bool load(handle src, bool)
    {
        PyObject *source = src.ptr();
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        if (api.PySyclQueue_Check_(source)) {
            DPCTLSyclQueueRef QRef = api.SyclQueue_GetQueueRef_(
                reinterpret_cast<PySyclQueueObject *>(source));
            value = std::make_unique<sycl::queue>(
                *(reinterpret_cast<sycl::queue *>(QRef)));
            return true;
        }
        else {
            throw py::type_error(
                "Input is of unexpected type, expected dpctl.SyclQueue");
        }
    }
 
    static handle cast(sycl::queue src, return_value_policy, handle)
    {
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        auto tmp =
            api.SyclQueue_Make_(reinterpret_cast<DPCTLSyclQueueRef>(&src));
        return handle(reinterpret_cast<PyObject *>(tmp));
    }
 
    DPCTL_TYPE_CASTER(sycl::queue, _("dpctl.SyclQueue"));
};
 
/* This type caster associates ``sycl::device`` C++ class with
 * :class:`dpctl.SyclDevice` for the purposes of generation of
 * Python bindings by pybind11.
 */
template <>
struct type_caster<sycl::device>
{
public:
    bool load(handle src, bool)
    {
        PyObject *source = src.ptr();
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        if (api.PySyclDevice_Check_(source)) {
            DPCTLSyclDeviceRef DRef = api.SyclDevice_GetDeviceRef_(
                reinterpret_cast<PySyclDeviceObject *>(source));
            value = std::make_unique<sycl::device>(
                *(reinterpret_cast<sycl::device *>(DRef)));
            return true;
        }
        else {
            throw py::type_error(
                "Input is of unexpected type, expected dpctl.SyclDevice");
        }
    }
 
    static handle cast(sycl::device src, return_value_policy, handle)
    {
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        auto tmp =
            api.SyclDevice_Make_(reinterpret_cast<DPCTLSyclDeviceRef>(&src));
        return handle(reinterpret_cast<PyObject *>(tmp));
    }
 
    DPCTL_TYPE_CASTER(sycl::device, _("dpctl.SyclDevice"));
};
 
/* This type caster associates ``sycl::context`` C++ class with
 * :class:`dpctl.SyclContext` for the purposes of generation of
 * Python bindings by pybind11.
 */
template <>
struct type_caster<sycl::context>
{
public:
    bool load(handle src, bool)
    {
        PyObject *source = src.ptr();
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        if (api.PySyclContext_Check_(source)) {
            DPCTLSyclContextRef CRef = api.SyclContext_GetContextRef_(
                reinterpret_cast<PySyclContextObject *>(source));
            value = std::make_unique<sycl::context>(
                *(reinterpret_cast<sycl::context *>(CRef)));
            return true;
        }
        else {
            throw py::type_error(
                "Input is of unexpected type, expected dpctl.SyclContext");
        }
    }
 
    static handle cast(sycl::context src, return_value_policy, handle)
    {
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        auto tmp =
            api.SyclContext_Make_(reinterpret_cast<DPCTLSyclContextRef>(&src));
        return handle(reinterpret_cast<PyObject *>(tmp));
    }
 
    DPCTL_TYPE_CASTER(sycl::context, _("dpctl.SyclContext"));
};
 
/* This type caster associates ``sycl::event`` C++ class with
 * :class:`dpctl.SyclEvent` for the purposes of generation of
 * Python bindings by pybind11.
 */
template <>
struct type_caster<sycl::event>
{
public:
    bool load(handle src, bool)
    {
        PyObject *source = src.ptr();
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        if (api.PySyclEvent_Check_(source)) {
            DPCTLSyclEventRef ERef = api.SyclEvent_GetEventRef_(
                reinterpret_cast<PySyclEventObject *>(source));
            value = std::make_unique<sycl::event>(
                *(reinterpret_cast<sycl::event *>(ERef)));
            return true;
        }
        else {
            throw py::type_error(
                "Input is of unexpected type, expected dpctl.SyclEvent");
        }
    }
 
    static handle cast(sycl::event src, return_value_policy, handle)
    {
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        auto tmp =
            api.SyclEvent_Make_(reinterpret_cast<DPCTLSyclEventRef>(&src));
        return handle(reinterpret_cast<PyObject *>(tmp));
    }
 
    DPCTL_TYPE_CASTER(sycl::event, _("dpctl.SyclEvent"));
};
 
/* This type caster associates ``sycl::kernel`` C++ class with
 * :class:`dpctl.program.SyclKernel` for the purposes of generation of
 * Python bindings by pybind11.
 */
template <>
struct type_caster<sycl::kernel>
{
public:
    bool load(handle src, bool)
    {
        PyObject *source = src.ptr();
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        if (api.PySyclKernel_Check_(source)) {
            DPCTLSyclKernelRef KRef = api.SyclKernel_GetKernelRef_(
                reinterpret_cast<PySyclKernelObject *>(source));
            value = std::make_unique<sycl::kernel>(
                *(reinterpret_cast<sycl::kernel *>(KRef)));
            return true;
        }
        else {
            throw py::type_error("Input is of unexpected type, expected "
                                 "dpctl.program.SyclKernel");
        }
    }
 
    static handle cast(sycl::kernel src, return_value_policy, handle)
    {
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        auto tmp =
            api.SyclKernel_Make_(reinterpret_cast<DPCTLSyclKernelRef>(&src),
                                 "dpctl4pybind11_kernel");
        return handle(reinterpret_cast<PyObject *>(tmp));
    }
 
    DPCTL_TYPE_CASTER(sycl::kernel, _("dpctl.program.SyclKernel"));
};
 
/* This type caster associates
 * ``sycl::kernel_bundle<sycl::bundle_state::executable>`` C++ class with
 * :class:`dpctl.program.SyclProgram` for the purposes of generation of
 * Python bindings by pybind11.
 */
template <>
struct type_caster<sycl::kernel_bundle<sycl::bundle_state::executable>>
{
public:
    bool load(handle src, bool)
    {
        PyObject *source = src.ptr();
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        if (api.PySyclProgram_Check_(source)) {
            DPCTLSyclKernelBundleRef KBRef =
                api.SyclProgram_GetKernelBundleRef_(
                    reinterpret_cast<PySyclProgramObject *>(source));
            value = std::make_unique<
                sycl::kernel_bundle<sycl::bundle_state::executable>>(
                *(reinterpret_cast<
                    sycl::kernel_bundle<sycl::bundle_state::executable> *>(
                    KBRef)));
            return true;
        }
        else {
            throw py::type_error("Input is of unexpected type, expected "
                                 "dpctl.program.SyclProgram");
        }
    }
 
    static handle cast(sycl::kernel_bundle<sycl::bundle_state::executable> src,
                       return_value_policy,
                       handle)
    {
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        auto tmp = api.SyclProgram_Make_(
            reinterpret_cast<DPCTLSyclKernelBundleRef>(&src));
        return handle(reinterpret_cast<PyObject *>(tmp));
    }
 
    DPCTL_TYPE_CASTER(sycl::kernel_bundle<sycl::bundle_state::executable>,
                      _("dpctl.program.SyclProgram"));
};
 
/* This type caster associates
 * ``sycl::half`` C++ class with Python :class:`float` for the purposes
 * of generation of Python bindings by pybind11.
 */
template <>
struct type_caster<sycl::half>
{
public:
    bool load(handle src, bool convert)
    {
        double py_value;
 
        if (!src) {
            return false;
        }
 
        PyObject *source = src.ptr();
 
        if (convert || PyFloat_Check(source)) {
            py_value = PyFloat_AsDouble(source);
        }
        else {
            return false;
        }
 
        bool py_err = (py_value == double(-1)) && PyErr_Occurred();
 
        if (py_err) {
            PyErr_Clear();
            if (convert && (PyNumber_Check(source) != 0)) {
                auto tmp = reinterpret_steal<object>(PyNumber_Float(source));
                return load(tmp, false);
            }
            return false;
        }
        value = static_cast<sycl::half>(py_value);
        return true;
    }
 
    static handle cast(sycl::half src, return_value_policy, handle)
    {
        return PyFloat_FromDouble(static_cast<double>(src));
    }
 
    PYBIND11_TYPE_CASTER(sycl::half, _("float"));
};
} // namespace pybind11::detail
 
namespace dpctl
{
namespace memory
{
// since PYBIND11_OBJECT_CVT uses error_already_set without namespace,
// this allows to avoid compilation error
using pybind11::error_already_set;
 
class usm_memory : public py::object
{
public:
    PYBIND11_OBJECT_CVT(
        usm_memory,
        py::object,
        [](PyObject *o) -> bool {
            return PyObject_TypeCheck(
                       o, ::dpctl::detail::dpctl_capi::get().Py_MemoryType_) !=
                   0;
        },
        [](PyObject *o) -> PyObject * { return as_usm_memory(o); })
 
    usm_memory()
        : py::object(
              ::dpctl::detail::dpctl_capi::get().default_usm_memory_pyobj(),
              borrowed_t{})
    {
        if (!m_ptr)
            throw py::error_already_set();
    }
 
    usm_memory(void *usm_ptr,
               std::size_t nbytes,
               const sycl::queue &q,
               std::shared_ptr<void> shptr)
    {
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        DPCTLSyclUSMRef usm_ref = reinterpret_cast<DPCTLSyclUSMRef>(usm_ptr);
        auto q_uptr = std::make_unique<sycl::queue>(q);
        DPCTLSyclQueueRef QRef =
            reinterpret_cast<DPCTLSyclQueueRef>(q_uptr.get());
 
        auto vacuous_destructor = []() {};
        py::capsule mock_owner(vacuous_destructor);
 
        // create memory object owned by mock_owner, it is a new reference
        PyObject *_memory =
            api.Memory_Make_(usm_ref, nbytes, QRef, mock_owner.ptr());
        auto ref_count_decrementer = [](PyObject *o) noexcept { Py_DECREF(o); };
 
        using py_uptrT =
            std::unique_ptr<PyObject, decltype(ref_count_decrementer)>;
 
        if (!_memory) {
            throw py::error_already_set();
        }
 
        auto memory_uptr = py_uptrT(_memory, ref_count_decrementer);
        std::shared_ptr<void> *opaque_ptr = new std::shared_ptr<void>(shptr);
 
        Py_MemoryObject *memobj = reinterpret_cast<Py_MemoryObject *>(_memory);
        // replace mock_owner capsule as the owner
        memobj->refobj = Py_None;
        // set opaque ptr field, usm_memory now knowns that USM is managed
        // by smart pointer
        memobj->_opaque_ptr = reinterpret_cast<void *>(opaque_ptr);
 
        // _memory will delete created copies of sycl::queue, and
        // std::shared_ptr and the deleter of the shared_ptr<void> is
        // supposed to free the USM allocation
        m_ptr = _memory;
        q_uptr.release();
        memory_uptr.release();
    }
 
    sycl::queue get_queue() const
    {
        Py_MemoryObject *mem_obj = reinterpret_cast<Py_MemoryObject *>(m_ptr);
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        DPCTLSyclQueueRef QRef = api.Memory_GetQueueRef_(mem_obj);
        sycl::queue *obj_q = reinterpret_cast<sycl::queue *>(QRef);
        return *obj_q;
    }
 
    char *get_pointer() const
    {
        Py_MemoryObject *mem_obj = reinterpret_cast<Py_MemoryObject *>(m_ptr);
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        DPCTLSyclUSMRef MRef = api.Memory_GetUsmPointer_(mem_obj);
        return reinterpret_cast<char *>(MRef);
    }
 
    std::size_t get_nbytes() const
    {
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        Py_MemoryObject *mem_obj = reinterpret_cast<Py_MemoryObject *>(m_ptr);
        return api.Memory_GetNumBytes_(mem_obj);
    }
 
    bool is_managed_by_smart_ptr() const
    {
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        Py_MemoryObject *mem_obj = reinterpret_cast<Py_MemoryObject *>(m_ptr);
        const void *opaque_ptr = api.Memory_GetOpaquePointer_(mem_obj);
 
        return bool(opaque_ptr);
    }
 
    const std::shared_ptr<void> &get_smart_ptr_owner() const
    {
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        Py_MemoryObject *mem_obj = reinterpret_cast<Py_MemoryObject *>(m_ptr);
        void *opaque_ptr = api.Memory_GetOpaquePointer_(mem_obj);
 
        if (opaque_ptr) {
            auto shptr_ptr =
                reinterpret_cast<std::shared_ptr<void> *>(opaque_ptr);
            return *shptr_ptr;
        }
        else {
            throw std::runtime_error(
                "Memory object does not have smart pointer "
                "managing lifetime of USM allocation");
        }
    }
 
protected:
    static PyObject *as_usm_memory(PyObject *o)
    {
        if (o == nullptr) {
            PyErr_SetString(PyExc_ValueError,
                            "cannot create a usm_memory from a nullptr");
            return nullptr;
        }
 
        auto converter =
            ::dpctl::detail::dpctl_capi::get().as_usm_memory_pyobj();
 
        py::object res;
        try {
            res = converter(py::handle(o));
        } catch (const py::error_already_set &e) {
            return nullptr;
        }
        return res.ptr();
    }
};
} // end namespace memory
 
namespace tensor
{
inline std::vector<py::ssize_t>
    c_contiguous_strides(int nd,
                         const py::ssize_t *shape,
                         py::ssize_t element_size = 1)
{
    if (nd > 0) {
        std::vector<py::ssize_t> c_strides(nd, element_size);
        for (int ic = nd - 1; ic > 0;) {
            py::ssize_t next_v = c_strides[ic] * shape[ic];
            c_strides[--ic] = next_v;
        }
        return c_strides;
    }
    else {
        return std::vector<py::ssize_t>();
    }
}
 
inline std::vector<py::ssize_t>
    f_contiguous_strides(int nd,
                         const py::ssize_t *shape,
                         py::ssize_t element_size = 1)
{
    if (nd > 0) {
        std::vector<py::ssize_t> f_strides(nd, element_size);
        for (int i = 0; i < nd - 1;) {
            py::ssize_t next_v = f_strides[i] * shape[i];
            f_strides[++i] = next_v;
        }
        return f_strides;
    }
    else {
        return std::vector<py::ssize_t>();
    }
}
 
inline std::vector<py::ssize_t>
    c_contiguous_strides(const std::vector<py::ssize_t> &shape,
                         py::ssize_t element_size = 1)
{
    return c_contiguous_strides(shape.size(), shape.data(), element_size);
}
 
inline std::vector<py::ssize_t>
    f_contiguous_strides(const std::vector<py::ssize_t> &shape,
                         py::ssize_t element_size = 1)
{
    return f_contiguous_strides(shape.size(), shape.data(), element_size);
}
 
class usm_ndarray : public py::object
{
public:
    PYBIND11_OBJECT(usm_ndarray, py::object, [](PyObject *o) -> bool {
        return PyObject_TypeCheck(
                   o, ::dpctl::detail::dpctl_capi::get().PyUSMArrayType_) != 0;
    })
 
    usm_ndarray()
        : py::object(
              ::dpctl::detail::dpctl_capi::get().default_usm_ndarray_pyobj(),
              borrowed_t{})
    {
        if (!m_ptr)
            throw py::error_already_set();
    }
 
    char *get_data() const
    {
        PyUSMArrayObject *raw_ar = usm_array_ptr();
 
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        return api.UsmNDArray_GetData_(raw_ar);
    }
 
    template <typename T>
    T *get_data() const
    {
        return reinterpret_cast<T *>(get_data());
    }
 
    int get_ndim() const
    {
        PyUSMArrayObject *raw_ar = usm_array_ptr();
 
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        return api.UsmNDArray_GetNDim_(raw_ar);
    }
 
    const py::ssize_t *get_shape_raw() const
    {
        PyUSMArrayObject *raw_ar = usm_array_ptr();
 
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        return api.UsmNDArray_GetShape_(raw_ar);
    }
 
    std::vector<py::ssize_t> get_shape_vector() const
    {
        auto raw_sh = get_shape_raw();
        auto nd = get_ndim();
 
        std::vector<py::ssize_t> shape_vector(raw_sh, raw_sh + nd);
        return shape_vector;
    }
 
    py::ssize_t get_shape(int i) const
    {
        auto shape_ptr = get_shape_raw();
        return shape_ptr[i];
    }
 
    const py::ssize_t *get_strides_raw() const
    {
        PyUSMArrayObject *raw_ar = usm_array_ptr();
 
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        return api.UsmNDArray_GetStrides_(raw_ar);
    }
 
    std::vector<py::ssize_t> get_strides_vector() const
    {
        auto raw_st = get_strides_raw();
        auto nd = get_ndim();
 
        if (raw_st == nullptr) {
            auto is_c_contig = is_c_contiguous();
            auto is_f_contig = is_f_contiguous();
            auto raw_sh = get_shape_raw();
            if (is_c_contig) {
                const auto &contig_strides = c_contiguous_strides(nd, raw_sh);
                return contig_strides;
            }
            else if (is_f_contig) {
                const auto &contig_strides = f_contiguous_strides(nd, raw_sh);
                return contig_strides;
            }
            else {
                throw std::runtime_error("Invalid array encountered when "
                                         "building strides");
            }
        }
        else {
            std::vector<py::ssize_t> st_vec(raw_st, raw_st + nd);
            return st_vec;
        }
    }
 
    py::ssize_t get_size() const
    {
        PyUSMArrayObject *raw_ar = usm_array_ptr();
 
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        int ndim = api.UsmNDArray_GetNDim_(raw_ar);
        const py::ssize_t *shape = api.UsmNDArray_GetShape_(raw_ar);
 
        py::ssize_t nelems = 1;
        for (int i = 0; i < ndim; ++i) {
            nelems *= shape[i];
        }
 
        assert(nelems >= 0);
        return nelems;
    }
 
    std::pair<py::ssize_t, py::ssize_t> get_minmax_offsets() const
    {
        PyUSMArrayObject *raw_ar = usm_array_ptr();
 
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        int nd = api.UsmNDArray_GetNDim_(raw_ar);
        const py::ssize_t *shape = api.UsmNDArray_GetShape_(raw_ar);
        const py::ssize_t *strides = api.UsmNDArray_GetStrides_(raw_ar);
 
        py::ssize_t offset_min = 0;
        py::ssize_t offset_max = 0;
        if (strides == nullptr) {
            py::ssize_t stride(1);
            for (int i = 0; i < nd; ++i) {
                offset_max += stride * (shape[i] - 1);
                stride *= shape[i];
            }
        }
        else {
            for (int i = 0; i < nd; ++i) {
                py::ssize_t delta = strides[i] * (shape[i] - 1);
                if (strides[i] > 0) {
                    offset_max += delta;
                }
                else {
                    offset_min += delta;
                }
            }
        }
        return std::make_pair(offset_min, offset_max);
    }
 
    sycl::queue get_queue() const
    {
        PyUSMArrayObject *raw_ar = usm_array_ptr();
 
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        DPCTLSyclQueueRef QRef = api.UsmNDArray_GetQueueRef_(raw_ar);
        return *(reinterpret_cast<sycl::queue *>(QRef));
    }
 
    sycl::device get_device() const
    {
        PyUSMArrayObject *raw_ar = usm_array_ptr();
 
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        DPCTLSyclQueueRef QRef = api.UsmNDArray_GetQueueRef_(raw_ar);
        return reinterpret_cast<sycl::queue *>(QRef)->get_device();
    }
 
    int get_typenum() const
    {
        PyUSMArrayObject *raw_ar = usm_array_ptr();
 
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        return api.UsmNDArray_GetTypenum_(raw_ar);
    }
 
    int get_flags() const
    {
        PyUSMArrayObject *raw_ar = usm_array_ptr();
 
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        return api.UsmNDArray_GetFlags_(raw_ar);
    }
 
    int get_elemsize() const
    {
        PyUSMArrayObject *raw_ar = usm_array_ptr();
 
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        return api.UsmNDArray_GetElementSize_(raw_ar);
    }
 
    bool is_c_contiguous() const
    {
        int flags = get_flags();
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        return static_cast<bool>(flags & api.USM_ARRAY_C_CONTIGUOUS_);
    }
 
    bool is_f_contiguous() const
    {
        int flags = get_flags();
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        return static_cast<bool>(flags & api.USM_ARRAY_F_CONTIGUOUS_);
    }
 
    bool is_writable() const
    {
        int flags = get_flags();
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        return static_cast<bool>(flags & api.USM_ARRAY_WRITABLE_);
    }
 
    py::object get_usm_data() const
    {
        PyUSMArrayObject *raw_ar = usm_array_ptr();
 
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        // UsmNDArray_GetUSMData_ gives a new reference
        PyObject *usm_data = api.UsmNDArray_GetUSMData_(raw_ar);
 
        // pass reference ownership to py::object
        return py::reinterpret_steal<py::object>(usm_data);
    }
 
    bool is_managed_by_smart_ptr() const
    {
        PyUSMArrayObject *raw_ar = usm_array_ptr();
 
        auto const &api = ::dpctl::detail::dpctl_capi::get();
        PyObject *usm_data = api.UsmNDArray_GetUSMData_(raw_ar);
 
        if (!PyObject_TypeCheck(usm_data, api.Py_MemoryType_)) {
            Py_DECREF(usm_data);
            return false;
        }
 
        Py_MemoryObject *mem_obj =
            reinterpret_cast<Py_MemoryObject *>(usm_data);
        const void *opaque_ptr = api.Memory_GetOpaquePointer_(mem_obj);
 
        Py_DECREF(usm_data);
        return bool(opaque_ptr);
    }
 
    const std::shared_ptr<void> &get_smart_ptr_owner() const
    {
        PyUSMArrayObject *raw_ar = usm_array_ptr();
 
        auto const &api = ::dpctl::detail::dpctl_capi::get();
 
        PyObject *usm_data = api.UsmNDArray_GetUSMData_(raw_ar);
 
        if (!PyObject_TypeCheck(usm_data, api.Py_MemoryType_)) {
            Py_DECREF(usm_data);
            throw std::runtime_error(
                "usm_ndarray object does not have Memory object "
                "managing lifetime of USM allocation");
        }
 
        Py_MemoryObject *mem_obj =
            reinterpret_cast<Py_MemoryObject *>(usm_data);
        void *opaque_ptr = api.Memory_GetOpaquePointer_(mem_obj);
        Py_DECREF(usm_data);
 
        if (opaque_ptr) {
            auto shptr_ptr =
                reinterpret_cast<std::shared_ptr<void> *>(opaque_ptr);
            return *shptr_ptr;
        }
        else {
            throw std::runtime_error(
                "Memory object underlying usm_ndarray does not have "
                "smart pointer managing lifetime of USM allocation");
        }
    }
 
private:
    PyUSMArrayObject *usm_array_ptr() const
    {
        return reinterpret_cast<PyUSMArrayObject *>(m_ptr);
    }
};
} // end namespace tensor
 
namespace utils
{
namespace detail
{
struct ManagedMemory
{
 
    static bool is_usm_managed_by_shared_ptr(const py::object &h)
    {
        if (py::isinstance<dpctl::memory::usm_memory>(h)) {
            const auto &usm_memory_inst =
                py::cast<dpctl::memory::usm_memory>(h);
            return usm_memory_inst.is_managed_by_smart_ptr();
        }
        else if (py::isinstance<dpctl::tensor::usm_ndarray>(h)) {
            const auto &usm_array_inst =
                py::cast<dpctl::tensor::usm_ndarray>(h);
            return usm_array_inst.is_managed_by_smart_ptr();
        }
 
        return false;
    }
 
    static const std::shared_ptr<void> &extract_shared_ptr(const py::object &h)
    {
        if (py::isinstance<dpctl::memory::usm_memory>(h)) {
            const auto &usm_memory_inst =
                py::cast<dpctl::memory::usm_memory>(h);
            return usm_memory_inst.get_smart_ptr_owner();
        }
        else if (py::isinstance<dpctl::tensor::usm_ndarray>(h)) {
            const auto &usm_array_inst =
                py::cast<dpctl::tensor::usm_ndarray>(h);
            return usm_array_inst.get_smart_ptr_owner();
        }
 
        throw std::runtime_error(
            "Attempted extraction of shared_ptr on an unrecognized type");
    }
};
} // end of namespace detail
 
template <std::size_t num>
sycl::event keep_args_alive(sycl::queue &q,
                            const py::object (&py_objs)[num],
                            const std::vector<sycl::event> &depends = {})
{
    std::size_t n_objects_held = 0;
    std::array<std::shared_ptr<py::handle>, num> shp_arr{};
 
    std::size_t n_usm_owners_held = 0;
    std::array<std::shared_ptr<void>, num> shp_usm{};
 
    for (std::size_t i = 0; i < num; ++i) {
        const auto &py_obj_i = py_objs[i];
        if (detail::ManagedMemory::is_usm_managed_by_shared_ptr(py_obj_i)) {
            const auto &shp =
                detail::ManagedMemory::extract_shared_ptr(py_obj_i);
            shp_usm[n_usm_owners_held] = shp;
            ++n_usm_owners_held;
        }
        else {
            shp_arr[n_objects_held] = std::make_shared<py::handle>(py_obj_i);
            shp_arr[n_objects_held]->inc_ref();
            ++n_objects_held;
        }
    }
 
    bool use_depends = true;
    sycl::event host_task_ev;
 
    if (n_usm_owners_held > 0) {
        host_task_ev = q.submit([&](sycl::handler &cgh) {
            if (use_depends) {
                cgh.depends_on(depends);
                use_depends = false;
            }
            else {
                cgh.depends_on(host_task_ev);
            }
            cgh.host_task([shp_usm = std::move(shp_usm)]() {
                // no body, but shared pointers are captured in
                // the lambda, ensuring that USM allocation is
                // kept alive
            });
        });
    }
 
    if (n_objects_held > 0) {
        host_task_ev = q.submit([&](sycl::handler &cgh) {
            if (use_depends) {
                cgh.depends_on(depends);
                use_depends = false;
            }
            else {
                cgh.depends_on(host_task_ev);
            }
            cgh.host_task([n_objects_held, shp_arr = std::move(shp_arr)]() {
                py::gil_scoped_acquire acquire;
 
                for (std::size_t i = 0; i < n_objects_held; ++i) {
                    shp_arr[i]->dec_ref();
                }
            });
        });
    }
 
    return host_task_ev;
}
 
template <std::size_t num>
bool queues_are_compatible(const sycl::queue &exec_q,
                           const sycl::queue (&alloc_qs)[num])
{
    for (std::size_t i = 0; i < num; ++i) {
 
        if (exec_q != alloc_qs[i]) {
            return false;
        }
    }
    return true;
}
 
template <std::size_t num>
bool queues_are_compatible(const sycl::queue &exec_q,
                           const ::dpctl::tensor::usm_ndarray (&arrs)[num])
{
    for (std::size_t i = 0; i < num; ++i) {
 
        if (exec_q != arrs[i].get_queue()) {
            return false;
        }
    }
    return true;
}
} // end namespace utils
} // end namespace dpctl