/*!
 *  Copyright (c) 2017 by Contributors
 * \file dlpack.h
 * \brief The common header of DLPack.
 */

// Copied from pytorch/torch/lib/ATen/dlpack.h

#ifndef DLPACK_DLPACK_H_
#define DLPACK_DLPACK_H_

#ifdef __cplusplus
#define DLPACK_EXTERN_C extern "C"
#else
#define DLPACK_EXTERN_C
#endif

/*! \brief The current version of dlpack */
#define DLPACK_VERSION 010

/*! \brief DLPACK_DLL prefix for windows */
#ifdef _WIN32
#ifdef DLPACK_EXPORTS
#define DLPACK_DLL __declspec(dllexport)
#else
#define DLPACK_DLL __declspec(dllimport)
#endif
#else
#define DLPACK_DLL
#endif

#include <stdint.h>
#include <stddef.h>

#ifdef __cplusplus
extern "C" {
#endif
/*!
 * \brief The device type in DLContext.
 */
typedef enum {
  kCPU = 1,
  kGPU = 2,
  // kCPUPinned = kCPU | kGPU
  kCPUPinned = 3,
  kOpenCL = 4,
  kMetal = 8,
  kVPI = 9,
  kROCM = 10,
} DLDeviceType;

/*!
 * \brief A Device context for Tensor and operator.
 */
typedef struct {
  /*! \brief The device type used in the device. */
  DLDeviceType device_type;
  /*! \brief The device index */
  int device_id;
} DLContext;

/*!
 * \brief The type code options DLDataType.
 */
typedef enum {
  kInt = 0U,
  kUInt = 1U,
  kFloat = 2U,
} DLDataTypeCode;

/*!
 * \brief The data type the tensor can hold.
 *
 *  Examples
 *   - float: type_code = 2, bits = 32, lanes=1
 *   - float4(vectorized 4 float): type_code = 2, bits = 32, lanes=4
 *   - int8: type_code = 0, bits = 8, lanes=1
 */
typedef struct {
  /*!
   * \brief Type code of base types.
   * We keep it uint8_t instead of DLDataTypeCode for minimal memory
   * footprint, but the value should be one of DLDataTypeCode enum values.
   * */
  uint8_t code;
  /*!
   * \brief Number of bits, common choices are 8, 16, 32.
   */
  uint8_t bits;
  /*! \brief Number of lanes in the type, used for vector types. */
  uint16_t lanes;
} DLDataType;

/*!
 * \brief Plain C Tensor object, does not manage memory.
 */
typedef struct {
  /*!
   * \brief The opaque data pointer points to the allocated data.
   *  This will be CUDA device pointer or cl_mem handle in OpenCL.
   *  This pointer is always aligns to 256 bytes as in CUDA.
   */
  void* data;
  /*! \brief The device context of the tensor */
  DLContext ctx;
  /*! \brief Number of dimensions */
  int ndim;
  /*! \brief The data type of the pointer*/
  DLDataType dtype;
  /*! \brief The shape of the tensor */
  int64_t* shape;
  /*!
   * \brief strides of the tensor,
   *  can be NULL, indicating tensor is compact.
   */
  int64_t* strides;
  /*! \brief The offset in bytes to the beginning pointer to data */
  uint64_t byte_offset;
} DLTensor;

/*!
 * \brief C Tensor object, manage memory of DLTensor.
 */
typedef struct DLManagedTensor {
  /*! \DLTensor which is being memory managed */
  DLTensor dlTensor;
  /*! \brief context in which DLManagedTensor is used in a framework. It can
   *   also be NULL
   */
  void * ctx;
  /*! \brief Destructor signature void (*)(void*) - this should be called
   *   to destruct ctx which holds the DLManagedTensor. It can be NULL if there
   *   is no way for the caller to provide a reasonable destructor.
   */
  void (*destructor)(DLManagedTensor * self);
} DLManagedTensor;

#ifdef __cplusplus
}  // DLPACK_EXTERN_C
#endif
#endif  // DLPACK_DLPACK_H_