/******************************************************************************
 * Copyright (c) 2011, Duane Merrill.  All rights reserved.
 * Copyright (c) 2011-2018, NVIDIA 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.
 *     * Neither the name of the NVIDIA CORPORATION nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL NVIDIA CORPORATION BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 ******************************************************************************/

/**
 * \file
 * cub::DeviceRle provides device-wide, parallel operations for run-length-encoding sequences of data items residing within device-accessible memory.
 */

#pragma once

#include <stdio.h>
#include <iterator>

#include "dispatch_scan.cuh"
#include "../../agent/agent_rle.cuh"
#include "../../thread/thread_operators.cuh"
#include "../../grid/grid_queue.cuh"
#include "../../util_device.cuh"
#include "../../util_namespace.cuh"

/// Optional outer namespace(s)
CUB_NS_PREFIX

/// CUB namespace
namespace cub {


/******************************************************************************
 * Kernel entry points
 *****************************************************************************/

/**
 * Select kernel entry point (multi-block)
 *
 * Performs functor-based selection if SelectOp functor type != NullType
 * Otherwise performs flag-based selection if FlagIterator's value type != NullType
 * Otherwise performs discontinuity selection (keep unique)
 */
template <
    typename            AgentRlePolicyT,        ///< Parameterized AgentRlePolicyT tuning policy type
    typename            InputIteratorT,             ///< Random-access input iterator type for reading input items \iterator
    typename            OffsetsOutputIteratorT,     ///< Random-access output iterator type for writing run-offset values \iterator
    typename            LengthsOutputIteratorT,     ///< Random-access output iterator type for writing run-length values \iterator
    typename            NumRunsOutputIteratorT,     ///< Output iterator type for recording the number of runs encountered \iterator
    typename            ScanTileStateT,              ///< Tile status interface type
    typename            EqualityOpT,                 ///< T equality operator type
    typename            OffsetT>                    ///< Signed integer type for global offsets
__launch_bounds__ (int(AgentRlePolicyT::BLOCK_THREADS))
__global__ void DeviceRleSweepKernel(
    InputIteratorT              d_in,               ///< [in] Pointer to input sequence of data items
    OffsetsOutputIteratorT      d_offsets_out,      ///< [out] Pointer to output sequence of run-offsets
    LengthsOutputIteratorT      d_lengths_out,      ///< [out] Pointer to output sequence of run-lengths
    NumRunsOutputIteratorT      d_num_runs_out,     ///< [out] Pointer to total number of runs (i.e., length of \p d_offsets_out)
    ScanTileStateT              tile_status,        ///< [in] Tile status interface
    EqualityOpT                 equality_op,        ///< [in] Equality operator for input items
    OffsetT                     num_items,          ///< [in] Total number of input items (i.e., length of \p d_in)
    int                         num_tiles)          ///< [in] Total number of tiles for the entire problem
{
    // Thread block type for selecting data from input tiles
    typedef AgentRle<
        AgentRlePolicyT,
        InputIteratorT,
        OffsetsOutputIteratorT,
        LengthsOutputIteratorT,
        EqualityOpT,
        OffsetT> AgentRleT;

    // Shared memory for AgentRle
    __shared__ typename AgentRleT::TempStorage temp_storage;

    // Process tiles
    AgentRleT(temp_storage, d_in, d_offsets_out, d_lengths_out, equality_op, num_items).ConsumeRange(
        num_tiles,
        tile_status,
        d_num_runs_out);
}




/******************************************************************************
 * Dispatch
 ******************************************************************************/

/**
 * Utility class for dispatching the appropriately-tuned kernels for DeviceRle
 */
template <
    typename            InputIteratorT,             ///< Random-access input iterator type for reading input items \iterator
    typename            OffsetsOutputIteratorT,     ///< Random-access output iterator type for writing run-offset values \iterator
    typename            LengthsOutputIteratorT,     ///< Random-access output iterator type for writing run-length values \iterator
    typename            NumRunsOutputIteratorT,     ///< Output iterator type for recording the number of runs encountered \iterator
    typename            EqualityOpT,                ///< T equality operator type
    typename            OffsetT>                    ///< Signed integer type for global offsets
struct DeviceRleDispatch
{
    /******************************************************************************
     * Types and constants
     ******************************************************************************/

    // The input value type
    typedef typename std::iterator_traits<InputIteratorT>::value_type T;

    // The lengths output value type
    typedef typename If<(Equals<typename std::iterator_traits<LengthsOutputIteratorT>::value_type, void>::VALUE),   // LengthT =  (if output iterator's value type is void) ?
        OffsetT,                                                                                                    // ... then the OffsetT type,
        typename std::iterator_traits<LengthsOutputIteratorT>::value_type>::Type LengthT;                           // ... else the output iterator's value type

    enum
    {
        INIT_KERNEL_THREADS = 128,
    };

    // Tile status descriptor interface type
    typedef ReduceByKeyScanTileState<LengthT, OffsetT> ScanTileStateT;


    /******************************************************************************
     * Tuning policies
     ******************************************************************************/

    /// SM35
    struct Policy350
    {
        enum {
            NOMINAL_4B_ITEMS_PER_THREAD = 15,
            ITEMS_PER_THREAD            = CUB_MIN(NOMINAL_4B_ITEMS_PER_THREAD, CUB_MAX(1, (NOMINAL_4B_ITEMS_PER_THREAD * 4 / sizeof(T)))),
        };

        typedef AgentRlePolicy<
                96,
                ITEMS_PER_THREAD,
                BLOCK_LOAD_DIRECT,
                LOAD_LDG,
                true,
                BLOCK_SCAN_WARP_SCANS>
            RleSweepPolicy;
    };

    /// SM30
    struct Policy300
    {
        enum {
            NOMINAL_4B_ITEMS_PER_THREAD = 5,
            ITEMS_PER_THREAD            = CUB_MIN(NOMINAL_4B_ITEMS_PER_THREAD, CUB_MAX(1, (NOMINAL_4B_ITEMS_PER_THREAD * 4 / sizeof(T)))),
        };

        typedef AgentRlePolicy<
                256,
                ITEMS_PER_THREAD,
                BLOCK_LOAD_WARP_TRANSPOSE,
                LOAD_DEFAULT,
                true,
                BLOCK_SCAN_RAKING_MEMOIZE>
            RleSweepPolicy;
    };

    /// SM20
    struct Policy200
    {
        enum {
            NOMINAL_4B_ITEMS_PER_THREAD = 15,
            ITEMS_PER_THREAD            = CUB_MIN(NOMINAL_4B_ITEMS_PER_THREAD, CUB_MAX(1, (NOMINAL_4B_ITEMS_PER_THREAD * 4 / sizeof(T)))),
        };

        typedef AgentRlePolicy<
                128,
                ITEMS_PER_THREAD,
                BLOCK_LOAD_WARP_TRANSPOSE,
                LOAD_DEFAULT,
                false,
                BLOCK_SCAN_WARP_SCANS>
            RleSweepPolicy;
    };

    /// SM13
    struct Policy130
    {
        enum {
            NOMINAL_4B_ITEMS_PER_THREAD = 9,
            ITEMS_PER_THREAD            = CUB_MIN(NOMINAL_4B_ITEMS_PER_THREAD, CUB_MAX(1, (NOMINAL_4B_ITEMS_PER_THREAD * 4 / sizeof(T)))),
        };

        typedef AgentRlePolicy<
                64,
                ITEMS_PER_THREAD,
                BLOCK_LOAD_WARP_TRANSPOSE,
                LOAD_DEFAULT,
                true,
                BLOCK_SCAN_RAKING_MEMOIZE>
            RleSweepPolicy;
    };

    /// SM10
    struct Policy100
    {
        enum {
            NOMINAL_4B_ITEMS_PER_THREAD = 9,
            ITEMS_PER_THREAD            = CUB_MIN(NOMINAL_4B_ITEMS_PER_THREAD, CUB_MAX(1, (NOMINAL_4B_ITEMS_PER_THREAD * 4 / sizeof(T)))),
        };

        typedef AgentRlePolicy<
                256,
                ITEMS_PER_THREAD,
                BLOCK_LOAD_WARP_TRANSPOSE,
                LOAD_DEFAULT,
                true,
                BLOCK_SCAN_RAKING_MEMOIZE>
            RleSweepPolicy;
    };


    /******************************************************************************
     * Tuning policies of current PTX compiler pass
     ******************************************************************************/

#if (CUB_PTX_ARCH >= 350)
    typedef Policy350 PtxPolicy;

#elif (CUB_PTX_ARCH >= 300)
    typedef Policy300 PtxPolicy;

#elif (CUB_PTX_ARCH >= 200)
    typedef Policy200 PtxPolicy;

#elif (CUB_PTX_ARCH >= 130)
    typedef Policy130 PtxPolicy;

#else
    typedef Policy100 PtxPolicy;

#endif

    // "Opaque" policies (whose parameterizations aren't reflected in the type signature)
    struct PtxRleSweepPolicy : PtxPolicy::RleSweepPolicy {};


    /******************************************************************************
     * Utilities
     ******************************************************************************/

    /**
     * Initialize kernel dispatch configurations with the policies corresponding to the PTX assembly we will use
     */
    template <typename KernelConfig>
    CUB_RUNTIME_FUNCTION __forceinline__
    static void InitConfigs(
        int             ptx_version,
        KernelConfig&   device_rle_config)
    {
    #if (CUB_PTX_ARCH > 0)

        // We're on the device, so initialize the kernel dispatch configurations with the current PTX policy
        device_rle_config.template Init<PtxRleSweepPolicy>();

    #else

        // We're on the host, so lookup and initialize the kernel dispatch configurations with the policies that match the device's PTX version
        if (ptx_version >= 350)
        {
            device_rle_config.template Init<typename Policy350::RleSweepPolicy>();
        }
        else if (ptx_version >= 300)
        {
            device_rle_config.template Init<typename Policy300::RleSweepPolicy>();
        }
        else if (ptx_version >= 200)
        {
            device_rle_config.template Init<typename Policy200::RleSweepPolicy>();
        }
        else if (ptx_version >= 130)
        {
            device_rle_config.template Init<typename Policy130::RleSweepPolicy>();
        }
        else
        {
            device_rle_config.template Init<typename Policy100::RleSweepPolicy>();
        }

    #endif
    }


    /**
     * Kernel kernel dispatch configuration.  Mirrors the constants within AgentRlePolicyT.
     */
    struct KernelConfig
    {
        int                     block_threads;
        int                     items_per_thread;
        BlockLoadAlgorithm      load_policy;
        bool                    store_warp_time_slicing;
        BlockScanAlgorithm      scan_algorithm;

        template <typename AgentRlePolicyT>
        CUB_RUNTIME_FUNCTION __forceinline__
        void Init()
        {
            block_threads               = AgentRlePolicyT::BLOCK_THREADS;
            items_per_thread            = AgentRlePolicyT::ITEMS_PER_THREAD;
            load_policy                 = AgentRlePolicyT::LOAD_ALGORITHM;
            store_warp_time_slicing     = AgentRlePolicyT::STORE_WARP_TIME_SLICING;
            scan_algorithm              = AgentRlePolicyT::SCAN_ALGORITHM;
        }

        CUB_RUNTIME_FUNCTION __forceinline__
        void Print()
        {
            printf("%d, %d, %d, %d, %d",
                block_threads,
                items_per_thread,
                load_policy,
                store_warp_time_slicing,
                scan_algorithm);
        }
    };


    /******************************************************************************
     * Dispatch entrypoints
     ******************************************************************************/

    /**
     * Internal dispatch routine for computing a device-wide run-length-encode using the
     * specified kernel functions.
     */
    template <
        typename                    DeviceScanInitKernelPtr,        ///< Function type of cub::DeviceScanInitKernel
        typename                    DeviceRleSweepKernelPtr>        ///< Function type of cub::DeviceRleSweepKernelPtr
    CUB_RUNTIME_FUNCTION __forceinline__
    static cudaError_t Dispatch(
        void*                       d_temp_storage,                 ///< [in] %Device-accessible allocation of temporary storage.  When NULL, the required allocation size is written to \p temp_storage_bytes and no work is done.
        size_t&                     temp_storage_bytes,             ///< [in,out] Reference to size in bytes of \p d_temp_storage allocation
        InputIteratorT              d_in,                           ///< [in] Pointer to the input sequence of data items
        OffsetsOutputIteratorT      d_offsets_out,                  ///< [out] Pointer to the output sequence of run-offsets
        LengthsOutputIteratorT      d_lengths_out,                  ///< [out] Pointer to the output sequence of run-lengths
        NumRunsOutputIteratorT      d_num_runs_out,                 ///< [out] Pointer to the total number of runs encountered (i.e., length of \p d_offsets_out)
        EqualityOpT                 equality_op,                    ///< [in] Equality operator for input items
        OffsetT                     num_items,                      ///< [in] Total number of input items (i.e., length of \p d_in)
        cudaStream_t                stream,                         ///< [in] CUDA stream to launch kernels within.  Default is stream<sub>0</sub>.
        bool                        debug_synchronous,              ///< [in] Whether or not to synchronize the stream after every kernel launch to check for errors.  Also causes launch configurations to be printed to the console.  Default is \p false.
        int                         ptx_version,                    ///< [in] PTX version of dispatch kernels
        DeviceScanInitKernelPtr     device_scan_init_kernel,        ///< [in] Kernel function pointer to parameterization of cub::DeviceScanInitKernel
        DeviceRleSweepKernelPtr     device_rle_sweep_kernel,        ///< [in] Kernel function pointer to parameterization of cub::DeviceRleSweepKernel
        KernelConfig                device_rle_config)              ///< [in] Dispatch parameters that match the policy that \p device_rle_sweep_kernel was compiled for
    {

#ifndef CUB_RUNTIME_ENABLED

        // Kernel launch not supported from this device
        return CubDebug(cudaErrorNotSupported);

#else

        cudaError error = cudaSuccess;
        do
        {
            // Get device ordinal
            int device_ordinal;
            if (CubDebug(error = cudaGetDevice(&device_ordinal))) break;

            // Get SM count
            int sm_count;
            if (CubDebug(error = cudaDeviceGetAttribute (&sm_count, cudaDevAttrMultiProcessorCount, device_ordinal))) break;

            // Number of input tiles
            int tile_size = device_rle_config.block_threads * device_rle_config.items_per_thread;
            int num_tiles = (num_items + tile_size - 1) / tile_size;

            // Specify temporary storage allocation requirements
            size_t  allocation_sizes[1];
            if (CubDebug(error = ScanTileStateT::AllocationSize(num_tiles, allocation_sizes[0]))) break;    // bytes needed for tile status descriptors

            // Compute allocation pointers into the single storage blob (or compute the necessary size of the blob)
            void* allocations[1];
            if (CubDebug(error = AliasTemporaries(d_temp_storage, temp_storage_bytes, allocations, allocation_sizes))) break;
            if (d_temp_storage == NULL)
            {
                // Return if the caller is simply requesting the size of the storage allocation
                break;
            }

            // Construct the tile status interface
            ScanTileStateT tile_status;
            if (CubDebug(error = tile_status.Init(num_tiles, allocations[0], allocation_sizes[0]))) break;

            // Log device_scan_init_kernel configuration
            int init_grid_size = CUB_MAX(1, (num_tiles + INIT_KERNEL_THREADS - 1) / INIT_KERNEL_THREADS);
            if (debug_synchronous) _CubLog("Invoking device_scan_init_kernel<<<%d, %d, 0, %lld>>>()\n", init_grid_size, INIT_KERNEL_THREADS, (long long) stream);

            // Invoke device_scan_init_kernel to initialize tile descriptors and queue descriptors
            device_scan_init_kernel<<<init_grid_size, INIT_KERNEL_THREADS, 0, stream>>>(
                tile_status,
                num_tiles,
                d_num_runs_out);

            // Check for failure to launch
            if (CubDebug(error = cudaPeekAtLastError())) break;

            // Sync the stream if specified to flush runtime errors
            if (debug_synchronous && (CubDebug(error = SyncStream(stream)))) break;

            // Return if empty problem
            if (num_items == 0)
                break;

            // Get SM occupancy for device_rle_sweep_kernel
            int device_rle_kernel_sm_occupancy;
            if (CubDebug(error = MaxSmOccupancy(
                device_rle_kernel_sm_occupancy,            // out
                device_rle_sweep_kernel,
                device_rle_config.block_threads))) break;

            // Get max x-dimension of grid
            int max_dim_x;
            if (CubDebug(error = cudaDeviceGetAttribute(&max_dim_x, cudaDevAttrMaxGridDimX, device_ordinal))) break;;

            // Get grid size for scanning tiles
            dim3 scan_grid_size;
            scan_grid_size.z = 1;
            scan_grid_size.y = ((unsigned int) num_tiles + max_dim_x - 1) / max_dim_x;
            scan_grid_size.x = CUB_MIN(num_tiles, max_dim_x);

            // Log device_rle_sweep_kernel configuration
            if (debug_synchronous) _CubLog("Invoking device_rle_sweep_kernel<<<{%d,%d,%d}, %d, 0, %lld>>>(), %d items per thread, %d SM occupancy\n",
                scan_grid_size.x, scan_grid_size.y, scan_grid_size.z, device_rle_config.block_threads, (long long) stream, device_rle_config.items_per_thread, device_rle_kernel_sm_occupancy);

            // Invoke device_rle_sweep_kernel
            device_rle_sweep_kernel<<<scan_grid_size, device_rle_config.block_threads, 0, stream>>>(
                d_in,
                d_offsets_out,
                d_lengths_out,
                d_num_runs_out,
                tile_status,
                equality_op,
                num_items,
                num_tiles);

            // Check for failure to launch
            if (CubDebug(error = cudaPeekAtLastError())) break;

            // Sync the stream if specified to flush runtime errors
            if (debug_synchronous && (CubDebug(error = SyncStream(stream)))) break;

        }
        while (0);

        return error;

#endif  // CUB_RUNTIME_ENABLED
    }


    /**
     * Internal dispatch routine
     */
    CUB_RUNTIME_FUNCTION __forceinline__
    static cudaError_t Dispatch(
        void*                       d_temp_storage,                 ///< [in] %Device-accessible allocation of temporary storage.  When NULL, the required allocation size is written to \p temp_storage_bytes and no work is done.
        size_t&                     temp_storage_bytes,             ///< [in,out] Reference to size in bytes of \p d_temp_storage allocation
        InputIteratorT              d_in,                           ///< [in] Pointer to input sequence of data items
        OffsetsOutputIteratorT      d_offsets_out,                  ///< [out] Pointer to output sequence of run-offsets
        LengthsOutputIteratorT      d_lengths_out,                  ///< [out] Pointer to output sequence of run-lengths
        NumRunsOutputIteratorT      d_num_runs_out,                 ///< [out] Pointer to total number of runs (i.e., length of \p d_offsets_out)
        EqualityOpT                 equality_op,                    ///< [in] Equality operator for input items
        OffsetT                     num_items,                      ///< [in] Total number of input items (i.e., length of \p d_in)
        cudaStream_t                stream,                         ///< [in] <b>[optional]</b> CUDA stream to launch kernels within.  Default is stream<sub>0</sub>.
        bool                        debug_synchronous)              ///< [in] <b>[optional]</b> Whether or not to synchronize the stream after every kernel launch to check for errors.  Also causes launch configurations to be printed to the console.  Default is \p false.
    {
        cudaError error = cudaSuccess;
        do
        {
            // Get PTX version
            int ptx_version;
    #if (CUB_PTX_ARCH == 0)
            if (CubDebug(error = PtxVersion(ptx_version))) break;
    #else
            ptx_version = CUB_PTX_ARCH;
    #endif

            // Get kernel kernel dispatch configurations
            KernelConfig device_rle_config;
            InitConfigs(ptx_version, device_rle_config);

            // Dispatch
            if (CubDebug(error = Dispatch(
                d_temp_storage,
                temp_storage_bytes,
                d_in,
                d_offsets_out,
                d_lengths_out,
                d_num_runs_out,
                equality_op,
                num_items,
                stream,
                debug_synchronous,
                ptx_version,
                DeviceCompactInitKernel<ScanTileStateT, NumRunsOutputIteratorT>,
                DeviceRleSweepKernel<PtxRleSweepPolicy, InputIteratorT, OffsetsOutputIteratorT, LengthsOutputIteratorT, NumRunsOutputIteratorT, ScanTileStateT, EqualityOpT, OffsetT>,
                device_rle_config))) break;
        }
        while (0);

        return error;
    }
};


}               // CUB namespace
CUB_NS_POSTFIX  // Optional outer namespace(s)