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/******************************************************************************
* Copyright (c) 2011-2022, 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::DeviceMemcpy provides device-wide, parallel operations for copying data.
*/
#pragma once
#include <cub/config.cuh>
#if defined(_CCCL_IMPLICIT_SYSTEM_HEADER_GCC)
# pragma GCC system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_CLANG)
# pragma clang system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_MSVC)
# pragma system_header
#endif // no system header
#include <cub/device/dispatch/dispatch_batch_memcpy.cuh>
#include <cstdint>
#include <type_traits>
CUB_NAMESPACE_BEGIN
/**
* @brief cub::DeviceMemcpy provides device-wide, parallel operations for copying data.
* \ingroup SingleModule
*/
struct DeviceMemcpy
{
/**
* @brief Copies data from a batch of given source buffers to their corresponding destination
* buffer.
* @note If any input buffer aliases memory from any output buffer the behavior is undefined. If
* any output buffer aliases memory of another output buffer the behavior is undefined. Input
* buffers can alias one another.
*
* @par Snippet
* The code snippet below illustrates usage of DeviceMemcpy::Batched for mutating strings withing
* a single string buffer.
* @par
* @code
* struct GetPtrToStringItem
* {
* __host__ __device__ __forceinline__ void *operator()(uint32_t index)
* {
* return &d_string_data_in[d_string_offsets[index]];
* }
* char *d_string_data_in;
* uint32_t *d_string_offsets;
* };
*
* struct GetStringItemSize
* {
* __host__ __device__ __forceinline__ uint32_t operator()(uint32_t index)
* {
* return d_string_offsets[index + 1] - d_string_offsets[index];
* }
* uint32_t *d_string_offsets;
* };
*
* uint32_t num_strings = 5;
* char *d_string_data_in; // e.g., "TomatoesBananasApplesOrangesGrapes"
* char *d_string_data_out; // e.g., " ... "
* uint32_t *d_string_offsets_old; // e.g., [0, 8, 15, 21, 28, 34]
* uint32_t *d_string_offsets_new; // e.g., [0, 6, 13, 19, 26, 34]
* uint32_t *d_gather_index; // e.g., [2, 1, 4, 3, 0]
*
* // Initialize an iterator that returns d_gather_index[i] when the i-th item is dereferenced
* auto gather_iterator = thrust::make_permutation_iterator(thrust::make_counting_iterator(0),
* d_gather_index);
*
* // Returns pointers to the input buffer for each string
* auto str_ptrs_in = thrust::make_transform_iterator(gather_iterator,
* GetPtrToStringItem{d_string_data_in,
* d_string_offsets_old});
*
* // Returns the string size of the i-th string
* auto str_sizes = thrust::make_transform_iterator(gather_iterator,
* GetStringItemSize{d_string_offsets_old});
*
* // Returns pointers to the output buffer for each string
* auto str_ptrs_out = thrust::make_transform_iterator(thrust::make_counting_iterator(0),
* GetPtrToStringItem{d_string_data_out,
* d_string_offsets_new});
*
* // Determine temporary device storage requirements
* void *d_temp_storage = nullptr;
* size_t temp_storage_bytes = 0;
* cub::DeviceMemcpy::Batched(d_temp_storage, temp_storage_bytes, str_ptrs_in, str_ptrs_out,
* str_sizes, num_strings);
*
* // Allocate temporary storage
* cudaMalloc(&d_temp_storage, temp_storage_bytes);
*
* // Run batched copy algorithm (used to permute strings)
* cub::DeviceMemcpy::Batched(d_temp_storage, temp_storage_bytes, str_ptrs_in, str_ptrs_out,
* str_sizes, num_strings);
*
* // d_string_data_out <-- "ApplesBananasGrapesOrangesTomatoe"
* @endcode
* @tparam InputBufferIt <b>[inferred]</b> Device-accessible random-access input iterator type
* providing the pointers to the source memory buffers
* @tparam OutputBufferIt <b>[inferred]</b> Device-accessible random-access input iterator type
* providing the pointers to the destination memory buffers
* @tparam BufferSizeIteratorT <b>[inferred]</b> Device-accessible random-access input iterator
* type providing the number of bytes to be copied for each pair of buffers
* @param 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.
* @param temp_storage_bytes [in,out] Reference to size in bytes of \p d_temp_storage allocation
* @param input_buffer_it [in] Device-accessible iterator providing the pointers to the source
* memory buffers
* @param output_buffer_it [in] Device-accessible iterator providing the pointers to the
* destination memory buffers
* @param buffer_sizes [in] Device-accessible iterator providing the number of bytes to be copied
* for each pair of buffers
* @param num_buffers [in] The total number of buffer pairs
* @param stream [in] <b>[optional]</b> CUDA stream to launch kernels within. Default is
* stream<sub>0</sub>.
*/
template <typename InputBufferIt, typename OutputBufferIt, typename BufferSizeIteratorT>
CUB_RUNTIME_FUNCTION static cudaError_t Batched(void *d_temp_storage,
size_t &temp_storage_bytes,
InputBufferIt input_buffer_it,
OutputBufferIt output_buffer_it,
BufferSizeIteratorT buffer_sizes,
uint32_t num_buffers,
cudaStream_t stream = 0)
{
static_assert(std::is_pointer<cub::detail::value_t<InputBufferIt>>::value,
"DeviceMemcpy::Batched only supports copying of memory buffers."
"Please consider using DeviceCopy::Batched instead.");
static_assert(std::is_pointer<cub::detail::value_t<OutputBufferIt>>::value,
"DeviceMemcpy::Batched only supports copying of memory buffers."
"Please consider using DeviceCopy::Batched instead.");
// Integer type large enough to hold any offset in [0, num_buffers)
using BufferOffsetT = uint32_t;
// Integer type large enough to hold any offset in [0, num_thread_blocks_launched), where a safe
// uppper bound on num_thread_blocks_launched can be assumed to be given by
// IDIV_CEIL(num_buffers, 64)
using BlockOffsetT = uint32_t;
return detail::DispatchBatchMemcpy<InputBufferIt,
OutputBufferIt,
BufferSizeIteratorT,
BufferOffsetT,
BlockOffsetT,
detail::DeviceBatchMemcpyPolicy<BufferOffsetT, BlockOffsetT>,
true>::Dispatch(d_temp_storage,
temp_storage_bytes,
input_buffer_it,
output_buffer_it,
buffer_sizes,
num_buffers,
stream);
}
};
CUB_NAMESPACE_END
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