Function CopyHelper

dali/operators/reader/numpy_reader_op.cc:29–50

namespace dali {

static void CopyHelper(SampleView<CPUBackend> output, ConstSampleView<CPUBackend> input,
                       ThreadPool &thread_pool, int min_blk_sz, int req_nblocks) {
  auto *out_ptr = static_cast<uint8_t *>(output.raw_mutable_data());
  const auto *in_ptr = static_cast<const uint8_t *>(input.raw_data());
  auto nelements = input.shape().num_elements();
  auto nbytes = nelements * TypeTable::GetTypeInfo(input.type()).size();
  if (nelements <= min_blk_sz) {
    thread_pool.AddWork([=](int tid) {
      std::memcpy(out_ptr, in_ptr, nbytes);
    }, nelements);
  } else {
    int64_t prev_b_start = 0;
    for (int b = 0; b < req_nblocks; b++) {
      int64_t b_start = prev_b_start;
      int64_t b_end = prev_b_start = nbytes * (b + 1) / req_nblocks;
      int64_t b_size = b_end - b_start;
      thread_pool.AddWork([=](int tid) {
        std::memcpy(out_ptr + b_start, in_ptr + b_start, b_size);
      }, b_size);
    }
  }
}

static void SliceHelper(SampleView<CPUBackend> output, ConstSampleView<CPUBackend> input,
                        const CropWindow &roi, float fill_value, ThreadPool &thread_pool,