C++ array::get_ndo方法代码示例

static nd::array array_function_dereference(const nd::array &self)
{
  // Follow the pointers to eliminate them
  ndt::type dt = self.get_type();
  const char *arrmeta = self.get_arrmeta();
  char *data = self.get_ndo()->m_data_pointer;
  memory_block_data *dataref = self.get_ndo()->m_data_reference;
  if (dataref == NULL) {
    dataref = self.get_memblock().get();
  }
  uint64_t flags = self.get_ndo()->m_flags;

  while (dt.get_type_id() == pointer_type_id) {
    const pointer_type_arrmeta *md =
        reinterpret_cast<const pointer_type_arrmeta *>(arrmeta);
    dt = dt.extended<ndt::pointer_type>()->get_target_type();
    arrmeta += sizeof(pointer_type_arrmeta);
    data = *reinterpret_cast<char **>(data) + md->offset;
    dataref = md->blockref;
  }

  // Create an array without the pointers
  nd::array result(make_array_memory_block(dt.get_arrmeta_size()));
  if (!dt.is_builtin()) {
    dt.extended()->arrmeta_copy_construct(result.get_arrmeta(), arrmeta,
                                          &self.get_ndo()->m_memblockdata);
  }
  result.get_ndo()->m_type = dt.release();
  result.get_ndo()->m_data_pointer = data;
  result.get_ndo()->m_data_reference = dataref;
  memory_block_incref(result.get_ndo()->m_data_reference);
  result.get_ndo()->m_flags = flags;
  return result;
}

nd::array nd::view(const nd::array& arr, const ndt::type& tp)
{
    // If the types match exactly, simply return 'arr'
    if (arr.get_type() == tp) {
        return arr;
    } else if (arr.get_ndim() == tp.get_ndim()) {
        // Allocate a result array to attempt the view in it
        array result(make_array_memory_block(tp.get_metadata_size()));
        // Copy the fields
        result.get_ndo()->m_data_pointer = arr.get_ndo()->m_data_pointer;
        if (arr.get_ndo()->m_data_reference == NULL) {
            // Embedded data, need reference to the array
            result.get_ndo()->m_data_reference = arr.get_memblock().release();
        } else {
            // Use the same data reference, avoid producing a chain
            result.get_ndo()->m_data_reference = arr.get_data_memblock().release();
        }
        result.get_ndo()->m_type = ndt::type(tp).release();
        result.get_ndo()->m_flags = arr.get_ndo()->m_flags;
        // Now try to copy the metadata as a view
        if (try_view(arr.get_type(), arr.get_ndo_meta(), tp,
                     result.get_ndo_meta(), arr.get_memblock().get())) {
            // If it succeeded, return it
            return result;
        }
        // Otherwise fall through, let it get destructed, and raise an error
    }

    stringstream ss;
    ss << "Unable to view nd::array of type " << arr.get_type();
    ss << "as type " << tp;
    throw type_error(ss.str());
}

static nd::array view_concrete(const nd::array &arr, const ndt::type &tp)
{
  // Allocate a result array to attempt the view in it
  nd::array result(make_array_memory_block(tp.get_arrmeta_size()));
  // Copy the fields
  result.get_ndo()->data.ptr = arr.get_ndo()->data.ptr;
  if (arr.get_ndo()->data.ref == NULL) {
    // Embedded data, need reference to the array
    result.get_ndo()->data.ref = arr.get_memblock().release();
  } else {
    // Use the same data reference, avoid producing a chain
    result.get_ndo()->data.ref = arr.get_data_memblock().release();
  }
  result.get_ndo()->m_type = ndt::type(tp).release();
  result.get_ndo()->m_flags = arr.get_ndo()->m_flags;
  // First handle a special case of viewing outermost "var" as "fixed[#]"
  if (arr.get_type().get_type_id() == var_dim_type_id && tp.get_type_id() == fixed_dim_type_id) {
    const var_dim_type_arrmeta *in_am = reinterpret_cast<const var_dim_type_arrmeta *>(arr.get_arrmeta());
    const var_dim_type_data *in_dat = reinterpret_cast<const var_dim_type_data *>(arr.get_readonly_originptr());
    fixed_dim_type_arrmeta *out_am = reinterpret_cast<fixed_dim_type_arrmeta *>(result.get_arrmeta());
    out_am->dim_size = tp.extended<ndt::fixed_dim_type>()->get_fixed_dim_size();
    out_am->stride = in_am->stride;
    if ((intptr_t)in_dat->size == out_am->dim_size) {
      // Use the more specific data reference from the var arrmeta if possible
      if (in_am->blockref != NULL) {
        memory_block_decref(result.get_ndo()->data.ref);
        memory_block_incref(in_am->blockref);
        result.get_ndo()->data.ref = in_am->blockref;
      }
      result.get_ndo()->data.ptr = in_dat->begin + in_am->offset;
      // Try to copy the rest of the arrmeta as a view
      if (try_view(arr.get_type().extended<ndt::base_dim_type>()->get_element_type(),
                   arr.get_arrmeta() + sizeof(var_dim_type_arrmeta),
                   tp.extended<ndt::base_dim_type>()->get_element_type(),
                   result.get_arrmeta() + sizeof(fixed_dim_type_arrmeta), arr.get_memblock().get())) {
        return result;
      }
    }
  }
  // Otherwise try to copy the arrmeta as a view
  else if (try_view(arr.get_type(), arr.get_arrmeta(), tp, result.get_arrmeta(), arr.get_memblock().get())) {
    // If it succeeded, return it
    return result;
  }

  stringstream ss;
  ss << "Unable to view nd::array of type " << arr.get_type();
  ss << " as type " << tp;
  throw type_error(ss.str());
}

 static void set(const ndt::type& paramtype, char *metadata, char *data, const nd::array& value) {
     if (paramtype.get_type_id() == void_pointer_type_id) {
         // TODO: switch to a better mechanism for passing nd::array references
         *reinterpret_cast<const array_preamble **>(data) = value.get_ndo();
     } else {
         typed_data_assign(paramtype, metadata, data, value.get_type(), value.get_ndo_meta(), value.get_ndo()->m_data_pointer);
     }
 }

/**
 * Given a buffer array of type "strided * T" which was
 * created by nd::empty, resets it so it can be used
 * as a buffer again.
 *
 * NOTE: If the array is not of type "strided * T" and default
 *       initialized by nd::empty, undefined behavior will result.
 * 
 */
inline void reset_strided_buffer_array(const nd::array& buf)
{
  const ndt::type &buf_tp = buf.get_type();
  base_type_members::flags_type flags = buf_tp.extended()->get_flags();
  if (flags &
      (type_flag_blockref | type_flag_zeroinit | type_flag_destructor)) {
    char *buf_arrmeta = buf.get_ndo()->get_arrmeta();
    char *buf_data = buf.get_readwrite_originptr();
    buf_tp.extended()->arrmeta_reset_buffers(buf.get_ndo()->get_arrmeta());
    strided_dim_type_arrmeta *am =
        reinterpret_cast<strided_dim_type_arrmeta *>(buf_arrmeta);
    if (flags & type_flag_destructor) {
      buf_tp.extended()->data_destruct(buf_arrmeta, buf_data);
    }
    memset(buf_data, 0, am->dim_size * am->stride);
  }
}

static nd::array view_as_bytes(const nd::array &arr, const ndt::type &tp)
{
  if (arr.get_type().get_flags() & type_flag_destructor) {
    // Can't view arrays of object type
    return nd::array();
  }

  // Get the essential components of the array to analyze
  memory_block_ptr data_ref = arr.get_data_memblock();
  char *data_ptr = arr.get_ndo()->data.ptr;
  ndt::type data_tp = arr.get_type();
  const char *data_meta = arr.get_arrmeta();
  intptr_t data_dim_size = -1, data_stride = 0;
  // Repeatedly refine the data
  while (data_tp.get_type_id() != uninitialized_type_id) {
    refine_bytes_view(data_ref, data_ptr, data_tp, data_meta, data_dim_size, data_stride);
  }
  // Check that it worked, and that the resulting data pointer is aligned
  if (data_dim_size < 0 ||
      !offset_is_aligned(reinterpret_cast<size_t>(data_ptr), tp.extended<ndt::bytes_type>()->get_target_alignment())) {
    // This signals we could not view the data as a
    // contiguous chunk of bytes
    return nd::array();
  }

  char *result_data_ptr = NULL;
  nd::array result(make_array_memory_block(tp.extended()->get_arrmeta_size(), tp.get_data_size(),
                                           tp.get_data_alignment(), &result_data_ptr));
  // Set the bytes extents
  ((char **)result_data_ptr)[0] = data_ptr;
  ((char **)result_data_ptr)[1] = data_ptr + data_dim_size;
  // Set the array arrmeta
  array_preamble *ndo = result.get_ndo();
  ndo->m_type = ndt::type(tp).release();
  ndo->data.ptr = result_data_ptr;
  ndo->data.ref = NULL;
  ndo->m_flags = arr.get_flags();
  // Set the bytes arrmeta
  bytes_type_arrmeta *ndo_meta = reinterpret_cast<bytes_type_arrmeta *>(result.get_arrmeta());
  ndo_meta->blockref = data_ref.release();
  return result;
}

dynd::nd::array pydynd::nd_fields(const nd::array& n, PyObject *field_list)
{
    vector<string> selected_fields;
    pyobject_as_vector_string(field_list, selected_fields);

    // TODO: Move this implementation into dynd
    ndt::type fdt = n.get_dtype();
    if (fdt.get_kind() != struct_kind) {
        stringstream ss;
        ss << "nd.fields must be given a dynd array of 'struct' kind, not ";
        ss << fdt;
        throw runtime_error(ss.str());
    }
    const base_struct_type *bsd = static_cast<const base_struct_type *>(fdt.extended());
    const ndt::type *field_types = bsd->get_field_types();

    if (selected_fields.empty()) {
        throw runtime_error("nd.fields requires at least one field name to be specified");
    }
    // Construct the field mapping and output field types
    vector<intptr_t> selected_index(selected_fields.size());
    vector<ndt::type> selected_ndt_types(selected_fields.size());
    for (size_t i = 0; i != selected_fields.size(); ++i) {
        selected_index[i] = bsd->get_field_index(selected_fields[i]);
        if (selected_index[i] < 0) {
            stringstream ss;
            ss << "field name ";
            print_escaped_utf8_string(ss, selected_fields[i]);
            ss << " does not exist in dynd type " << fdt;
            throw runtime_error(ss.str());
        }
        selected_ndt_types[i] = field_types[selected_index[i]];
    }
    // Create the result udt
    ndt::type rudt = ndt::make_struct(selected_ndt_types, selected_fields);
    ndt::type result_tp = n.get_type().with_replaced_dtype(rudt);
    const base_struct_type *rudt_bsd = static_cast<const base_struct_type *>(rudt.extended());

    // Allocate the new memory block.
    size_t metadata_size = result_tp.get_metadata_size();
    nd::array result(make_array_memory_block(metadata_size));

    // Clone the data pointer
    result.get_ndo()->m_data_pointer = n.get_ndo()->m_data_pointer;
    result.get_ndo()->m_data_reference = n.get_ndo()->m_data_reference;
    if (result.get_ndo()->m_data_reference == NULL) {
        result.get_ndo()->m_data_reference = n.get_memblock().get();
    }
    memory_block_incref(result.get_ndo()->m_data_reference);

    // Copy the flags
    result.get_ndo()->m_flags = n.get_ndo()->m_flags;

    // Set the type and transform the metadata
    result.get_ndo()->m_type = ndt::type(result_tp).release();
    // First copy all the array data type metadata
    ndt::type tmp_dt = result_tp;
    char *dst_metadata = result.get_ndo_meta();
    const char *src_metadata = n.get_ndo_meta();
    while (tmp_dt.get_ndim() > 0) {
        if (tmp_dt.get_kind() != uniform_dim_kind) {
            throw runtime_error("nd.fields doesn't support dimensions with pointers yet");
        }
        const base_uniform_dim_type *budd = static_cast<const base_uniform_dim_type *>(
                        tmp_dt.extended());
        size_t offset = budd->metadata_copy_construct_onedim(dst_metadata, src_metadata,
                        n.get_memblock().get());
        dst_metadata += offset;
        src_metadata += offset;
        tmp_dt = budd->get_element_type();
    }
    // Then create the metadata for the new struct
    const size_t *metadata_offsets = bsd->get_metadata_offsets();
    const size_t *result_metadata_offsets = rudt_bsd->get_metadata_offsets();
    const size_t *data_offsets = bsd->get_data_offsets(src_metadata);
    size_t *result_data_offsets = reinterpret_cast<size_t *>(dst_metadata);
    for (size_t i = 0; i != selected_fields.size(); ++i) {
        const ndt::type& dt = selected_ndt_types[i];
        // Copy the data offset
        result_data_offsets[i] = data_offsets[selected_index[i]];
        // Copy the metadata for this field
        if (dt.get_metadata_size() > 0) {
            dt.extended()->metadata_copy_construct(dst_metadata + result_metadata_offsets[i],
                            src_metadata + metadata_offsets[selected_index[i]],
                            n.get_memblock().get());
        }
    }

    return result;
}