docs/source/cpp/api/utilities.rst
.. Licensed to the Apache Software Foundation (ASF) under one .. or more contributor license agreements. See the NOTICE file .. distributed with this work for additional information .. regarding copyright ownership. The ASF licenses this file .. to you under the Apache License, Version 2.0 (the .. "License"); you may not use this file except in compliance .. with the License. You may obtain a copy of the License at
.. http://www.apache.org/licenses/LICENSE-2.0
.. Unless required by applicable law or agreed to in writing, .. software distributed under the License is distributed on an .. "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY .. KIND, either express or implied. See the License for the .. specific language governing permissions and limitations .. under the License.
.. doxygenclass:: arrow::BasicDecimal128 :members:
.. doxygenclass:: arrow::Decimal128 :members:
.. doxygenclass:: arrow::BasicDecimal256 :members:
.. doxygenclass:: arrow::Decimal256 :members:
.. doxygenclass:: arrow::Iterator :members:
.. doxygenclass:: arrow::VectorIterator :members:
.. doxygenclass:: arrow::EqualOptions :members:
.. doxygenenum:: arrow::Compression::type
.. doxygenclass:: arrow::util::Codec :members:
.. doxygenclass:: arrow::util::Compressor :members:
.. doxygenclass:: arrow::util::Decompressor :members:
.. doxygenfunction:: arrow::VisitTypeInline :project: arrow_cpp
.. doxygenfunction:: arrow::VisitTypeIdInline :project: arrow_cpp
.. doxygenfunction:: arrow::VisitScalarInline :project: arrow_cpp
.. doxygenfunction:: arrow::VisitArrayInline :project: arrow_cpp
.. _type-traits:
These types provide relationships between Arrow types at compile
time. :cpp:type:TypeTraits maps Arrow DataTypes to other types, and
:cpp:type:CTypeTraits maps C types to Arrow types.
Each specialized type defines the following associated types:
.. cpp:type:: TypeTraits::ArrayType
Corresponding :doc:Arrow array type <./array>
.. cpp:type:: TypeTraits::BuilderType
Corresponding :doc:array builder type <./builder>
.. cpp:type:: TypeTraits::ScalarType
Corresponding :doc:Arrow scalar type <./scalar>
.. cpp:var:: bool TypeTraits::is_parameter_free
Whether the type has any type parameters, such as field types in nested types or scale and precision in decimal types.
In addition, the following are defined for many but not all of the types:
.. cpp:type:: TypeTraits::CType
Corresponding C type. For example, int64_t for Int64Array.
.. cpp:type:: TypeTraits::TensorType
Corresponding :doc:Arrow tensor type <./tensor>
.. cpp:function:: static inline constexpr int64_t bytes_required(int64_t elements)
Return the number of bytes required for given number of elements. Defined for types with a fixed size.
.. cpp:function:: static inline std::shared_ptr<DataType> TypeTraits::type_singleton()
For types where is_parameter_free is true, returns an instance of the data type.
.. doxygengroup:: type-traits :content-only: :members: :undoc-members:
Each specialized type defines the following associated types:
.. cpp:type:: CTypeTraits::ArrowType
Corresponding :doc:Arrow type <./datatype>
.. doxygengroup:: c-type-traits :content-only: :members: :undoc-members:
.. _type-predicates-api:
Type predicates that can be used with templates. Predicates of the form is_XXX
resolve to constant boolean values, while predicates of the form enable_if_XXX
resolve to the second type parameter R if the first parameter T passes
the test.
Example usage:
.. code-block:: cpp
template<typename TypeClass> arrow::enable_if_number<TypeClass, RETURN_TYPE> MyFunction(const TypeClass& type) { .. }
template<typename ArrayType, typename TypeClass=ArrayType::TypeClass> arrow::enable_if_number<TypeClass, RETURN_TYPE> MyFunction(const ArrayType& array) { .. }
.. doxygengroup:: type-predicates :content-only: :members: :undoc-members:
Type predicates that can be applied at runtime.
.. doxygengroup:: runtime-type-predicates :content-only: :members: :undoc-members: