Implemented variable_size_binary_layout (#32)

Implemented variable_size_binary_layout

CMakeLists.txt

@@ -57,6 +57,7 @@ set(SPARROW_HEADERS
  ${SPARROW_INCLUDE_DIR}/sparrow/iterator.hpp
  ${SPARROW_INCLUDE_DIR}/sparrow/mp_utils.hpp
  ${SPARROW_INCLUDE_DIR}/sparrow/sparrow_version.hpp
+ ${SPARROW_INCLUDE_DIR}/sparrow/variable_size_binary_layout.hpp
 )
 
 add_library(sparrow INTERFACE)

include/sparrow/array_data.hpp

@@ -116,11 +116,11 @@ namespace sparrow
  using base_type = reference_proxy_base<self_type>;
  using layout_type = L;
  using value_type = typename L::inner_value_type;
- using reference = typename L::inner_const_reference;
- using bitmap_reference = typename L::bitmap_const_reference;
+ using const_reference = typename L::inner_const_reference;
+ using bitmap_const_reference = typename L::bitmap_const_reference;
  using size_type = typename L::size_type;
 
- const_reference_proxy(reference val_ref, bitmap_reference bit_ref);
+ const_reference_proxy(const_reference val_ref, bitmap_const_reference bit_ref);
  ~const_reference_proxy() = default;
 
  const_reference_proxy(const self_type&) = default;
@@ -129,12 +129,12 @@ namespace sparrow
  bool has_value() const;
  explicit operator bool() const;
 
- const value_type& value() const;
+ const_reference value() const;
 
  private:
 
- reference m_val_ref;
- bitmap_reference m_bit_ref;
+ const_reference m_val_ref;
+ bitmap_const_reference m_bit_ref;
  };
 
  /**
@@ -259,7 +259,7 @@ namespace sparrow
  ****************************************/
 
  template <class L>
- const_reference_proxy<L>::const_reference_proxy(reference val_ref, bitmap_reference bit_ref)
+ const_reference_proxy<L>::const_reference_proxy(const_reference val_ref, bitmap_const_reference bit_ref)
  : m_val_ref(val_ref)
  , m_bit_ref(bit_ref)
  {
@@ -278,7 +278,7 @@ namespace sparrow
  }
 
  template <class L>
- auto const_reference_proxy<L>::value() const -> const value_type&
+ auto const_reference_proxy<L>::value() const -> const_reference
  {
  assert(has_value());
  return m_val_ref;

include/sparrow/variable_size_binary_layout.hpp

@@ -0,0 +1,340 @@
+// Copyright 2024 Man Group Operations Limited
+//
+// Licensed 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 mplied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <ranges>
+#include "sparrow/array_data.hpp"
+#include "sparrow/iterator.hpp"
+
+namespace sparrow
+{
+ namespace impl
+ {
+ template <class C, bool is_const>
+ struct get_inner_reference
+ : std::conditional<
+ is_const,
+ typename C::inner_const_reference,
+ typename C::inner_reference
+ >
+ {
+ };
+
+ template <class C, bool is_const>
+ using get_inner_reference_t = typename get_inner_reference<C, is_const>::type;
+ }
+
+ template <class T>
+ concept layout_offset = std::same_as<T, std::int32_t> || std::same_as<T, std::int64_t>;
+
+ /**
+ * @class vs_binary_value_iterator
+ *
+ * @brief Iterator over the data values of a variable size binary
+ * layout.
+ *
+ * @tparam L the layout type
+ * @tparam is_const a boolean flag specifying whether this iterator is const.
+ */
+ template <class L, bool is_const>
+ class vs_binary_value_iterator : public iterator_base
+ <
+ vs_binary_value_iterator<L, is_const>,
+ mpl::constify_t<typename L::inner_value_type, is_const>,
+ std::contiguous_iterator_tag,
+ impl::get_inner_reference_t<L, is_const>
+ >
+ {
+ public:
+
+ using self_type = vs_binary_value_iterator<L, is_const>;
+ using base_type = iterator_base
+ <
+ self_type,
+ mpl::constify_t<typename L::inner_value_type, is_const>,
+ std::contiguous_iterator_tag,
+ impl::get_inner_reference_t<L, is_const>
+ >;
+ using reference = typename base_type::reference;
+ using difference_type = typename base_type::difference_type;
+
+ using offset_iterator = std::conditional_t<
+ is_const, typename L::const_offset_iterator, typename L::offset_iterator
+ >;
+ using data_iterator = std::conditional_t<
+ is_const, typename L::const_data_iterator, typename L::data_iterator
+ >;
+
+ vs_binary_value_iterator() noexcept = default;
+ vs_binary_value_iterator(
+ offset_iterator offset_it,
+ data_iterator data_begin
+ );
+
+ private:
+
+ reference dereference() const;
+ void increment();
+ void decrement();
+ void advance(difference_type n);
+ difference_type distance_to(const self_type& rhs) const;
+ bool equal(const self_type& rhs) const;
+ bool less_than(const self_type& rhs) const;
+
+ offset_iterator m_offset_it;
+ data_iterator m_data_begin;
+
+ friend class iterator_access;
+ };
+
+ /*
+ * @class variable_size_binary_layout
+ *
+ * @brief Layout for arrays containing values consisting of a variable number of bytes.
+ *
+ * This layout is used to retrieve data in an array of values of a variable number of bytes
+ * (typically string objects). Values are stored contiguously in a data buffer (for instance
+ * a buffer of char if values are strings), a single value is retrieved via an additional
+ * offset buffer, where each element is the beginning of the corresponding value in the data
+ * buffer.
+ *
+ * Example:
+ *
+ * Let's consider the array of string ['please', 'allow', 'me', 'to', 'introduce', 'myself'].
+ * The internal buffers will be:
+ * - offset: [0, 6, 11, 13, 15, 24, 30]
+ * - data: ['p','l','e','a','s','e','a','l','l','o','w','m','e','t','o','i','n','t','r','o','d','u','c','e','m','y','s','e','l','f']
+ * 
+ * @tparam T the type of the data stored in the data buffer, not its byte representation.
+ * @tparam R the reference type to the data. This type is different from the reference type of the layout,
+ * which behaves like std::optional<R>.
+ * @tparam CR the const reference type to the data. This type is different from the const reference of the layout,
+ * which behaves like std::optional<CR>.
+ * @tparam OT type of the offset values. Must be std::int64_t or std::int32_t.
+ */
+ template <class T, class R, class CR, layout_offset OT = std::int64_t>
+ class variable_size_binary_layout
+ {
+ public:
+
+ using self_type = variable_size_binary_layout<T, R, CR, OT>;
+ using inner_value_type = T;
+ using inner_reference = R;
+ using inner_const_reference = CR;
+ using bitmap_type = array_data::bitmap_type;
+ using bitmap_const_reference = typename bitmap_type::const_reference;
+ using value_type = std::optional<inner_value_type>;
+ using const_reference = const_reference_proxy<self_type>;
+ using size_type = std::size_t;
+
+ /**
+ * These types have to be public to be accessible when
+ * instantiating const_value_iterator for checking the
+ * requirements of subrange.
+ */
+ using data_type = typename T::value_type;
+ using offset_iterator = OT*;
+ using const_offset_iterator = const OT*;
+ using data_iterator = data_type*;
+ using const_data_iterator = const data_type*;
+
+ using const_bitmap_iterator = array_data::bitmap_type::const_iterator;
+ using const_value_iterator = vs_binary_value_iterator<self_type, true>;
+
+ using const_bitmap_range = std::ranges::subrange<const_bitmap_iterator>;
+ using const_value_range = std::ranges::subrange<const_value_iterator>;
+
+ explicit variable_size_binary_layout(array_data data);
+
+ size_type size() const;
+ const_reference operator[](size_type i) const;
+
+ const_bitmap_range bitmap() const;
+ const_value_range values() const;
+
+ private:
+
+ const_value_iterator value_cbegin() const;
+ const_value_iterator value_cend() const;
+
+ const_bitmap_iterator bitmap_cbegin() const;
+ const_bitmap_iterator bitmap_cend() const;
+
+ bool has_value(size_type i) const;
+ inner_const_reference value(size_type i) const;
+
+ const_offset_iterator offset(size_type i) const;
+ const_offset_iterator offset_end() const;
+ const_data_iterator data(size_type i) const;
+
+ array_data m_data;
+
+ friend class const_reference_proxy<self_type>;
+ friend class vs_binary_value_iterator<self_type, true>;
+ };
+
+ /*******************************************
+ * vs_binary_value_iterator implementation *
+ *******************************************/
+
+ template <class L, bool is_const>
+ vs_binary_value_iterator<L, is_const>::vs_binary_value_iterator(
+ offset_iterator offset_it,
+ data_iterator data_begin
+ )
+ : m_offset_it(offset_it)
+ , m_data_begin(data_begin)
+ {
+ }
+
+ template <class L, bool is_const>
+ auto vs_binary_value_iterator<L, is_const>::dereference() const -> reference
+ {
+ return reference(m_data_begin + *m_offset_it, m_data_begin + *(m_offset_it + 1));
+ }
+
+ template <class L, bool is_const>
+ void vs_binary_value_iterator<L, is_const>::increment()
+ {
+ ++m_offset_it;
+ }
+
+ template <class L, bool is_const>
+ void vs_binary_value_iterator<L, is_const>::decrement()
+ {
+ --m_offset_it;
+ }
+
+ template <class L, bool is_const>
+ void vs_binary_value_iterator<L, is_const>::advance(difference_type n)
+ {
+ m_offset_it += n;
+ }
+
+ template <class L, bool is_const>
+ auto vs_binary_value_iterator<L, is_const>::distance_to(const self_type& rhs) const -> difference_type
+ {
+ return rhs.m_offset_it - m_offset_it;
+ }
+
+ template <class L, bool is_const>
+ bool vs_binary_value_iterator<L, is_const>::equal(const self_type& rhs) const
+ {
+ return m_offset_it == rhs.m_offset_it;
+ }
+
+ template <class L, bool is_const>
+ bool vs_binary_value_iterator<L, is_const>::less_than(const self_type& rhs) const
+ {
+ return m_offset_it < rhs.m_offset_it;
+ }
+
+ /**********************************************
+ * variable_size_binary_layout implementation *
+ **********************************************/
+
+ template <class T, class R, class CR, layout_offset OT>
+ variable_size_binary_layout<T, R, CR, OT>::variable_size_binary_layout(array_data data)
+ : m_data(std::move(data))
+ {
+ assert(m_data.buffers.size() == 2u);
+ //TODO: templatize back and front in buffer and uncomment the following line
+ //assert(m_data.buffers[0].size() == 0u || m_data.buffers[0].back() == m_data.buffers[1].size());
+ }
+
+ template <class T, class R, class CR, layout_offset OT>
+ auto variable_size_binary_layout<T, R, CR, OT>::size() const -> size_type
+ {
+ assert(m_data.offset <= m_data.length);
+ return static_cast<size_type>(m_data.length - m_data.offset);
+ }
+
+ template <class T, class R, class CR, layout_offset OT>
+ auto variable_size_binary_layout<T, R, CR, OT>::operator[](size_type i) const -> const_reference
+ {
+ assert(i < size());
+ return const_reference(value(i), has_value(i));
+ }
+
+ template <class T, class R, class CR, layout_offset OT>
+ auto variable_size_binary_layout<T, R, CR, OT>::bitmap() const -> const_bitmap_range
+ {
+ return std::ranges::subrange(bitmap_cbegin(), bitmap_cend());
+ }
+
+ template <class T, class R, class CR, layout_offset OT>
+ auto variable_size_binary_layout<T, R, CR, OT>::values() const -> const_value_range
+ {
+ return std::ranges::subrange(value_cbegin(), value_cend());
+ }
+
+ template <class T, class R, class CR, layout_offset OT>
+ auto variable_size_binary_layout<T, R, CR, OT>::bitmap_cbegin() const -> const_bitmap_iterator
+ {
+ return m_data.bitmap.cbegin() + m_data.offset;
+ }
+
+ template <class T, class R, class CR, layout_offset OT>
+ auto variable_size_binary_layout<T, R, CR, OT>::bitmap_cend() const -> const_bitmap_iterator
+ {
+ return m_data.bitmap.cend();
+ }
+
+ template <class T, class R, class CR, layout_offset OT>
+ auto variable_size_binary_layout<T, R, CR, OT>::value_cbegin() const -> const_value_iterator
+ {
+ return const_value_iterator(offset(0u), data(0u));
+ }
+
+ template <class T, class R, class CR, layout_offset OT>
+ auto variable_size_binary_layout<T, R, CR, OT>::value_cend() const -> const_value_iterator
+ {
+ return const_value_iterator(offset_end(), data(0u));
+ }
+
+ template <class T, class R, class CR, layout_offset OT>
+ auto variable_size_binary_layout<T, R, CR, OT>::has_value(size_type i) const -> bool
+ {
+ return m_data.bitmap.test(i + m_data.offset);
+ }
+
+ template <class T, class R, class CR, layout_offset OT>
+ auto variable_size_binary_layout<T, R, CR, OT>::value(size_type i) const -> inner_const_reference
+ {
+ return inner_const_reference(data(*offset(i)), data(*offset(i+1)));
+ }
+
+ template <class T, class R, class CR, layout_offset OT>
+ auto variable_size_binary_layout<T, R, CR, OT>::offset(size_type i) const -> const_offset_iterator
+ {
+ assert(!m_data.buffers.empty());
+ return m_data.buffers[0].template data<OT>() + m_data.offset + i;
+ }
+
+ template <class T, class R, class CR, layout_offset OT>
+ auto variable_size_binary_layout<T, R, CR, OT>::offset_end() const -> const_offset_iterator
+ {
+ assert(!m_data.buffers.empty());
+ return m_data.buffers[0].template data<OT>() + m_data.length;
+ }
+
+ template <class T, class R, class CR, layout_offset OT>
+ auto variable_size_binary_layout<T, R, CR, OT>::data(size_type i) const -> const_data_iterator
+ {
+ assert(!m_data.buffers.empty());
+ return m_data.buffers[1].template data<data_type>() + i;
+ }
+}
+