Remove strings_count parameter from cudf::strings::detail::create_cha…

…rs_child_column (#8576)

Closes #8559 

The `strings_count` parameter was necessary in a previous version of the `cudf::strings::detail::create_chars_child_column` but has become obsolete. This PR removes the parameter and fixes up the calls to the utility.

Authors:
  - David Wendt (https://github.com/davidwendt)

Approvers:
  - Mark Harris (https://github.com/harrism)
  - Karthikeyan (https://github.com/karthikeyann)
  - Nghia Truong (https://github.com/ttnghia)

URL: #8576

cpp/include/cudf/strings/detail/copy_if_else.cuh

@@ -93,7 +93,7 @@ std::unique_ptr<cudf::column> copy_if_else(
   // build chars column
   auto const bytes =
     cudf::detail::get_value<int32_t>(offsets_column->view(), strings_count, stream);
-  auto chars_column = create_chars_child_column(strings_count, bytes, stream, mr);
+  auto chars_column = create_chars_child_column(bytes, stream, mr);
   auto d_chars      = chars_column->mutable_view().template data<char>();
   // fill in chars
   thrust::for_each_n(

cpp/include/cudf/strings/detail/copy_range.cuh

@@ -183,8 +183,7 @@ std::unique_ptr<column> copy_range(
       thrust::device_pointer_cast(p_offsets_column->view().template data<size_type>());
     auto const chars_bytes =
       cudf::detail::get_value<int32_t>(p_offsets_column->view(), target.size(), stream);
-    auto p_chars_column =
-      strings::detail::create_chars_child_column(target.size(), chars_bytes, stream, mr);
+    auto p_chars_column = strings::detail::create_chars_child_column(chars_bytes, stream, mr);
 
     // copy to the chars column
 

cpp/include/cudf/strings/detail/gather.cuh

@@ -229,7 +229,7 @@ std::unique_ptr<cudf::column> gather_chars(StringIterator strings_begin,
   auto const output_count = std::distance(map_begin, map_end);
   if (output_count == 0) return make_empty_column(data_type{type_id::INT8});
 
-  auto chars_column  = create_chars_child_column(output_count, chars_bytes, stream, mr);
+  auto chars_column  = create_chars_child_column(chars_bytes, stream, mr);
   auto const d_chars = chars_column->mutable_view().template data<char>();
 
   constexpr int warps_per_threadblock = 4;

cpp/include/cudf/strings/detail/merge.cuh

@@ -83,7 +83,7 @@ std::unique_ptr<column> merge(strings_column_view const& lhs,
   // create the chars column
   auto const bytes =
     cudf::detail::get_value<int32_t>(offsets_column->view(), strings_count, stream);
-  auto chars_column = strings::detail::create_chars_child_column(strings_count, bytes, stream, mr);
+  auto chars_column = strings::detail::create_chars_child_column(bytes, stream, mr);
   // merge the strings
   auto d_chars = chars_column->mutable_view().template data<char>();
   thrust::for_each_n(rmm::exec_policy(stream),

cpp/include/cudf/strings/detail/strings_column_factories.cuh

@@ -111,10 +111,9 @@ std::unique_ptr<column> make_strings_column(IndexPairIterator begin,
                           mr);
     } else {
       // this approach is 2-3x faster for a large number of smaller string lengths
-      auto chars_column =
-        strings::detail::create_chars_child_column(strings_count, bytes, stream, mr);
-      auto d_chars    = chars_column->mutable_view().template data<char>();
-      auto copy_chars = [d_chars] __device__(auto item) {
+      auto chars_column = create_chars_child_column(bytes, stream, mr);
+      auto d_chars      = chars_column->mutable_view().template data<char>();
+      auto copy_chars   = [d_chars] __device__(auto item) {
         string_index_pair const str = thrust::get<0>(item);
         size_type const offset      = thrust::get<1>(item);
         if (str.first != nullptr) memcpy(d_chars + offset, str.first, str.second);
@@ -182,7 +181,7 @@ std::unique_ptr<column> make_strings_column(CharIterator chars_begin,
                     [] __device__(auto offset) { return static_cast<int32_t>(offset); });
 
   // build chars column
-  auto chars_column = strings::detail::create_chars_child_column(strings_count, bytes, stream, mr);
+  auto chars_column = strings::detail::create_chars_child_column(bytes, stream, mr);
   auto chars_view   = chars_column->mutable_view();
   thrust::copy(rmm::exec_policy(stream), chars_begin, chars_end, chars_view.data<char>());
 

cpp/include/cudf/strings/detail/utilities.cuh

@@ -166,8 +166,7 @@ auto make_strings_children(
 
   // Now build the chars column
   auto const bytes = cudf::detail::get_value<int32_t>(offsets_view, strings_count, stream);
-  std::unique_ptr<column> chars_column =
-    create_chars_child_column(strings_count, bytes, stream, mr);
+  std::unique_ptr<column> chars_column = create_chars_child_column(bytes, stream, mr);
 
   // Execute the function fn again to fill the chars column.
   // Note that if the output chars column has zero size, the function fn should not be called to
@@ -261,7 +260,7 @@ make_strings_children_with_null_mask(
 
   // Now build the chars column
   auto const bytes  = cudf::detail::get_value<int32_t>(offsets_view, strings_count, stream);
-  auto chars_column = create_chars_child_column(strings_count, bytes, stream, mr);
+  auto chars_column = create_chars_child_column(bytes, stream, mr);
 
   // Execute the function fn again to fill the chars column.
   // Note that if the output chars column has zero size, the function fn should not be called to

cpp/include/cudf/strings/detail/utilities.hpp

@@ -27,16 +27,15 @@ namespace strings {
 namespace detail {
 /**
  * @brief Create a chars column to be a child of a strings column.
+ *
  * This will return the properly sized column to be filled in by the caller.
  *
- * @param strings_count Number of strings in the column.
  * @param bytes Number of bytes for the chars column.
  * @param stream CUDA stream used for device memory operations and kernel launches.
  * @param mr Device memory resource used to allocate the returned column's device memory.
  * @return The chars child column for a strings column.
  */
 std::unique_ptr<column> create_chars_child_column(
-  size_type strings_count,
   size_type bytes,
   rmm::cuda_stream_view stream        = rmm::cuda_stream_default,
   rmm::mr::device_memory_resource* mr = rmm::mr::get_current_device_resource());

cpp/src/hash/md5_hash.cu

@@ -64,10 +64,9 @@ std::unique_ptr<column> md5_hash(table_view const& input,
   auto offsets_column =
     cudf::strings::detail::make_offsets_child_column(begin, begin + input.num_rows(), stream, mr);
 
-  auto chars_column =
-    strings::detail::create_chars_child_column(input.num_rows(), input.num_rows() * 32, stream, mr);
-  auto chars_view = chars_column->mutable_view();
-  auto d_chars    = chars_view.data<char>();
+  auto chars_column = strings::detail::create_chars_child_column(input.num_rows() * 32, stream, mr);
+  auto chars_view   = chars_column->mutable_view();
+  auto d_chars      = chars_view.data<char>();
 
   rmm::device_buffer null_mask{0, stream, mr};
 

cpp/src/io/csv/durations.cu

@@ -190,10 +190,9 @@ struct dispatch_from_durations_fn {
     // build chars column
     auto const chars_bytes =
       cudf::detail::get_value<int32_t>(offsets_column->view(), strings_count, stream);
-    auto chars_column =
-      strings::detail::create_chars_child_column(strings_count, chars_bytes, stream, mr);
-    auto chars_view = chars_column->mutable_view();
-    auto d_chars    = chars_view.template data<char>();
+    auto chars_column = strings::detail::create_chars_child_column(chars_bytes, stream, mr);
+    auto chars_view   = chars_column->mutable_view();
+    auto d_chars      = chars_view.template data<char>();
 
     thrust::for_each_n(rmm::exec_policy(stream),
                        thrust::make_counting_iterator<size_type>(0),

cpp/src/replace/clamp.cu

@@ -67,8 +67,7 @@ std::pair<std::unique_ptr<column>, std::unique_ptr<column>> form_offsets_and_cha
   // build chars column
   auto const bytes =
     cudf::detail::get_value<int32_t>(offsets_column->view(), strings_count, stream);
-  auto chars_column =
-    cudf::strings::detail::create_chars_child_column(strings_count, bytes, stream, mr);
+  auto chars_column = cudf::strings::detail::create_chars_child_column(bytes, stream, mr);
 
   return std::make_pair(std::move(offsets_column), std::move(chars_column));
 }

cpp/src/replace/nulls.cu

@@ -254,7 +254,7 @@ std::unique_ptr<cudf::column> replace_nulls_column_kernel_forwarder::operator()<
 
   // Allocate chars array and output null mask
   std::unique_ptr<cudf::column> output_chars =
-    cudf::strings::detail::create_chars_child_column(input.size(), bytes, stream, mr);
+    cudf::strings::detail::create_chars_child_column(bytes, stream, mr);
 
   auto output_chars_view = output_chars->mutable_view();
 

cpp/src/replace/replace.cu

@@ -419,7 +419,7 @@ std::unique_ptr<cudf::column> replace_kernel_forwarder::operator()<cudf::string_
   // Allocate chars array and output null mask
   cudf::size_type null_count = input_col.size() - valid_counter.value(stream);
   std::unique_ptr<cudf::column> output_chars =
-    cudf::strings::detail::create_chars_child_column(input_col.size(), bytes, stream, mr);
+    cudf::strings::detail::create_chars_child_column(bytes, stream, mr);
 
   auto output_chars_view = output_chars->mutable_view();
   auto device_chars      = cudf::mutable_column_device_view::create(output_chars_view);

cpp/src/reshape/interleave_columns.cu

@@ -104,7 +104,7 @@ struct interleave_columns_functor {
     // Create the chars column
     auto const bytes =
       cudf::detail::get_value<int32_t>(offsets_column->view(), num_strings, stream);
-    auto chars_column = strings::detail::create_chars_child_column(num_strings, bytes, stream, mr);
+    auto chars_column = strings::detail::create_chars_child_column(bytes, stream, mr);
     // Fill the chars column
     auto d_results_chars = chars_column->mutable_view().data<char>();
     thrust::for_each_n(

cpp/src/strings/combine/join.cu

@@ -97,7 +97,7 @@ std::unique_ptr<column> join_strings(strings_column_view const& strings,
   auto null_mask = null_count
                      ? cudf::detail::create_null_mask(1, cudf::mask_state::ALL_NULL, stream, mr)
                      : rmm::device_buffer{0, stream, mr};
-  auto chars_column = detail::create_chars_child_column(strings_count, bytes, stream, mr);
+  auto chars_column = create_chars_child_column(bytes, stream, mr);
   auto d_chars      = chars_column->mutable_view().data<char>();
   thrust::for_each_n(
     rmm::exec_policy(stream),

cpp/src/strings/convert/convert_booleans.cu

@@ -125,7 +125,7 @@ std::unique_ptr<column> from_booleans(column_view const& booleans,
   // build chars column
   auto const bytes =
     cudf::detail::get_value<int32_t>(offsets_column->view(), strings_count, stream);
-  auto chars_column = create_chars_child_column(strings_count, bytes, stream, mr);
+  auto chars_column = create_chars_child_column(bytes, stream, mr);
   auto d_chars      = chars_column->mutable_view().data<char>();
   thrust::for_each_n(rmm::exec_policy(stream),
                      thrust::make_counting_iterator<size_type>(0),

cpp/src/strings/convert/convert_datetime.cu

@@ -958,7 +958,7 @@ std::unique_ptr<column> from_timestamps(column_view const& timestamps,
   // build chars column
   auto const bytes =
     cudf::detail::get_value<int32_t>(offsets_column->view(), strings_count, stream);
-  auto chars_column = create_chars_child_column(strings_count, bytes, stream, mr);
+  auto chars_column = create_chars_child_column(bytes, stream, mr);
   auto d_chars      = chars_column->mutable_view().template data<char>();
   // fill in chars column with timestamps
   // dispatcher is called to handle the different timestamp types

cpp/src/strings/convert/convert_durations.cu

@@ -427,7 +427,7 @@ struct dispatch_from_durations_fn {
     // build chars column
     auto const chars_bytes =
       cudf::detail::get_value<int32_t>(offsets_column->view(), strings_count, stream);
-    auto chars_column = detail::create_chars_child_column(strings_count, chars_bytes, stream, mr);
+    auto chars_column = detail::create_chars_child_column(chars_bytes, stream, mr);
     auto d_chars      = chars_column->mutable_view().template data<char>();
 
     thrust::for_each_n(rmm::exec_policy(stream),

cpp/src/strings/convert/convert_fixed_point.cu

@@ -396,7 +396,7 @@ struct dispatch_from_fixed_point_fn {
     // build chars column
     auto const bytes =
       cudf::detail::get_value<int32_t>(offsets_column->view(), input.size(), stream);
-    auto chars_column = detail::create_chars_child_column(input.size(), bytes, stream, mr);
+    auto chars_column = detail::create_chars_child_column(bytes, stream, mr);
     auto d_chars      = chars_column->mutable_view().template data<char>();
     thrust::for_each_n(rmm::exec_policy(stream),
                        thrust::make_counting_iterator<size_type>(0),

cpp/src/strings/convert/convert_floats.cu

@@ -492,7 +492,7 @@ struct dispatch_from_floats_fn {
 
     // build chars column
     auto const bytes  = cudf::detail::get_value<int32_t>(offsets_view, strings_count, stream);
-    auto chars_column = detail::create_chars_child_column(strings_count, bytes, stream, mr);
+    auto chars_column = detail::create_chars_child_column(bytes, stream, mr);
     auto chars_view   = chars_column->mutable_view();
     auto d_chars      = chars_view.template data<char>();
     thrust::for_each_n(rmm::exec_policy(stream),

cpp/src/strings/convert/convert_integers.cu

@@ -350,7 +350,7 @@ struct dispatch_from_integers_fn {
 
     // build chars column
     auto const bytes  = cudf::detail::get_value<int32_t>(offsets_view, strings_count, stream);
-    auto chars_column = detail::create_chars_child_column(strings_count, bytes, stream, mr);
+    auto chars_column = detail::create_chars_child_column(bytes, stream, mr);
     auto chars_view   = chars_column->mutable_view();
     auto d_chars      = chars_view.template data<char>();
     thrust::for_each_n(rmm::exec_policy(stream),

cpp/src/strings/convert/convert_ipv4.cu

@@ -192,7 +192,7 @@ std::unique_ptr<column> integers_to_ipv4(
   // build chars column
   auto const bytes =
     cudf::detail::get_value<int32_t>(offsets_column->view(), strings_count, stream);
-  auto chars_column = create_chars_child_column(strings_count, bytes, stream, mr);
+  auto chars_column = create_chars_child_column(bytes, stream, mr);
   auto d_chars      = chars_column->mutable_view().data<char>();
   thrust::for_each_n(rmm::exec_policy(stream),
                      thrust::make_counting_iterator<size_type>(0),

cpp/src/strings/convert/convert_urls.cu

@@ -142,7 +142,7 @@ std::unique_ptr<column> url_encode(
   auto const bytes =
     cudf::detail::get_value<int32_t>(offsets_column->view(), strings_count, stream);
   // build chars column
-  auto chars_column = create_chars_child_column(strings_count, bytes, stream, mr);
+  auto chars_column = create_chars_child_column(bytes, stream, mr);
   auto d_chars      = chars_column->mutable_view().data<char>();
   thrust::for_each_n(rmm::exec_policy(stream),
                      thrust::make_counting_iterator<size_type>(0),
@@ -392,8 +392,7 @@ std::unique_ptr<column> url_decode(
 
   // create the chars column
   auto chars_column =
-    create_chars_child_column(strings_count,
-                              chars_bytes - (esc_count * 2),  // replacing 3 bytes with 1
+    create_chars_child_column(chars_bytes - (esc_count * 2),  // replacing 3 bytes with 1
                               stream,
                               mr);
   auto d_out_chars = chars_column->mutable_view().data<char>();

cpp/src/strings/copying/concatenate.cu

@@ -22,6 +22,7 @@
 #include <cudf/detail/utilities/cuda.cuh>
 #include <cudf/detail/utilities/vector_factories.hpp>
 #include <cudf/strings/detail/concatenate.hpp>
+#include <cudf/strings/detail/utilities.hpp>
 #include <cudf/strings/strings_column_view.hpp>
 #include <cudf/table/table_device_view.cuh>
 
@@ -226,9 +227,8 @@ std::unique_ptr<column> concatenate(host_span<column_view const> columns,
     std::any_of(columns.begin(), columns.end(), [](auto const& col) { return col.has_nulls(); });
 
   // create chars column
-  auto chars_column =
-    make_numeric_column(data_type{type_id::INT8}, total_bytes, mask_state::UNALLOCATED, stream, mr);
-  auto d_new_chars = chars_column->mutable_view().data<char>();
+  auto chars_column = create_chars_child_column(total_bytes, stream, mr);
+  auto d_new_chars  = chars_column->mutable_view().data<char>();
   chars_column->set_null_count(0);
 
   // create offsets column

cpp/src/strings/filling/fill.cu

@@ -80,7 +80,7 @@ std::unique_ptr<column> fill(
   // create the chars column
   auto const bytes =
     cudf::detail::get_value<int32_t>(offsets_column->view(), strings_count, stream);
-  auto chars_column = strings::detail::create_chars_child_column(strings_count, bytes, stream, mr);
+  auto chars_column = create_chars_child_column(bytes, stream, mr);
   // fill the chars column
   auto d_chars = chars_column->mutable_view().data<char>();
   thrust::for_each_n(

cpp/src/strings/json/json_path.cu

@@ -21,6 +21,7 @@
 #include <cudf/detail/utilities/cuda.cuh>
 #include <cudf/detail/utilities/vector_factories.hpp>
 #include <cudf/scalar/scalar.hpp>
+#include <cudf/strings/detail/utilities.hpp>
 #include <cudf/strings/json.hpp>
 #include <cudf/strings/string_view.cuh>
 #include <cudf/strings/strings_column_view.hpp>
@@ -964,8 +965,7 @@ std::unique_ptr<cudf::column> get_json_object(cudf::strings_column_view const& c
     cudf::detail::get_value<offset_type>(offsets_view, col.size(), stream);
 
   // allocate output string column
-  auto chars = cudf::make_fixed_width_column(
-    data_type{type_id::INT8}, output_size, mask_state::UNALLOCATED, stream, mr);
+  auto chars = create_chars_child_column(output_size, stream, mr);
 
   // potential optimization : if we know that all outputs are valid, we could skip creating
   // the validity mask altogether

cpp/src/strings/padding.cu

@@ -82,7 +82,7 @@ std::unique_ptr<column> pad(
   // build chars column
   auto const bytes =
     cudf::detail::get_value<int32_t>(offsets_column->view(), strings_count, stream);
-  auto chars_column = strings::detail::create_chars_child_column(strings_count, bytes, stream, mr);
+  auto chars_column = strings::detail::create_chars_child_column(bytes, stream, mr);
   auto d_chars      = chars_column->mutable_view().data<char>();
 
   if (side == pad_side::LEFT) {
@@ -170,7 +170,7 @@ std::unique_ptr<column> zfill(
   // build chars column
   auto const bytes =
     cudf::detail::get_value<int32_t>(offsets_column->view(), strings_count, stream);
-  auto chars_column = strings::detail::create_chars_child_column(strings_count, bytes, stream, mr);
+  auto chars_column = strings::detail::create_chars_child_column(bytes, stream, mr);
   auto d_chars      = chars_column->mutable_view().data<char>();
 
   thrust::for_each_n(rmm::exec_policy(stream),

cpp/src/strings/repeat_strings.cu

@@ -73,7 +73,7 @@ auto generate_empty_output(strings_column_view const& input,
                            rmm::cuda_stream_view stream,
                            rmm::mr::device_memory_resource* mr)
 {
-  auto chars_column = create_chars_child_column(strings_count, 0, stream, mr);
+  auto chars_column = create_chars_child_column(0, stream, mr);
 
   auto offsets_column = make_numeric_column(
     data_type{type_to_id<offset_type>()}, strings_count + 1, mask_state::UNALLOCATED, stream, mr);

cpp/src/strings/replace/replace.cu

@@ -477,8 +477,8 @@ std::unique_ptr<column> replace_char_parallel(strings_column_view const& strings
                     offsets_update_fn);
 
   // build the characters column
-  auto chars_column = create_chars_child_column(
-    strings_count, chars_bytes + (delta_per_target * target_count), stream, mr);
+  auto chars_column =
+    create_chars_child_column(chars_bytes + (delta_per_target * target_count), stream, mr);
   auto d_out_chars = chars_column->mutable_view().data<char>();
   thrust::for_each_n(
     rmm::exec_policy(stream),
@@ -819,7 +819,7 @@ std::unique_ptr<column> replace_nulls(strings_column_view const& strings,
   // build chars column
   auto const bytes =
     cudf::detail::get_value<int32_t>(offsets_column->view(), strings_count, stream);
-  auto chars_column = strings::detail::create_chars_child_column(strings_count, bytes, stream, mr);
+  auto chars_column = create_chars_child_column(bytes, stream, mr);
   auto d_chars      = chars_column->mutable_view().data<char>();
   thrust::for_each_n(rmm::exec_policy(stream),
                      thrust::make_counting_iterator<size_type>(0),

cpp/src/strings/utilities.cu

@@ -84,8 +84,7 @@ std::unique_ptr<cudf::column> child_chars_from_string_vector(cudf::device_span<s
   auto const d_offsets = offsets.data<int32_t>();
 
   // create column
-  auto chars_column =
-    make_numeric_column(data_type{type_id::INT8}, bytes, mask_state::UNALLOCATED, stream, mr);
+  auto chars_column = create_chars_child_column(bytes, stream, mr);
   // get it's view
   auto d_chars = chars_column->mutable_view().data<char>();
   thrust::for_each_n(rmm::exec_policy(stream),
@@ -100,8 +99,7 @@ std::unique_ptr<cudf::column> child_chars_from_string_vector(cudf::device_span<s
 }
 
 //
-std::unique_ptr<column> create_chars_child_column(cudf::size_type strings_count,
-                                                  cudf::size_type total_bytes,
+std::unique_ptr<column> create_chars_child_column(cudf::size_type total_bytes,
                                                   rmm::cuda_stream_view stream,
                                                   rmm::mr::device_memory_resource* mr)
 {