byte_range support for multibyte_split/read_text

conda/recipes/libcudf/meta.yaml

@@ -137,6 +137,7 @@ test:
     - test -f $PREFIX/include/cudf/io/orc_metadata.hpp
     - test -f $PREFIX/include/cudf/io/orc.hpp
     - test -f $PREFIX/include/cudf/io/parquet.hpp
+    - test -f $PREFIX/include/cudf/io/text/byte_range_info.hpp
     - test -f $PREFIX/include/cudf/io/text/data_chunk_source_factories.hpp
     - test -f $PREFIX/include/cudf/io/text/data_chunk_source.hpp
     - test -f $PREFIX/include/cudf/io/text/detail/multistate.hpp

cpp/CMakeLists.txt

@@ -311,6 +311,7 @@ add_library(
   src/io/parquet/writer_impl.cu
   src/io/statistics/orc_column_statistics.cu
   src/io/statistics/parquet_column_statistics.cu
+  src/io/text/byte_range_info.cpp
   src/io/text/multibyte_split.cu
   src/io/utilities/column_buffer.cpp
   src/io/utilities/config_utils.cpp

cpp/include/cudf/io/text/byte_range_info.hpp

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2022, NVIDIA CORPORATION.
+ *
+ * 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 implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <cstdint>
+#include <vector>
+
+namespace cudf {
+namespace io {
+namespace text {
+
+/**
+ * @brief stores offset and size used to indicate a byte range
+ */
+struct byte_range_info {
+ public:
+  int64_t offset;
+  int64_t size;
+
+  byte_range_info() : offset(0), size(0) {}
+  byte_range_info(int64_t offset, int64_t size) : offset(offset), size(size) {}
+
+  static byte_range_info whole_source();
+  /**
+   * @brief Create a collection of consecutive ranges between [0, total_bytes).
+   *
+   * Each range wil be the same size except if `total_bytes` is not evenly divisible by
+   * `range_count`, in which case the last range size will be the remainder.
+   *
+   * @param total_bytes total number of bytes in all ranges
+   * @param range_count total number of ranges in which to divide bytes
+   * @return Vector of range objects
+   */
+  static std::vector<byte_range_info> create_consecutive(int64_t total_bytes, int64_t range_count);
+};
+
+}  // namespace text
+}  // namespace io
+}  // namespace cudf

cpp/include/cudf/io/text/data_chunk_source.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, NVIDIA CORPORATION.
+ * Copyright (c) 2022, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -36,6 +36,7 @@ namespace text {
  */
 class device_data_chunk {
  public:
+  virtual ~device_data_chunk()                     = default;
   [[nodiscard]] virtual char const* data() const   = 0;
   [[nodiscard]] virtual std::size_t size() const   = 0;
   virtual operator device_span<char const>() const = 0;
@@ -52,6 +53,9 @@ class device_data_chunk {
  */
 class data_chunk_reader {
  public:
+  virtual ~data_chunk_reader()              = default;
+  virtual void skip_bytes(std::size_t size) = 0;
+
   /**
    * @brief Get the next chunk of bytes from the data source
    *
@@ -76,6 +80,7 @@ class data_chunk_reader {
  */
 class data_chunk_source {
  public:
+  virtual ~data_chunk_source()                                                   = default;
   [[nodiscard]] virtual std::unique_ptr<data_chunk_reader> create_reader() const = 0;
 };
 

cpp/include/cudf/io/text/data_chunk_source_factories.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, NVIDIA CORPORATION.
+ * Copyright (c) 2022, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -89,6 +89,8 @@ class istream_data_chunk_reader : public data_chunk_reader {
     }
   }
 
+  void skip_bytes(std::size_t size) override { _datastream->ignore(size); };
+
   std::unique_ptr<device_data_chunk> get_next_chunk(std::size_t read_size,
                                                     rmm::cuda_stream_view stream) override
   {
@@ -143,6 +145,12 @@ class device_span_data_chunk_reader : public data_chunk_reader {
  public:
   device_span_data_chunk_reader(device_span<char const> data) : _data(data) {}
 
+  void skip_bytes(std::size_t read_size) override
+  {
+    if (read_size > _data.size() - _position) { read_size = _data.size() - _position; }
+    _position += read_size;
+  };
+
   std::unique_ptr<device_data_chunk> get_next_chunk(std::size_t read_size,
                                                     rmm::cuda_stream_view stream) override
   {

cpp/include/cudf/io/text/detail/trie.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, NVIDIA CORPORATION.
+ * Copyright (c) 2022, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -89,20 +89,6 @@ struct trie_device_view {
    */
   constexpr uint8_t get_match_length(uint16_t idx) { return _nodes[idx].match_length; }
 
-  /**
-   * @brief returns the longest matching state of any state in the multistate.
-   */
-  template <uint32_t N>
-  constexpr uint8_t get_match_length(multistate const& states)
-  {
-    int8_t val = 0;
-    for (uint8_t i = 0; i < states.size(); i++) {
-      auto match_length = get_match_length(states.get_tail(i));
-      if (match_length > val) { val = match_length; }
-    }
-    return val;
-  }
-
  private:
   constexpr void transition_enqueue_all(  //
     char c,

cpp/include/cudf/io/text/multibyte_split.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, NVIDIA CORPORATION.
+ * Copyright (c) 2022, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,6 +17,7 @@
 #pragma once
 
 #include <cudf/column/column.hpp>
+#include <cudf/io/text/byte_range_info.hpp>
 #include <cudf/io/text/data_chunk_source.hpp>
 
 #include <rmm/mr/device/device_memory_resource.hpp>
@@ -27,10 +28,37 @@ namespace cudf {
 namespace io {
 namespace text {
 
+/**
+ * @brief Splits the source text in to a strings column using a multiple byte delimiter.
+ *
+ * providing a byte range allows multibyte_split to read a whole file, but only return the offsets
+ * of delimiters which begin within the range. If thinking in terms of "records", where each
+ * delimiter dictates the end of a record, we return all records which begin within the byte range
+ * provided, and ignore all other records, including any record which may end (but not begin)
+ * within the range, and including any record which may begin in the range but end outside of the
+ * range.
+ *
+ * @param source The source string
+ * @param delimiter UTF-8 encoded string for which to find offsets in the source
+ * @param byte_range range in which to consider offsets relevant
+ * @param mr Memory resource to use for the device memory allocation
+ * @return The strings found by splitting the source by the delimiter within the relevant byte
+ * range.
+ */
 std::unique_ptr<cudf::column> multibyte_split(
   data_chunk_source const& source,
   std::string const& delimiter,
-  rmm::mr::device_memory_resource* mr = rmm::mr::get_current_device_resource());
+  std::optional<byte_range_info> byte_range = std::nullopt,
+  rmm::mr::device_memory_resource* mr       = rmm::mr::get_current_device_resource());
+
+std::unique_ptr<cudf::column> multibyte_split(data_chunk_source const& source,
+                                              std::string const& delimiter,
+                                              byte_range_info byte_range,
+                                              rmm::mr::device_memory_resource* mr);
+
+std::unique_ptr<cudf::column> multibyte_split(data_chunk_source const& source,
+                                              std::string const& delimiter,
+                                              rmm::mr::device_memory_resource* mr);
 
 }  // namespace text
 }  // namespace io

cpp/src/io/text/byte_range_info.cpp

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2022, NVIDIA CORPORATION.
+ *
+ * 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 implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <cudf/detail/utilities/integer_utils.hpp>
+#include <cudf/io/text/byte_range_info.hpp>
+
+#include <limits>
+
+namespace cudf {
+namespace io {
+namespace text {
+
+byte_range_info byte_range_info::whole_source() { return {0, std::numeric_limits<int64_t>::max()}; }
+
+std::vector<byte_range_info> byte_range_info::create_consecutive(int64_t total_bytes,
+                                                                 int64_t range_count)
+{
+  auto range_size = util::div_rounding_up_safe(total_bytes, range_count);
+
+  std::vector<byte_range_info> ranges;
+
+  for (int64_t i = 0; i < range_count; i++) {
+    auto offset = i * range_size;
+    auto size   = std::min(range_size, total_bytes - offset);
+    ranges.push_back(byte_range_info{offset, size});
+  }
+
+  return ranges;
+}
+
+}  // namespace text
+}  // namespace io
+}  // namespace cudf