Revert removal of skip_rows / num_rows options from the Parquet reader.

cpp/include/cudf/io/parquet.hpp

@@ -57,6 +57,10 @@ class parquet_reader_options {
 
   // List of individual row groups to read (ignored if empty)
   std::vector<std::vector<size_type>> _row_groups;
+  // Number of rows to skip from the start
+  size_type _skip_rows = 0;
+  // Number of rows to read; -1 is all
+  size_type _num_rows = -1;
 
   // Whether to store string data as categorical type
   bool _convert_strings_to_categories = false;
@@ -127,6 +131,20 @@ class parquet_reader_options {
     return _reader_column_schema;
   }
 
+  /**
+   * @brief Returns number of rows to skip from the start.
+   *
+   * @return Number of rows to skip from the start
+   */
+  [[nodiscard]] size_type get_skip_rows() const { return _skip_rows; }
+
+  /**
+   * @brief Returns number of rows to read.
+   *
+   * @return Number of rows to read
+   */
+  [[nodiscard]] size_type get_num_rows() const { return _num_rows; }
+
   /**
    * @brief Returns names of column to be read, if set.
    *
@@ -162,6 +180,10 @@ class parquet_reader_options {
    */
   void set_row_groups(std::vector<std::vector<size_type>> row_groups)
   {
+    if ((!row_groups.empty()) and ((_skip_rows != 0) or (_num_rows != -1))) {
+      CUDF_FAIL("row_groups can't be set along with skip_rows and num_rows");
+    }
+
     _row_groups = std::move(row_groups);
   }
 
@@ -190,6 +212,34 @@ class parquet_reader_options {
     _reader_column_schema = std::move(val);
   }
 
+  /**
+   * @brief Sets number of rows to skip.
+   *
+   * @param val Number of rows to skip from start
+   */
+  void set_skip_rows(size_type val)
+  {
+    if ((val != 0) and (!_row_groups.empty())) {
+      CUDF_FAIL("skip_rows can't be set along with a non-empty row_groups");
+    }
+
+    _skip_rows = val;
+  }
+
+  /**
+   * @brief Sets number of rows to read.
+   *
+   * @param val Number of rows to read after skip
+   */
+  void set_num_rows(size_type val)
+  {
+    if ((val != -1) and (!_row_groups.empty())) {
+      CUDF_FAIL("num_rows can't be set along with a non-empty row_groups");
+    }
+
+    _num_rows = val;
+  }
+
   /**
    * @brief Sets timestamp_type used to cast timestamp columns.
    *
@@ -279,6 +329,30 @@ class parquet_reader_options_builder {
     return *this;
   }
 
+  /**
+   * @brief Sets number of rows to skip.
+   *
+   * @param val Number of rows to skip from start
+   * @return this for chaining
+   */
+  parquet_reader_options_builder& skip_rows(size_type val)
+  {
+    options.set_skip_rows(val);
+    return *this;
+  }
+
+  /**
+   * @brief Sets number of rows to read.
+   *
+   * @param val Number of rows to read after skip
+   * @return this for chaining
+   */
+  parquet_reader_options_builder& num_rows(size_type val)
+  {
+    options.set_num_rows(val);
+    return *this;
+  }
+
   /**
    * @brief timestamp_type used to cast timestamp columns.
    *