read parquet files

r/R/read_parquet.R

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+#' Read parquet file from disk
+#' 
+#' @param files a vector of filenames
+#' @export
+read_parquet = function(files) {
+ tables = lapply(files, function(f) {
+ return (as_tibble(shared_ptr(`arrow::Table`, read_parquet_file(f))))
+ })
+ do.call('rbind', tables)
+}

r/src/parquetfilereader.cpp

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+// // 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.
+//
+//
+#include <arrow/api.h>
+#include <arrow/io/api.h>
+#include <parquet/arrow/reader.h>
+#include <parquet/arrow/writer.h>
+#include <parquet/exception.h>
+
+// [[Rcpp::export]]
+std::shared_ptr<arrow::Table> read_parquet_file(std::string filename) {
+ std::shared_ptr<arrow::io::ReadableFile> infile;
+ PARQUET_THROW_NOT_OK(arrow::io::ReadableFile::Open(
+ filename, arrow::default_memory_pool(), &infile));
+
+ std::unique_ptr<parquet::arrow::FileReader> reader;
+ PARQUET_THROW_NOT_OK(
+ parquet::arrow::OpenFile(infile, arrow::default_memory_pool(), &reader));
+ std::shared_ptr<arrow::Table> table;
+ PARQUET_THROW_NOT_OK(reader->ReadTable(&table));
+
+ return table;
+}