1 files changed, 81 insertions, 0 deletions
diff --git a/src/arrow/js/bin/print-buffer-alignment.js b/src/arrow/js/bin/print-buffer-alignment.js
new file mode 100755
index 000000000..4c3260397
--- /dev/null
+++ b/src/arrow/js/bin/print-buffer-alignment.js
@@ -0,0 +1,81 @@
+#! /usr/bin/env node
+
+// 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.
+
+// @ts-check
+
+const fs = require('fs');
+const path = require('path');
+const extension = process.env.ARROW_JS_DEBUG === 'src' ? '.ts' : '';
+const { RecordBatch, AsyncMessageReader } = require(`../index${extension}`);
+const { VectorLoader } = require(`../targets/apache-arrow/visitor/vectorloader`);
+
+(async () => {
+
+    const readable = process.argv.length < 3 ? process.stdin : fs.createReadStream(path.resolve(process.argv[2]));
+    const reader = new AsyncMessageReader(readable);
+
+    let schema, recordBatchIndex = 0, dictionaryBatchIndex = 0;
+
+    for await (let message of reader) {
+
+        let bufferRegions = [];
+
+        if (message.isSchema()) {
+            schema = message.header();
+            continue;
+        } else if (message.isRecordBatch()) {
+            const header = message.header();
+            bufferRegions = header.buffers;
+            const body = await reader.readMessageBody(message.bodyLength);
+            const recordBatch = loadRecordBatch(schema, header, body);
+            console.log(`record batch ${++recordBatchIndex}: ${JSON.stringify({
+                offset: body.byteOffset,
+                length: body.byteLength,
+                numRows: recordBatch.length,
+            })}`);
+        } else if (message.isDictionaryBatch()) {
+            const header = message.header();
+            bufferRegions = header.data.buffers;
+            const type = schema.dictionaries.get(header.id);
+            const body = await reader.readMessageBody(message.bodyLength);
+            const recordBatch = loadDictionaryBatch(header.data, body, type);
+            console.log(`dictionary batch ${++dictionaryBatchIndex}: ${JSON.stringify({
+                offset: body.byteOffset,
+                length: body.byteLength,
+                numRows: recordBatch.length,
+                dictionaryId: header.id,
+            })}`);
+        }
+
+        bufferRegions.forEach(({ offset, length }, i) => {
+            console.log(`\tbuffer ${i + 1}: { offset: ${offset},  length: ${length} }`);
+        });
+    }
+
+    await reader.return();
+
+})().catch((e) => { console.error(e); process.exit(1); });
+
+function loadRecordBatch(schema, header, body) {
+    return new RecordBatch(schema, header.length, new VectorLoader(body, header.nodes, header.buffers, new Map()).visitMany(schema.fields));
+}
+
+function loadDictionaryBatch(header, body, dictionaryType) {
+    return RecordBatch.new(new VectorLoader(body, header.nodes, header.buffers, new Map()).visitMany([dictionaryType]));
+}