From c0e0c7cfe51aa6fcbf566e6ab365e650491d01a4 Mon Sep 17 00:00:00 2001
From: Kenny Daniel <platypii@gmail.com>
Date: Wed, 26 Nov 2025 16:04:47 -0800
Subject: [PATCH] Fix BYTE_STREAM_SPLIT with data page v2 and compression

---
 src/datapage.js                               |   2 +-
 test/files/byte_stream_split_v2.json          |   7 +
 test/files/byte_stream_split_v2.metadata.json | 121 ++++++++++++++++++
 test/files/byte_stream_split_v2.parquet       | Bin 0 -> 772 bytes
 4 files changed, 129 insertions(+), 1 deletion(-)
 create mode 100644 test/files/byte_stream_split_v2.json
 create mode 100644 test/files/byte_stream_split_v2.metadata.json
 create mode 100644 test/files/byte_stream_split_v2.parquet

diff --git a/src/datapage.js b/src/datapage.js
index 9749fdf..fe4c28b 100644
--- a/src/datapage.js
+++ b/src/datapage.js
@@ -193,7 +193,7 @@ export function readDataPageV2(compressedBytes, ph, columnDecoder) {
     dataPage = new Array(nValues)
     deltaByteArray(pageReader, nValues, dataPage)
   } else if (daph2.encoding === 'BYTE_STREAM_SPLIT') {
-    dataPage = byteStreamSplit(reader, nValues, type, element.type_length)
+    dataPage = byteStreamSplit(pageReader, nValues, type, element.type_length)
   } else {
     throw new Error(`parquet unsupported encoding: ${daph2.encoding}`)
   }
diff --git a/test/files/byte_stream_split_v2.json b/test/files/byte_stream_split_v2.json
new file mode 100644
index 0000000..20f8c6c
--- /dev/null
+++ b/test/files/byte_stream_split_v2.json
@@ -0,0 +1,7 @@
+[
+  [1.5, 10.1],
+  [2.5, 20.2],
+  [3.5, 30.3],
+  [4.5, 40.4],
+  [5.5, 50.5]
+]
diff --git a/test/files/byte_stream_split_v2.metadata.json b/test/files/byte_stream_split_v2.metadata.json
new file mode 100644
index 0000000..946a709
--- /dev/null
+++ b/test/files/byte_stream_split_v2.metadata.json
@@ -0,0 +1,121 @@
+{
+  "version": 2,
+  "schema": [
+    {
+      "repetition_type": "REQUIRED",
+      "name": "schema",
+      "num_children": 2
+    },
+    {
+      "type": "DOUBLE",
+      "repetition_type": "OPTIONAL",
+      "name": "float_col"
+    },
+    {
+      "type": "DOUBLE",
+      "repetition_type": "OPTIONAL",
+      "name": "double_col"
+    }
+  ],
+  "num_rows": 5,
+  "row_groups": [
+    {
+      "columns": [
+        {
+          "file_offset": 0,
+          "meta_data": {
+            "type": "DOUBLE",
+            "encodings": [
+              "RLE",
+              "BYTE_STREAM_SPLIT"
+            ],
+            "path_in_schema": [
+              "float_col"
+            ],
+            "codec": "SNAPPY",
+            "num_values": 5,
+            "total_uncompressed_size": 110,
+            "total_compressed_size": 87,
+            "data_page_offset": 4,
+            "statistics": {
+              "max": 5.5,
+              "min": 1.5,
+              "null_count": 0,
+              "max_value": 5.5,
+              "min_value": 1.5,
+              "is_max_value_exact": true,
+              "is_min_value_exact": true
+            },
+            "encoding_stats": [
+              {
+                "page_type": "DATA_PAGE",
+                "encoding": "BYTE_STREAM_SPLIT",
+                "count": 1
+              }
+            ],
+            "size_statistics": {
+              "repetition_level_histogram": [],
+              "definition_level_histogram": [
+                0,
+                5
+              ]
+            }
+          }
+        },
+        {
+          "file_offset": 0,
+          "meta_data": {
+            "type": "DOUBLE",
+            "encodings": [
+              "RLE",
+              "BYTE_STREAM_SPLIT"
+            ],
+            "path_in_schema": [
+              "double_col"
+            ],
+            "codec": "SNAPPY",
+            "num_values": 5,
+            "total_uncompressed_size": 110,
+            "total_compressed_size": 97,
+            "data_page_offset": 91,
+            "statistics": {
+              "max": 50.5,
+              "min": 10.1,
+              "null_count": 0,
+              "max_value": 50.5,
+              "min_value": 10.1,
+              "is_max_value_exact": true,
+              "is_min_value_exact": true
+            },
+            "encoding_stats": [
+              {
+                "page_type": "DATA_PAGE",
+                "encoding": "BYTE_STREAM_SPLIT",
+                "count": 1
+              }
+            ],
+            "size_statistics": {
+              "repetition_level_histogram": [],
+              "definition_level_histogram": [
+                0,
+                5
+              ]
+            }
+          }
+        }
+      ],
+      "total_byte_size": 220,
+      "num_rows": 5,
+      "file_offset": 4,
+      "total_compressed_size": 184
+    }
+  ],
+  "key_value_metadata": [
+    {
+      "key": "ARROW:schema",
+      "value": "/////7AAAAAQAAAAAAAKAAwABgAFAAgACgAAAAABBAAMAAAACAAIAAAABAAIAAAABAAAAAIAAABIAAAABAAAAND///8AAAEDEAAAABwAAAAEAAAAAAAAAAoAAABkb3VibGVfY29sAADC////AAACABAAFAAIAAYABwAMAAAAEAAQAAAAAAABAxAAAAAgAAAABAAAAAAAAAAJAAAAZmxvYXRfY29sAAYACAAGAAYAAAAAAAIAAAAAAA=="
+    }
+  ],
+  "created_by": "parquet-cpp-arrow version 22.0.0",
+  "metadata_length": 576
+}
diff --git a/test/files/byte_stream_split_v2.parquet b/test/files/byte_stream_split_v2.parquet
new file mode 100644
index 0000000000000000000000000000000000000000..b0fdf54a15809b5457783b3578ccf23c49e33c60
GIT binary patch
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literal 0
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