From bf268e141cea1d5f94f5b6829e21b9d809be4cb0 Mon Sep 17 00:00:00 2001
From: Johan Levin <johan13@gmail.com>
Date: Wed, 19 Feb 2025 20:07:49 +0100
Subject: [PATCH] Use prepended length for bit-packed hybrid bool columns (#62)

---
 src/datapage.js                      |   3 +-
 src/encoding.js                      |   2 +-
 test/files/boolean_rle.json          |  17 ++++++++
 test/files/boolean_rle.metadata.json |  61 +++++++++++++++++++++++++++
 test/files/boolean_rle.parquet       | Bin 0 -> 432 bytes
 5 files changed, 81 insertions(+), 2 deletions(-)
 create mode 100644 test/files/boolean_rle.json
 create mode 100644 test/files/boolean_rle.metadata.json
 create mode 100644 test/files/boolean_rle.parquet

diff --git a/src/datapage.js b/src/datapage.js
index 69c79af..5d0b07c 100644
--- a/src/datapage.js
+++ b/src/datapage.js
@@ -38,7 +38,8 @@ export function readDataPage(bytes, daph, schemaPath, { type }) {
     const bitWidth = type === 'BOOLEAN' ? 1 : view.getUint8(reader.offset++)
     if (bitWidth) {
       dataPage = new Array(nValues)
-      readRleBitPackedHybrid(reader, bitWidth, view.byteLength - reader.offset, dataPage)
+      const encodedLength = type === 'BOOLEAN' ? 0 : view.byteLength - reader.offset
+      readRleBitPackedHybrid(reader, bitWidth, encodedLength, dataPage)
     } else {
       dataPage = new Uint8Array(nValues) // nValue zeroes
     }
diff --git a/src/encoding.js b/src/encoding.js
index 5d315a3..6f1f4ab 100644
--- a/src/encoding.js
+++ b/src/encoding.js
@@ -22,7 +22,7 @@ export function bitWidth(value) {
  */
 export function readRleBitPackedHybrid(reader, width, length, output) {
   if (!length) {
-    // length = reader.view.getUint32(reader.offset, true)
+    length = reader.view.getUint32(reader.offset, true)
     reader.offset += 4
   }
   let seen = 0
diff --git a/test/files/boolean_rle.json b/test/files/boolean_rle.json
new file mode 100644
index 0000000..7c29a74
--- /dev/null
+++ b/test/files/boolean_rle.json
@@ -0,0 +1,17 @@
+[
+    [1],
+    [1],
+    [1],
+    [1],
+    [1],
+    [null],
+    [null],
+    [null],
+    [null],
+    [null],
+    [0],
+    [0],
+    [0],
+    [0],
+    [0]
+]
diff --git a/test/files/boolean_rle.metadata.json b/test/files/boolean_rle.metadata.json
new file mode 100644
index 0000000..43c937a
--- /dev/null
+++ b/test/files/boolean_rle.metadata.json
@@ -0,0 +1,61 @@
+{
+  "created_by": "Polars",
+  "key_value_metadata": [
+    {
+      "key": "ARROW:schema",
+      "value": "/////3YAAAAEAAAA8v///xQAAAAEAAEAAAAKAAsACAAKAAQA+P///wwAAAAIAAgAAAAEAAEAAAAEAAAA7P///ywAAAAgAAAAGAAAAAEGAAAQABIABAAQABEACAAAAAwAAAAAAPz///8EAAQADQAAAEJvb2xlYW5Db2x1bW4A"
+    }
+  ],
+  "metadata_length": 308,
+  "num_rows": 15,
+  "row_groups": [
+    {
+      "columns": [
+        {
+          "column_index_length": 17,
+          "column_index_offset": 89,
+          "crypto_metadata": 17,
+          "file_offset": 47,
+          "meta_data": {
+            "codec": "SNAPPY",
+            "data_page_offset": 4,
+            "encodings": [
+              "RLE"
+            ],
+            "num_values": 15,
+            "path_in_schema": [
+              "BooleanColumn"
+            ],
+            "statistics": {
+              "max_value": true,
+              "min_value": false,
+              "null_count": 5
+            },
+            "total_compressed_size": 43,
+            "total_uncompressed_size": 41,
+            "type": "BOOLEAN"
+          },
+          "offset_index_length": 10,
+          "offset_index_offset": 106
+        }
+      ],
+      "file_offset": 4,
+      "num_rows": 15,
+      "ordinal": 0,
+      "total_byte_size": 41,
+      "total_compressed_size": 43
+    }
+  ],
+  "schema": [
+    {
+      "name": "root",
+      "num_children": 1
+    },
+    {
+      "name": "BooleanColumn",
+      "repetition_type": "OPTIONAL",
+      "type": "BOOLEAN"
+    }
+  ],
+  "version": 1
+}
diff --git a/test/files/boolean_rle.parquet b/test/files/boolean_rle.parquet
new file mode 100644
index 0000000000000000000000000000000000000000..00413192c8a3356912f7d9de7d0efce474c131c0
GIT binary patch
literal 432
zcma)3!AiqG5Z#R$LQz5JELm8h2nNA|)J84hWzq(%9!zpb=tW4S=pk*O(YA^o<k@fW
zgPdIj#gnt_JZ9gUH_L8}X&V?Q*lB?WwqEL_vCp~78O3I>LV0cb^$Qp<3AS`M!m29A
z#k5zIPm?KF!V{^;eCPb9Rc=|5JZN)j5)CGma3B+82bOGIuFk6J5iD}tv;O!o;YlTx
zf2;mKPJD1^igymXjIQGOj>wvfX1eQ`rZ@RnefKb)6z&^8)X^CtMWj=APW3YRuFcUk
zVvRjS!UPXu;uj0e4-oHv>x}qR^UsDi<b_sXq#?m@fT6)i`%xGjV*El)UFuJ;uSZ8$
h^U=|=9OlP;!uBW+khykTmBp-<O3|AI^c^w%)h9wOSn&V=

literal 0
HcmV?d00001