Fix duckdb empty block (#91)

src/encoding.js

@@ -22,9 +22,10 @@ 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
   }
+  const startOffset = reader.offset
   let seen = 0
   while (seen < output.length) {
     const header = readVarInt(reader)
@@ -38,7 +39,7 @@ export function readRleBitPackedHybrid(reader, width, length, output) {
       seen += count
     }
   }
-  // assert(reader.offset - startOffset === length)
+  reader.offset = startOffset + length // duckdb writes an empty block
 }
 
 /**

test/encoding.test.js

@@ -110,7 +110,7 @@ describe('readBitPacked', () => {
     const reader = { view, offset: 0 }
 
     const values = new Array(72)
-    readRleBitPackedHybrid(reader, 17, 72, values)
+    readRleBitPackedHybrid(reader, 17, 154, values)
     expect(reader.offset).toBe(154)
     expect(values).toEqual([
       131071, 0, 0, 0, 0, 0, 0, 0,

test/files/issue90.metadata.json

@@ -0,0 +1,53 @@
+{
+  "version": 1,
+  "schema": [
+    {
+      "repetition_type": "REQUIRED",
+      "name": "duckdb_schema",
+      "num_children": 1
+    },
+    {
+      "type": "DOUBLE",
+      "repetition_type": "OPTIONAL",
+      "name": "elb_01yr_imp_val"
+    }
+  ],
+  "num_rows": 6144,
+  "row_groups": [
+    {
+      "columns": [
+        {
+          "file_offset": 0,
+          "meta_data": {
+            "type": "DOUBLE",
+            "encodings": [
+              "PLAIN"
+            ],
+            "path_in_schema": [
+              "elb_01yr_imp_val"
+            ],
+            "codec": "SNAPPY",
+            "num_values": 6144,
+            "total_uncompressed_size": 45059,
+            "total_compressed_size": 44650,
+            "data_page_offset": 4,
+            "statistics": {
+              "max": 449097851.5197593,
+              "min": 0,
+              "null_count": 610,
+              "max_value": 449097851.5197593,
+              "min_value": 0,
+              "is_max_value_exact": true,
+              "is_min_value_exact": true
+            }
+          }
+        }
+      ],
+      "total_byte_size": 45059,
+      "num_rows": 6144,
+      "file_offset": 4
+    }
+  ],
+  "created_by": "DuckDB version v1.3.0 (build 71c5c07cdd)",
+  "metadata_length": 198
+}