Fix reverseChunked(by:) Method Implementation (#465)

Author: jiahan-wu

Sources/PostgresNIO/Data/PostgresData+Numeric.swift

@@ -268,16 +268,10 @@ private extension Collection {
     // splits the collection into chunks of the supplied size
     // if the collection is not evenly divisible, the first chunk will be smaller
     func reverseChunked(by maxSize: Int) -> [SubSequence] {
-        var lastDistance = 0
         var chunkStartIndex = self.startIndex
         return stride(from: 0, to: self.count, by: maxSize).reversed().map { current in
-            let distance = (self.count - current) - lastDistance
-            lastDistance = distance
-            let chunkEndOffset = Swift.min(
-                self.distance(from: chunkStartIndex, to: self.endIndex),
-                distance
-            )
-            let chunkEndIndex = self.index(chunkStartIndex, offsetBy: chunkEndOffset)
+            let distance = self.count - current
+            let chunkEndIndex = self.index(self.startIndex, offsetBy: distance)
             defer { chunkStartIndex = chunkEndIndex }
             return self[chunkStartIndex..<chunkEndIndex]
         }

Tests/IntegrationTests/PostgresNIOTests.swift

@@ -617,21 +617,25 @@ final class PostgresNIOTests: XCTestCase {
         let a = PostgresNumeric(string: "123456.789123")!
         let b = PostgresNumeric(string: "-123456.789123")!
         let c = PostgresNumeric(string: "3.14159265358979")!
+        let d = PostgresNumeric(string: "1234567898765")!
         var rows: PostgresQueryResult?
         XCTAssertNoThrow(rows = try conn?.query("""
         select
             $1::numeric as a,
             $2::numeric as b,
-            $3::numeric as c
+            $3::numeric as c,
+            $4::numeric as d
         """, [
             .init(numeric: a),
             .init(numeric: b),
-            .init(numeric: c)
+            .init(numeric: c),
+            .init(numeric: d)
         ]).wait())
         let row = rows?.first?.makeRandomAccess()
         XCTAssertEqual(row?[data: "a"].decimal, Decimal(string: "123456.789123")!)
         XCTAssertEqual(row?[data: "b"].decimal, Decimal(string: "-123456.789123")!)
         XCTAssertEqual(row?[data: "c"].decimal, Decimal(string: "3.14159265358979")!)
+        XCTAssertEqual(row?[data: "d"].decimal, Decimal(string: "1234567898765")!)
     }
 
     func testDecimalStringSerialization() {