From 4ba36051fd06a920aedd51c93a15703d4b152332 Mon Sep 17 00:00:00 2001
From: Frizlab <fload@me.com>
Date: Sun, 28 Mar 2021 19:28:51 +0200
Subject: [PATCH 1/2] Make firstRange and lastRange methods of the DataProtocol
 mirror macOS foundation when data is empty

---
 Sources/Foundation/DataProtocol.swift | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Sources/Foundation/DataProtocol.swift b/Sources/Foundation/DataProtocol.swift
index 3e9f88cf22..d0ed2c0a6a 100644
--- a/Sources/Foundation/DataProtocol.swift
+++ b/Sources/Foundation/DataProtocol.swift
@@ -137,6 +137,9 @@ extension DataProtocol {
     }
     
     public func firstRange<D: DataProtocol, R: RangeExpression>(of data: D, in range: R) -> Range<Index>? where R.Bound == Index {
+        guard !data.isEmpty else {
+            return nil
+        }
         let r = range.relative(to: self)
         let rangeCount = distance(from: r.lowerBound, to: r.upperBound)
         if rangeCount < data.count {
@@ -166,6 +169,9 @@ extension DataProtocol {
     }
     
     public func lastRange<D: DataProtocol, R: RangeExpression>(of data: D, in range: R) -> Range<Index>? where R.Bound == Index {
+        guard !data.isEmpty else {
+            return nil
+        }
         let r = range.relative(to: self)
         let rangeCount = distance(from: r.lowerBound, to: r.upperBound)
         if rangeCount < data.count {

From 090eb4bc2a3e21afad7bfe79a03816e9039172b9 Mon Sep 17 00:00:00 2001
From: Frizlab <fload@me.com>
Date: Mon, 29 Mar 2021 09:19:26 +0200
Subject: [PATCH 2/2] Add tests for first and last range w/ empty data searched

---
 Tests/Foundation/Tests/TestNSData.swift | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Tests/Foundation/Tests/TestNSData.swift b/Tests/Foundation/Tests/TestNSData.swift
index 5e77aee13f..ec36a00a5c 100644
--- a/Tests/Foundation/Tests/TestNSData.swift
+++ b/Tests/Foundation/Tests/TestNSData.swift
@@ -212,6 +212,8 @@ class TestNSData: LoopbackServerTest {
             ("testCopyBytes", testCopyBytes),
             ("testCustomDeallocator", testCustomDeallocator),
             ("testDataInSet", testDataInSet),
+            ("testFirstRangeEmptyData", testFirstRangeEmptyData),
+            ("testLastRangeEmptyData", testLastRangeEmptyData),
             ("testEquality", testEquality),
             ("testGenericAlgorithms", testGenericAlgorithms),
             ("testInitializationWithArray", testInitializationWithArray),
@@ -1194,6 +1196,16 @@ extension TestNSData {
         XCTAssertEqual(s.count, 2, "Expected only two entries in the Set")
     }
     
+    func testFirstRangeEmptyData() {
+        let d = Data([1, 2, 3])
+        XCTAssertNil(d.firstRange(of: Data()))
+    }
+    
+    func testLastRangeEmptyData() {
+        let d = Data([1, 2, 3])
+        XCTAssertNil(d.lastRange(of: Data()))
+    }
+    
     func testReplaceSubrange() {
         var hello = dataFrom("Hello")
         let world = dataFrom("World")