Add a min-max heap implementation that can be used to back a priority queue

.swiftpm/xcode/xcshareddata/xcschemes/PriorityQueueModule.xcscheme

@@ -0,0 +1,77 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "1250"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "PriorityQueueModule"
+               BuildableName = "PriorityQueueModule"
+               BlueprintName = "PriorityQueueModule"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "PriorityQueueTests"
+               BuildableName = "PriorityQueueTests"
+               BlueprintName = "PriorityQueueTests"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </TestableReference>
+      </Testables>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "PriorityQueueModule"
+            BuildableName = "PriorityQueueModule"
+            BlueprintName = "PriorityQueueModule"
+            ReferencedContainer = "container:">
+         </BuildableReference>
+      </MacroExpansion>
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>

.swiftpm/xcode/xcshareddata/xcschemes/swift-collections-Package.xcscheme

@@ -132,6 +132,20 @@
                ReferencedContainer = "container:">
             </BuildableReference>
          </BuildActionEntry>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "PriorityQueueModule"
+               BuildableName = "PriorityQueueModule"
+               BlueprintName = "PriorityQueueModule"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </BuildActionEntry>
       </BuildActionEntries>
    </BuildAction>
    <TestAction
@@ -170,6 +184,16 @@
                ReferencedContainer = "container:">
             </BuildableReference>
          </TestableReference>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "PriorityQueueTests"
+               BuildableName = "PriorityQueueTests"
+               BlueprintName = "PriorityQueueTests"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </TestableReference>
       </Testables>
    </TestAction>
    <LaunchAction

.swiftpm/xcode/xcshareddata/xcschemes/swift-collections-benchmark.xcscheme

@@ -48,6 +48,16 @@
                ReferencedContainer = "container:">
             </BuildableReference>
          </TestableReference>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "PriorityQueueTests"
+               BuildableName = "PriorityQueueTests"
+               BlueprintName = "PriorityQueueTests"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </TestableReference>
       </Testables>
    </TestAction>
    <LaunchAction

Benchmarks/Benchmarks/Library.json

@@ -764,6 +764,46 @@
         }
       ]
     },
+    {
+      "kind": "group",
+      "title": "PriorityQueue",
+      "contents": [
+        {
+          "kind": "chart",
+          "title": "operations",
+          "tasks": [
+            "Heap<Int> init from range",
+            "Heap<Int> insert",
+            "Heap<Int> insert(contentsOf:)",
+            "Heap<Int> popMax",
+            "Heap<Int> popMin"
+          ]
+        },
+        {
+          "kind": "chart",
+          "title": "initializers",
+          "tasks": [
+            "Heap<Int> init from range"
+          ]
+        },
+        {
+          "kind": "chart",
+          "title": "insert",
+          "tasks": [
+            "Heap<Int> insert",
+            "Heap<Int> insert(contentsOf:)"
+          ]
+        },
+        {
+          "kind": "chart",
+          "title": "remove",
+          "tasks": [
+            "Heap<Int> popMax",
+            "Heap<Int> popMin"
+          ]
+        }
+      ]
+    },
     {
       "kind": "group",
       "title": "Against other Swift collections",

Benchmarks/Benchmarks/PriorityQueueBenchmarks.swift

@@ -0,0 +1,122 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift Collections open source project
+//
+// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+//
+//===----------------------------------------------------------------------===//
+
+import CollectionsBenchmark
+import PriorityQueueModule
+import CppBenchmarks
+
+extension Benchmark {
+  public mutating func addHeapBenchmarks() {
+    self.addSimple(
+      title: "Heap<Int> init from range",
+      input: Int.self
+    ) { size in
+      blackHole(Heap(0..<size))
+    }
+
+    self.addSimple(
+      title: "Heap<Int> insert",
+      input: [Int].self
+    ) { input in
+      var queue = Heap<Int>()
+      for i in input {
+        queue.insert(i)
+      }
+      precondition(queue.count == input.count)
+      blackHole(queue)
+    }
+
+    self.add(
+      title: "Heap<Int> insert(contentsOf:)",
+      input: ([Int], [Int]).self
+    ) { (existing, new) in
+      return { timer in
+        var queue = Heap(existing)
+        queue.insert(contentsOf: new)
+        precondition(queue.count == existing.count + new.count)
+        blackHole(queue)
+      }
+    }
+
+    self.add(
+      title: "Heap<Int> popMax",
+      input: [Int].self
+    ) { input in
+      return { timer in
+        var queue = Heap(input)
+        timer.measure {
+          while let max = queue.popMax() {
+            blackHole(max)
+          }
+        }
+        precondition(queue.isEmpty)
+        blackHole(queue)
+      }
+    }
+
+    self.add(
+      title: "Heap<Int> popMin",
+      input: [Int].self
+    ) { input in
+      return { timer in
+        var queue = Heap(input)
+        timer.measure {
+          while let min = queue.popMin() {
+            blackHole(min)
+          }
+        }
+        precondition(queue.isEmpty)
+        blackHole(queue)
+      }
+    }
+  }
+}
+
+// MARK: -
+
+extension Benchmark {
+  public mutating func addCFBinaryHeapBenchmarks() {
+    #if os(macOS) || os(iOS) || os(watchOS) || os(tvOS)
+    self.addSimple(
+      title: "CFBinaryHeap insert",
+      input: [Int].self
+    ) { input in
+      let heap = BinaryHeap()
+      for i in input {
+        heap.insert(i)
+      }
+      precondition(heap.count == input.count)
+      blackHole(heap)
+    }
+
+    self.add(
+      title: "CFBinaryHeap removeMinimumValue",
+      input: [Int].self
+    ) { input in
+      return { timer in
+        let heap = BinaryHeap()
+        for i in input {
+          heap.insert(i)
+        }
+
+        timer.measure {
+          while heap.count > 0 {
+            let min = heap.popMinimum()
+            blackHole(min)
+          }
+        }
+        precondition(heap.count == 0)
+        blackHole(heap)
+      }
+    }
+    #endif
+  }
+}

Benchmarks/CppBenchmarks/include/BinaryHeap.h

@@ -0,0 +1,29 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift Collections open source project
+//
+// Copyright (c) 2021 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef BinaryHeap_h
+#define BinaryHeap_h
+
+#if __APPLE__ // CFBinaryHeap only exists on Apple platforms
+
+@import Foundation;
+
+@interface BinaryHeap: NSObject
+
+@property (nonatomic, readonly) NSUInteger count;
+
+- (void)insert:(NSInteger)value;
+- (NSInteger)popMinimum;
+
+@end
+
+#endif // __APPLE__
+#endif /* BinaryHeap_h */

Benchmarks/CppBenchmarks/include/module.modulemap

@@ -4,6 +4,6 @@ module CppBenchmarks {
   header "DequeBenchmarks.h"
   header "UnorderedSetBenchmarks.h"
   header "UnorderedMapBenchmarks.h"
+  header "BinaryHeap.h"
   export *
 }
-