UnsafeBufferPointer.swift.gyb

// RUN: %target-run-simple-swiftgyb
// REQUIRES: executable_test

// FIXME: The optimized-build behavior of UnsafeBufferPointer bounds/overflow
// checking cannot be tested. The standard library always compiles with debug
// checking enabled, so the behavior of the optimized test depends on whether
// the inlining heuristics decide to inline these methods. To fix this, we need
// a way to force @inlinable UnsafeBufferPointer methods to be emitted inside
// the client code, and thereby subject the stdlib implementation to the test
// case's compile options.
//
// REQUIRES: swift_test_mode_optimize_none

import StdlibUnittest
import StdlibCollectionUnittest

// Tests

func allocateForRawBuffer(count: Int) -> UnsafeMutableRawPointer {
  return UnsafeMutableRawPointer.allocate(byteCount: count, alignment: 1)
}
func allocateForBuffer<T>(count: Int) -> UnsafeMutablePointer<T> {
  return UnsafeMutablePointer<T>.allocate(capacity: count)
}
func deallocateForRawBuffer(
  _ memory: UnsafeMutableRawPointer, count: Int
) {
  memory.deallocate()
}
func deallocateForBuffer<T>(
  _ memory: UnsafeMutablePointer<T>, count: Int
) {
  memory.deallocate()
}

// Initialize memory with arbitrary equatable, comparable values.
func initUnsafeRawBufferPointer(_ b: UnsafeMutableRawBufferPointer) {
  _ = b.initializeMemory(as: UInt8.self, from: UInt8(0)..<numericCast(b.count))
}
func initUnsafeBufferPointer(_ b: UnsafeMutableBufferPointer<Float>) {
  _ = b.initialize(from: (0..<b.count).lazy.map {Float($0)})
}

// Test Suites

var UnsafeBufferPointerTestSuite = TestSuite("UnsafeBufferPointer")
var UnsafeMutableBufferPointerTestSuite = TestSuite("UnsafeMutableBufferPointer")
var UnsafeRawBufferPointerTestSuite = TestSuite("UnsafeRawBufferPointer")
var UnsafeMutableRawBufferPointerTestSuite = TestSuite("UnsafeMutableRawBufferPointer")

% for (SelfName, IsMutable, IsRaw, SelfType, PointerType) in [
%   ('UnsafeBufferPointer', False, False, 'UnsafeBufferPointer<Float>', 'UnsafePointer<Float>'),
%   ('UnsafeMutableBufferPointer', True, False, 'UnsafeMutableBufferPointer<Float>', 'UnsafeMutablePointer<Float>'),
%   ('UnsafeRawBufferPointer', False, True, 'UnsafeRawBufferPointer', 'UnsafeRawPointer'),
%   ('UnsafeMutableRawBufferPointer', True, True, 'UnsafeMutableRawBufferPointer', 'UnsafeMutableRawPointer')
% ]:
%   Raw = 'Raw' if IsRaw else ''
%   Element = 'UInt8' if IsRaw else 'Float'

${SelfName}TestSuite.test("AssociatedTypes") {
  expectRandomAccessCollectionAssociatedTypes(
    collectionType: ${SelfType}.self,
%   if IsRaw:
    iteratorType: ${SelfType}.Iterator.self,
%   else:
    iteratorType: UnsafeBufferPointer<Float>.Iterator.self,
%   end
    subSequenceType: Slice<${SelfType}>.self,
    indexType: Int.self,
    indicesType: Range<Int>.self)

  expect${'Mutable' if IsMutable else ''}CollectionType(${SelfType}.self)
}

${SelfName}TestSuite.test("rebasing") {
  let rawbuffer = UnsafeMutableRawBufferPointer.allocate(
    byteCount: 4 * MemoryLayout<Int>.stride, alignment: MemoryLayout<UInt>.alignment)
  defer { rawbuffer.deallocate() }

  rawbuffer.copyBytes(from: [0, 1, 2, 3])

%   if IsRaw:
  let buffer = rawbuffer
%   else:
  let intPtr = rawbuffer.baseAddress!.bindMemory(to: Int.self, capacity: 4)
  let buffer = UnsafeMutableBufferPointer(start: intPtr, count: 4)
%   end

  for i in buffer.indices {
    let slice = buffer[i..<buffer.endIndex]
    let rebased = ${SelfName}(rebasing: slice)
    expectEqual(rebased.startIndex, 0)
    expectEqual(rebased.endIndex, rebased.count)
    expectEqual(rebased.endIndex, buffer.endIndex - i)
    expectEqual(rebased[0], slice[i])
    if rebased.count > 1 {
      expectEqual(rebased[1], slice[i + 1])

      // Rebase again. Tests Mutable->Immutable initializer
      // and an rvalue slice with literal indices.
      let rebased2 = ${SelfName}(rebasing: rebased[1..<2])
      expectEqual(rebased2.startIndex, 0)
      expectEqual(rebased2.endIndex, 1)
      expectEqual(rebased2[0], slice[i + 1])
    }
  }

  let rebased3 = ${SelfType}(rebasing: ${SelfType}(start: nil, count: 0)[...])
  expectEqual(rebased3.baseAddress, nil)

%   if not IsMutable:
%   if IsRaw:
  let rebased4 = ${SelfType}(rebasing: UnsafeMutableRawBufferPointer(start: nil, count: 0)[...])
  expectEqual(rebased4.baseAddress, nil)
%   else:
  let rebased4 = ${SelfType}(rebasing: UnsafeMutableBufferPointer<Float>(start: nil, count: 0)[...])
  expectEqual(rebased4.baseAddress, nil)
%   end # !Raw
%   end # Mutable
}

// Allocate two buffers. Initialize one and copy it into the other. Pass those
// to the specified generic collection test function `checkBuffers`.
func checkWithExpectedBuffer(checkBuffers: (${SelfType}, ${SelfType}) -> Void) {
  // A collection just big enough to be sliced up interestingly.
  let elementCount = 4

%   if IsRaw:
  var memory: UnsafeMutableRawPointer
  var memoryCopy: UnsafeMutableRawPointer
%   else:
  var memory: UnsafeMutablePointer<Float>
  var memoryCopy: UnsafeMutablePointer<Float>
%   end

  memory = allocateFor${Raw}Buffer(count: elementCount)
  defer { deallocateFor${Raw}Buffer(
      memory, count: elementCount) }

  memoryCopy = allocateFor${Raw}Buffer(count: elementCount)
  defer { deallocateFor${Raw}Buffer(memoryCopy, count: elementCount) }

  initUnsafe${Raw}BufferPointer(
    UnsafeMutable${Raw}BufferPointer(start: memory, count: elementCount))

  let buffer = ${SelfType}(start: memory, count: elementCount)

  let expectedBuffer = UnsafeMutable${Raw}BufferPointer(start: memoryCopy,
    count: elementCount)

%   if IsRaw:
    expectedBuffer.copyMemory(from: UnsafeRawBufferPointer(buffer))
%   else:
    _ = expectedBuffer.initialize(from: buffer)
%   end

  let expected = ${SelfType}(
    start: expectedBuffer.baseAddress, count: expectedBuffer.count)

  checkBuffers(expected, buffer)
}

${SelfName}TestSuite.test("RandomAccessCollection") {
  checkWithExpectedBuffer { (expected: ${SelfType}, buffer: ${SelfType}) in
    checkRandomAccessCollection(expected, buffer,
      sameValue: { (a: ${Element}, b: ${Element}) in a == b })
  }
}

${SelfName}TestSuite.test("nilBaseAddress") {
  let emptyBuffer = ${SelfType}(start: nil, count: 0)
  expectNil(emptyBuffer.baseAddress)
  expectEqual(0, emptyBuffer.count)
  expectTrue(emptyBuffer.startIndex == emptyBuffer.endIndex)

  var iter = emptyBuffer.makeIterator()
  expectNil(iter.next())

  expectEqualSequence([], emptyBuffer)
}

${SelfName}TestSuite.test("nonNilButEmpty") {
  let emptyAllocated = UnsafeMutablePointer<Float>.allocate(capacity: 0)
  defer { emptyAllocated.deallocate() }

  let emptyBuffer = ${SelfType}(start: ${PointerType}(emptyAllocated), count: 0)
  expectEqual(emptyAllocated, emptyBuffer.baseAddress)
  expectEqual(0, emptyBuffer.count)
  expectTrue(emptyBuffer.startIndex == emptyBuffer.endIndex)

  var iter = emptyBuffer.makeIterator()
  expectNil(iter.next())

  expectEqualSequence([], emptyBuffer)
}

%   if IsRaw:
${SelfName}TestSuite.test("nonNilNonEmpty") {
  let count = 4
  let allocated = UnsafeMutableRawPointer.allocate(byteCount: count, alignment: 1)
  defer { allocated.deallocate() }
  let uint8Ptr = allocated.initializeMemory(as: UInt8.self, repeating: 1, count: count)
  uint8Ptr[count - 1] = 2

  let buffer = ${SelfType}(start: ${PointerType}(allocated), count: count - 1)
  expectEqual(allocated, buffer.baseAddress)
  expectEqual(count - 1, buffer.count)
  expectEqual(count - 1, buffer.endIndex - buffer.startIndex)

  uint8Ptr[1] = 0
  expectEqual(1, buffer[0])
  expectEqual(0, buffer[1])
  expectEqual(1, buffer[2])

  var iter = buffer.makeIterator()
  expectEqual(1, iter.next())
  expectEqual(0, iter.next())
  expectEqual(1, iter.next())
  expectNil(iter.next())

  expectEqualSequence([1, 0, 1], buffer.map { Int($0) })

  expectEqual(2, uint8Ptr[count-1])
}
%   else: # !IsRaw
${SelfName}TestSuite.test("nonNilNonEmpty") {
  let count = 4
  let allocated = UnsafeMutablePointer<Float>.allocate(capacity: count)
  defer { allocated.deallocate() }
  allocated.initialize(repeating: 1.0, count: count)
  allocated[count - 1] = 2.0

  let buffer = ${SelfType}(start: ${PointerType}(allocated), count: count - 1)
  expectEqual(allocated, buffer.baseAddress)
  expectEqual(count - 1, buffer.count)
  expectEqual(count - 1, buffer.endIndex - buffer.startIndex)

  allocated[1] = 0.0
  expectEqual(1.0, buffer[0])
  expectEqual(0.0, buffer[1])
  expectEqual(1.0, buffer[2])

  var iter = buffer.makeIterator()
  expectEqual(1.0, iter.next())
  expectEqual(0.0, iter.next())
  expectEqual(1.0, iter.next())
  expectNil(iter.next())

  expectEqualSequence([1.0, 0.0, 1.0], buffer)

  expectEqual(2.0, allocated[count-1])
}
%   end # !IsRaw

${SelfName}TestSuite.test("badCount")
  .skip(.custom(
    { _isFastAssertConfiguration() },
    reason: "this trap is not guaranteed to happen in -Ounchecked"))
  .code {
  expectCrashLater()

  let emptyAllocated = UnsafeMutablePointer<Float>.allocate(capacity: 0)
  defer { emptyAllocated.deallocate() }

  let buffer = ${SelfType}(start: ${PointerType}(emptyAllocated), count: -1)
  _ = buffer
}

${SelfName}TestSuite.test("badNilCount")
  .skip(.custom(
    { _isFastAssertConfiguration() },
    reason: "this trap is not guaranteed to happen in -Ounchecked"))
  .code {
  expectCrashLater()

  let buffer = ${SelfType}(start: nil, count: 1)
  _ = buffer
}
% end # for SelfName, IsRaw, SelfType

UnsafeMutableRawBufferPointerTestSuite.test("changeElementViaBuffer") {
  let count = 4
  let allocated = UnsafeMutableRawPointer.allocate(byteCount: count, alignment: 1)
  defer { allocated.deallocate() }
  let uint8Ptr = allocated.initializeMemory(as: UInt8.self, repeating: 1, count: count)
  uint8Ptr[count-1] = UInt8.max

  var buffer = UnsafeMutableRawBufferPointer(start: allocated, count: count - 1)

  buffer[1] = 0
  expectEqual(1, buffer[0])
  expectEqual(0, buffer[1])
  expectEqual(1, buffer[2])

  expectEqual(1, uint8Ptr[0])
  expectEqual(0, uint8Ptr[1])
  expectEqual(1, uint8Ptr[2])
  expectEqual(UInt8.max, uint8Ptr[count-1])

  buffer.sort()
  expectEqual(0, buffer[0])
  expectEqual(1, buffer[1])
  expectEqual(1, buffer[2])

  expectEqual(0, uint8Ptr[0])
  expectEqual(1, uint8Ptr[1])
  expectEqual(1, uint8Ptr[2])
  expectEqual(UInt8.max, uint8Ptr[count-1])
}

UnsafeMutableBufferPointerTestSuite.test("changeElementViaBuffer") {
  let count = 4
  let allocated = UnsafeMutablePointer<Float>.allocate(capacity: count)
  defer { allocated.deallocate() }
  allocated.initialize(repeating: 1.0, count: count)
  allocated[count-1] = -1.0

  var buffer = UnsafeMutableBufferPointer(start: allocated, count: count - 1)

  buffer[1] = 0.0
  expectEqual(1.0, buffer[0])
  expectEqual(0.0, buffer[1])
  expectEqual(1.0, buffer[2])

  expectEqual(1.0, allocated[0])
  expectEqual(0.0, allocated[1])
  expectEqual(1.0, allocated[2])
  expectEqual(-1.0, allocated[count-1])

  buffer.sort()
  expectEqual(0.0, buffer[0])
  expectEqual(1.0, buffer[1])
  expectEqual(1.0, buffer[2])

  expectEqual(0.0, allocated[0])
  expectEqual(1.0, allocated[1])
  expectEqual(1.0, allocated[2])
  expectEqual(-1.0, allocated[count-1])
}

UnsafeMutableBufferPointerTestSuite.test("withContiguous(Mutable)StorageIfAvailable") {
  let count = 4
  let allocated = UnsafeMutablePointer<Int>.allocate(capacity: count)
  defer { allocated.deallocate() }
  allocated.initialize(repeating: 1, count: count)

  var mutableBuffer = UnsafeMutableBufferPointer(start: allocated, count: count)
  let executed: ()? = mutableBuffer.withContiguousMutableStorageIfAvailable { buf in
    for i in 0..<buf.count { buf[i] *= 2 }
  }
  expectNotNil(executed)
  let result1 = mutableBuffer.withContiguousStorageIfAvailable { buf in
    return buf.reduce(0, +)
  }
  expectEqual(count*2, result1)

  let immutableBuffer = UnsafeBufferPointer(start: allocated, count: count)
  let result2 = immutableBuffer.withContiguousStorageIfAvailable { buf in
    return buf.reduce(0, +)
  }
  expectEqual(result1, result2)
}

UnsafeMutableRawBufferPointerTestSuite.test("withContiguous(Mutable)StorageIfAvailable") {
  for c in [0, 1, 4] {
    let pointer = UnsafeMutableRawPointer.allocate(byteCount: c, alignment: c)
    defer { pointer.deallocate() }

    let mutableBuffer = UnsafeMutableRawBufferPointer(start: pointer, count: c)
    mutableBuffer.copyBytes(from: 0..<UInt8(c))

    let r: ()? = mutableBuffer.withContiguousMutableStorageIfAvailable {
      for i in $0.indices { $0[i] = 2*($0[i]+1) }
    }
    expectNotNil(r)
    let s = mutableBuffer.withContiguousStorageIfAvailable {
      $0.reduce(0, +)
    }
    expectEqual(s.map(Int.init), c*(c+1))

    let immutableBuffer = UnsafeRawBufferPointer(mutableBuffer)
    let t = immutableBuffer.withContiguousStorageIfAvailable {
      $0.reduce(0, +)
    }
    expectEqual(s, t)
  }
}

UnsafeMutableBufferPointerTestSuite.test("initialize(from: Slice)") {
  let o = 91
  let c = 1_000
  let a = Slice(base: Array(0..<c), bounds: o..<c)

  let buffer = UnsafeMutableBufferPointer<Int>.allocate(capacity: c-o)
  defer { buffer.deallocate() }

  var (iterator, copied) = buffer.initialize(from: a)
  expectEqual(iterator.next(), nil)
  expectEqual(copied, c-o)

  let t = buffer.indices.randomElement()!
  expectEqual(a[t+o], buffer[t])
}

UnsafeMutableBufferPointerTestSuite.test("Slice.withContiguousStorageIfAvailable") {
  guard #available(SwiftStdlib 5.3, *) else {
    return
  }

  for test in subscriptRangeTests {
    let c = test.collection.map { MinimalEquatableValue($0.value) }
    let buffer = UnsafeMutableBufferPointer<MinimalEquatableValue>.allocate(
      capacity: test.collection.count)
    defer { buffer.deallocate() }
    var (it, idx) = buffer.initialize(from: c)
    expectEqual(buffer.endIndex, idx)
    expectNil(it.next())

    let expected = test.expected.map { MinimalEquatableValue($0.value) }
    let r1: Void? = buffer[test.bounds].withContiguousStorageIfAvailable { b in
      expectTrue(expected.elementsEqual(b))
    }
    expectNotNil(r1)
    let r2: Void? = buffer[test.bounds].withContiguousMutableStorageIfAvailable { b in
      expectTrue(expected.elementsEqual(b))
    }
    expectNotNil(r2)
  }
}

UnsafeMutableRawBufferPointerTestSuite.test("Slice.withContiguousStorageIfAvailable") {
  for test in subscriptRangeTests {
    let c = test.collection.map({ UInt8($0.value/1000) })
    let buffer = UnsafeMutableRawBufferPointer.allocate(
      byteCount: test.collection.count, alignment: 8
    )
    defer { buffer.deallocate() }
    buffer.copyBytes(from: c)

    let expected = test.expected.map({ UInt8($0.value/1000) })
    let r1: ()? = buffer[test.bounds].withContiguousStorageIfAvailable {
      expectTrue(expected.elementsEqual($0))
    }
    expectNotNil(r1)
    let r2: ()? = buffer[test.bounds].withContiguousMutableStorageIfAvailable {
      for i in $0.indices { $0[i] += 1 }
    }
    expectNotNil(r2)
    expectTrue(buffer[test.bounds].elementsEqual(expected.map({ $0+1 })))
  }
}

UnsafeMutableBufferPointerTestSuite.test("sort") {
  var values = (0..<1000).map({ _ in Int.random(in: 0..<100) })
  let sortedValues = values.sorted()
  values.withUnsafeMutableBufferPointer { buffer in
    buffer.sort()
  }
  expectEqual(values, sortedValues)
}

UnsafeMutableBufferPointerTestSuite.test("partition") {
  var values = (0..<1000).map({ _ in Int.random(in: 0..<100) })
  let partitionIndex = values.withUnsafeMutableBufferPointer { buffer in
    return buffer.partition(by: { $0 % 2 == 0 })
  }
  expectTrue(values[..<partitionIndex].allSatisfy({ $0 % 2 != 0 }))
  expectTrue(values[partitionIndex...].allSatisfy({ $0 % 2 == 0 }))
}

let bufCount = 4
let sliceRange: Range = 1..<bufCount-1
% for mutable in [True, False]:
% for raw in [True, False]:
% for action in ['read', 'change']:
% if action != 'change' or mutable:
for testIndex in (0..<bufCount) {
% Type = 'Unsafe' + ('Mutable' if mutable else '') + ('Raw' if raw else '') + 'BufferPointer'
  ${Type}TestSuite.test("${action}Element\(testIndex)ViaSlice") {
% if raw:
    let allocated = UnsafeMutableRawPointer.allocate(byteCount: bufCount, alignment: 8)
    for i in 0..<bufCount {
      allocated.storeBytes(of: UInt8(i), toByteOffset: i, as: UInt8.self)
    }
% else:
    let allocated = UnsafeMutablePointer<Int>.allocate(capacity: bufCount)
    for i in 0..<bufCount { allocated[i] = i }
% end # if mutable
    defer { allocated.deallocate() }

    let buffer = ${Type}(start: allocated, count: bufCount)
    ${'var' if mutable and action != 'read' else 'let'} slice = buffer[sliceRange]

    if _isDebugAssertConfiguration(),
       testIndex < sliceRange.lowerBound ||
       testIndex >= sliceRange.upperBound {
      expectCrashLater()
    }
% if action == 'read':
    let value = slice[testIndex]
    expectEqual(buffer[testIndex], value)
% else:
    slice[testIndex] = 103
    expectEqual(buffer[testIndex], 103)
% end # if action
  }
}
% end # if action or mutable
% end # for action
% end # for raw
% end # for mutable

let testRanges = (0..<bufCount-1).map({ i -> Range<Int> in i..<i+2 })
% for mutable in [True, False]:
% for raw in [True, False]:
% for action in ['read', 'change']:
% if action != 'change' or mutable:
for testRange in testRanges {
% Type = 'Unsafe' + ('Mutable' if mutable else '') + ('Raw' if raw else '') + 'BufferPointer'
  ${Type}TestSuite.test("${action}Slice\(testRange)ViaSlice") {
% if raw:
    let allocated = UnsafeMutableRawPointer.allocate(byteCount: bufCount+2, alignment: 8)
    for i in 0..<bufCount+2 {
      allocated.storeBytes(of: UInt8(i), toByteOffset: i, as: UInt8.self)
    }
% else:
    let allocated = UnsafeMutablePointer<Int>.allocate(capacity: bufCount+2)
    for i in 0..<bufCount+2 { allocated[i] = i }
% end # if mutable
    defer { allocated.deallocate() }

    let buffer = ${Type}(start: allocated, count: bufCount+2)
    ${'var' if mutable and action != 'read' else 'let'} slice = buffer[sliceRange]

    if _isDebugAssertConfiguration(),
      testRange.lowerBound < sliceRange.lowerBound ||
      testRange.upperBound > sliceRange.upperBound {
      expectCrashLater()
    }

% if action == 'read':
    let value = slice[testRange]
    expectEqualSequence(buffer[testRange], value)
% else:
    let sourceSlice = buffer[bufCount..<bufCount+2]
    slice[testRange] = sourceSlice
    expectEqualSequence(buffer[testRange], sourceSlice)
% end # if action
  }
}
% end # if action or mutable
% end # for action
% end # for raw
% end # for mutable

protocol SubscriptTest {
  static var start: Int { get }
  static var end: Int { get }
  static var elementCount: Int { get }
}

// Initialize memory with opaque values, for use with subscript tests.
extension SubscriptTest {
  static var elementCount: Int { get { return end - start } }

% for SelfType in ['UnsafeRawBufferPointer', 'UnsafeMutableRawBufferPointer']:
  /// Create and populate an `${SelfType}` for use with unit tests.
  /// PRECONDITION: `memory` must be allocated with space for
  /// `SubscriptGetTest.elementCount` bytes.
  static func create${SelfType}(from memory: UnsafeMutableRawPointer)
    -> ${SelfType}
  {
    for i in Self.start..<Self.end {
      (memory + i * MemoryLayout<UInt8>.stride).initializeMemory(as: UInt8.self, repeating: numericCast(i), count: 1)
    }
    return ${SelfType}(start: memory, count: Self.elementCount)
  }
% end

% for SelfType in ['UnsafeBufferPointer', 'UnsafeMutableBufferPointer']:
  /// Create and populate an `${SelfType}` for use with unit tests.
  /// PRECONDITION: `memory` must be allocated with space for
  /// `SubscriptGetTest.elementCount` elements.
  static func create${SelfType}(from memory: UnsafeMutablePointer<OpaqueValue<Int>>)
    -> ${SelfType}<OpaqueValue<Int>>
  {
    for i in Self.start..<Self.end {
      memory[i] = OpaqueValue(i)
    }
    return ${SelfType}(start: memory, count: Self.elementCount)
  }
% end
}

struct SubscriptGetTest : SubscriptTest {
  // SubscriptGetTest operates on a `(end - start)` sized buffer containing
  // monotonically increasing integers from `start` to `end - 1`.
  static var start = 0
  static var end = 20

  let rangeSelection: RangeSelection
  /// The values that should be expected by slicing the UBP, or `nil` if the
  /// test is expected to crash.
  let expectedValues: [Int]?
  /// Same as `expectedValues`, but for closed ranges. `nil` if no difference,
  /// and empty if the test is expected to crash.
  let expectedClosedValues: [Int]?

  let loc: SourceLoc

  init(
    rangeSelection: RangeSelection, expectedValues: [Int]? = nil,
    expectedClosedValues: [Int]? = nil,
    file: String = #file, line: UInt = #line
  ) {
    self.rangeSelection = rangeSelection
    self.expectedValues = expectedValues
    self.expectedClosedValues = expectedClosedValues ?? expectedValues
    self.loc = SourceLoc(file, line, comment: "test data")
  }
}

let subscriptGetTests : [SubscriptGetTest] = [
  // Valid, empty.
  SubscriptGetTest(rangeSelection: .emptyRange, expectedValues: []),

  // Valid, edges.
  SubscriptGetTest(rangeSelection: .leftEdge,
    expectedValues: [],
    expectedClosedValues: [0]),
  SubscriptGetTest(rangeSelection: .rightEdge,
    expectedValues: [],
    expectedClosedValues: [19]),

  // Valid, internal.
  SubscriptGetTest(rangeSelection: .leftHalf,
    expectedValues: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]),
  SubscriptGetTest(rangeSelection: .rightHalf,
    expectedValues: [10, 11, 12, 13, 14, 15, 16, 17, 18, 19]),
  SubscriptGetTest(rangeSelection: .middle,
    expectedValues: [5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]),
  SubscriptGetTest(rangeSelection: .full,
    expectedValues: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]),
  SubscriptGetTest(rangeSelection: .offsets(2, 4),
    expectedValues: [2, 3],
    expectedClosedValues: [2, 3, 4]),
  SubscriptGetTest(rangeSelection: .offsets(16, 19),
    expectedValues: [16, 17, 18],
    expectedClosedValues: [16, 17, 18, 19]),

  // Invalid, bottom out of bounds.
  SubscriptGetTest(rangeSelection: .offsets(-1, -1)),
  SubscriptGetTest(rangeSelection: .offsets(-1, 0)),
  SubscriptGetTest(rangeSelection: .offsets(-100, 5)),

  // Invalid, top out of bounds.
  SubscriptGetTest(rangeSelection: .offsets(20, 20),
    expectedValues: []), // Only crash on a closed range.
  SubscriptGetTest(rangeSelection: .offsets(19, 20),
    expectedValues: [19],
    expectedClosedValues: []), // Only crash on a closed range
  SubscriptGetTest(rangeSelection: .offsets(21, 21)),
  SubscriptGetTest(rangeSelection: .offsets(5, 100)),

  // Invalid, both out of bounds.
  SubscriptGetTest(rangeSelection: .offsets(-1, 20)),
  SubscriptGetTest(rangeSelection: .offsets(-100, 100)),
]

struct SubscriptSetTest : SubscriptTest {
  // SubscriptSetTest operates on a `(end - start)` sized buffer containing
  // monotonically increasing integers from `start` to `end - 1`.
  static var start = 0
  static var end = 10

  let rangeSelection: RangeSelection

  let replacementValues: [OpaqueValue<Int>]
  let replacementClosedValues: [OpaqueValue<Int>]

  /// The values that should be expected by slicing the UBP, or `nil` if the
  /// test is expected to crash.
  let expectedValues: [Int]?
  /// Same as `expectedValues`, but for closed ranges. `nil` if no difference.
  let expectedClosedValues: [Int]?

  let loc: SourceLoc

  init(
    rangeSelection: RangeSelection,
    replacementValues: [Int],
    replacementClosedValues: [Int]? = nil,
    expectedValues: [Int]? = nil,
    expectedClosedValues: [Int]? = nil,
    file: String = #file, line: UInt = #line
  ) {
    self.rangeSelection = rangeSelection
    self.expectedValues = expectedValues
    self.expectedClosedValues = expectedClosedValues ?? expectedValues

    self.replacementValues = replacementValues.map { OpaqueValue($0) }
    if let replacements = replacementClosedValues {
      self.replacementClosedValues = replacements.map { OpaqueValue($0) }
    } else {
      self.replacementClosedValues = self.replacementValues
    }
    self.loc = SourceLoc(file, line, comment: "test data")
  }

  /// Create and populate an UnsafeMutableRawBufferPointer slice for use with
  /// unit tests.
  /// PRECONDITION: `memory` must be allocated with space for
  /// `replacementValues.count` bytes.
  func replacementValuesSlice(
    from memory: UnsafeMutableRawPointer,
    replacementValues: [OpaqueValue<Int>]
  ) -> UnsafeMutableRawBufferPointer.SubSequence
  {
    for (i, value) in replacementValues.enumerated() {
      (memory + i * MemoryLayout<UInt8>.stride).initializeMemory(
        as: UInt8.self, repeating: numericCast(value.value), count: 1)
    }
    let buffer = UnsafeMutableRawBufferPointer(
      start: memory, count: replacementValues.count)
    let fullRange = RangeSelection.full.range(in: buffer)
    return buffer[fullRange]
  }

  /// Create and populate an UnsafeMutableBufferPointer slice for use with unit
  /// tests.
  /// PRECONDITION: `memory` must be allocated with space for
  /// `replacementValues.count` elements.
  func replacementValuesSlice(
    from memory: UnsafeMutablePointer<OpaqueValue<Int>>,
    replacementValues: [OpaqueValue<Int>]
  ) -> Slice<UnsafeMutableBufferPointer<OpaqueValue<Int>>>
  {
    for (i, value) in replacementValues.enumerated() {
      memory[i] = value
    }
    let buffer = UnsafeMutableBufferPointer(
      start: memory, count: replacementValues.count)
    let fullRange = RangeSelection.full.range(in: buffer)
    return buffer[fullRange]
  }
}

let subscriptSetTests : [SubscriptSetTest] = [
  // Valid, empty.
  SubscriptSetTest(
    rangeSelection: .emptyRange,
    replacementValues: [],
    expectedValues: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]),

  // Valid, edges.
  SubscriptSetTest(
    rangeSelection: .leftEdge,
    replacementValues: [],
    replacementClosedValues: [91],
    expectedValues: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
    expectedClosedValues: [91, 1, 2, 3, 4, 5, 6, 7, 8, 9]),
  SubscriptSetTest(
    rangeSelection: .rightEdge,
    replacementValues: [],
    replacementClosedValues: [91],
    expectedValues: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
    expectedClosedValues: [0, 1, 2, 3, 4, 5, 6, 7, 8, 91]),

  // Valid, internal.
  SubscriptSetTest(
    rangeSelection: .leftHalf,
    replacementValues: [10, 11, 12, 13, 14],
    expectedValues: [10, 11, 12, 13, 14, 5, 6, 7, 8, 9]),
  SubscriptSetTest(
    rangeSelection: .rightHalf,
    replacementValues: [10, 11, 12, 13, 14],
    expectedValues: [0, 1, 2, 3, 4, 10, 11, 12, 13, 14]),
  SubscriptSetTest(
    rangeSelection: .middle,
    replacementValues: [10, 11, 12, 13, 14, 15],
    expectedValues: [0, 1, 10, 11, 12, 13, 14, 15, 8, 9]),
  SubscriptSetTest(
    rangeSelection: .full,
    replacementValues: [10, 11, 12, 13, 14, 15, 16, 17, 18, 19],
    expectedValues: [10, 11, 12, 13, 14, 15, 16, 17, 18, 19]),

  // Invalid, range and replacement count mismatch.
  SubscriptSetTest(
    rangeSelection: .leftEdge,
    replacementValues: [9, 9],
    replacementClosedValues: [9, 9, 9]),
  SubscriptSetTest(
    rangeSelection: .offsets(1, 2),
    replacementValues: [],
    replacementClosedValues: [9]),
  SubscriptSetTest(
    rangeSelection: .offsets(1, 2),
    replacementValues: [9, 9],
    replacementClosedValues: [9, 9, 9]),
  SubscriptSetTest(
    rangeSelection: .offsets(2, 5),
    replacementValues: [9, 9],
    replacementClosedValues: [9, 9, 9]),
  SubscriptSetTest(
    rangeSelection: .offsets(2, 5),
    replacementValues: [9, 9, 9, 9],
    replacementClosedValues: [9, 9, 9, 9, 9]),

  // Invalid, bottom out of bounds.
  SubscriptSetTest(
    rangeSelection: .offsets(-1, -1),
    replacementValues: []),
  SubscriptSetTest(
    rangeSelection: .offsets(-1, 0),
    replacementValues: [9]),
  SubscriptSetTest(
    rangeSelection: .offsets(-3, 5),
    replacementValues: [9, 9, 9, 9, 9, 9, 9, 9]),

  // Invalid, top out of bounds.
  SubscriptSetTest(
    rangeSelection: .offsets(10, 10),
    replacementValues: [],
    expectedValues: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
    expectedClosedValues: []), // Only crash on a closed range.
  SubscriptSetTest(
    rangeSelection: .offsets(9, 10),
    replacementValues: [91],
    expectedValues: [0, 1, 2, 3, 4, 5, 6, 7, 8, 91],
    expectedClosedValues: []), // Only crash on a closed range.
  SubscriptSetTest(
    rangeSelection: .offsets(11, 11),
    replacementValues: []),
  SubscriptSetTest(
    rangeSelection: .offsets(8, 15),
    replacementValues: [9, 9, 9, 9, 9, 9, 9]),

  // Invalid, both out of bounds.
  SubscriptSetTest(
    rangeSelection: .offsets(-1, 10),
    replacementValues: [9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9]),
  SubscriptSetTest(
    rangeSelection: .offsets(-2, 11),
    replacementValues: [9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9]),
]

% for (SelfName, IsRaw) in [
%   ('UnsafeBufferPointer', False),
%   ('UnsafeRawBufferPointer', True),
%   ('UnsafeMutableBufferPointer', False),
%   ('UnsafeMutableRawBufferPointer', True)
% ]:

%   Raw = 'Raw' if IsRaw else ''

%   for RangeName in ['range', 'closedRange']:
${SelfName}TestSuite.test("subscript/${RangeName}/get").forEach(in: subscriptGetTests) {
  (test) in

  let expectedValues: [Int]?
%     if 'closed' in RangeName.lower():
  if test.rangeSelection.isEmpty {
    return
  }
  // Treat an empty set as nil for closed ranges.
  if test.expectedClosedValues?.isEmpty ?? true {
    expectedValues = nil
  }
  else {
    expectedValues = test.expectedClosedValues
  }
%     else:
  expectedValues = test.expectedValues
%     end

  let elementCount = SubscriptGetTest.elementCount

%     if IsRaw:
  var memory: UnsafeMutableRawPointer
%     else:
  var memory: UnsafeMutablePointer<OpaqueValue<Int>>
%     end

  memory = allocateFor${Raw}Buffer(count: elementCount)
  defer { deallocateFor${Raw}Buffer(memory, count: elementCount) }

  let buffer = SubscriptGetTest.create${SelfName}(from: memory)

%     if IsRaw:
  // A raw buffer pointer has debug bounds checks on indices, and
  // (currently) invokes Collection._failEarlyRangeCheck in nondebug mode.
  if expectedValues == nil { expectCrashLater() }
%     end
  let range = test.rangeSelection.${RangeName}(in: buffer)

  if _isDebugAssertConfiguration() {
    if expectedValues == nil { expectCrashLater() }
  }
  let slice = buffer[range]
  // If expectedValues is nil, we should have crashed above. Allowing the
  // following code to crash leads to false positives.
  if let expectedValues = expectedValues {
    expectEqual(
      expectedValues,
%     if IsRaw:
      slice.map { Int($0) },
% else:
      slice.map { $0.value },
%     end
      stackTrace: SourceLocStack().with(test.loc)
    )
  }
}

%   end # RangeName
% end # SelfName, IsMutable, IsRaw, SelfType, PointerType

% for (SelfName, IsRaw) in [
%   ('UnsafeMutableBufferPointer', False),
%   ('UnsafeMutableRawBufferPointer', True)
% ]:
%   Raw = 'Raw' if IsRaw else ''
%   for RangeName in ['range', 'closedRange']:

UnsafeMutable${'Raw' if IsRaw else ''}BufferPointerTestSuite.test("subscript/${RangeName}/set")
%     if not IsRaw:
  // UnsafeRawBuffer (currently) invokes Collection._failEarlyRangeCheck
  // in nondebug mode.
  .skip(.custom(
    { !_isDebugAssertConfiguration() },
    reason: "This tests a debug precondition."))
%     end
.forEach(in: subscriptSetTests) { (test) in

  let expectedValues: [Int]?
  let replacementValues: [OpaqueValue<Int>]
  let elementCount = SubscriptSetTest.elementCount

%      if 'closed' in RangeName.lower():
  if test.rangeSelection.isEmpty {
    return
  }
  // Treat an empty set as nil for closed ranges.
  if test.expectedClosedValues?.isEmpty ?? true {
    expectedValues = nil
  }
  else {
    expectedValues = test.expectedClosedValues
  }
  replacementValues = test.replacementClosedValues
  let isOutOfBounds: () -> Bool = {
    switch test.rangeSelection {
    case let .offsets(lowerBound, upperBound):
      return lowerBound < 0 || upperBound >= elementCount
    default:
      return false
    }
  }
%      else: # !closed
  expectedValues = test.expectedValues
  replacementValues = test.replacementValues
  let isOutOfBounds: () -> Bool = {
    switch test.rangeSelection {
    case let .offsets(lowerBound, upperBound):
      return lowerBound < 0 || upperBound > elementCount
    default:
      return false
    }
  }
%      end # !closed

%     if IsRaw:
  var memory: UnsafeMutableRawPointer
  var sliceMemory: UnsafeMutableRawPointer
%     else:
  var memory: UnsafeMutablePointer<OpaqueValue<Int>>
  var sliceMemory: UnsafeMutablePointer<OpaqueValue<Int>>
%     end

  memory = allocateFor${Raw}Buffer(count: elementCount)
  defer { deallocateFor${Raw}Buffer(memory, count: elementCount) }

  sliceMemory = allocateFor${Raw}Buffer(count: replacementValues.count)
  defer { deallocateFor${Raw}Buffer(
      sliceMemory, count: replacementValues.count) }

% if RangeName == 'range':
  let buffer = SubscriptSetTest.create${SelfName}(from: memory)
% else:
  var buffer = SubscriptSetTest.create${SelfName}(from: memory)
% end

%     if IsRaw:
  // A raw buffer pointer has debug bounds checks on indices, and
  // (currently) invokes Collection._failEarlyRangeCheck in nondebug mode.
  if _isDebugAssertConfiguration() || isOutOfBounds() {
    if expectedValues == nil { expectCrashLater() }
  }
%     else:
  _ = isOutOfBounds
%     end
  let range = test.rangeSelection.${RangeName}(in: buffer)

  let replacementSlice = test.replacementValuesSlice(
    from: sliceMemory,
    replacementValues: replacementValues)

  if _isDebugAssertConfiguration() {
    if expectedValues == nil { expectCrashLater() }
  }
  buffer[range] = replacementSlice
  // If expectedValues is nil, we should have crashed above. Allowing the
  // following code to crash leads to false positives.
  if let expectedValues = expectedValues {
    expectEqual(
      expectedValues,
%     if IsRaw:
      buffer.map { Int($0) },
% else:
      buffer.map { $0.value },
%     end
      stackTrace: SourceLocStack().with(test.loc)
    )
  }
}

%   end # RangeName

UnsafeMutable${'Raw' if IsRaw else ''}BufferPointerTestSuite.test("subscript/set/overlaps") {
% if IsRaw:
  let buffer = UnsafeMutableRawBufferPointer.allocate(byteCount: 4, alignment: 1)
% else:
  let buffer = UnsafeMutableBufferPointer<Int>.allocate(capacity: 4)
% end
  defer { buffer.deallocate() }

  // Right Overlap
  buffer[0] = 1
  buffer[1] = 2
  buffer[1..<3] = buffer[0..<2]
  expectEqual(1, buffer[1])
  expectEqual(2, buffer[2])
  // Left Overlap
  buffer[1] = 2
  buffer[2] = 3
  buffer[0..<2] = buffer[1..<3]
  expectEqual(2, buffer[0])
  expectEqual(3, buffer[1])
  // Disjoint
  buffer[2] = 2
  buffer[3] = 3
  buffer[0..<2] = buffer[2..<4]
  expectEqual(2, buffer[0])
  expectEqual(3, buffer[1])
  buffer[0] = 0
  buffer[1] = 1
  buffer[2..<4] = buffer[0..<2]
  expectEqual(0, buffer[2])
  expectEqual(1, buffer[3])
}

UnsafeMutable${'Raw' if IsRaw else ''}BufferPointerTestSuite.test("nonmutating-swapAt") {
% if IsRaw:
  let allocated = UnsafeMutableRawPointer.allocate(byteCount: 4, alignment: 8)
  let buffer = UnsafeMutableRawBufferPointer(start: allocated, count: 3)
  allocated.storeBytes(of: UInt8.max, toByteOffset: 3, as: UInt8.self)
% else:
  let allocated = UnsafeMutablePointer<Int>.allocate(capacity: 4)
  let buffer = UnsafeMutableBufferPointer(start: allocated, count: 3)
  allocated[3] = Int.max
% end
  defer { allocated.deallocate() }

  buffer[0] = 0
  buffer[1] = 1
  buffer[2] = 2

  buffer.swapAt(0, 0)
  expectEqual(Array(buffer), [0, 1, 2])

  buffer.swapAt(0, 2)
  expectEqual(Array(buffer), [2, 1, 0])

  if _isDebugAssertConfiguration() {
    expectCrashLater()
  }
  buffer.swapAt(2, 3)
}

% if not IsRaw:
UnsafeMutableBufferPointerTestSuite.test("nonmutating-swapAt-withARC") {
  let buffer = UnsafeMutableBufferPointer<String>.allocate(capacity: 3)
  defer { buffer.deallocate() }

  _ = buffer.initialize(from: (0..<3).map(String.init(describing:)))

  buffer.swapAt(0, 0)
  expectEqual(Array(buffer), ["0", "1", "2"])

  buffer.swapAt(0, 2)
  expectEqual(Array(buffer), ["2", "1", "0"])
}
% end

% end # SelfName

% for mutable in [True, False]:
% TypedName = 'UnsafeMutableBufferPointer' if mutable else 'UnsafeBufferPointer'
Unsafe${'Mutable' if mutable else ''}BufferPointerTestSuite.test("withMemoryRebound") {
  // test withMemoryRebound behaviour, post SE-0333.
  let mutableBufferI = UnsafeMutableBufferPointer<Int>.allocate(capacity: 4)
  defer { mutableBufferI.deallocate() }
  let ptrI = ${'mutableBufferI' if mutable else TypedName + '(mutableBufferI)'}
  // test rebinding to a wider type with the same alignment
  ptrI.withMemoryRebound(to: (Int, Int).self) {
    // Make sure the closure argument is a ${TypedName}
    let ptrT: ${TypedName}<(Int, Int)> = $0
    expectEqual(ptrT.count, 2)
    // and that the element type is (Int, Int).
    let mutablePtrT = ${'ptrT' if mutable else 'UnsafeMutableBufferPointer(mutating: ptrT)'}
    expectType((Int, Int).self, &mutablePtrT[0])
    // test rebinding to a narrower type
    ptrT.withMemoryRebound(to: UInt.self) {
      // Make sure the closure argument is a ${TypedName}
      let ptrU: ${TypedName}<UInt> = $0
      expectEqual(ptrU.count, 4)
      // and that the element type is UInt.
      let mutablePtrU = ${'ptrU' if mutable else 'UnsafeMutableBufferPointer(mutating: ptrU)'}
      expectType(UInt.self, &mutablePtrU[0])
    }
  }
}

% RawName = 'UnsafeMutableRawBufferPointer' if mutable else 'UnsafeRawBufferPointer'
Unsafe${'Mutable' if mutable else ''}RawBufferPointerTestSuite.test("withMemoryRebound") {
  // test withMemoryRebound behaviour, post SE-0333.
  let allocated = UnsafeMutableRawBufferPointer.allocate(byteCount: 32,  alignment: 8)
  defer { allocated.deallocate() }
  let ptrR = ${'allocated' if mutable else RawName + '(allocated)'}
  ptrR.withMemoryRebound(to: Int.self) {
    // Make sure the closure argument is a ${TypedName}
    let ptrT: ${TypedName}<Int> = $0
    expectEqual(ptrT.count, 32/MemoryLayout<Int>.stride)
    // and that the element type is `Int`.
    let mutablePtrT = ${'ptrT' if mutable else 'UnsafeMutableBufferPointer(mutating: ptrT)'}
    expectType(Int.self, &mutablePtrT[0])
  }
}

% end # mutable

UnsafeRawBufferPointerTestSuite.test("assumingMemoryBound") {
  let array = (0..<4).map({ $0 })
  array.withUnsafeBytes({
    let b: UnsafeBufferPointer = $0.assumingMemoryBound(to: Int.self)
    expectEqual(b.count, array.count)
    expectEqual(b[3], array[3])
  })
  var mutableArray = array
  mutableArray.withUnsafeMutableBytes({
    let b: UnsafeMutableBufferPointer = $0.assumingMemoryBound(to: Int.self)
    expectEqual(b.count, array.count)
    for i in b.indices { b[i] += 1 }
  })
  expectEqual(mutableArray[3], array[3]+1)
}

runAllTests()