// Copyright 2019 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include 'src/builtins/builtins-constructor-gen.h'

namespace typed_array_createtypedarray {
  extern builtin IterableToListMayPreserveHoles(Context, Object, Callable):
      JSArray;

  extern macro TypedArrayBuiltinsAssembler::AllocateEmptyOnHeapBuffer(
      implicit context: Context)(uintptr): JSArrayBuffer;
  extern macro CodeStubAssembler::AllocateByteArray(uintptr): ByteArray;
  extern macro TypedArrayBuiltinsAssembler::GetDefaultConstructor(
      implicit context: Context)(JSTypedArray): JSFunction;
  extern macro TypedArrayBuiltinsAssembler::IsSharedArrayBuffer(JSArrayBuffer):
      bool;
  extern macro TypedArrayBuiltinsAssembler::SetupTypedArrayEmbedderFields(
      JSTypedArray): void;

  extern runtime ThrowInvalidTypedArrayAlignment(implicit context: Context)(
      Map, String): never;
  extern runtime TypedArrayCopyElements(Context, JSTypedArray, Object, Number):
      void;

  transitioning macro AllocateTypedArray(implicit context: Context)(
      isOnHeap: constexpr bool, map: Map, buffer: JSArrayBuffer,
      byteOffset: uintptr, byteLength: uintptr, length: uintptr): JSTypedArray {
    let elements: ByteArray;
    let externalPointer: RawPtr;
    let basePointer: ByteArray | Smi;
    if constexpr (isOnHeap) {
      elements = AllocateByteArray(byteLength);
      basePointer = elements;
      externalPointer = PointerConstant(kExternalPointerForOnHeapArray);
    } else {
      basePointer = Convert<Smi>(0);

      // The max byteOffset is 8 * MaxSmi on the particular platform. 32 bit
      // platforms are self-limiting, because we can't allocate an array bigger
      // than our 32-bit arithmetic range anyway. 64 bit platforms could
      // theoretically have an offset up to 2^35 - 1.
      const backingStore: RawPtr = buffer.backing_store;
      externalPointer = backingStore + Convert<intptr>(byteOffset);

      // Assert no overflow has occurred. Only assert if the mock array buffer
      // allocator is NOT used. When the mock array buffer is used, impossibly
      // large allocations are allowed that would erroneously cause an overflow
      // and this assertion to fail.
      assert(
          IsMockArrayBufferAllocatorFlag() ||
          Convert<uintptr>(externalPointer) >= Convert<uintptr>(backingStore));

      elements = kEmptyByteArray;
    }

    // We can't just build the new object with "new JSTypedArray" here because
    // Torque doesn't know its full size including embedder fields, so use CSA
    // for the allocation step.
    const typedArray =
        UnsafeCast<JSTypedArray>(AllocateFastOrSlowJSObjectFromMap(map));
    typedArray.elements = elements;
    typedArray.buffer = buffer;
    typedArray.byte_offset = byteOffset;
    typedArray.byte_length = byteLength;
    typedArray.length = length;
    typedArray.external_pointer = externalPointer;
    typedArray.base_pointer = basePointer;
    SetupTypedArrayEmbedderFields(typedArray);
    return typedArray;
  }

  transitioning macro TypedArrayInitialize(implicit context: Context)(
      initialize: constexpr bool, map: Map, length: PositiveSmi,
      elementsInfo: typed_array::TypedArrayElementsInfo,
      bufferConstructor: JSReceiver): JSTypedArray {
    const byteLength = elementsInfo.CalculateByteLength(length)
        otherwise ThrowRangeError(kInvalidArrayBufferLength);
    const byteLengthNum = Convert<Number>(byteLength);
    const defaultConstructor = GetArrayBufferFunction();
    const byteOffset: uintptr = 0;

    try {
      if (bufferConstructor != defaultConstructor) {
        goto AttachOffHeapBuffer(ConstructWithTarget(
            defaultConstructor, bufferConstructor, byteLengthNum));
      }

      if (byteLength > kMaxTypedArrayInHeap) goto AllocateOffHeap;

      const buffer = AllocateEmptyOnHeapBuffer(byteLength);

      const isOnHeap: constexpr bool = true;
      const typedArray = AllocateTypedArray(
          isOnHeap, map, buffer, byteOffset, byteLength,
          Convert<uintptr>(length));

      if constexpr (initialize) {
        const backingStore = typedArray.data_ptr;
        typed_array::CallCMemset(backingStore, 0, byteLength);
      }

      return typedArray;
    }
    label AllocateOffHeap {
      if constexpr (initialize) {
        goto AttachOffHeapBuffer(Construct(defaultConstructor, byteLengthNum));
      } else {
        goto AttachOffHeapBuffer(Call(
            context, GetArrayBufferNoInitFunction(), Undefined, byteLengthNum));
      }
    }
    label AttachOffHeapBuffer(bufferObj: Object) {
      const buffer = Cast<JSArrayBuffer>(bufferObj) otherwise unreachable;
      const isOnHeap: constexpr bool = false;
      return AllocateTypedArray(
          isOnHeap, map, buffer, byteOffset, byteLength,
          Convert<uintptr>(length));
    }
  }

  // 22.2.4.2 TypedArray ( length )
  // ES #sec-typedarray-length
  transitioning macro ConstructByLength(implicit context: Context)(
      map: Map, length: JSAny,
      elementsInfo: typed_array::TypedArrayElementsInfo): JSTypedArray {
    const convertedLength: Number =
        ToInteger_Inline(context, length, kTruncateMinusZero);
    // The maximum length of a TypedArray is MaxSmi().
    // Note: this is not per spec, but rather a constraint of our current
    // representation (which uses Smis).
    // TODO(7881): support larger-than-smi typed array lengths
    const positiveLength: PositiveSmi = Cast<PositiveSmi>(convertedLength)
        otherwise ThrowRangeError(kInvalidTypedArrayLength, length);
    const defaultConstructor: Constructor = GetArrayBufferFunction();
    const initialize: constexpr bool = true;
    return TypedArrayInitialize(
        initialize, map, positiveLength, elementsInfo, defaultConstructor);
  }

  // 22.2.4.4 TypedArray ( object )
  // ES #sec-typedarray-object
  transitioning macro ConstructByArrayLike(implicit context: Context)(
      map: Map, arrayLike: HeapObject, initialLength: JSAny,
      elementsInfo: typed_array::TypedArrayElementsInfo,
      bufferConstructor: JSReceiver): JSTypedArray {
    // The caller has looked up length on arrayLike, which is observable.
    const length: PositiveSmi = ToSmiLength(initialLength)
        otherwise ThrowRangeError(kInvalidTypedArrayLength, initialLength);
    const initialize: constexpr bool = false;
    const typedArray = TypedArrayInitialize(
        initialize, map, length, elementsInfo, bufferConstructor);

    try {
      const src: JSTypedArray = Cast<JSTypedArray>(arrayLike) otherwise IfSlow;

      if (IsDetachedBuffer(src.buffer)) {
        ThrowTypeError(kDetachedOperation, 'Construct');

      } else if (src.elements_kind != elementsInfo.kind) {
        goto IfSlow;

      } else if (length > 0) {
        const byteLength = typedArray.byte_length;
        assert(byteLength <= kArrayBufferMaxByteLength);
        typed_array::CallCMemcpy(typedArray.data_ptr, src.data_ptr, byteLength);
      }
    }
    label IfSlow deferred {
      if (length > 0) {
        TypedArrayCopyElements(context, typedArray, arrayLike, length);
      }
    }
    return typedArray;
  }

  // 22.2.4.4 TypedArray ( object )
  // ES #sec-typedarray-object
  transitioning macro ConstructByIterable(implicit context: Context)(
      iterable: JSReceiver, iteratorFn: Callable): never
      labels IfConstructByArrayLike(JSArray, Number, JSReceiver) {
    const array: JSArray =
        IterableToListMayPreserveHoles(context, iterable, iteratorFn);
    goto IfConstructByArrayLike(array, array.length, GetArrayBufferFunction());
  }

  // 22.2.4.3 TypedArray ( typedArray )
  // ES #sec-typedarray-typedarray
  transitioning macro ConstructByTypedArray(implicit context: Context)(
      srcTypedArray: JSTypedArray): never
      labels IfConstructByArrayLike(JSTypedArray, Number, JSReceiver) {
    let bufferConstructor: JSReceiver = GetArrayBufferFunction();
    const srcBuffer: JSArrayBuffer = srcTypedArray.buffer;
    // TODO(petermarshall): Throw on detached typedArray.
    // TODO(v8:4156): Update this to support huge TypedArrays.
    let length =
        IsDetachedBuffer(srcBuffer) ? 0 : Convert<Number>(srcTypedArray.length);

    // The spec requires that constructing a typed array using a SAB-backed
    // typed array use the ArrayBuffer constructor, not the species constructor.
    // See https://tc39.github.io/ecma262/#sec-typedarray-typedarray.
    if (!IsSharedArrayBuffer(srcBuffer)) {
      bufferConstructor = SpeciesConstructor(srcBuffer, bufferConstructor);
      // TODO(petermarshall): Throw on detached typedArray.
      if (IsDetachedBuffer(srcBuffer)) length = 0;
    }
    goto IfConstructByArrayLike(srcTypedArray, length, bufferConstructor);
  }

  // 22.2.4.5 TypedArray ( buffer, byteOffset, length )
  // ES #sec-typedarray-buffer-byteoffset-length
  transitioning macro ConstructByArrayBuffer(implicit context: Context)(
      map: Map, buffer: JSArrayBuffer, byteOffset: JSAny, length: JSAny,
      elementsInfo: typed_array::TypedArrayElementsInfo): JSTypedArray {
    try {
      let offset: uintptr = 0;
      if (byteOffset != Undefined) {
        // 6. Let offset be ? ToIndex(byteOffset).
        offset = TryNumberToUintPtr(
            ToInteger_Inline(context, byteOffset, kTruncateMinusZero))
            otherwise goto IfInvalidOffset;

        // 7. If offset modulo elementSize ≠ 0, throw a RangeError exception.
        if (elementsInfo.IsUnaligned(offset)) {
          goto IfInvalidAlignment('start offset');
        }
      }

      let newLength: PositiveSmi = 0;
      let newByteLength: uintptr;
      // 8. If length is present and length is not undefined, then
      if (length != Undefined) {
        // a. Let newLength be ? ToIndex(length).
        newLength = ToSmiIndex(length) otherwise IfInvalidLength;
      }

      // 9. If IsDetachedBuffer(buffer) is true, throw a TypeError exception.
      if (IsDetachedBuffer(buffer)) {
        ThrowTypeError(kDetachedOperation, 'Construct');
      }

      // 10. Let bufferByteLength be buffer.[[ArrayBufferByteLength]].
      const bufferByteLength: uintptr = buffer.byte_length;

      // 11. If length is either not present or undefined, then
      if (length == Undefined) {
        // a. If bufferByteLength modulo elementSize ≠ 0, throw a RangeError
        // exception.
        if (elementsInfo.IsUnaligned(bufferByteLength)) {
          goto IfInvalidAlignment('byte length');
        }

        // b. Let newByteLength be bufferByteLength - offset.
        // c. If newByteLength < 0, throw a RangeError exception.
        if (bufferByteLength < offset) goto IfInvalidOffset;

        // Spec step 16 length calculated here to avoid recalculating the length
        // in the step 12 branch.
        newByteLength = bufferByteLength - offset;
        newLength = elementsInfo.CalculateLength(newByteLength)
            otherwise IfInvalidOffset;

        // 12. Else,
      } else {
        // a. Let newByteLength be newLength × elementSize.
        newByteLength = elementsInfo.CalculateByteLength(newLength)
            otherwise IfInvalidByteLength;

        // b. If offset + newByteLength > bufferByteLength, throw a RangeError
        // exception.
        if ((bufferByteLength < newByteLength) ||
            (offset > bufferByteLength - newByteLength))
          goto IfInvalidLength;
      }

      const isOnHeap: constexpr bool = false;
      return AllocateTypedArray(
          isOnHeap, map, buffer, offset, newByteLength,
          Convert<uintptr>(newLength));
    }
    label IfInvalidAlignment(problemString: String) deferred {
      ThrowInvalidTypedArrayAlignment(map, problemString);
    }
    label IfInvalidByteLength deferred {
      ThrowRangeError(kInvalidArrayBufferLength);
    }
    label IfInvalidLength deferred {
      ThrowRangeError(kInvalidTypedArrayLength, length);
    }
    label IfInvalidOffset deferred {
      ThrowRangeError(kInvalidOffset, byteOffset);
    }
  }

  transitioning macro ConstructByJSReceiver(implicit context:
                                                Context)(obj: JSReceiver): never
      labels IfConstructByArrayLike(JSReceiver, Number, JSReceiver) {
    try {
      const iteratorMethod: Object =
          GetIteratorMethod(obj) otherwise IfIteratorUndefined;
      const iteratorFn: Callable = Cast<Callable>(iteratorMethod)
          otherwise ThrowTypeError(kIteratorSymbolNonCallable);
      ConstructByIterable(obj, iteratorFn)
          otherwise IfConstructByArrayLike;
    }
    label IfIteratorUndefined {
      const lengthObj: JSAny = GetProperty(obj, kLengthString);
      const length: Smi = ToSmiLength(lengthObj)
          otherwise goto IfInvalidLength(lengthObj);
      goto IfConstructByArrayLike(obj, length, GetArrayBufferFunction());
    }
    label IfInvalidLength(length: Object) {
      ThrowRangeError(kInvalidTypedArrayLength, length);
    }
  }

  // 22.2.4 The TypedArray Constructors
  // ES #sec-typedarray-constructors
  transitioning builtin CreateTypedArray(
      context: Context, target: JSFunction, newTarget: JSReceiver, arg1: JSAny,
      arg2: JSAny, arg3: JSAny): JSTypedArray {
    assert(IsConstructor(target));
    // 4. Let O be ? AllocateTypedArray(constructorName, NewTarget,
    // "%TypedArrayPrototype%").
    const map = GetDerivedMap(target, newTarget);

    // 5. Let elementSize be the Number value of the Element Size value in Table
    // 56 for constructorName.
    const elementsInfo: typed_array::TypedArrayElementsInfo =
        typed_array::GetTypedArrayElementsInfo(map);

    try {
      typeswitch (arg1) {
        case (length: Smi): {
          goto IfConstructByLength(length);
        }
        case (buffer: JSArrayBuffer): {
          return ConstructByArrayBuffer(map, buffer, arg2, arg3, elementsInfo);
        }
        case (typedArray: JSTypedArray): {
          ConstructByTypedArray(typedArray) otherwise IfConstructByArrayLike;
        }
        case (obj: JSReceiver): {
          ConstructByJSReceiver(obj) otherwise IfConstructByArrayLike;
        }
        // The first argument was a number or fell through and is treated as
        // a number. https://tc39.github.io/ecma262/#sec-typedarray-length
        case (lengthObj: JSAny): {
          goto IfConstructByLength(lengthObj);
        }
      }
    }
    label IfConstructByLength(length: JSAny) {
      return ConstructByLength(map, length, elementsInfo);
    }
    label IfConstructByArrayLike(
        arrayLike: JSReceiver, length: Number, bufferConstructor: JSReceiver) {
      return ConstructByArrayLike(
          map, arrayLike, length, elementsInfo, bufferConstructor);
    }
  }

  transitioning macro TypedArraySpeciesCreate(implicit context: Context)(
      methodName: constexpr string, numArgs: constexpr int31,
      exemplar: JSTypedArray, arg0: JSAny, arg1: JSAny,
      arg2: JSAny): JSTypedArray {
    const defaultConstructor = GetDefaultConstructor(exemplar);

    try {
      if (!IsPrototypeTypedArrayPrototype(exemplar.map)) goto IfSlow;
      if (IsTypedArraySpeciesProtectorCellInvalid()) goto IfSlow;

      const typedArray = CreateTypedArray(
          context, defaultConstructor, defaultConstructor, arg0, arg1, arg2);

      // It is assumed that the CreateTypedArray builtin does not produce a
      // typed array that fails ValidateTypedArray
      assert(!IsDetachedBuffer(typedArray.buffer));

      return typedArray;
    }
    label IfSlow deferred {
      const constructor =
          Cast<Constructor>(SpeciesConstructor(exemplar, defaultConstructor))
          otherwise unreachable;

      // TODO(pwong): Simplify and remove numArgs when varargs are supported in
      // macros.
      let newObj: JSAny = Undefined;
      if constexpr (numArgs == 1) {
        newObj = Construct(constructor, arg0);
      } else {
        assert(numArgs == 3);
        newObj = Construct(constructor, arg0, arg1, arg2);
      }

      return typed_array::ValidateTypedArray(context, newObj, methodName);
    }
  }

  @export
  transitioning macro TypedArraySpeciesCreateByLength(implicit context:
                                                          Context)(
      methodName: constexpr string, exemplar: JSTypedArray,
      length: PositiveSmi): JSTypedArray {
    const numArgs: constexpr int31 = 1;
    const typedArray: JSTypedArray = TypedArraySpeciesCreate(
        methodName, numArgs, exemplar, length, Undefined, Undefined);
    if (typedArray.length < Convert<uintptr>(length)) deferred {
        ThrowTypeError(kTypedArrayTooShort);
      }

    return typedArray;
  }
}