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/*
* Copyright 2021 Google Inc. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#if !os(WASI)
import Foundation
#else
import SwiftOverlayShims
#endif
/// Mutable is a protocol that allows us to mutate Scalar values within a ``ByteBuffer``
public protocol Mutable {
/// makes Flatbuffer accessed within the Protocol
var bb: ByteBuffer { get }
/// makes position of the ``Table``/``struct`` accessed within the Protocol
var postion: Int32 { get }
}
extension Mutable {
/// Mutates the memory in the buffer, this is only called from the access function of ``Table`` and ``struct``
/// - Parameters:
/// - value: New value to be inserted to the buffer
/// - index: index of the Element
func mutate<T: Scalar>(value: T, o: Int32) -> Bool {
guard o != 0 else { return false }
bb.write(value: value, index: Int(o), direct: true)
return true
}
}
extension Mutable where Self == Table {
/// Mutates a value by calling mutate with respect to the position in a ``Table``
/// - Parameters:
/// - value: New value to be inserted to the buffer
/// - index: index of the Element
public func mutate<T: Scalar>(_ value: T, index: Int32) -> Bool {
guard index != 0 else { return false }
return mutate(value: value, o: index + postion)
}
/// Directly mutates the element by calling mutate
///
/// Mutates the Element at index ignoring the current position by calling mutate
/// - Parameters:
/// - value: New value to be inserted to the buffer
/// - index: index of the Element
public func directMutate<T: Scalar>(_ value: T, index: Int32) -> Bool {
mutate(value: value, o: index)
}
}
extension Mutable where Self == Struct {
/// Mutates a value by calling mutate with respect to the position in the struct
/// - Parameters:
/// - value: New value to be inserted to the buffer
/// - index: index of the Element
public func mutate<T: Scalar>(_ value: T, index: Int32) -> Bool {
mutate(value: value, o: index + postion)
}
/// Directly mutates the element by calling mutate
///
/// Mutates the Element at index ignoring the current position by calling mutate
/// - Parameters:
/// - value: New value to be inserted to the buffer
/// - index: index of the Element
public func directMutate<T: Scalar>(_ value: T, index: Int32) -> Bool {
mutate(value: value, o: index)
}
}
extension Struct: Mutable {}
extension Table: Mutable {}