Squashed 'third_party/flatbuffers/' changes from d6a8dbd26..338393f85

338393f85 Documentation updates for Optional Scalars (#6014) (#6270)
c27bc2d76 [C++] Add ParseJson(), Parser(Parser&&), update fuzzers (#6284)
bc518a512 Fixed FlexBufferBuilder asserting on duplicate keys
100c59054 Added a few more paths for auto labeler (#6281)
e58c18244 Add --require-explicit-ids to require explicit ids (#6277)
69a8b2a57 idl_gen_json_schema.cpp: Changed generation of array element types (#6253)
25eba6f35 fix typo (#6280)
e1f0f75ba Updated Ms build Action to fix build issue (#6279)
faeb04fbe Add type annotation to unspecified array (#6264)
537212afe [Swift] Adds a format file and reformats the swift project (#6250)
6764f25d9 Adds a fix for enum generation (#6263)

Change-Id: I716bd4d2521fb0a673e50a699cef761e042052b2
git-subtree-dir: third_party/flatbuffers
git-subtree-split: 338393f854eb5ba24761a22cd9316ff5cee4eab0
diff --git a/swift/Sources/FlatBuffers/ByteBuffer.swift b/swift/Sources/FlatBuffers/ByteBuffer.swift
index 46ae1c5..7df41a7 100644
--- a/swift/Sources/FlatBuffers/ByteBuffer.swift
+++ b/swift/Sources/FlatBuffers/ByteBuffer.swift
@@ -1,345 +1,398 @@
+/*
+ * Copyright 2020 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.
+ */
+
 import Foundation
 
 public struct ByteBuffer {
-    
-    /// Storage is a container that would hold the memory pointer to solve the issue of
-    /// deallocating the memory that was held by (memory: UnsafeMutableRawPointer)
-    @usableFromInline final class Storage {
-        // This storage doesn't own the memory, therefore, we won't deallocate on deinit.
-        private let unowned: Bool
-        /// pointer to the start of the buffer object in memory
-        var memory: UnsafeMutableRawPointer
-        /// Capacity of UInt8 the buffer can hold
-        var capacity: Int
-        
-        init(count: Int, alignment: Int) {
-            memory = UnsafeMutableRawPointer.allocate(byteCount: count, alignment: alignment)
-            capacity = count
-            unowned = false
-        }
 
-        init(memory: UnsafeMutableRawPointer, capacity: Int, unowned: Bool) {
-            self.memory = memory
-            self.capacity = capacity
-            self.unowned = unowned
-        }
-        
-        deinit {
-            if !unowned {
-              memory.deallocate()
-            }
-        }
-        
-        func copy(from ptr: UnsafeRawPointer, count: Int) {
-            assert(!unowned, "copy should NOT be called on a buffer that is built by assumingMemoryBound")
-            memory.copyMemory(from: ptr, byteCount: count)
-        }
-        
-        func initialize(for size: Int) {
-            assert(!unowned, "initalize should NOT be called on a buffer that is built by assumingMemoryBound")
-            memset(memory, 0, size)
-        }
-        
-        /// Reallocates the buffer incase the object to be written doesnt fit in the current buffer
-        /// - Parameter size: Size of the current object
-        @usableFromInline internal func reallocate(_ size: Int, writerSize: Int, alignment: Int) {
-            let currentWritingIndex = capacity &- writerSize
-            while capacity <= writerSize &+ size {
-                capacity = capacity << 1
-            }
-            
-            /// solution take from Apple-NIO
-            capacity = capacity.convertToPowerofTwo
-            
-            let newData = UnsafeMutableRawPointer.allocate(byteCount: capacity, alignment: alignment)
-            memset(newData, 0, capacity &- writerSize)
-            memcpy(newData.advanced(by: capacity &- writerSize), memory.advanced(by: currentWritingIndex), writerSize)
-            memory.deallocate()
-            memory = newData
-        }
-    }
-    
-    @usableFromInline var _storage: Storage
-    
-    /// The size of the elements written to the buffer + their paddings
-    private var _writerSize: Int = 0
-    /// Aliginment of the current  memory being written to the buffer
-    internal var alignment = 1
-    /// Current Index which is being used to write to the buffer, it is written from the end to the start of the buffer
-    internal var writerIndex: Int { return _storage.capacity &- _writerSize }
+  /// Storage is a container that would hold the memory pointer to solve the issue of
+  /// deallocating the memory that was held by (memory: UnsafeMutableRawPointer)
+  @usableFromInline
+  final class Storage {
+    // This storage doesn't own the memory, therefore, we won't deallocate on deinit.
+    private let unowned: Bool
+    /// pointer to the start of the buffer object in memory
+    var memory: UnsafeMutableRawPointer
+    /// Capacity of UInt8 the buffer can hold
+    var capacity: Int
 
-    /// Reader is the position of the current Writer Index (capacity - size)
-    public var reader: Int { return writerIndex }
-    /// Current size of the buffer
-    public var size: UOffset { return UOffset(_writerSize) }
-    /// Public Pointer to the buffer object in memory. This should NOT be modified for any reason
-    public var memory: UnsafeMutableRawPointer { return _storage.memory }
-    /// Current capacity for the buffer
-    public var capacity: Int { return _storage.capacity }
-
-    /// Constructor that creates a Flatbuffer object from a UInt8
-    /// - Parameter bytes: Array of UInt8
-    public init(bytes: [UInt8]) {
-        var b = bytes
-        _storage = Storage(count: bytes.count, alignment: alignment)
-        _writerSize = _storage.capacity
-        b.withUnsafeMutableBytes { bufferPointer in
-            self._storage.copy(from: bufferPointer.baseAddress!, count: bytes.count)
-        }
+    init(count: Int, alignment: Int) {
+      memory = UnsafeMutableRawPointer.allocate(byteCount: count, alignment: alignment)
+      capacity = count
+      unowned = false
     }
 
-    /// Constructor that creates a Flatbuffer from the Swift Data type object
-    /// - Parameter data: Swift data Object
-    public init(data: Data) {
-        var b = data
-        _storage = Storage(count: data.count, alignment: alignment)
-        _writerSize = _storage.capacity
-        b.withUnsafeMutableBytes { bufferPointer in
-            self._storage.copy(from: bufferPointer.baseAddress!, count: data.count)
-        }
+    init(memory: UnsafeMutableRawPointer, capacity: Int, unowned: Bool) {
+      self.memory = memory
+      self.capacity = capacity
+      self.unowned = unowned
     }
 
-    /// Constructor that creates a Flatbuffer instance with a size
-    /// - Parameter size: Length of the buffer
-    init(initialSize size: Int) {
-        let size = size.convertToPowerofTwo
-        _storage = Storage(count: size, alignment: alignment)
-        _storage.initialize(for: size)
-    }
-  
-    #if swift(>=5.0)
-    /// Constructor that creates a Flatbuffer object from a ContiguousBytes
-    /// - Parameters:
-    ///   - contiguousBytes: Binary stripe to use as the buffer
-    ///   - count: amount of readable bytes
-    public init<Bytes: ContiguousBytes>(
-        contiguousBytes: Bytes,
-        count: Int
-    ) {
-        _storage = Storage(count: count, alignment: alignment)
-        _writerSize = _storage.capacity
-        contiguousBytes.withUnsafeBytes { buf in
-            _storage.copy(from: buf.baseAddress!, count: buf.count)
-        }
-    }
-    #endif
-    
-    /// Constructor that creates a Flatbuffer from unsafe memory region without copying
-    /// - Parameter assumingMemoryBound: The unsafe memory region
-    /// - Parameter capacity: The size of the given memory region
-    public init(assumingMemoryBound memory: UnsafeMutableRawPointer, capacity: Int) {
-        _storage = Storage(memory: memory, capacity: capacity, unowned: true)
-        _writerSize = capacity
+    deinit {
+      if !unowned {
+        memory.deallocate()
+      }
     }
 
-    /// Creates a copy of the buffer that's being built by calling sizedBuffer
-    /// - Parameters:
-    ///   - memory: Current memory of the buffer
-    ///   - count: count of bytes
-    internal init(memory: UnsafeMutableRawPointer, count: Int) {
-        _storage = Storage(count: count, alignment: alignment)
-        _storage.copy(from: memory, count: count)
-        _writerSize = _storage.capacity
+    func copy(from ptr: UnsafeRawPointer, count: Int) {
+      assert(
+        !unowned,
+        "copy should NOT be called on a buffer that is built by assumingMemoryBound")
+      memory.copyMemory(from: ptr, byteCount: count)
     }
 
-    /// Creates a copy of the existing flatbuffer, by copying it to a different memory.
-    /// - Parameters:
-    ///   - memory: Current memory of the buffer
-    ///   - count: count of bytes
-    ///   - removeBytes: Removes a number of bytes from the current size
-    internal init(memory: UnsafeMutableRawPointer, count: Int, removing removeBytes: Int) {
-        _storage = Storage(count: count, alignment: alignment)
-        _storage.copy(from: memory, count: count)
-        _writerSize = removeBytes
+    func initialize(for size: Int) {
+      assert(
+        !unowned,
+        "initalize should NOT be called on a buffer that is built by assumingMemoryBound")
+      memset(memory, 0, size)
     }
 
-    /// Fills the buffer with padding by adding to the writersize
-    /// - Parameter padding: Amount of padding between two to be serialized objects
-    @usableFromInline mutating func fill(padding: Int) {
-        assert(padding >= 0, "Fill should be larger than or equal to zero")
-        ensureSpace(size: padding)
-        _writerSize = _writerSize &+ (MemoryLayout<UInt8>.size &* padding)
-    }
-    
-    ///Adds an array of type Scalar to the buffer memory
-    /// - Parameter elements: An array of Scalars
-    @usableFromInline mutating func push<T: Scalar>(elements: [T]) {
-        let size = elements.count &* MemoryLayout<T>.size
-        ensureSpace(size: size)
-        elements.reversed().forEach { (s) in
-            push(value: s, len: MemoryLayout.size(ofValue: s))
-        }
-    }
+    /// Reallocates the buffer incase the object to be written doesnt fit in the current buffer
+    /// - Parameter size: Size of the current object
+    @usableFromInline
+    internal func reallocate(_ size: Int, writerSize: Int, alignment: Int) {
+      let currentWritingIndex = capacity &- writerSize
+      while capacity <= writerSize &+ size {
+        capacity = capacity << 1
+      }
 
-    /// A custom type of structs that are padded according to the flatbuffer padding,
-    /// - Parameters:
-    ///   - value: Pointer to the object in memory
-    ///   - size: Size of Value being written to the buffer
-    @available(*, deprecated, message: "0.9.0 will be removing the following method. Regenerate the code")
-    @usableFromInline mutating func push(struct value: UnsafeMutableRawPointer, size: Int) {
-        ensureSpace(size: size)
-        memcpy(_storage.memory.advanced(by: writerIndex &- size), value, size)
-        defer { value.deallocate() }
-        _writerSize = _writerSize &+ size
-    }
-    
-    /// Prepares the buffer to receive a struct of certian size.
-    /// The alignment of the memory is already handled since we already called preAlign
-    /// - Parameter size: size of the struct
-    @usableFromInline mutating func prepareBufferToReceiveStruct(of size: Int) {
-        ensureSpace(size: size)
-        _writerSize = _writerSize &+ size
-    }
-    
-    /// Reverse the input direction to the buffer, since `FlatBuffers` uses a back to front, following method will take current `writerIndex`
-    /// and writes front to back into the buffer, respecting the padding & the alignment
-    /// - Parameters:
-    ///   - value: value of type Scalar
-    ///   - position: position relative to the `writerIndex`
-    ///   - len: length of the value in terms of bytes
-    @usableFromInline mutating func reversePush<T: Scalar>(value: T, position: Int, len: Int) {
-        var v = value
-        memcpy(_storage.memory.advanced(by: writerIndex &+ position), &v, len)
-    }
+      /// solution take from Apple-NIO
+      capacity = capacity.convertToPowerofTwo
 
-    /// Adds an object of type Scalar into the buffer
-    /// - Parameters:
-    ///   - value: Object  that will be written to the buffer
-    ///   - len: Offset to subtract from the WriterIndex
-    @usableFromInline mutating func push<T: Scalar>(value: T, len: Int) {
-        ensureSpace(size: len)
-        var v = value
-        memcpy(_storage.memory.advanced(by: writerIndex &- len), &v, len)
-        _writerSize = _writerSize &+ len
+      let newData = UnsafeMutableRawPointer.allocate(byteCount: capacity, alignment: alignment)
+      memset(newData, 0, capacity &- writerSize)
+      memcpy(
+        newData.advanced(by: capacity &- writerSize),
+        memory.advanced(by: currentWritingIndex),
+        writerSize)
+      memory.deallocate()
+      memory = newData
     }
+  }
 
-    /// Adds a string to the buffer using swift.utf8 object
-    /// - Parameter str: String that will be added to the buffer
-    /// - Parameter len: length of the string
-    @usableFromInline mutating func push(string str: String, len: Int) {
-        ensureSpace(size: len)
-        if str.utf8.withContiguousStorageIfAvailable({ self.push(bytes: $0, len: len) }) != nil {
-        } else {
-            let utf8View = str.utf8
-            for c in utf8View.reversed() {
-                push(value: c, len: 1)
-            }
-        }
-    }
+  @usableFromInline var _storage: Storage
 
-    /// Writes a string to Bytebuffer using UTF8View
-    /// - Parameters:
-    ///   - bytes: Pointer to the view
-    ///   - len: Size of string
-    @usableFromInline mutating internal func push(bytes: UnsafeBufferPointer<String.UTF8View.Element>, len: Int) -> Bool {
-        memcpy(_storage.memory.advanced(by: writerIndex &- len), UnsafeRawPointer(bytes.baseAddress!), len)
-        _writerSize = _writerSize &+ len
-        return true
-    }
+  /// The size of the elements written to the buffer + their paddings
+  private var _writerSize: Int = 0
+  /// Aliginment of the current  memory being written to the buffer
+  internal var alignment = 1
+  /// Current Index which is being used to write to the buffer, it is written from the end to the start of the buffer
+  internal var writerIndex: Int { _storage.capacity &- _writerSize }
 
-    /// Write stores an object into the buffer directly or indirectly.
-    ///
-    /// Direct: ignores the capacity of buffer which would mean we are referring to the direct point in memory
-    /// indirect: takes into respect the current capacity of the buffer (capacity - index), writing to the buffer from the end
-    /// - Parameters:
-    ///   - value: Value that needs to be written to the buffer
-    ///   - index: index to write to
-    ///   - direct: Should take into consideration the capacity of the buffer
-    func write<T>(value: T, index: Int, direct: Bool = false) {
-        var index = index
-        if !direct {
-            index = _storage.capacity &- index
-        }
-        assert(index < _storage.capacity, "Write index is out of writing bound")
-        assert(index >= 0, "Writer index should be above zero")
-        _storage.memory.storeBytes(of: value, toByteOffset: index, as: T.self)
-    }
+  /// Reader is the position of the current Writer Index (capacity - size)
+  public var reader: Int { writerIndex }
+  /// Current size of the buffer
+  public var size: UOffset { UOffset(_writerSize) }
+  /// Public Pointer to the buffer object in memory. This should NOT be modified for any reason
+  public var memory: UnsafeMutableRawPointer { _storage.memory }
+  /// Current capacity for the buffer
+  public var capacity: Int { _storage.capacity }
 
-    /// Makes sure that buffer has enouch space for each of the objects that will be written into it
-    /// - Parameter size: size of object
-    @discardableResult
-    @usableFromInline mutating func ensureSpace(size: Int) -> Int {
-        if size &+ _writerSize > _storage.capacity {
-            _storage.reallocate(size, writerSize: _writerSize, alignment: alignment)
-        }
-        assert(size < FlatBufferMaxSize, "Buffer can't grow beyond 2 Gigabytes")
-        return size
+  /// Constructor that creates a Flatbuffer object from a UInt8
+  /// - Parameter bytes: Array of UInt8
+  public init(bytes: [UInt8]) {
+    var b = bytes
+    _storage = Storage(count: bytes.count, alignment: alignment)
+    _writerSize = _storage.capacity
+    b.withUnsafeMutableBytes { bufferPointer in
+      self._storage.copy(from: bufferPointer.baseAddress!, count: bytes.count)
     }
-    
-    /// pops the written VTable if it's already written into the buffer
-    /// - Parameter size: size of the `VTable`
-    @usableFromInline mutating internal func pop(_ size: Int) {
-        assert((_writerSize &- size) > 0, "New size should NOT be a negative number")
-        memset(_storage.memory.advanced(by: writerIndex), 0, _writerSize &- size)
-        _writerSize = size
-    }
-    
-    /// Clears the current size of the buffer
-    mutating public func clearSize() {
-        _writerSize = 0
-    }
+  }
 
-    /// Clears the current instance of the buffer, replacing it with new memory
-    mutating public func clear() {
-        _writerSize = 0
-        alignment = 1
-        _storage.initialize(for: _storage.capacity)
+  /// Constructor that creates a Flatbuffer from the Swift Data type object
+  /// - Parameter data: Swift data Object
+  public init(data: Data) {
+    var b = data
+    _storage = Storage(count: data.count, alignment: alignment)
+    _writerSize = _storage.capacity
+    b.withUnsafeMutableBytes { bufferPointer in
+      self._storage.copy(from: bufferPointer.baseAddress!, count: data.count)
     }
-    
-    /// Reads an object from the buffer
-    /// - Parameters:
-    ///   - def: Type of the object
-    ///   - position: the index of the object in the buffer
-    public func read<T>(def: T.Type, position: Int) -> T {
-        assert(position + MemoryLayout<T>.size <= _storage.capacity, "Reading out of bounds is illegal")
-        return _storage.memory.advanced(by: position).load(as: T.self)
-    }
+  }
 
-    /// Reads a slice from the memory assuming a type of T
-    /// - Parameters:
-    ///   - index: index of the object to be read from the buffer
-    ///   - count: count of bytes in memory
-    public func readSlice<T>(index: Int32,
-                             count: Int32) -> [T] {
-        let _index = Int(index)
-        let _count = Int(count)
-        assert(_index + _count <= _storage.capacity, "Reading out of bounds is illegal")
-        let start = _storage.memory.advanced(by: _index).assumingMemoryBound(to: T.self)
-        let array = UnsafeBufferPointer(start: start, count: _count)
-        return Array(array)
-    }
+  /// Constructor that creates a Flatbuffer instance with a size
+  /// - Parameter size: Length of the buffer
+  init(initialSize size: Int) {
+    let size = size.convertToPowerofTwo
+    _storage = Storage(count: size, alignment: alignment)
+    _storage.initialize(for: size)
+  }
 
-    /// Reads a string from the buffer and encodes it to a swift string
-    /// - Parameters:
-    ///   - index: index of the string in the buffer
-    ///   - count: length of the string
-    ///   - type: Encoding of the string
-    public func readString(at index: Int32,
-                           count: Int32,
-                           type: String.Encoding = .utf8) -> String? {
-        let _index = Int(index)
-        let _count = Int(count)
-        assert(_index + _count <= _storage.capacity, "Reading out of bounds is illegal")
-        let start = _storage.memory.advanced(by: _index).assumingMemoryBound(to: UInt8.self)
-        let bufprt = UnsafeBufferPointer(start: start, count: _count)
-        return String(bytes: Array(bufprt), encoding: type)
+  #if swift(>=5.0)
+  /// Constructor that creates a Flatbuffer object from a ContiguousBytes
+  /// - Parameters:
+  ///   - contiguousBytes: Binary stripe to use as the buffer
+  ///   - count: amount of readable bytes
+  public init<Bytes: ContiguousBytes>(
+    contiguousBytes: Bytes,
+    count: Int)
+  {
+    _storage = Storage(count: count, alignment: alignment)
+    _writerSize = _storage.capacity
+    contiguousBytes.withUnsafeBytes { buf in
+      _storage.copy(from: buf.baseAddress!, count: buf.count)
     }
+  }
+  #endif
 
-    /// Creates a new Flatbuffer object that's duplicated from the current one
-    /// - Parameter removeBytes: the amount of bytes to remove from the current Size
-    public func duplicate(removing removeBytes: Int = 0) -> ByteBuffer {
-        assert(removeBytes > 0, "Can NOT remove negative bytes")
-        assert(removeBytes < _storage.capacity, "Can NOT remove more bytes than the ones allocated")
-        return ByteBuffer(memory: _storage.memory, count: _storage.capacity, removing: _writerSize &- removeBytes)
+  /// Constructor that creates a Flatbuffer from unsafe memory region without copying
+  /// - Parameter assumingMemoryBound: The unsafe memory region
+  /// - Parameter capacity: The size of the given memory region
+  public init(assumingMemoryBound memory: UnsafeMutableRawPointer, capacity: Int) {
+    _storage = Storage(memory: memory, capacity: capacity, unowned: true)
+    _writerSize = capacity
+  }
+
+  /// Creates a copy of the buffer that's being built by calling sizedBuffer
+  /// - Parameters:
+  ///   - memory: Current memory of the buffer
+  ///   - count: count of bytes
+  internal init(memory: UnsafeMutableRawPointer, count: Int) {
+    _storage = Storage(count: count, alignment: alignment)
+    _storage.copy(from: memory, count: count)
+    _writerSize = _storage.capacity
+  }
+
+  /// Creates a copy of the existing flatbuffer, by copying it to a different memory.
+  /// - Parameters:
+  ///   - memory: Current memory of the buffer
+  ///   - count: count of bytes
+  ///   - removeBytes: Removes a number of bytes from the current size
+  internal init(memory: UnsafeMutableRawPointer, count: Int, removing removeBytes: Int) {
+    _storage = Storage(count: count, alignment: alignment)
+    _storage.copy(from: memory, count: count)
+    _writerSize = removeBytes
+  }
+
+  /// Fills the buffer with padding by adding to the writersize
+  /// - Parameter padding: Amount of padding between two to be serialized objects
+  @usableFromInline
+  mutating func fill(padding: Int) {
+    assert(padding >= 0, "Fill should be larger than or equal to zero")
+    ensureSpace(size: padding)
+    _writerSize = _writerSize &+ (MemoryLayout<UInt8>.size &* padding)
+  }
+
+  ///Adds an array of type Scalar to the buffer memory
+  /// - Parameter elements: An array of Scalars
+  @usableFromInline
+  mutating func push<T: Scalar>(elements: [T]) {
+    let size = elements.count &* MemoryLayout<T>.size
+    ensureSpace(size: size)
+    elements.reversed().forEach { s in
+      push(value: s, len: MemoryLayout.size(ofValue: s))
     }
+  }
+
+  /// A custom type of structs that are padded according to the flatbuffer padding,
+  /// - Parameters:
+  ///   - value: Pointer to the object in memory
+  ///   - size: Size of Value being written to the buffer
+  @available(
+    *,
+    deprecated,
+    message: "0.9.0 will be removing the following method. Regenerate the code")
+  @usableFromInline
+  mutating func push(struct value: UnsafeMutableRawPointer, size: Int) {
+    ensureSpace(size: size)
+    memcpy(_storage.memory.advanced(by: writerIndex &- size), value, size)
+    defer { value.deallocate() }
+    _writerSize = _writerSize &+ size
+  }
+
+  /// Prepares the buffer to receive a struct of certian size.
+  /// The alignment of the memory is already handled since we already called preAlign
+  /// - Parameter size: size of the struct
+  @usableFromInline
+  mutating func prepareBufferToReceiveStruct(of size: Int) {
+    ensureSpace(size: size)
+    _writerSize = _writerSize &+ size
+  }
+
+  /// Reverse the input direction to the buffer, since `FlatBuffers` uses a back to front, following method will take current `writerIndex`
+  /// and writes front to back into the buffer, respecting the padding & the alignment
+  /// - Parameters:
+  ///   - value: value of type Scalar
+  ///   - position: position relative to the `writerIndex`
+  ///   - len: length of the value in terms of bytes
+  @usableFromInline
+  mutating func reversePush<T: Scalar>(value: T, position: Int, len: Int) {
+    var v = value
+    memcpy(_storage.memory.advanced(by: writerIndex &+ position), &v, len)
+  }
+
+  /// Adds an object of type Scalar into the buffer
+  /// - Parameters:
+  ///   - value: Object  that will be written to the buffer
+  ///   - len: Offset to subtract from the WriterIndex
+  @usableFromInline
+  mutating func push<T: Scalar>(value: T, len: Int) {
+    ensureSpace(size: len)
+    var v = value
+    memcpy(_storage.memory.advanced(by: writerIndex &- len), &v, len)
+    _writerSize = _writerSize &+ len
+  }
+
+  /// Adds a string to the buffer using swift.utf8 object
+  /// - Parameter str: String that will be added to the buffer
+  /// - Parameter len: length of the string
+  @usableFromInline
+  mutating func push(string str: String, len: Int) {
+    ensureSpace(size: len)
+    if str.utf8.withContiguousStorageIfAvailable({ self.push(bytes: $0, len: len) }) != nil {
+    } else {
+      let utf8View = str.utf8
+      for c in utf8View.reversed() {
+        push(value: c, len: 1)
+      }
+    }
+  }
+
+  /// Writes a string to Bytebuffer using UTF8View
+  /// - Parameters:
+  ///   - bytes: Pointer to the view
+  ///   - len: Size of string
+  @usableFromInline
+  mutating internal func push(
+    bytes: UnsafeBufferPointer<String.UTF8View.Element>,
+    len: Int) -> Bool
+  {
+    memcpy(
+      _storage.memory.advanced(by: writerIndex &- len),
+      UnsafeRawPointer(bytes.baseAddress!),
+      len)
+    _writerSize = _writerSize &+ len
+    return true
+  }
+
+  /// Write stores an object into the buffer directly or indirectly.
+  ///
+  /// Direct: ignores the capacity of buffer which would mean we are referring to the direct point in memory
+  /// indirect: takes into respect the current capacity of the buffer (capacity - index), writing to the buffer from the end
+  /// - Parameters:
+  ///   - value: Value that needs to be written to the buffer
+  ///   - index: index to write to
+  ///   - direct: Should take into consideration the capacity of the buffer
+  func write<T>(value: T, index: Int, direct: Bool = false) {
+    var index = index
+    if !direct {
+      index = _storage.capacity &- index
+    }
+    assert(index < _storage.capacity, "Write index is out of writing bound")
+    assert(index >= 0, "Writer index should be above zero")
+    _storage.memory.storeBytes(of: value, toByteOffset: index, as: T.self)
+  }
+
+  /// Makes sure that buffer has enouch space for each of the objects that will be written into it
+  /// - Parameter size: size of object
+  @discardableResult
+  @usableFromInline
+  mutating func ensureSpace(size: Int) -> Int {
+    if size &+ _writerSize > _storage.capacity {
+      _storage.reallocate(size, writerSize: _writerSize, alignment: alignment)
+    }
+    assert(size < FlatBufferMaxSize, "Buffer can't grow beyond 2 Gigabytes")
+    return size
+  }
+
+  /// pops the written VTable if it's already written into the buffer
+  /// - Parameter size: size of the `VTable`
+  @usableFromInline
+  mutating internal func pop(_ size: Int) {
+    assert((_writerSize &- size) > 0, "New size should NOT be a negative number")
+    memset(_storage.memory.advanced(by: writerIndex), 0, _writerSize &- size)
+    _writerSize = size
+  }
+
+  /// Clears the current size of the buffer
+  mutating public func clearSize() {
+    _writerSize = 0
+  }
+
+  /// Clears the current instance of the buffer, replacing it with new memory
+  mutating public func clear() {
+    _writerSize = 0
+    alignment = 1
+    _storage.initialize(for: _storage.capacity)
+  }
+
+  /// Reads an object from the buffer
+  /// - Parameters:
+  ///   - def: Type of the object
+  ///   - position: the index of the object in the buffer
+  public func read<T>(def: T.Type, position: Int) -> T {
+    assert(
+      position + MemoryLayout<T>.size <= _storage.capacity,
+      "Reading out of bounds is illegal")
+    return _storage.memory.advanced(by: position).load(as: T.self)
+  }
+
+  /// Reads a slice from the memory assuming a type of T
+  /// - Parameters:
+  ///   - index: index of the object to be read from the buffer
+  ///   - count: count of bytes in memory
+  public func readSlice<T>(
+    index: Int32,
+    count: Int32) -> [T]
+  {
+    let _index = Int(index)
+    let _count = Int(count)
+    assert(_index + _count <= _storage.capacity, "Reading out of bounds is illegal")
+    let start = _storage.memory.advanced(by: _index).assumingMemoryBound(to: T.self)
+    let array = UnsafeBufferPointer(start: start, count: _count)
+    return Array(array)
+  }
+
+  /// Reads a string from the buffer and encodes it to a swift string
+  /// - Parameters:
+  ///   - index: index of the string in the buffer
+  ///   - count: length of the string
+  ///   - type: Encoding of the string
+  public func readString(
+    at index: Int32,
+    count: Int32,
+    type: String.Encoding = .utf8) -> String?
+  {
+    let _index = Int(index)
+    let _count = Int(count)
+    assert(_index + _count <= _storage.capacity, "Reading out of bounds is illegal")
+    let start = _storage.memory.advanced(by: _index).assumingMemoryBound(to: UInt8.self)
+    let bufprt = UnsafeBufferPointer(start: start, count: _count)
+    return String(bytes: Array(bufprt), encoding: type)
+  }
+
+  /// Creates a new Flatbuffer object that's duplicated from the current one
+  /// - Parameter removeBytes: the amount of bytes to remove from the current Size
+  public func duplicate(removing removeBytes: Int = 0) -> ByteBuffer {
+    assert(removeBytes > 0, "Can NOT remove negative bytes")
+    assert(removeBytes < _storage.capacity, "Can NOT remove more bytes than the ones allocated")
+    return ByteBuffer(
+      memory: _storage.memory,
+      count: _storage.capacity,
+      removing: _writerSize &- removeBytes)
+  }
 }
 
 extension ByteBuffer: CustomDebugStringConvertible {
 
-    public var debugDescription: String {
-        """
-        buffer located at: \(_storage.memory), with capacity of \(_storage.capacity)
-        { writerSize: \(_writerSize), readerSize: \(reader), writerIndex: \(writerIndex) }
-        """
-    }
+  public var debugDescription: String {
+    """
+    buffer located at: \(_storage.memory), with capacity of \(_storage.capacity)
+    { writerSize: \(_writerSize), readerSize: \(reader), writerIndex: \(writerIndex) }
+    """
+  }
 }