xref: /aosp_15_r20/external/flatbuffers/swift/Sources/FlatBuffers/Constants.swift (revision 890232f25432b36107d06881e0a25aaa6b473652)
1 /*
2  * Copyright 2021 Google Inc. All rights reserved.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *     http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #if !os(WASI)
18   #if os(Linux)
19   import CoreFoundation
20   #else
21   import Foundation
22   #endif
23 #else
24 import SwiftOverlayShims
25 #endif
26 
27 /// A boolean to see if the system is littleEndian
28 let isLitteEndian: Bool = {
29   let number: UInt32 = 0x12345678
30   return number == number.littleEndian
31 }()
32 /// Constant for the file id length
33 let FileIdLength = 4
34 /// Type aliases
35 public typealias Byte = UInt8
36 public typealias UOffset = UInt32
37 public typealias SOffset = Int32
38 public typealias VOffset = UInt16
39 /// Maximum size for a buffer
40 public let FlatBufferMaxSize = UInt32
41   .max << ((MemoryLayout<SOffset>.size * 8 - 1) - 1)
42 
43 /// Protocol that All Scalars should conform to
44 ///
45 /// Scalar is used to conform all the numbers that can be represented in a FlatBuffer. It's used to write/read from the buffer.
46 public protocol Scalar: Equatable {
47   associatedtype NumericValue
48   var convertedEndian: NumericValue { get }
49 }
50 
51 extension Scalar where Self: Verifiable {}
52 
53 extension Scalar where Self: FixedWidthInteger {
54   /// Converts the value from BigEndian to LittleEndian
55   ///
56   /// Converts values to little endian on machines that work with BigEndian, however this is NOT TESTED yet.
57   public var convertedEndian: NumericValue {
58     self as! Self.NumericValue
59   }
60 }
61 
62 extension Double: Scalar, Verifiable {
63   public typealias NumericValue = UInt64
64 
65   public var convertedEndian: UInt64 {
66     bitPattern.littleEndian
67   }
68 }
69 
70 extension Float32: Scalar, Verifiable {
71   public typealias NumericValue = UInt32
72 
73   public var convertedEndian: UInt32 {
74     bitPattern.littleEndian
75   }
76 }
77 
78 extension Bool: Scalar, Verifiable {
79   public var convertedEndian: UInt8 {
80     self == true ? 1 : 0
81   }
82 
83   public typealias NumericValue = UInt8
84 }
85 
86 extension Int: Scalar, Verifiable {
87   public typealias NumericValue = Int
88 }
89 
90 extension Int8: Scalar, Verifiable {
91   public typealias NumericValue = Int8
92 }
93 
94 extension Int16: Scalar, Verifiable {
95   public typealias NumericValue = Int16
96 }
97 
98 extension Int32: Scalar, Verifiable {
99   public typealias NumericValue = Int32
100 }
101 
102 extension Int64: Scalar, Verifiable {
103   public typealias NumericValue = Int64
104 }
105 
106 extension UInt8: Scalar, Verifiable {
107   public typealias NumericValue = UInt8
108 }
109 
110 extension UInt16: Scalar, Verifiable {
111   public typealias NumericValue = UInt16
112 }
113 
114 extension UInt32: Scalar, Verifiable {
115   public typealias NumericValue = UInt32
116 }
117 
118 extension UInt64: Scalar, Verifiable {
119   public typealias NumericValue = UInt64
120 }
121 
FlatBuffersVersion_2_0_0null122 public func FlatBuffersVersion_2_0_0() {}
123