1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
|
import Foundation
enum Endianness {
case big
case little
}
extension Data {
func readUInt8(at offset: Int) -> UInt8? {
guard offset >= 0, offset + MemoryLayout<UInt8>.size <= self.count else {
return nil
}
return self[offset]
}
func readUInt16(at offset: Int, endianness: Endianness = .big) -> UInt16? {
guard offset >= 0, offset + MemoryLayout<UInt16>.size <= self.count else {
return nil
}
let value = self.subdata(in: offset..<(offset + MemoryLayout<UInt16>.size)).withUnsafeBytes { $0.load(as: UInt16.self) }
return (endianness == .big) ? value.bigEndian : value.littleEndian
}
func readUInt32(at offset: Int, endianness: Endianness = .big) -> UInt32? {
guard offset >= 0, offset + MemoryLayout<UInt32>.size <= self.count else {
return nil
}
let value = self.subdata(in: offset..<(offset + MemoryLayout<UInt32>.size)).withUnsafeBytes { $0.load(as: UInt32.self) }
return (endianness == .big) ? value.bigEndian : value.littleEndian
}
func readData(at offset: Int, length: Int) -> Data? {
guard offset >= 0, offset + length <= self.count else {
return nil
}
return self[offset..<(offset + length)]
}
func readString(at offset: Int, length: Int, encoding: String.Encoding) -> String? {
return String(data: self[offset..<(offset + length)], encoding: encoding)
}
mutating func appendUInt8(_ value: UInt8, endianness: Endianness = .big) {
var val = endianness == .big ? value.bigEndian : value.littleEndian
append(&val, count: MemoryLayout<UInt8>.size)
}
mutating func appendUInt16(_ value: UInt16, endianness: Endianness = .big) {
var val = endianness == .big ? value.bigEndian : value.littleEndian
Swift.withUnsafeBytes(of: &val) { buffer in
append(buffer.bindMemory(to: UInt8.self))
}
// append(&val, count: MemoryLayout<UInt16>.size)
}
mutating func appendUInt32(_ value: UInt32, endianness: Endianness = .big) {
var val = endianness == .big ? value.bigEndian : value.littleEndian
Swift.withUnsafeBytes(of: &val) { buffer in
append(buffer.bindMemory(to: UInt8.self))
}
// append(&val, count: MemoryLayout<UInt32>.size)
}
}
|
