forked from apple/swift-nio
/
ByteBuffer-foundation.swift
141 lines (126 loc) · 6.21 KB
/
ByteBuffer-foundation.swift
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
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
//===----------------------------------------------------------------------===//
//
// This source file is part of the SwiftNIO open source project
//
// Copyright (c) 2017-2018 Apple Inc. and the SwiftNIO project authors
// Licensed under Apache License v2.0
//
// See LICENSE.txt for license information
// See CONTRIBUTORS.txt for the list of SwiftNIO project authors
//
// SPDX-License-Identifier: Apache-2.0
//
//===----------------------------------------------------------------------===//
import NIO
import Foundation
/// Errors that may be thrown by ByteBuffer methods that call into Foundation.
public enum ByteBufferFoundationError: Error {
/// Attempting to encode the given string failed.
case failedToEncodeString
}
/*
* This is NIO's `NIOFoundationCompat` module which at the moment only adds `ByteBuffer` utility methods
* for Foundation's `Data` type.
*
* The reason that it's not in the `NIO` module is that we don't want to have any direct Foundation dependencies
* in `NIO` as Foundation is problematic for a few reasons:
*
* - its implementation is different on Linux and on macOS which means our macOS tests might be inaccurate
* - on macOS Foundation is mostly written in ObjC which means the autorelease pool might get populated
* - `swift-corelibs-foundation` (the OSS Foundation used on Linux) links the world which will prevent anyone from
* having static binaries. It can also cause problems in the choice of an SSL library as Foundation already brings
* the platforms OpenSSL in which might cause problems.
*/
extension ByteBuffer {
// MARK: Data APIs
/// Read `length` bytes off this `ByteBuffer`, move the reader index forward by `length` bytes and return the result
/// as `Data`.
///
/// - parameters:
/// - length: The number of bytes to be read from this `ByteBuffer`.
/// - returns: A `Data` value containing `length` bytes or `nil` if there aren't at least `length` bytes readable.
public mutating func readData(length: Int) -> Data? {
return self.getData(at: self.readerIndex, length: length).map {
self.moveReaderIndex(forwardBy: length)
return $0
}
}
/// Return `length` bytes starting at `index` and return the result as `Data`. This will not change the reader index.
/// The selected bytes must be readable or else `nil` will be returned.
///
/// - parameters:
/// - index: The starting index of the bytes of interest into the `ByteBuffer`
/// - length: The number of bytes of interest
/// - returns: A `Data` value containing the bytes of interest or `nil` if the selected bytes are not readable.
public func getData(at index0: Int, length: Int) -> Data? {
let index = index0 - self.readerIndex
guard index >= 0 && length >= 0 && index <= self.readableBytes - length else {
return nil
}
return self.withUnsafeReadableBytesWithStorageManagement { ptr, storageRef in
_ = storageRef.retain()
return Data(bytesNoCopy: UnsafeMutableRawPointer(mutating: ptr.baseAddress!.advanced(by: index)),
count: Int(length),
deallocator: .custom { _, _ in storageRef.release() })
}
}
/// Get a `String` decoding `length` bytes starting at `index` with `encoding`. This will not change the reader index.
/// The selected bytes must be readable or else `nil` will be returned.
///
/// - parameters:
/// - index: The starting index of the bytes of interest into the `ByteBuffer`.
/// - length: The number of bytes of interest.
/// - encoding: The `String` encoding to be used.
/// - returns: A `String` value containing the bytes of interest or `nil` if the selected bytes are not readable or
/// cannot be decoded with the given encoding.
public func getString(at index: Int, length: Int, encoding: String.Encoding) -> String? {
guard let data = self.getData(at: index, length: length) else {
return nil
}
return String(data: data, encoding: encoding)
}
/// Read a `String` decoding `length` bytes with `encoding` from the `readerIndex`, moving the `readerIndex` appropriately.
///
/// - parameters:
/// - length: The number of bytes to read.
/// - encoding: The `String` encoding to be used.
/// - returns: A `String` value containing the bytes of interest or `nil` if the `ByteBuffer` doesn't contain enough bytes, or
/// if those bytes cannot be decoded with the given encoding.
public mutating func readString(length: Int, encoding: String.Encoding) -> String? {
guard length <= self.readableBytes else {
return nil
}
guard let string = self.getString(at: self.readerIndex, length: length, encoding: encoding) else {
return nil
}
self.moveReaderIndex(forwardBy: length)
return string
}
/// Write `string` into this `ByteBuffer` using the encoding `encoding`, moving the writer index forward appropriately.
///
/// - parameters:
/// - string: The string to write.
/// - encoding: The encoding to use to encode the string.
/// - returns: The number of bytes written.
@discardableResult
public mutating func writeString(_ string: String, encoding: String.Encoding) throws -> Int {
let written = try self.setString(string, encoding: encoding, at: self.writerIndex)
self.moveWriterIndex(forwardBy: written)
return written
}
/// Write `string` into this `ByteBuffer` at `index` using the encoding `encoding`. Does not move the writer index.
///
/// - parameters:
/// - string: The string to write.
/// - encoding: The encoding to use to encode the string.
/// - index: The index for the first serialized byte.
/// - returns: The number of bytes written.
@discardableResult
public mutating func setString(_ string: String, encoding: String.Encoding, at index: Int) throws -> Int {
guard let data = string.data(using: encoding) else {
throw ByteBufferFoundationError.failedToEncodeString
}
return self.setBytes(data, at: index)
}
}
extension ByteBufferView: ContiguousBytes {}