averello/swift-mirror
1
0
Fork 0
mirror of https://github.com/apple/swift.git synced 2025-12-21 12:14:44 +01:00
Code Issues Packages Projects Releases Wiki Activity

[stdlib] Failable String inits from UTF8/16 views

Browse Source 
String.UTF8View and String.UTF16View may be slices that don't both start
and end on Unicode scalar boundaries, in which case conversion to a
String must fail.

Swift SVN r24669
This commit is contained in:
Dave Abrahams
2015-01-23 02:46:42 +00:00
parent 6d72340259
commit 02e70d15d1
4 changed files with 58 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files

23
stdlib/core/StringUTF16.swift
View File

@@ -165,9 +165,18 @@ extension String {
}
/// Construct the `String` corresponding to the given sequence of
/// UTF16 code units.
public init(_ utf16: UTF16View) {
self.init(utf16._core[utf16._offset..<utf16._offset+utf16._length])
/// UTF-16 code units. If `utf16` contains unpaired surrogates, the
/// result is `nil`.
public init?(_ utf16: UTF16View) {
let wholeString = String(utf16._core)
if let start = utf16.startIndex.samePositionIn(wholeString) {
if let end = utf16.endIndex.samePositionIn(wholeString) {
self = wholeString[start..<end]
return
}
}
return nil
}
/// The index type for subscripting a `String`\ 's `utf16` view.
@@ -242,7 +251,7 @@ extension String.UTF16View.Index {
/// `utf8Index`. If no such position exists, the result is `nil`.
///
/// Requires: `utf8Index` is an element of
/// `indices(String(utf16).utf8)`.
/// `indices(String(utf16)!.utf8)`.
public init?(
_ utf8Index: String.UTF8Index, within utf16: String.UTF16View
) {
@@ -263,7 +272,7 @@ extension String.UTF16View.Index {
/// `unicodeScalarIndex`.
///
/// Requires: `unicodeScalarIndex` is an element of
/// `indices(String(utf16).unicodeScalars)`.
/// `indices(String(utf16)!.unicodeScalars)`.
public init(
_ unicodeScalarIndex: String.UnicodeScalarIndex,
within utf16: String.UTF16View) {
@@ -274,7 +283,7 @@ extension String.UTF16View.Index {
/// `characterIndex`.
///
/// Requires: `characterIndex` is an element of
/// `indices(String(utf16))`.
/// `indices(String(utf16)!)`.
public init(_ characterIndex: String.Index, within utf16: String.UTF16View) {
_offset = characterIndex._utf16Index
}
@@ -283,7 +292,7 @@ extension String.UTF16View.Index {
/// to `self`, or if no such position exists, `nil`.
///
/// Requires: `self` is an element of
/// `indices(String(utf8).utf16)`.
/// `indices(String(utf8)!.utf16)`.
public func samePositionIn(
utf8: String.UTF8View
) -> String.UTF8View.Index? {