Merge pull request #17636 from lancep/specialize_remaining

Lance Parker · web-flow · commit 78e9e9062b81 · 2018-07-02T11:16:45.000-07:00
[stdlib]Specialize `remaining` on _CollectionSource
diff --git a/stdlib/public/core/NormalizedCodeUnitIterator.swift b/stdlib/public/core/NormalizedCodeUnitIterator.swift
@@ -63,7 +63,11 @@ struct _NormalizedCodeUnitIterator: IteratorProtocol {
     where Source.Element == UInt16, Source.SubSequence == Source
   {
     var remaining: Int {
-      return collection.distance(from: index, to: collection.endIndex)
+      @_specialize(where Source == _UnmanagedString<UInt16>)
+      @_specialize(where Source == _UnmanagedOpaqueString)
+      get {
+        return collection.distance(from: index, to: collection.endIndex)
+      }
     }
     var collection: Source
     var index: Source.Index

Original file line number	Diff line number	Diff line change
`@@ -63,7 +63,11 @@ struct _NormalizedCodeUnitIterator: IteratorProtocol {`
`63`	`63`	`where Source.Element == UInt16, Source.SubSequence == Source`
`64`	`64`	`{`
`65`	`65`	`var remaining: Int {`
`66`		`- return collection.distance(from: index, to: collection.endIndex)`
	`66`	`+ @_specialize(where Source == _UnmanagedString<UInt16>)`
	`67`	`+ @_specialize(where Source == _UnmanagedOpaqueString)`
	`68`	`+ get {`
	`69`	`+ return collection.distance(from: index, to: collection.endIndex)`
	`70`	`+ }`
`67`	`71`	`}`
`68`	`72`	`var collection: Source`
`69`	`73`	`var index: Source.Index`