Call internal impl directly

Author: milseman

stdlib/public/core/StringComparison.swift

@@ -97,7 +97,7 @@ internal func _stringCompareInternal(
 }
 
 @_effects(readonly)
-private func _stringCompareFastUTF8(
+internal func _stringCompareFastUTF8(
   _ utf8Left: UnsafeBufferPointer<UInt8>,
   _ utf8Right: UnsafeBufferPointer<UInt8>,
   expecting: _StringComparisonResult,

stdlib/public/core/UTF8Span.swift

@@ -166,23 +166,22 @@ extension UTF8Span {
 
 }
 
-
-func TODO(_ message: String) -> Never {
-  fatalError("TODO: \(message)")
+func UNSUPPORTED(_ message: String) -> Never {
+  fatalError("UNSUPPORTED: \(message)")
 }
 
 // TODO(toolchain): decide if we rebase on top of Guillaume's work
 @available(SwiftStdlib 6.1, *)
 extension String {
   public var utf8Span: UTF8Span {
-    TODO("Decide whether to rebase on top of Span PR or wait for merge")
+    UNSUPPORTED("utf8Span property pending compiler fixes")
   }
 }
 
 @available(SwiftStdlib 6.1, *)
 extension Substring {
   public var utf8Span: UTF8Span {
-    TODO("Decide whether to rebase on top of Span PR or wait for merge")
+    UNSUPPORTED("utf8Span property pending compiler fixes")
   }
 }
 

stdlib/public/core/UTF8SpanBits.swift

@@ -75,7 +75,7 @@ extension UTF8Span {
         if s.value < 0x300 {
           continue
         }
-        TODO("Refactor and adapt _StringGutsSlice._fastNFCCheck()")
+        UNSUPPORTED("NFC quick check (pending internal refactoring)")
       }
       self._countAndFlags |= Self._nfcBit
       return true

stdlib/public/core/UTF8SpanComparisons.swift

@@ -57,15 +57,31 @@ extension UTF8Span {
   public func isCanonicallyEquivalent(
     to other: UTF8Span
   ) -> Bool {
-    self._str == other._str
+    self._withUnsafeBufferPointer { selfBufPtr in
+      other._withUnsafeBufferPointer { otherBufPtr in
+        _stringCompareFastUTF8(
+          selfBufPtr,
+          otherBufPtr,
+          expecting: .equal,
+          bothNFC: self.isKnownNFC && other.isKnownNFC)
+      }
+    }
   }
 
-  /// Whether `self` orders less than `other` under Unicode Canonical 
+  /// Whether `self` orders less than `other` under Unicode Canonical
   /// Equivalence using normalized code-unit order (in NFC).
   public func isCanonicallyLessThan(
     _ other: UTF8Span
   ) -> Bool {
-    self._str < other._str
+    self._withUnsafeBufferPointer { selfBufPtr in
+      other._withUnsafeBufferPointer { otherBufPtr in
+        _stringCompareFastUTF8(
+          selfBufPtr,
+          otherBufPtr,
+          expecting: .less,
+          bothNFC: self.isKnownNFC && other.isKnownNFC)
+      }
+    }
   }
 }