natives: duplicate aliasing.go in x/crypto revisted

benma · benma · commit f716f9988413 · 2023-08-28T16:18:54.000+02:00
Same as fcd349a. x/crypto internally moved the AnyOverlap from x/crypto/internal/subtle/ to /x/crypto/internal/alias/.
diff --git a/compiler/natives/src/crypto/internal/subtle/aliasing.go b/compiler/natives/src/crypto/internal/subtle/aliasing.go
@@ -4,8 +4,9 @@
 package subtle
 
 // This file duplicated is these two locations:
-// - src/crypto/internal/subtle/
-// - src/golang.org/x/crypto/internal/subtle/
+// - src/crypto/internal/subtle/aliasing.go
+// - src/golang.org/x/crypto/internal/subtle/aliasing.go
+// - src/golang.org/x/crypto/internal/alias/alias.go
 
 import "github.com/gopherjs/gopherjs/js"
 
diff --git a/compiler/natives/src/golang.org/x/crypto/internal/alias/alias.go b/compiler/natives/src/golang.org/x/crypto/internal/alias/alias.go
@@ -0,0 +1,21 @@
+//go:build js
+// +build js
+
+package alias
+
+// This file duplicated is these two locations:
+// - src/crypto/internal/subtle/aliasing.go
+// - src/golang.org/x/crypto/internal/subtle/aliasing.go
+// - src/golang.org/x/crypto/internal/alias/alias.go
+
+import "github.com/gopherjs/gopherjs/js"
+
+// AnyOverlap reports whether x and y share memory at any (not necessarily
+// corresponding) index. The memory beyond the slice length is ignored.
+func AnyOverlap(x, y []byte) bool {
+	// GopherJS: We can't rely on pointer arithmetic, so use GopherJS slice internals.
+	return len(x) > 0 && len(y) > 0 &&
+		js.InternalObject(x).Get("$array") == js.InternalObject(y).Get("$array") &&
+		js.InternalObject(x).Get("$offset").Int() <= js.InternalObject(y).Get("$offset").Int()+len(y)-1 &&
+		js.InternalObject(y).Get("$offset").Int() <= js.InternalObject(x).Get("$offset").Int()+len(x)-1
+}
diff --git a/compiler/natives/src/golang.org/x/crypto/internal/subtle/aliasing.go b/compiler/natives/src/golang.org/x/crypto/internal/subtle/aliasing.go
@@ -4,8 +4,9 @@
 package subtle
 
 // This file duplicated is these two locations:
-// - src/crypto/internal/subtle/
-// - src/golang.org/x/crypto/internal/subtle/
+// - src/crypto/internal/subtle/aliasing.go
+// - src/golang.org/x/crypto/internal/subtle/aliasing.go
+// - src/golang.org/x/crypto/internal/alias/alias.go
 
 import "github.com/gopherjs/gopherjs/js"
 
