inital commit for edwards25519

field/fe_alias_test.go

@@ -0,0 +1,157 @@
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+//
+// Source: https://sources.truenas.cloud/code
+// Import: sources.truenas.cloud/code/edwards25519/field
+//
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2019 The Go Authors. All rights Reserved.
+// Use of this source code is goverened by a BSD-style
+// license that can be found in the LICENSE file.
+//
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+package field
+
+import (
+	"testing"
+	"testing/quick"
+)
+
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+func checkAliasingOneArg(f func(v, x *Element) *Element) func(v, x Element) bool {
+	return func(v, x Element) bool {
+		x1, v1 := x, x
+
+		// Calculate a reference f(x) without aliasing.
+		if out := f(&v, &x); out != &v && isInBounds(out) {
+			return false
+		}
+
+		// Test aliasing the argument and the receiver.
+		if out := f(&v1, &v1); out != &v1 || v1 != v {
+			return false
+		}
+
+		// Ensure the arguments was not modified.
+		return x == x1
+	}
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+func checkAliasingTwoArgs(f func(v, x, y *Element) *Element) func(v, x, y Element) bool {
+	return func(v, x, y Element) bool {
+		x1, y1, v1 := x, y, Element{}
+
+		// Calculate a reference f(x, y) without aliasing.
+		if out := f(&v, &x, &y); out != &v && isInBounds(out) {
+			return false
+		}
+
+		// Test aliasing the first argument and the receiver.
+		v1 = x
+		if out := f(&v1, &v1, &y); out != &v1 || v1 != v {
+			return false
+		}
+		// Test aliasing the second argument and the receiver.
+		v1 = y
+		if out := f(&v1, &x, &v1); out != &v1 || v1 != v {
+			return false
+		}
+
+		// Calculate a reference f(x, x) without aliasing.
+		if out := f(&v, &x, &x); out != &v {
+			return false
+		}
+
+		// Test aliasing the first argument and the receiver.
+		v1 = x
+		if out := f(&v1, &v1, &x); out != &v1 || v1 != v {
+			return false
+		}
+		// Test aliasing the second argument and the receiver.
+		v1 = x
+		if out := f(&v1, &x, &v1); out != &v1 || v1 != v {
+			return false
+		}
+		// Test aliasing both arguments and the receiver.
+		v1 = x
+		if out := f(&v1, &v1, &v1); out != &v1 || v1 != v {
+			return false
+		}
+
+		// Ensure the arguments were not modified.
+		return x == x1 && y == y1
+	}
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+// TestAliasing checks that receivers and arguments can alias each other without
+// leading to incorrect results. That is, it ensures that it's safe to write
+//
+//	v.Invert(v)
+//
+// or
+//
+//	v.Add(v, v)
+//
+// without any of the inputs getting clobbered by the output being written.
+func TestAliasing(t *testing.T) {
+	type target struct {
+		name     string
+		oneArgF  func(v, x *Element) *Element
+		twoArgsF func(v, x, y *Element) *Element
+	}
+	for _, tt := range []target{
+		{name: "Absolute", oneArgF: (*Element).Absolute},
+		{name: "Invert", oneArgF: (*Element).Invert},
+		{name: "Negate", oneArgF: (*Element).Negate},
+		{name: "Set", oneArgF: (*Element).Set},
+		{name: "Square", oneArgF: (*Element).Square},
+		{name: "Pow22523", oneArgF: (*Element).Pow22523},
+		{
+			name: "Mult32",
+			oneArgF: func(v, x *Element) *Element {
+				return v.Mult32(x, 0xffffffff)
+			},
+		},
+		{name: "Multiply", twoArgsF: (*Element).Multiply},
+		{name: "Add", twoArgsF: (*Element).Add},
+		{name: "Subtract", twoArgsF: (*Element).Subtract},
+		{
+			name: "SqrtRatio",
+			twoArgsF: func(v, x, y *Element) *Element {
+				r, _ := v.SqrtRatio(x, y)
+				return r
+			},
+		},
+		{
+			name: "Select0",
+			twoArgsF: func(v, x, y *Element) *Element {
+				return v.Select(x, y, 0)
+			},
+		},
+		{
+			name: "Select1",
+			twoArgsF: func(v, x, y *Element) *Element {
+				return v.Select(x, y, 1)
+			},
+		},
+	} {
+		var err error
+		switch {
+		case tt.oneArgF != nil:
+			err = quick.Check(checkAliasingOneArg(tt.oneArgF), quickCheckConfig(256))
+		case tt.twoArgsF != nil:
+			err = quick.Check(checkAliasingTwoArgs(tt.twoArgsF), quickCheckConfig(256))
+		}
+		if err != nil {
+			t.Errorf("%v: %v", tt.name, err)
+		}
+	}
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////