// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package subtle

import (
	"bytes";
	"testing";
	"testing/quick";
)

type TestConstantTimeCompareStruct struct {
	a, b	[]byte;
	out	int;
}

var testConstandTimeCompareData = []TestConstantTimeCompareStruct{
	TestConstantTimeCompareStruct{[]byte{}, []byte{}, 1},
	TestConstantTimeCompareStruct{[]byte{0x11}, []byte{0x11}, 1},
	TestConstantTimeCompareStruct{[]byte{0x12}, []byte{0x11}, 0},
}

func TestConstantTimeCompare(t *testing.T) {
	for i, test := range testConstandTimeCompareData {
		if r := ConstantTimeCompare(test.a, test.b); r != test.out {
			t.Errorf("#%d bad result (got %x, want %x)", i, r, test.out);
		}
	}
}

type TestConstantTimeByteEqStruct struct {
	a, b	uint8;
	out	int;
}

var testConstandTimeByteEqData = []TestConstantTimeByteEqStruct{
	TestConstantTimeByteEqStruct{0, 0, 1},
	TestConstantTimeByteEqStruct{0, 1, 0},
	TestConstantTimeByteEqStruct{1, 0, 0},
	TestConstantTimeByteEqStruct{0xff, 0xff, 1},
	TestConstantTimeByteEqStruct{0xff, 0xfe, 0},
}

func byteEq(a, b uint8) int {
	if a == b {
		return 1;
	}
	return 0;
}

func TestConstantTimeByteEq(t *testing.T) {
	for i, test := range testConstandTimeByteEqData {
		if r := ConstantTimeByteEq(test.a, test.b); r != test.out {
			t.Errorf("#%d bad result (got %x, want %x)", i, r, test.out);
		}
	}
	err := quick.CheckEqual(ConstantTimeByteEq, byteEq, nil);
	if err != nil {
		t.Error(err);
	}
}

func eq(a, b int32) int {
	if a == b {
		return 1;
	}
	return 0;
}

func TestConstantTimeEq(t *testing.T) {
	err := quick.CheckEqual(ConstantTimeEq, eq, nil);
	if err != nil {
		t.Error(err);
	}
}

func copy(v int, x, y []byte) []byte {
	if len(x) > len(y) {
		x = x[0:len(y)];
	} else {
		y = y[0:len(x)];
	}
	if v == 1 {
		bytes.Copy(x, y);
	}
	return x;
}

func constantTimeCopyWrapper(v int, x, y []byte) []byte {
	if len(x) > len(y) {
		x = x[0:len(y)];
	} else {
		y = y[0:len(x)];
	}
	v &= 1;
	ConstantTimeCopy(v, x, y);
	return x;
}

func TestConstantTimeCopy(t *testing.T) {
	err := quick.CheckEqual(constantTimeCopyWrapper, copy, nil);
	if err != nil {
		t.Error(err);
	}
}
