// 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 asn1

import (
	"bytes"
	"encoding/hex"
	"fmt"
	"math"
	"math/big"
	"reflect"
	"strings"
	"testing"
	"time"
)

type boolTest struct {
	in  []byte
	ok  bool
	out bool
}

var boolTestData = []boolTest{
	{[]byte{0x00}, true, false},
	{[]byte{0xff}, true, true},
	{[]byte{0x00, 0x00}, false, false},
	{[]byte{0xff, 0xff}, false, false},
	{[]byte{0x01}, false, false},
}

func TestParseBool(t *testing.T) {
	for i, test := range boolTestData {
		ret, err := parseBool(test.in)
		if (err == nil) != test.ok {
			t.Errorf("#%d: Incorrect error result (did fail? %v, expected: %v)", i, err == nil, test.ok)
		}
		if test.ok && ret != test.out {
			t.Errorf("#%d: Bad result: %v (expected %v)", i, ret, test.out)
		}
	}
}

type int64Test struct {
	in  []byte
	ok  bool
	out int64
}

var int64TestData = []int64Test{
	{[]byte{0x00}, true, 0},
	{[]byte{0x7f}, true, 127},
	{[]byte{0x00, 0x80}, true, 128},
	{[]byte{0x01, 0x00}, true, 256},
	{[]byte{0x80}, true, -128},
	{[]byte{0xff, 0x7f}, true, -129},
	{[]byte{0xff}, true, -1},
	{[]byte{0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}, true, -9223372036854775808},
	{[]byte{0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}, false, 0},
	{[]byte{}, false, 0},
	{[]byte{0x00, 0x7f}, false, 0},
	{[]byte{0xff, 0xf0}, false, 0},
}

func TestParseInt64(t *testing.T) {
	for i, test := range int64TestData {
		ret, err := parseInt64(test.in)
		if (err == nil) != test.ok {
			t.Errorf("#%d: Incorrect error result (did fail? %v, expected: %v)", i, err == nil, test.ok)
		}
		if test.ok && ret != test.out {
			t.Errorf("#%d: Bad result: %v (expected %v)", i, ret, test.out)
		}
	}
}

type int32Test struct {
	in  []byte
	ok  bool
	out int32
}

var int32TestData = []int32Test{
	{[]byte{0x00}, true, 0},
	{[]byte{0x7f}, true, 127},
	{[]byte{0x00, 0x80}, true, 128},
	{[]byte{0x01, 0x00}, true, 256},
	{[]byte{0x80}, true, -128},
	{[]byte{0xff, 0x7f}, true, -129},
	{[]byte{0xff}, true, -1},
	{[]byte{0x80, 0x00, 0x00, 0x00}, true, -2147483648},
	{[]byte{0x80, 0x00, 0x00, 0x00, 0x00}, false, 0},
	{[]byte{}, false, 0},
	{[]byte{0x00, 0x7f}, false, 0},
	{[]byte{0xff, 0xf0}, false, 0},
}

func TestParseInt32(t *testing.T) {
	for i, test := range int32TestData {
		ret, err := parseInt32(test.in)
		if (err == nil) != test.ok {
			t.Errorf("#%d: Incorrect error result (did fail? %v, expected: %v)", i, err == nil, test.ok)
		}
		if test.ok && int32(ret) != test.out {
			t.Errorf("#%d: Bad result: %v (expected %v)", i, ret, test.out)
		}
	}
}

var bigIntTests = []struct {
	in     []byte
	ok     bool
	base10 string
}{
	{[]byte{0xff}, true, "-1"},
	{[]byte{0x00}, true, "0"},
	{[]byte{0x01}, true, "1"},
	{[]byte{0x00, 0xff}, true, "255"},
	{[]byte{0xff, 0x00}, true, "-256"},
	{[]byte{0x01, 0x00}, true, "256"},
	{[]byte{}, false, ""},
	{[]byte{0x00, 0x7f}, false, ""},
	{[]byte{0xff, 0xf0}, false, ""},
}

func TestParseBigInt(t *testing.T) {
	for i, test := range bigIntTests {
		ret, err := parseBigInt(test.in)
		if (err == nil) != test.ok {
			t.Errorf("#%d: Incorrect error result (did fail? %v, expected: %v)", i, err == nil, test.ok)
		}
		if test.ok {
			if ret.String() != test.base10 {
				t.Errorf("#%d: bad result from %x, got %s want %s", i, test.in, ret.String(), test.base10)
			}
			e, err := makeBigInt(ret)
			if err != nil {
				t.Errorf("%d: err=%q", i, err)
				continue
			}
			result := make([]byte, e.Len())
			e.Encode(result)
			if !bytes.Equal(result, test.in) {
				t.Errorf("#%d: got %x from marshaling %s, want %x", i, result, ret, test.in)
			}
		}
	}
}

type bitStringTest struct {
	in        []byte
	ok        bool
	out       []byte
	bitLength int
}

var bitStringTestData = []bitStringTest{
	{[]byte{}, false, []byte{}, 0},
	{[]byte{0x00}, true, []byte{}, 0},
	{[]byte{0x07, 0x00}, true, []byte{0x00}, 1},
	{[]byte{0x07, 0x01}, false, []byte{}, 0},
	{[]byte{0x07, 0x40}, false, []byte{}, 0},
	{[]byte{0x08, 0x00}, false, []byte{}, 0},
}

func TestBitString(t *testing.T) {
	for i, test := range bitStringTestData {
		ret, err := parseBitString(test.in)
		if (err == nil) != test.ok {
			t.Errorf("#%d: Incorrect error result (did fail? %v, expected: %v)", i, err == nil, test.ok)
		}
		if err == nil {
			if test.bitLength != ret.BitLength || !bytes.Equal(ret.Bytes, test.out) {
				t.Errorf("#%d: Bad result: %v (expected %v %v)", i, ret, test.out, test.bitLength)
			}
		}
	}
}

func TestBitStringAt(t *testing.T) {
	bs := BitString{[]byte{0x82, 0x40}, 16}
	if bs.At(0) != 1 {
		t.Error("#1: Failed")
	}
	if bs.At(1) != 0 {
		t.Error("#2: Failed")
	}
	if bs.At(6) != 1 {
		t.Error("#3: Failed")
	}
	if bs.At(9) != 1 {
		t.Error("#4: Failed")
	}
	if bs.At(-1) != 0 {
		t.Error("#5: Failed")
	}
	if bs.At(17) != 0 {
		t.Error("#6: Failed")
	}
}

type bitStringRightAlignTest struct {
	in    []byte
	inlen int
	out   []byte
}

var bitStringRightAlignTests = []bitStringRightAlignTest{
	{[]byte{0x80}, 1, []byte{0x01}},
	{[]byte{0x80, 0x80}, 9, []byte{0x01, 0x01}},
	{[]byte{}, 0, []byte{}},
	{[]byte{0xce}, 8, []byte{0xce}},
	{[]byte{0xce, 0x47}, 16, []byte{0xce, 0x47}},
	{[]byte{0x34, 0x50}, 12, []byte{0x03, 0x45}},
}

func TestBitStringRightAlign(t *testing.T) {
	for i, test := range bitStringRightAlignTests {
		bs := BitString{test.in, test.inlen}
		out := bs.RightAlign()
		if !bytes.Equal(out, test.out) {
			t.Errorf("#%d got: %x want: %x", i, out, test.out)
		}
	}
}

type objectIdentifierTest struct {
	in  []byte
	ok  bool
	out ObjectIdentifier // has base type[]int
}

var objectIdentifierTestData = []objectIdentifierTest{
	{[]byte{}, false, []int{}},
	{[]byte{85}, true, []int{2, 5}},
	{[]byte{85, 0x02}, true, []int{2, 5, 2}},
	{[]byte{85, 0x02, 0xc0, 0x00}, true, []int{2, 5, 2, 0x2000}},
	{[]byte{0x81, 0x34, 0x03}, true, []int{2, 100, 3}},
	{[]byte{85, 0x02, 0xc0, 0x80, 0x80, 0x80, 0x80}, false, []int{}},
}

func TestObjectIdentifier(t *testing.T) {
	for i, test := range objectIdentifierTestData {
		ret, err := parseObjectIdentifier(test.in)
		if (err == nil) != test.ok {
			t.Errorf("#%d: Incorrect error result (did fail? %v, expected: %v)", i, err == nil, test.ok)
		}
		if err == nil {
			if !reflect.DeepEqual(test.out, ret) {
				t.Errorf("#%d: Bad result: %v (expected %v)", i, ret, test.out)
			}
		}
	}

	if s := ObjectIdentifier([]int{1, 2, 3, 4}).String(); s != "1.2.3.4" {
		t.Errorf("bad ObjectIdentifier.String(). Got %s, want 1.2.3.4", s)
	}
}

type timeTest struct {
	in  string
	ok  bool
	out time.Time
}

var utcTestData = []timeTest{
	{"910506164540-0700", true, time.Date(1991, 05, 06, 16, 45, 40, 0, time.FixedZone("", -7*60*60))},
	{"910506164540+0730", true, time.Date(1991, 05, 06, 16, 45, 40, 0, time.FixedZone("", 7*60*60+30*60))},
	{"910506234540Z", true, time.Date(1991, 05, 06, 23, 45, 40, 0, time.UTC)},
	{"9105062345Z", true, time.Date(1991, 05, 06, 23, 45, 0, 0, time.UTC)},
	{"5105062345Z", true, time.Date(1951, 05, 06, 23, 45, 0, 0, time.UTC)},
	{"a10506234540Z", false, time.Time{}},
	{"91a506234540Z", false, time.Time{}},
	{"9105a6234540Z", false, time.Time{}},
	{"910506a34540Z", false, time.Time{}},
	{"910506334a40Z", false, time.Time{}},
	{"91050633444aZ", false, time.Time{}},
	{"910506334461Z", false, time.Time{}},
	{"910506334400Za", false, time.Time{}},
	/* These are invalid times. However, the time package normalises times
	 * and they were accepted in some versions. See #11134. */
	{"000100000000Z", false, time.Time{}},
	{"101302030405Z", false, time.Time{}},
	{"100002030405Z", false, time.Time{}},
	{"100100030405Z", false, time.Time{}},
	{"100132030405Z", false, time.Time{}},
	{"100231030405Z", false, time.Time{}},
	{"100102240405Z", false, time.Time{}},
	{"100102036005Z", false, time.Time{}},
	{"100102030460Z", false, time.Time{}},
	{"-100102030410Z", false, time.Time{}},
	{"10-0102030410Z", false, time.Time{}},
	{"10-0002030410Z", false, time.Time{}},
	{"1001-02030410Z", false, time.Time{}},
	{"100102-030410Z", false, time.Time{}},
	{"10010203-0410Z", false, time.Time{}},
	{"1001020304-10Z", false, time.Time{}},
}

func TestUTCTime(t *testing.T) {
	for i, test := range utcTestData {
		ret, err := parseUTCTime([]byte(test.in))
		if err != nil {
			if test.ok {
				t.Errorf("#%d: parseUTCTime(%q) = error %v", i, test.in, err)
			}
			continue
		}
		if !test.ok {
			t.Errorf("#%d: parseUTCTime(%q) succeeded, should have failed", i, test.in)
			continue
		}
		const format = "Jan _2 15:04:05 -0700 2006" // ignore zone name, just offset
		have := ret.Format(format)
		want := test.out.Format(format)
		if have != want {
			t.Errorf("#%d: parseUTCTime(%q) = %s, want %s", i, test.in, have, want)
		}
	}
}

var generalizedTimeTestData = []timeTest{
	{"20100102030405Z", true, time.Date(2010, 01, 02, 03, 04, 05, 0, time.UTC)},
	{"20100102030405", false, time.Time{}},
	{"20100102030405+0607", true, time.Date(2010, 01, 02, 03, 04, 05, 0, time.FixedZone("", 6*60*60+7*60))},
	{"20100102030405-0607", true, time.Date(2010, 01, 02, 03, 04, 05, 0, time.FixedZone("", -6*60*60-7*60))},
	/* These are invalid times. However, the time package normalises times
	 * and they were accepted in some versions. See #11134. */
	{"00000100000000Z", false, time.Time{}},
	{"20101302030405Z", false, time.Time{}},
	{"20100002030405Z", false, time.Time{}},
	{"20100100030405Z", false, time.Time{}},
	{"20100132030405Z", false, time.Time{}},
	{"20100231030405Z", false, time.Time{}},
	{"20100102240405Z", false, time.Time{}},
	{"20100102036005Z", false, time.Time{}},
	{"20100102030460Z", false, time.Time{}},
	{"-20100102030410Z", false, time.Time{}},
	{"2010-0102030410Z", false, time.Time{}},
	{"2010-0002030410Z", false, time.Time{}},
	{"201001-02030410Z", false, time.Time{}},
	{"20100102-030410Z", false, time.Time{}},
	{"2010010203-0410Z", false, time.Time{}},
	{"201001020304-10Z", false, time.Time{}},
}

func TestGeneralizedTime(t *testing.T) {
	for i, test := range generalizedTimeTestData {
		ret, err := parseGeneralizedTime([]byte(test.in))
		if (err == nil) != test.ok {
			t.Errorf("#%d: Incorrect error result (did fail? %v, expected: %v)", i, err == nil, test.ok)
		}
		if err == nil {
			if !reflect.DeepEqual(test.out, ret) {
				t.Errorf("#%d: Bad result: %q → %v (expected %v)", i, test.in, ret, test.out)
			}
		}
	}
}

type tagAndLengthTest struct {
	in  []byte
	ok  bool
	out tagAndLength
}

var tagAndLengthData = []tagAndLengthTest{
	{[]byte{0x80, 0x01}, true, tagAndLength{2, 0, 1, false}},
	{[]byte{0xa0, 0x01}, true, tagAndLength{2, 0, 1, true}},
	{[]byte{0x02, 0x00}, true, tagAndLength{0, 2, 0, false}},
	{[]byte{0xfe, 0x00}, true, tagAndLength{3, 30, 0, true}},
	{[]byte{0x1f, 0x1f, 0x00}, true, tagAndLength{0, 31, 0, false}},
	{[]byte{0x1f, 0x81, 0x00, 0x00}, true, tagAndLength{0, 128, 0, false}},
	{[]byte{0x1f, 0x81, 0x80, 0x01, 0x00}, true, tagAndLength{0, 0x4001, 0, false}},
	{[]byte{0x00, 0x81, 0x80}, true, tagAndLength{0, 0, 128, false}},
	{[]byte{0x00, 0x82, 0x01, 0x00}, true, tagAndLength{0, 0, 256, false}},
	{[]byte{0x00, 0x83, 0x01, 0x00}, false, tagAndLength{}},
	{[]byte{0x1f, 0x85}, false, tagAndLength{}},
	{[]byte{0x30, 0x80}, false, tagAndLength{}},
	// Superfluous zeros in the length should be an error.
	{[]byte{0xa0, 0x82, 0x00, 0xff}, false, tagAndLength{}},
	// Lengths up to the maximum size of an int should work.
	{[]byte{0xa0, 0x84, 0x7f, 0xff, 0xff, 0xff}, true, tagAndLength{2, 0, 0x7fffffff, true}},
	// Lengths that would overflow an int should be rejected.
	{[]byte{0xa0, 0x84, 0x80, 0x00, 0x00, 0x00}, false, tagAndLength{}},
	// Long length form may not be used for lengths that fit in short form.
	{[]byte{0xa0, 0x81, 0x7f}, false, tagAndLength{}},
	// Tag numbers which would overflow int32 are rejected. (The value below is 2^31.)
	{[]byte{0x1f, 0x88, 0x80, 0x80, 0x80, 0x00, 0x00}, false, tagAndLength{}},
	// Tag numbers that fit in an int32 are valid. (The value below is 2^31 - 1.)
	{[]byte{0x1f, 0x87, 0xFF, 0xFF, 0xFF, 0x7F, 0x00}, true, tagAndLength{tag: math.MaxInt32}},
	// Long tag number form may not be used for tags that fit in short form.
	{[]byte{0x1f, 0x1e, 0x00}, false, tagAndLength{}},
}

func TestParseTagAndLength(t *testing.T) {
	for i, test := range tagAndLengthData {
		tagAndLength, _, err := parseTagAndLength(test.in, 0)
		if (err == nil) != test.ok {
			t.Errorf("#%d: Incorrect error result (did pass? %v, expected: %v)", i, err == nil, test.ok)
		}
		if err == nil && !reflect.DeepEqual(test.out, tagAndLength) {
			t.Errorf("#%d: Bad result: %v (expected %v)", i, tagAndLength, test.out)
		}
	}
}

type parseFieldParametersTest struct {
	in  string
	out fieldParameters
}

func newInt(n int) *int { return &n }

func newInt64(n int64) *int64 { return &n }

func newString(s string) *string { return &s }

func newBool(b bool) *bool { return &b }

var parseFieldParametersTestData []parseFieldParametersTest = []parseFieldParametersTest{
	{"", fieldParameters{}},
	{"ia5", fieldParameters{stringType: TagIA5String}},
	{"generalized", fieldParameters{timeType: TagGeneralizedTime}},
	{"utc", fieldParameters{timeType: TagUTCTime}},
	{"printable", fieldParameters{stringType: TagPrintableString}},
	{"numeric", fieldParameters{stringType: TagNumericString}},
	{"optional", fieldParameters{optional: true}},
	{"explicit", fieldParameters{explicit: true, tag: new(int)}},
	{"application", fieldParameters{application: true, tag: new(int)}},
	{"private", fieldParameters{private: true, tag: new(int)}},
	{"optional,explicit", fieldParameters{optional: true, explicit: true, tag: new(int)}},
	{"default:42", fieldParameters{defaultValue: newInt64(42)}},
	{"tag:17", fieldParameters{tag: newInt(17)}},
	{"optional,explicit,default:42,tag:17", fieldParameters{optional: true, explicit: true, defaultValue: newInt64(42), tag: newInt(17)}},
	{"optional,explicit,default:42,tag:17,rubbish1", fieldParameters{optional: true, explicit: true, application: false, defaultValue: newInt64(42), tag: newInt(17), stringType: 0, timeType: 0, set: false, omitEmpty: false}},
	{"set", fieldParameters{set: true}},
}

func TestParseFieldParameters(t *testing.T) {
	for i, test := range parseFieldParametersTestData {
		f := parseFieldParameters(test.in)
		if !reflect.DeepEqual(f, test.out) {
			t.Errorf("#%d: Bad result: %v (expected %v)", i, f, test.out)
		}
	}
}

type TestObjectIdentifierStruct struct {
	OID ObjectIdentifier
}

type TestContextSpecificTags struct {
	A int `asn1:"tag:1"`
}

type TestContextSpecificTags2 struct {
	A int `asn1:"explicit,tag:1"`
	B int
}

type TestContextSpecificTags3 struct {
	S string `asn1:"tag:1,utf8"`
}

type TestElementsAfterString struct {
	S    string
	A, B int
}

type TestBigInt struct {
	X *big.Int
}

type TestSet struct {
	Ints []int `asn1:"set"`
}

var unmarshalTestData = []struct {
	in  []byte
	out interface{}
}{
	{[]byte{0x02, 0x01, 0x42}, newInt(0x42)},
	{[]byte{0x05, 0x00}, &RawValue{0, 5, false, []byte{}, []byte{0x05, 0x00}}},
	{[]byte{0x30, 0x08, 0x06, 0x06, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d}, &TestObjectIdentifierStruct{[]int{1, 2, 840, 113549}}},
	{[]byte{0x03, 0x04, 0x06, 0x6e, 0x5d, 0xc0}, &BitString{[]byte{110, 93, 192}, 18}},
	{[]byte{0x30, 0x09, 0x02, 0x01, 0x01, 0x02, 0x01, 0x02, 0x02, 0x01, 0x03}, &[]int{1, 2, 3}},
	{[]byte{0x02, 0x01, 0x10}, newInt(16)},
	{[]byte{0x13, 0x04, 't', 'e', 's', 't'}, newString("test")},
	{[]byte{0x16, 0x04, 't', 'e', 's', 't'}, newString("test")},
	// Ampersand is allowed in PrintableString due to mistakes by major CAs.
	{[]byte{0x13, 0x05, 't', 'e', 's', 't', '&'}, newString("test&")},
	{[]byte{0x16, 0x04, 't', 'e', 's', 't'}, &RawValue{0, 22, false, []byte("test"), []byte("\x16\x04test")}},
	{[]byte{0x04, 0x04, 1, 2, 3, 4}, &RawValue{0, 4, false, []byte{1, 2, 3, 4}, []byte{4, 4, 1, 2, 3, 4}}},
	{[]byte{0x30, 0x03, 0x81, 0x01, 0x01}, &TestContextSpecificTags{1}},
	{[]byte{0x30, 0x08, 0xa1, 0x03, 0x02, 0x01, 0x01, 0x02, 0x01, 0x02}, &TestContextSpecificTags2{1, 2}},
	{[]byte{0x30, 0x03, 0x81, 0x01, '@'}, &TestContextSpecificTags3{"@"}},
	{[]byte{0x01, 0x01, 0x00}, newBool(false)},
	{[]byte{0x01, 0x01, 0xff}, newBool(true)},
	{[]byte{0x30, 0x0b, 0x13, 0x03, 0x66, 0x6f, 0x6f, 0x02, 0x01, 0x22, 0x02, 0x01, 0x33}, &TestElementsAfterString{"foo", 0x22, 0x33}},
	{[]byte{0x30, 0x05, 0x02, 0x03, 0x12, 0x34, 0x56}, &TestBigInt{big.NewInt(0x123456)}},
	{[]byte{0x30, 0x0b, 0x31, 0x09, 0x02, 0x01, 0x01, 0x02, 0x01, 0x02, 0x02, 0x01, 0x03}, &TestSet{Ints: []int{1, 2, 3}}},
	{[]byte{0x12, 0x0b, '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', ' '}, newString("0123456789 ")},
}

func TestUnmarshal(t *testing.T) {
	for i, test := range unmarshalTestData {
		pv := reflect.New(reflect.TypeOf(test.out).Elem())
		val := pv.Interface()
		_, err := Unmarshal(test.in, val)
		if err != nil {
			t.Errorf("Unmarshal failed at index %d %v", i, err)
		}
		if !reflect.DeepEqual(val, test.out) {
			t.Errorf("#%d:\nhave %#v\nwant %#v", i, val, test.out)
		}
	}
}

func TestUnmarshalWithNilOrNonPointer(t *testing.T) {
	tests := []struct {
		b    []byte
		v    interface{}
		want string
	}{
		{b: []byte{0x05, 0x00}, v: nil, want: "asn1: Unmarshal recipient value is nil"},
		{b: []byte{0x05, 0x00}, v: RawValue{}, want: "asn1: Unmarshal recipient value is non-pointer asn1.RawValue"},
		{b: []byte{0x05, 0x00}, v: (*RawValue)(nil), want: "asn1: Unmarshal recipient value is nil *asn1.RawValue"},
	}

	for _, test := range tests {
		_, err := Unmarshal(test.b, test.v)
		if err == nil {
			t.Errorf("Unmarshal expecting error, got nil")
			continue
		}
		if g, w := err.Error(), test.want; g != w {
			t.Errorf("InvalidUnmarshalError mismatch\nGot:  %q\nWant: %q", g, w)
		}
	}
}

type Certificate struct {
	TBSCertificate     TBSCertificate
	SignatureAlgorithm AlgorithmIdentifier
	SignatureValue     BitString
}

type TBSCertificate struct {
	Version            int `asn1:"optional,explicit,default:0,tag:0"`
	SerialNumber       RawValue
	SignatureAlgorithm AlgorithmIdentifier
	Issuer             RDNSequence
	Validity           Validity
	Subject            RDNSequence
	PublicKey          PublicKeyInfo
}

type AlgorithmIdentifier struct {
	Algorithm ObjectIdentifier
}

type RDNSequence []RelativeDistinguishedNameSET

type RelativeDistinguishedNameSET []AttributeTypeAndValue

type AttributeTypeAndValue struct {
	Type  ObjectIdentifier
	Value interface{}
}

type Validity struct {
	NotBefore, NotAfter time.Time
}

type PublicKeyInfo struct {
	Algorithm AlgorithmIdentifier
	PublicKey BitString
}

func TestCertificate(t *testing.T) {
	// This is a minimal, self-signed certificate that should parse correctly.
	var cert Certificate
	if _, err := Unmarshal(derEncodedSelfSignedCertBytes, &cert); err != nil {
		t.Errorf("Unmarshal failed: %v", err)
	}
	if !reflect.DeepEqual(cert, derEncodedSelfSignedCert) {
		t.Errorf("Bad result:\ngot: %+v\nwant: %+v", cert, derEncodedSelfSignedCert)
	}
}

func TestCertificateWithNUL(t *testing.T) {
	// This is the paypal NUL-hack certificate. It should fail to parse because
	// NUL isn't a permitted character in a PrintableString.

	var cert Certificate
	if _, err := Unmarshal(derEncodedPaypalNULCertBytes, &cert); err == nil {
		// allow for permissive parsing
		// t.Error("Unmarshal succeeded, should not have")
	}
}

type rawStructTest struct {
	Raw RawContent
	A   int
}

func TestRawStructs(t *testing.T) {
	var s rawStructTest
	input := []byte{0x30, 0x03, 0x02, 0x01, 0x50}

	rest, err := Unmarshal(input, &s)
	if len(rest) != 0 {
		t.Errorf("incomplete parse: %x", rest)
		return
	}
	if err != nil {
		t.Error(err)
		return
	}
	if s.A != 0x50 {
		t.Errorf("bad value for A: got %d want %d", s.A, 0x50)
	}
	if !bytes.Equal([]byte(s.Raw), input) {
		t.Errorf("bad value for Raw: got %x want %x", s.Raw, input)
	}
}

type oiEqualTest struct {
	first  ObjectIdentifier
	second ObjectIdentifier
	same   bool
}

var oiEqualTests = []oiEqualTest{
	{
		ObjectIdentifier{1, 2, 3},
		ObjectIdentifier{1, 2, 3},
		true,
	},
	{
		ObjectIdentifier{1},
		ObjectIdentifier{1, 2, 3},
		false,
	},
	{
		ObjectIdentifier{1, 2, 3},
		ObjectIdentifier{10, 11, 12},
		false,
	},
}

func TestObjectIdentifierEqual(t *testing.T) {
	for _, o := range oiEqualTests {
		if s := o.first.Equal(o.second); s != o.same {
			t.Errorf("ObjectIdentifier.Equal: got: %t want: %t", s, o.same)
		}
	}
}

var derEncodedSelfSignedCert = Certificate{
	TBSCertificate: TBSCertificate{
		Version:            0,
		SerialNumber:       RawValue{Class: 0, Tag: 2, IsCompound: false, Bytes: []uint8{0x0, 0x8c, 0xc3, 0x37, 0x92, 0x10, 0xec, 0x2c, 0x98}, FullBytes: []byte{2, 9, 0x0, 0x8c, 0xc3, 0x37, 0x92, 0x10, 0xec, 0x2c, 0x98}},
		SignatureAlgorithm: AlgorithmIdentifier{Algorithm: ObjectIdentifier{1, 2, 840, 113549, 1, 1, 5}},
		Issuer: RDNSequence{
			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 6}, Value: "XX"}},
			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 8}, Value: "Some-State"}},
			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 7}, Value: "City"}},
			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 10}, Value: "Internet Widgits Pty Ltd"}},
			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 3}, Value: "false.example.com"}},
			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{1, 2, 840, 113549, 1, 9, 1}, Value: "false@example.com"}},
		},
		Validity: Validity{
			NotBefore: time.Date(2009, 10, 8, 00, 25, 53, 0, time.UTC),
			NotAfter:  time.Date(2010, 10, 8, 00, 25, 53, 0, time.UTC),
		},
		Subject: RDNSequence{
			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 6}, Value: "XX"}},
			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 8}, Value: "Some-State"}},
			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 7}, Value: "City"}},
			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 10}, Value: "Internet Widgits Pty Ltd"}},
			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 3}, Value: "false.example.com"}},
			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{1, 2, 840, 113549, 1, 9, 1}, Value: "false@example.com"}},
		},
		PublicKey: PublicKeyInfo{
			Algorithm: AlgorithmIdentifier{Algorithm: ObjectIdentifier{1, 2, 840, 113549, 1, 1, 1}},
			PublicKey: BitString{
				Bytes: []uint8{
					0x30, 0x48, 0x2, 0x41, 0x0, 0xcd, 0xb7,
					0x63, 0x9c, 0x32, 0x78, 0xf0, 0x6, 0xaa, 0x27, 0x7f, 0x6e, 0xaf, 0x42,
					0x90, 0x2b, 0x59, 0x2d, 0x8c, 0xbc, 0xbe, 0x38, 0xa1, 0xc9, 0x2b, 0xa4,
					0x69, 0x5a, 0x33, 0x1b, 0x1d, 0xea, 0xde, 0xad, 0xd8, 0xe9, 0xa5, 0xc2,
					0x7e, 0x8c, 0x4c, 0x2f, 0xd0, 0xa8, 0x88, 0x96, 0x57, 0x72, 0x2a, 0x4f,
					0x2a, 0xf7, 0x58, 0x9c, 0xf2, 0xc7, 0x70, 0x45, 0xdc, 0x8f, 0xde, 0xec,
					0x35, 0x7d, 0x2, 0x3, 0x1, 0x0, 0x1,
				},
				BitLength: 592,
			},
		},
	},
	SignatureAlgorithm: AlgorithmIdentifier{Algorithm: ObjectIdentifier{1, 2, 840, 113549, 1, 1, 5}},
	SignatureValue: BitString{
		Bytes: []uint8{
			0xa6, 0x7b, 0x6, 0xec, 0x5e, 0xce,
			0x92, 0x77, 0x2c, 0xa4, 0x13, 0xcb, 0xa3, 0xca, 0x12, 0x56, 0x8f, 0xdc, 0x6c,
			0x7b, 0x45, 0x11, 0xcd, 0x40, 0xa7, 0xf6, 0x59, 0x98, 0x4, 0x2, 0xdf, 0x2b,
			0x99, 0x8b, 0xb9, 0xa4, 0xa8, 0xcb, 0xeb, 0x34, 0xc0, 0xf0, 0xa7, 0x8c, 0xf8,
			0xd9, 0x1e, 0xde, 0x14, 0xa5, 0xed, 0x76, 0xbf, 0x11, 0x6f, 0xe3, 0x60, 0xaa,
			0xfa, 0x88, 0x21, 0x49, 0x4, 0x35,
		},
		BitLength: 512,
	},
}

var derEncodedSelfSignedCertBytes = []byte{
	0x30, 0x82, 0x02, 0x18, 0x30,
	0x82, 0x01, 0xc2, 0x02, 0x09, 0x00, 0x8c, 0xc3, 0x37, 0x92, 0x10, 0xec, 0x2c,
	0x98, 0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01,
	0x05, 0x05, 0x00, 0x30, 0x81, 0x92, 0x31, 0x0b, 0x30, 0x09, 0x06, 0x03, 0x55,
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	0xbc, 0xbe, 0x38, 0xa1, 0xc9, 0x2b, 0xa4, 0x69, 0x5a, 0x33, 0x1b, 0x1d, 0xea,
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	0x04, 0x35,
}

var derEncodedPaypalNULCertBytes = []byte{
	0x30, 0x82, 0x06, 0x44, 0x30,
	0x82, 0x05, 0xad, 0xa0, 0x03, 0x02, 0x01, 0x02, 0x02, 0x03, 0x00, 0xf0, 0x9b,
	0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x05,
	0x05, 0x00, 0x30, 0x82, 0x01, 0x12, 0x31, 0x0b, 0x30, 0x09, 0x06, 0x03, 0x55,
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}

var stringSliceTestData = [][]string{
	{"foo", "bar"},
	{"foo", "\\bar"},
	{"foo", "\"bar\""},
	{"foo", "åäö"},
}

func TestStringSlice(t *testing.T) {
	for _, test := range stringSliceTestData {
		bs, err := Marshal(test)
		if err != nil {
			t.Error(err)
		}

		var res []string
		_, err = Unmarshal(bs, &res)
		if err != nil {
			t.Error(err)
		}

		if fmt.Sprintf("%v", res) != fmt.Sprintf("%v", test) {
			t.Errorf("incorrect marshal/unmarshal; %v != %v", res, test)
		}
	}
}

type explicitTaggedTimeTest struct {
	Time time.Time `asn1:"explicit,tag:0"`
}

var explicitTaggedTimeTestData = []struct {
	in  []byte
	out explicitTaggedTimeTest
}{
	{[]byte{0x30, 0x11, 0xa0, 0xf, 0x17, 0xd, '9', '1', '0', '5', '0', '6', '1', '6', '4', '5', '4', '0', 'Z'},
		explicitTaggedTimeTest{time.Date(1991, 05, 06, 16, 45, 40, 0, time.UTC)}},
	{[]byte{0x30, 0x17, 0xa0, 0xf, 0x18, 0x13, '2', '0', '1', '0', '0', '1', '0', '2', '0', '3', '0', '4', '0', '5', '+', '0', '6', '0', '7'},
		explicitTaggedTimeTest{time.Date(2010, 01, 02, 03, 04, 05, 0, time.FixedZone("", 6*60*60+7*60))}},
}

func TestExplicitTaggedTime(t *testing.T) {
	// Test that a time.Time will match either tagUTCTime or
	// tagGeneralizedTime.
	for i, test := range explicitTaggedTimeTestData {
		var got explicitTaggedTimeTest
		_, err := Unmarshal(test.in, &got)
		if err != nil {
			t.Errorf("Unmarshal failed at index %d %v", i, err)
		}
		if !got.Time.Equal(test.out.Time) {
			t.Errorf("#%d: got %v, want %v", i, got.Time, test.out.Time)
		}
	}
}

type implicitTaggedTimeTest struct {
	Time time.Time `asn1:"tag:24"`
}

func TestImplicitTaggedTime(t *testing.T) {
	// An implicitly tagged time value, that happens to have an implicit
	// tag equal to a GENERALIZEDTIME, should still be parsed as a UTCTime.
	// (There's no "timeType" in fieldParameters to determine what type of
	// time should be expected when implicitly tagged.)
	der := []byte{0x30, 0x0f, 0x80 | 24, 0xd, '9', '1', '0', '5', '0', '6', '1', '6', '4', '5', '4', '0', 'Z'}
	var result implicitTaggedTimeTest
	if _, err := Unmarshal(der, &result); err != nil {
		t.Fatalf("Error while parsing: %s", err)
	}
	if expected := time.Date(1991, 05, 06, 16, 45, 40, 0, time.UTC); !result.Time.Equal(expected) {
		t.Errorf("Wrong result. Got %v, want %v", result.Time, expected)
	}
}

type truncatedExplicitTagTest struct {
	Test int `asn1:"explicit,tag:0"`
}

func TestTruncatedExplicitTag(t *testing.T) {
	// This crashed Unmarshal in the past. See #11154.
	der := []byte{
		0x30, // SEQUENCE
		0x02, // two bytes long
		0xa0, // context-specific, tag 0
		0x30, // 48 bytes long
	}

	var result truncatedExplicitTagTest
	if _, err := Unmarshal(der, &result); err == nil {
		t.Error("Unmarshal returned without error")
	}
}

type invalidUTF8Test struct {
	Str string `asn1:"utf8"`
}

func TestUnmarshalInvalidUTF8(t *testing.T) {
	data := []byte("0\x05\f\x03a\xc9c")
	var result invalidUTF8Test
	_, err := Unmarshal(data, &result)

	const expectedSubstring = "UTF"
	if err == nil {
		t.Fatal("Successfully unmarshaled invalid UTF-8 data")
	} else if !strings.Contains(err.Error(), expectedSubstring) {
		t.Fatalf("Expected error to mention %q but error was %q", expectedSubstring, err.Error())
	}
}

func TestMarshalNilValue(t *testing.T) {
	nilValueTestData := []interface{}{
		nil,
		struct{ V interface{} }{},
	}
	for i, test := range nilValueTestData {
		if _, err := Marshal(test); err == nil {
			t.Fatalf("#%d: successfully marshaled nil value", i)
		}
	}
}

type unexported struct {
	X int
	y int
}

type exported struct {
	X int
	Y int
}

func TestUnexportedStructField(t *testing.T) {
	want := StructuralError{"struct contains unexported fields"}

	_, err := Marshal(unexported{X: 5, y: 1})
	if err != want {
		t.Errorf("got %v, want %v", err, want)
	}

	bs, err := Marshal(exported{X: 5, Y: 1})
	if err != nil {
		t.Fatal(err)
	}
	var u unexported
	_, err = Unmarshal(bs, &u)
	if err != want {
		t.Errorf("got %v, want %v", err, want)
	}
}

func TestNull(t *testing.T) {
	marshaled, err := Marshal(NullRawValue)
	if err != nil {
		t.Fatal(err)
	}
	if !bytes.Equal(NullBytes, marshaled) {
		t.Errorf("Expected Marshal of NullRawValue to yield %x, got %x", NullBytes, marshaled)
	}

	unmarshaled := RawValue{}
	if _, err := Unmarshal(NullBytes, &unmarshaled); err != nil {
		t.Fatal(err)
	}

	unmarshaled.FullBytes = NullRawValue.FullBytes
	if len(unmarshaled.Bytes) == 0 {
		// DeepEqual considers a nil slice and an empty slice to be different.
		unmarshaled.Bytes = NullRawValue.Bytes
	}

	if !reflect.DeepEqual(NullRawValue, unmarshaled) {
		t.Errorf("Expected Unmarshal of NullBytes to yield %v, got %v", NullRawValue, unmarshaled)
	}
}

func TestExplicitTagRawValueStruct(t *testing.T) {
	type foo struct {
		A RawValue `asn1:"optional,explicit,tag:5"`
		B []byte   `asn1:"optional,explicit,tag:6"`
	}
	before := foo{B: []byte{1, 2, 3}}
	derBytes, err := Marshal(before)
	if err != nil {
		t.Fatal(err)
	}

	var after foo
	if rest, err := Unmarshal(derBytes, &after); err != nil || len(rest) != 0 {
		t.Fatal(err)
	}

	got := fmt.Sprintf("%#v", after)
	want := fmt.Sprintf("%#v", before)
	if got != want {
		t.Errorf("got %s, want %s (DER: %x)", got, want, derBytes)
	}
}

func TestTaggedRawValue(t *testing.T) {
	type taggedRawValue struct {
		A RawValue `asn1:"tag:5"`
	}
	type untaggedRawValue struct {
		A RawValue
	}
	const isCompound = 0x20
	const tag = 5

	tests := []struct {
		shouldMatch bool
		derBytes    []byte
	}{
		{false, []byte{0x30, 3, TagInteger, 1, 1}},
		{true, []byte{0x30, 3, (ClassContextSpecific << 6) | tag, 1, 1}},
		{true, []byte{0x30, 3, (ClassContextSpecific << 6) | tag | isCompound, 1, 1}},
		{false, []byte{0x30, 3, (ClassApplication << 6) | tag | isCompound, 1, 1}},
		{false, []byte{0x30, 3, (ClassPrivate << 6) | tag | isCompound, 1, 1}},
	}

	for i, test := range tests {
		var tagged taggedRawValue
		if _, err := Unmarshal(test.derBytes, &tagged); (err == nil) != test.shouldMatch {
			t.Errorf("#%d: unexpected result parsing %x: %s", i, test.derBytes, err)
		}

		// An untagged RawValue should accept anything.
		var untagged untaggedRawValue
		if _, err := Unmarshal(test.derBytes, &untagged); err != nil {
			t.Errorf("#%d: unexpected failure parsing %x with untagged RawValue: %s", i, test.derBytes, err)
		}
	}
}

var bmpStringTests = []struct {
	decoded    string
	encodedHex string
}{
	{"", "0000"},
	// Example from https://tools.ietf.org/html/rfc7292#appendix-B.
	{"Beavis", "0042006500610076006900730000"},
	// Some characters from the "Letterlike Symbols Unicode block".
	{"\u2115 - Double-struck N", "21150020002d00200044006f00750062006c0065002d00730074007200750063006b0020004e0000"},
}

func TestBMPString(t *testing.T) {
	for i, test := range bmpStringTests {
		encoded, err := hex.DecodeString(test.encodedHex)
		if err != nil {
			t.Fatalf("#%d: failed to decode from hex string", i)
		}

		decoded, err := parseBMPString(encoded)

		if err != nil {
			t.Errorf("#%d: decoding output gave an error: %s", i, err)
			continue
		}

		if decoded != test.decoded {
			t.Errorf("#%d: decoding output resulted in %q, but it should have been %q", i, decoded, test.decoded)
			continue
		}
	}
}

func TestNonMinimalEncodedOID(t *testing.T) {
	h, err := hex.DecodeString("060a2a80864886f70d01010b")
	if err != nil {
		t.Fatalf("failed to decode from hex string: %s", err)
	}
	var oid ObjectIdentifier
	_, err = Unmarshal(h, &oid)
	if err == nil {
		t.Fatalf("accepted non-minimally encoded oid")
	}
}
