1// Copyright 2009 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package base64
6
7import (
8	"bytes"
9	"errors"
10	"fmt"
11	"io"
12	"io/ioutil"
13	"reflect"
14	"strings"
15	"testing"
16	"time"
17)
18
19type testpair struct {
20	decoded, encoded string
21}
22
23var pairs = []testpair{
24	// RFC 3548 examples
25	{"\x14\xfb\x9c\x03\xd9\x7e", "FPucA9l+"},
26	{"\x14\xfb\x9c\x03\xd9", "FPucA9k="},
27	{"\x14\xfb\x9c\x03", "FPucAw=="},
28
29	// RFC 4648 examples
30	{"", ""},
31	{"f", "Zg=="},
32	{"fo", "Zm8="},
33	{"foo", "Zm9v"},
34	{"foob", "Zm9vYg=="},
35	{"fooba", "Zm9vYmE="},
36	{"foobar", "Zm9vYmFy"},
37
38	// Wikipedia examples
39	{"sure.", "c3VyZS4="},
40	{"sure", "c3VyZQ=="},
41	{"sur", "c3Vy"},
42	{"su", "c3U="},
43	{"leasure.", "bGVhc3VyZS4="},
44	{"easure.", "ZWFzdXJlLg=="},
45	{"asure.", "YXN1cmUu"},
46	{"sure.", "c3VyZS4="},
47}
48
49// Do nothing to a reference base64 string (leave in standard format)
50func stdRef(ref string) string {
51	return ref
52}
53
54// Convert a reference string to URL-encoding
55func urlRef(ref string) string {
56	ref = strings.ReplaceAll(ref, "+", "-")
57	ref = strings.ReplaceAll(ref, "/", "_")
58	return ref
59}
60
61// Convert a reference string to raw, unpadded format
62func rawRef(ref string) string {
63	return strings.TrimRight(ref, "=")
64}
65
66// Both URL and unpadding conversions
67func rawURLRef(ref string) string {
68	return rawRef(urlRef(ref))
69}
70
71// A nonstandard encoding with a funny padding character, for testing
72var funnyEncoding = NewEncoding(encodeStd).WithPadding(rune('@'))
73
74func funnyRef(ref string) string {
75	return strings.ReplaceAll(ref, "=", "@")
76}
77
78type encodingTest struct {
79	enc  *Encoding           // Encoding to test
80	conv func(string) string // Reference string converter
81}
82
83var encodingTests = []encodingTest{
84	{StdEncoding, stdRef},
85	{URLEncoding, urlRef},
86	{RawStdEncoding, rawRef},
87	{RawURLEncoding, rawURLRef},
88	{funnyEncoding, funnyRef},
89	{StdEncoding.Strict(), stdRef},
90	{URLEncoding.Strict(), urlRef},
91	{RawStdEncoding.Strict(), rawRef},
92	{RawURLEncoding.Strict(), rawURLRef},
93	{funnyEncoding.Strict(), funnyRef},
94}
95
96var bigtest = testpair{
97	"Twas brillig, and the slithy toves",
98	"VHdhcyBicmlsbGlnLCBhbmQgdGhlIHNsaXRoeSB0b3Zlcw==",
99}
100
101func testEqual(t *testing.T, msg string, args ...interface{}) bool {
102	t.Helper()
103	if args[len(args)-2] != args[len(args)-1] {
104		t.Errorf(msg, args...)
105		return false
106	}
107	return true
108}
109
110func TestEncode(t *testing.T) {
111	for _, p := range pairs {
112		for _, tt := range encodingTests {
113			got := tt.enc.EncodeToString([]byte(p.decoded))
114			testEqual(t, "Encode(%q) = %q, want %q", p.decoded,
115				got, tt.conv(p.encoded))
116		}
117	}
118}
119
120func TestEncoder(t *testing.T) {
121	for _, p := range pairs {
122		bb := &bytes.Buffer{}
123		encoder := NewEncoder(StdEncoding, bb)
124		encoder.Write([]byte(p.decoded))
125		encoder.Close()
126		testEqual(t, "Encode(%q) = %q, want %q", p.decoded, bb.String(), p.encoded)
127	}
128}
129
130func TestEncoderBuffering(t *testing.T) {
131	input := []byte(bigtest.decoded)
132	for bs := 1; bs <= 12; bs++ {
133		bb := &bytes.Buffer{}
134		encoder := NewEncoder(StdEncoding, bb)
135		for pos := 0; pos < len(input); pos += bs {
136			end := pos + bs
137			if end > len(input) {
138				end = len(input)
139			}
140			n, err := encoder.Write(input[pos:end])
141			testEqual(t, "Write(%q) gave error %v, want %v", input[pos:end], err, error(nil))
142			testEqual(t, "Write(%q) gave length %v, want %v", input[pos:end], n, end-pos)
143		}
144		err := encoder.Close()
145		testEqual(t, "Close gave error %v, want %v", err, error(nil))
146		testEqual(t, "Encoding/%d of %q = %q, want %q", bs, bigtest.decoded, bb.String(), bigtest.encoded)
147	}
148}
149
150func TestDecode(t *testing.T) {
151	for _, p := range pairs {
152		for _, tt := range encodingTests {
153			encoded := tt.conv(p.encoded)
154			dbuf := make([]byte, tt.enc.DecodedLen(len(encoded)))
155			count, err := tt.enc.Decode(dbuf, []byte(encoded))
156			testEqual(t, "Decode(%q) = error %v, want %v", encoded, err, error(nil))
157			testEqual(t, "Decode(%q) = length %v, want %v", encoded, count, len(p.decoded))
158			testEqual(t, "Decode(%q) = %q, want %q", encoded, string(dbuf[0:count]), p.decoded)
159
160			dbuf, err = tt.enc.DecodeString(encoded)
161			testEqual(t, "DecodeString(%q) = error %v, want %v", encoded, err, error(nil))
162			testEqual(t, "DecodeString(%q) = %q, want %q", encoded, string(dbuf), p.decoded)
163		}
164	}
165}
166
167func TestDecoder(t *testing.T) {
168	for _, p := range pairs {
169		decoder := NewDecoder(StdEncoding, strings.NewReader(p.encoded))
170		dbuf := make([]byte, StdEncoding.DecodedLen(len(p.encoded)))
171		count, err := decoder.Read(dbuf)
172		if err != nil && err != io.EOF {
173			t.Fatal("Read failed", err)
174		}
175		testEqual(t, "Read from %q = length %v, want %v", p.encoded, count, len(p.decoded))
176		testEqual(t, "Decoding of %q = %q, want %q", p.encoded, string(dbuf[0:count]), p.decoded)
177		if err != io.EOF {
178			count, err = decoder.Read(dbuf)
179		}
180		testEqual(t, "Read from %q = %v, want %v", p.encoded, err, io.EOF)
181	}
182}
183
184func TestDecoderBuffering(t *testing.T) {
185	for bs := 1; bs <= 12; bs++ {
186		decoder := NewDecoder(StdEncoding, strings.NewReader(bigtest.encoded))
187		buf := make([]byte, len(bigtest.decoded)+12)
188		var total int
189		var n int
190		var err error
191		for total = 0; total < len(bigtest.decoded) && err == nil; {
192			n, err = decoder.Read(buf[total : total+bs])
193			total += n
194		}
195		if err != nil && err != io.EOF {
196			t.Errorf("Read from %q at pos %d = %d, unexpected error %v", bigtest.encoded, total, n, err)
197		}
198		testEqual(t, "Decoding/%d of %q = %q, want %q", bs, bigtest.encoded, string(buf[0:total]), bigtest.decoded)
199	}
200}
201
202func TestDecodeCorrupt(t *testing.T) {
203	testCases := []struct {
204		input  string
205		offset int // -1 means no corruption.
206	}{
207		{"", -1},
208		{"\n", -1},
209		{"AAA=\n", -1},
210		{"AAAA\n", -1},
211		{"!!!!", 0},
212		{"====", 0},
213		{"x===", 1},
214		{"=AAA", 0},
215		{"A=AA", 1},
216		{"AA=A", 2},
217		{"AA==A", 4},
218		{"AAA=AAAA", 4},
219		{"AAAAA", 4},
220		{"AAAAAA", 4},
221		{"A=", 1},
222		{"A==", 1},
223		{"AA=", 3},
224		{"AA==", -1},
225		{"AAA=", -1},
226		{"AAAA", -1},
227		{"AAAAAA=", 7},
228		{"YWJjZA=====", 8},
229		{"A!\n", 1},
230		{"A=\n", 1},
231	}
232	for _, tc := range testCases {
233		dbuf := make([]byte, StdEncoding.DecodedLen(len(tc.input)))
234		_, err := StdEncoding.Decode(dbuf, []byte(tc.input))
235		if tc.offset == -1 {
236			if err != nil {
237				t.Error("Decoder wrongly detected corruption in", tc.input)
238			}
239			continue
240		}
241		switch err := err.(type) {
242		case CorruptInputError:
243			testEqual(t, "Corruption in %q at offset %v, want %v", tc.input, int(err), tc.offset)
244		default:
245			t.Error("Decoder failed to detect corruption in", tc)
246		}
247	}
248}
249
250func TestEncodedLen(t *testing.T) {
251	for _, tt := range []struct {
252		enc  *Encoding
253		n    int
254		want int
255	}{
256		{RawStdEncoding, 0, 0},
257		{RawStdEncoding, 1, 2},
258		{RawStdEncoding, 2, 3},
259		{RawStdEncoding, 3, 4},
260		{RawStdEncoding, 7, 10},
261		{StdEncoding, 0, 0},
262		{StdEncoding, 1, 4},
263		{StdEncoding, 2, 4},
264		{StdEncoding, 3, 4},
265		{StdEncoding, 4, 8},
266		{StdEncoding, 7, 12},
267	} {
268		if got := tt.enc.EncodedLen(tt.n); got != tt.want {
269			t.Errorf("EncodedLen(%d): got %d, want %d", tt.n, got, tt.want)
270		}
271	}
272}
273
274func TestDecodedLen(t *testing.T) {
275	for _, tt := range []struct {
276		enc  *Encoding
277		n    int
278		want int
279	}{
280		{RawStdEncoding, 0, 0},
281		{RawStdEncoding, 2, 1},
282		{RawStdEncoding, 3, 2},
283		{RawStdEncoding, 4, 3},
284		{RawStdEncoding, 10, 7},
285		{StdEncoding, 0, 0},
286		{StdEncoding, 4, 3},
287		{StdEncoding, 8, 6},
288	} {
289		if got := tt.enc.DecodedLen(tt.n); got != tt.want {
290			t.Errorf("DecodedLen(%d): got %d, want %d", tt.n, got, tt.want)
291		}
292	}
293}
294
295func TestBig(t *testing.T) {
296	n := 3*1000 + 1
297	raw := make([]byte, n)
298	const alpha = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
299	for i := 0; i < n; i++ {
300		raw[i] = alpha[i%len(alpha)]
301	}
302	encoded := new(bytes.Buffer)
303	w := NewEncoder(StdEncoding, encoded)
304	nn, err := w.Write(raw)
305	if nn != n || err != nil {
306		t.Fatalf("Encoder.Write(raw) = %d, %v want %d, nil", nn, err, n)
307	}
308	err = w.Close()
309	if err != nil {
310		t.Fatalf("Encoder.Close() = %v want nil", err)
311	}
312	decoded, err := ioutil.ReadAll(NewDecoder(StdEncoding, encoded))
313	if err != nil {
314		t.Fatalf("ioutil.ReadAll(NewDecoder(...)): %v", err)
315	}
316
317	if !bytes.Equal(raw, decoded) {
318		var i int
319		for i = 0; i < len(decoded) && i < len(raw); i++ {
320			if decoded[i] != raw[i] {
321				break
322			}
323		}
324		t.Errorf("Decode(Encode(%d-byte string)) failed at offset %d", n, i)
325	}
326}
327
328func TestNewLineCharacters(t *testing.T) {
329	// Each of these should decode to the string "sure", without errors.
330	const expected = "sure"
331	examples := []string{
332		"c3VyZQ==",
333		"c3VyZQ==\r",
334		"c3VyZQ==\n",
335		"c3VyZQ==\r\n",
336		"c3VyZ\r\nQ==",
337		"c3V\ryZ\nQ==",
338		"c3V\nyZ\rQ==",
339		"c3VyZ\nQ==",
340		"c3VyZQ\n==",
341		"c3VyZQ=\n=",
342		"c3VyZQ=\r\n\r\n=",
343	}
344	for _, e := range examples {
345		buf, err := StdEncoding.DecodeString(e)
346		if err != nil {
347			t.Errorf("Decode(%q) failed: %v", e, err)
348			continue
349		}
350		if s := string(buf); s != expected {
351			t.Errorf("Decode(%q) = %q, want %q", e, s, expected)
352		}
353	}
354}
355
356type nextRead struct {
357	n   int   // bytes to return
358	err error // error to return
359}
360
361// faultInjectReader returns data from source, rate-limited
362// and with the errors as written to nextc.
363type faultInjectReader struct {
364	source string
365	nextc  <-chan nextRead
366}
367
368func (r *faultInjectReader) Read(p []byte) (int, error) {
369	nr := <-r.nextc
370	if len(p) > nr.n {
371		p = p[:nr.n]
372	}
373	n := copy(p, r.source)
374	r.source = r.source[n:]
375	return n, nr.err
376}
377
378// tests that we don't ignore errors from our underlying reader
379func TestDecoderIssue3577(t *testing.T) {
380	next := make(chan nextRead, 10)
381	wantErr := errors.New("my error")
382	next <- nextRead{5, nil}
383	next <- nextRead{10, wantErr}
384	next <- nextRead{0, wantErr}
385	d := NewDecoder(StdEncoding, &faultInjectReader{
386		source: "VHdhcyBicmlsbGlnLCBhbmQgdGhlIHNsaXRoeSB0b3Zlcw==", // twas brillig...
387		nextc:  next,
388	})
389	errc := make(chan error)
390	go func() {
391		_, err := ioutil.ReadAll(d)
392		errc <- err
393	}()
394	select {
395	case err := <-errc:
396		if err != wantErr {
397			t.Errorf("got error %v; want %v", err, wantErr)
398		}
399	case <-time.After(5 * time.Second):
400		t.Errorf("timeout; Decoder blocked without returning an error")
401	}
402}
403
404func TestDecoderIssue4779(t *testing.T) {
405	encoded := `CP/EAT8AAAEF
406AQEBAQEBAAAAAAAAAAMAAQIEBQYHCAkKCwEAAQUBAQEBAQEAAAAAAAAAAQACAwQFBgcICQoLEAAB
407BAEDAgQCBQcGCAUDDDMBAAIRAwQhEjEFQVFhEyJxgTIGFJGhsUIjJBVSwWIzNHKC0UMHJZJT8OHx
408Y3M1FqKygyZEk1RkRcKjdDYX0lXiZfKzhMPTdePzRieUpIW0lcTU5PSltcXV5fVWZnaGlqa2xtbm
4099jdHV2d3h5ent8fX5/cRAAICAQIEBAMEBQYHBwYFNQEAAhEDITESBEFRYXEiEwUygZEUobFCI8FS
4100fAzJGLhcoKSQ1MVY3M08SUGFqKygwcmNcLSRJNUoxdkRVU2dGXi8rOEw9N14/NGlKSFtJXE1OT0
411pbXF1eX1VmZ2hpamtsbW5vYnN0dXZ3eHl6e3x//aAAwDAQACEQMRAD8A9VSSSSUpJJJJSkkkJ+Tj
4121kiy1jCJJDnAcCTykpKkuQ6p/jN6FgmxlNduXawwAzaGH+V6jn/R/wCt71zdn+N/qL3kVYFNYB4N
413ji6PDVjWpKp9TSXnvTf8bFNjg3qOEa2n6VlLpj/rT/pf567DpX1i6L1hs9Py67X8mqdtg/rUWbbf
414+gkp0kkkklKSSSSUpJJJJT//0PVUkkklKVLq3WMDpGI7KzrNjADtYNXvI/Mqr/Pd/q9W3vaxjnvM
415NaCXE9gNSvGPrf8AWS3qmba5jjsJhoB0DAf0NDf6sevf+/lf8Hj0JJATfWT6/dV6oXU1uOLQeKKn
416EQP+Hubtfe/+R7Mf/g7f5xcocp++Z11JMCJPgFBxOg7/AOuqDx8I/ikpkXkmSdU8mJIJA/O8EMAy
417j+mSARB/17pKVXYWHXjsj7yIex0PadzXMO1zT5KHoNA3HT8ietoGhgjsfA+CSnvvqh/jJtqsrwOv
4182b6NGNzXfTYexzJ+nU7/ALkf4P8Awv6P9KvTQQ4AgyDqCF85Pho3CTB7eHwXoH+LT65uZbX9X+o2
419bqbPb06551Y4
420`
421	encodedShort := strings.ReplaceAll(encoded, "\n", "")
422
423	dec := NewDecoder(StdEncoding, strings.NewReader(encoded))
424	res1, err := ioutil.ReadAll(dec)
425	if err != nil {
426		t.Errorf("ReadAll failed: %v", err)
427	}
428
429	dec = NewDecoder(StdEncoding, strings.NewReader(encodedShort))
430	var res2 []byte
431	res2, err = ioutil.ReadAll(dec)
432	if err != nil {
433		t.Errorf("ReadAll failed: %v", err)
434	}
435
436	if !bytes.Equal(res1, res2) {
437		t.Error("Decoded results not equal")
438	}
439}
440
441func TestDecoderIssue7733(t *testing.T) {
442	s, err := StdEncoding.DecodeString("YWJjZA=====")
443	want := CorruptInputError(8)
444	if !reflect.DeepEqual(want, err) {
445		t.Errorf("Error = %v; want CorruptInputError(8)", err)
446	}
447	if string(s) != "abcd" {
448		t.Errorf("DecodeString = %q; want abcd", s)
449	}
450}
451
452func TestDecoderIssue15656(t *testing.T) {
453	_, err := StdEncoding.Strict().DecodeString("WvLTlMrX9NpYDQlEIFlnDB==")
454	want := CorruptInputError(22)
455	if !reflect.DeepEqual(want, err) {
456		t.Errorf("Error = %v; want CorruptInputError(22)", err)
457	}
458	_, err = StdEncoding.Strict().DecodeString("WvLTlMrX9NpYDQlEIFlnDA==")
459	if err != nil {
460		t.Errorf("Error = %v; want nil", err)
461	}
462	_, err = StdEncoding.DecodeString("WvLTlMrX9NpYDQlEIFlnDB==")
463	if err != nil {
464		t.Errorf("Error = %v; want nil", err)
465	}
466}
467
468func BenchmarkEncodeToString(b *testing.B) {
469	data := make([]byte, 8192)
470	b.SetBytes(int64(len(data)))
471	for i := 0; i < b.N; i++ {
472		StdEncoding.EncodeToString(data)
473	}
474}
475
476func BenchmarkDecodeString(b *testing.B) {
477	sizes := []int{2, 4, 8, 64, 8192}
478	benchFunc := func(b *testing.B, benchSize int) {
479		data := StdEncoding.EncodeToString(make([]byte, benchSize))
480		b.SetBytes(int64(len(data)))
481		b.ResetTimer()
482		for i := 0; i < b.N; i++ {
483			StdEncoding.DecodeString(data)
484		}
485	}
486	for _, size := range sizes {
487		b.Run(fmt.Sprintf("%d", size), func(b *testing.B) {
488			benchFunc(b, size)
489		})
490	}
491}
492
493func TestDecoderRaw(t *testing.T) {
494	source := "AAAAAA"
495	want := []byte{0, 0, 0, 0}
496
497	// Direct.
498	dec1, err := RawURLEncoding.DecodeString(source)
499	if err != nil || !bytes.Equal(dec1, want) {
500		t.Errorf("RawURLEncoding.DecodeString(%q) = %x, %v, want %x, nil", source, dec1, err, want)
501	}
502
503	// Through reader. Used to fail.
504	r := NewDecoder(RawURLEncoding, bytes.NewReader([]byte(source)))
505	dec2, err := ioutil.ReadAll(io.LimitReader(r, 100))
506	if err != nil || !bytes.Equal(dec2, want) {
507		t.Errorf("reading NewDecoder(RawURLEncoding, %q) = %x, %v, want %x, nil", source, dec2, err, want)
508	}
509
510	// Should work with padding.
511	r = NewDecoder(URLEncoding, bytes.NewReader([]byte(source+"==")))
512	dec3, err := ioutil.ReadAll(r)
513	if err != nil || !bytes.Equal(dec3, want) {
514		t.Errorf("reading NewDecoder(URLEncoding, %q) = %x, %v, want %x, nil", source+"==", dec3, err, want)
515	}
516}
517