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 ascii85
6
7import (
8	"bytes"
9	"io"
10	"strings"
11	"testing"
12)
13
14type testpair struct {
15	decoded, encoded string
16}
17
18var bigtest = testpair{
19	"Man is distinguished, not only by his reason, but by this singular passion from " +
20		"other animals, which is a lust of the mind, that by a perseverance of delight in " +
21		"the continued and indefatigable generation of knowledge, exceeds the short " +
22		"vehemence of any carnal pleasure.",
23	"9jqo^BlbD-BleB1DJ+*+F(f,q/0JhKF<GL>[email protected]$d7F!,L7@<6@)/0JDEF<G%<+EV:2F!,\n" +
24		"O<DJ+*.@<*K0@<6L(Df-\\0Ec5e;DffZ(EZee.Bl.9pF\"AGXBPCsi+DGm>@3BB/F*&OCAfu2/AKY\n" +
25		"i(DIb:@FD,*)+C]U=@3BN#EcYf8ATD3s@q?d$AftVqCh[NqF<G:8+EV:.+Cf>-FD5W8ARlolDIa\n" +
26		"l(DId<j@<?3r@:F%a+D58'ATD4$Bl@l3De:,-DJs`8ARoFb/0JMK@qB4^F!,R<AKZ&-DfTqBG%G\n" +
27		">uD.RTpAKYo'+CT/5+Cei#DII?(E,9)oF*2M7/c\n",
28}
29
30var pairs = []testpair{
31	// Encode returns 0 when len(src) is 0
32	{
33		"",
34		"",
35	},
36	// Wikipedia example
37	bigtest,
38	// Special case when shortening !!!!! to z.
39	{
40		"\000\000\000\000",
41		"z",
42	},
43}
44
45func testEqual(t *testing.T, msg string, args ...any) bool {
46	t.Helper()
47	if args[len(args)-2] != args[len(args)-1] {
48		t.Errorf(msg, args...)
49		return false
50	}
51	return true
52}
53
54func strip85(s string) string {
55	t := make([]byte, len(s))
56	w := 0
57	for r := 0; r < len(s); r++ {
58		c := s[r]
59		if c > ' ' {
60			t[w] = c
61			w++
62		}
63	}
64	return string(t[0:w])
65}
66
67func TestEncode(t *testing.T) {
68	for _, p := range pairs {
69		buf := make([]byte, MaxEncodedLen(len(p.decoded)))
70		n := Encode(buf, []byte(p.decoded))
71		buf = buf[0:n]
72		testEqual(t, "Encode(%q) = %q, want %q", p.decoded, strip85(string(buf)), strip85(p.encoded))
73	}
74}
75
76func TestEncoder(t *testing.T) {
77	for _, p := range pairs {
78		bb := &strings.Builder{}
79		encoder := NewEncoder(bb)
80		encoder.Write([]byte(p.decoded))
81		encoder.Close()
82		testEqual(t, "Encode(%q) = %q, want %q", p.decoded, strip85(bb.String()), strip85(p.encoded))
83	}
84}
85
86func TestEncoderBuffering(t *testing.T) {
87	input := []byte(bigtest.decoded)
88	for bs := 1; bs <= 12; bs++ {
89		bb := &strings.Builder{}
90		encoder := NewEncoder(bb)
91		for pos := 0; pos < len(input); pos += bs {
92			end := pos + bs
93			if end > len(input) {
94				end = len(input)
95			}
96			n, err := encoder.Write(input[pos:end])
97			testEqual(t, "Write(%q) gave error %v, want %v", input[pos:end], err, error(nil))
98			testEqual(t, "Write(%q) gave length %v, want %v", input[pos:end], n, end-pos)
99		}
100		err := encoder.Close()
101		testEqual(t, "Close gave error %v, want %v", err, error(nil))
102		testEqual(t, "Encoding/%d of %q = %q, want %q", bs, bigtest.decoded, strip85(bb.String()), strip85(bigtest.encoded))
103	}
104}
105
106func TestDecode(t *testing.T) {
107	for _, p := range pairs {
108		dbuf := make([]byte, 4*len(p.encoded))
109		ndst, nsrc, err := Decode(dbuf, []byte(p.encoded), true)
110		testEqual(t, "Decode(%q) = error %v, want %v", p.encoded, err, error(nil))
111		testEqual(t, "Decode(%q) = nsrc %v, want %v", p.encoded, nsrc, len(p.encoded))
112		testEqual(t, "Decode(%q) = ndst %v, want %v", p.encoded, ndst, len(p.decoded))
113		testEqual(t, "Decode(%q) = %q, want %q", p.encoded, string(dbuf[0:ndst]), p.decoded)
114	}
115}
116
117func TestDecoder(t *testing.T) {
118	for _, p := range pairs {
119		decoder := NewDecoder(strings.NewReader(p.encoded))
120		dbuf, err := io.ReadAll(decoder)
121		if err != nil {
122			t.Fatal("Read failed", err)
123		}
124		testEqual(t, "Read from %q = length %v, want %v", p.encoded, len(dbuf), len(p.decoded))
125		testEqual(t, "Decoding of %q = %q, want %q", p.encoded, string(dbuf), p.decoded)
126		if err != nil {
127			testEqual(t, "Read from %q = %v, want %v", p.encoded, err, io.EOF)
128		}
129	}
130}
131
132func TestDecoderBuffering(t *testing.T) {
133	for bs := 1; bs <= 12; bs++ {
134		decoder := NewDecoder(strings.NewReader(bigtest.encoded))
135		buf := make([]byte, len(bigtest.decoded)+12)
136		var total int
137		var n int
138		var err error
139		for total = 0; total < len(bigtest.decoded) && err == nil; {
140			n, err = decoder.Read(buf[total : total+bs])
141			total += n
142		}
143		if err != nil && err != io.EOF {
144			t.Errorf("Read from %q at pos %d = %d, unexpected error %v", bigtest.encoded, total, n, err)
145		}
146		testEqual(t, "Decoding/%d of %q = %q, want %q", bs, bigtest.encoded, string(buf[0:total]), bigtest.decoded)
147	}
148}
149
150func TestDecodeCorrupt(t *testing.T) {
151	type corrupt struct {
152		e string
153		p int
154	}
155	examples := []corrupt{
156		{"v", 0},
157		{"!z!!!!!!!!!", 1},
158	}
159
160	for _, e := range examples {
161		dbuf := make([]byte, 4*len(e.e))
162		_, _, err := Decode(dbuf, []byte(e.e), true)
163		switch err := err.(type) {
164		case CorruptInputError:
165			testEqual(t, "Corruption in %q at offset %v, want %v", e.e, int(err), e.p)
166		default:
167			t.Error("Decoder failed to detect corruption in", e)
168		}
169	}
170}
171
172func TestBig(t *testing.T) {
173	n := 3*1000 + 1
174	raw := make([]byte, n)
175	const alpha = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
176	for i := 0; i < n; i++ {
177		raw[i] = alpha[i%len(alpha)]
178	}
179	encoded := new(bytes.Buffer)
180	w := NewEncoder(encoded)
181	nn, err := w.Write(raw)
182	if nn != n || err != nil {
183		t.Fatalf("Encoder.Write(raw) = %d, %v want %d, nil", nn, err, n)
184	}
185	err = w.Close()
186	if err != nil {
187		t.Fatalf("Encoder.Close() = %v want nil", err)
188	}
189	decoded, err := io.ReadAll(NewDecoder(encoded))
190	if err != nil {
191		t.Fatalf("io.ReadAll(NewDecoder(...)): %v", err)
192	}
193
194	if !bytes.Equal(raw, decoded) {
195		var i int
196		for i = 0; i < len(decoded) && i < len(raw); i++ {
197			if decoded[i] != raw[i] {
198				break
199			}
200		}
201		t.Errorf("Decode(Encode(%d-byte string)) failed at offset %d", n, i)
202	}
203}
204
205func TestDecoderInternalWhitespace(t *testing.T) {
206	s := strings.Repeat(" ", 2048) + "z"
207	decoded, err := io.ReadAll(NewDecoder(strings.NewReader(s)))
208	if err != nil {
209		t.Errorf("Decode gave error %v", err)
210	}
211	if want := []byte("\000\000\000\000"); !bytes.Equal(want, decoded) {
212		t.Errorf("Decode failed: got %v, want %v", decoded, want)
213	}
214}
215