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 bytes_test
6
7import (
8	. "bytes"
9	"fmt"
10	"internal/testenv"
11	"math/rand"
12	"reflect"
13	"strings"
14	"testing"
15	"unicode"
16	"unicode/utf8"
17)
18
19func eq(a, b []string) bool {
20	if len(a) != len(b) {
21		return false
22	}
23	for i := 0; i < len(a); i++ {
24		if a[i] != b[i] {
25			return false
26		}
27	}
28	return true
29}
30
31func sliceOfString(s [][]byte) []string {
32	result := make([]string, len(s))
33	for i, v := range s {
34		result[i] = string(v)
35	}
36	return result
37}
38
39// For ease of reading, the test cases use strings that are converted to byte
40// slices before invoking the functions.
41
42var abcd = "abcd"
43var faces = "☺☻☹"
44var commas = "1,2,3,4"
45var dots = "1....2....3....4"
46
47type BinOpTest struct {
48	a string
49	b string
50	i int
51}
52
53func TestEqual(t *testing.T) {
54	for _, tt := range compareTests {
55		eql := Equal(tt.a, tt.b)
56		if eql != (tt.i == 0) {
57			t.Errorf(`Equal(%q, %q) = %v`, tt.a, tt.b, eql)
58		}
59		eql = EqualPortable(tt.a, tt.b)
60		if eql != (tt.i == 0) {
61			t.Errorf(`EqualPortable(%q, %q) = %v`, tt.a, tt.b, eql)
62		}
63	}
64}
65
66func TestEqualExhaustive(t *testing.T) {
67	var size = 128
68	if testing.Short() {
69		size = 32
70	}
71	a := make([]byte, size)
72	b := make([]byte, size)
73	b_init := make([]byte, size)
74	// randomish but deterministic data
75	for i := 0; i < size; i++ {
76		a[i] = byte(17 * i)
77		b_init[i] = byte(23*i + 100)
78	}
79
80	for len := 0; len <= size; len++ {
81		for x := 0; x <= size-len; x++ {
82			for y := 0; y <= size-len; y++ {
83				copy(b, b_init)
84				copy(b[y:y+len], a[x:x+len])
85				if !Equal(a[x:x+len], b[y:y+len]) || !Equal(b[y:y+len], a[x:x+len]) {
86					t.Errorf("Equal(%d, %d, %d) = false", len, x, y)
87				}
88			}
89		}
90	}
91}
92
93// make sure Equal returns false for minimally different strings. The data
94// is all zeros except for a single one in one location.
95func TestNotEqual(t *testing.T) {
96	var size = 128
97	if testing.Short() {
98		size = 32
99	}
100	a := make([]byte, size)
101	b := make([]byte, size)
102
103	for len := 0; len <= size; len++ {
104		for x := 0; x <= size-len; x++ {
105			for y := 0; y <= size-len; y++ {
106				for diffpos := x; diffpos < x+len; diffpos++ {
107					a[diffpos] = 1
108					if Equal(a[x:x+len], b[y:y+len]) || Equal(b[y:y+len], a[x:x+len]) {
109						t.Errorf("NotEqual(%d, %d, %d, %d) = true", len, x, y, diffpos)
110					}
111					a[diffpos] = 0
112				}
113			}
114		}
115	}
116}
117
118var indexTests = []BinOpTest{
119	{"", "", 0},
120	{"", "a", -1},
121	{"", "foo", -1},
122	{"fo", "foo", -1},
123	{"foo", "baz", -1},
124	{"foo", "foo", 0},
125	{"oofofoofooo", "f", 2},
126	{"oofofoofooo", "foo", 4},
127	{"barfoobarfoo", "foo", 3},
128	{"foo", "", 0},
129	{"foo", "o", 1},
130	{"abcABCabc", "A", 3},
131	// cases with one byte strings - test IndexByte and special case in Index()
132	{"", "a", -1},
133	{"x", "a", -1},
134	{"x", "x", 0},
135	{"abc", "a", 0},
136	{"abc", "b", 1},
137	{"abc", "c", 2},
138	{"abc", "x", -1},
139	{"barfoobarfooyyyzzzyyyzzzyyyzzzyyyxxxzzzyyy", "x", 33},
140	{"foofyfoobarfoobar", "y", 4},
141	{"oooooooooooooooooooooo", "r", -1},
142	// test fallback to Rabin-Karp.
143	{"oxoxoxoxoxoxoxoxoxoxoxoy", "oy", 22},
144	{"oxoxoxoxoxoxoxoxoxoxoxox", "oy", -1},
145}
146
147var lastIndexTests = []BinOpTest{
148	{"", "", 0},
149	{"", "a", -1},
150	{"", "foo", -1},
151	{"fo", "foo", -1},
152	{"foo", "foo", 0},
153	{"foo", "f", 0},
154	{"oofofoofooo", "f", 7},
155	{"oofofoofooo", "foo", 7},
156	{"barfoobarfoo", "foo", 9},
157	{"foo", "", 3},
158	{"foo", "o", 2},
159	{"abcABCabc", "A", 3},
160	{"abcABCabc", "a", 6},
161}
162
163var indexAnyTests = []BinOpTest{
164	{"", "", -1},
165	{"", "a", -1},
166	{"", "abc", -1},
167	{"a", "", -1},
168	{"a", "a", 0},
169	{"aaa", "a", 0},
170	{"abc", "xyz", -1},
171	{"abc", "xcz", 2},
172	{"ab☺c", "x☺yz", 2},
173	{"a☺b☻c☹d", "cx", len("a☺b☻")},
174	{"a☺b☻c☹d", "uvw☻xyz", len("a☺b")},
175	{"aRegExp*", ".(|)*+?^$[]", 7},
176	{dots + dots + dots, " ", -1},
177	{"012abcba210", "\xffb", 4},
178	{"012\x80bcb\x80210", "\xffb", 3},
179}
180
181var lastIndexAnyTests = []BinOpTest{
182	{"", "", -1},
183	{"", "a", -1},
184	{"", "abc", -1},
185	{"a", "", -1},
186	{"a", "a", 0},
187	{"aaa", "a", 2},
188	{"abc", "xyz", -1},
189	{"abc", "ab", 1},
190	{"ab☺c", "x☺yz", 2},
191	{"a☺b☻c☹d", "cx", len("a☺b☻")},
192	{"a☺b☻c☹d", "uvw☻xyz", len("a☺b")},
193	{"a.RegExp*", ".(|)*+?^$[]", 8},
194	{dots + dots + dots, " ", -1},
195	{"012abcba210", "\xffb", 6},
196	{"012\x80bcb\x80210", "\xffb", 7},
197}
198
199// Execute f on each test case.  funcName should be the name of f; it's used
200// in failure reports.
201func runIndexTests(t *testing.T, f func(s, sep []byte) int, funcName string, testCases []BinOpTest) {
202	for _, test := range testCases {
203		a := []byte(test.a)
204		b := []byte(test.b)
205		actual := f(a, b)
206		if actual != test.i {
207			t.Errorf("%s(%q,%q) = %v; want %v", funcName, a, b, actual, test.i)
208		}
209	}
210}
211
212func runIndexAnyTests(t *testing.T, f func(s []byte, chars string) int, funcName string, testCases []BinOpTest) {
213	for _, test := range testCases {
214		a := []byte(test.a)
215		actual := f(a, test.b)
216		if actual != test.i {
217			t.Errorf("%s(%q,%q) = %v; want %v", funcName, a, test.b, actual, test.i)
218		}
219	}
220}
221
222func TestIndex(t *testing.T)     { runIndexTests(t, Index, "Index", indexTests) }
223func TestLastIndex(t *testing.T) { runIndexTests(t, LastIndex, "LastIndex", lastIndexTests) }
224func TestIndexAny(t *testing.T)  { runIndexAnyTests(t, IndexAny, "IndexAny", indexAnyTests) }
225func TestLastIndexAny(t *testing.T) {
226	runIndexAnyTests(t, LastIndexAny, "LastIndexAny", lastIndexAnyTests)
227}
228
229func TestIndexByte(t *testing.T) {
230	for _, tt := range indexTests {
231		if len(tt.b) != 1 {
232			continue
233		}
234		a := []byte(tt.a)
235		b := tt.b[0]
236		pos := IndexByte(a, b)
237		if pos != tt.i {
238			t.Errorf(`IndexByte(%q, '%c') = %v`, tt.a, b, pos)
239		}
240		posp := IndexBytePortable(a, b)
241		if posp != tt.i {
242			t.Errorf(`indexBytePortable(%q, '%c') = %v`, tt.a, b, posp)
243		}
244	}
245}
246
247func TestLastIndexByte(t *testing.T) {
248	testCases := []BinOpTest{
249		{"", "q", -1},
250		{"abcdef", "q", -1},
251		{"abcdefabcdef", "a", len("abcdef")},      // something in the middle
252		{"abcdefabcdef", "f", len("abcdefabcde")}, // last byte
253		{"zabcdefabcdef", "z", 0},                 // first byte
254		{"a☺b☻c☹d", "b", len("a☺")},               // non-ascii
255	}
256	for _, test := range testCases {
257		actual := LastIndexByte([]byte(test.a), test.b[0])
258		if actual != test.i {
259			t.Errorf("LastIndexByte(%q,%c) = %v; want %v", test.a, test.b[0], actual, test.i)
260		}
261	}
262}
263
264// test a larger buffer with different sizes and alignments
265func TestIndexByteBig(t *testing.T) {
266	var n = 1024
267	if testing.Short() {
268		n = 128
269	}
270	b := make([]byte, n)
271	for i := 0; i < n; i++ {
272		// different start alignments
273		b1 := b[i:]
274		for j := 0; j < len(b1); j++ {
275			b1[j] = 'x'
276			pos := IndexByte(b1, 'x')
277			if pos != j {
278				t.Errorf("IndexByte(%q, 'x') = %v", b1, pos)
279			}
280			b1[j] = 0
281			pos = IndexByte(b1, 'x')
282			if pos != -1 {
283				t.Errorf("IndexByte(%q, 'x') = %v", b1, pos)
284			}
285		}
286		// different end alignments
287		b1 = b[:i]
288		for j := 0; j < len(b1); j++ {
289			b1[j] = 'x'
290			pos := IndexByte(b1, 'x')
291			if pos != j {
292				t.Errorf("IndexByte(%q, 'x') = %v", b1, pos)
293			}
294			b1[j] = 0
295			pos = IndexByte(b1, 'x')
296			if pos != -1 {
297				t.Errorf("IndexByte(%q, 'x') = %v", b1, pos)
298			}
299		}
300		// different start and end alignments
301		b1 = b[i/2 : n-(i+1)/2]
302		for j := 0; j < len(b1); j++ {
303			b1[j] = 'x'
304			pos := IndexByte(b1, 'x')
305			if pos != j {
306				t.Errorf("IndexByte(%q, 'x') = %v", b1, pos)
307			}
308			b1[j] = 0
309			pos = IndexByte(b1, 'x')
310			if pos != -1 {
311				t.Errorf("IndexByte(%q, 'x') = %v", b1, pos)
312			}
313		}
314	}
315}
316
317// test a small index across all page offsets
318func TestIndexByteSmall(t *testing.T) {
319	b := make([]byte, 5015) // bigger than a page
320	// Make sure we find the correct byte even when straddling a page.
321	for i := 0; i <= len(b)-15; i++ {
322		for j := 0; j < 15; j++ {
323			b[i+j] = byte(100 + j)
324		}
325		for j := 0; j < 15; j++ {
326			p := IndexByte(b[i:i+15], byte(100+j))
327			if p != j {
328				t.Errorf("IndexByte(%q, %d) = %d", b[i:i+15], 100+j, p)
329			}
330		}
331		for j := 0; j < 15; j++ {
332			b[i+j] = 0
333		}
334	}
335	// Make sure matches outside the slice never trigger.
336	for i := 0; i <= len(b)-15; i++ {
337		for j := 0; j < 15; j++ {
338			b[i+j] = 1
339		}
340		for j := 0; j < 15; j++ {
341			p := IndexByte(b[i:i+15], byte(0))
342			if p != -1 {
343				t.Errorf("IndexByte(%q, %d) = %d", b[i:i+15], 0, p)
344			}
345		}
346		for j := 0; j < 15; j++ {
347			b[i+j] = 0
348		}
349	}
350}
351
352func TestIndexRune(t *testing.T) {
353	tests := []struct {
354		in   string
355		rune rune
356		want int
357	}{
358		{"", 'a', -1},
359		{"", '☺', -1},
360		{"foo", '☹', -1},
361		{"foo", 'o', 1},
362		{"foo☺bar", '☺', 3},
363		{"foo☺☻☹bar", '☹', 9},
364		{"a A x", 'A', 2},
365		{"some_text=some_value", '=', 9},
366		{"☺a", 'a', 3},
367		{"a☻☺b", '☺', 4},
368
369		// RuneError should match any invalid UTF-8 byte sequence.
370		{"�", '�', 0},
371		{"\xff", '�', 0},
372		{"☻x�", '�', len("☻x")},
373		{"☻x\xe2\x98", '�', len("☻x")},
374		{"☻x\xe2\x98�", '�', len("☻x")},
375		{"☻x\xe2\x98x", '�', len("☻x")},
376
377		// Invalid rune values should never match.
378		{"a☺b☻c☹d\xe2\x98�\xff�\xed\xa0\x80", -1, -1},
379		{"a☺b☻c☹d\xe2\x98�\xff�\xed\xa0\x80", 0xD800, -1}, // Surrogate pair
380		{"a☺b☻c☹d\xe2\x98�\xff�\xed\xa0\x80", utf8.MaxRune + 1, -1},
381	}
382	for _, tt := range tests {
383		if got := IndexRune([]byte(tt.in), tt.rune); got != tt.want {
384			t.Errorf("IndexRune(%q, %d) = %v; want %v", tt.in, tt.rune, got, tt.want)
385		}
386	}
387
388	haystack := []byte("test世界")
389	allocs := testing.AllocsPerRun(1000, func() {
390		if i := IndexRune(haystack, 's'); i != 2 {
391			t.Fatalf("'s' at %d; want 2", i)
392		}
393		if i := IndexRune(haystack, '世'); i != 4 {
394			t.Fatalf("'世' at %d; want 4", i)
395		}
396	})
397	if allocs != 0 {
398		t.Errorf("expected no allocations, got %f", allocs)
399	}
400}
401
402// test count of a single byte across page offsets
403func TestCountByte(t *testing.T) {
404	b := make([]byte, 5015) // bigger than a page
405	windows := []int{1, 2, 3, 4, 15, 16, 17, 31, 32, 33, 63, 64, 65, 128}
406	testCountWindow := func(i, window int) {
407		for j := 0; j < window; j++ {
408			b[i+j] = byte(100)
409			p := Count(b[i:i+window], []byte{100})
410			if p != j+1 {
411				t.Errorf("TestCountByte.Count(%q, 100) = %d", b[i:i+window], p)
412			}
413			pGeneric := CountGeneric(b[i:i+window], []byte{100})
414			if pGeneric != j+1 {
415				t.Errorf("TestCountByte.CountGeneric(%q, 100) = %d", b[i:i+window], p)
416			}
417		}
418	}
419
420	maxWnd := windows[len(windows)-1]
421
422	for i := 0; i <= 2*maxWnd; i++ {
423		for _, window := range windows {
424			if window > len(b[i:]) {
425				window = len(b[i:])
426			}
427			testCountWindow(i, window)
428			for j := 0; j < window; j++ {
429				b[i+j] = byte(0)
430			}
431		}
432	}
433	for i := 4096 - (maxWnd + 1); i < len(b); i++ {
434		for _, window := range windows {
435			if window > len(b[i:]) {
436				window = len(b[i:])
437			}
438			testCountWindow(i, window)
439			for j := 0; j < window; j++ {
440				b[i+j] = byte(0)
441			}
442		}
443	}
444}
445
446// Make sure we don't count bytes outside our window
447func TestCountByteNoMatch(t *testing.T) {
448	b := make([]byte, 5015)
449	windows := []int{1, 2, 3, 4, 15, 16, 17, 31, 32, 33, 63, 64, 65, 128}
450	for i := 0; i <= len(b); i++ {
451		for _, window := range windows {
452			if window > len(b[i:]) {
453				window = len(b[i:])
454			}
455			// Fill the window with non-match
456			for j := 0; j < window; j++ {
457				b[i+j] = byte(100)
458			}
459			// Try to find something that doesn't exist
460			p := Count(b[i:i+window], []byte{0})
461			if p != 0 {
462				t.Errorf("TestCountByteNoMatch(%q, 0) = %d", b[i:i+window], p)
463			}
464			pGeneric := CountGeneric(b[i:i+window], []byte{0})
465			if pGeneric != 0 {
466				t.Errorf("TestCountByteNoMatch.CountGeneric(%q, 100) = %d", b[i:i+window], p)
467			}
468			for j := 0; j < window; j++ {
469				b[i+j] = byte(0)
470			}
471		}
472	}
473}
474
475var bmbuf []byte
476
477func valName(x int) string {
478	if s := x >> 20; s<<20 == x {
479		return fmt.Sprintf("%dM", s)
480	}
481	if s := x >> 10; s<<10 == x {
482		return fmt.Sprintf("%dK", s)
483	}
484	return fmt.Sprint(x)
485}
486
487func benchBytes(b *testing.B, sizes []int, f func(b *testing.B, n int)) {
488	for _, n := range sizes {
489		if isRaceBuilder && n > 4<<10 {
490			continue
491		}
492		b.Run(valName(n), func(b *testing.B) {
493			if len(bmbuf) < n {
494				bmbuf = make([]byte, n)
495			}
496			b.SetBytes(int64(n))
497			f(b, n)
498		})
499	}
500}
501
502var indexSizes = []int{10, 32, 4 << 10, 4 << 20, 64 << 20}
503
504var isRaceBuilder = strings.HasSuffix(testenv.Builder(), "-race")
505
506func BenchmarkIndexByte(b *testing.B) {
507	benchBytes(b, indexSizes, bmIndexByte(IndexByte))
508}
509
510func BenchmarkIndexBytePortable(b *testing.B) {
511	benchBytes(b, indexSizes, bmIndexByte(IndexBytePortable))
512}
513
514func bmIndexByte(index func([]byte, byte) int) func(b *testing.B, n int) {
515	return func(b *testing.B, n int) {
516		buf := bmbuf[0:n]
517		buf[n-1] = 'x'
518		for i := 0; i < b.N; i++ {
519			j := index(buf, 'x')
520			if j != n-1 {
521				b.Fatal("bad index", j)
522			}
523		}
524		buf[n-1] = '\x00'
525	}
526}
527
528func BenchmarkIndexRune(b *testing.B) {
529	benchBytes(b, indexSizes, bmIndexRune(IndexRune))
530}
531
532func BenchmarkIndexRuneASCII(b *testing.B) {
533	benchBytes(b, indexSizes, bmIndexRuneASCII(IndexRune))
534}
535
536func bmIndexRuneASCII(index func([]byte, rune) int) func(b *testing.B, n int) {
537	return func(b *testing.B, n int) {
538		buf := bmbuf[0:n]
539		buf[n-1] = 'x'
540		for i := 0; i < b.N; i++ {
541			j := index(buf, 'x')
542			if j != n-1 {
543				b.Fatal("bad index", j)
544			}
545		}
546		buf[n-1] = '\x00'
547	}
548}
549
550func bmIndexRune(index func([]byte, rune) int) func(b *testing.B, n int) {
551	return func(b *testing.B, n int) {
552		buf := bmbuf[0:n]
553		utf8.EncodeRune(buf[n-3:], '世')
554		for i := 0; i < b.N; i++ {
555			j := index(buf, '世')
556			if j != n-3 {
557				b.Fatal("bad index", j)
558			}
559		}
560		buf[n-3] = '\x00'
561		buf[n-2] = '\x00'
562		buf[n-1] = '\x00'
563	}
564}
565
566func BenchmarkEqual(b *testing.B) {
567	b.Run("0", func(b *testing.B) {
568		var buf [4]byte
569		buf1 := buf[0:0]
570		buf2 := buf[1:1]
571		for i := 0; i < b.N; i++ {
572			eq := Equal(buf1, buf2)
573			if !eq {
574				b.Fatal("bad equal")
575			}
576		}
577	})
578
579	sizes := []int{1, 6, 9, 15, 16, 20, 32, 4 << 10, 4 << 20, 64 << 20}
580	benchBytes(b, sizes, bmEqual(Equal))
581}
582
583func BenchmarkEqualPort(b *testing.B) {
584	sizes := []int{1, 6, 32, 4 << 10, 4 << 20, 64 << 20}
585	benchBytes(b, sizes, bmEqual(EqualPortable))
586}
587
588func bmEqual(equal func([]byte, []byte) bool) func(b *testing.B, n int) {
589	return func(b *testing.B, n int) {
590		if len(bmbuf) < 2*n {
591			bmbuf = make([]byte, 2*n)
592		}
593		buf1 := bmbuf[0:n]
594		buf2 := bmbuf[n : 2*n]
595		buf1[n-1] = 'x'
596		buf2[n-1] = 'x'
597		for i := 0; i < b.N; i++ {
598			eq := equal(buf1, buf2)
599			if !eq {
600				b.Fatal("bad equal")
601			}
602		}
603		buf1[n-1] = '\x00'
604		buf2[n-1] = '\x00'
605	}
606}
607
608func BenchmarkIndex(b *testing.B) {
609	benchBytes(b, indexSizes, func(b *testing.B, n int) {
610		buf := bmbuf[0:n]
611		buf[n-1] = 'x'
612		for i := 0; i < b.N; i++ {
613			j := Index(buf, buf[n-7:])
614			if j != n-7 {
615				b.Fatal("bad index", j)
616			}
617		}
618		buf[n-1] = '\x00'
619	})
620}
621
622func BenchmarkIndexEasy(b *testing.B) {
623	benchBytes(b, indexSizes, func(b *testing.B, n int) {
624		buf := bmbuf[0:n]
625		buf[n-1] = 'x'
626		buf[n-7] = 'x'
627		for i := 0; i < b.N; i++ {
628			j := Index(buf, buf[n-7:])
629			if j != n-7 {
630				b.Fatal("bad index", j)
631			}
632		}
633		buf[n-1] = '\x00'
634		buf[n-7] = '\x00'
635	})
636}
637
638func BenchmarkCount(b *testing.B) {
639	benchBytes(b, indexSizes, func(b *testing.B, n int) {
640		buf := bmbuf[0:n]
641		buf[n-1] = 'x'
642		for i := 0; i < b.N; i++ {
643			j := Count(buf, buf[n-7:])
644			if j != 1 {
645				b.Fatal("bad count", j)
646			}
647		}
648		buf[n-1] = '\x00'
649	})
650}
651
652func BenchmarkCountEasy(b *testing.B) {
653	benchBytes(b, indexSizes, func(b *testing.B, n int) {
654		buf := bmbuf[0:n]
655		buf[n-1] = 'x'
656		buf[n-7] = 'x'
657		for i := 0; i < b.N; i++ {
658			j := Count(buf, buf[n-7:])
659			if j != 1 {
660				b.Fatal("bad count", j)
661			}
662		}
663		buf[n-1] = '\x00'
664		buf[n-7] = '\x00'
665	})
666}
667
668func BenchmarkCountSingle(b *testing.B) {
669	benchBytes(b, indexSizes, func(b *testing.B, n int) {
670		buf := bmbuf[0:n]
671		step := 8
672		for i := 0; i < len(buf); i += step {
673			buf[i] = 1
674		}
675		expect := (len(buf) + (step - 1)) / step
676		for i := 0; i < b.N; i++ {
677			j := Count(buf, []byte{1})
678			if j != expect {
679				b.Fatal("bad count", j, expect)
680			}
681		}
682		for i := 0; i < len(buf); i++ {
683			buf[i] = 0
684		}
685	})
686}
687
688type ExplodeTest struct {
689	s string
690	n int
691	a []string
692}
693
694var explodetests = []ExplodeTest{
695	{"", -1, []string{}},
696	{abcd, -1, []string{"a", "b", "c", "d"}},
697	{faces, -1, []string{"☺", "☻", "☹"}},
698	{abcd, 2, []string{"a", "bcd"}},
699}
700
701func TestExplode(t *testing.T) {
702	for _, tt := range explodetests {
703		a := SplitN([]byte(tt.s), nil, tt.n)
704		result := sliceOfString(a)
705		if !eq(result, tt.a) {
706			t.Errorf(`Explode("%s", %d) = %v; want %v`, tt.s, tt.n, result, tt.a)
707			continue
708		}
709		s := Join(a, []byte{})
710		if string(s) != tt.s {
711			t.Errorf(`Join(Explode("%s", %d), "") = "%s"`, tt.s, tt.n, s)
712		}
713	}
714}
715
716type SplitTest struct {
717	s   string
718	sep string
719	n   int
720	a   []string
721}
722
723var splittests = []SplitTest{
724	{abcd, "a", 0, nil},
725	{abcd, "a", -1, []string{"", "bcd"}},
726	{abcd, "z", -1, []string{"abcd"}},
727	{abcd, "", -1, []string{"a", "b", "c", "d"}},
728	{commas, ",", -1, []string{"1", "2", "3", "4"}},
729	{dots, "...", -1, []string{"1", ".2", ".3", ".4"}},
730	{faces, "☹", -1, []string{"☺☻", ""}},
731	{faces, "~", -1, []string{faces}},
732	{faces, "", -1, []string{"☺", "☻", "☹"}},
733	{"1 2 3 4", " ", 3, []string{"1", "2", "3 4"}},
734	{"1 2", " ", 3, []string{"1", "2"}},
735	{"123", "", 2, []string{"1", "23"}},
736	{"123", "", 17, []string{"1", "2", "3"}},
737}
738
739func TestSplit(t *testing.T) {
740	for _, tt := range splittests {
741		a := SplitN([]byte(tt.s), []byte(tt.sep), tt.n)
742
743		// Appending to the results should not change future results.
744		var x []byte
745		for _, v := range a {
746			x = append(v, 'z')
747		}
748
749		result := sliceOfString(a)
750		if !eq(result, tt.a) {
751			t.Errorf(`Split(%q, %q, %d) = %v; want %v`, tt.s, tt.sep, tt.n, result, tt.a)
752			continue
753		}
754		if tt.n == 0 {
755			continue
756		}
757
758		if want := tt.a[len(tt.a)-1] + "z"; string(x) != want {
759			t.Errorf("last appended result was %s; want %s", x, want)
760		}
761
762		s := Join(a, []byte(tt.sep))
763		if string(s) != tt.s {
764			t.Errorf(`Join(Split(%q, %q, %d), %q) = %q`, tt.s, tt.sep, tt.n, tt.sep, s)
765		}
766		if tt.n < 0 {
767			b := Split([]byte(tt.s), []byte(tt.sep))
768			if !reflect.DeepEqual(a, b) {
769				t.Errorf("Split disagrees withSplitN(%q, %q, %d) = %v; want %v", tt.s, tt.sep, tt.n, b, a)
770			}
771		}
772		if len(a) > 0 {
773			in, out := a[0], s
774			if cap(in) == cap(out) && &in[:1][0] == &out[:1][0] {
775				t.Errorf("Join(%#v, %q) didn't copy", a, tt.sep)
776			}
777		}
778	}
779}
780
781var splitaftertests = []SplitTest{
782	{abcd, "a", -1, []string{"a", "bcd"}},
783	{abcd, "z", -1, []string{"abcd"}},
784	{abcd, "", -1, []string{"a", "b", "c", "d"}},
785	{commas, ",", -1, []string{"1,", "2,", "3,", "4"}},
786	{dots, "...", -1, []string{"1...", ".2...", ".3...", ".4"}},
787	{faces, "☹", -1, []string{"☺☻☹", ""}},
788	{faces, "~", -1, []string{faces}},
789	{faces, "", -1, []string{"☺", "☻", "☹"}},
790	{"1 2 3 4", " ", 3, []string{"1 ", "2 ", "3 4"}},
791	{"1 2 3", " ", 3, []string{"1 ", "2 ", "3"}},
792	{"1 2", " ", 3, []string{"1 ", "2"}},
793	{"123", "", 2, []string{"1", "23"}},
794	{"123", "", 17, []string{"1", "2", "3"}},
795}
796
797func TestSplitAfter(t *testing.T) {
798	for _, tt := range splitaftertests {
799		a := SplitAfterN([]byte(tt.s), []byte(tt.sep), tt.n)
800
801		// Appending to the results should not change future results.
802		var x []byte
803		for _, v := range a {
804			x = append(v, 'z')
805		}
806
807		result := sliceOfString(a)
808		if !eq(result, tt.a) {
809			t.Errorf(`Split(%q, %q, %d) = %v; want %v`, tt.s, tt.sep, tt.n, result, tt.a)
810			continue
811		}
812
813		if want := tt.a[len(tt.a)-1] + "z"; string(x) != want {
814			t.Errorf("last appended result was %s; want %s", x, want)
815		}
816
817		s := Join(a, nil)
818		if string(s) != tt.s {
819			t.Errorf(`Join(Split(%q, %q, %d), %q) = %q`, tt.s, tt.sep, tt.n, tt.sep, s)
820		}
821		if tt.n < 0 {
822			b := SplitAfter([]byte(tt.s), []byte(tt.sep))
823			if !reflect.DeepEqual(a, b) {
824				t.Errorf("SplitAfter disagrees withSplitAfterN(%q, %q, %d) = %v; want %v", tt.s, tt.sep, tt.n, b, a)
825			}
826		}
827	}
828}
829
830type FieldsTest struct {
831	s string
832	a []string
833}
834
835var fieldstests = []FieldsTest{
836	{"", []string{}},
837	{" ", []string{}},
838	{" \t ", []string{}},
839	{"  abc  ", []string{"abc"}},
840	{"1 2 3 4", []string{"1", "2", "3", "4"}},
841	{"1  2  3  4", []string{"1", "2", "3", "4"}},
842	{"1\t\t2\t\t3\t4", []string{"1", "2", "3", "4"}},
843	{"1\u20002\u20013\u20024", []string{"1", "2", "3", "4"}},
844	{"\u2000\u2001\u2002", []string{}},
845	{"\n™\t™\n", []string{"™", "™"}},
846	{faces, []string{faces}},
847}
848
849func TestFields(t *testing.T) {
850	for _, tt := range fieldstests {
851		b := []byte(tt.s)
852		a := Fields(b)
853
854		// Appending to the results should not change future results.
855		var x []byte
856		for _, v := range a {
857			x = append(v, 'z')
858		}
859
860		result := sliceOfString(a)
861		if !eq(result, tt.a) {
862			t.Errorf("Fields(%q) = %v; want %v", tt.s, a, tt.a)
863			continue
864		}
865
866		if string(b) != tt.s {
867			t.Errorf("slice changed to %s; want %s", string(b), tt.s)
868		}
869		if len(tt.a) > 0 {
870			if want := tt.a[len(tt.a)-1] + "z"; string(x) != want {
871				t.Errorf("last appended result was %s; want %s", x, want)
872			}
873		}
874	}
875}
876
877func TestFieldsFunc(t *testing.T) {
878	for _, tt := range fieldstests {
879		a := FieldsFunc([]byte(tt.s), unicode.IsSpace)
880		result := sliceOfString(a)
881		if !eq(result, tt.a) {
882			t.Errorf("FieldsFunc(%q, unicode.IsSpace) = %v; want %v", tt.s, a, tt.a)
883			continue
884		}
885	}
886	pred := func(c rune) bool { return c == 'X' }
887	var fieldsFuncTests = []FieldsTest{
888		{"", []string{}},
889		{"XX", []string{}},
890		{"XXhiXXX", []string{"hi"}},
891		{"aXXbXXXcX", []string{"a", "b", "c"}},
892	}
893	for _, tt := range fieldsFuncTests {
894		b := []byte(tt.s)
895		a := FieldsFunc(b, pred)
896
897		// Appending to the results should not change future results.
898		var x []byte
899		for _, v := range a {
900			x = append(v, 'z')
901		}
902
903		result := sliceOfString(a)
904		if !eq(result, tt.a) {
905			t.Errorf("FieldsFunc(%q) = %v, want %v", tt.s, a, tt.a)
906		}
907
908		if string(b) != tt.s {
909			t.Errorf("slice changed to %s; want %s", b, tt.s)
910		}
911		if len(tt.a) > 0 {
912			if want := tt.a[len(tt.a)-1] + "z"; string(x) != want {
913				t.Errorf("last appended result was %s; want %s", x, want)
914			}
915		}
916	}
917}
918
919// Test case for any function which accepts and returns a byte slice.
920// For ease of creation, we write the byte slices as strings.
921type StringTest struct {
922	in, out string
923}
924
925var upperTests = []StringTest{
926	{"", ""},
927	{"abc", "ABC"},
928	{"AbC123", "ABC123"},
929	{"azAZ09_", "AZAZ09_"},
930	{"\u0250\u0250\u0250\u0250\u0250", "\u2C6F\u2C6F\u2C6F\u2C6F\u2C6F"}, // grows one byte per char
931}
932
933var lowerTests = []StringTest{
934	{"", ""},
935	{"abc", "abc"},
936	{"AbC123", "abc123"},
937	{"azAZ09_", "azaz09_"},
938	{"\u2C6D\u2C6D\u2C6D\u2C6D\u2C6D", "\u0251\u0251\u0251\u0251\u0251"}, // shrinks one byte per char
939}
940
941const space = "\t\v\r\f\n\u0085\u00a0\u2000\u3000"
942
943var trimSpaceTests = []StringTest{
944	{"", ""},
945	{"abc", "abc"},
946	{space + "abc" + space, "abc"},
947	{" ", ""},
948	{" \t\r\n \t\t\r\r\n\n ", ""},
949	{" \t\r\n x\t\t\r\r\n\n ", "x"},
950	{" \u2000\t\r\n x\t\t\r\r\ny\n \u3000", "x\t\t\r\r\ny"},
951	{"1 \t\r\n2", "1 \t\r\n2"},
952	{" x\x80", "x\x80"},
953	{" x\xc0", "x\xc0"},
954	{"x \xc0\xc0 ", "x \xc0\xc0"},
955	{"x \xc0", "x \xc0"},
956	{"x \xc0 ", "x \xc0"},
957	{"x \xc0\xc0 ", "x \xc0\xc0"},
958	{"x ☺\xc0\xc0 ", "x ☺\xc0\xc0"},
959	{"x ☺ ", "x ☺"},
960}
961
962// Execute f on each test case.  funcName should be the name of f; it's used
963// in failure reports.
964func runStringTests(t *testing.T, f func([]byte) []byte, funcName string, testCases []StringTest) {
965	for _, tc := range testCases {
966		actual := string(f([]byte(tc.in)))
967		if actual != tc.out {
968			t.Errorf("%s(%q) = %q; want %q", funcName, tc.in, actual, tc.out)
969		}
970	}
971}
972
973func tenRunes(r rune) string {
974	runes := make([]rune, 10)
975	for i := range runes {
976		runes[i] = r
977	}
978	return string(runes)
979}
980
981// User-defined self-inverse mapping function
982func rot13(r rune) rune {
983	const step = 13
984	if r >= 'a' && r <= 'z' {
985		return ((r - 'a' + step) % 26) + 'a'
986	}
987	if r >= 'A' && r <= 'Z' {
988		return ((r - 'A' + step) % 26) + 'A'
989	}
990	return r
991}
992
993func TestMap(t *testing.T) {
994	// Run a couple of awful growth/shrinkage tests
995	a := tenRunes('a')
996
997	// 1.  Grow. This triggers two reallocations in Map.
998	maxRune := func(r rune) rune { return unicode.MaxRune }
999	m := Map(maxRune, []byte(a))
1000	expect := tenRunes(unicode.MaxRune)
1001	if string(m) != expect {
1002		t.Errorf("growing: expected %q got %q", expect, m)
1003	}
1004
1005	// 2. Shrink
1006	minRune := func(r rune) rune { return 'a' }
1007	m = Map(minRune, []byte(tenRunes(unicode.MaxRune)))
1008	expect = a
1009	if string(m) != expect {
1010		t.Errorf("shrinking: expected %q got %q", expect, m)
1011	}
1012
1013	// 3. Rot13
1014	m = Map(rot13, []byte("a to zed"))
1015	expect = "n gb mrq"
1016	if string(m) != expect {
1017		t.Errorf("rot13: expected %q got %q", expect, m)
1018	}
1019
1020	// 4. Rot13^2
1021	m = Map(rot13, Map(rot13, []byte("a to zed")))
1022	expect = "a to zed"
1023	if string(m) != expect {
1024		t.Errorf("rot13: expected %q got %q", expect, m)
1025	}
1026
1027	// 5. Drop
1028	dropNotLatin := func(r rune) rune {
1029		if unicode.Is(unicode.Latin, r) {
1030			return r
1031		}
1032		return -1
1033	}
1034	m = Map(dropNotLatin, []byte("Hello, 세계"))
1035	expect = "Hello"
1036	if string(m) != expect {
1037		t.Errorf("drop: expected %q got %q", expect, m)
1038	}
1039
1040	// 6. Invalid rune
1041	invalidRune := func(r rune) rune {
1042		return utf8.MaxRune + 1
1043	}
1044	m = Map(invalidRune, []byte("x"))
1045	expect = "\uFFFD"
1046	if string(m) != expect {
1047		t.Errorf("invalidRune: expected %q got %q", expect, m)
1048	}
1049}
1050
1051func TestToUpper(t *testing.T) { runStringTests(t, ToUpper, "ToUpper", upperTests) }
1052
1053func TestToLower(t *testing.T) { runStringTests(t, ToLower, "ToLower", lowerTests) }
1054
1055func TestTrimSpace(t *testing.T) { runStringTests(t, TrimSpace, "TrimSpace", trimSpaceTests) }
1056
1057type RepeatTest struct {
1058	in, out string
1059	count   int
1060}
1061
1062var RepeatTests = []RepeatTest{
1063	{"", "", 0},
1064	{"", "", 1},
1065	{"", "", 2},
1066	{"-", "", 0},
1067	{"-", "-", 1},
1068	{"-", "----------", 10},
1069	{"abc ", "abc abc abc ", 3},
1070}
1071
1072func TestRepeat(t *testing.T) {
1073	for _, tt := range RepeatTests {
1074		tin := []byte(tt.in)
1075		tout := []byte(tt.out)
1076		a := Repeat(tin, tt.count)
1077		if !Equal(a, tout) {
1078			t.Errorf("Repeat(%q, %d) = %q; want %q", tin, tt.count, a, tout)
1079			continue
1080		}
1081	}
1082}
1083
1084func repeat(b []byte, count int) (err error) {
1085	defer func() {
1086		if r := recover(); r != nil {
1087			switch v := r.(type) {
1088			case error:
1089				err = v
1090			default:
1091				err = fmt.Errorf("%s", v)
1092			}
1093		}
1094	}()
1095
1096	Repeat(b, count)
1097
1098	return
1099}
1100
1101// See Issue golang.org/issue/16237
1102func TestRepeatCatchesOverflow(t *testing.T) {
1103	tests := [...]struct {
1104		s      string
1105		count  int
1106		errStr string
1107	}{
1108		0: {"--", -2147483647, "negative"},
1109		1: {"", int(^uint(0) >> 1), ""},
1110		2: {"-", 10, ""},
1111		3: {"gopher", 0, ""},
1112		4: {"-", -1, "negative"},
1113		5: {"--", -102, "negative"},
1114		6: {string(make([]byte, 255)), int((^uint(0))/255 + 1), "overflow"},
1115	}
1116
1117	for i, tt := range tests {
1118		err := repeat([]byte(tt.s), tt.count)
1119		if tt.errStr == "" {
1120			if err != nil {
1121				t.Errorf("#%d panicked %v", i, err)
1122			}
1123			continue
1124		}
1125
1126		if err == nil || !strings.Contains(err.Error(), tt.errStr) {
1127			t.Errorf("#%d expected %q got %q", i, tt.errStr, err)
1128		}
1129	}
1130}
1131
1132func runesEqual(a, b []rune) bool {
1133	if len(a) != len(b) {
1134		return false
1135	}
1136	for i, r := range a {
1137		if r != b[i] {
1138			return false
1139		}
1140	}
1141	return true
1142}
1143
1144type RunesTest struct {
1145	in    string
1146	out   []rune
1147	lossy bool
1148}
1149
1150var RunesTests = []RunesTest{
1151	{"", []rune{}, false},
1152	{" ", []rune{32}, false},
1153	{"ABC", []rune{65, 66, 67}, false},
1154	{"abc", []rune{97, 98, 99}, false},
1155	{"\u65e5\u672c\u8a9e", []rune{26085, 26412, 35486}, false},
1156	{"ab\x80c", []rune{97, 98, 0xFFFD, 99}, true},
1157	{"ab\xc0c", []rune{97, 98, 0xFFFD, 99}, true},
1158}
1159
1160func TestRunes(t *testing.T) {
1161	for _, tt := range RunesTests {
1162		tin := []byte(tt.in)
1163		a := Runes(tin)
1164		if !runesEqual(a, tt.out) {
1165			t.Errorf("Runes(%q) = %v; want %v", tin, a, tt.out)
1166			continue
1167		}
1168		if !tt.lossy {
1169			// can only test reassembly if we didn't lose information
1170			s := string(a)
1171			if s != tt.in {
1172				t.Errorf("string(Runes(%q)) = %x; want %x", tin, s, tin)
1173			}
1174		}
1175	}
1176}
1177
1178type TrimTest struct {
1179	f            string
1180	in, arg, out string
1181}
1182
1183var trimTests = []TrimTest{
1184	{"Trim", "abba", "a", "bb"},
1185	{"Trim", "abba", "ab", ""},
1186	{"TrimLeft", "abba", "ab", ""},
1187	{"TrimRight", "abba", "ab", ""},
1188	{"TrimLeft", "abba", "a", "bba"},
1189	{"TrimRight", "abba", "a", "abb"},
1190	{"Trim", "<tag>", "<>", "tag"},
1191	{"Trim", "* listitem", " *", "listitem"},
1192	{"Trim", `"quote"`, `"`, "quote"},
1193	{"Trim", "\u2C6F\u2C6F\u0250\u0250\u2C6F\u2C6F", "\u2C6F", "\u0250\u0250"},
1194	{"Trim", "\x80test\xff", "\xff", "test"},
1195	{"Trim", " Ġ ", " ", "Ġ"},
1196	{"Trim", " Ġİ0", "0 ", "Ġİ"},
1197	//empty string tests
1198	{"Trim", "abba", "", "abba"},
1199	{"Trim", "", "123", ""},
1200	{"Trim", "", "", ""},
1201	{"TrimLeft", "abba", "", "abba"},
1202	{"TrimLeft", "", "123", ""},
1203	{"TrimLeft", "", "", ""},
1204	{"TrimRight", "abba", "", "abba"},
1205	{"TrimRight", "", "123", ""},
1206	{"TrimRight", "", "", ""},
1207	{"TrimRight", "☺\xc0", "☺", "☺\xc0"},
1208	{"TrimPrefix", "aabb", "a", "abb"},
1209	{"TrimPrefix", "aabb", "b", "aabb"},
1210	{"TrimSuffix", "aabb", "a", "aabb"},
1211	{"TrimSuffix", "aabb", "b", "aab"},
1212}
1213
1214func TestTrim(t *testing.T) {
1215	for _, tc := range trimTests {
1216		name := tc.f
1217		var f func([]byte, string) []byte
1218		var fb func([]byte, []byte) []byte
1219		switch name {
1220		case "Trim":
1221			f = Trim
1222		case "TrimLeft":
1223			f = TrimLeft
1224		case "TrimRight":
1225			f = TrimRight
1226		case "TrimPrefix":
1227			fb = TrimPrefix
1228		case "TrimSuffix":
1229			fb = TrimSuffix
1230		default:
1231			t.Errorf("Undefined trim function %s", name)
1232		}
1233		var actual string
1234		if f != nil {
1235			actual = string(f([]byte(tc.in), tc.arg))
1236		} else {
1237			actual = string(fb([]byte(tc.in), []byte(tc.arg)))
1238		}
1239		if actual != tc.out {
1240			t.Errorf("%s(%q, %q) = %q; want %q", name, tc.in, tc.arg, actual, tc.out)
1241		}
1242	}
1243}
1244
1245type predicate struct {
1246	f    func(r rune) bool
1247	name string
1248}
1249
1250var isSpace = predicate{unicode.IsSpace, "IsSpace"}
1251var isDigit = predicate{unicode.IsDigit, "IsDigit"}
1252var isUpper = predicate{unicode.IsUpper, "IsUpper"}
1253var isValidRune = predicate{
1254	func(r rune) bool {
1255		return r != utf8.RuneError
1256	},
1257	"IsValidRune",
1258}
1259
1260type TrimFuncTest struct {
1261	f       predicate
1262	in, out string
1263}
1264
1265func not(p predicate) predicate {
1266	return predicate{
1267		func(r rune) bool {
1268			return !p.f(r)
1269		},
1270		"not " + p.name,
1271	}
1272}
1273
1274var trimFuncTests = []TrimFuncTest{
1275	{isSpace, space + " hello " + space, "hello"},
1276	{isDigit, "\u0e50\u0e5212hello34\u0e50\u0e51", "hello"},
1277	{isUpper, "\u2C6F\u2C6F\u2C6F\u2C6FABCDhelloEF\u2C6F\u2C6FGH\u2C6F\u2C6F", "hello"},
1278	{not(isSpace), "hello" + space + "hello", space},
1279	{not(isDigit), "hello\u0e50\u0e521234\u0e50\u0e51helo", "\u0e50\u0e521234\u0e50\u0e51"},
1280	{isValidRune, "ab\xc0a\xc0cd", "\xc0a\xc0"},
1281	{not(isValidRune), "\xc0a\xc0", "a"},
1282}
1283
1284func TestTrimFunc(t *testing.T) {
1285	for _, tc := range trimFuncTests {
1286		actual := string(TrimFunc([]byte(tc.in), tc.f.f))
1287		if actual != tc.out {
1288			t.Errorf("TrimFunc(%q, %q) = %q; want %q", tc.in, tc.f.name, actual, tc.out)
1289		}
1290	}
1291}
1292
1293type IndexFuncTest struct {
1294	in          string
1295	f           predicate
1296	first, last int
1297}
1298
1299var indexFuncTests = []IndexFuncTest{
1300	{"", isValidRune, -1, -1},
1301	{"abc", isDigit, -1, -1},
1302	{"0123", isDigit, 0, 3},
1303	{"a1b", isDigit, 1, 1},
1304	{space, isSpace, 0, len(space) - 3}, // last rune in space is 3 bytes
1305	{"\u0e50\u0e5212hello34\u0e50\u0e51", isDigit, 0, 18},
1306	{"\u2C6F\u2C6F\u2C6F\u2C6FABCDhelloEF\u2C6F\u2C6FGH\u2C6F\u2C6F", isUpper, 0, 34},
1307	{"12\u0e50\u0e52hello34\u0e50\u0e51", not(isDigit), 8, 12},
1308
1309	// tests of invalid UTF-8
1310	{"\x801", isDigit, 1, 1},
1311	{"\x80abc", isDigit, -1, -1},
1312	{"\xc0a\xc0", isValidRune, 1, 1},
1313	{"\xc0a\xc0", not(isValidRune), 0, 2},
1314	{"\xc0☺\xc0", not(isValidRune), 0, 4},
1315	{"\xc0☺\xc0\xc0", not(isValidRune), 0, 5},
1316	{"ab\xc0a\xc0cd", not(isValidRune), 2, 4},
1317	{"a\xe0\x80cd", not(isValidRune), 1, 2},
1318}
1319
1320func TestIndexFunc(t *testing.T) {
1321	for _, tc := range indexFuncTests {
1322		first := IndexFunc([]byte(tc.in), tc.f.f)
1323		if first != tc.first {
1324			t.Errorf("IndexFunc(%q, %s) = %d; want %d", tc.in, tc.f.name, first, tc.first)
1325		}
1326		last := LastIndexFunc([]byte(tc.in), tc.f.f)
1327		if last != tc.last {
1328			t.Errorf("LastIndexFunc(%q, %s) = %d; want %d", tc.in, tc.f.name, last, tc.last)
1329		}
1330	}
1331}
1332
1333type ReplaceTest struct {
1334	in       string
1335	old, new string
1336	n        int
1337	out      string
1338}
1339
1340var ReplaceTests = []ReplaceTest{
1341	{"hello", "l", "L", 0, "hello"},
1342	{"hello", "l", "L", -1, "heLLo"},
1343	{"hello", "x", "X", -1, "hello"},
1344	{"", "x", "X", -1, ""},
1345	{"radar", "r", "<r>", -1, "<r>ada<r>"},
1346	{"", "", "<>", -1, "<>"},
1347	{"banana", "a", "<>", -1, "b<>n<>n<>"},
1348	{"banana", "a", "<>", 1, "b<>nana"},
1349	{"banana", "a", "<>", 1000, "b<>n<>n<>"},
1350	{"banana", "an", "<>", -1, "b<><>a"},
1351	{"banana", "ana", "<>", -1, "b<>na"},
1352	{"banana", "", "<>", -1, "<>b<>a<>n<>a<>n<>a<>"},
1353	{"banana", "", "<>", 10, "<>b<>a<>n<>a<>n<>a<>"},
1354	{"banana", "", "<>", 6, "<>b<>a<>n<>a<>n<>a"},
1355	{"banana", "", "<>", 5, "<>b<>a<>n<>a<>na"},
1356	{"banana", "", "<>", 1, "<>banana"},
1357	{"banana", "a", "a", -1, "banana"},
1358	{"banana", "a", "a", 1, "banana"},
1359	{"☺☻☹", "", "<>", -1, "<>☺<>☻<>☹<>"},
1360}
1361
1362func TestReplace(t *testing.T) {
1363	for _, tt := range ReplaceTests {
1364		in := append([]byte(tt.in), "<spare>"...)
1365		in = in[:len(tt.in)]
1366		out := Replace(in, []byte(tt.old), []byte(tt.new), tt.n)
1367		if s := string(out); s != tt.out {
1368			t.Errorf("Replace(%q, %q, %q, %d) = %q, want %q", tt.in, tt.old, tt.new, tt.n, s, tt.out)
1369		}
1370		if cap(in) == cap(out) && &in[:1][0] == &out[:1][0] {
1371			t.Errorf("Replace(%q, %q, %q, %d) didn't copy", tt.in, tt.old, tt.new, tt.n)
1372		}
1373	}
1374}
1375
1376type TitleTest struct {
1377	in, out string
1378}
1379
1380var TitleTests = []TitleTest{
1381	{"", ""},
1382	{"a", "A"},
1383	{" aaa aaa aaa ", " Aaa Aaa Aaa "},
1384	{" Aaa Aaa Aaa ", " Aaa Aaa Aaa "},
1385	{"123a456", "123a456"},
1386	{"double-blind", "Double-Blind"},
1387	{"ÿøû", "Ÿøû"},
1388	{"with_underscore", "With_underscore"},
1389	{"unicode \xe2\x80\xa8 line separator", "Unicode \xe2\x80\xa8 Line Separator"},
1390}
1391
1392func TestTitle(t *testing.T) {
1393	for _, tt := range TitleTests {
1394		if s := string(Title([]byte(tt.in))); s != tt.out {
1395			t.Errorf("Title(%q) = %q, want %q", tt.in, s, tt.out)
1396		}
1397	}
1398}
1399
1400var ToTitleTests = []TitleTest{
1401	{"", ""},
1402	{"a", "A"},
1403	{" aaa aaa aaa ", " AAA AAA AAA "},
1404	{" Aaa Aaa Aaa ", " AAA AAA AAA "},
1405	{"123a456", "123A456"},
1406	{"double-blind", "DOUBLE-BLIND"},
1407	{"ÿøû", "ŸØÛ"},
1408}
1409
1410func TestToTitle(t *testing.T) {
1411	for _, tt := range ToTitleTests {
1412		if s := string(ToTitle([]byte(tt.in))); s != tt.out {
1413			t.Errorf("ToTitle(%q) = %q, want %q", tt.in, s, tt.out)
1414		}
1415	}
1416}
1417
1418var EqualFoldTests = []struct {
1419	s, t string
1420	out  bool
1421}{
1422	{"abc", "abc", true},
1423	{"ABcd", "ABcd", true},
1424	{"123abc", "123ABC", true},
1425	{"αβδ", "ΑΒΔ", true},
1426	{"abc", "xyz", false},
1427	{"abc", "XYZ", false},
1428	{"abcdefghijk", "abcdefghijX", false},
1429	{"abcdefghijk", "abcdefghij\u212A", true},
1430	{"abcdefghijK", "abcdefghij\u212A", true},
1431	{"abcdefghijkz", "abcdefghij\u212Ay", false},
1432	{"abcdefghijKz", "abcdefghij\u212Ay", false},
1433}
1434
1435func TestEqualFold(t *testing.T) {
1436	for _, tt := range EqualFoldTests {
1437		if out := EqualFold([]byte(tt.s), []byte(tt.t)); out != tt.out {
1438			t.Errorf("EqualFold(%#q, %#q) = %v, want %v", tt.s, tt.t, out, tt.out)
1439		}
1440		if out := EqualFold([]byte(tt.t), []byte(tt.s)); out != tt.out {
1441			t.Errorf("EqualFold(%#q, %#q) = %v, want %v", tt.t, tt.s, out, tt.out)
1442		}
1443	}
1444}
1445
1446func TestBufferGrowNegative(t *testing.T) {
1447	defer func() {
1448		if err := recover(); err == nil {
1449			t.Fatal("Grow(-1) should have panicked")
1450		}
1451	}()
1452	var b Buffer
1453	b.Grow(-1)
1454}
1455
1456func TestBufferTruncateNegative(t *testing.T) {
1457	defer func() {
1458		if err := recover(); err == nil {
1459			t.Fatal("Truncate(-1) should have panicked")
1460		}
1461	}()
1462	var b Buffer
1463	b.Truncate(-1)
1464}
1465
1466func TestBufferTruncateOutOfRange(t *testing.T) {
1467	defer func() {
1468		if err := recover(); err == nil {
1469			t.Fatal("Truncate(20) should have panicked")
1470		}
1471	}()
1472	var b Buffer
1473	b.Write(make([]byte, 10))
1474	b.Truncate(20)
1475}
1476
1477var containsTests = []struct {
1478	b, subslice []byte
1479	want        bool
1480}{
1481	{[]byte("hello"), []byte("hel"), true},
1482	{[]byte("日本語"), []byte("日本"), true},
1483	{[]byte("hello"), []byte("Hello, world"), false},
1484	{[]byte("東京"), []byte("京東"), false},
1485}
1486
1487func TestContains(t *testing.T) {
1488	for _, tt := range containsTests {
1489		if got := Contains(tt.b, tt.subslice); got != tt.want {
1490			t.Errorf("Contains(%q, %q) = %v, want %v", tt.b, tt.subslice, got, tt.want)
1491		}
1492	}
1493}
1494
1495var ContainsAnyTests = []struct {
1496	b        []byte
1497	substr   string
1498	expected bool
1499}{
1500	{[]byte(""), "", false},
1501	{[]byte(""), "a", false},
1502	{[]byte(""), "abc", false},
1503	{[]byte("a"), "", false},
1504	{[]byte("a"), "a", true},
1505	{[]byte("aaa"), "a", true},
1506	{[]byte("abc"), "xyz", false},
1507	{[]byte("abc"), "xcz", true},
1508	{[]byte("a☺b☻c☹d"), "uvw☻xyz", true},
1509	{[]byte("aRegExp*"), ".(|)*+?^$[]", true},
1510	{[]byte(dots + dots + dots), " ", false},
1511}
1512
1513func TestContainsAny(t *testing.T) {
1514	for _, ct := range ContainsAnyTests {
1515		if ContainsAny(ct.b, ct.substr) != ct.expected {
1516			t.Errorf("ContainsAny(%s, %s) = %v, want %v",
1517				ct.b, ct.substr, !ct.expected, ct.expected)
1518		}
1519	}
1520}
1521
1522var ContainsRuneTests = []struct {
1523	b        []byte
1524	r        rune
1525	expected bool
1526}{
1527	{[]byte(""), 'a', false},
1528	{[]byte("a"), 'a', true},
1529	{[]byte("aaa"), 'a', true},
1530	{[]byte("abc"), 'y', false},
1531	{[]byte("abc"), 'c', true},
1532	{[]byte("a☺b☻c☹d"), 'x', false},
1533	{[]byte("a☺b☻c☹d"), '☻', true},
1534	{[]byte("aRegExp*"), '*', true},
1535}
1536
1537func TestContainsRune(t *testing.T) {
1538	for _, ct := range ContainsRuneTests {
1539		if ContainsRune(ct.b, ct.r) != ct.expected {
1540			t.Errorf("ContainsRune(%q, %q) = %v, want %v",
1541				ct.b, ct.r, !ct.expected, ct.expected)
1542		}
1543	}
1544}
1545
1546var makeFieldsInput = func() []byte {
1547	x := make([]byte, 1<<20)
1548	// Input is ~10% space, ~10% 2-byte UTF-8, rest ASCII non-space.
1549	for i := range x {
1550		switch rand.Intn(10) {
1551		case 0:
1552			x[i] = ' '
1553		case 1:
1554			if i > 0 && x[i-1] == 'x' {
1555				copy(x[i-1:], "χ")
1556				break
1557			}
1558			fallthrough
1559		default:
1560			x[i] = 'x'
1561		}
1562	}
1563	return x
1564}
1565
1566var makeFieldsInputASCII = func() []byte {
1567	x := make([]byte, 1<<20)
1568	// Input is ~10% space, rest ASCII non-space.
1569	for i := range x {
1570		if rand.Intn(10) == 0 {
1571			x[i] = ' '
1572		} else {
1573			x[i] = 'x'
1574		}
1575	}
1576	return x
1577}
1578
1579var bytesdata = []struct {
1580	name string
1581	data []byte
1582}{
1583	{"ASCII", makeFieldsInputASCII()},
1584	{"Mixed", makeFieldsInput()},
1585}
1586
1587func BenchmarkFields(b *testing.B) {
1588	for _, sd := range bytesdata {
1589		b.Run(sd.name, func(b *testing.B) {
1590			for j := 1 << 4; j <= 1<<20; j <<= 4 {
1591				b.Run(fmt.Sprintf("%d", j), func(b *testing.B) {
1592					b.ReportAllocs()
1593					b.SetBytes(int64(j))
1594					data := sd.data[:j]
1595					for i := 0; i < b.N; i++ {
1596						Fields(data)
1597					}
1598				})
1599			}
1600		})
1601	}
1602}
1603
1604func BenchmarkFieldsFunc(b *testing.B) {
1605	for _, sd := range bytesdata {
1606		b.Run(sd.name, func(b *testing.B) {
1607			for j := 1 << 4; j <= 1<<20; j <<= 4 {
1608				b.Run(fmt.Sprintf("%d", j), func(b *testing.B) {
1609					b.ReportAllocs()
1610					b.SetBytes(int64(j))
1611					data := sd.data[:j]
1612					for i := 0; i < b.N; i++ {
1613						FieldsFunc(data, unicode.IsSpace)
1614					}
1615				})
1616			}
1617		})
1618	}
1619}
1620
1621func BenchmarkTrimSpace(b *testing.B) {
1622	s := []byte("  Some text.  \n")
1623	for i := 0; i < b.N; i++ {
1624		TrimSpace(s)
1625	}
1626}
1627
1628func makeBenchInputHard() []byte {
1629	tokens := [...]string{
1630		"<a>", "<p>", "<b>", "<strong>",
1631		"</a>", "</p>", "</b>", "</strong>",
1632		"hello", "world",
1633	}
1634	x := make([]byte, 0, 1<<20)
1635	for {
1636		i := rand.Intn(len(tokens))
1637		if len(x)+len(tokens[i]) >= 1<<20 {
1638			break
1639		}
1640		x = append(x, tokens[i]...)
1641	}
1642	return x
1643}
1644
1645var benchInputHard = makeBenchInputHard()
1646
1647func BenchmarkSplitEmptySeparator(b *testing.B) {
1648	for i := 0; i < b.N; i++ {
1649		Split(benchInputHard, nil)
1650	}
1651}
1652
1653func BenchmarkSplitSingleByteSeparator(b *testing.B) {
1654	sep := []byte("/")
1655	for i := 0; i < b.N; i++ {
1656		Split(benchInputHard, sep)
1657	}
1658}
1659
1660func BenchmarkSplitMultiByteSeparator(b *testing.B) {
1661	sep := []byte("hello")
1662	for i := 0; i < b.N; i++ {
1663		Split(benchInputHard, sep)
1664	}
1665}
1666
1667func BenchmarkSplitNSingleByteSeparator(b *testing.B) {
1668	sep := []byte("/")
1669	for i := 0; i < b.N; i++ {
1670		SplitN(benchInputHard, sep, 10)
1671	}
1672}
1673
1674func BenchmarkSplitNMultiByteSeparator(b *testing.B) {
1675	sep := []byte("hello")
1676	for i := 0; i < b.N; i++ {
1677		SplitN(benchInputHard, sep, 10)
1678	}
1679}
1680
1681func BenchmarkRepeat(b *testing.B) {
1682	for i := 0; i < b.N; i++ {
1683		Repeat([]byte("-"), 80)
1684	}
1685}
1686
1687func BenchmarkBytesCompare(b *testing.B) {
1688	for n := 1; n <= 2048; n <<= 1 {
1689		b.Run(fmt.Sprint(n), func(b *testing.B) {
1690			var x = make([]byte, n)
1691			var y = make([]byte, n)
1692
1693			for i := 0; i < n; i++ {
1694				x[i] = 'a'
1695			}
1696
1697			for i := 0; i < n; i++ {
1698				y[i] = 'a'
1699			}
1700
1701			b.ResetTimer()
1702			for i := 0; i < b.N; i++ {
1703				Compare(x, y)
1704			}
1705		})
1706	}
1707}
1708
1709func BenchmarkIndexAnyASCII(b *testing.B) {
1710	x := Repeat([]byte{'#'}, 4096) // Never matches set
1711	cs := "0123456789abcdef"
1712	for k := 1; k <= 4096; k <<= 4 {
1713		for j := 1; j <= 16; j <<= 1 {
1714			b.Run(fmt.Sprintf("%d:%d", k, j), func(b *testing.B) {
1715				for i := 0; i < b.N; i++ {
1716					IndexAny(x[:k], cs[:j])
1717				}
1718			})
1719		}
1720	}
1721}
1722
1723func BenchmarkTrimASCII(b *testing.B) {
1724	cs := "0123456789abcdef"
1725	for k := 1; k <= 4096; k <<= 4 {
1726		for j := 1; j <= 16; j <<= 1 {
1727			b.Run(fmt.Sprintf("%d:%d", k, j), func(b *testing.B) {
1728				x := Repeat([]byte(cs[:j]), k) // Always matches set
1729				for i := 0; i < b.N; i++ {
1730					Trim(x[:k], cs[:j])
1731				}
1732			})
1733		}
1734	}
1735}
1736
1737func BenchmarkIndexPeriodic(b *testing.B) {
1738	key := []byte{1, 1}
1739	for _, skip := range [...]int{2, 4, 8, 16, 32, 64} {
1740		b.Run(fmt.Sprintf("IndexPeriodic%d", skip), func(b *testing.B) {
1741			buf := make([]byte, 1<<16)
1742			for i := 0; i < len(buf); i += skip {
1743				buf[i] = 1
1744			}
1745			for i := 0; i < b.N; i++ {
1746				Index(buf, key)
1747			}
1748		})
1749	}
1750}
1751