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Source file src/bytes/bytes_test.go

Documentation: bytes

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

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