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Source file src/regexp/all_test.go

Documentation: regexp

		 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 regexp
		 6  
		 7  import (
		 8  	"reflect"
		 9  	"regexp/syntax"
		10  	"strings"
		11  	"testing"
		12  	"unicode/utf8"
		13  )
		14  
		15  var goodRe = []string{
		16  	``,
		17  	`.`,
		18  	`^.$`,
		19  	`a`,
		20  	`a*`,
		21  	`a+`,
		22  	`a?`,
		23  	`a|b`,
		24  	`a*|b*`,
		25  	`(a*|b)(c*|d)`,
		26  	`[a-z]`,
		27  	`[a-abc-c\-\]\[]`,
		28  	`[a-z]+`,
		29  	`[abc]`,
		30  	`[^1234]`,
		31  	`[^\n]`,
		32  	`\!\\`,
		33  }
		34  
		35  type stringError struct {
		36  	re	string
		37  	err string
		38  }
		39  
		40  var badRe = []stringError{
		41  	{`*`, "missing argument to repetition operator: `*`"},
		42  	{`+`, "missing argument to repetition operator: `+`"},
		43  	{`?`, "missing argument to repetition operator: `?`"},
		44  	{`(abc`, "missing closing ): `(abc`"},
		45  	{`abc)`, "unexpected ): `abc)`"},
		46  	{`x[a-z`, "missing closing ]: `[a-z`"},
		47  	{`[z-a]`, "invalid character class range: `z-a`"},
		48  	{`abc\`, "trailing backslash at end of expression"},
		49  	{`a**`, "invalid nested repetition operator: `**`"},
		50  	{`a*+`, "invalid nested repetition operator: `*+`"},
		51  	{`\x`, "invalid escape sequence: `\\x`"},
		52  }
		53  
		54  func compileTest(t *testing.T, expr string, error string) *Regexp {
		55  	re, err := Compile(expr)
		56  	if error == "" && err != nil {
		57  		t.Error("compiling `", expr, "`; unexpected error: ", err.Error())
		58  	}
		59  	if error != "" && err == nil {
		60  		t.Error("compiling `", expr, "`; missing error")
		61  	} else if error != "" && !strings.Contains(err.Error(), error) {
		62  		t.Error("compiling `", expr, "`; wrong error: ", err.Error(), "; want ", error)
		63  	}
		64  	return re
		65  }
		66  
		67  func TestGoodCompile(t *testing.T) {
		68  	for i := 0; i < len(goodRe); i++ {
		69  		compileTest(t, goodRe[i], "")
		70  	}
		71  }
		72  
		73  func TestBadCompile(t *testing.T) {
		74  	for i := 0; i < len(badRe); i++ {
		75  		compileTest(t, badRe[i].re, badRe[i].err)
		76  	}
		77  }
		78  
		79  func matchTest(t *testing.T, test *FindTest) {
		80  	re := compileTest(t, test.pat, "")
		81  	if re == nil {
		82  		return
		83  	}
		84  	m := re.MatchString(test.text)
		85  	if m != (len(test.matches) > 0) {
		86  		t.Errorf("MatchString failure on %s: %t should be %t", test, m, len(test.matches) > 0)
		87  	}
		88  	// now try bytes
		89  	m = re.Match([]byte(test.text))
		90  	if m != (len(test.matches) > 0) {
		91  		t.Errorf("Match failure on %s: %t should be %t", test, m, len(test.matches) > 0)
		92  	}
		93  }
		94  
		95  func TestMatch(t *testing.T) {
		96  	for _, test := range findTests {
		97  		matchTest(t, &test)
		98  	}
		99  }
	 100  
	 101  func matchFunctionTest(t *testing.T, test *FindTest) {
	 102  	m, err := MatchString(test.pat, test.text)
	 103  	if err == nil {
	 104  		return
	 105  	}
	 106  	if m != (len(test.matches) > 0) {
	 107  		t.Errorf("Match failure on %s: %t should be %t", test, m, len(test.matches) > 0)
	 108  	}
	 109  }
	 110  
	 111  func TestMatchFunction(t *testing.T) {
	 112  	for _, test := range findTests {
	 113  		matchFunctionTest(t, &test)
	 114  	}
	 115  }
	 116  
	 117  func copyMatchTest(t *testing.T, test *FindTest) {
	 118  	re := compileTest(t, test.pat, "")
	 119  	if re == nil {
	 120  		return
	 121  	}
	 122  	m1 := re.MatchString(test.text)
	 123  	m2 := re.Copy().MatchString(test.text)
	 124  	if m1 != m2 {
	 125  		t.Errorf("Copied Regexp match failure on %s: original gave %t; copy gave %t; should be %t",
	 126  			test, m1, m2, len(test.matches) > 0)
	 127  	}
	 128  }
	 129  
	 130  func TestCopyMatch(t *testing.T) {
	 131  	for _, test := range findTests {
	 132  		copyMatchTest(t, &test)
	 133  	}
	 134  }
	 135  
	 136  type ReplaceTest struct {
	 137  	pattern, replacement, input, output string
	 138  }
	 139  
	 140  var replaceTests = []ReplaceTest{
	 141  	// Test empty input and/or replacement, with pattern that matches the empty string.
	 142  	{"", "", "", ""},
	 143  	{"", "x", "", "x"},
	 144  	{"", "", "abc", "abc"},
	 145  	{"", "x", "abc", "xaxbxcx"},
	 146  
	 147  	// Test empty input and/or replacement, with pattern that does not match the empty string.
	 148  	{"b", "", "", ""},
	 149  	{"b", "x", "", ""},
	 150  	{"b", "", "abc", "ac"},
	 151  	{"b", "x", "abc", "axc"},
	 152  	{"y", "", "", ""},
	 153  	{"y", "x", "", ""},
	 154  	{"y", "", "abc", "abc"},
	 155  	{"y", "x", "abc", "abc"},
	 156  
	 157  	// Multibyte characters -- verify that we don't try to match in the middle
	 158  	// of a character.
	 159  	{"[a-c]*", "x", "\u65e5", "x\u65e5x"},
	 160  	{"[^\u65e5]", "x", "abc\u65e5def", "xxx\u65e5xxx"},
	 161  
	 162  	// Start and end of a string.
	 163  	{"^[a-c]*", "x", "abcdabc", "xdabc"},
	 164  	{"[a-c]*$", "x", "abcdabc", "abcdx"},
	 165  	{"^[a-c]*$", "x", "abcdabc", "abcdabc"},
	 166  	{"^[a-c]*", "x", "abc", "x"},
	 167  	{"[a-c]*$", "x", "abc", "x"},
	 168  	{"^[a-c]*$", "x", "abc", "x"},
	 169  	{"^[a-c]*", "x", "dabce", "xdabce"},
	 170  	{"[a-c]*$", "x", "dabce", "dabcex"},
	 171  	{"^[a-c]*$", "x", "dabce", "dabce"},
	 172  	{"^[a-c]*", "x", "", "x"},
	 173  	{"[a-c]*$", "x", "", "x"},
	 174  	{"^[a-c]*$", "x", "", "x"},
	 175  
	 176  	{"^[a-c]+", "x", "abcdabc", "xdabc"},
	 177  	{"[a-c]+$", "x", "abcdabc", "abcdx"},
	 178  	{"^[a-c]+$", "x", "abcdabc", "abcdabc"},
	 179  	{"^[a-c]+", "x", "abc", "x"},
	 180  	{"[a-c]+$", "x", "abc", "x"},
	 181  	{"^[a-c]+$", "x", "abc", "x"},
	 182  	{"^[a-c]+", "x", "dabce", "dabce"},
	 183  	{"[a-c]+$", "x", "dabce", "dabce"},
	 184  	{"^[a-c]+$", "x", "dabce", "dabce"},
	 185  	{"^[a-c]+", "x", "", ""},
	 186  	{"[a-c]+$", "x", "", ""},
	 187  	{"^[a-c]+$", "x", "", ""},
	 188  
	 189  	// Other cases.
	 190  	{"abc", "def", "abcdefg", "defdefg"},
	 191  	{"bc", "BC", "abcbcdcdedef", "aBCBCdcdedef"},
	 192  	{"abc", "", "abcdabc", "d"},
	 193  	{"x", "xXx", "xxxXxxx", "xXxxXxxXxXxXxxXxxXx"},
	 194  	{"abc", "d", "", ""},
	 195  	{"abc", "d", "abc", "d"},
	 196  	{".+", "x", "abc", "x"},
	 197  	{"[a-c]*", "x", "def", "xdxexfx"},
	 198  	{"[a-c]+", "x", "abcbcdcdedef", "xdxdedef"},
	 199  	{"[a-c]*", "x", "abcbcdcdedef", "xdxdxexdxexfx"},
	 200  
	 201  	// Substitutions
	 202  	{"a+", "($0)", "banana", "b(a)n(a)n(a)"},
	 203  	{"a+", "(${0})", "banana", "b(a)n(a)n(a)"},
	 204  	{"a+", "(${0})$0", "banana", "b(a)an(a)an(a)a"},
	 205  	{"a+", "(${0})$0", "banana", "b(a)an(a)an(a)a"},
	 206  	{"hello, (.+)", "goodbye, ${1}", "hello, world", "goodbye, world"},
	 207  	{"hello, (.+)", "goodbye, $1x", "hello, world", "goodbye, "},
	 208  	{"hello, (.+)", "goodbye, ${1}x", "hello, world", "goodbye, worldx"},
	 209  	{"hello, (.+)", "<$0><$1><$2><$3>", "hello, world", "<hello, world><world><><>"},
	 210  	{"hello, (?P<noun>.+)", "goodbye, $noun!", "hello, world", "goodbye, world!"},
	 211  	{"hello, (?P<noun>.+)", "goodbye, ${noun}", "hello, world", "goodbye, world"},
	 212  	{"(?P<x>hi)|(?P<x>bye)", "$x$x$x", "hi", "hihihi"},
	 213  	{"(?P<x>hi)|(?P<x>bye)", "$x$x$x", "bye", "byebyebye"},
	 214  	{"(?P<x>hi)|(?P<x>bye)", "$xyz", "hi", ""},
	 215  	{"(?P<x>hi)|(?P<x>bye)", "${x}yz", "hi", "hiyz"},
	 216  	{"(?P<x>hi)|(?P<x>bye)", "hello $$x", "hi", "hello $x"},
	 217  	{"a+", "${oops", "aaa", "${oops"},
	 218  	{"a+", "$$", "aaa", "$"},
	 219  	{"a+", "$", "aaa", "$"},
	 220  
	 221  	// Substitution when subexpression isn't found
	 222  	{"(x)?", "$1", "123", "123"},
	 223  	{"abc", "$1", "123", "123"},
	 224  
	 225  	// Substitutions involving a (x){0}
	 226  	{"(a)(b){0}(c)", ".$1|$3.", "xacxacx", "x.a|c.x.a|c.x"},
	 227  	{"(a)(((b))){0}c", ".$1.", "xacxacx", "x.a.x.a.x"},
	 228  	{"((a(b){0}){3}){5}(h)", "y caramb$2", "say aaaaaaaaaaaaaaaah", "say ay caramba"},
	 229  	{"((a(b){0}){3}){5}h", "y caramb$2", "say aaaaaaaaaaaaaaaah", "say ay caramba"},
	 230  }
	 231  
	 232  var replaceLiteralTests = []ReplaceTest{
	 233  	// Substitutions
	 234  	{"a+", "($0)", "banana", "b($0)n($0)n($0)"},
	 235  	{"a+", "(${0})", "banana", "b(${0})n(${0})n(${0})"},
	 236  	{"a+", "(${0})$0", "banana", "b(${0})$0n(${0})$0n(${0})$0"},
	 237  	{"a+", "(${0})$0", "banana", "b(${0})$0n(${0})$0n(${0})$0"},
	 238  	{"hello, (.+)", "goodbye, ${1}", "hello, world", "goodbye, ${1}"},
	 239  	{"hello, (?P<noun>.+)", "goodbye, $noun!", "hello, world", "goodbye, $noun!"},
	 240  	{"hello, (?P<noun>.+)", "goodbye, ${noun}", "hello, world", "goodbye, ${noun}"},
	 241  	{"(?P<x>hi)|(?P<x>bye)", "$x$x$x", "hi", "$x$x$x"},
	 242  	{"(?P<x>hi)|(?P<x>bye)", "$x$x$x", "bye", "$x$x$x"},
	 243  	{"(?P<x>hi)|(?P<x>bye)", "$xyz", "hi", "$xyz"},
	 244  	{"(?P<x>hi)|(?P<x>bye)", "${x}yz", "hi", "${x}yz"},
	 245  	{"(?P<x>hi)|(?P<x>bye)", "hello $$x", "hi", "hello $$x"},
	 246  	{"a+", "${oops", "aaa", "${oops"},
	 247  	{"a+", "$$", "aaa", "$$"},
	 248  	{"a+", "$", "aaa", "$"},
	 249  }
	 250  
	 251  type ReplaceFuncTest struct {
	 252  	pattern			 string
	 253  	replacement	 func(string) string
	 254  	input, output string
	 255  }
	 256  
	 257  var replaceFuncTests = []ReplaceFuncTest{
	 258  	{"[a-c]", func(s string) string { return "x" + s + "y" }, "defabcdef", "defxayxbyxcydef"},
	 259  	{"[a-c]+", func(s string) string { return "x" + s + "y" }, "defabcdef", "defxabcydef"},
	 260  	{"[a-c]*", func(s string) string { return "x" + s + "y" }, "defabcdef", "xydxyexyfxabcydxyexyfxy"},
	 261  }
	 262  
	 263  func TestReplaceAll(t *testing.T) {
	 264  	for _, tc := range replaceTests {
	 265  		re, err := Compile(tc.pattern)
	 266  		if err != nil {
	 267  			t.Errorf("Unexpected error compiling %q: %v", tc.pattern, err)
	 268  			continue
	 269  		}
	 270  		actual := re.ReplaceAllString(tc.input, tc.replacement)
	 271  		if actual != tc.output {
	 272  			t.Errorf("%q.ReplaceAllString(%q,%q) = %q; want %q",
	 273  				tc.pattern, tc.input, tc.replacement, actual, tc.output)
	 274  		}
	 275  		// now try bytes
	 276  		actual = string(re.ReplaceAll([]byte(tc.input), []byte(tc.replacement)))
	 277  		if actual != tc.output {
	 278  			t.Errorf("%q.ReplaceAll(%q,%q) = %q; want %q",
	 279  				tc.pattern, tc.input, tc.replacement, actual, tc.output)
	 280  		}
	 281  	}
	 282  }
	 283  
	 284  func TestReplaceAllLiteral(t *testing.T) {
	 285  	// Run ReplaceAll tests that do not have $ expansions.
	 286  	for _, tc := range replaceTests {
	 287  		if strings.Contains(tc.replacement, "$") {
	 288  			continue
	 289  		}
	 290  		re, err := Compile(tc.pattern)
	 291  		if err != nil {
	 292  			t.Errorf("Unexpected error compiling %q: %v", tc.pattern, err)
	 293  			continue
	 294  		}
	 295  		actual := re.ReplaceAllLiteralString(tc.input, tc.replacement)
	 296  		if actual != tc.output {
	 297  			t.Errorf("%q.ReplaceAllLiteralString(%q,%q) = %q; want %q",
	 298  				tc.pattern, tc.input, tc.replacement, actual, tc.output)
	 299  		}
	 300  		// now try bytes
	 301  		actual = string(re.ReplaceAllLiteral([]byte(tc.input), []byte(tc.replacement)))
	 302  		if actual != tc.output {
	 303  			t.Errorf("%q.ReplaceAllLiteral(%q,%q) = %q; want %q",
	 304  				tc.pattern, tc.input, tc.replacement, actual, tc.output)
	 305  		}
	 306  	}
	 307  
	 308  	// Run literal-specific tests.
	 309  	for _, tc := range replaceLiteralTests {
	 310  		re, err := Compile(tc.pattern)
	 311  		if err != nil {
	 312  			t.Errorf("Unexpected error compiling %q: %v", tc.pattern, err)
	 313  			continue
	 314  		}
	 315  		actual := re.ReplaceAllLiteralString(tc.input, tc.replacement)
	 316  		if actual != tc.output {
	 317  			t.Errorf("%q.ReplaceAllLiteralString(%q,%q) = %q; want %q",
	 318  				tc.pattern, tc.input, tc.replacement, actual, tc.output)
	 319  		}
	 320  		// now try bytes
	 321  		actual = string(re.ReplaceAllLiteral([]byte(tc.input), []byte(tc.replacement)))
	 322  		if actual != tc.output {
	 323  			t.Errorf("%q.ReplaceAllLiteral(%q,%q) = %q; want %q",
	 324  				tc.pattern, tc.input, tc.replacement, actual, tc.output)
	 325  		}
	 326  	}
	 327  }
	 328  
	 329  func TestReplaceAllFunc(t *testing.T) {
	 330  	for _, tc := range replaceFuncTests {
	 331  		re, err := Compile(tc.pattern)
	 332  		if err != nil {
	 333  			t.Errorf("Unexpected error compiling %q: %v", tc.pattern, err)
	 334  			continue
	 335  		}
	 336  		actual := re.ReplaceAllStringFunc(tc.input, tc.replacement)
	 337  		if actual != tc.output {
	 338  			t.Errorf("%q.ReplaceFunc(%q,fn) = %q; want %q",
	 339  				tc.pattern, tc.input, actual, tc.output)
	 340  		}
	 341  		// now try bytes
	 342  		actual = string(re.ReplaceAllFunc([]byte(tc.input), func(s []byte) []byte { return []byte(tc.replacement(string(s))) }))
	 343  		if actual != tc.output {
	 344  			t.Errorf("%q.ReplaceFunc(%q,fn) = %q; want %q",
	 345  				tc.pattern, tc.input, actual, tc.output)
	 346  		}
	 347  	}
	 348  }
	 349  
	 350  type MetaTest struct {
	 351  	pattern, output, literal string
	 352  	isLiteral								bool
	 353  }
	 354  
	 355  var metaTests = []MetaTest{
	 356  	{``, ``, ``, true},
	 357  	{`foo`, `foo`, `foo`, true},
	 358  	{`日本語+`, `日本語\+`, `日本語`, false},
	 359  	{`foo\.\$`, `foo\\\.\\\$`, `foo.$`, true}, // has meta but no operator
	 360  	{`foo.\$`, `foo\.\\\$`, `foo`, false},		 // has escaped operators and real operators
	 361  	{`!@#$%^&*()_+-=[{]}\|,<.>/?~`, `!@#\$%\^&\*\(\)_\+-=\[\{\]\}\\\|,<\.>/\?~`, `!@#`, false},
	 362  }
	 363  
	 364  var literalPrefixTests = []MetaTest{
	 365  	// See golang.org/issue/11175.
	 366  	// output is unused.
	 367  	{`^0^0$`, ``, `0`, false},
	 368  	{`^0^`, ``, ``, false},
	 369  	{`^0$`, ``, `0`, true},
	 370  	{`$0^`, ``, ``, false},
	 371  	{`$0$`, ``, ``, false},
	 372  	{`^^0$$`, ``, ``, false},
	 373  	{`^$^$`, ``, ``, false},
	 374  	{`$$0^^`, ``, ``, false},
	 375  }
	 376  
	 377  func TestQuoteMeta(t *testing.T) {
	 378  	for _, tc := range metaTests {
	 379  		// Verify that QuoteMeta returns the expected string.
	 380  		quoted := QuoteMeta(tc.pattern)
	 381  		if quoted != tc.output {
	 382  			t.Errorf("QuoteMeta(`%s`) = `%s`; want `%s`",
	 383  				tc.pattern, quoted, tc.output)
	 384  			continue
	 385  		}
	 386  
	 387  		// Verify that the quoted string is in fact treated as expected
	 388  		// by Compile -- i.e. that it matches the original, unquoted string.
	 389  		if tc.pattern != "" {
	 390  			re, err := Compile(quoted)
	 391  			if err != nil {
	 392  				t.Errorf("Unexpected error compiling QuoteMeta(`%s`): %v", tc.pattern, err)
	 393  				continue
	 394  			}
	 395  			src := "abc" + tc.pattern + "def"
	 396  			repl := "xyz"
	 397  			replaced := re.ReplaceAllString(src, repl)
	 398  			expected := "abcxyzdef"
	 399  			if replaced != expected {
	 400  				t.Errorf("QuoteMeta(`%s`).Replace(`%s`,`%s`) = `%s`; want `%s`",
	 401  					tc.pattern, src, repl, replaced, expected)
	 402  			}
	 403  		}
	 404  	}
	 405  }
	 406  
	 407  func TestLiteralPrefix(t *testing.T) {
	 408  	for _, tc := range append(metaTests, literalPrefixTests...) {
	 409  		// Literal method needs to scan the pattern.
	 410  		re := MustCompile(tc.pattern)
	 411  		str, complete := re.LiteralPrefix()
	 412  		if complete != tc.isLiteral {
	 413  			t.Errorf("LiteralPrefix(`%s`) = %t; want %t", tc.pattern, complete, tc.isLiteral)
	 414  		}
	 415  		if str != tc.literal {
	 416  			t.Errorf("LiteralPrefix(`%s`) = `%s`; want `%s`", tc.pattern, str, tc.literal)
	 417  		}
	 418  	}
	 419  }
	 420  
	 421  type subexpIndex struct {
	 422  	name	string
	 423  	index int
	 424  }
	 425  
	 426  type subexpCase struct {
	 427  	input	 string
	 428  	num		 int
	 429  	names	 []string
	 430  	indices []subexpIndex
	 431  }
	 432  
	 433  var emptySubexpIndices = []subexpIndex{{"", -1}, {"missing", -1}}
	 434  
	 435  var subexpCases = []subexpCase{
	 436  	{``, 0, nil, emptySubexpIndices},
	 437  	{`.*`, 0, nil, emptySubexpIndices},
	 438  	{`abba`, 0, nil, emptySubexpIndices},
	 439  	{`ab(b)a`, 1, []string{"", ""}, emptySubexpIndices},
	 440  	{`ab(.*)a`, 1, []string{"", ""}, emptySubexpIndices},
	 441  	{`(.*)ab(.*)a`, 2, []string{"", "", ""}, emptySubexpIndices},
	 442  	{`(.*)(ab)(.*)a`, 3, []string{"", "", "", ""}, emptySubexpIndices},
	 443  	{`(.*)((a)b)(.*)a`, 4, []string{"", "", "", "", ""}, emptySubexpIndices},
	 444  	{`(.*)(\(ab)(.*)a`, 3, []string{"", "", "", ""}, emptySubexpIndices},
	 445  	{`(.*)(\(a\)b)(.*)a`, 3, []string{"", "", "", ""}, emptySubexpIndices},
	 446  	{`(?P<foo>.*)(?P<bar>(a)b)(?P<foo>.*)a`, 4, []string{"", "foo", "bar", "", "foo"}, []subexpIndex{{"", -1}, {"missing", -1}, {"foo", 1}, {"bar", 2}}},
	 447  }
	 448  
	 449  func TestSubexp(t *testing.T) {
	 450  	for _, c := range subexpCases {
	 451  		re := MustCompile(c.input)
	 452  		n := re.NumSubexp()
	 453  		if n != c.num {
	 454  			t.Errorf("%q: NumSubexp = %d, want %d", c.input, n, c.num)
	 455  			continue
	 456  		}
	 457  		names := re.SubexpNames()
	 458  		if len(names) != 1+n {
	 459  			t.Errorf("%q: len(SubexpNames) = %d, want %d", c.input, len(names), n)
	 460  			continue
	 461  		}
	 462  		if c.names != nil {
	 463  			for i := 0; i < 1+n; i++ {
	 464  				if names[i] != c.names[i] {
	 465  					t.Errorf("%q: SubexpNames[%d] = %q, want %q", c.input, i, names[i], c.names[i])
	 466  				}
	 467  			}
	 468  		}
	 469  		for _, subexp := range c.indices {
	 470  			index := re.SubexpIndex(subexp.name)
	 471  			if index != subexp.index {
	 472  				t.Errorf("%q: SubexpIndex(%q) = %d, want %d", c.input, subexp.name, index, subexp.index)
	 473  			}
	 474  		}
	 475  	}
	 476  }
	 477  
	 478  var splitTests = []struct {
	 479  	s	 string
	 480  	r	 string
	 481  	n	 int
	 482  	out []string
	 483  }{
	 484  	{"foo:and:bar", ":", -1, []string{"foo", "and", "bar"}},
	 485  	{"foo:and:bar", ":", 1, []string{"foo:and:bar"}},
	 486  	{"foo:and:bar", ":", 2, []string{"foo", "and:bar"}},
	 487  	{"foo:and:bar", "foo", -1, []string{"", ":and:bar"}},
	 488  	{"foo:and:bar", "bar", -1, []string{"foo:and:", ""}},
	 489  	{"foo:and:bar", "baz", -1, []string{"foo:and:bar"}},
	 490  	{"baabaab", "a", -1, []string{"b", "", "b", "", "b"}},
	 491  	{"baabaab", "a*", -1, []string{"b", "b", "b"}},
	 492  	{"baabaab", "ba*", -1, []string{"", "", "", ""}},
	 493  	{"foobar", "f*b*", -1, []string{"", "o", "o", "a", "r"}},
	 494  	{"foobar", "f+.*b+", -1, []string{"", "ar"}},
	 495  	{"foobooboar", "o{2}", -1, []string{"f", "b", "boar"}},
	 496  	{"a,b,c,d,e,f", ",", 3, []string{"a", "b", "c,d,e,f"}},
	 497  	{"a,b,c,d,e,f", ",", 0, nil},
	 498  	{",", ",", -1, []string{"", ""}},
	 499  	{",,,", ",", -1, []string{"", "", "", ""}},
	 500  	{"", ",", -1, []string{""}},
	 501  	{"", ".*", -1, []string{""}},
	 502  	{"", ".+", -1, []string{""}},
	 503  	{"", "", -1, []string{}},
	 504  	{"foobar", "", -1, []string{"f", "o", "o", "b", "a", "r"}},
	 505  	{"abaabaccadaaae", "a*", 5, []string{"", "b", "b", "c", "cadaaae"}},
	 506  	{":x:y:z:", ":", -1, []string{"", "x", "y", "z", ""}},
	 507  }
	 508  
	 509  func TestSplit(t *testing.T) {
	 510  	for i, test := range splitTests {
	 511  		re, err := Compile(test.r)
	 512  		if err != nil {
	 513  			t.Errorf("#%d: %q: compile error: %s", i, test.r, err.Error())
	 514  			continue
	 515  		}
	 516  
	 517  		split := re.Split(test.s, test.n)
	 518  		if !reflect.DeepEqual(split, test.out) {
	 519  			t.Errorf("#%d: %q: got %q; want %q", i, test.r, split, test.out)
	 520  		}
	 521  
	 522  		if QuoteMeta(test.r) == test.r {
	 523  			strsplit := strings.SplitN(test.s, test.r, test.n)
	 524  			if !reflect.DeepEqual(split, strsplit) {
	 525  				t.Errorf("#%d: Split(%q, %q, %d): regexp vs strings mismatch\nregexp=%q\nstrings=%q", i, test.s, test.r, test.n, split, strsplit)
	 526  			}
	 527  		}
	 528  	}
	 529  }
	 530  
	 531  // The following sequence of Match calls used to panic. See issue #12980.
	 532  func TestParseAndCompile(t *testing.T) {
	 533  	expr := "a$"
	 534  	s := "a\nb"
	 535  
	 536  	for i, tc := range []struct {
	 537  		reFlags	syntax.Flags
	 538  		expMatch bool
	 539  	}{
	 540  		{syntax.Perl | syntax.OneLine, false},
	 541  		{syntax.Perl &^ syntax.OneLine, true},
	 542  	} {
	 543  		parsed, err := syntax.Parse(expr, tc.reFlags)
	 544  		if err != nil {
	 545  			t.Fatalf("%d: parse: %v", i, err)
	 546  		}
	 547  		re, err := Compile(parsed.String())
	 548  		if err != nil {
	 549  			t.Fatalf("%d: compile: %v", i, err)
	 550  		}
	 551  		if match := re.MatchString(s); match != tc.expMatch {
	 552  			t.Errorf("%d: %q.MatchString(%q)=%t; expected=%t", i, re, s, match, tc.expMatch)
	 553  		}
	 554  	}
	 555  }
	 556  
	 557  // Check that one-pass cutoff does trigger.
	 558  func TestOnePassCutoff(t *testing.T) {
	 559  	re, err := syntax.Parse(`^x{1,1000}y{1,1000}$`, syntax.Perl)
	 560  	if err != nil {
	 561  		t.Fatalf("parse: %v", err)
	 562  	}
	 563  	p, err := syntax.Compile(re.Simplify())
	 564  	if err != nil {
	 565  		t.Fatalf("compile: %v", err)
	 566  	}
	 567  	if compileOnePass(p) != nil {
	 568  		t.Fatalf("makeOnePass succeeded; wanted nil")
	 569  	}
	 570  }
	 571  
	 572  // Check that the same machine can be used with the standard matcher
	 573  // and then the backtracker when there are no captures.
	 574  func TestSwitchBacktrack(t *testing.T) {
	 575  	re := MustCompile(`a|b`)
	 576  	long := make([]byte, maxBacktrackVector+1)
	 577  
	 578  	// The following sequence of Match calls used to panic. See issue #10319.
	 579  	re.Match(long)		 // triggers standard matcher
	 580  	re.Match(long[:1]) // triggers backtracker
	 581  }
	 582  
	 583  func BenchmarkFind(b *testing.B) {
	 584  	b.StopTimer()
	 585  	re := MustCompile("a+b+")
	 586  	wantSubs := "aaabb"
	 587  	s := []byte("acbb" + wantSubs + "dd")
	 588  	b.StartTimer()
	 589  	b.ReportAllocs()
	 590  	for i := 0; i < b.N; i++ {
	 591  		subs := re.Find(s)
	 592  		if string(subs) != wantSubs {
	 593  			b.Fatalf("Find(%q) = %q; want %q", s, subs, wantSubs)
	 594  		}
	 595  	}
	 596  }
	 597  
	 598  func BenchmarkFindAllNoMatches(b *testing.B) {
	 599  	re := MustCompile("a+b+")
	 600  	s := []byte("acddee")
	 601  	b.ReportAllocs()
	 602  	b.ResetTimer()
	 603  	for i := 0; i < b.N; i++ {
	 604  		all := re.FindAll(s, -1)
	 605  		if all != nil {
	 606  			b.Fatalf("FindAll(%q) = %q; want nil", s, all)
	 607  		}
	 608  	}
	 609  }
	 610  
	 611  func BenchmarkFindString(b *testing.B) {
	 612  	b.StopTimer()
	 613  	re := MustCompile("a+b+")
	 614  	wantSubs := "aaabb"
	 615  	s := "acbb" + wantSubs + "dd"
	 616  	b.StartTimer()
	 617  	b.ReportAllocs()
	 618  	for i := 0; i < b.N; i++ {
	 619  		subs := re.FindString(s)
	 620  		if subs != wantSubs {
	 621  			b.Fatalf("FindString(%q) = %q; want %q", s, subs, wantSubs)
	 622  		}
	 623  	}
	 624  }
	 625  
	 626  func BenchmarkFindSubmatch(b *testing.B) {
	 627  	b.StopTimer()
	 628  	re := MustCompile("a(a+b+)b")
	 629  	wantSubs := "aaabb"
	 630  	s := []byte("acbb" + wantSubs + "dd")
	 631  	b.StartTimer()
	 632  	b.ReportAllocs()
	 633  	for i := 0; i < b.N; i++ {
	 634  		subs := re.FindSubmatch(s)
	 635  		if string(subs[0]) != wantSubs {
	 636  			b.Fatalf("FindSubmatch(%q)[0] = %q; want %q", s, subs[0], wantSubs)
	 637  		}
	 638  		if string(subs[1]) != "aab" {
	 639  			b.Fatalf("FindSubmatch(%q)[1] = %q; want %q", s, subs[1], "aab")
	 640  		}
	 641  	}
	 642  }
	 643  
	 644  func BenchmarkFindStringSubmatch(b *testing.B) {
	 645  	b.StopTimer()
	 646  	re := MustCompile("a(a+b+)b")
	 647  	wantSubs := "aaabb"
	 648  	s := "acbb" + wantSubs + "dd"
	 649  	b.StartTimer()
	 650  	b.ReportAllocs()
	 651  	for i := 0; i < b.N; i++ {
	 652  		subs := re.FindStringSubmatch(s)
	 653  		if subs[0] != wantSubs {
	 654  			b.Fatalf("FindStringSubmatch(%q)[0] = %q; want %q", s, subs[0], wantSubs)
	 655  		}
	 656  		if subs[1] != "aab" {
	 657  			b.Fatalf("FindStringSubmatch(%q)[1] = %q; want %q", s, subs[1], "aab")
	 658  		}
	 659  	}
	 660  }
	 661  
	 662  func BenchmarkLiteral(b *testing.B) {
	 663  	x := strings.Repeat("x", 50) + "y"
	 664  	b.StopTimer()
	 665  	re := MustCompile("y")
	 666  	b.StartTimer()
	 667  	for i := 0; i < b.N; i++ {
	 668  		if !re.MatchString(x) {
	 669  			b.Fatalf("no match!")
	 670  		}
	 671  	}
	 672  }
	 673  
	 674  func BenchmarkNotLiteral(b *testing.B) {
	 675  	x := strings.Repeat("x", 50) + "y"
	 676  	b.StopTimer()
	 677  	re := MustCompile(".y")
	 678  	b.StartTimer()
	 679  	for i := 0; i < b.N; i++ {
	 680  		if !re.MatchString(x) {
	 681  			b.Fatalf("no match!")
	 682  		}
	 683  	}
	 684  }
	 685  
	 686  func BenchmarkMatchClass(b *testing.B) {
	 687  	b.StopTimer()
	 688  	x := strings.Repeat("xxxx", 20) + "w"
	 689  	re := MustCompile("[abcdw]")
	 690  	b.StartTimer()
	 691  	for i := 0; i < b.N; i++ {
	 692  		if !re.MatchString(x) {
	 693  			b.Fatalf("no match!")
	 694  		}
	 695  	}
	 696  }
	 697  
	 698  func BenchmarkMatchClass_InRange(b *testing.B) {
	 699  	b.StopTimer()
	 700  	// 'b' is between 'a' and 'c', so the charclass
	 701  	// range checking is no help here.
	 702  	x := strings.Repeat("bbbb", 20) + "c"
	 703  	re := MustCompile("[ac]")
	 704  	b.StartTimer()
	 705  	for i := 0; i < b.N; i++ {
	 706  		if !re.MatchString(x) {
	 707  			b.Fatalf("no match!")
	 708  		}
	 709  	}
	 710  }
	 711  
	 712  func BenchmarkReplaceAll(b *testing.B) {
	 713  	x := "abcdefghijklmnopqrstuvwxyz"
	 714  	b.StopTimer()
	 715  	re := MustCompile("[cjrw]")
	 716  	b.StartTimer()
	 717  	for i := 0; i < b.N; i++ {
	 718  		re.ReplaceAllString(x, "")
	 719  	}
	 720  }
	 721  
	 722  func BenchmarkAnchoredLiteralShortNonMatch(b *testing.B) {
	 723  	b.StopTimer()
	 724  	x := []byte("abcdefghijklmnopqrstuvwxyz")
	 725  	re := MustCompile("^zbc(d|e)")
	 726  	b.StartTimer()
	 727  	for i := 0; i < b.N; i++ {
	 728  		re.Match(x)
	 729  	}
	 730  }
	 731  
	 732  func BenchmarkAnchoredLiteralLongNonMatch(b *testing.B) {
	 733  	b.StopTimer()
	 734  	x := []byte("abcdefghijklmnopqrstuvwxyz")
	 735  	for i := 0; i < 15; i++ {
	 736  		x = append(x, x...)
	 737  	}
	 738  	re := MustCompile("^zbc(d|e)")
	 739  	b.StartTimer()
	 740  	for i := 0; i < b.N; i++ {
	 741  		re.Match(x)
	 742  	}
	 743  }
	 744  
	 745  func BenchmarkAnchoredShortMatch(b *testing.B) {
	 746  	b.StopTimer()
	 747  	x := []byte("abcdefghijklmnopqrstuvwxyz")
	 748  	re := MustCompile("^.bc(d|e)")
	 749  	b.StartTimer()
	 750  	for i := 0; i < b.N; i++ {
	 751  		re.Match(x)
	 752  	}
	 753  }
	 754  
	 755  func BenchmarkAnchoredLongMatch(b *testing.B) {
	 756  	b.StopTimer()
	 757  	x := []byte("abcdefghijklmnopqrstuvwxyz")
	 758  	for i := 0; i < 15; i++ {
	 759  		x = append(x, x...)
	 760  	}
	 761  	re := MustCompile("^.bc(d|e)")
	 762  	b.StartTimer()
	 763  	for i := 0; i < b.N; i++ {
	 764  		re.Match(x)
	 765  	}
	 766  }
	 767  
	 768  func BenchmarkOnePassShortA(b *testing.B) {
	 769  	b.StopTimer()
	 770  	x := []byte("abcddddddeeeededd")
	 771  	re := MustCompile("^.bc(d|e)*$")
	 772  	b.StartTimer()
	 773  	for i := 0; i < b.N; i++ {
	 774  		re.Match(x)
	 775  	}
	 776  }
	 777  
	 778  func BenchmarkNotOnePassShortA(b *testing.B) {
	 779  	b.StopTimer()
	 780  	x := []byte("abcddddddeeeededd")
	 781  	re := MustCompile(".bc(d|e)*$")
	 782  	b.StartTimer()
	 783  	for i := 0; i < b.N; i++ {
	 784  		re.Match(x)
	 785  	}
	 786  }
	 787  
	 788  func BenchmarkOnePassShortB(b *testing.B) {
	 789  	b.StopTimer()
	 790  	x := []byte("abcddddddeeeededd")
	 791  	re := MustCompile("^.bc(?:d|e)*$")
	 792  	b.StartTimer()
	 793  	for i := 0; i < b.N; i++ {
	 794  		re.Match(x)
	 795  	}
	 796  }
	 797  
	 798  func BenchmarkNotOnePassShortB(b *testing.B) {
	 799  	b.StopTimer()
	 800  	x := []byte("abcddddddeeeededd")
	 801  	re := MustCompile(".bc(?:d|e)*$")
	 802  	b.StartTimer()
	 803  	for i := 0; i < b.N; i++ {
	 804  		re.Match(x)
	 805  	}
	 806  }
	 807  
	 808  func BenchmarkOnePassLongPrefix(b *testing.B) {
	 809  	b.StopTimer()
	 810  	x := []byte("abcdefghijklmnopqrstuvwxyz")
	 811  	re := MustCompile("^abcdefghijklmnopqrstuvwxyz.*$")
	 812  	b.StartTimer()
	 813  	for i := 0; i < b.N; i++ {
	 814  		re.Match(x)
	 815  	}
	 816  }
	 817  
	 818  func BenchmarkOnePassLongNotPrefix(b *testing.B) {
	 819  	b.StopTimer()
	 820  	x := []byte("abcdefghijklmnopqrstuvwxyz")
	 821  	re := MustCompile("^.bcdefghijklmnopqrstuvwxyz.*$")
	 822  	b.StartTimer()
	 823  	for i := 0; i < b.N; i++ {
	 824  		re.Match(x)
	 825  	}
	 826  }
	 827  
	 828  func BenchmarkMatchParallelShared(b *testing.B) {
	 829  	x := []byte("this is a long line that contains foo bar baz")
	 830  	re := MustCompile("foo (ba+r)? baz")
	 831  	b.ResetTimer()
	 832  	b.RunParallel(func(pb *testing.PB) {
	 833  		for pb.Next() {
	 834  			re.Match(x)
	 835  		}
	 836  	})
	 837  }
	 838  
	 839  func BenchmarkMatchParallelCopied(b *testing.B) {
	 840  	x := []byte("this is a long line that contains foo bar baz")
	 841  	re := MustCompile("foo (ba+r)? baz")
	 842  	b.ResetTimer()
	 843  	b.RunParallel(func(pb *testing.PB) {
	 844  		re := re.Copy()
	 845  		for pb.Next() {
	 846  			re.Match(x)
	 847  		}
	 848  	})
	 849  }
	 850  
	 851  var sink string
	 852  
	 853  func BenchmarkQuoteMetaAll(b *testing.B) {
	 854  	specials := make([]byte, 0)
	 855  	for i := byte(0); i < utf8.RuneSelf; i++ {
	 856  		if special(i) {
	 857  			specials = append(specials, i)
	 858  		}
	 859  	}
	 860  	s := string(specials)
	 861  	b.SetBytes(int64(len(s)))
	 862  	b.ResetTimer()
	 863  	for i := 0; i < b.N; i++ {
	 864  		sink = QuoteMeta(s)
	 865  	}
	 866  }
	 867  
	 868  func BenchmarkQuoteMetaNone(b *testing.B) {
	 869  	s := "abcdefghijklmnopqrstuvwxyz"
	 870  	b.SetBytes(int64(len(s)))
	 871  	b.ResetTimer()
	 872  	for i := 0; i < b.N; i++ {
	 873  		sink = QuoteMeta(s)
	 874  	}
	 875  }
	 876  
	 877  var compileBenchData = []struct{ name, re string }{
	 878  	{"Onepass", `^a.[l-nA-Cg-j]?e$`},
	 879  	{"Medium", `^((a|b|[d-z0-9])*(日){4,5}.)+$`},
	 880  	{"Hard", strings.Repeat(`((abc)*|`, 50) + strings.Repeat(`)`, 50)},
	 881  }
	 882  
	 883  func BenchmarkCompile(b *testing.B) {
	 884  	for _, data := range compileBenchData {
	 885  		b.Run(data.name, func(b *testing.B) {
	 886  			b.ReportAllocs()
	 887  			for i := 0; i < b.N; i++ {
	 888  				if _, err := Compile(data.re); err != nil {
	 889  					b.Fatal(err)
	 890  				}
	 891  			}
	 892  		})
	 893  	}
	 894  }
	 895  
	 896  func TestDeepEqual(t *testing.T) {
	 897  	re1 := MustCompile("a.*b.*c.*d")
	 898  	re2 := MustCompile("a.*b.*c.*d")
	 899  	if !reflect.DeepEqual(re1, re2) { // has always been true, since Go 1.
	 900  		t.Errorf("DeepEqual(re1, re2) = false, want true")
	 901  	}
	 902  
	 903  	re1.MatchString("abcdefghijklmn")
	 904  	if !reflect.DeepEqual(re1, re2) {
	 905  		t.Errorf("DeepEqual(re1, re2) = false, want true")
	 906  	}
	 907  
	 908  	re2.MatchString("abcdefghijklmn")
	 909  	if !reflect.DeepEqual(re1, re2) {
	 910  		t.Errorf("DeepEqual(re1, re2) = false, want true")
	 911  	}
	 912  
	 913  	re2.MatchString(strings.Repeat("abcdefghijklmn", 100))
	 914  	if !reflect.DeepEqual(re1, re2) {
	 915  		t.Errorf("DeepEqual(re1, re2) = false, want true")
	 916  	}
	 917  }
	 918  
	 919  var minInputLenTests = []struct {
	 920  	Regexp string
	 921  	min		int
	 922  }{
	 923  	{``, 0},
	 924  	{`a`, 1},
	 925  	{`aa`, 2},
	 926  	{`(aa)a`, 3},
	 927  	{`(?:aa)a`, 3},
	 928  	{`a?a`, 1},
	 929  	{`(aaa)|(aa)`, 2},
	 930  	{`(aa)+a`, 3},
	 931  	{`(aa)*a`, 1},
	 932  	{`(aa){3,5}`, 6},
	 933  	{`[a-z]`, 1},
	 934  	{`日`, 3},
	 935  }
	 936  
	 937  func TestMinInputLen(t *testing.T) {
	 938  	for _, tt := range minInputLenTests {
	 939  		re, _ := syntax.Parse(tt.Regexp, syntax.Perl)
	 940  		m := minInputLen(re)
	 941  		if m != tt.min {
	 942  			t.Errorf("regexp %#q has minInputLen %d, should be %d", tt.Regexp, m, tt.min)
	 943  		}
	 944  	}
	 945  }
	 946  

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