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      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 	{`+`, `\+`, ``, 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 subexpCase struct {
    422 	input string
    423 	num   int
    424 	names []string
    425 }
    426 
    427 var subexpCases = []subexpCase{
    428 	{``, 0, nil},
    429 	{`.*`, 0, nil},
    430 	{`abba`, 0, nil},
    431 	{`ab(b)a`, 1, []string{"", ""}},
    432 	{`ab(.*)a`, 1, []string{"", ""}},
    433 	{`(.*)ab(.*)a`, 2, []string{"", "", ""}},
    434 	{`(.*)(ab)(.*)a`, 3, []string{"", "", "", ""}},
    435 	{`(.*)((a)b)(.*)a`, 4, []string{"", "", "", "", ""}},
    436 	{`(.*)(\(ab)(.*)a`, 3, []string{"", "", "", ""}},
    437 	{`(.*)(\(a\)b)(.*)a`, 3, []string{"", "", "", ""}},
    438 	{`(?P<foo>.*)(?P<bar>(a)b)(?P<foo>.*)a`, 4, []string{"", "foo", "bar", "", "foo"}},
    439 }
    440 
    441 func TestSubexp(t *testing.T) {
    442 	for _, c := range subexpCases {
    443 		re := MustCompile(c.input)
    444 		n := re.NumSubexp()
    445 		if n != c.num {
    446 			t.Errorf("%q: NumSubexp = %d, want %d", c.input, n, c.num)
    447 			continue
    448 		}
    449 		names := re.SubexpNames()
    450 		if len(names) != 1+n {
    451 			t.Errorf("%q: len(SubexpNames) = %d, want %d", c.input, len(names), n)
    452 			continue
    453 		}
    454 		if c.names != nil {
    455 			for i := 0; i < 1+n; i++ {
    456 				if names[i] != c.names[i] {
    457 					t.Errorf("%q: SubexpNames[%d] = %q, want %q", c.input, i, names[i], c.names[i])
    458 				}
    459 			}
    460 		}
    461 	}
    462 }
    463 
    464 var splitTests = []struct {
    465 	s   string
    466 	r   string
    467 	n   int
    468 	out []string
    469 }{
    470 	{"foo:and:bar", ":", -1, []string{"foo", "and", "bar"}},
    471 	{"foo:and:bar", ":", 1, []string{"foo:and:bar"}},
    472 	{"foo:and:bar", ":", 2, []string{"foo", "and:bar"}},
    473 	{"foo:and:bar", "foo", -1, []string{"", ":and:bar"}},
    474 	{"foo:and:bar", "bar", -1, []string{"foo:and:", ""}},
    475 	{"foo:and:bar", "baz", -1, []string{"foo:and:bar"}},
    476 	{"baabaab", "a", -1, []string{"b", "", "b", "", "b"}},
    477 	{"baabaab", "a*", -1, []string{"b", "b", "b"}},
    478 	{"baabaab", "ba*", -1, []string{"", "", "", ""}},
    479 	{"foobar", "f*b*", -1, []string{"", "o", "o", "a", "r"}},
    480 	{"foobar", "f+.*b+", -1, []string{"", "ar"}},
    481 	{"foobooboar", "o{2}", -1, []string{"f", "b", "boar"}},
    482 	{"a,b,c,d,e,f", ",", 3, []string{"a", "b", "c,d,e,f"}},
    483 	{"a,b,c,d,e,f", ",", 0, nil},
    484 	{",", ",", -1, []string{"", ""}},
    485 	{",,,", ",", -1, []string{"", "", "", ""}},
    486 	{"", ",", -1, []string{""}},
    487 	{"", ".*", -1, []string{""}},
    488 	{"", ".+", -1, []string{""}},
    489 	{"", "", -1, []string{}},
    490 	{"foobar", "", -1, []string{"f", "o", "o", "b", "a", "r"}},
    491 	{"abaabaccadaaae", "a*", 5, []string{"", "b", "b", "c", "cadaaae"}},
    492 	{":x:y:z:", ":", -1, []string{"", "x", "y", "z", ""}},
    493 }
    494 
    495 func TestSplit(t *testing.T) {
    496 	for i, test := range splitTests {
    497 		re, err := Compile(test.r)
    498 		if err != nil {
    499 			t.Errorf("#%d: %q: compile error: %s", i, test.r, err.Error())
    500 			continue
    501 		}
    502 
    503 		split := re.Split(test.s, test.n)
    504 		if !reflect.DeepEqual(split, test.out) {
    505 			t.Errorf("#%d: %q: got %q; want %q", i, test.r, split, test.out)
    506 		}
    507 
    508 		if QuoteMeta(test.r) == test.r {
    509 			strsplit := strings.SplitN(test.s, test.r, test.n)
    510 			if !reflect.DeepEqual(split, strsplit) {
    511 				t.Errorf("#%d: Split(%q, %q, %d): regexp vs strings mismatch\nregexp=%q\nstrings=%q", i, test.s, test.r, test.n, split, strsplit)
    512 			}
    513 		}
    514 	}
    515 }
    516 
    517 // The following sequence of Match calls used to panic. See issue #12980.
    518 func TestParseAndCompile(t *testing.T) {
    519 	expr := "a$"
    520 	s := "a\nb"
    521 
    522 	for i, tc := range []struct {
    523 		reFlags  syntax.Flags
    524 		expMatch bool
    525 	}{
    526 		{syntax.Perl | syntax.OneLine, false},
    527 		{syntax.Perl &^ syntax.OneLine, true},
    528 	} {
    529 		parsed, err := syntax.Parse(expr, tc.reFlags)
    530 		if err != nil {
    531 			t.Fatalf("%d: parse: %v", i, err)
    532 		}
    533 		re, err := Compile(parsed.String())
    534 		if err != nil {
    535 			t.Fatalf("%d: compile: %v", i, err)
    536 		}
    537 		if match := re.MatchString(s); match != tc.expMatch {
    538 			t.Errorf("%d: %q.MatchString(%q)=%t; expected=%t", i, re, s, match, tc.expMatch)
    539 		}
    540 	}
    541 }
    542 
    543 // Check that one-pass cutoff does trigger.
    544 func TestOnePassCutoff(t *testing.T) {
    545 	re, err := syntax.Parse(`^x{1,1000}y{1,1000}$`, syntax.Perl)
    546 	if err != nil {
    547 		t.Fatalf("parse: %v", err)
    548 	}
    549 	p, err := syntax.Compile(re.Simplify())
    550 	if err != nil {
    551 		t.Fatalf("compile: %v", err)
    552 	}
    553 	if compileOnePass(p) != notOnePass {
    554 		t.Fatalf("makeOnePass succeeded; wanted notOnePass")
    555 	}
    556 }
    557 
    558 // Check that the same machine can be used with the standard matcher
    559 // and then the backtracker when there are no captures.
    560 func TestSwitchBacktrack(t *testing.T) {
    561 	re := MustCompile(`a|b`)
    562 	long := make([]byte, maxBacktrackVector+1)
    563 
    564 	// The following sequence of Match calls used to panic. See issue #10319.
    565 	re.Match(long)     // triggers standard matcher
    566 	re.Match(long[:1]) // triggers backtracker
    567 }
    568 
    569 func BenchmarkFind(b *testing.B) {
    570 	b.StopTimer()
    571 	re := MustCompile("a+b+")
    572 	wantSubs := "aaabb"
    573 	s := []byte("acbb" + wantSubs + "dd")
    574 	b.StartTimer()
    575 	b.ReportAllocs()
    576 	for i := 0; i < b.N; i++ {
    577 		subs := re.Find(s)
    578 		if string(subs) != wantSubs {
    579 			b.Fatalf("Find(%q) = %q; want %q", s, subs, wantSubs)
    580 		}
    581 	}
    582 }
    583 
    584 func BenchmarkFindString(b *testing.B) {
    585 	b.StopTimer()
    586 	re := MustCompile("a+b+")
    587 	wantSubs := "aaabb"
    588 	s := "acbb" + wantSubs + "dd"
    589 	b.StartTimer()
    590 	b.ReportAllocs()
    591 	for i := 0; i < b.N; i++ {
    592 		subs := re.FindString(s)
    593 		if subs != wantSubs {
    594 			b.Fatalf("FindString(%q) = %q; want %q", s, subs, wantSubs)
    595 		}
    596 	}
    597 }
    598 
    599 func BenchmarkFindSubmatch(b *testing.B) {
    600 	b.StopTimer()
    601 	re := MustCompile("a(a+b+)b")
    602 	wantSubs := "aaabb"
    603 	s := []byte("acbb" + wantSubs + "dd")
    604 	b.StartTimer()
    605 	b.ReportAllocs()
    606 	for i := 0; i < b.N; i++ {
    607 		subs := re.FindSubmatch(s)
    608 		if string(subs[0]) != wantSubs {
    609 			b.Fatalf("FindSubmatch(%q)[0] = %q; want %q", s, subs[0], wantSubs)
    610 		}
    611 		if string(subs[1]) != "aab" {
    612 			b.Fatalf("FindSubmatch(%q)[1] = %q; want %q", s, subs[1], "aab")
    613 		}
    614 	}
    615 }
    616 
    617 func BenchmarkFindStringSubmatch(b *testing.B) {
    618 	b.StopTimer()
    619 	re := MustCompile("a(a+b+)b")
    620 	wantSubs := "aaabb"
    621 	s := "acbb" + wantSubs + "dd"
    622 	b.StartTimer()
    623 	b.ReportAllocs()
    624 	for i := 0; i < b.N; i++ {
    625 		subs := re.FindStringSubmatch(s)
    626 		if subs[0] != wantSubs {
    627 			b.Fatalf("FindStringSubmatch(%q)[0] = %q; want %q", s, subs[0], wantSubs)
    628 		}
    629 		if subs[1] != "aab" {
    630 			b.Fatalf("FindStringSubmatch(%q)[1] = %q; want %q", s, subs[1], "aab")
    631 		}
    632 	}
    633 }
    634 
    635 func BenchmarkLiteral(b *testing.B) {
    636 	x := strings.Repeat("x", 50) + "y"
    637 	b.StopTimer()
    638 	re := MustCompile("y")
    639 	b.StartTimer()
    640 	for i := 0; i < b.N; i++ {
    641 		if !re.MatchString(x) {
    642 			b.Fatalf("no match!")
    643 		}
    644 	}
    645 }
    646 
    647 func BenchmarkNotLiteral(b *testing.B) {
    648 	x := strings.Repeat("x", 50) + "y"
    649 	b.StopTimer()
    650 	re := MustCompile(".y")
    651 	b.StartTimer()
    652 	for i := 0; i < b.N; i++ {
    653 		if !re.MatchString(x) {
    654 			b.Fatalf("no match!")
    655 		}
    656 	}
    657 }
    658 
    659 func BenchmarkMatchClass(b *testing.B) {
    660 	b.StopTimer()
    661 	x := strings.Repeat("xxxx", 20) + "w"
    662 	re := MustCompile("[abcdw]")
    663 	b.StartTimer()
    664 	for i := 0; i < b.N; i++ {
    665 		if !re.MatchString(x) {
    666 			b.Fatalf("no match!")
    667 		}
    668 	}
    669 }
    670 
    671 func BenchmarkMatchClass_InRange(b *testing.B) {
    672 	b.StopTimer()
    673 	// 'b' is between 'a' and 'c', so the charclass
    674 	// range checking is no help here.
    675 	x := strings.Repeat("bbbb", 20) + "c"
    676 	re := MustCompile("[ac]")
    677 	b.StartTimer()
    678 	for i := 0; i < b.N; i++ {
    679 		if !re.MatchString(x) {
    680 			b.Fatalf("no match!")
    681 		}
    682 	}
    683 }
    684 
    685 func BenchmarkReplaceAll(b *testing.B) {
    686 	x := "abcdefghijklmnopqrstuvwxyz"
    687 	b.StopTimer()
    688 	re := MustCompile("[cjrw]")
    689 	b.StartTimer()
    690 	for i := 0; i < b.N; i++ {
    691 		re.ReplaceAllString(x, "")
    692 	}
    693 }
    694 
    695 func BenchmarkAnchoredLiteralShortNonMatch(b *testing.B) {
    696 	b.StopTimer()
    697 	x := []byte("abcdefghijklmnopqrstuvwxyz")
    698 	re := MustCompile("^zbc(d|e)")
    699 	b.StartTimer()
    700 	for i := 0; i < b.N; i++ {
    701 		re.Match(x)
    702 	}
    703 }
    704 
    705 func BenchmarkAnchoredLiteralLongNonMatch(b *testing.B) {
    706 	b.StopTimer()
    707 	x := []byte("abcdefghijklmnopqrstuvwxyz")
    708 	for i := 0; i < 15; i++ {
    709 		x = append(x, x...)
    710 	}
    711 	re := MustCompile("^zbc(d|e)")
    712 	b.StartTimer()
    713 	for i := 0; i < b.N; i++ {
    714 		re.Match(x)
    715 	}
    716 }
    717 
    718 func BenchmarkAnchoredShortMatch(b *testing.B) {
    719 	b.StopTimer()
    720 	x := []byte("abcdefghijklmnopqrstuvwxyz")
    721 	re := MustCompile("^.bc(d|e)")
    722 	b.StartTimer()
    723 	for i := 0; i < b.N; i++ {
    724 		re.Match(x)
    725 	}
    726 }
    727 
    728 func BenchmarkAnchoredLongMatch(b *testing.B) {
    729 	b.StopTimer()
    730 	x := []byte("abcdefghijklmnopqrstuvwxyz")
    731 	for i := 0; i < 15; i++ {
    732 		x = append(x, x...)
    733 	}
    734 	re := MustCompile("^.bc(d|e)")
    735 	b.StartTimer()
    736 	for i := 0; i < b.N; i++ {
    737 		re.Match(x)
    738 	}
    739 }
    740 
    741 func BenchmarkOnePassShortA(b *testing.B) {
    742 	b.StopTimer()
    743 	x := []byte("abcddddddeeeededd")
    744 	re := MustCompile("^.bc(d|e)*$")
    745 	b.StartTimer()
    746 	for i := 0; i < b.N; i++ {
    747 		re.Match(x)
    748 	}
    749 }
    750 
    751 func BenchmarkNotOnePassShortA(b *testing.B) {
    752 	b.StopTimer()
    753 	x := []byte("abcddddddeeeededd")
    754 	re := MustCompile(".bc(d|e)*$")
    755 	b.StartTimer()
    756 	for i := 0; i < b.N; i++ {
    757 		re.Match(x)
    758 	}
    759 }
    760 
    761 func BenchmarkOnePassShortB(b *testing.B) {
    762 	b.StopTimer()
    763 	x := []byte("abcddddddeeeededd")
    764 	re := MustCompile("^.bc(?:d|e)*$")
    765 	b.StartTimer()
    766 	for i := 0; i < b.N; i++ {
    767 		re.Match(x)
    768 	}
    769 }
    770 
    771 func BenchmarkNotOnePassShortB(b *testing.B) {
    772 	b.StopTimer()
    773 	x := []byte("abcddddddeeeededd")
    774 	re := MustCompile(".bc(?:d|e)*$")
    775 	b.StartTimer()
    776 	for i := 0; i < b.N; i++ {
    777 		re.Match(x)
    778 	}
    779 }
    780 
    781 func BenchmarkOnePassLongPrefix(b *testing.B) {
    782 	b.StopTimer()
    783 	x := []byte("abcdefghijklmnopqrstuvwxyz")
    784 	re := MustCompile("^abcdefghijklmnopqrstuvwxyz.*$")
    785 	b.StartTimer()
    786 	for i := 0; i < b.N; i++ {
    787 		re.Match(x)
    788 	}
    789 }
    790 
    791 func BenchmarkOnePassLongNotPrefix(b *testing.B) {
    792 	b.StopTimer()
    793 	x := []byte("abcdefghijklmnopqrstuvwxyz")
    794 	re := MustCompile("^.bcdefghijklmnopqrstuvwxyz.*$")
    795 	b.StartTimer()
    796 	for i := 0; i < b.N; i++ {
    797 		re.Match(x)
    798 	}
    799 }
    800 
    801 func BenchmarkMatchParallelShared(b *testing.B) {
    802 	x := []byte("this is a long line that contains foo bar baz")
    803 	re := MustCompile("foo (ba+r)? baz")
    804 	b.ResetTimer()
    805 	b.RunParallel(func(pb *testing.PB) {
    806 		for pb.Next() {
    807 			re.Match(x)
    808 		}
    809 	})
    810 }
    811 
    812 func BenchmarkMatchParallelCopied(b *testing.B) {
    813 	x := []byte("this is a long line that contains foo bar baz")
    814 	re := MustCompile("foo (ba+r)? baz")
    815 	b.ResetTimer()
    816 	b.RunParallel(func(pb *testing.PB) {
    817 		re := re.Copy()
    818 		for pb.Next() {
    819 			re.Match(x)
    820 		}
    821 	})
    822 }
    823 
    824 var sink string
    825 
    826 func BenchmarkQuoteMetaAll(b *testing.B) {
    827 	specials := make([]byte, 0)
    828 	for i := byte(0); i < utf8.RuneSelf; i++ {
    829 		if special(i) {
    830 			specials = append(specials, i)
    831 		}
    832 	}
    833 	s := string(specials)
    834 	b.SetBytes(int64(len(s)))
    835 	b.ResetTimer()
    836 	for i := 0; i < b.N; i++ {
    837 		sink = QuoteMeta(s)
    838 	}
    839 }
    840 
    841 func BenchmarkQuoteMetaNone(b *testing.B) {
    842 	s := "abcdefghijklmnopqrstuvwxyz"
    843 	b.SetBytes(int64(len(s)))
    844 	b.ResetTimer()
    845 	for i := 0; i < b.N; i++ {
    846 		sink = QuoteMeta(s)
    847 	}
    848 }
    849