From 07b5f6f5d81e3fd11ed37c9e4067d6c279877771 Mon Sep 17 00:00:00 2001 From: Bhavitha <106284071+bhavi-koduru@users.noreply.github.com> Date: Thu, 13 Apr 2023 08:57:57 -0700 Subject: [PATCH] add Cut method to bytes package --- api/go1.15.txt | 1 + src/bytes/bytes.go | 13 ++++ src/bytes/bytes_test.go | 23 +++++++ src/bytes/example_test.go | 138 +++++++++++++++++++------------------- 4 files changed, 107 insertions(+), 68 deletions(-) diff --git a/api/go1.15.txt b/api/go1.15.txt index dd90506eba..6ba3a7892f 100644 --- a/api/go1.15.txt +++ b/api/go1.15.txt @@ -1,4 +1,5 @@ pkg bufio, var ErrBadReadCount error +pkg bytes, func Cut([]uint8, []uint8) ([]uint8, []uint8, bool) pkg crypto, method (Hash) String() string pkg crypto/ecdsa, func SignASN1(io.Reader, *PrivateKey, []uint8) ([]uint8, error) pkg crypto/ecdsa, func VerifyASN1(*PublicKey, []uint8, []uint8) bool diff --git a/src/bytes/bytes.go b/src/bytes/bytes.go index ce52649f13..ec9a2eb693 100644 --- a/src/bytes/bytes.go +++ b/src/bytes/bytes.go @@ -1174,3 +1174,16 @@ func Index(s, sep []byte) int { } return -1 } + +// Cut slices s around the first instance of sep, +// returning the text before and after sep. +// The found result reports whether sep appears in s. +// If sep does not appear in s, cut returns s, "", false. +// +// Cut returns slices of the original slice s, not copies. +func Cut(s, sep []byte) (before, after []byte, found bool) { + if i := Index(s, sep); i >= 0 { + return s[:i], s[i+len(sep):], true + } + return s, nil, false +} diff --git a/src/bytes/bytes_test.go b/src/bytes/bytes_test.go index 544ee46f90..538e613c8e 100644 --- a/src/bytes/bytes_test.go +++ b/src/bytes/bytes_test.go @@ -1565,6 +1565,29 @@ func TestEqualFold(t *testing.T) { } } +var cutTests = []struct { + s, sep string + before, after string + found bool +}{ + {"abc", "b", "a", "c", true}, + {"abc", "a", "", "bc", true}, + {"abc", "c", "ab", "", true}, + {"abc", "abc", "", "", true}, + {"abc", "", "", "abc", true}, + {"abc", "d", "abc", "", false}, + {"", "d", "", "", false}, + {"", "", "", "", true}, +} + +func TestCut(t *testing.T) { + for _, tt := range cutTests { + if before, after, found := Cut([]byte(tt.s), []byte(tt.sep)); string(before) != tt.before || string(after) != tt.after || found != tt.found { + t.Errorf("Cut(%q, %q) = %q, %q, %v, want %q, %q, %v", tt.s, tt.sep, before, after, found, tt.before, tt.after, tt.found) + } + } +} + func TestBufferGrowNegative(t *testing.T) { defer func() { if err := recover(); err == nil { diff --git a/src/bytes/example_test.go b/src/bytes/example_test.go index 5ba7077c1d..554f7303c8 100644 --- a/src/bytes/example_test.go +++ b/src/bytes/example_test.go @@ -85,36 +85,6 @@ func ExampleCompare_search() { } } -func ExampleTrimSuffix() { - var b = []byte("Hello, goodbye, etc!") - b = bytes.TrimSuffix(b, []byte("goodbye, etc!")) - b = bytes.TrimSuffix(b, []byte("gopher")) - b = append(b, bytes.TrimSuffix([]byte("world!"), []byte("x!"))...) - os.Stdout.Write(b) - // Output: Hello, world! -} - -func ExampleTrimPrefix() { - var b = []byte("Goodbye,, world!") - b = bytes.TrimPrefix(b, []byte("Goodbye,")) - b = bytes.TrimPrefix(b, []byte("See ya,")) - fmt.Printf("Hello%s", b) - // Output: Hello, world! -} - -func ExampleFields() { - fmt.Printf("Fields are: %q", bytes.Fields([]byte(" foo bar baz "))) - // Output: Fields are: ["foo" "bar" "baz"] -} - -func ExampleFieldsFunc() { - f := func(c rune) bool { - return !unicode.IsLetter(c) && !unicode.IsNumber(c) - } - fmt.Printf("Fields are: %q", bytes.FieldsFunc([]byte(" foo1;bar2,baz3..."), f)) - // Output: Fields are: ["foo1" "bar2" "baz3"] -} - func ExampleContains() { fmt.Println(bytes.Contains([]byte("seafood"), []byte("foo"))) fmt.Println(bytes.Contains([]byte("seafood"), []byte("bar"))) @@ -161,6 +131,22 @@ func ExampleCount() { // 5 } +func ExampleCut() { + show := func(s, sep string) { + before, after, found := bytes.Cut([]byte(s), []byte(sep)) + fmt.Printf("Cut(%q, %q) = %q, %q, %v\n", s, sep, before, after, found) + } + show("Gopher", "Go") + show("Gopher", "ph") + show("Gopher", "er") + show("Gopher", "Badger") + // Output: + // Cut("Gopher", "Go") = "", "pher", true + // Cut("Gopher", "ph") = "Go", "er", true + // Cut("Gopher", "er") = "Goph", "", true + // Cut("Gopher", "Badger") = "Gopher", "", false +} + func ExampleEqual() { fmt.Println(bytes.Equal([]byte("Go"), []byte("Go"))) fmt.Println(bytes.Equal([]byte("Go"), []byte("C++"))) @@ -174,6 +160,19 @@ func ExampleEqualFold() { // Output: true } +func ExampleFields() { + fmt.Printf("Fields are: %q", bytes.Fields([]byte(" foo bar baz "))) + // Output: Fields are: ["foo" "bar" "baz"] +} + +func ExampleFieldsFunc() { + f := func(c rune) bool { + return !unicode.IsLetter(c) && !unicode.IsNumber(c) + } + fmt.Printf("Fields are: %q", bytes.FieldsFunc([]byte(" foo1;bar2,baz3..."), f)) + // Output: Fields are: ["foo1" "bar2" "baz3"] +} + func ExampleHasPrefix() { fmt.Println(bytes.HasPrefix([]byte("Gopher"), []byte("Go"))) fmt.Println(bytes.HasPrefix([]byte("Gopher"), []byte("C"))) @@ -239,6 +238,12 @@ func ExampleIndexRune() { // -1 } +func ExampleJoin() { + s := [][]byte{[]byte("foo"), []byte("bar"), []byte("baz")} + fmt.Printf("%s", bytes.Join(s, []byte(", "))) + // Output: foo, bar, baz +} + func ExampleLastIndex() { fmt.Println(bytes.Index([]byte("go gopher"), []byte("go"))) fmt.Println(bytes.LastIndex([]byte("go gopher"), []byte("go"))) @@ -279,10 +284,12 @@ func ExampleLastIndexFunc() { // -1 } -func ExampleJoin() { - s := [][]byte{[]byte("foo"), []byte("bar"), []byte("baz")} - fmt.Printf("%s", bytes.Join(s, []byte(", "))) - // Output: foo, bar, baz +func ExampleReader_Len() { + fmt.Println(bytes.NewReader([]byte("Hi!")).Len()) + fmt.Println(bytes.NewReader([]byte("こんにちは!")).Len()) + // Output: + // 3 + // 16 } func ExampleRepeat() { @@ -392,20 +399,6 @@ func ExampleTrimFunc() { // go-gopher! } -func ExampleMap() { - rot13 := func(r rune) rune { - switch { - case r >= 'A' && r <= 'Z': - return 'A' + (r-'A'+13)%26 - case r >= 'a' && r <= 'z': - return 'a' + (r-'a'+13)%26 - } - return r - } - fmt.Printf("%s", bytes.Map(rot13, []byte("'Twas brillig and the slithy gopher..."))) - // Output: 'Gjnf oevyyvt naq gur fyvgul tbcure... -} - func ExampleTrimLeft() { fmt.Print(string(bytes.TrimLeft([]byte("453gopher8257"), "0123456789"))) // Output: @@ -422,11 +415,28 @@ func ExampleTrimLeftFunc() { // go-gopher!567 } +func ExampleTrimPrefix() { + var b = []byte("Goodbye,, world!") + b = bytes.TrimPrefix(b, []byte("Goodbye,")) + b = bytes.TrimPrefix(b, []byte("See ya,")) + fmt.Printf("Hello%s", b) + // Output: Hello, world! +} + func ExampleTrimSpace() { fmt.Printf("%s", bytes.TrimSpace([]byte(" \t\n a lone gopher \n\t\r\n"))) // Output: a lone gopher } +func ExampleTrimSuffix() { + var b = []byte("Hello, goodbye, etc!") + b = bytes.TrimSuffix(b, []byte("goodbye, etc!")) + b = bytes.TrimSuffix(b, []byte("gopher")) + b = append(b, bytes.TrimSuffix([]byte("world!"), []byte("x!"))...) + os.Stdout.Write(b) + // Output: Hello, world! +} + func ExampleTrimRight() { fmt.Print(string(bytes.TrimRight([]byte("453gopher8257"), "0123456789"))) // Output: @@ -443,21 +453,6 @@ func ExampleTrimRightFunc() { // 1234go-gopher! } -func ExampleToUpper() { - fmt.Printf("%s", bytes.ToUpper([]byte("Gopher"))) - // Output: GOPHER -} - -func ExampleToUpperSpecial() { - str := []byte("ahoj vývojári golang") - totitle := bytes.ToUpperSpecial(unicode.AzeriCase, str) - fmt.Println("Original : " + string(str)) - fmt.Println("ToUpper : " + string(totitle)) - // Output: - // Original : ahoj vývojári golang - // ToUpper : AHOJ VÝVOJÁRİ GOLANG -} - func ExampleToLower() { fmt.Printf("%s", bytes.ToLower([]byte("Gopher"))) // Output: gopher @@ -473,10 +468,17 @@ func ExampleToLowerSpecial() { // ToLower : ahoj vývojári golang } -func ExampleReader_Len() { - fmt.Println(bytes.NewReader([]byte("Hi!")).Len()) - fmt.Println(bytes.NewReader([]byte("こんにちは!")).Len()) +func ExampleToUpper() { + fmt.Printf("%s", bytes.ToUpper([]byte("Gopher"))) + // Output: GOPHER +} + +func ExampleToUpperSpecial() { + str := []byte("ahoj vývojári golang") + totitle := bytes.ToUpperSpecial(unicode.AzeriCase, str) + fmt.Println("Original : " + string(str)) + fmt.Println("ToUpper : " + string(totitle)) // Output: - // 3 - // 16 + // Original : ahoj vývojári golang + // ToUpper : AHOJ VÝVOJÁRİ GOLANG } -- 2.39.1