diff options
Diffstat (limited to 'vendor/github.com/huandu/xstrings/format.go')
-rw-r--r-- | vendor/github.com/huandu/xstrings/format.go | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/vendor/github.com/huandu/xstrings/format.go b/vendor/github.com/huandu/xstrings/format.go new file mode 100644 index 0000000000..2d02df1c04 --- /dev/null +++ b/vendor/github.com/huandu/xstrings/format.go @@ -0,0 +1,170 @@ +// Copyright 2015 Huan Du. All rights reserved. +// Licensed under the MIT license that can be found in the LICENSE file. + +package xstrings + +import ( + "bytes" + "unicode/utf8" +) + +// ExpandTabs can expand tabs ('\t') rune in str to one or more spaces dpending on +// current column and tabSize. +// The column number is reset to zero after each newline ('\n') occurring in the str. +// +// ExpandTabs uses RuneWidth to decide rune's width. +// For example, CJK characters will be treated as two characters. +// +// If tabSize <= 0, ExpandTabs panics with error. +// +// Samples: +// ExpandTabs("a\tbc\tdef\tghij\tk", 4) => "a bc def ghij k" +// ExpandTabs("abcdefg\thij\nk\tl", 4) => "abcdefg hij\nk l" +// ExpandTabs("z中\t文\tw", 4) => "z中 文 w" +func ExpandTabs(str string, tabSize int) string { + if tabSize <= 0 { + panic("tab size must be positive") + } + + var r rune + var i, size, column, expand int + var output *bytes.Buffer + + orig := str + + for len(str) > 0 { + r, size = utf8.DecodeRuneInString(str) + + if r == '\t' { + expand = tabSize - column%tabSize + + if output == nil { + output = allocBuffer(orig, str) + } + + for i = 0; i < expand; i++ { + output.WriteByte(byte(' ')) + } + + column += expand + } else { + if r == '\n' { + column = 0 + } else { + column += RuneWidth(r) + } + + if output != nil { + output.WriteRune(r) + } + } + + str = str[size:] + } + + if output == nil { + return orig + } + + return output.String() +} + +// LeftJustify returns a string with pad string at right side if str's rune length is smaller than length. +// If str's rune length is larger than length, str itself will be returned. +// +// If pad is an empty string, str will be returned. +// +// Samples: +// LeftJustify("hello", 4, " ") => "hello" +// LeftJustify("hello", 10, " ") => "hello " +// LeftJustify("hello", 10, "123") => "hello12312" +func LeftJustify(str string, length int, pad string) string { + l := Len(str) + + if l >= length || pad == "" { + return str + } + + remains := length - l + padLen := Len(pad) + + output := &bytes.Buffer{} + output.Grow(len(str) + (remains/padLen+1)*len(pad)) + output.WriteString(str) + writePadString(output, pad, padLen, remains) + return output.String() +} + +// RightJustify returns a string with pad string at left side if str's rune length is smaller than length. +// If str's rune length is larger than length, str itself will be returned. +// +// If pad is an empty string, str will be returned. +// +// Samples: +// RightJustify("hello", 4, " ") => "hello" +// RightJustify("hello", 10, " ") => " hello" +// RightJustify("hello", 10, "123") => "12312hello" +func RightJustify(str string, length int, pad string) string { + l := Len(str) + + if l >= length || pad == "" { + return str + } + + remains := length - l + padLen := Len(pad) + + output := &bytes.Buffer{} + output.Grow(len(str) + (remains/padLen+1)*len(pad)) + writePadString(output, pad, padLen, remains) + output.WriteString(str) + return output.String() +} + +// Center returns a string with pad string at both side if str's rune length is smaller than length. +// If str's rune length is larger than length, str itself will be returned. +// +// If pad is an empty string, str will be returned. +// +// Samples: +// Center("hello", 4, " ") => "hello" +// Center("hello", 10, " ") => " hello " +// Center("hello", 10, "123") => "12hello123" +func Center(str string, length int, pad string) string { + l := Len(str) + + if l >= length || pad == "" { + return str + } + + remains := length - l + padLen := Len(pad) + + output := &bytes.Buffer{} + output.Grow(len(str) + (remains/padLen+1)*len(pad)) + writePadString(output, pad, padLen, remains/2) + output.WriteString(str) + writePadString(output, pad, padLen, (remains+1)/2) + return output.String() +} + +func writePadString(output *bytes.Buffer, pad string, padLen, remains int) { + var r rune + var size int + + repeats := remains / padLen + + for i := 0; i < repeats; i++ { + output.WriteString(pad) + } + + remains = remains % padLen + + if remains != 0 { + for i := 0; i < remains; i++ { + r, size = utf8.DecodeRuneInString(pad) + output.WriteRune(r) + pad = pad[size:] + } + } +} |