365 lines
10 KiB
Go
365 lines
10 KiB
Go
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/*
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Copyright 2014 Alexander Okoli
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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/*
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Package goutils provides utility functions to manipulate strings in various ways.
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The code snippets below show examples of how to use goutils. Some functions return
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errors while others do not, so usage would vary as a result.
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Example:
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package main
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import (
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"fmt"
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"github.com/aokoli/goutils"
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)
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func main() {
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// EXAMPLE 1: A goutils function which returns no errors
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fmt.Println (goutils.Initials("John Doe Foo")) // Prints out "JDF"
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// EXAMPLE 2: A goutils function which returns an error
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rand1, err1 := goutils.Random (-1, 0, 0, true, true)
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if err1 != nil {
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fmt.Println(err1) // Prints out error message because -1 was entered as the first parameter in goutils.Random(...)
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} else {
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fmt.Println(rand1)
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}
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}
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*/
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package goutils
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import (
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"bytes"
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"strings"
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"unicode"
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)
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// VERSION indicates the current version of goutils
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const VERSION = "1.0.0"
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/*
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Wrap wraps a single line of text, identifying words by ' '.
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New lines will be separated by '\n'. Very long words, such as URLs will not be wrapped.
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Leading spaces on a new line are stripped. Trailing spaces are not stripped.
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Parameters:
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str - the string to be word wrapped
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wrapLength - the column (a column can fit only one character) to wrap the words at, less than 1 is treated as 1
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Returns:
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a line with newlines inserted
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*/
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func Wrap (str string, wrapLength int) string {
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return WrapCustom (str, wrapLength, "", false)
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}
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/*
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WrapCustom wraps a single line of text, identifying words by ' '.
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Leading spaces on a new line are stripped. Trailing spaces are not stripped.
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Parameters:
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str - the string to be word wrapped
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wrapLength - the column number (a column can fit only one character) to wrap the words at, less than 1 is treated as 1
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newLineStr - the string to insert for a new line, "" uses '\n'
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wrapLongWords - true if long words (such as URLs) should be wrapped
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Returns:
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a line with newlines inserted
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*/
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func WrapCustom (str string, wrapLength int, newLineStr string, wrapLongWords bool) string {
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if str == "" {
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return ""
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}
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if newLineStr == "" {
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newLineStr = "\n" // TODO Assumes "\n" is seperator. Explore SystemUtils.LINE_SEPARATOR from Apache Commons
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}
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if wrapLength < 1 {
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wrapLength = 1
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}
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inputLineLength := len(str)
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offset := 0
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var wrappedLine bytes.Buffer
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for inputLineLength-offset > wrapLength {
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if rune(str[offset]) == ' ' {
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offset++
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continue
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}
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end := wrapLength + offset + 1
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spaceToWrapAt := strings.LastIndex(str[offset:end], " ") + offset
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if spaceToWrapAt >= offset {
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// normal word (not longer than wrapLength)
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wrappedLine.WriteString(str[offset:spaceToWrapAt])
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wrappedLine.WriteString(newLineStr)
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offset = spaceToWrapAt + 1
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} else {
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// long word or URL
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if wrapLongWords {
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end := wrapLength + offset
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// long words are wrapped one line at a time
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wrappedLine.WriteString(str[offset:end])
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wrappedLine.WriteString(newLineStr)
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offset += wrapLength
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} else {
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// long words aren't wrapped, just extended beyond limit
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end := wrapLength + offset
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spaceToWrapAt = strings.IndexRune(str[end:len(str)], ' ') + end
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if spaceToWrapAt >= 0 {
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wrappedLine.WriteString(str[offset:spaceToWrapAt])
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wrappedLine.WriteString(newLineStr)
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offset = spaceToWrapAt + 1
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} else {
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wrappedLine.WriteString(str[offset:len(str)])
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offset = inputLineLength
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}
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}
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}
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}
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wrappedLine.WriteString(str[offset:len(str)])
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return wrappedLine.String()
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}
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/*
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Capitalize capitalizes all the delimiter separated words in a string. Only the first letter of each word is changed.
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To convert the rest of each word to lowercase at the same time, use CapitalizeFully(str string, delimiters ...rune).
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The delimiters represent a set of characters understood to separate words. The first string character
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and the first non-delimiter character after a delimiter will be capitalized. A "" input string returns "".
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Capitalization uses the Unicode title case, normally equivalent to upper case.
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Parameters:
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str - the string to capitalize
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delimiters - set of characters to determine capitalization, exclusion of this parameter means whitespace would be delimeter
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Returns:
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capitalized string
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*/
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func Capitalize (str string, delimiters ...rune) string {
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var delimLen int
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if delimiters == nil {
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delimLen = -1
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} else {
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delimLen = len(delimiters)
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}
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if str == "" || delimLen == 0 {
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return str;
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}
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buffer := []rune(str)
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capitalizeNext := true
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for i := 0; i < len(buffer); i++ {
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ch := buffer[i]
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if isDelimiter(ch, delimiters...) {
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capitalizeNext = true
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} else if capitalizeNext {
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buffer[i] = unicode.ToTitle(ch)
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capitalizeNext = false
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}
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}
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return string(buffer)
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}
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/*
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CapitalizeFully converts all the delimiter separated words in a string into capitalized words, that is each word is made up of a
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titlecase character and then a series of lowercase characters. The delimiters represent a set of characters understood
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to separate words. The first string character and the first non-delimiter character after a delimiter will be capitalized.
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Capitalization uses the Unicode title case, normally equivalent to upper case.
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Parameters:
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str - the string to capitalize fully
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delimiters - set of characters to determine capitalization, exclusion of this parameter means whitespace would be delimeter
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Returns:
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capitalized string
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*/
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func CapitalizeFully (str string, delimiters ...rune) string {
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var delimLen int
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if delimiters == nil {
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delimLen = -1
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} else {
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delimLen = len(delimiters)
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}
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if str == "" || delimLen == 0 {
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return str;
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}
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str = strings.ToLower(str)
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return Capitalize(str, delimiters...);
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}
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/*
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Uncapitalize uncapitalizes all the whitespace separated words in a string. Only the first letter of each word is changed.
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The delimiters represent a set of characters understood to separate words. The first string character and the first non-delimiter
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character after a delimiter will be uncapitalized. Whitespace is defined by unicode.IsSpace(char).
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Parameters:
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str - the string to uncapitalize fully
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delimiters - set of characters to determine capitalization, exclusion of this parameter means whitespace would be delimeter
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Returns:
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uncapitalized string
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*/
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func Uncapitalize (str string, delimiters ...rune) string {
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var delimLen int
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if delimiters == nil {
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delimLen = -1
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} else {
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delimLen = len(delimiters)
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}
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if str == "" || delimLen == 0 {
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return str;
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}
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buffer := []rune(str)
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uncapitalizeNext := true // TODO Always makes capitalize/un apply to first char.
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for i := 0; i < len(buffer); i++ {
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ch := buffer[i]
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if isDelimiter(ch, delimiters...) {
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uncapitalizeNext = true
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} else if uncapitalizeNext {
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buffer[i] = unicode.ToLower(ch)
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uncapitalizeNext = false
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}
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}
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return string(buffer)
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}
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/*
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SwapCase swaps the case of a string using a word based algorithm.
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Conversion algorithm:
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Upper case character converts to Lower case
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Title case character converts to Lower case
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Lower case character after Whitespace or at start converts to Title case
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Other Lower case character converts to Upper case
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Whitespace is defined by unicode.IsSpace(char).
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Parameters:
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str - the string to swap case
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Returns:
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the changed string
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*/
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func SwapCase(str string) string {
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if str == "" {
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return str
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}
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buffer := []rune(str)
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whitespace := true
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for i := 0; i < len(buffer); i++ {
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ch := buffer[i]
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if unicode.IsUpper(ch) {
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buffer[i] = unicode.ToLower(ch)
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whitespace = false
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} else if unicode.IsTitle(ch) {
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buffer[i] = unicode.ToLower(ch)
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whitespace = false
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} else if unicode.IsLower(ch) {
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if whitespace {
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buffer[i] = unicode.ToTitle(ch)
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whitespace = false
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} else {
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buffer[i] = unicode.ToUpper(ch)
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}
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} else {
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whitespace = unicode.IsSpace(ch)
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}
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}
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return string(buffer);
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}
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/*
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Initials extracts the initial letters from each word in the string. The first letter of the string and all first
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letters after the defined delimiters are returned as a new string. Their case is not changed. If the delimiters
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parameter is excluded, then Whitespace is used. Whitespace is defined by unicode.IsSpacea(char). An empty delimiter array returns an empty string.
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Parameters:
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str - the string to get initials from
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delimiters - set of characters to determine words, exclusion of this parameter means whitespace would be delimeter
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Returns:
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string of initial letters
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*/
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func Initials(str string, delimiters ...rune) string {
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if str == "" {
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return str
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}
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if delimiters != nil && len(delimiters) == 0 {
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return ""
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}
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strLen := len(str)
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var buf bytes.Buffer
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lastWasGap := true
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for i := 0; i < strLen; i++ {
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ch := rune(str[i])
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if isDelimiter(ch, delimiters...) {
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lastWasGap = true
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} else if lastWasGap {
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buf.WriteRune(ch)
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lastWasGap = false
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}
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}
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return buf.String()
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}
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// private function (lower case func name)
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func isDelimiter(ch rune, delimiters ...rune) bool {
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if delimiters == nil {
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return unicode.IsSpace(ch)
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}
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for _, delimiter := range delimiters {
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if ch == delimiter {
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return true
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}
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}
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return false
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}
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