dnscrypt-proxy/vendor/github.com/ettle/strcase/convert.go

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2021-07-03 10:56:53 +02:00
package strcase
import "strings"
// WordCase is an enumeration of the ways to format a word.
type WordCase int
const (
// Original - Preserve the original input strcase
Original WordCase = iota
// LowerCase - All letters lower cased (example)
LowerCase
// UpperCase - All letters upper cased (EXAMPLE)
UpperCase
// TitleCase - Only first letter upper cased (Example)
TitleCase
// CamelCase - TitleCase except lower case first word (exampleText)
// Notably, even if the first word is an initialism, it will be lower
// cased. This is important for code generators where capital letters
// mean exported functions. i.e. jsonString(), not JSONString()
CamelCase
)
// We have 3 convert functions for performance reasons
// The general convert could handle everything, but is not optimized
//
// The other two functions are optimized for the general use cases - that is the non-custom caser functions
// Case 1: Any Case and supports Go Initialisms
// Case 2: UpperCase words, which don't need to support initialisms since everything is in upper case
// convertWithoutInitialims only works for to UpperCase and LowerCase
//nolint:gocyclo
func convertWithoutInitialisms(input string, delimiter rune, wordCase WordCase) string {
input = strings.TrimSpace(input)
runes := []rune(input)
if len(runes) == 0 {
return ""
}
var b strings.Builder
b.Grow(len(input) * 2) // In case we need to write delimiters where they weren't before
var prev, curr rune
next := runes[0] // 0 length will have already returned so safe to index
inWord := false
firstWord := true
for i := 0; i < len(runes); i++ {
prev = curr
curr = next
if i+1 == len(runes) {
next = 0
} else {
next = runes[i+1]
}
switch defaultSplitFn(prev, curr, next) {
case SkipSplit:
if inWord && delimiter != 0 {
b.WriteRune(delimiter)
}
inWord = false
continue
case Split:
if inWord && delimiter != 0 {
b.WriteRune(delimiter)
}
inWord = false
}
switch wordCase {
case UpperCase:
b.WriteRune(toUpper(curr))
case LowerCase:
b.WriteRune(toLower(curr))
case TitleCase:
if inWord {
b.WriteRune(toLower(curr))
} else {
b.WriteRune(toUpper(curr))
}
case CamelCase:
if inWord {
b.WriteRune(toLower(curr))
} else if firstWord {
b.WriteRune(toLower(curr))
firstWord = false
} else {
b.WriteRune(toUpper(curr))
}
default:
// Must be original case
b.WriteRune(curr)
}
inWord = inWord || true
}
return b.String()
}
// convertWithGoInitialisms changes a input string to a certain case with a
// delimiter, respecting go initialisms but not skip runes
//nolint:gocyclo
func convertWithGoInitialisms(input string, delimiter rune, wordCase WordCase) string {
input = strings.TrimSpace(input)
runes := []rune(input)
if len(runes) == 0 {
return ""
}
var b strings.Builder
b.Grow(len(input) * 2) // In case we need to write delimiters where they weren't before
firstWord := true
addWord := func(start, end int) {
if start == end {
return
}
if !firstWord && delimiter != 0 {
b.WriteRune(delimiter)
}
// Don't bother with initialisms if the word is longer than 5
// A quick proxy to avoid the extra memory allocations
if end-start <= 5 {
key := strings.ToUpper(string(runes[start:end]))
if golintInitialisms[key] {
if !firstWord || wordCase != CamelCase {
b.WriteString(key)
firstWord = false
return
}
}
}
for i := start; i < end; i++ {
r := runes[i]
switch wordCase {
case UpperCase:
panic("use convertWithoutInitialisms instead")
case LowerCase:
b.WriteRune(toLower(r))
case TitleCase:
if i == start {
b.WriteRune(toUpper(r))
} else {
b.WriteRune(toLower(r))
}
case CamelCase:
if !firstWord && i == start {
b.WriteRune(toUpper(r))
} else {
b.WriteRune(toLower(r))
}
default:
b.WriteRune(r)
}
}
firstWord = false
}
var prev, curr rune
next := runes[0] // 0 length will have already returned so safe to index
wordStart := 0
for i := 0; i < len(runes); i++ {
prev = curr
curr = next
if i+1 == len(runes) {
next = 0
} else {
next = runes[i+1]
}
switch defaultSplitFn(prev, curr, next) {
case Split:
addWord(wordStart, i)
wordStart = i
case SkipSplit:
addWord(wordStart, i)
wordStart = i + 1
}
}
if wordStart != len(runes) {
addWord(wordStart, len(runes))
}
return b.String()
}
// convert changes a input string to a certain case with a delimiter,
// respecting arbitrary initialisms and skip characters
//nolint:gocyclo
func convert(input string, fn SplitFn, delimiter rune, wordCase WordCase,
initialisms map[string]bool) string {
input = strings.TrimSpace(input)
runes := []rune(input)
if len(runes) == 0 {
return ""
}
var b strings.Builder
b.Grow(len(input) * 2) // In case we need to write delimiters where they weren't before
firstWord := true
var skipIndexes []int
addWord := func(start, end int) {
// If you have nothing good to say, say nothing at all
if start == end || len(skipIndexes) == end-start {
skipIndexes = nil
return
}
// If you have something to say, start with a delimiter
if !firstWord && delimiter != 0 {
b.WriteRune(delimiter)
}
// Check if you're an initialism
// Note - we don't check skip characters here since initialisms
// will probably never have junk characters in between
// I'm open to it if there is a use case
if initialisms != nil {
var word strings.Builder
for i := start; i < end; i++ {
word.WriteRune(toUpper(runes[i]))
}
key := word.String()
if initialisms[key] {
if !firstWord || wordCase != CamelCase {
b.WriteString(key)
firstWord = false
return
}
}
}
skipIdx := 0
for i := start; i < end; i++ {
if len(skipIndexes) > 0 && skipIdx < len(skipIndexes) && i == skipIndexes[skipIdx] {
skipIdx++
continue
}
r := runes[i]
switch wordCase {
case UpperCase:
b.WriteRune(toUpper(r))
case LowerCase:
b.WriteRune(toLower(r))
case TitleCase:
if i == start {
b.WriteRune(toUpper(r))
} else {
b.WriteRune(toLower(r))
}
case CamelCase:
if !firstWord && i == start {
b.WriteRune(toUpper(r))
} else {
b.WriteRune(toLower(r))
}
default:
b.WriteRune(r)
}
}
firstWord = false
skipIndexes = nil
}
var prev, curr rune
next := runes[0] // 0 length will have already returned so safe to index
wordStart := 0
for i := 0; i < len(runes); i++ {
prev = curr
curr = next
if i+1 == len(runes) {
next = 0
} else {
next = runes[i+1]
}
switch fn(prev, curr, next) {
case Skip:
skipIndexes = append(skipIndexes, i)
case Split:
addWord(wordStart, i)
wordStart = i
case SkipSplit:
addWord(wordStart, i)
wordStart = i + 1
}
}
if wordStart != len(runes) {
addWord(wordStart, len(runes))
}
return b.String()
}