AdGuardHome/internal/aghstrings/strings.go

90 lines
1.8 KiB
Go

// Package aghstrings contains utilities dealing with strings.
package aghstrings
import (
"strings"
)
// CloneSliceOrEmpty returns the copy of a or empty strings slice if a is nil.
func CloneSliceOrEmpty(a []string) (b []string) {
return append([]string{}, a...)
}
// CloneSlice returns the exact copy of a.
func CloneSlice(a []string) (b []string) {
if a == nil {
return nil
}
return CloneSliceOrEmpty(a)
}
// FilterOut returns a copy of strs with all strings for which f returned true
// removed.
func FilterOut(strs []string, f func(s string) (ok bool)) (filtered []string) {
for _, s := range strs {
if !f(s) {
filtered = append(filtered, s)
}
}
return filtered
}
// InSlice checks if string is in the slice of strings.
func InSlice(strs []string, str string) (ok bool) {
for _, s := range strs {
if s == str {
return true
}
}
return false
}
// IsCommentOrEmpty returns true of the string starts with a "#" character or is
// an empty string.
func IsCommentOrEmpty(s string) (ok bool) {
return len(s) == 0 || s[0] == '#'
}
// SplitNext splits string by a byte and returns the first chunk skipping empty
// ones. Whitespaces are trimmed.
func SplitNext(s *string, sep rune) (chunk string) {
if s == nil {
return chunk
}
i := strings.IndexByte(*s, byte(sep))
if i == -1 {
chunk = *s
*s = ""
return strings.TrimSpace(chunk)
}
chunk = (*s)[:i]
*s = (*s)[i+1:]
var j int
var r rune
for j, r = range *s {
if r != sep {
break
}
}
*s = (*s)[j:]
return strings.TrimSpace(chunk)
}
// WriteToBuilder is a convenient wrapper for strings.(*Builder).WriteString
// that deals with multiple strings and ignores errors that are guaranteed to be
// nil.
func WriteToBuilder(b *strings.Builder, strs ...string) {
// TODO(e.burkov): Recover from panic?
for _, s := range strs {
_, _ = b.WriteString(s)
}
}