initial import

core/stringx/strings.go

@@ -0,0 +1,131 @@
+package stringx
+
+import (
+	"errors"
+
+	"zero/core/lang"
+)
+
+var (
+	ErrInvalidStartPosition = errors.New("start position is invalid")
+	ErrInvalidStopPosition  = errors.New("stop position is invalid")
+)
+
+func Contains(list []string, str string) bool {
+	for _, each := range list {
+		if each == str {
+			return true
+		}
+	}
+
+	return false
+}
+
+func Filter(s string, filter func(r rune) bool) string {
+	var n int
+	chars := []rune(s)
+	for i, x := range chars {
+		if n < i {
+			chars[n] = x
+		}
+		if !filter(x) {
+			n++
+		}
+	}
+
+	return string(chars[:n])
+}
+
+func HasEmpty(args ...string) bool {
+	for _, arg := range args {
+		if len(arg) == 0 {
+			return true
+		}
+	}
+
+	return false
+}
+
+func NotEmpty(args ...string) bool {
+	return !HasEmpty(args...)
+}
+
+func Remove(strings []string, strs ...string) []string {
+	out := append([]string(nil), strings...)
+
+	for _, str := range strs {
+		var n int
+		for _, v := range out {
+			if v != str {
+				out[n] = v
+				n++
+			}
+		}
+		out = out[:n]
+	}
+
+	return out
+}
+
+func Reverse(s string) string {
+	runes := []rune(s)
+
+	for from, to := 0, len(runes)-1; from < to; from, to = from+1, to-1 {
+		runes[from], runes[to] = runes[to], runes[from]
+	}
+
+	return string(runes)
+}
+
+// Substr returns runes between start and stop [start, stop) regardless of the chars are ascii or utf8
+func Substr(str string, start int, stop int) (string, error) {
+	rs := []rune(str)
+	length := len(rs)
+
+	if start < 0 || start > length {
+		return "", ErrInvalidStartPosition
+	}
+
+	if stop < 0 || stop > length {
+		return "", ErrInvalidStopPosition
+	}
+
+	return string(rs[start:stop]), nil
+}
+
+func TakeOne(valid, or string) string {
+	if len(valid) > 0 {
+		return valid
+	} else {
+		return or
+	}
+}
+
+func TakeWithPriority(fns ...func() string) string {
+	for _, fn := range fns {
+		val := fn()
+		if len(val) > 0 {
+			return val
+		}
+	}
+
+	return ""
+}
+
+func Union(first, second []string) []string {
+	set := make(map[string]lang.PlaceholderType)
+
+	for _, each := range first {
+		set[each] = lang.Placeholder
+	}
+	for _, each := range second {
+		set[each] = lang.Placeholder
+	}
+
+	merged := make([]string, 0, len(set))
+	for k := range set {
+		merged = append(merged, k)
+	}
+
+	return merged
+}