replace zxq.co/ripple/hanayo

vendor/github.com/felipeweb/gopher-utils/string.go

@@ -0,0 +1,126 @@
+package gopher_utils
+
+import (
+	"bytes"
+	"unicode"
+	"unicode/utf8"
+)
+
+// IsLetter returns true if the 'l' is an English letter.
+func IsLetter(l uint8) bool {
+	n := (l | 0x20) - 'a'
+	if n >= 0 && n < 26 {
+		return true
+	}
+	return false
+}
+
+// Reverse s string, support unicode
+func Reverse(s string) string {
+	n := len(s)
+	runes := make([]rune, n)
+	for _, rune := range s {
+		n--
+		runes[n] = rune
+	}
+	return string(runes[n:])
+}
+
+// ToSnakeCase can convert all upper case characters in a string to
+// underscore format.
+//
+// Some samples.
+//     "FirstName"  => "first_name"
+//     "HTTPServer" => "http_server"
+//     "NoHTTPS"    => "no_https"
+//     "GO_PATH"    => "go_path"
+//     "GO PATH"    => "go_path"      // space is converted to underscore.
+//     "GO-PATH"    => "go_path"      // hyphen is converted to underscore.
+//
+func ToSnakeCase(str string) string {
+	if len(str) == 0 {
+		return ""
+	}
+
+	buf := &bytes.Buffer{}
+	var prev, r0, r1 rune
+	var size int
+
+	r0 = '_'
+
+	for len(str) > 0 {
+		prev = r0
+		r0, size = utf8.DecodeRuneInString(str)
+		str = str[size:]
+
+		switch {
+		case r0 == utf8.RuneError:
+			buf.WriteByte(byte(str[0]))
+
+		case unicode.IsUpper(r0):
+			if prev != '_' {
+				buf.WriteRune('_')
+			}
+
+			buf.WriteRune(unicode.ToLower(r0))
+
+			if len(str) == 0 {
+				break
+			}
+
+			r0, size = utf8.DecodeRuneInString(str)
+			str = str[size:]
+
+			if !unicode.IsUpper(r0) {
+				buf.WriteRune(r0)
+				break
+			}
+
+			// find next non-upper-case character and insert `_` properly.
+			// it's designed to convert `HTTPServer` to `http_server`.
+			// if there are more than 2 adjacent upper case characters in a word,
+			// treat them as an abbreviation plus a normal word.
+			for len(str) > 0 {
+				r1 = r0
+				r0, size = utf8.DecodeRuneInString(str)
+				str = str[size:]
+
+				if r0 == utf8.RuneError {
+					buf.WriteRune(unicode.ToLower(r1))
+					buf.WriteByte(byte(str[0]))
+					break
+				}
+
+				if !unicode.IsUpper(r0) {
+					if r0 == '_' || r0 == ' ' || r0 == '-' {
+						r0 = '_'
+
+						buf.WriteRune(unicode.ToLower(r1))
+					} else {
+						buf.WriteRune('_')
+						buf.WriteRune(unicode.ToLower(r1))
+						buf.WriteRune(r0)
+					}
+
+					break
+				}
+
+				buf.WriteRune(unicode.ToLower(r1))
+			}
+
+			if len(str) == 0 || r0 == '_' {
+				buf.WriteRune(unicode.ToLower(r0))
+				break
+			}
+
+		default:
+			if r0 == ' ' || r0 == '-' {
+				r0 = '_'
+			}
+
+			buf.WriteRune(r0)
+		}
+	}
+
+	return buf.String()
+}