feature: allow specify offset in name pattern

pkg/util/stringutils2/namepattern.go

@@ -0,0 +1,53 @@
+// Copyright 2019 Yunion
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package stringutils2
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+// name##
+// name##9#
+func ParseNamePattern2(name string) (string, string, int, int) {
+	const RepChar = '#'
+	var match string
+	var pattern string
+	var patternLen int
+	var offset int
+
+	start := strings.IndexByte(name, RepChar)
+	if start >= 0 {
+		end := start + 1
+		for end < len(name) && name[end] == RepChar {
+			end += 1
+		}
+		patternLen = end - start
+		nend := strings.IndexByte(name[end:], RepChar)
+		if nend > 0 {
+			if oi, err := strconv.ParseInt(name[end:end+nend], 10, 64); err == nil {
+				offset = int(oi)
+			}
+			end = end + nend + 1
+		}
+		match = fmt.Sprintf("%s%%%s", name[:start], name[end:])
+		pattern = fmt.Sprintf("%s%%0%dd%s", name[:start], patternLen, name[end:])
+	} else {
+		match = fmt.Sprintf("%s-%%", name)
+		pattern = fmt.Sprintf("%s-%%d", name)
+	}
+	return match, pattern, patternLen, offset
+}