/
len.go
50 lines (42 loc) · 1.54 KB
/
len.go
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// Copyright 2020 Chaos Mesh Authors.
//
// 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,
// See the License for the specific language governing permissions and
// limitations under the License.
package netutils
import (
"crypto/sha1"
"fmt"
"log"
)
// CompressName compresses name to targetLength with specified postfix
// targetLength < 7 or targetLength-7-len(namePostFix) < 0 are not allowed
func CompressName(originalName string, targetLength int, namePostFix string) (name string) {
if targetLength < 7 {
log.Fatal("targetLength shouldn't be less than 7")
}
if targetLength-7-len(namePostFix) < 0 {
log.Fatalf("namePostFix longer than (targetLength-7) = %d: %s", targetLength-7, namePostFix)
}
if len(originalName) < 6 {
// len(originalName) < 6 && 7 + len(namePostFix) < targetlength
// => 1 + len(originalName) + len(namePostFix) < targetLength
name = originalName + "_" + namePostFix
return
}
namePrefix := originalName[0:5]
nameRest := originalName[5:]
hasher := sha1.New()
hasher.Write([]byte(nameRest))
hashValue := fmt.Sprintf("%x", hasher.Sum(nil))
// keep the length does not exceed targetLength
name = namePrefix + "_" + hashValue[0:targetLength-7-len(namePostFix)] + "_" + namePostFix
return
}