forked from scionproto/scion
/
padding.go
42 lines (37 loc) · 1.16 KB
/
padding.go
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// Copyright 2016 ETH Zurich
//
// 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 util
import (
"github.com/scionproto/scion/go/lib/common"
)
// CalcPadding returns the number of padding bytes needed to round length bytes
// to a multiple of blkSize
func CalcPadding(length, blkSize int) int {
spare := length % blkSize
if spare != 0 {
return blkSize - spare
}
return 0
}
func PaddedLen(length, blkSize int) int {
return length + CalcPadding(length, blkSize)
}
func FillPadding(b common.RawBytes, length, blkSize int) int {
padding := CalcPadding(length, blkSize)
total := length + padding
for i := range b[length:total] {
b[length+i] = 0
}
return total
}