50 lines
1.4 KiB
Go
50 lines
1.4 KiB
Go
/*
|
|
* Copyright 2020 The Dragonfly 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,
|
|
* 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 "math"
|
|
|
|
const (
|
|
// DefaultPieceSize 4M
|
|
DefaultPieceSize = 4 * 1024 * 1024
|
|
|
|
// DefaultPieceSizeLimit 15M
|
|
DefaultPieceSizeLimit = 15 * 1024 * 1024
|
|
)
|
|
|
|
// ComputePieceSize computes the piece size with specified fileLength.
|
|
//
|
|
// If the fileLength<0, which means failed to get fileLength
|
|
// and then use the DefaultPieceSize.
|
|
func ComputePieceSize(length int64) uint32 {
|
|
if length <= 200*1024*1024 {
|
|
return DefaultPieceSize
|
|
}
|
|
|
|
gapCount := length / int64(100*1024*1024)
|
|
mpSize := (gapCount-2)*1024*1024 + DefaultPieceSize
|
|
if mpSize > DefaultPieceSizeLimit {
|
|
return DefaultPieceSizeLimit
|
|
}
|
|
return uint32(mpSize)
|
|
}
|
|
|
|
// ComputePieceCount returns piece count with given length and pieceSize
|
|
func ComputePieceCount(length int64, pieceSize uint32) int32 {
|
|
return int32(math.Ceil(float64(length) / float64(pieceSize)))
|
|
}
|