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minimumPieceLength from 16KB to 64KB, add maximumPieceLength 2MB-, piecelength priority is over piece numbr priority

This commit is contained in:
whr819987540 2023-04-27 12:04:53 +08:00
parent ff11917fa8
commit 16debff467
1 changed files with 15 additions and 7 deletions
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22
metainfo/piece-length.go
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@ -30,9 +30,14 @@
package metainfo
import (
"math"
)
// For more context on why these numbers, see http://wiki.vuze.com/w/Torrent_Piece_Size
const (
minimumPieceLength = 16 * 1024
minimumPieceLength = 64 * 1024
maximumPieceLength = 2 * 1024 * 1024
targetPieceCountLog2 = 10
targetPieceCountMin = 1 << targetPieceCountLog2
)
@ -41,16 +46,19 @@ const (
const targetPieceCountMax = targetPieceCountMin << 1
// Choose a good piecelength.
// piecelength >= 16KB
// piecelength = 16KB*X
// totalLength / piecelength = piecenumber < 2048
// piecelength >= 64KB and piecelength <= 2MB
// piecelength = 64KB*X
// totalLength / piecelength = piecenumber <= 2048
func ChoosePieceLength(totalLength int64) (pieceLength int64) {
// Must be a power of 2.
// Must be a multiple of 16KB
// Must be a multiple of 64KB
// Prefer to provide around 1024..2048 pieces.
pieceLength = minimumPieceLength
pieces := totalLength / pieceLength
for pieces >= targetPieceCountMax {
pieces := int64(math.Ceil(float64(totalLength) / float64(pieceLength)))
for pieces > targetPieceCountMax {
if (pieceLength << 1) > maximumPieceLength {
break
}
pieceLength <<= 1
pieces >>= 1
}