containerd/vendor/github.com/klauspost/compress/zstd/matchlen_generic.go
Akihiro Suda 1f2216cc78
go.mod: github.com/klauspost/compress v1.16.7
https://github.com/imdario/mergo/compare/v0.3.13...v1.0.0

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
2023-07-23 03:08:00 +09:00

34 lines
675 B
Go

//go:build !amd64 || appengine || !gc || noasm
// +build !amd64 appengine !gc noasm
// Copyright 2019+ Klaus Post. All rights reserved.
// License information can be found in the LICENSE file.
package zstd
import (
"encoding/binary"
"math/bits"
)
// matchLen returns the maximum common prefix length of a and b.
// a must be the shortest of the two.
func matchLen(a, b []byte) (n int) {
for ; len(a) >= 8 && len(b) >= 8; a, b = a[8:], b[8:] {
diff := binary.LittleEndian.Uint64(a) ^ binary.LittleEndian.Uint64(b)
if diff != 0 {
return n + bits.TrailingZeros64(diff)>>3
}
n += 8
}
for i := range a {
if a[i] != b[i] {
break
}
n++
}
return n
}