You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
34 lines
675 B
34 lines
675 B
//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
|
|
|
|
}
|