neoneo-go/pkg/core/mpt/helpers.go
2021-01-13 12:25:27 +03:00

49 lines
890 B
Go

package mpt
// lcp returns longest common prefix of a and b.
// Note: it does no allocations.
func lcp(a, b []byte) []byte {
if len(a) < len(b) {
return lcp(b, a)
}
var i int
for i = 0; i < len(b); i++ {
if a[i] != b[i] {
break
}
}
return a[:i]
}
func lcpMany(kv []keyValue) []byte {
if len(kv) == 1 {
return kv[0].key
}
p := lcp(kv[0].key, kv[1].key)
if len(p) == 0 {
return p
}
for i := range kv[2:] {
p = lcp(p, kv[2+i].key)
}
return p
}
// copySlice is a helper for copying slice if needed.
func copySlice(a []byte) []byte {
b := make([]byte, len(a))
copy(b, a)
return b
}
// toNibbles mangles path by splitting every byte into 2 containing low- and high- 4-byte part.
func toNibbles(path []byte) []byte {
result := make([]byte, len(path)*2)
for i := range path {
result[i*2] = path[i] >> 4
result[i*2+1] = path[i] & 0x0F
}
return result
}