forked from TrueCloudLab/neoneo-go
42 lines
750 B
Go
42 lines
750 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
|
|
}
|
|
|
|
// 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
|
|
}
|