65 lines
1.4 KiB
Go
65 lines
1.4 KiB
Go
|
package utils
|
||
|
|
|
||
|
|
// HexToCompact converts a hex path to the compact encoded format
|
||
|
|
func HexToCompact(hex []byte) []byte {
|
||
|
|
return hexToCompact(hex)
|
||
|
|
}
|
||
|
|
|
||
|
|
func hexToCompact(hex []byte) []byte {
|
||
|
|
terminator := byte(0)
|
||
|
|
if hasTerm(hex) {
|
||
|
|
terminator = 1
|
||
|
|
hex = hex[:len(hex)-1]
|
||
|
|
}
|
||
|
|
buf := make([]byte, len(hex)/2+1)
|
||
|
|
buf[0] = terminator << 5 // the flag byte
|
||
|
|
if len(hex)&1 == 1 {
|
||
|
|
buf[0] |= 1 << 4 // odd flag
|
||
|
|
buf[0] |= hex[0] // first nibble is contained in the first byte
|
||
|
|
hex = hex[1:]
|
||
|
|
}
|
||
|
|
decodeNibbles(hex, buf[1:])
|
||
|
|
return buf
|
||
|
|
}
|
||
|
|
|
||
|
|
// CompactToHex converts a compact encoded path to hex format
|
||
|
|
func CompactToHex(compact []byte) []byte {
|
||
|
|
return compactToHex(compact)
|
||
|
|
}
|
||
|
|
|
||
|
|
func compactToHex(compact []byte) []byte {
|
||
|
|
if len(compact) == 0 {
|
||
|
|
return compact
|
||
|
|
}
|
||
|
|
base := KeybytesToHex(compact)
|
||
|
|
// delete terminator flag
|
||
|
|
if base[0] < 2 {
|
||
|
|
base = base[:len(base)-1]
|
||
|
|
}
|
||
|
|
// apply odd flag
|
||
|
|
chop := 2 - base[0]&1
|
||
|
|
return base[chop:]
|
||
|
|
}
|
||
|
|
|
||
|
|
func KeybytesToHex(str []byte) []byte {
|
||
|
|
l := len(str)*2 + 1
|
||
|
|
var nibbles = make([]byte, l)
|
||
|
|
for i, b := range str {
|
||
|
|
nibbles[i*2] = b / 16
|
||
|
|
nibbles[i*2+1] = b % 16
|
||
|
|
}
|
||
|
|
nibbles[l-1] = 16
|
||
|
|
return nibbles
|
||
|
|
}
|
||
|
|
|
||
|
|
func decodeNibbles(nibbles []byte, bytes []byte) {
|
||
|
|
for bi, ni := 0, 0; ni < len(nibbles); bi, ni = bi+1, ni+2 {
|
||
|
|
bytes[bi] = nibbles[ni]<<4 | nibbles[ni+1]
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// hasTerm returns whether a hex key has the terminator flag.
|
||
|
|
func hasTerm(s []byte) bool {
|
||
|
|
return len(s) > 0 && s[len(s)-1] == 16
|
||
|
|
}
|