1
0
mirror of https://github.com/fumiama/unibase2n.git synced 2026-06-07 18:02:39 +08:00
Files
unibase2n/decode.go
2022-10-01 15:30:15 +08:00

64 lines
1.3 KiB
Go

package unibase2n
import (
"encoding/binary"
)
func (bs Base) Decode(data []byte) []byte {
return nil
}
// dec128blk1 for bit 1
// len(in)>0, len(in)%16==0, len(out)==len(in)/16
func dec128blk1(mask uint128be, in, out []byte) {
for i := range out {
c := i * 16
n := readuint128be(in[c : c+16])
one := u128one
n.subeq(mask)
sum := n.and(one)
n.shreq(16 - 1)
one.shleq(1)
sum.oreq(n.and(one))
n.shreq(16 - 1)
one.shleq(1)
sum.oreq(n.and(one))
n.shreq(16 - 1)
one.shleq(1)
sum.oreq(n.and(one))
n.shreq(16 - 1)
one.shleq(1)
sum.oreq(n.and(one))
n.shreq(16 - 1)
one.shleq(1)
sum.oreq(n.and(one))
n.shreq(16 - 1)
one.shleq(1)
sum.oreq(n.and(one))
n.shreq(16 - 1)
one.shleq(1)
sum.oreq(n.and(one))
out[i] = uint8(sum.b)
}
}
// dec64blk2 for bit 2
// len(in)!=0, len(out)==len(in)/8
func dec64blk2(mask uint64, in, out []byte) {
for i, n := range in {
c := i * 8
x := (uint64(n)<<42 | uint64(n)<<28 | uint64(n)<<14 | uint64(n)) & 0x00030003_00030003
binary.BigEndian.PutUint64(out[c:c+8], x+mask)
}
}
// dec32blk4 for bit 4
// len(in)!=0, len(out)==len(in)/4
func dec32blk4(mask uint32, in, out []byte) {
for i, n := range in {
c := i * 4
x := (uint32(n)<<12 | uint32(n)) & 0x000f000f
binary.BigEndian.PutUint32(out[c:c+4], x+mask)
}
}