+++ /dev/null
-package base58
-
-import (
- "fmt"
- "math/big"
-)
-
-var (
- bn0 = big.NewInt(0)
- bn58 = big.NewInt(58)
-)
-
-// TrivialBase58Encoding encodes the passed bytes into a base58 encoded string
-// (inefficiently).
-func TrivialBase58Encoding(a []byte) string {
- return TrivialBase58EncodingAlphabet(a, BTCAlphabet)
-}
-
-// TrivialBase58EncodingAlphabet encodes the passed bytes into a base58 encoded
-// string (inefficiently) with the passed alphabet.
-func TrivialBase58EncodingAlphabet(a []byte, alphabet *Alphabet) string {
- zero := alphabet.encode[0]
- idx := len(a)*138/100 + 1
- buf := make([]byte, idx)
- bn := new(big.Int).SetBytes(a)
- var mo *big.Int
- for bn.Cmp(bn0) != 0 {
- bn, mo = bn.DivMod(bn, bn58, new(big.Int))
- idx--
- buf[idx] = alphabet.encode[mo.Int64()]
- }
- for i := range a {
- if a[i] != 0 {
- break
- }
- idx--
- buf[idx] = zero
- }
- return string(buf[idx:])
-}
-
-// TrivialBase58Decoding decodes the base58 encoded bytes (inefficiently).
-func TrivialBase58Decoding(str string) ([]byte, error) {
- return TrivialBase58DecodingAlphabet(str, BTCAlphabet)
-}
-
-// TrivialBase58DecodingAlphabet decodes the base58 encoded bytes
-// (inefficiently) using the given b58 alphabet.
-func TrivialBase58DecodingAlphabet(str string, alphabet *Alphabet) ([]byte, error) {
- zero := alphabet.encode[0]
-
- var zcount int
- for i := 0; i < len(str) && str[i] == zero; i++ {
- zcount++
- }
- leading := make([]byte, zcount)
-
- var padChar rune = -1
- src := []byte(str)
- j := 0
- for ; j < len(src) && src[j] == byte(padChar); j++ {
- }
-
- n := new(big.Int)
- for i := range src[j:] {
- c := alphabet.decode[src[i]]
- if c == -1 {
- return nil, fmt.Errorf("illegal base58 data at input index: %d", i)
- }
- n.Mul(n, bn58)
- n.Add(n, big.NewInt(int64(c)))
- }
- return append(leading, n.Bytes()...), nil
-}