+++ /dev/null
-package base58
-
-import (
- "fmt"
- "math/big"
-)
-
-var (
- bn0 = big.NewInt(0)
- bn58 = big.NewInt(58)
-)
-
-// Encode encodes the passed bytes into a base58 encoded string.
-func Encode(bin []byte) string {
- return FastBase58Encoding(bin)
-}
-
-// EncodeAlphabet encodes the passed bytes into a base58 encoded string with the
-// passed alphabet.
-func EncodeAlphabet(bin []byte, alphabet *Alphabet) string {
- return FastBase58EncodingAlphabet(bin, alphabet)
-}
-
-// FastBase58Encoding encodes the passed bytes into a base58 encoded string.
-func FastBase58Encoding(bin []byte) string {
- return FastBase58EncodingAlphabet(bin, BTCAlphabet)
-}
-
-// FastBase58EncodingAlphabet encodes the passed bytes into a base58 encoded
-// string with the passed alphabet.
-func FastBase58EncodingAlphabet(bin []byte, alphabet *Alphabet) string {
- zero := alphabet.encode[0]
-
- binsz := len(bin)
- var i, j, zcount, high int
- var carry uint32
-
- for zcount < binsz && bin[zcount] == 0 {
- zcount++
- }
-
- size := (binsz-zcount)*138/100 + 1
- var buf = make([]byte, size)
-
- high = size - 1
- for i = zcount; i < binsz; i++ {
- j = size - 1
- for carry = uint32(bin[i]); j > high || carry != 0; j-- {
- carry = carry + 256*uint32(buf[j])
- buf[j] = byte(carry % 58)
- carry /= 58
- }
- high = j
- }
-
- for j = 0; j < size && buf[j] == 0; j++ {
- }
-
- var b58 = make([]byte, size-j+zcount)
-
- if zcount != 0 {
- for i = 0; i < zcount; i++ {
- b58[i] = zero
- }
- }
-
- for i = zcount; j < size; i++ {
- b58[i] = alphabet.encode[buf[j]]
- j++
- }
-
- return string(b58)
-}
-
-// 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:])
-}
-
-// Decode decodes the base58 encoded bytes.
-func Decode(str string) ([]byte, error) {
- return FastBase58Decoding(str)
-}
-
-// DecodeAlphabet decodes the base58 encoded bytes using the given b58 alphabet.
-func DecodeAlphabet(str string, alphabet *Alphabet) ([]byte, error) {
- return FastBase58DecodingAlphabet(str, alphabet)
-}
-
-// FastBase58Decoding decodes the base58 encoded bytes.
-func FastBase58Decoding(str string) ([]byte, error) {
- return FastBase58DecodingAlphabet(str, BTCAlphabet)
-}
-
-// FastBase58DecodingAlphabet decodes the base58 encoded bytes using the given
-// b58 alphabet.
-func FastBase58DecodingAlphabet(str string, alphabet *Alphabet) ([]byte, error) {
- if len(str) == 0 {
- return nil, fmt.Errorf("zero length string")
- }
-
- var (
- t uint64
- zmask, c uint32
- zcount int
-
- b58u = []rune(str)
- b58sz = len(b58u)
-
- outisz = (b58sz + 3) / 4 // check to see if we need to change this buffer size to optimize
- binu = make([]byte, (b58sz+3)*3)
- bytesleft = b58sz % 4
-
- zero = rune(alphabet.encode[0])
- )
-
- if bytesleft > 0 {
- zmask = (0xffffffff << uint32(bytesleft*8))
- } else {
- bytesleft = 4
- }
-
- var outi = make([]uint32, outisz)
-
- for i := 0; i < b58sz && b58u[i] == zero; i++ {
- zcount++
- }
-
- for _, r := range b58u {
- if r > 127 {
- return nil, fmt.Errorf("High-bit set on invalid digit")
- }
- if alphabet.decode[r] == -1 {
- return nil, fmt.Errorf("Invalid base58 digit (%q)", r)
- }
-
- c = uint32(alphabet.decode[r])
-
- for j := (outisz - 1); j >= 0; j-- {
- t = uint64(outi[j])*58 + uint64(c)
- c = uint32(t>>32) & 0x3f
- outi[j] = uint32(t & 0xffffffff)
- }
-
- if c > 0 {
- return nil, fmt.Errorf("Output number too big (carry to the next int32)")
- }
-
- if outi[0]&zmask != 0 {
- return nil, fmt.Errorf("Output number too big (last int32 filled too far)")
- }
- }
-
- // the nested for-loop below is the same as the original code:
- // switch (bytesleft) {
- // case 3:
- // *(binu++) = (outi[0] & 0xff0000) >> 16;
- // //-fallthrough
- // case 2:
- // *(binu++) = (outi[0] & 0xff00) >> 8;
- // //-fallthrough
- // case 1:
- // *(binu++) = (outi[0] & 0xff);
- // ++j;
- // //-fallthrough
- // default:
- // break;
- // }
- //
- // for (; j < outisz; ++j)
- // {
- // *(binu++) = (outi[j] >> 0x18) & 0xff;
- // *(binu++) = (outi[j] >> 0x10) & 0xff;
- // *(binu++) = (outi[j] >> 8) & 0xff;
- // *(binu++) = (outi[j] >> 0) & 0xff;
- // }
- var j, cnt int
- for j, cnt = 0, 0; j < outisz; j++ {
- for mask := byte(bytesleft-1) * 8; mask <= 0x18; mask, cnt = mask-8, cnt+1 {
- binu[cnt] = byte(outi[j] >> mask)
- }
- if j == 0 {
- bytesleft = 4 // because it could be less than 4 the first time through
- }
- }
-
- for n, v := range binu {
- if v > 0 {
- start := n - zcount
- if start < 0 {
- start = 0
- }
- return binu[start:cnt], nil
- }
- }
- return binu[:cnt], nil
-}
-
-// 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
-}
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