base58

_data/version.sh

@@ -32,7 +32,13 @@ echo ""
 
 git add --verbose .
 
-git commit -a -m "v${next_ver}"
+msg="v${next_ver}"
+
+if [ $# -gt 0 ]; then
+  msg="$1"
+fi
+
+git commit -a -m "${msg}"
 
 git tag "v${next_ver}"
 

langext/base58.go

@@ -0,0 +1,178 @@
+package langext
+
+import (
+	"bytes"
+	"errors"
+	"math/big"
+)
+
+// shamelessly stolen from https://github.com/btcsuite/
+
+type B58Encoding struct {
+	bigRadix     [11]*big.Int
+	bigRadix10   *big.Int
+	alphabet     string
+	alphabetIdx0 byte
+	b58          [256]byte
+}
+
+var Base58DefaultEncoding = newBase58Encoding("123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz")
+var Base58FlickrEncoding = newBase58Encoding("123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ")
+var Base58RippleEncoding = newBase58Encoding("rpshnaf39wBUDNEGHJKLM4PQRST7VWXYZ2bcdeCg65jkm8oFqi1tuvAxyz")
+var Base58BitcoinEncoding = newBase58Encoding("123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz")
+
+func newBase58Encoding(alphabet string) *B58Encoding {
+	bigRadix10 := big.NewInt(58 * 58 * 58 * 58 * 58 * 58 * 58 * 58 * 58 * 58)
+	enc := &B58Encoding{
+		alphabet:     alphabet,
+		alphabetIdx0: '1',
+		bigRadix: [...]*big.Int{
+			big.NewInt(0),
+			big.NewInt(58),
+			big.NewInt(58 * 58),
+			big.NewInt(58 * 58 * 58),
+			big.NewInt(58 * 58 * 58 * 58),
+			big.NewInt(58 * 58 * 58 * 58 * 58),
+			big.NewInt(58 * 58 * 58 * 58 * 58 * 58),
+			big.NewInt(58 * 58 * 58 * 58 * 58 * 58 * 58),
+			big.NewInt(58 * 58 * 58 * 58 * 58 * 58 * 58 * 58),
+			big.NewInt(58 * 58 * 58 * 58 * 58 * 58 * 58 * 58 * 58),
+			bigRadix10,
+		},
+		bigRadix10: bigRadix10,
+	}
+
+	b58 := make([]byte, 0, 256)
+
+	for i := byte(0); i < 32; i++ {
+		for j := byte(0); j < 8; j++ {
+
+			b := i*8 + j
+
+			idx := bytes.IndexByte([]byte(alphabet), b)
+			if idx == -1 {
+				b58 = append(b58, 255)
+			} else {
+				b58 = append(b58, byte(idx))
+			}
+
+		}
+	}
+
+	enc.b58 = *((*[256]byte)(b58))
+
+	return enc
+}
+
+func (enc *B58Encoding) EncodeString(src string) (string, error) {
+	v, err := enc.Encode([]byte(src))
+	if err != nil {
+		return "", err
+	}
+	return string(v), nil
+}
+
+func (enc *B58Encoding) Encode(src []byte) ([]byte, error) {
+	x := new(big.Int)
+	x.SetBytes(src)
+
+	// maximum length of output is log58(2^(8*len(b))) == len(b) * 8 / log(58)
+	maxlen := int(float64(len(src))*1.365658237309761) + 1
+	answer := make([]byte, 0, maxlen)
+	mod := new(big.Int)
+	for x.Sign() > 0 {
+		// Calculating with big.Int is slow for each iteration.
+		//    x, mod = x / 58, x % 58
+		//
+		// Instead we can try to do as much calculations on int64.
+		//    x, mod = x / 58^10, x % 58^10
+		//
+		// Which will give us mod, which is 10 digit base58 number.
+		// We'll loop that 10 times to convert to the answer.
+
+		x.DivMod(x, enc.bigRadix10, mod)
+		if x.Sign() == 0 {
+			// When x = 0, we need to ensure we don't add any extra zeros.
+			m := mod.Int64()
+			for m > 0 {
+				answer = append(answer, enc.alphabet[m%58])
+				m /= 58
+			}
+		} else {
+			m := mod.Int64()
+			for i := 0; i < 10; i++ {
+				answer = append(answer, enc.alphabet[m%58])
+				m /= 58
+			}
+		}
+	}
+
+	// leading zero bytes
+	for _, i := range src {
+		if i != 0 {
+			break
+		}
+		answer = append(answer, enc.alphabetIdx0)
+	}
+
+	// reverse
+	alen := len(answer)
+	for i := 0; i < alen/2; i++ {
+		answer[i], answer[alen-1-i] = answer[alen-1-i], answer[i]
+	}
+
+	return answer, nil
+}
+
+func (enc *B58Encoding) DecodeString(src string) (string, error) {
+	v, err := enc.Decode([]byte(src))
+	if err != nil {
+		return "", err
+	}
+	return string(v), nil
+}
+
+func (enc *B58Encoding) Decode(src []byte) ([]byte, error) {
+	answer := big.NewInt(0)
+	scratch := new(big.Int)
+
+	for t := src; len(t) > 0; {
+		n := len(t)
+		if n > 10 {
+			n = 10
+		}
+
+		total := uint64(0)
+		for _, v := range t[:n] {
+			if v > 255 {
+				return []byte{}, errors.New("invalid char in input")
+			}
+
+			tmp := enc.b58[v]
+			if tmp == 255 {
+				return []byte{}, errors.New("invalid char in input")
+			}
+			total = total*58 + uint64(tmp)
+		}
+
+		answer.Mul(answer, enc.bigRadix[n])
+		scratch.SetUint64(total)
+		answer.Add(answer, scratch)
+
+		t = t[n:]
+	}
+
+	tmpval := answer.Bytes()
+
+	var numZeros int
+	for numZeros = 0; numZeros < len(src); numZeros++ {
+		if src[numZeros] != enc.alphabetIdx0 {
+			break
+		}
+	}
+	flen := numZeros + len(tmpval)
+	val := make([]byte, flen)
+	copy(val[numZeros:], tmpval)
+
+	return val, nil
+}

langext/base58_test.go

@@ -0,0 +1,67 @@
+package langext
+
+import (
+	"testing"
+)
+
+func _encStr(t *testing.T, enc *B58Encoding, v string) string {
+	v, err := enc.EncodeString(v)
+	if err != nil {
+		t.Error(err)
+	}
+	return v
+}
+
+func _decStr(t *testing.T, enc *B58Encoding, v string) string {
+	v, err := enc.DecodeString(v)
+	if err != nil {
+		t.Error(err)
+	}
+	return v
+}
+
+func TestBase58DefaultEncoding(t *testing.T) {
+	assertEqual(t, _encStr(t, Base58DefaultEncoding, "Hello"), "9Ajdvzr")
+	assertEqual(t, _encStr(t, Base58DefaultEncoding, "If debugging is the process of removing software bugs, then programming must be the process of putting them in."), "48638SMcJuah5okqPx4kCVf5d8QAdgbdNf28g7ReY13prUENNbMyssjq5GjsrJHF5zeZfqs4uJMUJHr7VbrU4XBUZ2Fw9DVtqtn9N1eXucEWSEZahXV6w4ysGSWqGdpeYTJf1MdDzTg8vfcQViifJjZX")
+}
+
+func TestBase58DefaultDecoding(t *testing.T) {
+	assertEqual(t, _decStr(t, Base58DefaultEncoding, "9Ajdvzr"), "Hello")
+	assertEqual(t, _decStr(t, Base58DefaultEncoding, "48638SMcJuah5okqPx4kCVf5d8QAdgbdNf28g7ReY13prUENNbMyssjq5GjsrJHF5zeZfqs4uJMUJHr7VbrU4XBUZ2Fw9DVtqtn9N1eXucEWSEZahXV6w4ysGSWqGdpeYTJf1MdDzTg8vfcQViifJjZX"), "If debugging is the process of removing software bugs, then programming must be the process of putting them in.")
+}
+
+func TestBase58RippleEncoding(t *testing.T) {
+	assertEqual(t, _encStr(t, Base58RippleEncoding, "Hello"), "9wjdvzi")
+	assertEqual(t, _encStr(t, Base58RippleEncoding, "If debugging is the process of removing software bugs, then programming must be the process of putting them in."), "h3as3SMcJu26nokqPxhkUVCnd3Qwdgbd4Cp3gfReYrsFi7N44bMy11jqnGj1iJHEnzeZCq1huJM7JHifVbi7hXB7ZpEA9DVtqt894reXucNWSNZ26XVaAhy1GSWqGdFeYTJCrMdDzTg3vCcQV55CJjZX")
+}
+
+func TestBase58RippleDecoding(t *testing.T) {
+	assertEqual(t, _decStr(t, Base58RippleEncoding, "9wjdvzi"), "Hello")
+	assertEqual(t, _decStr(t, Base58RippleEncoding, "h3as3SMcJu26nokqPxhkUVCnd3Qwdgbd4Cp3gfReYrsFi7N44bMy11jqnGj1iJHEnzeZCq1huJM7JHifVbi7hXB7ZpEA9DVtqt894reXucNWSNZ26XVaAhy1GSWqGdFeYTJCrMdDzTg3vCcQV55CJjZX"), "If debugging is the process of removing software bugs, then programming must be the process of putting them in.")
+}
+
+func TestBase58BitcoinEncoding(t *testing.T) {
+	assertEqual(t, _encStr(t, Base58BitcoinEncoding, "Hello"), "9Ajdvzr")
+	assertEqual(t, _encStr(t, Base58BitcoinEncoding, "If debugging is the process of removing software bugs, then programming must be the process of putting them in."), "48638SMcJuah5okqPx4kCVf5d8QAdgbdNf28g7ReY13prUENNbMyssjq5GjsrJHF5zeZfqs4uJMUJHr7VbrU4XBUZ2Fw9DVtqtn9N1eXucEWSEZahXV6w4ysGSWqGdpeYTJf1MdDzTg8vfcQViifJjZX")
+}
+
+func TestBase58BitcoinDecoding(t *testing.T) {
+	assertEqual(t, _decStr(t, Base58BitcoinEncoding, "9Ajdvzr"), "Hello")
+	assertEqual(t, _decStr(t, Base58BitcoinEncoding, "48638SMcJuah5okqPx4kCVf5d8QAdgbdNf28g7ReY13prUENNbMyssjq5GjsrJHF5zeZfqs4uJMUJHr7VbrU4XBUZ2Fw9DVtqtn9N1eXucEWSEZahXV6w4ysGSWqGdpeYTJf1MdDzTg8vfcQViifJjZX"), "If debugging is the process of removing software bugs, then programming must be the process of putting them in.")
+}
+
+func TestBase58FlickrEncoding(t *testing.T) {
+	assertEqual(t, _encStr(t, Base58FlickrEncoding, "Hello"), "9aJCVZR")
+	assertEqual(t, _encStr(t, Base58FlickrEncoding, "If debugging is the process of removing software bugs, then programming must be the process of putting them in."), "48638rmBiUzG5NKQoX4KcuE5C8paCFACnE28F7qDx13PRtennAmYSSJQ5gJSRihf5ZDyEQS4UimtihR7uARt4wbty2fW9duTQTM9n1DwUBevreyzGwu6W4YSgrvQgCPDxsiE1mCdZsF8VEBpuHHEiJyw")
+}
+
+func TestBase58FlickrDecoding(t *testing.T) {
+	assertEqual(t, _decStr(t, Base58FlickrEncoding, "9aJCVZR"), "Hello")
+	assertEqual(t, _decStr(t, Base58FlickrEncoding, "48638rmBiUzG5NKQoX4KcuE5C8paCFACnE28F7qDx13PRtennAmYSSJQ5gJSRihf5ZDyEQS4UimtihR7uARt4wbty2fW9duTQTM9n1DwUBevreyzGwu6W4YSgrvQgCPDxsiE1mCdZsF8VEBpuHHEiJyw"), "If debugging is the process of removing software bugs, then programming must be the process of putting them in.")
+}
+
+func assertEqual(t *testing.T, actual string, expected string) {
+	if actual != expected {
+		t.Errorf("values differ: Actual: '%v', Expected: '%v'", actual, expected)
+	}
+}