first commit

2023-10-24 17:35:33 -01:00
commit f47462a114
11 changed files with 658 additions and 0 deletions
--- a/README.md
+++ b/README.md
@@ -0,0 +1,13 @@
+base58
+==========
+
+Package base58 provides an API for encoding and decoding to and from the
+modified base58 encoding.  It also provides an API to do Base58Check encoding,
+as described [here](https://en.bitcoin.it/wiki/Base58Check_encoding).
+
+A comprehensive suite of tests is provided to ensure proper functionality.
+
+## License
+
+Package base58 is licensed under the [copyfree](http://copyfree.org) ISC
+License.
--- a/alphabet.go
+++ b/alphabet.go
@@ -0,0 +1,49 @@
+// Copyright (c) 2015 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+// AUTOGENERATED by genalphabet.go; do not edit.
+
+package base58
+
+const (
+	// alphabet is the modified base58 alphabet used by Bitcoin.
+	alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
+
+	alphabetIdx0 = '1'
+)
+
+var b58 = [256]byte{
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 0, 1, 2, 3, 4, 5, 6,
+	7, 8, 255, 255, 255, 255, 255, 255,
+	255, 9, 10, 11, 12, 13, 14, 15,
+	16, 255, 17, 18, 19, 20, 21, 255,
+	22, 23, 24, 25, 26, 27, 28, 29,
+	30, 31, 32, 255, 255, 255, 255, 255,
+	255, 33, 34, 35, 36, 37, 38, 39,
+	40, 41, 42, 43, 255, 44, 45, 46,
+	47, 48, 49, 50, 51, 52, 53, 54,
+	55, 56, 57, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255,
+}
--- a/base58.go
+++ b/base58.go
@@ -0,0 +1,142 @@
+// Copyright (c) 2013-2015 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package base58
+
+import (
+	"math/big"
+)
+
+//go:generate go run genalphabet.go
+
+var 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,
+}
+
+var bigRadix10 = big.NewInt(58 * 58 * 58 * 58 * 58 * 58 * 58 * 58 * 58 * 58) // 58^10
+
+// Decode decodes a modified base58 string to a byte slice.
+func Decode(b string) []byte {
+	answer := big.NewInt(0)
+	scratch := new(big.Int)
+
+	// Calculating with big.Int is slow for each iteration.
+	//    x += b58[b[i]] * j
+	//    j *= 58
+	//
+	// Instead we can try to do as much calculations on int64.
+	// We can represent a 10 digit base58 number using an int64.
+	//
+	// Hence we'll try to convert 10, base58 digits at a time.
+	// The rough idea is to calculate `t`, such that:
+	//
+	//   t := b58[b[i+9]] * 58^9 ... + b58[b[i+1]] * 58^1 + b58[b[i]] * 58^0
+	//   x *= 58^10
+	//   x += t
+	//
+	// Of course, in addition, we'll need to handle boundary condition when `b` is not multiple of 58^10.
+	// In that case we'll use the bigRadix[n] lookup for the appropriate power.
+	for t := b; len(t) > 0; {
+		n := len(t)
+		if n > 10 {
+			n = 10
+		}
+
+		total := uint64(0)
+		for _, v := range t[:n] {
+			if v > 255 {
+				return []byte("")
+			}
+
+			tmp := b58[v]
+			if tmp == 255 {
+				return []byte("")
+			}
+			total = total*58 + uint64(tmp)
+		}
+
+		answer.Mul(answer, bigRadix[n])
+		scratch.SetUint64(total)
+		answer.Add(answer, scratch)
+
+		t = t[n:]
+	}
+
+	tmpval := answer.Bytes()
+
+	var numZeros int
+	for numZeros = 0; numZeros < len(b); numZeros++ {
+		if b[numZeros] != alphabetIdx0 {
+			break
+		}
+	}
+	flen := numZeros + len(tmpval)
+	val := make([]byte, flen)
+	copy(val[numZeros:], tmpval)
+
+	return val
+}
+
+// Encode encodes a byte slice to a modified base58 string.
+func Encode(b []byte) string {
+	x := new(big.Int)
+	x.SetBytes(b)
+
+	// maximum length of output is log58(2^(8*len(b))) == len(b) * 8 / log(58)
+	maxlen := int(float64(len(b))*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, 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, alphabet[m%58])
+				m /= 58
+			}
+		} else {
+			m := mod.Int64()
+			for i := 0; i < 10; i++ {
+				answer = append(answer, alphabet[m%58])
+				m /= 58
+			}
+		}
+	}
+
+	// leading zero bytes
+	for _, i := range b {
+		if i != 0 {
+			break
+		}
+		answer = append(answer, 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 string(answer)
+}
--- a/base58_test.go
+++ b/base58_test.go
@@ -0,0 +1,103 @@
+// Copyright (c) 2013-2017 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package base58_test
+
+import (
+	"bytes"
+	"encoding/hex"
+	"testing"
+
+	"github.com/mleku/base58"
+)
+
+var stringTests = []struct {
+	in  string
+	out string
+}{
+	{"", ""},
+	{" ", "Z"},
+	{"-", "n"},
+	{"0", "q"},
+	{"1", "r"},
+	{"-1", "4SU"},
+	{"11", "4k8"},
+	{"abc", "ZiCa"},
+	{"1234598760", "3mJr7AoUXx2Wqd"},
+	{"abcdefghijklmnopqrstuvwxyz", "3yxU3u1igY8WkgtjK92fbJQCd4BZiiT1v25f"},
+	{"00000000000000000000000000000000000000000000000000000000000000", "3sN2THZeE9Eh9eYrwkvZqNstbHGvrxSAM7gXUXvyFQP8XvQLUqNCS27icwUeDT7ckHm4FUHM2mTVh1vbLmk7y"},
+}
+
+var invalidStringTests = []struct {
+	in  string
+	out string
+}{
+	{"0", ""},
+	{"O", ""},
+	{"I", ""},
+	{"l", ""},
+	{"3mJr0", ""},
+	{"O3yxU", ""},
+	{"3sNI", ""},
+	{"4kl8", ""},
+	{"0OIl", ""},
+	{"!@#$%^&*()-_=+~`", ""},
+	{"abcd\xd80", ""},
+	{"abcd\U000020BF", ""},
+}
+
+var hexTests = []struct {
+	in  string
+	out string
+}{
+	{"", ""},
+	{"61", "2g"},
+	{"626262", "a3gV"},
+	{"636363", "aPEr"},
+	{"73696d706c792061206c6f6e6720737472696e67", "2cFupjhnEsSn59qHXstmK2ffpLv2"},
+	{"00eb15231dfceb60925886b67d065299925915aeb172c06647", "1NS17iag9jJgTHD1VXjvLCEnZuQ3rJDE9L"},
+	{"516b6fcd0f", "ABnLTmg"},
+	{"bf4f89001e670274dd", "3SEo3LWLoPntC"},
+	{"572e4794", "3EFU7m"},
+	{"ecac89cad93923c02321", "EJDM8drfXA6uyA"},
+	{"10c8511e", "Rt5zm"},
+	{"00000000000000000000", "1111111111"},
+	{"000111d38e5fc9071ffcd20b4a763cc9ae4f252bb4e48fd66a835e252ada93ff480d6dd43dc62a641155a5", "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"},
+	{"000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f303132333435363738393a3b3c3d3e3f404142434445464748494a4b4c4d4e4f505152535455565758595a5b5c5d5e5f606162636465666768696a6b6c6d6e6f707172737475767778797a7b7c7d7e7f808182838485868788898a8b8c8d8e8f909192939495969798999a9b9c9d9e9fa0a1a2a3a4a5a6a7a8a9aaabacadaeafb0b1b2b3b4b5b6b7b8b9babbbcbdbebfc0c1c2c3c4c5c6c7c8c9cacbcccdcecfd0d1d2d3d4d5d6d7d8d9dadbdcdddedfe0e1e2e3e4e5e6e7e8e9eaebecedeeeff0f1f2f3f4f5f6f7f8f9fafbfcfdfeff", "1cWB5HCBdLjAuqGGReWE3R3CguuwSjw6RHn39s2yuDRTS5NsBgNiFpWgAnEx6VQi8csexkgYw3mdYrMHr8x9i7aEwP8kZ7vccXWqKDvGv3u1GxFKPuAkn8JCPPGDMf3vMMnbzm6Nh9zh1gcNsMvH3ZNLmP5fSG6DGbbi2tuwMWPthr4boWwCxf7ewSgNQeacyozhKDDQQ1qL5fQFUW52QKUZDZ5fw3KXNQJMcNTcaB723LchjeKun7MuGW5qyCBZYzA1KjofN1gYBV3NqyhQJ3Ns746GNuf9N2pQPmHz4xpnSrrfCvy6TVVz5d4PdrjeshsWQwpZsZGzvbdAdN8MKV5QsBDY"},
+}
+
+func TestBase58(t *testing.T) {
+	// Encode tests
+	for x, test := range stringTests {
+		tmp := []byte(test.in)
+		if res := base58.Encode(tmp); res != test.out {
+			t.Errorf("Encode test #%d failed: got: %s want: %s",
+				x, res, test.out)
+			continue
+		}
+	}
+
+	// Decode tests
+	for x, test := range hexTests {
+		b, err := hex.DecodeString(test.in)
+		if err != nil {
+			t.Errorf("hex.DecodeString failed failed #%d: got: %s", x, test.in)
+			continue
+		}
+		if res := base58.Decode(test.out); !bytes.Equal(res, b) {
+			t.Errorf("Decode test #%d failed: got: %q want: %q",
+				x, res, test.in)
+			continue
+		}
+	}
+
+	// Decode with invalid input
+	for x, test := range invalidStringTests {
+		if res := base58.Decode(test.in); string(res) != test.out {
+			t.Errorf("Decode invalidString test #%d failed: got: %q want: %q",
+				x, res, test.out)
+			continue
+		}
+	}
+}
--- a/base58bench_test.go
+++ b/base58bench_test.go
@@ -0,0 +1,47 @@
+// Copyright (c) 2013-2014 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package base58_test
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/mleku/base58"
+)
+
+var (
+	raw5k       = bytes.Repeat([]byte{0xff}, 5000)
+	raw100k     = bytes.Repeat([]byte{0xff}, 100*1000)
+	encoded5k   = base58.Encode(raw5k)
+	encoded100k = base58.Encode(raw100k)
+)
+
+func BenchmarkBase58Encode_5K(b *testing.B) {
+	b.SetBytes(int64(len(raw5k)))
+	for i := 0; i < b.N; i++ {
+		base58.Encode(raw5k)
+	}
+}
+
+func BenchmarkBase58Encode_100K(b *testing.B) {
+	b.SetBytes(int64(len(raw100k)))
+	for i := 0; i < b.N; i++ {
+		base58.Encode(raw100k)
+	}
+}
+
+func BenchmarkBase58Decode_5K(b *testing.B) {
+	b.SetBytes(int64(len(encoded5k)))
+	for i := 0; i < b.N; i++ {
+		base58.Decode(encoded5k)
+	}
+}
+
+func BenchmarkBase58Decode_100K(b *testing.B) {
+	b.SetBytes(int64(len(encoded100k)))
+	for i := 0; i < b.N; i++ {
+		base58.Decode(encoded100k)
+	}
+}
--- a/base58check.go
+++ b/base58check.go
@@ -0,0 +1,52 @@
+// Copyright (c) 2013-2014 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package base58
+
+import (
+	"crypto/sha256"
+	"errors"
+)
+
+// ErrChecksum indicates that the checksum of a check-encoded string does not verify against
+// the checksum.
+var ErrChecksum = errors.New("checksum error")
+
+// ErrInvalidFormat indicates that the check-encoded string has an invalid format.
+var ErrInvalidFormat = errors.New("invalid format: version and/or checksum bytes missing")
+
+// checksum: first four bytes of sha256^2
+func checksum(input []byte) (cksum [4]byte) {
+	h := sha256.Sum256(input)
+	h2 := sha256.Sum256(h[:])
+	copy(cksum[:], h2[:4])
+	return
+}
+
+// CheckEncode prepends a version byte and appends a four byte checksum.
+func CheckEncode(input []byte, version byte) string {
+	b := make([]byte, 0, 1+len(input)+4)
+	b = append(b, version)
+	b = append(b, input...)
+	cksum := checksum(b)
+	b = append(b, cksum[:]...)
+	return Encode(b)
+}
+
+// CheckDecode decodes a string that was encoded with CheckEncode and verifies the checksum.
+func CheckDecode(input string) (result []byte, version byte, err error) {
+	decoded := Decode(input)
+	if len(decoded) < 5 {
+		return nil, 0, ErrInvalidFormat
+	}
+	version = decoded[0]
+	var cksum [4]byte
+	copy(cksum[:], decoded[len(decoded)-4:])
+	if checksum(decoded[:len(decoded)-4]) != cksum {
+		return nil, 0, ErrChecksum
+	}
+	payload := decoded[1 : len(decoded)-4]
+	result = append(result, payload...)
+	return
+}
--- a/base58check_test.go
+++ b/base58check_test.go
@@ -0,0 +1,69 @@
+// Copyright (c) 2013-2014 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package base58_test
+
+import (
+	"testing"
+
+	"github.com/mleku/base58"
+)
+
+var checkEncodingStringTests = []struct {
+	version byte
+	in      string
+	out     string
+}{
+	{20, "", "3MNQE1X"},
+	{20, " ", "B2Kr6dBE"},
+	{20, "-", "B3jv1Aft"},
+	{20, "0", "B482yuaX"},
+	{20, "1", "B4CmeGAC"},
+	{20, "-1", "mM7eUf6kB"},
+	{20, "11", "mP7BMTDVH"},
+	{20, "abc", "4QiVtDjUdeq"},
+	{20, "1234598760", "ZmNb8uQn5zvnUohNCEPP"},
+	{20, "abcdefghijklmnopqrstuvwxyz", "K2RYDcKfupxwXdWhSAxQPCeiULntKm63UXyx5MvEH2"},
+	{20, "00000000000000000000000000000000000000000000000000000000000000", "bi1EWXwJay2udZVxLJozuTb8Meg4W9c6xnmJaRDjg6pri5MBAxb9XwrpQXbtnqEoRV5U2pixnFfwyXC8tRAVC8XxnjK"},
+}
+
+func TestBase58Check(t *testing.T) {
+	for x, test := range checkEncodingStringTests {
+		// test encoding
+		if res := base58.CheckEncode([]byte(test.in), test.version); res != test.out {
+			t.Errorf("CheckEncode test #%d failed: got %s, want: %s", x, res, test.out)
+		}
+
+		// test decoding
+		res, version, err := base58.CheckDecode(test.out)
+		switch {
+		case err != nil:
+			t.Errorf("CheckDecode test #%d failed with err: %v", x, err)
+
+		case version != test.version:
+			t.Errorf("CheckDecode test #%d failed: got version: %d want: %d", x, version, test.version)
+
+		case string(res) != test.in:
+			t.Errorf("CheckDecode test #%d failed: got: %s want: %s", x, res, test.in)
+		}
+	}
+
+	// test the two decoding failure cases
+	// case 1: checksum error
+	_, _, err := base58.CheckDecode("3MNQE1Y")
+	if err != base58.ErrChecksum {
+		t.Error("Checkdecode test failed, expected ErrChecksum")
+	}
+	// case 2: invalid formats (string lengths below 5 mean the version byte and/or the checksum
+	// bytes are missing).
+	testString := ""
+	for len := 0; len < 4; len++ {
+		testString += "x"
+		_, _, err = base58.CheckDecode(testString)
+		if err != base58.ErrInvalidFormat {
+			t.Error("Checkdecode test failed, expected ErrInvalidFormat")
+		}
+	}
+
+}
--- a/doc.go
+++ b/doc.go
@@ -0,0 +1,29 @@
+// Copyright (c) 2014 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+/*
+Package base58 provides an API for working with modified base58 and Base58Check
+encodings.
+
+# Modified Base58 Encoding
+
+Standard base58 encoding is similar to standard base64 encoding except, as the
+name implies, it uses a 58 character alphabet which results in an alphanumeric
+string and allows some characters which are problematic for humans to be
+excluded.  Due to this, there can be various base58 alphabets.
+
+The modified base58 alphabet used by Bitcoin, and hence this package, omits the
+0, O, I, and l characters that look the same in many fonts and are therefore
+hard to humans to distinguish.
+
+# Base58Check Encoding Scheme
+
+The Base58Check encoding scheme is primarily used for Bitcoin addresses at the
+time of this writing, however it can be used to generically encode arbitrary
+byte arrays into human-readable strings along with a version byte that can be
+used to differentiate the same payload.  For Bitcoin addresses, the extra
+version is used to differentiate the network of otherwise identical public keys
+which helps prevent using an address intended for one network on another.
+*/
+package base58
--- a/example_test.go
+++ b/example_test.go
@@ -0,0 +1,71 @@
+// Copyright (c) 2014 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package base58_test
+
+import (
+	"fmt"
+
+	"github.com/mleku/base58"
+)
+
+// This example demonstrates how to decode modified base58 encoded data.
+func ExampleDecode() {
+	// Decode example modified base58 encoded data.
+	encoded := "25JnwSn7XKfNQ"
+	decoded := base58.Decode(encoded)
+
+	// Show the decoded data.
+	fmt.Println("Decoded Data:", string(decoded))
+
+	// Output:
+	// Decoded Data: Test data
+}
+
+// This example demonstrates how to encode data using the modified base58
+// encoding scheme.
+func ExampleEncode() {
+	// Encode example data with the modified base58 encoding scheme.
+	data := []byte("Test data")
+	encoded := base58.Encode(data)
+
+	// Show the encoded data.
+	fmt.Println("Encoded Data:", encoded)
+
+	// Output:
+	// Encoded Data: 25JnwSn7XKfNQ
+}
+
+// This example demonstrates how to decode Base58Check encoded data.
+func ExampleCheckDecode() {
+	// Decode an example Base58Check encoded data.
+	encoded := "1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa"
+	decoded, version, err := base58.CheckDecode(encoded)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	// Show the decoded data.
+	fmt.Printf("Decoded data: %x\n", decoded)
+	fmt.Println("Version Byte:", version)
+
+	// Output:
+	// Decoded data: 62e907b15cbf27d5425399ebf6f0fb50ebb88f18
+	// Version Byte: 0
+}
+
+// This example demonstrates how to encode data using the Base58Check encoding
+// scheme.
+func ExampleCheckEncode() {
+	// Encode example data with the Base58Check encoding scheme.
+	data := []byte("Test data")
+	encoded := base58.CheckEncode(data, 0)
+
+	// Show the encoded data.
+	fmt.Println("Encoded Data:", encoded)
+
+	// Output:
+	// Encoded Data: 182iP79GRURMp7oMHDU
+}
--- a/genalphabet.go
+++ b/genalphabet.go
@@ -0,0 +1,80 @@
+// Copyright (c) 2015 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+//go:build ignore
+// +build ignore
+
+package main
+
+import (
+	"bytes"
+	"io"
+	"log"
+	"os"
+	"strconv"
+)
+
+var (
+	start = []byte(`// Copyright (c) 2015 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+// AUTOGENERATED by genalphabet.go; do not edit.
+
+package base58
+
+const (
+	// alphabet is the modified base58 alphabet used by Bitcoin.
+	alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
+
+	alphabetIdx0 = '1'
+)
+
+var b58 = [256]byte{`)
+
+	end = []byte(`}`)
+
+	alphabet = []byte("123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz")
+	tab      = []byte("\t")
+	invalid  = []byte("255")
+	comma    = []byte(",")
+	space    = []byte(" ")
+	nl       = []byte("\n")
+)
+
+func write(w io.Writer, b []byte) {
+	_, err := w.Write(b)
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
+func main() {
+	fi, err := os.Create("alphabet.go")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer fi.Close()
+
+	write(fi, start)
+	write(fi, nl)
+	for i := byte(0); i < 32; i++ {
+		write(fi, tab)
+		for j := byte(0); j < 8; j++ {
+			idx := bytes.IndexByte(alphabet, i*8+j)
+			if idx == -1 {
+				write(fi, invalid)
+			} else {
+				write(fi, strconv.AppendInt(nil, int64(idx), 10))
+			}
+			write(fi, comma)
+			if j != 7 {
+				write(fi, space)
+			}
+		}
+		write(fi, nl)
+	}
+	write(fi, end)
+	write(fi, nl)
+}
--- a/go.mod
+++ b/go.mod
@@ -0,0 +1,3 @@
+module github.com/mleku/base58
+
+go 1.20