gno.land/r/moul/x/daily/b58demo/v0⧉

1// Package b58demo is a small gnoweb demo of the Base58 codec provided by the2// [p/moul/x/daily/b58](/p/moul/x/daily/b58/v0) library: it renders the alphabet,3// a gallery of worked examples, and an interactive hex → Base58 round-tripper.4//5// It contains no codec logic of its own — everything comes from `b58.Encode`,6// `b58.Decode` and `b58.Alphabet`.7package b58demo89import (10	"encoding/hex"11	"strings"1213	"gno.land/p/moul/x/daily/b58/v0"14)1516// Render produces the gnoweb Markdown view.17//18//   - "/"        → the alphabet + a small gallery of worked examples.19//   - "/<hex>"   → decode the hex input to bytes, show its Base58, and the20//     hex-encoded decoded round-trip to prove Encode/Decode are inverse.21func Render(path string) string {22	arg := strings.TrimPrefix(path, "/")23	arg = strings.TrimSpace(arg)2425	if arg == "" {26		return renderHome()27	}28	return renderHex(arg)29}3031func renderHome() string {32	var sb strings.Builder33	sb.WriteString("# Base58 (Bitcoin alphabet)\n\n")34	sb.WriteString("Demo of the [`p/moul/x/daily/b58`](/p/moul/x/daily/b58/v0) library — ")35	sb.WriteString("base conversion from raw bytes (base-256) to base-58, using the ")36	sb.WriteString("Bitcoin alphabet (no `0`, `O`, `I`, `l`), pure byte-slice math, no `math/big`.\n\n")3738	sb.WriteString("## Alphabet\n\n")39	sb.WriteString("```\n")40	sb.WriteString(b58.Alphabet)41	sb.WriteString("\n```\n\n")42	sb.WriteString("58 characters, index 0…57.\n\n")4344	sb.WriteString("## Examples\n\n")45	sb.WriteString("| input (utf-8) | hex | Base58 |\n")46	sb.WriteString("|---|---|---|\n")47	examples := []string{"", "hello world", "gno.land", "Bitcoin"}48	for _, e := range examples {49		h := hex.EncodeToString([]byte(e))50		if h == "" {51			h = "(empty)"52		}53		label := e54		if label == "" {55			label = "(empty)"56		}57		sb.WriteString("| `" + label + "` | `" + h + "` | `" + b58.Encode([]byte(e)) + "` |\n")58	}59	sb.WriteString("\n")6061	sb.WriteString("Leading zero bytes → leading `1`s:\n\n")62	sb.WriteString("| bytes | Base58 |\n|---|---|\n")63	sb.WriteString("| `[0x00]` | `" + b58.Encode([]byte{0}) + "` |\n")64	sb.WriteString("| `[0x00 0x00 0x00]` | `" + b58.Encode([]byte{0, 0, 0}) + "` |\n\n")6566	sb.WriteString("## Try it\n\n")67	sb.WriteString("Append a hex string to the path to encode/round-trip it:\n\n")68	sb.WriteString("- `/68656c6c6f` — the bytes for \"hello\"\n")69	sb.WriteString("- `/00000000` — four zero bytes\n")70	sb.WriteString("- `/deadbeef`\n")71	return sb.String()72}7374func renderHex(arg string) string {75	var sb strings.Builder76	sb.WriteString("# Base58 — round-trip\n\n")77	sb.WriteString("[← alphabet & examples](/r/moul/x/daily/b58demo/v0)\n\n")7879	raw, err := hex.DecodeString(arg)80	if err != nil {81		sb.WriteString("**Invalid hex input.**\n\n")82		sb.WriteString("`" + arg + "` is not a valid hex string. ")83		sb.WriteString("Provide an even number of hex digits, e.g. `/deadbeef`.\n")84		return sb.String()85	}8687	encoded := b58.Encode(raw)88	decoded := b58.Decode(encoded)89	roundTrip := hex.EncodeToString(decoded)9091	inHex := arg92	if inHex == "" {93		inHex = "(empty)"94	}95	outHex := roundTrip96	if outHex == "" {97		outHex = "(empty)"98	}99	enc := encoded100	if enc == "" {101		enc = "(empty)"102	}103104	sb.WriteString("| step | value |\n|---|---|\n")105	sb.WriteString("| hex input | `" + inHex + "` |\n")106	sb.WriteString("| bytes | `" + byteList(raw) + "` |\n")107	sb.WriteString("| **Base58** | `" + enc + "` |\n")108	sb.WriteString("| decoded (hex) | `" + outHex + "` |\n\n")109110	if roundTrip == arg {111		sb.WriteString("✓ Round-trip matches: `Decode(Encode(x)) == x`.\n")112	} else {113		sb.WriteString("✗ Round-trip mismatch.\n")114	}115	return sb.String()116}117118// byteList renders a byte slice as a compact space-separated hex list.119func byteList(b []byte) string {120	if len(b) == 0 {121		return "(none)"122	}123	const digits = "0123456789abcdef"124	out := make([]byte, 0, len(b)*3)125	for i, c := range b {126		if i > 0 {127			out = append(out, ' ')128		}129		out = append(out, digits[c>>4], digits[c&0x0f])130	}131	return string(out)132}133