base58: refactor and doc (#7)

src/base58/alphabet.zig

@@ -114,7 +114,7 @@ pub const Alphabet = struct {
  i += 1;
  }
 
- return Self{
+ return .{
  .encode = encode,
  .decode = decode,
  };

src/base58/decode.zig

@@ -26,6 +26,8 @@ pub const Decoder = struct {
 
  /// Pass a `encoded` and a `dest` to write decoded value into. `decode` returns a
  /// `usize` indicating how many bytes were written. Sizing/resizing, `dest` buffer is up to the caller.
+ ///
+ /// For further information on the Base58 decoding algorithm, see: https://datatracker.ietf.org/doc/html/draft-msporny-base58-03
  pub fn decode(self: *const Self, encoded: []const u8, dest: []u8) !usize {
  var index: usize = 0;
  const zero = self.alpha.encode[0];
@@ -44,7 +46,7 @@ pub const Decoder = struct {
  while (x < index) : (x += 1) {
  const byte = &dest[x];
  val += @as(usize, @intCast(byte.*)) * 58;
- byte.* = @as(u8, @intCast(val & 0xFF));
+ byte.* = @intCast(val & 0xFF);
  val >>= 8;
  }
 
@@ -53,21 +55,17 @@ pub const Decoder = struct {
  return error.BufferTooSmall;
  }
 
- const byte = &dest[index];
- byte.* = @as(u8, @intCast(val)) & 0xFF;
+ dest[index] = @as(u8, @intCast(val)) & 0xFF;
  index += 1;
  val >>= 8;
  }
  }
 
- for (encoded) |*c| {
- if (c.* == zero) {
- const byte = &dest[index];
- byte.* = 0;
- index += 1;
- } else {
- break;
- }
+ for (encoded) |c| {
+ if (c != zero) break;
+
+ dest[index] = 0;
+ index += 1;
  }
 
  std.mem.reverse(u8, dest[0..index]);
@@ -94,11 +92,8 @@ pub const Decoder = struct {
  hasher = std.crypto.hash.sha2.Sha256.init(.{});
  hasher.update(&fr);
 
- const hash_check = hasher.finalResult()[0..4].*;
- const data_check = decoded[check_start..][0..4].*;
-
- const expected = std.mem.readInt(u32, &hash_check, .little);
- const actual = std.mem.readInt(u32, &data_check, .little);
+ const expected = std.mem.readInt(u32, hasher.finalResult()[0..4], .little);
+ const actual = std.mem.readInt(u32, decoded[check_start..][0..4], .little);
 
  if (expected != actual) return error.IncorrectChecksum;