encoding: add base58 support (#11288)

vlib/encoding/base58/base58_test.v

@@ -0,0 +1,89 @@
+module base58
+
+fn main() {
+	test_encode_int() or {}
+	test_decode_int() or {}
+	test_encode_string()
+	test_fails() or {}
+}
+
+fn test_encode_int() ? {
+	a := 0x24 // should be 'd' in base58
+	assert encode_int(a) ? == 'd'
+
+	test_encode_int_walpha() ?
+}
+
+fn test_encode_int_walpha() ? {
+	// random alphabet
+	abc := new_alphabet('abcdefghij\$lmnopqrstuvwxyz0123456789_ABCDEFGHIJLMNOPQRSTUV') or {
+		panic(@MOD + '.' + @FN + ': this should never happen')
+	}
+	a := 0x24 // should be '_' in base58 with our custom alphabet
+	assert encode_int_walpha(a, abc) ? == '_'
+}
+
+fn test_decode_int() ? {
+	a := 'd'
+	assert decode_int(a) ? == 0x24
+
+	test_decode_int_walpha() ?
+}
+
+fn test_decode_int_walpha() ? {
+	abc := new_alphabet('abcdefghij\$lmnopqrstuvwxyz0123456789_ABCDEFGHIJLMNOPQRSTUV') or {
+		panic(@MOD + '.' + @FN + ': this should never happen')
+	}
+	a := '_'
+	assert decode_int_walpha(a, abc) ? == 0x24
+}
+
+fn test_encode_string() {
+	// should be 'TtaR6twpTGu8VpY' in base58 and '0P7yfPSL0pQh2L5' with our custom alphabet
+	a := 'lorem ipsum'
+	assert encode(a) == 'TtaR6twpTGu8VpY'
+
+	abc := new_alphabet('abcdefghij\$lmnopqrstuvwxyz0123456789_ABCDEFGHIJLMNOPQRSTUV') or {
+		panic(@MOD + '.' + @FN + ': this should never happen')
+	}
+	assert encode_walpha(a, abc) == '0P7yfPSL0pQh2L5'
+}
+
+fn test_decode_string() ? {
+	a := 'TtaR6twpTGu8VpY'
+	assert decode(a) ? == 'lorem ipsum'
+
+	abc := new_alphabet('abcdefghij\$lmnopqrstuvwxyz0123456789_ABCDEFGHIJLMNOPQRSTUV') or {
+		panic(@MOD + '.' + @FN + ': this should never happen')
+	}
+	b := '0P7yfPSL0pQh2L5'
+	assert decode_walpha(b, abc) ? == 'lorem ipsum'
+}
+
+fn test_fails() ? {
+	a := -238
+	b := 0
+	if z := encode_int(a) {
+		return error(@MOD + '.' + @FN + ': expected encode_int to fail, got $z')
+	}
+	if z := encode_int(b) {
+		return error(@MOD + '.' + @FN + ': expected encode_int to fail, got $z')
+	}
+
+	c := '!'
+	if z := decode_int(c) {
+		return error(@MOD + '.' + @FN + ': expected decode_int to fail, got $z')
+	}
+	if z := decode(c) {
+		return error(@MOD + '.' + @FN + ': expected decode to fail, got $z')
+	}
+
+	// repeating character
+	if abc := new_alphabet('aaaaafghij\$lmnopqrstuvwxyz0123456789_ABCDEFGHIJLMNOPQRSTUV') {
+		return error(@MOD + '.' + @FN + ': expected new_alphabet to fail, got $abc')
+	}
+	// more than 58 characters long
+	if abc := new_alphabet('abcdefghij\$lmnopqrstuvwxyz0123456789_ABCDEFGHIJLMNOPQRSTUVWXYZ') {
+		return error(@MOD + '.' + @FN + ': expected new_alphabet to fail, got $abc')
+	}
+}