# std/codecs

Hex, base64 and percent encoding over UTF-8 bytes. These are the `hexEncode`, `hexDecode`, `base64Encode`, `base64Decode`, `urlEncode` and `urlDecode` builtins on every engine; `tests/codecs.rs` pins their output.

A decoder whose bytes contain `0x00` returns `None`: a Vyrn `String` cannot hold a NUL, and `stringFromBytes` enforces it.

## hexEncode

`fn`, at line 55.

```vyrn
fn hexEncode(s: String) -> String
```

A string's UTF-8 bytes as lowercase hex, two digits per byte.

## hexDecode

`fn`, at line 69.

```vyrn
fn hexDecode(s: String) -> Option<String>
```

Hex text back to a `String`; `None` on an odd length, a non-hex digit, or bytes that are not valid UTF-8. Reads either case.

## base64Encode

`fn`, at line 113.

```vyrn
fn base64Encode(s: String) -> String
```

## base64EncodeBytes

`fn`, at line 118.

```vyrn
fn base64EncodeBytes(b: Array<UInt8>) -> String
```

Base64 of bytes that are not text, such as a digest: they can hold a NUL and need not be UTF-8.

## base64Decode

`fn`, at line 152.

```vyrn
fn base64Decode(s: String) -> Option<String>
```

Base64 text back to a `String`; `None` unless the length is a multiple of four, every digit is in the alphabet, padding is `=` or `==` in the final group only, and the bytes are valid UTF-8.

## urlEncode

`fn`, at line 205.

```vyrn
fn urlEncode(s: String) -> String
```

A string's UTF-8 bytes percent-encoded, uppercase hex.

## urlDecode

`fn`, at line 224.

```vyrn
fn urlDecode(s: String) -> Option<String>
```

Percent-encoded text back to a `String`; `None` on a truncated or non-hex escape, or bytes that are not valid UTF-8. A raw space or `+` decodes to itself.

---

From https://vyrn-lang.github.io/docs/std/codecs.html — generated by `site/export.vyrn` from the Vyrn repository.