encoding::base64 +linux +x86_64

Implementation of the base64 encoding scheme as defined by RFC 4648.

A stream-based encoding and decoding interface is available via newencoder and newdecoder, which transparently encode or decode bytes to or from base64 when writing to or reading from an underlying I/O handle.

Convenience functions for encoding to or decoding from a byte slice or a string are also available; see encodeslice, decodeslice, encodestr, and decodestr. These functions dynamically allocate their return values; use the stream interface if you require static allocation.

Each function accepts the desired base64 encoding alphabet as its first argument. std_encoding and url_encoding, as defined by the RFC, are provided for your convenience, but you may create your own encoding using encoding_init.

Due to security concerns described by the RFC, this implementation rejects invalid padding.

https://datatracker.ietf.org/doc/html/rfc4648#section-12

Index

Types

// Undocumented types:
type decoder;
type encoder;
type encoding;

Globals

let std_encoding: encoding;
let url_encoding: encoding;

Functions

fn decode(io::handle, *encoding, []u8) (size | io::EOF | io::error);
fn decodeslice(*encoding, []u8) ([]u8 | errors::invalid);
fn decodestr(*encoding, str) ([]u8 | errors::invalid);
fn encode(io::handle, *encoding, []u8) (size | io::error);
fn encodeslice(*encoding, []u8) []u8;
fn encodestr(*encoding, []u8) str;
fn encoding_init(*encoding, str) void;
fn newdecoder(*encoding, io::handle) decoder;
fn newencoder(*encoding, io::handle) encoder;

Types

type decoder[link]

Show undocumented member 
type decoder = struct {
	stream: io::stream,
	in: io::handle,
	enc: *encoding,
	avail: []u8,
	// leftover decoded output
	pad: bool,
	// if padding was seen in a previous read
	state: (void | io::EOF | io::error),
};

type encoder[link]

Show undocumented member 
type encoder = struct {
	stream: io::stream,
	out: io::handle,
	enc: *encoding,
	buf: [2]u8,
	// leftover input
	avail: size,
	// bytes available in buf
	err: (void | io::error),
};

type encoding[link]

Show undocumented member 
type encoding = struct {
	encmap: [64]u8,
	decmap: [256]u8,
	valid: [256]bool,
};

Globals

let std_encoding[link] 

const std_encoding: encoding;

Represents the standard base-64 encoding alphabet as defined in RFC 4648.

let url_encoding[link] 

const url_encoding: encoding;

Represents the "base64url" alphabet as defined in RFC 4648, suitable for use in URLs and file paths.

Functions

fn decode[link] 

fn decode(in: io::handle, enc: *encoding, buf: []u8) (size | io::EOF | io::error);

Decodes base64 data from a stream using the given alphabet, returning the number of bytes of bytes read (i.e. len(buf)).

fn decodeslice[link] 

fn decodeslice(enc: *encoding, in: []u8) ([]u8 | errors::invalid);

Decodes a byte slice of ASCII-encoded base 64 data, using the given encoding, returning a slice of decoded bytes. The caller must free the return value.

fn decodestr[link] 

fn decodestr(enc: *encoding, in: str) ([]u8 | errors::invalid);

Decodes a string of ASCII-encoded base 64 data, using the given encoding, returning a slice of decoded bytes. The caller must free the return value.

fn encode[link] 

fn encode(out: io::handle, enc: *encoding, buf: []u8) (size | io::error);

Encodes base64 data using the given alphabet and writes it to a stream, returning the number of bytes of data written (i.e. len(buf)).

fn encodeslice[link] 

fn encodeslice(enc: *encoding, in: []u8) []u8;

Encodes a byte slice in base 64, using the given encoding, returning a slice of ASCII bytes. The caller must free the return value.

fn encodestr[link] 

fn encodestr(enc: *encoding, in: []u8) str;

Encodes a byte slice in base 64, using the given encoding, returning a string. The caller must free the return value.

fn encoding_init[link] 

fn encoding_init(enc: *encoding, alphabet: str) void;

Initializes a new encoding based on the passed alphabet, which must be a 64-byte ASCII string.

fn newdecoder[link] 

fn newdecoder(enc: *encoding, in: io::handle) decoder;

Creates a stream that reads and decodes base 64 data from a secondary stream. This stream does not need to be closed, and closing it will not close the underlying stream.

fn newencoder[link] 

fn newencoder(enc: *encoding, out: io::handle) encoder;

Creates a stream that encodes writes as base64 before writing them to a secondary stream. The encoder stream must be closed to finalize any unwritten bytes. Closing this stream will not close the underlying stream.