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std.base64.Encoder

type pub Encoder

A type for encoding raw input as a base64 sequence of bytes.

Line wrapping isn't performed by this type, so if line sizes must be limited this must be done manually after encoding the data as base64.

Padding is applied by default. This can be disabled by setting Encoder.padding to false:

import std.base64 (Encoder)

let enc = Encoder.new

enc.padding = false

Examples

Encoding input using the standard alphabet:

import std.base64 (Encoder)

let in = 'abcdefghijklmnopqrstuvwxyz0123456789|@{}/&#[]\\!?()<>=+*;\'"`:^%$~'.to_byte_array
let out = ByteArray.new

Encoder.new.encode(in, out)
out.into_string #=> 'YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU2Nzg5fEB7fS8mI1tdXCE/KCk8Pj0rKjsnImA6XiUkfg=='

Encoding input using the URL safe alphabet:

import std.base64 (Encoder)

let in = 'abcdefghijklmnopqrstuvwxyz0123456789|@{}/&#[]\\!?()<>=+*;\'"`:^%$~'.to_byte_array
let out = ByteArray.new

Encoder.url_safe.encode(in, out)
out.into_string #=> 'YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU2Nzg5fEB7fS8mI1tdXCE_KCk8Pj0rKjsnImA6XiUkfg=='

Fields

padding

let pub @padding: Bool

If padding should be applied.

Static methods

new

Show source code

fn pub static new -> Encoder {
  Encoder(
    table0: ENCODE_STD.get(0),
    table1: ENCODE_STD.get(1),
    table2: ENCODE_STD.get(2),
    padding: true,
  )
}

fn pub static new -> Encoder

Returns an Encoder that uses the standard base64 alphabet.

url_safe

Show source code

fn pub static url_safe -> Encoder {
  Encoder(
    table0: ENCODE_URL.get(0),
    table1: ENCODE_URL.get(1),
    table2: ENCODE_URL.get(2),
    padding: true,
  )
}

fn pub static url_safe -> Encoder

Returns an Encoder that uses the URL safe base64 alphabet.

Instance methods

encode

Show source code

fn pub encode(input: ref ByteArray, into: mut ByteArray) {
  # The implementation here is based on the base64 encoder found in Google
  # Chrome (https://github.com/chromium/chromium/blob/fd8a8914ca0183f0add65ae55f04e287543c7d4a/third_party/modp_b64/modp_b64.cc).
  let t0 = @table0
  let t1 = @table1
  let t2 = @table2
  let size = input.size
  let mut i = 0

  if size > 2 {
    let max = size - 2

    while i < max {
      let b0 = input.get(i)
      let b1 = input.get(i + 1)
      let b2 = input.get(i + 2)

      into.push(t0.get(b0))
      into.push(t1.get((b0 & 0x03 << 4) | (b1 >> 4 & 0x0F)))
      into.push(t1.get((b1 & 0x0F << 2) | (b2 >> 6 & 0x03)))
      into.push(t2.get(b2))

      i += 3
    }
  }

  match size - i {
    case 0 -> {}
    case 1 -> {
      let b0 = input.get(i)

      into.push(t0.get(b0))
      into.push(t1.get(b0 & 0x03 << 4))

      if @padding {
        into.push(PAD)
        into.push(PAD)
      }
    }
    case _ -> {
      let b0 = input.get(i)
      let b1 = input.get(i + 1)

      into.push(t0.get(b0))
      into.push(t1.get((b0 & 0x03 << 4) | (b1 >> 4 & 0x0F)))
      into.push(t2.get(b1 & 0x0F << 2))

      if @padding { into.push(PAD) }
    }
  }
}

fn pub encode(input: ref ByteArray, into: mut ByteArray)

Encodes the input ByteArray into a sequence of base64 encoded bytes, appending the sequence to into.

Examples

import std.base64 (Encoder)

let out = ByteArray.new

Encoder.new.encode('hello world'.to_byte_array, out)
out.into_string #=> 'aGVsbG8gd29ybGQ='