Struct base64::write::EncoderStringWriter

pub struct EncoderStringWriter<'e, E: Engine, S: StrConsumer> { /* private fields */ }

A Write implementation that base64-encodes data using the provided config and accumulates the resulting base64 utf8 &str in a StrConsumer implementation (typically String), which is then exposed via into_inner().

Examples

Buffer base64 in a new String:

use std::io::Write;
use base64::engine::general_purpose;

let mut enc = base64::write::EncoderStringWriter::new(&general_purpose::STANDARD);

enc.write_all(b"asdf").unwrap();

// get the resulting String
let b64_string = enc.into_inner();

assert_eq!("YXNkZg==", &b64_string);

Or, append to an existing String, which implements StrConsumer:

use std::io::Write;
use base64::engine::general_purpose;

let mut buf = String::from("base64: ");

let mut enc = base64::write::EncoderStringWriter::from_consumer(
    &mut buf,
    &general_purpose::STANDARD);

enc.write_all(b"asdf").unwrap();

// release the &mut reference on buf
let _ = enc.into_inner();

assert_eq!("base64: YXNkZg==", &buf);

Panics

Calling write() (or related methods) or finish() after finish() has completed without error is invalid and will panic.

Performance

Because it has to validate that the base64 is UTF-8, it is about 80% as fast as writing plain bytes to a io::Write.

Implementations

impl<'e, E: Engine, S: StrConsumer> EncoderStringWriter<'e, E, S>

pub fn from_consumer(str_consumer: S, engine: &'e E) -> Self

Create a EncoderStringWriter that will append to the provided StrConsumer.

pub fn into_inner(self) -> S

Encode all remaining buffered data, including any trailing incomplete input triples and associated padding.

Returns the base64-encoded form of the accumulated written data.

impl<'e, E: Engine> EncoderStringWriter<'e, E, String>

pub fn new(engine: &'e E) -> Self

Create a EncoderStringWriter that will encode into a new String with the provided config.

Trait Implementations

impl<'e, E: Engine, S: StrConsumer> Write for EncoderStringWriter<'e, E, S>

fn write(&mut self, buf: &[u8]) -> Result<usize>

Write a buffer into this writer, returning how many bytes were written.

fn flush(&mut self) -> Result<()>

Flush this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Writer has an efficient write_vectored implementation.

fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, fmt: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self

Creates a “by reference” adapter for this instance of Write.