diff options
| author | mo khan <mo@mokhan.ca> | 2025-07-02 18:36:06 -0600 |
|---|---|---|
| committer | mo khan <mo@mokhan.ca> | 2025-07-02 18:36:06 -0600 |
| commit | 8cdfa445d6629ffef4cb84967ff7017654045bc2 (patch) | |
| tree | 22f0b0907c024c78d26a731e2e1f5219407d8102 /vendor/base64/src/write/encoder_string_writer.rs | |
| parent | 4351c74c7c5f97156bc94d3a8549b9940ac80e3f (diff) | |
chore: add vendor directory
Diffstat (limited to 'vendor/base64/src/write/encoder_string_writer.rs')
| -rw-r--r-- | vendor/base64/src/write/encoder_string_writer.rs | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/vendor/base64/src/write/encoder_string_writer.rs b/vendor/base64/src/write/encoder_string_writer.rs new file mode 100644 index 00000000..9c02bcde --- /dev/null +++ b/vendor/base64/src/write/encoder_string_writer.rs @@ -0,0 +1,207 @@ +use super::encoder::EncoderWriter; +use crate::engine::Engine; +use std::io; + +/// 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); +/// ``` +/// +/// # 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`. +pub struct EncoderStringWriter<'e, E: Engine, S: StrConsumer> { + encoder: EncoderWriter<'e, E, Utf8SingleCodeUnitWriter<S>>, +} + +impl<'e, E: Engine, S: StrConsumer> EncoderStringWriter<'e, E, S> { + /// Create a EncoderStringWriter that will append to the provided `StrConsumer`. + pub fn from_consumer(str_consumer: S, engine: &'e E) -> Self { + EncoderStringWriter { + encoder: EncoderWriter::new(Utf8SingleCodeUnitWriter { str_consumer }, engine), + } + } + + /// Encode all remaining buffered data, including any trailing incomplete input triples and + /// associated padding. + /// + /// Returns the base64-encoded form of the accumulated written data. + pub fn into_inner(mut self) -> S { + self.encoder + .finish() + .expect("Writing to a consumer should never fail") + .str_consumer + } +} + +impl<'e, E: Engine> EncoderStringWriter<'e, E, String> { + /// Create a EncoderStringWriter that will encode into a new `String` with the provided config. + pub fn new(engine: &'e E) -> Self { + EncoderStringWriter::from_consumer(String::new(), engine) + } +} + +impl<'e, E: Engine, S: StrConsumer> io::Write for EncoderStringWriter<'e, E, S> { + fn write(&mut self, buf: &[u8]) -> io::Result<usize> { + self.encoder.write(buf) + } + + fn flush(&mut self) -> io::Result<()> { + self.encoder.flush() + } +} + +/// An abstraction around consuming `str`s produced by base64 encoding. +pub trait StrConsumer { + /// Consume the base64 encoded data in `buf` + fn consume(&mut self, buf: &str); +} + +/// As for io::Write, `StrConsumer` is implemented automatically for `&mut S`. +impl<S: StrConsumer + ?Sized> StrConsumer for &mut S { + fn consume(&mut self, buf: &str) { + (**self).consume(buf); + } +} + +/// Pushes the str onto the end of the String +impl StrConsumer for String { + fn consume(&mut self, buf: &str) { + self.push_str(buf); + } +} + +/// A `Write` that only can handle bytes that are valid single-byte UTF-8 code units. +/// +/// This is safe because we only use it when writing base64, which is always valid UTF-8. +struct Utf8SingleCodeUnitWriter<S: StrConsumer> { + str_consumer: S, +} + +impl<S: StrConsumer> io::Write for Utf8SingleCodeUnitWriter<S> { + fn write(&mut self, buf: &[u8]) -> io::Result<usize> { + // Because we expect all input to be valid utf-8 individual bytes, we can encode any buffer + // length + let s = std::str::from_utf8(buf).expect("Input must be valid UTF-8"); + + self.str_consumer.consume(s); + + Ok(buf.len()) + } + + fn flush(&mut self) -> io::Result<()> { + // no op + Ok(()) + } +} + +#[cfg(test)] +mod tests { + use crate::{ + engine::Engine, tests::random_engine, write::encoder_string_writer::EncoderStringWriter, + }; + use rand::Rng; + use std::cmp; + use std::io::Write; + + #[test] + fn every_possible_split_of_input() { + let mut rng = rand::thread_rng(); + let mut orig_data = Vec::<u8>::new(); + let mut normal_encoded = String::new(); + + let size = 5_000; + + for i in 0..size { + orig_data.clear(); + normal_encoded.clear(); + + orig_data.resize(size, 0); + rng.fill(&mut orig_data[..]); + + let engine = random_engine(&mut rng); + engine.encode_string(&orig_data, &mut normal_encoded); + + let mut stream_encoder = EncoderStringWriter::new(&engine); + // Write the first i bytes, then the rest + stream_encoder.write_all(&orig_data[0..i]).unwrap(); + stream_encoder.write_all(&orig_data[i..]).unwrap(); + + let stream_encoded = stream_encoder.into_inner(); + + assert_eq!(normal_encoded, stream_encoded); + } + } + #[test] + fn incremental_writes() { + let mut rng = rand::thread_rng(); + let mut orig_data = Vec::<u8>::new(); + let mut normal_encoded = String::new(); + + let size = 5_000; + + for _ in 0..size { + orig_data.clear(); + normal_encoded.clear(); + + orig_data.resize(size, 0); + rng.fill(&mut orig_data[..]); + + let engine = random_engine(&mut rng); + engine.encode_string(&orig_data, &mut normal_encoded); + + let mut stream_encoder = EncoderStringWriter::new(&engine); + // write small nibbles of data + let mut offset = 0; + while offset < size { + let nibble_size = cmp::min(rng.gen_range(0..=64), size - offset); + let len = stream_encoder + .write(&orig_data[offset..offset + nibble_size]) + .unwrap(); + offset += len; + } + + let stream_encoded = stream_encoder.into_inner(); + + assert_eq!(normal_encoded, stream_encoded); + } + } +} |
