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| </pre><pre class="rust"><code><span class="kw">use </span><span class="kw">super</span>::encoder::EncoderWriter; |
| <span class="kw">use </span><span class="kw">crate</span>::Config; |
| <span class="kw">use </span>std::io; |
| <span class="kw">use </span>std::io::Write; |
| |
| <span class="doccomment">/// A `Write` implementation that base64-encodes data using the provided config and accumulates the |
| /// resulting base64 in memory, which is then exposed as a String via `into_inner()`. |
| /// |
| /// # Examples |
| /// |
| /// Buffer base64 in a new String: |
| /// |
| /// ``` |
| /// use std::io::Write; |
| /// |
| /// let mut enc = base64::write::EncoderStringWriter::new(base64::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: |
| /// |
| /// ``` |
| /// use std::io::Write; |
| /// |
| /// let mut buf = String::from("base64: "); |
| /// |
| /// let mut enc = base64::write::EncoderStringWriter::from(&mut buf, base64::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`. |
| </span><span class="kw">pub struct </span>EncoderStringWriter<S: StrConsumer> { |
| encoder: EncoderWriter<Utf8SingleCodeUnitWriter<S>>, |
| } |
| |
| <span class="kw">impl</span><S: StrConsumer> EncoderStringWriter<S> { |
| <span class="doccomment">/// Create a EncoderStringWriter that will append to the provided `StrConsumer`. |
| </span><span class="kw">pub fn </span>from(str_consumer: S, config: Config) -> <span class="self">Self </span>{ |
| EncoderStringWriter { |
| encoder: EncoderWriter::new(Utf8SingleCodeUnitWriter { str_consumer }, config), |
| } |
| } |
| |
| <span class="doccomment">/// Encode all remaining buffered data, including any trailing incomplete input triples and |
| /// associated padding. |
| /// |
| /// Once this succeeds, no further writes or calls to this method are allowed. |
| /// |
| /// Returns the base64-encoded form of the accumulated written data. |
| </span><span class="kw">pub fn </span>into_inner(<span class="kw-2">mut </span><span class="self">self</span>) -> S { |
| <span class="self">self</span>.encoder |
| .finish() |
| .expect(<span class="string">"Writing to a Vec<u8> should never fail"</span>) |
| .str_consumer |
| } |
| } |
| |
| <span class="kw">impl </span>EncoderStringWriter<String> { |
| <span class="doccomment">/// Create a EncoderStringWriter that will encode into a new String with the provided config. |
| </span><span class="kw">pub fn </span>new(config: Config) -> <span class="self">Self </span>{ |
| EncoderStringWriter::from(String::new(), config) |
| } |
| } |
| |
| <span class="kw">impl</span><S: StrConsumer> Write <span class="kw">for </span>EncoderStringWriter<S> { |
| <span class="kw">fn </span>write(<span class="kw-2">&mut </span><span class="self">self</span>, buf: <span class="kw-2">&</span>[u8]) -> io::Result<usize> { |
| <span class="self">self</span>.encoder.write(buf) |
| } |
| |
| <span class="kw">fn </span>flush(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<()> { |
| <span class="self">self</span>.encoder.flush() |
| } |
| } |
| |
| <span class="doccomment">/// An abstraction around consuming `str`s produced by base64 encoding. |
| </span><span class="kw">pub trait </span>StrConsumer { |
| <span class="doccomment">/// Consume the base64 encoded data in `buf` |
| </span><span class="kw">fn </span>consume(<span class="kw-2">&mut </span><span class="self">self</span>, buf: <span class="kw-2">&</span>str); |
| } |
| |
| <span class="doccomment">/// As for io::Write, `StrConsumer` is implemented automatically for `&mut S`. |
| </span><span class="kw">impl</span><S: StrConsumer + <span class="question-mark">?</span>Sized> StrConsumer <span class="kw">for </span><span class="kw-2">&mut </span>S { |
| <span class="kw">fn </span>consume(<span class="kw-2">&mut </span><span class="self">self</span>, buf: <span class="kw-2">&</span>str) { |
| (<span class="kw-2">**</span><span class="self">self</span>).consume(buf) |
| } |
| } |
| |
| <span class="doccomment">/// Pushes the str onto the end of the String |
| </span><span class="kw">impl </span>StrConsumer <span class="kw">for </span>String { |
| <span class="kw">fn </span>consume(<span class="kw-2">&mut </span><span class="self">self</span>, buf: <span class="kw-2">&</span>str) { |
| <span class="self">self</span>.push_str(buf) |
| } |
| } |
| |
| <span class="doccomment">/// 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. |
| </span><span class="kw">struct </span>Utf8SingleCodeUnitWriter<S: StrConsumer> { |
| str_consumer: S, |
| } |
| |
| <span class="kw">impl</span><S: StrConsumer> io::Write <span class="kw">for </span>Utf8SingleCodeUnitWriter<S> { |
| <span class="kw">fn </span>write(<span class="kw-2">&mut </span><span class="self">self</span>, buf: <span class="kw-2">&</span>[u8]) -> io::Result<usize> { |
| <span class="comment">// Because we expect all input to be valid utf-8 individual bytes, we can encode any buffer |
| // length |
| </span><span class="kw">let </span>s = std::str::from_utf8(buf).expect(<span class="string">"Input must be valid UTF-8"</span>); |
| |
| <span class="self">self</span>.str_consumer.consume(s); |
| |
| <span class="prelude-val">Ok</span>(buf.len()) |
| } |
| |
| <span class="kw">fn </span>flush(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<()> { |
| <span class="comment">// no op |
| </span><span class="prelude-val">Ok</span>(()) |
| } |
| } |
| |
| <span class="attribute">#[cfg(test)] |
| </span><span class="kw">mod </span>tests { |
| <span class="kw">use </span><span class="kw">crate</span>::encode_config_buf; |
| <span class="kw">use </span><span class="kw">crate</span>::tests::random_config; |
| <span class="kw">use </span><span class="kw">crate</span>::write::encoder_string_writer::EncoderStringWriter; |
| <span class="kw">use </span>rand::Rng; |
| <span class="kw">use </span>std::io::Write; |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>every_possible_split_of_input() { |
| <span class="kw">let </span><span class="kw-2">mut </span>rng = rand::thread_rng(); |
| <span class="kw">let </span><span class="kw-2">mut </span>orig_data = Vec::<u8>::new(); |
| <span class="kw">let </span><span class="kw-2">mut </span>normal_encoded = String::new(); |
| |
| <span class="kw">let </span>size = <span class="number">5_000</span>; |
| |
| <span class="kw">for </span>i <span class="kw">in </span><span class="number">0</span>..size { |
| orig_data.clear(); |
| normal_encoded.clear(); |
| |
| <span class="kw">for _ in </span><span class="number">0</span>..size { |
| orig_data.push(rng.gen()); |
| } |
| |
| <span class="kw">let </span>config = random_config(<span class="kw-2">&mut </span>rng); |
| encode_config_buf(<span class="kw-2">&</span>orig_data, config, <span class="kw-2">&mut </span>normal_encoded); |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>stream_encoder = EncoderStringWriter::new(config); |
| <span class="comment">// Write the first i bytes, then the rest |
| </span>stream_encoder.write_all(<span class="kw-2">&</span>orig_data[<span class="number">0</span>..i]).unwrap(); |
| stream_encoder.write_all(<span class="kw-2">&</span>orig_data[i..]).unwrap(); |
| |
| <span class="kw">let </span>stream_encoded = stream_encoder.into_inner(); |
| |
| <span class="macro">assert_eq!</span>(normal_encoded, stream_encoded); |
| } |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="base64" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
