chore: add vendor dependencies for kauma build

vendor/base64/src/chunked_encoder.rs

@@ -0,0 +1,172 @@
+use crate::{
+    encode::add_padding,
+    engine::{Config, Engine},
+};
+#[cfg(any(feature = "alloc", test))]
+use alloc::string::String;
+#[cfg(any(feature = "alloc", test))]
+use core::str;
+
+/// The output mechanism for ChunkedEncoder's encoded bytes.
+pub trait Sink {
+    type Error;
+
+    /// Handle a chunk of encoded base64 data (as UTF-8 bytes)
+    fn write_encoded_bytes(&mut self, encoded: &[u8]) -> Result<(), Self::Error>;
+}
+
+/// A base64 encoder that emits encoded bytes in chunks without heap allocation.
+pub struct ChunkedEncoder<'e, E: Engine + ?Sized> {
+    engine: &'e E,
+}
+
+impl<'e, E: Engine + ?Sized> ChunkedEncoder<'e, E> {
+    pub fn new(engine: &'e E) -> ChunkedEncoder<'e, E> {
+        ChunkedEncoder { engine }
+    }
+
+    pub fn encode<S: Sink>(&self, bytes: &[u8], sink: &mut S) -> Result<(), S::Error> {
+        const BUF_SIZE: usize = 1024;
+        const CHUNK_SIZE: usize = BUF_SIZE / 4 * 3;
+
+        let mut buf = [0; BUF_SIZE];
+        for chunk in bytes.chunks(CHUNK_SIZE) {
+            let mut len = self.engine.internal_encode(chunk, &mut buf);
+            if chunk.len() != CHUNK_SIZE && self.engine.config().encode_padding() {
+                // Final, potentially partial, chunk.
+                // Only need to consider if padding is needed on a partial chunk since full chunk
+                // is a multiple of 3, which therefore won't be padded.
+                // Pad output to multiple of four bytes if required by config.
+                len += add_padding(len, &mut buf[len..]);
+            }
+            sink.write_encoded_bytes(&buf[..len])?;
+        }
+
+        Ok(())
+    }
+}
+
+// A really simple sink that just appends to a string
+#[cfg(any(feature = "alloc", test))]
+pub(crate) struct StringSink<'a> {
+    string: &'a mut String,
+}
+
+#[cfg(any(feature = "alloc", test))]
+impl<'a> StringSink<'a> {
+    pub(crate) fn new(s: &mut String) -> StringSink {
+        StringSink { string: s }
+    }
+}
+
+#[cfg(any(feature = "alloc", test))]
+impl<'a> Sink for StringSink<'a> {
+    type Error = ();
+
+    fn write_encoded_bytes(&mut self, s: &[u8]) -> Result<(), Self::Error> {
+        self.string.push_str(str::from_utf8(s).unwrap());
+
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+pub mod tests {
+    use rand::{
+        distributions::{Distribution, Uniform},
+        Rng, SeedableRng,
+    };
+
+    use crate::{
+        alphabet::STANDARD,
+        engine::general_purpose::{GeneralPurpose, GeneralPurposeConfig, PAD},
+        tests::random_engine,
+    };
+
+    use super::*;
+
+    #[test]
+    fn chunked_encode_empty() {
+        assert_eq!("", chunked_encode_str(&[], PAD));
+    }
+
+    #[test]
+    fn chunked_encode_intermediate_fast_loop() {
+        // > 8 bytes input, will enter the pretty fast loop
+        assert_eq!("Zm9vYmFyYmF6cXV4", chunked_encode_str(b"foobarbazqux", PAD));
+    }
+
+    #[test]
+    fn chunked_encode_fast_loop() {
+        // > 32 bytes input, will enter the uber fast loop
+        assert_eq!(
+            "Zm9vYmFyYmF6cXV4cXV1eGNvcmdlZ3JhdWx0Z2FycGx5eg==",
+            chunked_encode_str(b"foobarbazquxquuxcorgegraultgarplyz", PAD)
+        );
+    }
+
+    #[test]
+    fn chunked_encode_slow_loop_only() {
+        // < 8 bytes input, slow loop only
+        assert_eq!("Zm9vYmFy", chunked_encode_str(b"foobar", PAD));
+    }
+
+    #[test]
+    fn chunked_encode_matches_normal_encode_random_string_sink() {
+        let helper = StringSinkTestHelper;
+        chunked_encode_matches_normal_encode_random(&helper);
+    }
+
+    pub fn chunked_encode_matches_normal_encode_random<S: SinkTestHelper>(sink_test_helper: &S) {
+        let mut input_buf: Vec<u8> = Vec::new();
+        let mut output_buf = String::new();
+        let mut rng = rand::rngs::SmallRng::from_entropy();
+        let input_len_range = Uniform::new(1, 10_000);
+
+        for _ in 0..20_000 {
+            input_buf.clear();
+            output_buf.clear();
+
+            let buf_len = input_len_range.sample(&mut rng);
+            for _ in 0..buf_len {
+                input_buf.push(rng.gen());
+            }
+
+            let engine = random_engine(&mut rng);
+
+            let chunk_encoded_string = sink_test_helper.encode_to_string(&engine, &input_buf);
+            engine.encode_string(&input_buf, &mut output_buf);
+
+            assert_eq!(output_buf, chunk_encoded_string, "input len={}", buf_len);
+        }
+    }
+
+    fn chunked_encode_str(bytes: &[u8], config: GeneralPurposeConfig) -> String {
+        let mut s = String::new();
+
+        let mut sink = StringSink::new(&mut s);
+        let engine = GeneralPurpose::new(&STANDARD, config);
+        let encoder = ChunkedEncoder::new(&engine);
+        encoder.encode(bytes, &mut sink).unwrap();
+
+        s
+    }
+
+    // An abstraction around sinks so that we can have tests that easily to any sink implementation
+    pub trait SinkTestHelper {
+        fn encode_to_string<E: Engine>(&self, engine: &E, bytes: &[u8]) -> String;
+    }
+
+    struct StringSinkTestHelper;
+
+    impl SinkTestHelper for StringSinkTestHelper {
+        fn encode_to_string<E: Engine>(&self, engine: &E, bytes: &[u8]) -> String {
+            let encoder = ChunkedEncoder::new(engine);
+            let mut s = String::new();
+            let mut sink = StringSink::new(&mut s);
+            encoder.encode(bytes, &mut sink).unwrap();
+
+            s
+        }
+    }
+}