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Diffstat (limited to '')
-rw-r--r-- | third_party/rust/base64/src/display.rs | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/third_party/rust/base64/src/display.rs b/third_party/rust/base64/src/display.rs new file mode 100644 index 0000000000..cc70aac225 --- /dev/null +++ b/third_party/rust/base64/src/display.rs @@ -0,0 +1,88 @@ +//! Enables base64'd output anywhere you might use a `Display` implementation, like a format string. +//! +//! ``` +//! use base64::display::Base64Display; +//! +//! let data = vec![0x0, 0x1, 0x2, 0x3]; +//! let wrapper = Base64Display::with_config(&data, base64::STANDARD); +//! +//! assert_eq!("base64: AAECAw==", format!("base64: {}", wrapper)); +//! ``` + +use super::chunked_encoder::ChunkedEncoder; +use super::Config; +use core::fmt::{Display, Formatter}; +use core::{fmt, str}; + +/// A convenience wrapper for base64'ing bytes into a format string without heap allocation. +pub struct Base64Display<'a> { + bytes: &'a [u8], + chunked_encoder: ChunkedEncoder, +} + +impl<'a> Base64Display<'a> { + /// Create a `Base64Display` with the provided config. + pub fn with_config(bytes: &[u8], config: Config) -> Base64Display { + Base64Display { + bytes, + chunked_encoder: ChunkedEncoder::new(config), + } + } +} + +impl<'a> Display for Base64Display<'a> { + fn fmt(&self, formatter: &mut Formatter) -> Result<(), fmt::Error> { + let mut sink = FormatterSink { f: formatter }; + self.chunked_encoder.encode(self.bytes, &mut sink) + } +} + +struct FormatterSink<'a, 'b: 'a> { + f: &'a mut Formatter<'b>, +} + +impl<'a, 'b: 'a> super::chunked_encoder::Sink for FormatterSink<'a, 'b> { + type Error = fmt::Error; + + fn write_encoded_bytes(&mut self, encoded: &[u8]) -> Result<(), Self::Error> { + // Avoid unsafe. If max performance is needed, write your own display wrapper that uses + // unsafe here to gain about 10-15%. + self.f + .write_str(str::from_utf8(encoded).expect("base64 data was not utf8")) + } +} + +#[cfg(test)] +mod tests { + use super::super::chunked_encoder::tests::{ + chunked_encode_matches_normal_encode_random, SinkTestHelper, + }; + use super::super::*; + use super::*; + + #[test] + fn basic_display() { + assert_eq!( + "~$Zm9vYmFy#*", + format!("~${}#*", Base64Display::with_config(b"foobar", STANDARD)) + ); + assert_eq!( + "~$Zm9vYmFyZg==#*", + format!("~${}#*", Base64Display::with_config(b"foobarf", STANDARD)) + ); + } + + #[test] + fn display_encode_matches_normal_encode() { + let helper = DisplaySinkTestHelper; + chunked_encode_matches_normal_encode_random(&helper); + } + + struct DisplaySinkTestHelper; + + impl SinkTestHelper for DisplaySinkTestHelper { + fn encode_to_string(&self, config: Config, bytes: &[u8]) -> String { + format!("{}", Base64Display::with_config(bytes, config)) + } + } +} |