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