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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 01:47:29 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 01:47:29 +0000 |
commit | 0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d (patch) | |
tree | a31f07c9bcca9d56ce61e9a1ffd30ef350d513aa /third_party/rust/base64/src/encode.rs | |
parent | Initial commit. (diff) | |
download | firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.tar.xz firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.zip |
Adding upstream version 115.8.0esr.upstream/115.8.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/base64/src/encode.rs')
-rw-r--r-- | third_party/rust/base64/src/encode.rs | 488 |
1 files changed, 488 insertions, 0 deletions
diff --git a/third_party/rust/base64/src/encode.rs b/third_party/rust/base64/src/encode.rs new file mode 100644 index 0000000000..cb176504a1 --- /dev/null +++ b/third_party/rust/base64/src/encode.rs @@ -0,0 +1,488 @@ +#[cfg(any(feature = "alloc", feature = "std", test))] +use alloc::string::String; +use core::fmt; +#[cfg(any(feature = "std", test))] +use std::error; + +#[cfg(any(feature = "alloc", feature = "std", test))] +use crate::engine::general_purpose::STANDARD; +use crate::engine::{Config, Engine}; +use crate::PAD_BYTE; + +/// Encode arbitrary octets as base64 using the [`STANDARD` engine](STANDARD). +/// +/// See [Engine::encode]. +#[allow(unused)] +#[deprecated(since = "0.21.0", note = "Use Engine::encode")] +#[cfg(any(feature = "alloc", feature = "std", test))] +pub fn encode<T: AsRef<[u8]>>(input: T) -> String { + STANDARD.encode(input) +} + +///Encode arbitrary octets as base64 using the provided `Engine` into a new `String`. +/// +/// See [Engine::encode]. +#[allow(unused)] +#[deprecated(since = "0.21.0", note = "Use Engine::encode")] +#[cfg(any(feature = "alloc", feature = "std", test))] +pub fn encode_engine<E: Engine, T: AsRef<[u8]>>(input: T, engine: &E) -> String { + engine.encode(input) +} + +///Encode arbitrary octets as base64 into a supplied `String`. +/// +/// See [Engine::encode_string]. +#[allow(unused)] +#[deprecated(since = "0.21.0", note = "Use Engine::encode_string")] +#[cfg(any(feature = "alloc", feature = "std", test))] +pub fn encode_engine_string<E: Engine, T: AsRef<[u8]>>( + input: T, + output_buf: &mut String, + engine: &E, +) { + engine.encode_string(input, output_buf) +} + +/// Encode arbitrary octets as base64 into a supplied slice. +/// +/// See [Engine::encode_slice]. +#[allow(unused)] +#[deprecated(since = "0.21.0", note = "Use Engine::encode_slice")] +pub fn encode_engine_slice<E: Engine, T: AsRef<[u8]>>( + input: T, + output_buf: &mut [u8], + engine: &E, +) -> Result<usize, EncodeSliceError> { + engine.encode_slice(input, output_buf) +} + +/// B64-encode and pad (if configured). +/// +/// This helper exists to avoid recalculating encoded_size, which is relatively expensive on short +/// inputs. +/// +/// `encoded_size` is the encoded size calculated for `input`. +/// +/// `output` must be of size `encoded_size`. +/// +/// All bytes in `output` will be written to since it is exactly the size of the output. +pub(crate) fn encode_with_padding<E: Engine + ?Sized>( + input: &[u8], + output: &mut [u8], + engine: &E, + expected_encoded_size: usize, +) { + debug_assert_eq!(expected_encoded_size, output.len()); + + let b64_bytes_written = engine.internal_encode(input, output); + + let padding_bytes = if engine.config().encode_padding() { + add_padding(input.len(), &mut output[b64_bytes_written..]) + } else { + 0 + }; + + let encoded_bytes = b64_bytes_written + .checked_add(padding_bytes) + .expect("usize overflow when calculating b64 length"); + + debug_assert_eq!(expected_encoded_size, encoded_bytes); +} + +/// Calculate the base64 encoded length for a given input length, optionally including any +/// appropriate padding bytes. +/// +/// Returns `None` if the encoded length can't be represented in `usize`. This will happen for +/// input lengths in approximately the top quarter of the range of `usize`. +pub fn encoded_len(bytes_len: usize, padding: bool) -> Option<usize> { + let rem = bytes_len % 3; + + let complete_input_chunks = bytes_len / 3; + let complete_chunk_output = complete_input_chunks.checked_mul(4); + + if rem > 0 { + if padding { + complete_chunk_output.and_then(|c| c.checked_add(4)) + } else { + let encoded_rem = match rem { + 1 => 2, + 2 => 3, + _ => unreachable!("Impossible remainder"), + }; + complete_chunk_output.and_then(|c| c.checked_add(encoded_rem)) + } + } else { + complete_chunk_output + } +} + +/// Write padding characters. +/// `input_len` is the size of the original, not encoded, input. +/// `output` is the slice where padding should be written, of length at least 2. +/// +/// Returns the number of padding bytes written. +pub(crate) fn add_padding(input_len: usize, output: &mut [u8]) -> usize { + // TODO base on encoded len to use cheaper mod by 4 (aka & 7) + let rem = input_len % 3; + let mut bytes_written = 0; + for _ in 0..((3 - rem) % 3) { + output[bytes_written] = PAD_BYTE; + bytes_written += 1; + } + + bytes_written +} + +/// Errors that can occur while encoding into a slice. +#[derive(Clone, Debug, PartialEq, Eq)] +pub enum EncodeSliceError { + /// The provided slice is too small. + OutputSliceTooSmall, +} + +impl fmt::Display for EncodeSliceError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + match self { + Self::OutputSliceTooSmall => write!(f, "Output slice too small"), + } + } +} + +#[cfg(any(feature = "std", test))] +impl error::Error for EncodeSliceError { + fn cause(&self) -> Option<&dyn error::Error> { + None + } +} + +#[cfg(test)] +mod tests { + use super::*; + + use crate::{ + alphabet, + engine::general_purpose::{GeneralPurpose, NO_PAD, STANDARD}, + tests::{assert_encode_sanity, random_config, random_engine}, + }; + use rand::{ + distributions::{Distribution, Uniform}, + Rng, SeedableRng, + }; + use std::str; + + const URL_SAFE_NO_PAD_ENGINE: GeneralPurpose = GeneralPurpose::new(&alphabet::URL_SAFE, NO_PAD); + + #[test] + fn encoded_size_correct_standard() { + assert_encoded_length(0, 0, &STANDARD, true); + + assert_encoded_length(1, 4, &STANDARD, true); + assert_encoded_length(2, 4, &STANDARD, true); + assert_encoded_length(3, 4, &STANDARD, true); + + assert_encoded_length(4, 8, &STANDARD, true); + assert_encoded_length(5, 8, &STANDARD, true); + assert_encoded_length(6, 8, &STANDARD, true); + + assert_encoded_length(7, 12, &STANDARD, true); + assert_encoded_length(8, 12, &STANDARD, true); + assert_encoded_length(9, 12, &STANDARD, true); + + assert_encoded_length(54, 72, &STANDARD, true); + + assert_encoded_length(55, 76, &STANDARD, true); + assert_encoded_length(56, 76, &STANDARD, true); + assert_encoded_length(57, 76, &STANDARD, true); + + assert_encoded_length(58, 80, &STANDARD, true); + } + + #[test] + fn encoded_size_correct_no_pad() { + assert_encoded_length(0, 0, &URL_SAFE_NO_PAD_ENGINE, false); + + assert_encoded_length(1, 2, &URL_SAFE_NO_PAD_ENGINE, false); + assert_encoded_length(2, 3, &URL_SAFE_NO_PAD_ENGINE, false); + assert_encoded_length(3, 4, &URL_SAFE_NO_PAD_ENGINE, false); + + assert_encoded_length(4, 6, &URL_SAFE_NO_PAD_ENGINE, false); + assert_encoded_length(5, 7, &URL_SAFE_NO_PAD_ENGINE, false); + assert_encoded_length(6, 8, &URL_SAFE_NO_PAD_ENGINE, false); + + assert_encoded_length(7, 10, &URL_SAFE_NO_PAD_ENGINE, false); + assert_encoded_length(8, 11, &URL_SAFE_NO_PAD_ENGINE, false); + assert_encoded_length(9, 12, &URL_SAFE_NO_PAD_ENGINE, false); + + assert_encoded_length(54, 72, &URL_SAFE_NO_PAD_ENGINE, false); + + assert_encoded_length(55, 74, &URL_SAFE_NO_PAD_ENGINE, false); + assert_encoded_length(56, 75, &URL_SAFE_NO_PAD_ENGINE, false); + assert_encoded_length(57, 76, &URL_SAFE_NO_PAD_ENGINE, false); + + assert_encoded_length(58, 78, &URL_SAFE_NO_PAD_ENGINE, false); + } + + #[test] + fn encoded_size_overflow() { + assert_eq!(None, encoded_len(usize::MAX, true)); + } + + #[test] + fn encode_engine_string_into_nonempty_buffer_doesnt_clobber_prefix() { + let mut orig_data = Vec::new(); + let mut prefix = String::new(); + let mut encoded_data_no_prefix = String::new(); + let mut encoded_data_with_prefix = String::new(); + let mut decoded = Vec::new(); + + let prefix_len_range = Uniform::new(0, 1000); + let input_len_range = Uniform::new(0, 1000); + + let mut rng = rand::rngs::SmallRng::from_entropy(); + + for _ in 0..10_000 { + orig_data.clear(); + prefix.clear(); + encoded_data_no_prefix.clear(); + encoded_data_with_prefix.clear(); + decoded.clear(); + + let input_len = input_len_range.sample(&mut rng); + + for _ in 0..input_len { + orig_data.push(rng.gen()); + } + + let prefix_len = prefix_len_range.sample(&mut rng); + for _ in 0..prefix_len { + // getting convenient random single-byte printable chars that aren't base64 is + // annoying + prefix.push('#'); + } + encoded_data_with_prefix.push_str(&prefix); + + let engine = random_engine(&mut rng); + engine.encode_string(&orig_data, &mut encoded_data_no_prefix); + engine.encode_string(&orig_data, &mut encoded_data_with_prefix); + + assert_eq!( + encoded_data_no_prefix.len() + prefix_len, + encoded_data_with_prefix.len() + ); + assert_encode_sanity( + &encoded_data_no_prefix, + engine.config().encode_padding(), + input_len, + ); + assert_encode_sanity( + &encoded_data_with_prefix[prefix_len..], + engine.config().encode_padding(), + input_len, + ); + + // append plain encode onto prefix + prefix.push_str(&encoded_data_no_prefix); + + assert_eq!(prefix, encoded_data_with_prefix); + + engine + .decode_vec(&encoded_data_no_prefix, &mut decoded) + .unwrap(); + assert_eq!(orig_data, decoded); + } + } + + #[test] + fn encode_engine_slice_into_nonempty_buffer_doesnt_clobber_suffix() { + let mut orig_data = Vec::new(); + let mut encoded_data = Vec::new(); + let mut encoded_data_original_state = Vec::new(); + let mut decoded = Vec::new(); + + let input_len_range = Uniform::new(0, 1000); + + let mut rng = rand::rngs::SmallRng::from_entropy(); + + for _ in 0..10_000 { + orig_data.clear(); + encoded_data.clear(); + encoded_data_original_state.clear(); + decoded.clear(); + + let input_len = input_len_range.sample(&mut rng); + + for _ in 0..input_len { + orig_data.push(rng.gen()); + } + + // plenty of existing garbage in the encoded buffer + for _ in 0..10 * input_len { + encoded_data.push(rng.gen()); + } + + encoded_data_original_state.extend_from_slice(&encoded_data); + + let engine = random_engine(&mut rng); + + let encoded_size = encoded_len(input_len, engine.config().encode_padding()).unwrap(); + + assert_eq!( + encoded_size, + engine.encode_slice(&orig_data, &mut encoded_data).unwrap() + ); + + assert_encode_sanity( + str::from_utf8(&encoded_data[0..encoded_size]).unwrap(), + engine.config().encode_padding(), + input_len, + ); + + assert_eq!( + &encoded_data[encoded_size..], + &encoded_data_original_state[encoded_size..] + ); + + engine + .decode_vec(&encoded_data[0..encoded_size], &mut decoded) + .unwrap(); + assert_eq!(orig_data, decoded); + } + } + + #[test] + fn encode_to_slice_random_valid_utf8() { + let mut input = Vec::new(); + let mut output = Vec::new(); + + let input_len_range = Uniform::new(0, 1000); + + let mut rng = rand::rngs::SmallRng::from_entropy(); + + for _ in 0..10_000 { + input.clear(); + output.clear(); + + let input_len = input_len_range.sample(&mut rng); + + for _ in 0..input_len { + input.push(rng.gen()); + } + + let config = random_config(&mut rng); + let engine = random_engine(&mut rng); + + // fill up the output buffer with garbage + let encoded_size = encoded_len(input_len, config.encode_padding()).unwrap(); + for _ in 0..encoded_size { + output.push(rng.gen()); + } + + let orig_output_buf = output.clone(); + + let bytes_written = engine.internal_encode(&input, &mut output); + + // make sure the part beyond bytes_written is the same garbage it was before + assert_eq!(orig_output_buf[bytes_written..], output[bytes_written..]); + + // make sure the encoded bytes are UTF-8 + let _ = str::from_utf8(&output[0..bytes_written]).unwrap(); + } + } + + #[test] + fn encode_with_padding_random_valid_utf8() { + let mut input = Vec::new(); + let mut output = Vec::new(); + + let input_len_range = Uniform::new(0, 1000); + + let mut rng = rand::rngs::SmallRng::from_entropy(); + + for _ in 0..10_000 { + input.clear(); + output.clear(); + + let input_len = input_len_range.sample(&mut rng); + + for _ in 0..input_len { + input.push(rng.gen()); + } + + let engine = random_engine(&mut rng); + + // fill up the output buffer with garbage + let encoded_size = encoded_len(input_len, engine.config().encode_padding()).unwrap(); + for _ in 0..encoded_size + 1000 { + output.push(rng.gen()); + } + + let orig_output_buf = output.clone(); + + encode_with_padding(&input, &mut output[0..encoded_size], &engine, encoded_size); + + // make sure the part beyond b64 is the same garbage it was before + assert_eq!(orig_output_buf[encoded_size..], output[encoded_size..]); + + // make sure the encoded bytes are UTF-8 + let _ = str::from_utf8(&output[0..encoded_size]).unwrap(); + } + } + + #[test] + fn add_padding_random_valid_utf8() { + let mut output = Vec::new(); + + let mut rng = rand::rngs::SmallRng::from_entropy(); + + // cover our bases for length % 3 + for input_len in 0..10 { + output.clear(); + + // fill output with random + for _ in 0..10 { + output.push(rng.gen()); + } + + let orig_output_buf = output.clone(); + + let bytes_written = add_padding(input_len, &mut output); + + // make sure the part beyond bytes_written is the same garbage it was before + assert_eq!(orig_output_buf[bytes_written..], output[bytes_written..]); + + // make sure the encoded bytes are UTF-8 + let _ = str::from_utf8(&output[0..bytes_written]).unwrap(); + } + } + + fn assert_encoded_length<E: Engine>( + input_len: usize, + enc_len: usize, + engine: &E, + padded: bool, + ) { + assert_eq!(enc_len, encoded_len(input_len, padded).unwrap()); + + let mut bytes: Vec<u8> = Vec::new(); + let mut rng = rand::rngs::SmallRng::from_entropy(); + + for _ in 0..input_len { + bytes.push(rng.gen()); + } + + let encoded = engine.encode(&bytes); + assert_encode_sanity(&encoded, padded, input_len); + + assert_eq!(enc_len, encoded.len()); + } + + #[test] + fn encode_imap() { + assert_eq!( + &GeneralPurpose::new(&alphabet::IMAP_MUTF7, NO_PAD).encode(b"\xFB\xFF"), + &GeneralPurpose::new(&alphabet::STANDARD, NO_PAD) + .encode(b"\xFB\xFF") + .replace('/', ",") + ); + } +} |