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//! Base64 encoding and decoding. //! //! # Quick Examples //! //! Encode a message using standard base64 alphabet //! ``` //! use radix64::STD; //! assert_eq!(STD.encode("my message"), "bXkgbWVzc2FnZQ=="); //! ``` //! //! Encode multiple messages while reusing a single buffer. This can be much more efficient when encoding many messages. //! ``` //! use radix64::STD; //! let mut buffer = Vec::new(); //! assert_eq!(STD.encode_with_buffer("my message", &mut buffer), "bXkgbWVzc2FnZQ=="); //! assert_eq!(STD.encode_with_buffer("my message2", &mut buffer), "bXkgbWVzc2FnZTI="); //! assert_eq!(STD.encode_with_buffer("my message3", &mut buffer), "bXkgbWVzc2FnZTM="); //! ``` //! //! Decode a message using URL safe alphabet //! ``` //! use radix64::URL_SAFE; //! assert_eq!(URL_SAFE.decode("ABCD").unwrap(), &[0, 16, 131]); //! ``` //! //! Decode multiple messages while reusing a single buffer. This can be much more efficient when decoding many messages. //! ``` //! use radix64::URL_SAFE; //! let mut buffer = Vec::new(); //! assert_eq!(URL_SAFE.decode_with_buffer("ABCD", &mut buffer).unwrap(), &[0, 16, 131]); //! assert_eq!(URL_SAFE.decode_with_buffer("ABCE", &mut buffer).unwrap(), &[0, 16, 132]); //! assert_eq!(URL_SAFE.decode_with_buffer("ABCF", &mut buffer).unwrap(), &[0, 16, 133]); //! ``` //! //! Decode data from stdin. //! ``` //! # fn example() -> Result<(), Box<std::error::Error>> { //! # use std::io::Read; //! use radix64::{STD, io::DecodeReader}; //! let mut reader = DecodeReader::new(STD, std::io::stdin()); //! let mut decoded = Vec::new(); //! reader.read_to_end(&mut decoded)?; //! # Ok(()) //! # } //! ``` //! //! Encode data to stdout. //! ``` //! # fn example() -> Result<(), Box<std::error::Error>> { //! # use std::io::Write; //! use radix64::{STD, io::EncodeWriter}; //! let mut writer = EncodeWriter::new(STD, std::io::stdout()); //! writer.write_all("my message".as_bytes())?; //! # Ok(()) //! # } //! ``` //! //! # Configs //! //! There are a variety of base64 configurations. There are constants defined //! representing the most common varieties and the ability to define a custom //! configuration using [CustomConfig](struct.CustomConfig.html). Each //! configuration has a set of methods for encoding and decoding. The methods //! are as follows: //! //! #### Encoding //! | Function | Output | Allocates | //! | -------------------- | ---------------------------------- | -------------------------------- | //! | `encode` | Returns a new `String` | Always | //! | `encode_with_buffer` | Returns a `&str` within the buffer | Only if the buffer needs to grow | //! | `encode_slice` | Writes to provided `&mut [u8]` | Never | //! //! #### Decoding //! | Function | Output | Allocates | //! | -------------------- | ----------------------------------- | -------------------------------- | //! | `decode` | Returns a new `Vec<u8>` | Always | //! | `decode_with_buffer` | Returns a `&[u8]` within the buffer | Only if the buffer needs to grow | //! | `decode_slice` | Writes to provided `&mut [u8]` | Never | //! //! # Performance //! //! The provided configurations `STD`, `URL_SAFE`, and `CRYPT` (along with the //! `NO_PAD` alternatives) each provide an AVX2 optimized implementation. When //! running on an AVX2 enabled CPU this can be dramatically faster. This library //! also strives to perform efficiently when not using AVX2. Here is a summary of //! results compared with the `base64` (v0.10.1) crate. These results were run //! on an AVX2 enabled workstation and are only meant to serve as a reference. //! Performance measurements can be very fickle, always measure a representative //! workload on your system for the most accurate comparisons. //! //! ## With AVX2 enabled //! #### Encoding //! | Input Byte Size | radix64 Throughput | base64 Throughput | //! | --------------- | ------------------ | ----------------- | //! | 3 bytes | 508 MiB/s | 344 MiB/s | //! | 32 bytes | 2.09 GiB/s | 1.30 GiB/s | //! | 128 bytes | 4.16 GiB/s | 1.92 GiB/s | //! | 8192 bytes | 5.94 GiB/s | 2.25 GiB/s | //! //! #### Decoding //! | Input Byte Size | radix64 Throughput | base64 Throughput | //! | --------------- | ------------------ | ----------------- | //! | 3 bytes | 293 MiB/s | 178 MiB/s | //! | 32 bytes | 1.47 GiB/s | 973 MiB/s | //! | 128 bytes | 3.85 GiB/s | 1.55 GiB/s | //! | 8192 bytes | 8.21 GiB/s | 1.93 GiB/s | //! //! ## Without any SIMD optimizations (--no-default-features) //! #### Encoding //! | Input Byte Size | radix64 Throughput | base64 Throughput | //! | --------------- | ------------------ | ----------------- | //! | 3 bytes | 530 MiB/s | 347 MiB/s | //! | 32 bytes | 1.54 GiB/s | 1.29 GiB/s | //! | 128 bytes | 2.01 GiB/s | 1.91 GiB/s | //! | 8192 bytes | 2.25 GiB/s | 2.20 GiB/s | //! //! #### Decoding //! | Input Byte Size | radix64 Throughput | base64 Throughput | //! | --------------- | ------------------ | ----------------- | //! | 3 bytes | 302 MiB/s | 178 MiB/s | //! | 32 bytes | 969 MiB/s | 976 MiB/s | //! | 128 bytes | 1.59 GiB/s | 1.55 GiB/s | //! | 8192 bytes | 2.04 GiB/s | 1.98 GiB/s | #![deny(missing_docs)] #[doc(inline)] pub use crate::configs::CustomConfig; pub use crate::decode::DecodeError; pub use crate::display::Display; use crate::configs::{Crypt, Fast, Std, StdNoPad, UrlSafe, UrlSafeNoPad}; /// Encode and Decode using the standard characer set with padding. /// /// See [RFC 4648](https://tools.ietf.org/html/rfc4648#section-4) pub const STD: Std = Std; /// Encode and Decode using the standard characer set *without* padding. /// /// See [RFC 4648](https://tools.ietf.org/html/rfc4648#section-4) pub const STD_NO_PAD: StdNoPad = StdNoPad; /// Encode and Decode using the URL safe characer set with padding. /// /// See [RFC 4648](https://tools.ietf.org/html/rfc4648#section-5) pub const URL_SAFE: UrlSafe = UrlSafe; /// Encode and Decode using the URL safe characer set *without* padding. /// /// See [RFC 4648](https://tools.ietf.org/html/rfc4648#section-5) pub const URL_SAFE_NO_PAD: UrlSafeNoPad = UrlSafeNoPad; /// Encode and Decode using the `crypt(3)` character set. pub const CRYPT: Crypt = Crypt; /// Encode and Decode using a fast alphabet with no padding. /// /// This is not part of any official specification and should only be used when /// interoperability is not a concern. The alphabet used is\ /// ``:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz``\ /// It's specifically tailored for fast encoding and decoding when AVX2 is in /// use. pub const FAST: Fast = Fast; mod private { use crate::decode::block::IntoBlockDecoder; use crate::encode::block::IntoBlockEncoder; use crate::u6::U6; pub trait SealedConfig: IntoBlockEncoder + IntoBlockDecoder { /// Encodes the six bits of input into the 8 bits of output. fn encode_u6(self, input: U6) -> u8; /// Decodes the encoded byte into six bits matching the original input. /// config::INVALID_VALUE is returned on invalid input. fn decode_u8(self, input: u8) -> u8; /// Indicates whether this configuration uses padding and if so, which /// character to use. fn padding_byte(self) -> Option<u8>; } } /// Config represents a base64 configuration. /// /// Each Config provides methods to encode and decode according to the /// configuration. This trait is sealed and not intended to be implemented /// outside of this crate. Custom configurations can be defined using /// [CustomConfig](struct.CustomConfig.html). pub trait Config: Copy + private::SealedConfig { /// Encode the provided input into a String. #[inline] fn encode<I>(self, input: &I) -> String where I: AsRef<[u8]> + ?Sized, { let input = input.as_ref(); let mut output = vec![0; input.len() * 4 / 3 + 3]; let bytes_written = crate::encode::encode_slice(self, input, output.as_mut_slice()); output.truncate(bytes_written); // The builtin alphabets are all ascii and the CustomConfigBuilder // ensures any custom alphabets only contain ascii characters as well. // Therefore we can bypass the utf8 check on the encoded output. debug_assert!(output.iter().all(u8::is_ascii)); unsafe { String::from_utf8_unchecked(output) } } /// Encode the provided input into the provided buffer, returning a &str of /// the encoded input. The returned &str is a view into the beginning of the /// provided buffer that contains the encoded data. This method *overwrites* /// the data in the buffer, it *does not* append to the buffer. This method /// exists to provide an efficient way to amortize allocations when /// repeatedly encoding different inputs. The same buffer can be provided for /// each invocation and will only be resized when necessary. Any data in the /// buffer outside the range of the returned &str is not part of the encoded /// output and should be ignored. #[inline] fn encode_with_buffer<'i, 'b, I>(self, input: &'i I, buffer: &'b mut Vec<u8>) -> &'b str where I: AsRef<[u8]> + ?Sized, { let input = input.as_ref(); let output_size = input.len() * 4 / 3 + 3; if output_size > buffer.len() { buffer.resize(output_size, 0); } let num_encoded_bytes = crate::encode::encode_slice(self, input, buffer.as_mut_slice()); let encoded = &buffer[..num_encoded_bytes]; // The builtin alphabets are all ascii and the CustomConfigBuilder // ensures any custom alphabets only contain ascii characters as well. // Therefore we can bypass the utf8 check on the encoded output. debug_assert!(encoded.iter().all(u8::is_ascii)); unsafe { std::str::from_utf8_unchecked(encoded) } } /// Encode the provided input into the provided output slice. The slice must /// be large enough to contain the encoded output and panics if it's not. /// Use `input.len() * 4 / 3 + 3` as a conservative estimate. It returns the /// number of bytes of encoded output written to the output slice. This /// method allows for the most control over memory placement, but /// `encode_with_buffer` is typically more ergonomic and just as performant. #[inline] fn encode_slice<I>(self, input: &I, output: &mut [u8]) -> usize where I: AsRef<[u8]> + ?Sized, { crate::encode::encode_slice(self, input.as_ref(), output) } /// Decode the provided input. #[inline] fn decode<I>(self, input: &I) -> Result<Vec<u8>, DecodeError> where I: AsRef<[u8]> + ?Sized, { let mut output = Vec::new(); let decoded_len = self.decode_with_buffer(input, &mut output)?.len(); output.truncate(decoded_len); Ok(output) } /// Decode the provided input into the provided buffer, returning a &[u8] of /// the decoded input. The returned &[u8] is a view into the beginning of the /// provided buffer that contains the decoded data. This method *overwrites* /// the data in the buffer, it *does not* append to the buffer. This method /// exists to provide an efficient way to amortize allocations when /// repeatedly decoding different inputs. The same buffer can be provided for /// each invocation and will only be resized when necessary. Any data in the /// buffer outside the range of the returned &[u8] is not part of the decoded /// output and should be ignored. #[inline] fn decode_with_buffer<'i, 'b, I>( self, input: &'i I, buffer: &'b mut Vec<u8>, ) -> Result<&'b [u8], DecodeError> where I: AsRef<[u8]> + ?Sized, { let input = input.as_ref(); let output_size = input.len() * 3 / 4 + 1; if output_size > buffer.len() { buffer.resize(output_size, 0); } let num_decoded_bytes = crate::decode::decode_slice(self, input, buffer.as_mut_slice())?; Ok(&buffer[..num_decoded_bytes]) } /// Decode the provided input into the provided output slice. The slice must /// be large enough to contain the decoded output and panics if it's not. Use /// `input.len() * 6 / 8 + 1` as a conservative estimate. It returns the /// number of bytes of decoded output written to the output slice. This /// method allows for the most control over memory placement, but /// `decode_with_buffer` is typically more ergonomic and just as performant. #[inline] fn decode_slice<I>(self, input: &I, output: &mut [u8]) -> Result<usize, DecodeError> where I: AsRef<[u8]> + ?Sized, { crate::decode::decode_slice(self, input.as_ref(), output) } } /// Both encoding and decoding iterate work on chunks of input and output slices. /// This macro allows creating an efficient iterator to break the slices into /// defined chunks (possibly differents sizes for input and output) and advance /// by a defined stride (again possibly different for input and output). It uses /// unsafe mechanisms for efficiency, but the exposed api should be sound. macro_rules! define_block_iter { ( name = $name:ident, input_chunk_size = $input_chunk_size:expr, input_stride = $input_stride:expr, output_chunk_size = $output_chunk_size:expr, output_stride = $output_stride:expr ) => { /// An iterator that accepts an input slice and output slice. It yields /// (&[u8; $input_chunk_size], &mut [u8; $output_chunk_size]). Each yield /// advances the input $input_stride bytes and the output $output_stride /// bytes. struct $name<'a, 'b> { input: &'a [u8], output: &'b mut [u8], input_index: usize, output_index: usize, } impl<'a, 'b> $name<'a, 'b> { #[inline] fn new(input: &'a [u8], output: &'b mut [u8]) -> Self { $name { input, output, input_index: 0, output_index: 0, } } #[inline] fn next_chunk( &mut self, ) -> Option<(&[u8; $input_chunk_size], &mut [u8; $output_chunk_size])> { if self.input_index + $input_chunk_size <= self.input.len() && self.output_index + $output_chunk_size <= self.output.len() { use arrayref::{array_mut_ref, array_ref}; let input = array_ref!(self.input, self.input_index, $input_chunk_size); let output = array_mut_ref!(self.output, self.output_index, $output_chunk_size); self.input_index += $input_stride; self.output_index += $output_stride; Some((input, output)) } else { None } } #[allow(dead_code)] fn step_back(&mut self) { if self.input_index > 0 { self.input_index -= $input_stride; self.output_index -= $output_stride; } } #[inline] fn remaining(self) -> (usize, usize) { (self.input_index, self.output_index) } } }; } // mod definitions need to appear after the macro definition. pub mod configs; pub(crate) mod decode; pub(crate) mod display; pub(crate) mod encode; pub mod io; pub(crate) mod tables; pub(crate) mod u6; use std::ops::Bound; use std::ops::RangeBounds; // Copy the data in slice within the src range, to the index specified by dest. // This is just a stop-gap until slice::copy_within is stabilized. pub(crate) fn copy_in_place<T: Copy, R: RangeBounds<usize>>(slice: &mut [T], src: R, dest: usize) { let src_start = match src.start_bound() { Bound::Included(&n) => n, Bound::Excluded(&n) => n.checked_add(1).expect("range bound overflows usize"), Bound::Unbounded => 0, }; let src_end = match src.end_bound() { Bound::Included(&n) => n.checked_add(1).expect("range bound overflows usize"), Bound::Excluded(&n) => n, Bound::Unbounded => slice.len(), }; assert!(src_start <= src_end, "src end is before src start"); assert!(src_end <= slice.len(), "src is out of bounds"); let count = src_end - src_start; assert!(dest <= slice.len() - count, "dest is out of bounds"); unsafe { core::ptr::copy( slice.get_unchecked(src_start), slice.get_unchecked_mut(dest), count, ); } }