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//! Correct, efficient, canonical, and generic data-encoding functions //! //! This [crate] provides little-endian ASCII base-conversion encodings for //! bases of size 2, 4, 8, 16, 32, and 64. It supports both padded and //! non-padded encodings. It supports canonical encodings (trailing bits are //! checked). It supports in-place encoding and decoding functions. It supports //! non-canonical symbols. And it supports both most and least significant //! bit-order. The performance of the encoding and decoding functions are //! similar to existing implementations (see how to run the benchmarks on //! [github]). //! //! This is the library documentation. If you are looking for the [binary], see //! the installation instructions on [github]. //! //! # Examples //! //! This crate provides predefined encodings as [constants]. These constants are //! of type [`Padded`] or [`NoPad`] whether they use padding or not. These types //! provide encoding and decoding functions with in-place or allocating //! variants. Here is an example using the allocating encoding function of //! [base64]: //! //! ``` //! use data_encoding::BASE64; //! assert_eq!(BASE64.encode(b"Hello world"), "SGVsbG8gd29ybGQ="); //! ``` //! //! It is also possible to use the non-padded version of base64 by calling the //! [`no_pad`] method of [`Padded`]: //! //! ``` //! use data_encoding::BASE64; //! assert_eq!(BASE64.no_pad().encode(b"Hello world"), "SGVsbG8gd29ybGQ"); //! ``` //! //! Here is an example using the in-place decoding function of [base32]: //! //! ``` //! use data_encoding::BASE32; //! let input = b"JBSWY3DPEB3W64TMMQ======"; //! let mut output = vec![0; BASE32.decode_len(input.len()).unwrap()]; //! let len = BASE32.decode_mut(input, &mut output).unwrap(); //! assert_eq!(&output[0 .. len], b"Hello world"); //! ``` //! //! You are not limited to the predefined encodings. You may define your own //! encodings (with the same correctness and performance properties as the //! predefined ones) using the [`Builder`] type: //! //! ```rust //! use data_encoding::Builder; //! let hex = Builder::new(b"0123456789abcdef").no_pad().unwrap(); //! assert_eq!(hex.encode(b"hello"), "68656c6c6f"); //! ``` //! //! # Properties //! //! The [base16], [base32], [base32hex], [base64], and [base64url] predefined //! encodings are conform to [RFC4648]. //! //! The encoding and decoding functions satisfy the following properties: //! //! - They are deterministic: their output only depends on their input //! - They have no side-effects: they do not modify a hidden mutable state //! - They are correct: encoding then decoding gives the initial data //! - They are canonical (unless non-canonical symbols are used or checking //! trailing bits is disabled): decoding then encoding gives the initial data //! //! This last property is usually not satisfied by common base64 implementations //! (like the `rustc-serialize` crate, the `base64` crate, or the `base64` GNU //! program). This is a matter of choice and this crate has made the choice to //! let the user choose. Support for canonical encoding as described by the //! [RFC][canonical] is provided. But it is also possible to disable checking //! trailing bits, to add non-canonical symbols, and to decode concatenated //! padded inputs. //! //! Since the RFC specifies the encoding function on all inputs and the decoding //! function on all possible encoded outputs, the differences between //! implementations come from the decoding function which may be more or less //! permissive. In this crate, the decoding function of canonical encodings //! rejects all inputs that are not a possible output of the encoding function. //! Here are some concrete examples of decoding differences between this crate, //! the `rustc-serialize` crate, the `base64` crate, and the `base64` GNU //! program: //! //! | Input | `data-encoding` | `rustc` | `base64` | GNU `base64` | //! | ---------- | --------------- | -------- | -------- | ------------- | //! | `AAB=` | `Trailing(2)` | `[0, 0]` | `[0, 0]` | `\x00\x00` | //! | `AA\nB=` | `Length(4)` | `[0, 0]` | `Err(2)` | `\x00\x00` | //! | `AAB` | `Length(0)` | `[0, 0]` | `[0, 0]` | Invalid input | //! | `A\rA\nB=` | `Length(4)` | `[0, 0]` | `Err(1)` | Invalid input | //! | `-_\r\n` | `Symbol(0)` | `[251]` | `Err(0)` | Invalid input | //! | `AA==AA==` | `Symbol(2)` | `Err` | `Err(2)` | `\x00\x00` | //! //! We can summarize these discrepancies as follows: //! //! | Discrepancy | `data-encoding` | `rustc` | `base64` | GNU `base64` | //! | ----------- | --------------- | ------- | -------- | ------------ | //! | Non-zero trailing bits | No | Yes | Yes | Yes | //! | Ignored characters | None | `\r` and `\n` | None | `\n` | //! | Translated characters | None | `-_` mapped to `+/` | None | None | //! | Padding is optional | No | Yes | Yes | No | //! | Concatenated padded input | No | No | No | Yes | //! //! This crate permits to [ignore][trailing] non-zero trailing bits. It permits //! to [translate] symbols. It permits to use [non-padded][`NoPad`] encodings. //! And it also permits to [decode][decode_concat] concatenated padded inputs. //! However, it does not permit to ignore characters. This has to be done in a //! preprocessing stage, as it is done in the [binary]. Support in the library //! may be added in future versions. //! //! # Migration //! //! The [changelog] describes the changes between v1 and v2. Here are the //! migration steps for common usage: //! //! | v1 | v2 | //! | --------------------------- | --------------------------- | //! | `use data_encoding::baseNN` | `use data_encoding::BASENN` | //! | `baseNN::function` | `BASENN.method` | //! | `baseNN::function_nopad` | `BASENN.no_pad().method` | //! //! [`Builder`]: struct.Builder.html //! [`NoPad`]: struct.NoPad.html //! [`Padded`]: struct.Padded.html //! [RFC4648]: https://tools.ietf.org/html/rfc4648 //! [base16]: constant.HEXUPPER.html //! [base32]: constant.BASE32.html //! [base32hex]: constant.BASE32HEX.html //! [base64]: constant.BASE64.html //! [base64url]: constant.BASE64URL.html //! [binary]: https://crates.io/crates/data-encoding-bin //! [canonical]: https://tools.ietf.org/html/rfc4648#section-3.5 //! [changelog]: https://github.com/ia0/data-encoding/blob/master/lib/CHANGELOG.md //! [constants]: index.html#constants //! [crate]: https://crates.io/crates/data-encoding //! [decode_concat]: struct.Padded.html#method.decode_concat //! [github]: https://github.com/ia0/data-encoding //! [`no_pad`]: struct.Padded.html#method.no_pad //! [trailing]: struct.Builder.html#method.ignore_trailing_bits //! [translate]: struct.Builder.html#method.translate #![warn(unused_results, missing_docs)] /// Decoding error kind #[derive(Debug, Copy, Clone, PartialEq, Eq)] pub enum DecodeKind { /// Invalid length Length, /// Invalid symbol Symbol, /// Non-zero trailing bits Trailing, /// Invalid padding length Padding, } /// Decoding error #[derive(Debug, Copy, Clone, PartialEq, Eq)] pub struct DecodeError { /// Error position pub position: usize, /// Error kind pub kind: DecodeKind, } impl std::error::Error for DecodeError { fn description(&self) -> &str { match self.kind { DecodeKind::Length => "invalid length", DecodeKind::Symbol => "invalid symbol", DecodeKind::Trailing => "non-zero trailing bits", DecodeKind::Padding => "invalid padding length", } } } impl std::fmt::Display for DecodeError { fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result { use std::error::Error; write!(f, "{} at {}", self.description(), self.position) } } macro_rules! check { ($e: expr, $c: expr) => { if !$c { return Err($e); } }; } fn div_ceil(x: usize, m: usize) -> usize { (x + m - 1) / m } fn floor(x: usize, m: usize) -> usize { x / m * m } unsafe fn chunk_unchecked(x: &[u8], n: usize, i: usize) -> &[u8] { debug_assert!((i + 1) * n <= x.len()); let ptr = x.as_ptr().offset((n * i) as isize); std::slice::from_raw_parts(ptr, n) } unsafe fn chunk_mut_unchecked(x: &mut [u8], n: usize, i: usize) -> &mut [u8] { debug_assert!((i + 1) * n <= x.len()); let ptr = x.as_mut_ptr().offset((n * i) as isize); std::slice::from_raw_parts_mut(ptr, n) } trait Base: Copy { fn bit(&self) -> usize; fn msb(&self) -> bool; } macro_rules! make { ($val: expr, $msb: ident, $lsb: ident) => { #[derive(Copy, Clone)] struct $msb; impl Base for $msb { fn bit(&self) -> usize { $val } fn msb(&self) -> bool { true } } #[derive(Copy, Clone)] struct $lsb; impl Base for $lsb { fn bit(&self) -> usize { $val } fn msb(&self) -> bool { false } } }; } make!(1, M1, L1); make!(2, M2, L2); make!(3, M3, L3); make!(4, M4, L4); make!(5, M5, L5); make!(6, M6, L6); macro_rules! dispatch { ($fun: ident; $bit: expr, $msb: expr, $($arg: expr),*) => { match ($bit, $msb) { (1, true) => $fun(M1, $($arg),*), (2, true) => $fun(M2, $($arg),*), (3, true) => $fun(M3, $($arg),*), (4, true) => $fun(M4, $($arg),*), (5, true) => $fun(M5, $($arg),*), (6, true) => $fun(M6, $($arg),*), (1, false) => $fun(L1, $($arg),*), (2, false) => $fun(L2, $($arg),*), (3, false) => $fun(L3, $($arg),*), (4, false) => $fun(L4, $($arg),*), (5, false) => $fun(L5, $($arg),*), (6, false) => $fun(L6, $($arg),*), _ => unreachable!(), } }; } fn order(msb: bool, n: usize, i: usize) -> usize { if msb { n - 1 - i } else { i } } fn enc(bit: usize) -> usize { match bit { 1 | 2 | 4 => 1, 3 | 6 => 3, 5 => 5, _ => unreachable!(), } } fn dec(bit: usize) -> usize { enc(bit) * 8 / bit } fn encode_block<B: Base>(base: B, symbols: &[u8; 256], input: &[u8], output: &mut [u8]) { let bit = base.bit(); let msb = base.msb(); let mut x = 0u64; for i in 0 .. input.len() { x |= (input[i] as u64) << 8 * order(msb, enc(bit), i); } for i in 0 .. output.len() { let y = x >> bit * order(msb, dec(bit), i); output[i] = symbols[y as usize % 256]; } } fn encode_mut<B: Base>(base: B, symbols: &[u8; 256], input: &[u8], output: &mut [u8]) { let enc = enc(base.bit()); let dec = dec(base.bit()); let n = input.len() / enc; for i in 0 .. n { let input = unsafe { chunk_unchecked(input, enc, i) }; let output = unsafe { chunk_mut_unchecked(output, dec, i) }; encode_block(base, symbols, input, output); } encode_block(base, symbols, &input[enc * n ..], &mut output[dec * n ..]); } fn decode_block<B: Base>(base: B, values: &[u8; 256], input: &[u8], output: &mut [u8]) -> Result<(), usize> { let bit = base.bit(); let msb = base.msb(); let mut x = 0u64; for j in 0 .. input.len() { let y = values[input[j] as usize]; check!(j, y < 1 << bit); x |= (y as u64) << bit * order(msb, dec(bit), j); } for j in 0 .. output.len() { output[j] = (x >> 8 * order(msb, enc(bit), j)) as u8; } Ok(()) } fn decode_mut<B: Base>(base: B, values: &[u8; 256], input: &[u8], output: &mut [u8]) -> Result<(), usize> { let enc = enc(base.bit()); let dec = dec(base.bit()); let n = input.len() / dec; for i in 0 .. n { let input = unsafe { chunk_unchecked(input, dec, i) }; let output = unsafe { chunk_mut_unchecked(output, enc, i) }; decode_block(base, values, input, output).map_err(|e| dec * i + e)?; } decode_block(base, values, &input[dec * n ..], &mut output[enc * n ..]) .map_err(|e| dec * n + e) } fn check_trail<B: Base>(base: B, ctb: bool, values: &[u8; 256], input: &[u8]) -> Result<(), ()> { if !ctb { return Ok(()) } let trail = base.bit() * input.len() % 8; if trail == 0 { return Ok(()) } let mut mask = (1 << trail) - 1; if !base.msb() { mask <<= base.bit() - trail; } check!((), values[input[input.len() - 1] as usize] & mask == 0); Ok(()) } fn check_pad<B: Base>(base: B, pad: u8, input: &[u8]) -> Result<usize, usize> { let bit = base.bit(); debug_assert_eq!(input.len(), dec(bit)); let count = input.iter().rev().take_while(|&x| *x == pad).count(); let len = input.len() - count; check!(len, len > 0 && bit * len % 8 < bit); Ok(len) } macro_rules! make_array { ($name: ident, $len: expr) => { impl std::ops::Deref for $name { type Target = [u8; $len]; fn deref(&self) -> &Self::Target { &self.0 } } impl std::ops::DerefMut for $name { fn deref_mut(&mut self) -> &mut Self::Target { &mut self.0 } } impl Clone for $name { fn clone(&self) -> Self { *self } } impl Copy for $name { } impl std::fmt::Debug for $name { fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result { <&[u8] as std::fmt::Debug>::fmt(&(&self.0 as &[u8]), f) } } impl PartialEq for $name { fn eq(&self, other: &Self) -> bool { &self.0 as &[u8] == &other.0 as &[u8] } } impl Eq for $name { } }; } /// Convenience wrapper for `[u8; 128]` /// /// Behaves as `[u8; 128]` through `Deref` and `DerefMut`, but also /// implements `Clone` and other traits. pub struct Array128([u8; 128]); make_array!(Array128, 128); struct Array256([u8; 256]); make_array!(Array256, 256); /// Order in which bits are read from a byte /// /// # Examples /// /// In the following example, we can see that a base with the /// `MostSignificantFirst` bit-order has the most significant bit first in the /// encoded output. In particular, the output is in the same order as the bits /// in the byte. The opposite happens with the `LeastSignificantFirst` /// bit-order. The least significant bit is first and the output is in the /// reverse order. /// /// ```rust /// use data_encoding::Builder; /// let mut builder = Builder::new(b"01"); /// let msb = builder.no_pad().unwrap(); /// let lsb = builder.least_significant_bit_first().no_pad().unwrap(); /// assert_eq!(msb.encode(&[0b01010011]), "01010011"); /// assert_eq!(lsb.encode(&[0b01010011]), "11001010"); /// ``` #[derive(Debug, Copy, Clone, PartialEq, Eq)] pub enum BitOrder { /// Most significant bit first /// /// This is the most common and most intuitive bit-order. In particular, /// this is the bit-order used by [RFC4648] and thus the usual hexadecimal, /// base64, base32, base64url, and base32hex encodings. This is the default /// bit-order when [building](struct.Builder.html) a base. /// /// [RFC4648]: https://tools.ietf.org/html/rfc4648 MostSignificantFirst, /// Least significant bit first /// /// # Examples /// /// Here is how one would implement the [DNSCurve] base32 encoding: /// /// ```rust /// use data_encoding::Builder; /// let dns_curve = Builder::new(b"0123456789bcdfghjklmnpqrstuvwxyz") /// .translate(b"BCDFGHJKLMNPQRSTUVWXYZ", b"bcdfghjklmnpqrstuvwxyz") /// .least_significant_bit_first().no_pad().unwrap(); /// assert_eq!(dns_curve.encode(&[0x64, 0x88]), "4321"); /// assert_eq!(dns_curve.decode(b"4321").unwrap(), vec![0x64, 0x88]); /// ``` /// /// [DNSCurve]: https://dnscurve.org/in-implement.html LeastSignificantFirst, } use BitOrder::*; /// Base-conversion encoding (without padding) /// /// # Theory /// /// The main idea of a [base-conversion] encoding is to see `[u8]` as numbers /// written in little-endian base256 and convert them in another little-endian /// base. For performance reasons, this crate restricts this other base to be of /// size 2 (binary), 4 (base4), 8 (octal), 16 (hexadecimal), 32 (base32), or 64 /// (base64). The converted number is written as `[u8]` although it doesn't use /// all the 256 possible values of `u8`. This crate encodes to ASCII, so only /// values smaller than 128 are allowed. /// /// More precisely, we need the following elements: /// /// - The bit-width N: 1 for binary, 2 for base4, 3 for octal, 4 for /// hexadecimal, 5 for base32, and 6 for base64 /// - The [bit-order](enum.BitOrder.html): most or least significant bit first /// - The symbols function S from [0, 2<sup>N</sup>) (called values and written /// `uN`) to symbols (represented as `u8` although only ASCII symbols are /// allowed, i.e. smaller than 128) /// - The values partial function V from ASCII to [0, 2<sup>N</sup>), i.e. from /// `u8` to `uN` /// - Whether trailing bits are checked: trailing bits are leading zeros in /// theory, but since numbers are little-endian they come last /// /// For the encoding to be correct (i.e. encoding then decoding gives back the /// initial input), V(S(i)) must be defined and equal to i for all i in [0, /// 2<sup>N</sup>). For the encoding to be [canonical][canonical] (i.e. /// different inputs decode to different outputs), trailing bits must be checked /// and if V(i) is defined then S(V(i)) is equal to i for all i. /// /// Encoding and decoding are given by the following pipeline: /// /// ```text /// [u8] <--1--> [[bit; 8]] <--2--> [[bit; N]] <--3--> [uN] <--4--> [u8] /// 1: Map bit-order between each u8 and [bit; 8] /// 2: Base conversion between base 2^8 and base 2^N (check trailing bits) /// 3: Map bit-order between each [bit; N] and [uN] /// 4: Map symbols/values between each uN and u8 (values must be defined) /// ``` /// /// # Practice /// /// ```rust /// use data_encoding::Builder; /// let binary = Builder::new(b"01").no_pad().unwrap(); /// let octal = Builder::new(b"01234567").no_pad().unwrap(); /// let hexadecimal = Builder::new(b"0123456789abcdef").no_pad().unwrap(); /// assert_eq!(binary.encode(b"Bit"), "010000100110100101110100"); /// assert_eq!(octal.encode(b"Bit"), "20464564"); /// assert_eq!(hexadecimal.encode(b"Bit"), "426974"); /// ``` /// /// The `binary` base has 2 symbols `0` and `1` with value 0 and 1 respectively. /// The `octal` base has 8 symbols `0` to `7` with value 0 to 7. The /// `hexadecimal` base has 16 symbols `0` to `9` and `a` to `f` with value 0 to /// 15. The following diagram gives the idea of how encoding works in the /// previous example (note that we can actually write such diagram only because /// the bit-order is most significant first): /// /// ```text /// [ octal] | 2 : 0 : 4 : 6 : 4 : 5 : 6 : 4 | /// [ binary] |0 1 0 0 0 0 1 0|0 1 1 0 1 0 0 1|0 1 1 1 0 1 0 0| /// [hexadecimal] | 4 : 2 | 6 : 9 | 7 : 4 | /// ^-- LSB ^-- MSB /// ``` /// /// Note that in theory, these little-endian numbers are read from right to left /// (the most significant bit is at the right). Since leading zeros are /// meaningless (in our usual decimal notation 0123 is the same as 123), it /// explains why trailing bits must be zero. Trailing bits may occur when the /// bit-width of a base does not divide 8. Only binary, base4, and hexadecimal /// don't have trailing bits issues. So let's consider octal and base64, which /// have trailing bits in similar circumstances: /// /// ```rust /// use data_encoding::{BASE64, Builder}; /// let octal = Builder::new(b"01234567").no_pad().unwrap(); /// assert_eq!(BASE64.no_pad().encode(b"B"), "Qg"); /// assert_eq!(octal.encode(b"B"), "204"); /// ``` /// /// We have the following diagram, where the base64 values are written between /// parentheses: /// /// ```text /// [base64] | Q(16) : g(32) : [has 4 zero trailing bits] /// [ octal] | 2 : 0 : 4 : [has 1 zero trailing bit ] /// |0 1 0 0 0 0 1 0|0 0 0 0 /// [ ascii] | B | /// ^-^-^-^-- leading zeros / trailing bits /// ``` /// /// [base-conversion]: https://en.wikipedia.org/wiki/Positional_notation#Base_conversion /// [canonical]: https://tools.ietf.org/html/rfc4648#section-3.5 #[derive(Debug, Copy, Clone, PartialEq, Eq)] pub struct NoPad { sym: Array256, val: Array256, bit: u8, msb: bool, ctb: bool, } impl NoPad { fn bit(&self) -> usize { self.bit as usize } /// Returns the encoded length of an input of length `len` /// /// See [`encode_mut`] for when to use it. /// /// [`encode_mut`]: struct.NoPad.html#method.encode_mut pub fn encode_len(&self, len: usize) -> usize { div_ceil(8 * len, self.bit()) } /// Encodes `input` in `output` /// /// # Panics /// /// Panics if `output`'s length does not match the result of [`encode_len`] /// for `input`'s length. /// /// # Examples /// /// ```rust /// # use data_encoding::BASE64; /// # let mut buffer = vec![0; 100]; /// # let base64 = BASE64.no_pad(); /// # let input = b"Hello world"; /// let output = &mut buffer[0 .. base64.encode_len(input.len())]; /// base64.encode_mut(input, output); /// # assert_eq!(output, b"SGVsbG8gd29ybGQ"); /// ``` /// /// [`encode_len`]: struct.NoPad.html#method.encode_len pub fn encode_mut(&self, input: &[u8], output: &mut [u8]) { assert_eq!(output.len(), self.encode_len(input.len())); dispatch!(encode_mut; self.bit(), self.msb, &self.sym, input, output) } /// Returns encoded `input` /// /// # Examples /// /// ```rust /// use data_encoding::BASE64; /// assert_eq!(BASE64.no_pad().encode(b"Hello world"), "SGVsbG8gd29ybGQ"); /// ``` pub fn encode(&self, input: &[u8]) -> String { let mut output = vec![0u8; self.encode_len(input.len())]; self.encode_mut(input, &mut output); unsafe { String::from_utf8_unchecked(output) } } /// Returns the decoded length of an input of length `len` /// /// See [`decode_mut`] for when to use it. /// /// # Errors /// /// Returns an error if `len` is invalid. The error kind is [`Length`] and /// the error [position] is the greatest valid length smaller than `len`. /// /// [`decode_mut`]: struct.NoPad.html#method.decode_mut /// [`Length`]: enum.DecodeKind.html#variant.Length /// [position]: struct.DecodeError.html#structfield.position pub fn decode_len(&self, len: usize) -> Result<usize, DecodeError> { let bit = self.bit(); let trail = bit * len % 8; check!(DecodeError { position: len - trail / bit, kind: DecodeKind::Length }, trail < bit); Ok(bit * len / 8) } /// Decodes `input` in `output` /// /// # Panics /// /// Panics if `output`'s length does not match the result of [`decode_len`] /// for `input`'s length. Also panics if `decode_len` fails for `input`'s /// length. /// /// # Errors /// /// Returns an error if `input` is invalid. The error kind can be [`Symbol`] /// or [`Trailing`]. /// /// # Examples /// /// ```rust /// # use data_encoding::BASE64; /// # let mut buffer = vec![0; 100]; /// # let base64 = BASE64.no_pad(); /// # let input = b"SGVsbG8gd29ybGQ"; /// let output = &mut buffer[0 .. base64.decode_len(input.len()).unwrap()]; /// base64.decode_mut(input, output).unwrap(); /// # assert_eq!(output, b"Hello world"); /// ``` /// /// [`decode_len`]: struct.NoPad.html#method.decode_len /// [`Symbol`]: enum.DecodeKind.html#variant.Symbol /// [`Trailing`]: enum.DecodeKind.html#variant.Trailing pub fn decode_mut(&self, input: &[u8], output: &mut [u8]) -> Result<(), DecodeError> { assert_eq!(output.len(), self.decode_len(input.len()).unwrap()); dispatch!(decode_mut; self.bit(), self.msb, &self.val, input, output) .map_err(|pos| DecodeError { position: pos, kind: DecodeKind::Symbol })?; dispatch!(check_trail; self.bit(), self.msb, self.ctb, &self.val, input) .map_err(|()| DecodeError { position: input.len() - 1, kind: DecodeKind::Trailing })?; Ok(()) } /// Returns decoded `input` /// /// # Errors /// /// Returns an error if `input` is invalid. The error kind can be /// [`Length`], [`Symbol`], or [`Trailing`]. /// /// # Examples /// /// ```rust /// use data_encoding::BASE64; /// assert_eq!(BASE64.no_pad().decode(b"SGVsbG8gd29ybGQ").unwrap(), /// b"Hello world"); /// ``` /// /// [`Length`]: enum.DecodeKind.html#variant.Length /// [`Symbol`]: enum.DecodeKind.html#variant.Symbol /// [`Trailing`]: enum.DecodeKind.html#variant.Trailing pub fn decode(&self, input: &[u8]) -> Result<Vec<u8>, DecodeError> { let mut output = vec![0u8; self.decode_len(input.len())?]; self.decode_mut(input, &mut output)?; Ok(output) } /// Returns the bit-width pub fn bit_width(&self) -> usize { self.bit() } /// Returns the bit-order pub fn bit_order(&self) -> BitOrder { if self.msb { MostSignificantFirst } else { LeastSignificantFirst } } /// Returns the symbols pub fn symbols(&self) -> &str { let symbols = &self.sym[0 .. 1 << self.bit()]; unsafe { std::str::from_utf8_unchecked(symbols) } } /// Returns the non-canonical symbols /// /// Non-canonical symbols are ASCII characters i for which V(i) is defined /// but S(V(i)) is different from i. In other words, these characters cannot /// be produced by the encoding function but are still recognized by the /// decoding function and behave as the canonical symbol of the same value. /// /// The result `(from, to)` has the following properties: /// /// - `from` and `to` are ASCII and have the same length /// - All non-canonical symbols are listed in `from` in ascending order /// - `from[i]` is a non-canonical symbol that behaves as `to[i]` for all i /// /// # Examples /// /// ```rust /// let (from, to) = data_encoding::HEXLOWER_PERMISSIVE.translate(); /// assert_eq!((from.as_str(), to.as_str()), ("ABCDEF", "abcdef")); /// ``` pub fn translate(&self) -> (String, String) { let mut from = vec![]; let mut to = vec![]; for i in 0 .. 128 { if self.val[i] == 128 { continue; } let canonical = self.sym[self.val[i] as usize]; if i as u8 == canonical { continue; } from.push(i as u8); to.push(canonical); } let from = unsafe { String::from_utf8_unchecked(from) }; let to = unsafe { String::from_utf8_unchecked(to) }; (from, to) } /// Whether trailing bits are checked /// /// Returns `None` for bases that don't need to check trailing bits (like /// base2, base4, and base16). Otherwise, for bases that would need it (like /// base8, base32, and base64), returns whether trailing bits are checked. pub fn check_trailing_bits(&self) -> Option<bool> { if 8 % self.bit() == 0 { None } else { Some(self.ctb) } } } /// Padded base-conversion encoding /// /// The padded encoding extends the [base-conversion] encoding. This is only /// useful for octal, base32, and base64. And for those bases, it is only useful /// if the length of the data to encode is not known in advance. /// /// # Theory /// /// Bases for which the bit-width N does not divide 8 may not concatenate /// encoded data. This comes from the fact that it is not possible to make the /// difference between trailing bits and encoding bits. Padding solves this /// issue by adding a new character (which is not a symbol) to discriminate /// between trailing bits and encoding bits. The idea is to work by blocks of /// lcm(8, N) bits, where lcm(8, N) is the least common multiple of 8 and N. /// When such block is not complete, it is padded. /// /// # Practice /// /// For octal and base64, lcm(8, 3) == lcm(8, 6) == 24 bits or 3 bytes. For /// base32, lcm(8, 5) is 40 bits or 5 bytes. Let's consider octal and base64: /// /// ```rust /// use data_encoding::{BASE64, Builder}; /// let octal = Builder::new(b"01234567").pad(b'=').padded().unwrap(); /// // We start encoding but we only have "B" for now. /// assert_eq!(BASE64.encode(b"B"), "Qg=="); /// assert_eq!(octal.encode(b"B"), "204====="); /// // Now we have "it". /// assert_eq!(BASE64.encode(b"it"), "aXQ="); /// assert_eq!(octal.encode(b"it"), "322720=="); /// // By concatenating everything, we may decode the original data. /// assert_eq!(BASE64.decode_concat(b"Qg==aXQ=").unwrap(), b"Bit"); /// assert_eq!(octal.decode_concat(b"204=====322720==").unwrap(), b"Bit"); /// ``` /// /// We have the following diagrams: /// /// ```text /// [base64] | Q(16) : g(32) : = : = | /// [ octal] | 2 : 0 : 4 : = : = : = : = : = | /// |0 1 0 0 0 0 1 0|. . . . . . . .|. . . . . . . .| /// [ ascii] | B | end of block aligned --^ /// ^-- beginning of block aligned /// /// [base64] | a(26) : X(23) : Q(16) : = | /// [ octal] | 3 : 2 : 2 : 7 : 2 : 0 : = : = | /// |0 1 1 0 1 0 0 1|0 1 1 1 0 1 0 0|. . . . . . . .| /// [ ascii] | i | t | /// ``` /// /// [base-conversion]: struct.NoPad.html #[derive(Debug, Copy, Clone, PartialEq, Eq)] pub struct Padded { no_pad: NoPad, pad: u8, } impl Padded { /// Returns the encoded length of an input of length `len` /// /// See [`encode_mut`] for when to use it. /// /// [`encode_mut`]: struct.Padded.html#method.encode_mut pub fn encode_len(&self, len: usize) -> usize { let bit = self.no_pad.bit(); div_ceil(len, enc(bit)) * dec(bit) } /// Encodes `input` in `output`. /// /// # Panics /// /// Panics if `output`'s length does not match the result of [`encode_len`] /// for `input`'s length. /// /// # Examples /// /// ```rust /// use data_encoding::BASE64; /// # let mut buffer = vec![0; 100]; /// let input = b"Hello world"; /// let output = &mut buffer[0 .. BASE64.encode_len(input.len())]; /// BASE64.encode_mut(input, output); /// assert_eq!(output, b"SGVsbG8gd29ybGQ="); /// ``` /// /// [`encode_len`]: struct.Padded.html#method.encode_len pub fn encode_mut(&self, input: &[u8], output: &mut [u8]) { assert_eq!(output.len(), self.encode_len(input.len())); let last = self.no_pad.encode_len(input.len()); self.no_pad.encode_mut(input, &mut output[0 .. last]); for i in output[last ..].iter_mut() { *i = self.pad; } } /// Returns encoded `input` /// /// # Examples /// /// ```rust /// use data_encoding::BASE64; /// assert_eq!(BASE64.encode(b"Hello world"), "SGVsbG8gd29ybGQ="); /// ``` pub fn encode(&self, input: &[u8]) -> String { let mut output = vec![0u8; self.encode_len(input.len())]; self.encode_mut(input, &mut output); unsafe { String::from_utf8_unchecked(output) } } /// Returns the decoded length of an input of length `len` /// /// See [`decode_mut`] for when to use it. /// /// # Errors /// /// Returns an error if `len` is invalid. The error kind is [`Length`] and /// the error [position] is the greatest valid length smaller than `len`. /// /// [`decode_mut`]: struct.Padded.html#method.decode_mut /// [`Length`]: enum.DecodeKind.html#variant.Length /// [position]: struct.DecodeError.html#structfield.position pub fn decode_len(&self, len: usize) -> Result<usize, DecodeError> { let bit = self.no_pad.bit(); check!(DecodeError { position: floor(len, dec(bit)), kind: DecodeKind::Length }, len % dec(bit) == 0); Ok(len / dec(bit) * enc(bit)) } /// Decodes `input` in `output` /// /// Returns the length of the decoded output. This length may be smaller /// than output's length if the input is padded. The output bytes after the /// returned length are not initialized and should not be read. /// /// # Panics /// /// Panics if `output`'s length does not match the result of [`decode_len`] /// for `input`'s length. Also panics if `decode_len` fails for `input`'s /// length. /// /// # Errors /// /// Returns an error if `input` is invalid. The error kind can be /// [`Symbol`], [`Trailing`], or [`Padding`]. /// /// # Examples /// /// ```rust /// use data_encoding::BASE64; /// # let mut buffer = vec![0; 100]; /// let input = b"SGVsbG8gd29ybGQ="; /// let output = &mut buffer[0 .. BASE64.decode_len(input.len()).unwrap()]; /// let len = BASE64.decode_mut(input, output).unwrap(); /// assert_eq!(&output[0 .. len], b"Hello world"); /// ``` /// /// [`decode_len`]: struct.Padded.html#method.decode_len /// [`Symbol`]: enum.DecodeKind.html#variant.Symbol /// [`Trailing`]: enum.DecodeKind.html#variant.Trailing /// [`Padding`]: enum.DecodeKind.html#variant.Padding pub fn decode_mut(&self, input: &[u8], output: &mut [u8]) -> Result<usize, DecodeError> { if input.len() == 0 { return Ok(0); } assert_eq!(output.len(), self.decode_len(input.len()).unwrap()); let dec = dec(self.no_pad.bit()); let ilen = input.len() - dec; let irem = dispatch!(check_pad; self.no_pad.bit(), self.no_pad.msb, self.pad, &input[ilen ..]) .map_err(|e| DecodeError { position: ilen + e, kind: DecodeKind::Padding })?; let olen = self.no_pad.decode_len(ilen + irem).unwrap(); self.no_pad.decode_mut(&input[.. ilen + irem], &mut output[.. olen])?; Ok(olen) } /// Returns decoded `input` /// /// # Errors /// /// Returns an error if `input` is invalid. The error kind can be /// [`Length`], [`Symbol`], [`Trailing`], or [`Padding`]. /// /// # Examples /// /// ```rust /// use data_encoding::BASE64; /// assert_eq!(BASE64.decode(b"SGVsbG8gd29ybGQ=").unwrap(), b"Hello world"); /// ``` /// /// [`Length`]: enum.DecodeKind.html#variant.Length /// [`Symbol`]: enum.DecodeKind.html#variant.Symbol /// [`Trailing`]: enum.DecodeKind.html#variant.Trailing /// [`Padding`]: enum.DecodeKind.html#variant.Padding pub fn decode(&self, input: &[u8]) -> Result<Vec<u8>, DecodeError> { let mut output = vec![0u8; self.decode_len(input.len())?]; let len = self.decode_mut(input, &mut output)?; output.truncate(len); Ok(output) } /// Decodes concatenated `input` in `output` /// /// Returns the length of the decoded output. This length may be smaller /// than output's length if the input contained padding. The output bytes /// after the returned length are not initialized and should not be read. /// /// # Panics /// /// Panics if `output`'s length does not match the result of [`decode_len`] /// for `input`'s length. Also panics if `decode_len` fails for `input`'s /// length. /// /// # Errors /// /// Returns an error if `input` is invalid. The error kind can be /// [`Symbol`], [`Trailing`], or [`Padding`]. /// /// # Examples /// /// ```rust /// use data_encoding::BASE64; /// # let mut buffer = vec![0; 100]; /// let input = b"SGVsbA==byB3b3JsZA=="; /// let output = &mut buffer[0 .. BASE64.decode_len(input.len()).unwrap()]; /// let len = BASE64.decode_concat_mut(input, output).unwrap(); /// assert_eq!(&output[0 .. len], b"Hello world"); /// ``` /// /// [`decode_len`]: struct.Padded.html#method.decode_len /// [`Symbol`]: enum.DecodeKind.html#variant.Symbol /// [`Trailing`]: enum.DecodeKind.html#variant.Trailing /// [`Padding`]: enum.DecodeKind.html#variant.Padding pub fn decode_concat_mut(&self, input: &[u8], output: &mut [u8]) -> Result<usize, DecodeError> { assert_eq!(output.len(), self.decode_len(input.len()).unwrap()); let bit = self.no_pad.bit(); let enc = enc(bit); let dec = dec(bit); let mut inpos = 0; let mut outpos = 0; let mut outend = output.len(); while inpos < input.len() { let ret = self.no_pad.decode_mut( &input[inpos ..], &mut output[outpos .. outend]); match ret { Ok(()) => break, Err(err) => { debug_assert_eq!(err.kind, DecodeKind::Symbol); inpos += err.position / dec * dec; outpos += err.position / dec * enc; }, } let inlen = dispatch!(check_pad; self.no_pad.bit(), self.no_pad.msb, self.pad, &input[inpos .. inpos + dec]) .map_err(|e| DecodeError { position: inpos + e, kind: DecodeKind::Padding })?; let outlen = self.no_pad.decode_len(inlen).unwrap(); self.no_pad.decode_mut(&input[inpos .. inpos + inlen], &mut output[outpos .. outpos + outlen]) .map_err(|mut e| { e.position += inpos; e })?; inpos += dec; outpos += outlen; outend -= enc - outlen; } Ok(outend) } /// Returns decoded concatenated `input` /// /// # Errors /// /// Returns an error if `input` is invalid. The error kind can be /// [`Length`], [`Symbol`], [`Trailing`], or [`Padding`]. /// /// # Examples /// /// ```rust /// use data_encoding::BASE64; /// assert_eq!(BASE64.decode_concat(b"SGVsbA==byB3b3JsZA==").unwrap(), /// b"Hello world"); /// ``` /// /// [`Length`]: enum.DecodeKind.html#variant.Length /// [`Symbol`]: enum.DecodeKind.html#variant.Symbol /// [`Trailing`]: enum.DecodeKind.html#variant.Trailing /// [`Padding`]: enum.DecodeKind.html#variant.Padding pub fn decode_concat(&self, input: &[u8]) -> Result<Vec<u8>, DecodeError> { let mut output = vec![0u8; self.decode_len(input.len())?]; let len = self.decode_concat_mut(input, &mut output)?; output.truncate(len); Ok(output) } /// Returns the associated base-conversion encoding /// /// # Examples /// /// ```rust /// use data_encoding::BASE64; /// assert_eq!(BASE64.encode(b"Helo"), "SGVsbw=="); /// assert_eq!(BASE64.no_pad().encode(b"Helo"), "SGVsbw"); /// ``` pub fn no_pad(&self) -> &NoPad { &self.no_pad } /// Returns the padding character pub fn padding(&self) -> u8 { self.pad } } /// Base representation /// /// Convenience methods are provided to edit the fields, although they may be /// manually edited. /// /// # Examples /// /// See the [lower-case hexadecimal][1], [upper-case hexadecimal][2], /// [lower-case permissive hexadecimal][3], [base32], [base32hex], [base64], and /// [base64url] encodings. /// /// [1]: constant.HEXLOWER.html /// [2]: constant.HEXUPPER.html /// [3]: constant.HEXLOWER_PERMISSIVE.html /// [base32]: constant.BASE32.html /// [base32hex]: constant.BASE32HEX.html /// [base64]: constant.BASE64.html /// [base64url]: constant.BASE64URL.html #[derive(Debug, Clone)] pub struct Builder { /// Symbols /// /// The number of symbols must be 2, 4, 8, 16, 32, or 64. Symbols must be /// ASCII characters (smaller than 128) and they must be unique. pub symbols: Box<[u8]>, /// Values /// /// A value of 128 means that the index is not a symbol. In other words, if /// `values[s] != 128` then `s` is a symbol (canonical if /// `symbols[values[s]]` is equal to `s`) and `values[s]` is its value. /// /// Default is the inverse of symbols. pub values: Box<Array128>, /// Bit-order /// /// Default is most significant bit first. pub bit_order: BitOrder, /// Padding /// /// Default is no padding. pub padding: Option<u8>, /// Whether trailing bits are checked /// /// Default is to check trailing bits. This field is ignored when /// unnecessary (i.e. for base2, base4, and base16). pub check_trailing_bits: bool, } #[derive(Debug, Copy, Clone)] enum BuilderErrorImpl { BadSize, BadSym(u8), BadVal(u8), BadPad(Option<u8>), } use BuilderErrorImpl::*; /// Base building error #[derive(Debug, Copy, Clone)] pub struct BuilderError(BuilderErrorImpl); impl std::fmt::Display for BuilderError { fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result { match self.0 { BadSize => write!(f, "Invalid number of symbols"), BadSym(s) => write!(f, "Non-ascii symbol {:#x}", s), BadVal(s) => write!(f, "Invalid value for {:?}", s as char), BadPad(Some(s)) if s < 128 => write!(f, "Padding symbol conflict"), BadPad(Some(pad)) => write!(f, "Non-ascii padding {:#x}", pad), BadPad(None) => write!(f, "Unnecessary or missing padding"), } } } impl std::error::Error for BuilderError { fn description(&self) -> &str { match self.0 { BadSize => "invalid number of symbols", BadSym(_) => "non-ascii symbol", BadVal(_) => "invalid value", BadPad(Some(s)) if s < 128 => "padding symbol conflict", BadPad(Some(_)) => "non-ascii padding", BadPad(None) => "unnecessary or missing padding", } } } impl Builder { fn bit(&self) -> Result<u8, BuilderError> { match self.symbols.len() { 2 => Ok(1), 4 => Ok(2), 8 => Ok(3), 16 => Ok(4), 32 => Ok(5), 64 => Ok(6), _ => Err(BuilderError(BadSize)), } } fn check(&self) -> Result<(), BuilderError> { let bit = self.bit()?; let even = 8 % bit == 0; check!(BuilderError(BadPad(None)), self.padding.is_none() || !even); for v in 0 .. self.symbols.len() { let s = self.symbols[v]; check!(BuilderError(BadSym(s)), s < 128); check!(BuilderError(BadVal(s)), self.values[s as usize] == v as u8); } for s in 0 .. self.values.len() { if self.values[s] == 128 { continue; } check!(BuilderError(BadVal(s as u8)), self.values[s] < 1 << bit); } if let Some(pad) = self.padding { check!(BuilderError(BadPad(Some(pad))), pad < 128); for s in 0 .. self.values.len() { if self.values[s] == 128 { continue; } check!(BuilderError(BadPad(Some(pad))), pad != s as u8); } } Ok(()) } fn no_pad_unchecked(&self) -> NoPad { let bit = self.bit().unwrap(); let mut base = NoPad { sym: Array256([0; 256]), val: Array256([128; 256]), bit: bit, msb: self.bit_order == MostSignificantFirst, ctb: 8 % bit != 0 && self.check_trailing_bits, }; for i in 0 .. base.sym.len() { base.sym[i] = self.symbols[i % self.symbols.len()]; } for i in 0 .. self.values.len() { base.val[i] = self.values[i]; } base } /// Returns a canonical base representation for `symbols` /// /// By default, the base representation does not have non-canonical symbols. /// It does not have padding. It is most significant bit first. And it /// checks the trailing bits if necessary. /// /// # Errors /// /// Errors are silently ignored. In other words, if a symbol is not ASCII, /// if there are duplicate symbols, or if the number of symbols is not a /// power of 2 smaller than 128, then no errors are signaled. However, when /// building the base with [`no_pad`] or [`padded`], if the base /// representation is still invalid, an error will be returned. /// /// [`no_pad`]: struct.Builder.html#method.no_pad /// [`padded`]: struct.Builder.html#method.padded pub fn new(symbols: &[u8]) -> Builder { let mut builder = Builder { symbols: symbols.to_vec().into_boxed_slice(), values: Box::new(Array128([128; 128])), bit_order: MostSignificantFirst, padding: None, check_trailing_bits: true, }; for v in 0 .. symbols.len() { if symbols[v] >= 128 { continue; } builder.values[symbols[v] as usize] = v as u8; } builder } /// Sets padding pub fn pad(&mut self, pad: u8) -> &mut Builder { self.padding = Some(pad); self } /// Adds non-canonical symbols /// /// For all i, `from[i]` is given the same value as `to[i]`. /// /// By default there are only canonical symbols. Non-canonical symbols /// cannot be produced by encoding functions, but they are recognized by /// decoding functions. They behave as the canonical symbol of the same /// value. /// /// # Panics /// /// Panics if `from` and `to` don't have the same length. /// /// # Errors /// /// Errors are silently ignored. If a character in `from` or `to` is not /// ASCII then the pair is skipped. If the character in `from` is already a /// symbol it is overwritten. If the character in `to` is not a symbol, /// `from` is reset. /// /// # Examples /// /// ```rust /// # use data_encoding::Builder; /// let base = Builder::new(b"0123456789abcdef") /// .translate(b"ABCDEF", b"abcdef").no_pad().unwrap(); /// assert_eq!(base.decode(b"Bb").unwrap(), vec![0xbb]); /// ``` pub fn translate(&mut self, from: &[u8], to: &[u8]) -> &mut Builder { assert_eq!(from.len(), to.len()); for i in 0 .. from.len() { if from[i] >= 128 || to[i] >= 128 { continue; } self.values[from[i] as usize] = self.values[to[i] as usize]; } self } /// Sets bit-order to least significant bit first pub fn least_significant_bit_first(&mut self) -> &mut Builder { self.bit_order = LeastSignificantFirst; self } /// Ignores trailing bits pub fn ignore_trailing_bits(&mut self) -> &mut Builder { self.check_trailing_bits = false; self } /// Returns the represented base-conversion encoding /// /// # Errors /// /// Returns an error if the base representation is invalid. pub fn no_pad(&self) -> Result<NoPad, BuilderError> { check!(BuilderError(BadPad(None)), self.padding.is_none()); self.check()?; Ok(self.no_pad_unchecked()) } /// Returns the represented padded base-conversion encoding /// /// # Errors /// /// Returns an error if the base representation is invalid. pub fn padded(&self) -> Result<Padded, BuilderError> { let pad = self.padding.ok_or(BuilderError(BadPad(None)))?; self.check()?; Ok(Padded { no_pad: self.no_pad_unchecked(), pad: pad }) } } impl<'a> From<&'a NoPad> for Builder { fn from(no_pad: &NoPad) -> Builder { let mut builder = Builder { symbols: no_pad.symbols().as_bytes().to_vec().into_boxed_slice(), values: Box::new(Array128([0; 128])), bit_order: no_pad.bit_order(), padding: None, check_trailing_bits: no_pad.ctb, }; builder.values.copy_from_slice(&no_pad.val[0 .. 128]); builder } } impl<'a> From<&'a Padded> for Builder { fn from(padded: &Padded) -> Builder { let mut builder = Builder::from(&padded.no_pad); builder.padding = Some(padded.pad); builder } } const X_: u8 = 128; macro_rules! make_val { ($($v: expr),*) => { [ X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, $($v),*, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, ] }; } macro_rules! make_sym { (7; $($s: expr),*) => { [ $($s),*, $($s),*, ] }; (6; $($s: expr),*) => { make_sym!(7; $($s),*, $($s),*) }; (5; $($s: expr),*) => { make_sym!(6; $($s),*, $($s),*) }; (4; $($s: expr),*) => { make_sym!(5; $($s),*, $($s),*) }; } macro_rules! make_base { ($b: tt; $($v: expr),*; $($s: expr),*;) => { NoPad { sym: Array256(make_sym!($b; $($s),*)), val: Array256(make_val!($($v),*)), bit: $b, msb: true, ctb: 8 % $b != 0, } }; ($p: expr; $b: tt; $($v: expr),*; $($s: expr),*;) => { Padded { no_pad: make_base!($b; $($v),*; $($s),*;), pad: $p, } }; } /// Lower-case hexadecimal encoding /// /// This encoding is a static version of: /// /// ```rust /// # use data_encoding::{Builder, HEXLOWER}; /// assert_eq!(HEXLOWER, &Builder::new(b"0123456789abcdef").no_pad().unwrap()); /// ``` /// /// # Examples /// /// ```rust /// use data_encoding::HEXLOWER; /// let deadbeef = vec![0xde, 0xad, 0xbe, 0xef]; /// assert_eq!(HEXLOWER.decode(b"deadbeef").unwrap(), deadbeef); /// assert_eq!(HEXLOWER.encode(&deadbeef), "deadbeef"); /// ``` pub const HEXLOWER: &'static NoPad = HEXLOWER_IMPL; const HEXLOWER_IMPL: &'static NoPad = &make_base!{ 4; X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, 0 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, 10, 11, 12, 13, 14, 15, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_; b'0', b'1', b'2', b'3', b'4', b'5', b'6', b'7', b'8', b'9', b'a', b'b', b'c', b'd', b'e', b'f'; }; /// RFC4648 hex encoding (upper-case hexadecimal encoding) /// /// This encoding is a static version of: /// /// ```rust /// # use data_encoding::{Builder, HEXUPPER}; /// assert_eq!(HEXUPPER, &Builder::new(b"0123456789ABCDEF").no_pad().unwrap()); /// ``` /// /// It is compliant with [RFC4648] and known as "base16" or "hex". /// /// # Examples /// /// ```rust /// use data_encoding::HEXUPPER; /// let deadbeef = vec![0xde, 0xad, 0xbe, 0xef]; /// assert_eq!(HEXUPPER.decode(b"DEADBEEF").unwrap(), deadbeef); /// assert_eq!(HEXUPPER.encode(&deadbeef), "DEADBEEF"); /// ``` /// /// [RFC4648]: https://tools.ietf.org/html/rfc4648#section-8 pub const HEXUPPER: &'static NoPad = HEXUPPER_IMPL; const HEXUPPER_IMPL: &'static NoPad = &make_base!{ 4; X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, 0 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , X_, X_, X_, X_, X_, X_, X_, 10, 11, 12, 13, 14, 15, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_; b'0', b'1', b'2', b'3', b'4', b'5', b'6', b'7', b'8', b'9', b'A', b'B', b'C', b'D', b'E', b'F'; }; /// Lower-case permissive hexadecimal encoding /// /// This encoding is a static version of: /// /// ```rust /// # use data_encoding::{Builder, HEXLOWER_PERMISSIVE}; /// let mut base = Builder::new(b"0123456789abcdef") /// .translate(b"ABCDEF", b"abcdef").no_pad().unwrap(); /// assert_eq!(HEXLOWER_PERMISSIVE, &base); /// ``` /// /// # Examples /// /// ```rust /// use data_encoding::HEXLOWER_PERMISSIVE; /// let deadbeef = vec![0xde, 0xad, 0xbe, 0xef]; /// assert_eq!(HEXLOWER_PERMISSIVE.decode(b"DeadBeef").unwrap(), deadbeef); /// assert_eq!(HEXLOWER_PERMISSIVE.encode(&deadbeef), "deadbeef"); /// ``` /// /// You can also define a shorter name: /// /// ```rust /// use data_encoding::{HEXLOWER_PERMISSIVE, NoPad}; /// const HEX: &'static NoPad = HEXLOWER_PERMISSIVE; /// ``` pub const HEXLOWER_PERMISSIVE: &'static NoPad = HEXLOWER_PERMISSIVE_IMPL; const HEXLOWER_PERMISSIVE_IMPL: &'static NoPad = &make_base!{ 4; X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, 0 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , X_, X_, X_, X_, X_, X_, X_, 10, 11, 12, 13, 14, 15, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, 10, 11, 12, 13, 14, 15, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_; b'0', b'1', b'2', b'3', b'4', b'5', b'6', b'7', b'8', b'9', b'a', b'b', b'c', b'd', b'e', b'f'; }; /// RFC4648 base32 encoding /// /// This encoding is a static version of: /// /// ```rust /// # use data_encoding::{Builder, BASE32}; /// assert_eq!(BASE32, &Builder::new(b"ABCDEFGHIJKLMNOPQRSTUVWXYZ234567") /// .pad(b'=').padded().unwrap()); /// ``` /// /// It is conformant with [RFC4648]. /// /// [RFC4648]: https://tools.ietf.org/html/rfc4648#section-6 pub const BASE32: &'static Padded = BASE32_IMPL; const BASE32_IMPL: &'static Padded = &make_base!{ b'='; 5; X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, 26, 27, 28, 29, 30, 31, X_, X_, X_, X_, X_, X_, X_, X_, X_, 0_, 1_, 2_, 3_, 4_, 5_, 6_, 7_, 8_, 9_, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_; b'A', b'B', b'C', b'D', b'E', b'F', b'G', b'H', b'I', b'J', b'K', b'L', b'M', b'N', b'O', b'P', b'Q', b'R', b'S', b'T', b'U', b'V', b'W', b'X', b'Y', b'Z', b'2', b'3', b'4', b'5', b'6', b'7'; }; /// RFC4648 base32hex encoding /// /// This encoding is a static version of: /// /// ```rust /// # use data_encoding::{Builder, BASE32HEX}; /// assert_eq!(BASE32HEX, &Builder::new(b"0123456789ABCDEFGHIJKLMNOPQRSTUV") /// .pad(b'=').padded().unwrap()); /// ``` /// /// It is conformant with [RFC4648]. /// /// [RFC4648]: https://tools.ietf.org/html/rfc4648#section-7 pub const BASE32HEX: &'static Padded = BASE32HEX_IMPL; const BASE32HEX_IMPL: &'static Padded = &make_base!{ b'='; 5; X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, 0_, 1_, 2_, 3_, 4_, 5_, 6_, 7_, 8_, 9_, X_, X_, X_, X_, X_, X_, X_, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_; b'0', b'1', b'2', b'3', b'4', b'5', b'6', b'7', b'8', b'9', b'A', b'B', b'C', b'D', b'E', b'F', b'G', b'H', b'I', b'J', b'K', b'L', b'M', b'N', b'O', b'P', b'Q', b'R', b'S', b'T', b'U', b'V'; }; /// RFC4648 base64 encoding /// /// This encoding is a static version of: /// /// ```rust /// # use data_encoding::{Builder, BASE64}; /// assert_eq!(BASE64, &Builder::new( /// b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/") /// .pad(b'=').padded().unwrap()); /// ``` /// /// It is conformant with [RFC4648]. /// /// [RFC4648]: https://tools.ietf.org/html/rfc4648#section-4 pub const BASE64: &'static Padded = BASE64_IMPL; const BASE64_IMPL: &'static Padded = &make_base!{ b'='; 6; X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, 62, X_, X_, X_, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, X_, X_, X_, X_, X_, X_, X_, 0_, 1_, 2_, 3_, 4_, 5_, 6_, 7_, 8_, 9_, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, X_, X_, X_, X_, X_, X_, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, X_, X_, X_, X_, X_; b'A', b'B', b'C', b'D', b'E', b'F', b'G', b'H', b'I', b'J', b'K', b'L', b'M', b'N', b'O', b'P', b'Q', b'R', b'S', b'T', b'U', b'V', b'W', b'X', b'Y', b'Z', b'a', b'b', b'c', b'd', b'e', b'f', b'g', b'h', b'i', b'j', b'k', b'l', b'm', b'n', b'o', b'p', b'q', b'r', b's', b't', b'u', b'v', b'w', b'x', b'y', b'z', b'0', b'1', b'2', b'3', b'4', b'5', b'6', b'7', b'8', b'9', b'+', b'/'; }; /// RFC4648 base64url encoding /// /// This encoding is a static version of: /// /// ```rust /// # use data_encoding::{Builder, BASE64URL}; /// assert_eq!(BASE64URL, &Builder::new( /// b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_") /// .pad(b'=').padded().unwrap()); /// ``` /// /// It is conformant with [RFC4648]. /// /// [RFC4648]: https://tools.ietf.org/html/rfc4648#section-5 pub const BASE64URL: &'static Padded = BASE64URL_IMPL; const BASE64URL_IMPL: &'static Padded = &make_base!{ b'='; 6; X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, X_, 62, X_, X_, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, X_, X_, X_, X_, X_, X_, X_, 0_, 1_, 2_, 3_, 4_, 5_, 6_, 7_, 8_, 9_, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, X_, X_, X_, X_, 63, X_, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, X_, X_, X_, X_, X_; b'A', b'B', b'C', b'D', b'E', b'F', b'G', b'H', b'I', b'J', b'K', b'L', b'M', b'N', b'O', b'P', b'Q', b'R', b'S', b'T', b'U', b'V', b'W', b'X', b'Y', b'Z', b'a', b'b', b'c', b'd', b'e', b'f', b'g', b'h', b'i', b'j', b'k', b'l', b'm', b'n', b'o', b'p', b'q', b'r', b's', b't', b'u', b'v', b'w', b'x', b'y', b'z', b'0', b'1', b'2', b'3', b'4', b'5', b'6', b'7', b'8', b'9', b'-', b'_'; };