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//! # Configs //! //! There isn't just one type of Base64; that would be too simple. You need to choose a character //! set (standard or URL-safe), padding suffix (yes/no), and line wrap (line length, line ending). //! The `Config` struct encapsulates this info. There are some common configs included: `STANDARD`, //! `MIME`, etc. You can also make your own `Config` if needed. //! //! The functions that don't have `config` in the name (e.g. `encode()` and `decode()`) use the //! `STANDARD` config . //! //! The functions that write to a slice (the ones that end in `_slice`) are generally the fastest //! because they don't need to resize anything. If it fits in your workflow and you care about //! performance, keep using the same buffer (growing as need be) and use the `_slice` methods for //! the best performance. //! //! # Encoding //! //! Several different encoding functions are available to you depending on your desire for //! convenience vs performance. //! //! | Function | Output | Allocates | //! | ----------------------- | ---------------------------- | ------------------------------ | //! | `encode` | Returns a new `String` | Always | //! | `encode_config` | Returns a new `String` | Always | //! | `encode_config_buf` | Appends to provided `String` | Only if `String` needs to grow | //! | `encode_config_slice` | Writes to provided `&[u8]` | Never | //! //! All of the encoding functions that take a `Config` will pad, line wrap, etc, as per the config. //! //! # Decoding //! //! Just as for encoding, there are different decoding functions available. //! //! Note that all decode functions that take a config will allocate a copy of the input if you //! specify a config that requires whitespace to be stripped. If you care about speed, don't use //! formats that line wrap and then require whitespace stripping. //! //! | Function | Output | Allocates | //! | ----------------------- | ----------------------------- | ------------------------------ | //! | `decode` | Returns a new `Vec<u8>` | Always | //! | `decode_config` | Returns a new `Vec<u8>` | Always | //! | `decode_config_buf` | Appends to provided `Vec<u8>` | Only if `Vec` needs to grow | //! | `decode_config_slice` | Writes to provided `&[u8]` | Never | //! //! Unlike encoding, where all possible input is valid, decoding can fail (see `DecodeError`). //! //! Input can be invalid because it has invalid characters or invalid padding. (No padding at all is //! valid, but excess padding is not.) //! //! Whitespace in the input is invalid unless `strip_whitespace` is enabled in the `Config` used. //! //! # Panics //! //! If length calculations result in overflowing `usize`, a panic will result. //! //! The `_slice` flavors of encode or decode will panic if the provided output slice is too small, #![deny( missing_docs, trivial_casts, trivial_numeric_casts, unused_extern_crates, unused_import_braces, unused_results, variant_size_differences, warnings )] extern crate byteorder; mod chunked_encoder; pub mod display; mod line_wrap; mod tables; use line_wrap::{line_wrap, line_wrap_parameters}; mod encode; pub use encode::{encode, encode_config, encode_config_buf, encode_config_slice}; mod decode; pub use decode::{decode, decode_config, decode_config_buf, decode_config_slice, DecodeError}; #[cfg(test)] mod tests; /// Available encoding character sets #[derive(Clone, Copy, Debug)] pub enum CharacterSet { /// The standard character set (uses `+` and `/`) Standard, /// The URL safe character set (uses `-` and `_`) UrlSafe, /// The `crypt(3)` character set (uses `./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz`) Crypt, } impl CharacterSet { fn encode_table(&self) -> &'static [u8; 64] { match *self { CharacterSet::Standard => tables::STANDARD_ENCODE, CharacterSet::UrlSafe => tables::URL_SAFE_ENCODE, CharacterSet::Crypt => tables::CRYPT_ENCODE, } } fn decode_table(&self) -> &'static [u8; 256] { match *self { CharacterSet::Standard => tables::STANDARD_DECODE, CharacterSet::UrlSafe => tables::URL_SAFE_DECODE, CharacterSet::Crypt => tables::CRYPT_DECODE, } } } /// Line ending used in optional line wrapping. #[derive(Clone, Copy, Debug)] pub enum LineEnding { /// Unix-style \n LF, /// Windows-style \r\n CRLF, } impl LineEnding { fn len(&self) -> usize { match *self { LineEnding::LF => 1, LineEnding::CRLF => 2, } } } /// Line wrap configuration. #[derive(Clone, Copy, Debug)] pub enum LineWrap { /// Don't wrap. NoWrap, /// Wrap lines with the specified length and line ending. The length must be > 0. Wrap(usize, LineEnding), } /// Contains configuration parameters for base64 encoding #[derive(Clone, Copy, Debug)] pub struct Config { /// Character set to use char_set: CharacterSet, /// True to pad output with `=` characters pad: bool, /// Remove whitespace before decoding, at the cost of an allocation. Whitespace is defined /// according to POSIX-locale `isspace`, meaning \n \r \f \t \v and space. strip_whitespace: bool, /// ADT signifying whether to linewrap output, and if so by how many characters and with what /// ending line_wrap: LineWrap, } impl Config { /// Create a new `Config`. pub fn new( char_set: CharacterSet, pad: bool, strip_whitespace: bool, input_line_wrap: LineWrap, ) -> Config { let line_wrap = match input_line_wrap { LineWrap::Wrap(0, _) => LineWrap::NoWrap, _ => input_line_wrap, }; Config { char_set, pad, strip_whitespace, line_wrap, } } } /// Standard character set with padding. pub const STANDARD: Config = Config { char_set: CharacterSet::Standard, pad: true, strip_whitespace: false, line_wrap: LineWrap::NoWrap, }; /// Standard character set without padding. pub const STANDARD_NO_PAD: Config = Config { char_set: CharacterSet::Standard, pad: false, strip_whitespace: false, line_wrap: LineWrap::NoWrap, }; /// As per standards for MIME encoded messages pub const MIME: Config = Config { char_set: CharacterSet::Standard, pad: true, strip_whitespace: true, line_wrap: LineWrap::Wrap(76, LineEnding::CRLF), }; /// URL-safe character set with padding pub const URL_SAFE: Config = Config { char_set: CharacterSet::UrlSafe, pad: true, strip_whitespace: false, line_wrap: LineWrap::NoWrap, }; /// URL-safe character set without padding pub const URL_SAFE_NO_PAD: Config = Config { char_set: CharacterSet::UrlSafe, pad: false, strip_whitespace: false, line_wrap: LineWrap::NoWrap, }; /// As per `crypt(3)` requirements pub const CRYPT: Config = Config { char_set: CharacterSet::Crypt, pad: false, strip_whitespace: false, line_wrap: LineWrap::NoWrap, };