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 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 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478
use std; use {ByteCount, Eos, Error, Result}; use combinator::{EncoderChain, Last, Length, MapErr, MapFrom, MaxBytes, Optional, Padding, PreEncode, Repeat, Slice, TryMapFrom, WithPrefix}; /// This trait allows for encoding items into a byte sequence incrementally. pub trait Encode { /// The type of items to be encoded. type Item; /// Encodes the items in the encoder and writes the encoded bytes to the given buffer. /// /// It returns the number of bytes written to the given buffer. /// /// If the encoded bytes are larger than the length of `buf`, /// the encoder must consume as many bytes in the buffer as possible. /// /// The completion of the encoding can be detected by using `is_idle` method. /// /// If `self.is_idle()` returns `false` but the number of written bytes in the last `encode` invocation /// is smaller than the length of `buf`, it means the encoder has been suspended its work in any reasons. /// In that case the encoder may require some instructions from clients to resume the work, /// but its concrete method is beyond the scope of this trait. /// /// The encoded bytes that could not be written to the given buffer is held by /// the encoder until the next invocation of the `encode` method. /// /// # Errors /// /// Encoders return the following kinds of errors as necessary: /// - `ErrorKind::InvalidInput`: /// - An item that the encoder could not encode was passed /// - `ErrorKind::UnexpectedEos`: /// - The output byte stream has reached the end in the middle of an encoding process /// - `ErrorKind::Other`: /// - Other errors has occurred fn encode(&mut self, buf: &mut [u8], eos: Eos) -> Result<usize>; /// Tries to start encoding the given item. /// /// If the encoder has no items to be encoded and the passed item is valid, it must accept the item. /// /// # Errors /// /// - `ErrorKind::EncoderFull`: /// - The encoder currently cannot accept any more items /// - `ErrorKind::InvalidInput`: /// - An invalid item was passed /// - `ErrorKind::Other`: /// - Other errors has occurred fn start_encoding(&mut self, item: Self::Item) -> Result<()>; /// Returns `true` if there are no items to be encoded in the encoder, otherwise `false`. fn is_idle(&self) -> bool; /// Returns the number of bytes required to encode all the items in the encoder. /// /// If there are no items to be encoded, the encoder must return `ByteCount::Finite(0)`. fn requiring_bytes(&self) -> ByteCount; } impl<'a, E: ?Sized + Encode> Encode for &'a mut E { type Item = E::Item; fn encode(&mut self, buf: &mut [u8], eos: Eos) -> Result<usize> { (**self).encode(buf, eos) } fn start_encoding(&mut self, item: Self::Item) -> Result<()> { (**self).start_encoding(item) } fn requiring_bytes(&self) -> ByteCount { (**self).requiring_bytes() } fn is_idle(&self) -> bool { (**self).is_idle() } } impl<E: ?Sized + Encode> Encode for Box<E> { type Item = E::Item; fn encode(&mut self, buf: &mut [u8], eos: Eos) -> Result<usize> { (**self).encode(buf, eos) } fn start_encoding(&mut self, item: Self::Item) -> Result<()> { (**self).start_encoding(item) } fn requiring_bytes(&self) -> ByteCount { (**self).requiring_bytes() } fn is_idle(&self) -> bool { (**self).is_idle() } } /// This trait indicates that the encoder always known the exact bytes required to encode remaining items. pub trait ExactBytesEncode: Encode { /// Returns the exact number of bytes required to encode all the items remaining in the encoder. fn exact_requiring_bytes(&self) -> u64; } impl<E: ?Sized + ExactBytesEncode> ExactBytesEncode for Box<E> { fn exact_requiring_bytes(&self) -> u64 { (**self).exact_requiring_bytes() } } /// An extension of `Encode` trait. pub trait EncodeExt: Encode + Sized { /// Creates a new encoder instance that has the given initial item. /// /// # Examples /// /// ``` /// use bytecodec::{Encode, EncodeExt}; /// use bytecodec::fixnum::U8Encoder; /// use bytecodec::io::IoEncodeExt; /// /// let mut output = Vec::new(); /// let mut encoder = U8Encoder::with_item(7).unwrap(); /// encoder.encode_all(&mut output).unwrap(); /// assert_eq!(output, [7]); /// assert!(encoder.is_idle()); /// ``` fn with_item(item: Self::Item) -> Result<Self> where Self: Default, { let mut this = Self::default(); track!(this.start_encoding(item))?; Ok(this) } /// Creates an encoder for modifying encoding errors produced by `self`. /// /// # Examples /// /// The following code shows the idiomatic way to track encoding errors: /// /// ``` /// extern crate bytecodec; /// #[macro_use] /// extern crate trackable; /// /// use bytecodec::{Encode, EncodeExt, Eos}; /// use bytecodec::fixnum::U8Encoder; /// /// # fn main() { /// let encoder = U8Encoder::with_item(7).unwrap(); /// let mut encoder = encoder.map_err(|e| track!(e, "oops!")); // or track_err!(encoder, "oops!") /// let error = track!(encoder.encode(&mut [][..], Eos::new(true))).err().unwrap(); /// /// assert_eq!(error.to_string(), "\ /// UnexpectedEos (cause; assertion failed: `!eos.is_reached()`; \ /// buf.len()=0, size=0, self.offset=0, b.as_ref().len()=1) /// HISTORY: /// [0] at src/bytes.rs:54 /// [1] at src/fixnum.rs:113 /// [2] at src/encode.rs:11 -- oops! /// [3] at src/encode.rs:12\n"); /// # } /// ``` fn map_err<F, E>(self, f: F) -> MapErr<Self, F, E> where F: Fn(Error) -> E, Error: From<E>, { MapErr::new(self, f) } /// Creates an encoder that converts items into ones that /// suited to the `self` encoder by calling the given function. /// /// # Examples /// /// ``` /// use bytecodec::{Encode, EncodeExt}; /// use bytecodec::fixnum::U8Encoder; /// use bytecodec::io::IoEncodeExt; /// /// let mut output = Vec::new(); /// let mut encoder = U8Encoder::new().map_from(|s: String| s.len() as u8); /// let item = "Hello World!".to_owned(); /// encoder.start_encoding(item).unwrap(); /// encoder.encode_all(&mut output).unwrap(); /// assert_eq!(output, [12]); /// ``` fn map_from<T, F>(self, f: F) -> MapFrom<Self, T, F> where F: Fn(T) -> Self::Item, { MapFrom::new(self, f) } /// Creates an encoder that tries to convert items into ones that /// suited to the `self` encoder by calling the given function. /// /// # Examples /// /// ``` /// extern crate bytecodec; /// #[macro_use] /// extern crate trackable; /// /// use bytecodec::{Encode, EncodeExt, ErrorKind, Result}; /// use bytecodec::fixnum::U8Encoder; /// use bytecodec::io::IoEncodeExt; /// /// # fn main() { /// let mut output = Vec::new(); /// let mut encoder = U8Encoder::new().try_map_from(|s: String| -> Result<_> { /// track_assert!(s.len() <= 0xFF, ErrorKind::InvalidInput); /// Ok(s.len() as u8) /// }); /// let item = "Hello World!".to_owned(); /// encoder.start_encoding(item).unwrap(); /// encoder.encode_all(&mut output).unwrap(); /// assert_eq!(output, [12]); /// # } /// ``` fn try_map_from<T, E, F>(self, f: F) -> TryMapFrom<Self, T, E, F> where F: Fn(T) -> std::result::Result<Self::Item, E>, Error: From<E>, { TryMapFrom::new(self, f) } /// Takes two encoders and creates a new encoder that encodes both items in sequence. /// /// Chains are started by calling `StartEncoderChain::chain` method. /// /// # Examples /// /// Encodes a length-prefixed UTF-8 string: /// /// ``` /// use bytecodec::{Encode, EncodeExt, StartEncoderChain}; /// use bytecodec::bytes::Utf8Encoder; /// use bytecodec::fixnum::U8Encoder; /// use bytecodec::io::IoEncodeExt; /// /// let mut output = Vec::new(); /// let mut encoder = StartEncoderChain /// .chain(U8Encoder::new()) /// .chain(Utf8Encoder::new()) /// .map_from(|s: String| (s.len() as u8, s)); /// encoder.start_encoding("foo".to_owned()).unwrap(); /// encoder.encode_all(&mut output).unwrap(); /// assert_eq!(output, b"\x03foo"); /// ``` fn chain<E: Encode>(self, other: E) -> EncoderChain<Self, E, Self::Item> { EncoderChain::new(self, other) } /// Creates an encoder that represents an optional encoder. /// /// It takes `Option<Self::Item>` items. /// If `Some(_)` is passed as an argument for `start_encoding` method, it will be encoded as ordinally. /// On the other hand, if `None` is passed, it will be ignored completely. /// /// # Examples /// /// ``` /// use bytecodec::{Encode, EncodeExt}; /// use bytecodec::fixnum::U8Encoder; /// use bytecodec::io::IoEncodeExt; /// /// let mut output = Vec::new(); /// let mut encoder = U8Encoder::new().optional(); /// /// encoder.start_encoding(None).unwrap(); /// encoder.encode_all(&mut output).unwrap(); /// /// encoder.start_encoding(Some(9)).unwrap(); /// encoder.encode_all(&mut output).unwrap(); /// /// assert_eq!(output, [9]); /// ``` fn optional(self) -> Optional<Self> { Optional::new(self) } /// Creates an encoder that will fail if the number of encoded bytes of an item exceeds `n`. /// /// # Examples /// /// ``` /// use bytecodec::{Encode, EncodeExt, ErrorKind}; /// use bytecodec::bytes::Utf8Encoder; /// use bytecodec::io::IoEncodeExt; /// /// let mut output = Vec::new(); /// let mut encoder = Utf8Encoder::new().max_bytes(3); /// /// encoder.start_encoding("foo").unwrap(); // OK /// encoder.encode_all(&mut output).unwrap(); /// assert_eq!(output, b"foo"); /// /// encoder.start_encoding("hello").unwrap(); // Error /// let error = encoder.encode_all(&mut output).err().unwrap(); /// assert_eq!(*error.kind(), ErrorKind::InvalidInput); /// ``` fn max_bytes(self, n: u64) -> MaxBytes<Self> { MaxBytes::new(self, n) } /// Creates an encoder that required to encode each item exactly at the specified number of bytes. /// /// # Examples /// /// ``` /// use bytecodec::{Encode, EncodeExt, ErrorKind}; /// use bytecodec::bytes::Utf8Encoder; /// use bytecodec::io::IoEncodeExt; /// /// let mut output = Vec::new(); /// let mut encoder = Utf8Encoder::new().length(3); /// encoder.start_encoding("hey").unwrap(); // OK /// encoder.encode_all(&mut output).unwrap(); /// assert_eq!(output, b"hey"); /// /// let mut encoder = Utf8Encoder::new().length(3); /// encoder.start_encoding("hello").unwrap(); // Error (too long) /// let error = encoder.encode_all(&mut output).err().unwrap(); /// assert_eq!(*error.kind(), ErrorKind::UnexpectedEos); /// /// let mut encoder = Utf8Encoder::new().length(3); /// encoder.start_encoding("hi").unwrap(); // Error (too short) /// let error = encoder.encode_all(&mut output).err().unwrap(); /// assert_eq!(*error.kind(), ErrorKind::InvalidInput); /// ``` fn length(self, n: u64) -> Length<Self> { Length::new(self, n) } /// Creates an encoder that keeps writing padding byte until it reaches EOS /// after encoding of `self`'s item has been completed. /// /// # Examples /// /// ``` /// use bytecodec::{Encode, EncodeExt, ErrorKind}; /// use bytecodec::fixnum::U8Encoder; /// use bytecodec::io::IoEncodeExt; /// /// let mut output = Vec::new(); /// let mut encoder = U8Encoder::new().padding(9).length(3); /// encoder.start_encoding(3).unwrap(); /// encoder.encode_all(&mut output).unwrap(); /// assert_eq!(output, [3, 9, 9]); /// ``` fn padding(self, padding_byte: u8) -> Padding<Self> { Padding::new(self, padding_byte) } /// Creates an encoder that repeats encoding of `Self::Item`. /// /// # Examples /// /// ``` /// use bytecodec::{Encode, EncodeExt, ErrorKind}; /// use bytecodec::fixnum::U8Encoder; /// use bytecodec::io::IoEncodeExt; /// /// let mut output = Vec::new(); /// let mut encoder = U8Encoder::new().repeat(); /// encoder.start_encoding(0..4).unwrap(); /// encoder.encode_all(&mut output).unwrap(); /// assert_eq!(output, [0, 1, 2, 3]); /// ``` fn repeat<I>(self) -> Repeat<Self, I> where I: Iterator<Item = Self::Item>, { Repeat::new(self) } /// Creates an encoder that has a prefixed item encoded by `E`. /// /// # Examples /// /// Encodes a length prefixed UTF-8 string: /// /// ``` /// use bytecodec::{Encode, EncodeExt, ExactBytesEncode}; /// use bytecodec::bytes::Utf8Encoder; /// use bytecodec::fixnum::U8Encoder; /// use bytecodec::io::IoEncodeExt; /// /// let mut output = Vec::new(); /// let mut encoder = /// Utf8Encoder::new().with_prefix(U8Encoder::new(), |body| body.exact_requiring_bytes() as u8); /// encoder.start_encoding("foo").unwrap(); /// encoder.encode_all(&mut output).unwrap(); /// assert_eq!(output, [3, b'f', b'o', b'o']); /// ``` fn with_prefix<E, F>(self, prefix: E, f: F) -> WithPrefix<Self, E, F> where F: Fn(&Self) -> E::Item, E: Encode, { WithPrefix::new(self, prefix, f) } /// Creates an encoder that pre-encodes items when `start_encoding` method is called. /// /// Although the number of memory copies increases, /// pre-encoding will enable to acquire the exact size of encoded items. /// /// # Examples /// /// ``` /// use bytecodec::{Encode, EncodeExt, ExactBytesEncode}; /// use bytecodec::fixnum::U8Encoder; /// use bytecodec::io::IoEncodeExt; /// /// let mut output = Vec::new(); /// let mut encoder = /// U8Encoder::new() /// .repeat() /// .pre_encode() /// .with_prefix(U8Encoder::new(), |body| body.exact_requiring_bytes() as u8); /// /// encoder.start_encoding(0..3).unwrap(); /// encoder.encode_all(&mut output).unwrap(); /// assert_eq!(output, [3, 0, 1, 2]); /// ``` fn pre_encode(self) -> PreEncode<Self> { PreEncode::new(self) } /// Creates an encoder that makes it possible to slice the encoded byte sequence in arbitrary units. /// /// Slicing encoded byte sequences makes it easier to multiplex them into a single sequence. /// /// # Examples /// /// ``` /// use bytecodec::{Encode, EncodeExt, Eos}; /// use bytecodec::bytes::Utf8Encoder; /// /// let mut encoder = Utf8Encoder::new().slice(); /// encoder.start_encoding("foobarbaz").unwrap(); /// /// let eos = Eos::new(true); /// let mut output = [0; 9]; /// let mut offset = 0; /// /// encoder.set_consumable_bytes(3); /// offset += encoder.encode(&mut output[offset..], eos).unwrap(); /// assert_eq!(offset, 3); /// assert_eq!(encoder.is_idle(), false); /// assert_eq!(encoder.consumable_bytes(), 0); /// /// offset += encoder.encode(&mut output[offset..], eos).unwrap(); /// assert_eq!(offset, 3); /// /// encoder.set_consumable_bytes(6); /// offset += encoder.encode(&mut output[offset..], eos).unwrap(); /// assert_eq!(offset, 9); /// assert_eq!(encoder.is_idle(), true); /// assert_eq!(output.as_ref(), b"foobarbaz"); /// ``` fn slice(self) -> Slice<Self> { Slice::new(self) } /// Creates an encoder that cannot accept any more items. fn last(self) -> Last<Self> { Last::new(self) } } impl<T: Encode> EncodeExt for T {}