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Diffstat (limited to 'vendor/encode_unicode/src/decoding_iterators.rs')
| -rw-r--r-- | vendor/encode_unicode/src/decoding_iterators.rs | 494 |
1 files changed, 0 insertions, 494 deletions
diff --git a/vendor/encode_unicode/src/decoding_iterators.rs b/vendor/encode_unicode/src/decoding_iterators.rs deleted file mode 100644 index 4ef4125..0000000 --- a/vendor/encode_unicode/src/decoding_iterators.rs +++ /dev/null @@ -1,494 +0,0 @@ -/* Copyright 2018 The encode_unicode Developers - * - * Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or - * http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or - * http://opensource.org/licenses/MIT>, at your option. This file may not be - * copied, modified, or distributed except according to those terms. - */ - -//! Iterators that turn multiple `u8`s or `u16`s into `Utf*Char`s, but can fail. -//! -//! To be predictable, all errors consume one element each. -//! -//! The iterator adaptors produce neither offset nor element length to work -//! well with other adaptors, -//! while the slice iterators yield both to make more advanced use cases easy. - -use errors::{InvalidUtf8Slice, InvalidUtf16FirstUnit, Utf16PairError}; -use errors::InvalidUtf8Slice::*; -use errors::InvalidUtf8::*; -use errors::InvalidUtf8FirstByte::*; -use errors::InvalidUtf16Slice::*; -use errors::InvalidCodepoint::*; -use errors::Utf16PairError::*; -use utf8_char::Utf8Char; -use utf16_char::Utf16Char; -use traits::U16UtfExt; -extern crate core; -use self::core::borrow::Borrow; -use self::core::fmt::{self, Debug}; -use self::core::iter::Chain; -use self::core::option; - - -/// Decodes UTF-8 characters from a byte iterator into `Utf8Char`s. -/// -/// See [`IterExt::to_utf8chars()`](../trait.IterExt.html#tymethod.to_utf8chars) -/// for examples and error handling. -#[derive(Clone, Default)] -pub struct Utf8CharMerger<B:Borrow<u8>, I:Iterator<Item=B>> { - iter: I, - /// number of bytes that were read before an error was detected - after_err_leftover: u8, - /// stack because it simplifies popping. - after_err_stack: [u8; 3], -} -impl<B:Borrow<u8>, I:Iterator<Item=B>, T:IntoIterator<IntoIter=I,Item=B>> -From<T> for Utf8CharMerger<B, I> { - fn from(t: T) -> Self { - Utf8CharMerger { - iter: t.into_iter(), - after_err_leftover: 0, - after_err_stack: [0; 3], - } - } -} -impl<B:Borrow<u8>, I:Iterator<Item=B>> Utf8CharMerger<B,I> { - /// Extract the inner iterator. - /// - /// If the last item produced by `.next()` was an `Err`, - /// up to three following bytes might be missing. - /// The exact number of missing bytes for each error type should not be relied on. - /// - /// # Examples - /// - /// Three bytes swallowed: - /// ``` - /// # use encode_unicode::IterExt; - /// let mut merger = b"\xf4\xa1\xb2FS".iter().to_utf8chars(); - /// assert!(merger.next().unwrap().is_err()); - /// let mut inner: std::slice::Iter<u8> = merger.into_inner(); - /// assert_eq!(inner.next(), Some(&b'S')); // b'\xa1', b'\xb2' and b'F' disappeared - /// ``` - /// - /// All bytes present: - /// ``` - /// # use encode_unicode::IterExt; - /// let mut merger = b"\xb0FS".iter().to_utf8chars(); - /// assert!(merger.next().unwrap().is_err()); - /// assert_eq!(merger.into_inner().next(), Some(&b'F')); - /// ``` - /// - /// Two bytes missing: - /// ``` - /// # use encode_unicode::IterExt; - /// let mut merger = b"\xe0\x80\x80FS".iter().to_utf8chars(); - /// assert!(merger.next().unwrap().is_err()); - /// assert_eq!(merger.into_inner().next(), Some(&b'F')); - /// ``` - pub fn into_inner(self) -> I { - self.iter - } - - fn save(&mut self, bytes: &[u8;4], len: usize) { - // forget bytes[0] and push the others onto self.after_err_stack (in reverse). - for &after_err in bytes[1..len].iter().rev() { - self.after_err_stack[self.after_err_leftover as usize] = after_err; - self.after_err_leftover += 1; - } - } - /// Reads len-1 bytes into bytes[1..] - fn extra(&mut self, bytes: &mut[u8;4], len: usize) -> Result<(),InvalidUtf8Slice> { - // This is the only function that pushes onto after_err_stack, - // and it checks that all bytes are continuation bytes before fetching the next one. - // Therefore only the last byte retrieved can be a non-continuation byte. - // That last byte is also the last to be retrieved from after_err. - // - // Before this function is called, there has been retrieved at least one byte. - // If that byte was a continuation byte, next() produces an error - // and won't call this function. - // Therefore, we know that after_err is empty at this point. - // This means that we can use self.iter directly, and knows where to start pushing - debug_assert_eq!(self.after_err_leftover, 0, "first: {:#02x}, stack: {:?}", bytes[0], self.after_err_stack); - for i in 1..len { - if let Some(extra) = self.iter.next() { - let extra = *extra.borrow(); - bytes[i] = extra; - if extra & 0b1100_0000 != 0b1000_0000 { - // not a continuation byte - self.save(bytes, i+1); - return Err(InvalidUtf8Slice::Utf8(NotAContinuationByte(i))) - } - } else { - self.save(bytes, i); - return Err(TooShort(len)); - } - } - Ok(()) - } -} -impl<B:Borrow<u8>, I:Iterator<Item=B>> Iterator for Utf8CharMerger<B,I> { - type Item = Result<Utf8Char,InvalidUtf8Slice>; - fn next(&mut self) -> Option<Self::Item> { - let first: u8; - if self.after_err_leftover != 0 { - self.after_err_leftover -= 1; - first = self.after_err_stack[self.after_err_leftover as usize]; - } else if let Some(next) = self.iter.next() { - first = *next.borrow(); - } else { - return None; - } - - unsafe { - let mut bytes = [first, 0, 0, 0]; - let ok = match first { - 0b0000_0000...0b0111_1111 => {/*1 and */Ok(())}, - 0b1100_0010...0b1101_1111 => {//2 and not overlong - self.extra(&mut bytes, 2) // no extra validation required - }, - 0b1110_0000...0b1110_1111 => {//3 - if let Err(e) = self.extra(&mut bytes, 3) { - Err(e) - } else if bytes[0] == 0b1110_0000 && bytes[1] <= 0b10_011111 { - self.save(&bytes, 3); - Err(Utf8(OverLong)) - } else if bytes[0] == 0b1110_1101 && bytes[1] & 0b11_100000 == 0b10_100000 { - self.save(&bytes, 3); - Err(Codepoint(Utf16Reserved)) - } else { - Ok(()) - } - }, - 0b1111_0000...0b1111_0100 => {//4 - if let Err(e) = self.extra(&mut bytes, 4) { - Err(e) - } else if bytes[0] == 0b11110_000 && bytes[1] <= 0b10_001111 { - self.save(&bytes, 4); - Err(InvalidUtf8Slice::Utf8(OverLong)) - } else if bytes[0] == 0b11110_100 && bytes[1] > 0b10_001111 { - self.save(&bytes, 4); - Err(InvalidUtf8Slice::Codepoint(TooHigh)) - } else { - Ok(()) - } - }, - 0b1000_0000...0b1011_1111 => {// continuation byte - Err(Utf8(FirstByte(ContinuationByte))) - }, - 0b1100_0000...0b1100_0001 => {// 2 and overlong - Err(Utf8(OverLong)) - }, - 0b1111_0101...0b1111_0111 => {// 4 and too high codepoint - Err(Codepoint(TooHigh)) - }, - 0b1111_1000...0b1111_1111 => { - Err(Utf8(FirstByte(TooLongSeqence))) - }, - _ => unreachable!("all possible byte values should be covered") - }; - Some(ok.map(|()| Utf8Char::from_array_unchecked(bytes) )) - } - } - fn size_hint(&self) -> (usize,Option<usize>) { - let (iter_min, iter_max) = self.iter.size_hint(); - // cannot be exact, so KISS - let min = iter_min / 4; // don't bother rounding up or accounting for after_err - // handle edge case of max > usize::MAX-3 just in case. - // Using wrapping_add() wouldn't violate any API contract as the trait isn't unsafe. - let max = iter_max.and_then(|max| { - max.checked_add(self.after_err_leftover as usize) - }); - (min, max) - } -} -impl<B:Borrow<u8>, I:Iterator<Item=B>+Debug> Debug for Utf8CharMerger<B,I> { - fn fmt(&self, fmtr: &mut fmt::Formatter) -> fmt::Result { - let mut in_order = [0u8; 3]; - for i in 0..self.after_err_leftover as usize { - in_order[i] = self.after_err_stack[self.after_err_leftover as usize - i - 1]; - } - fmtr.debug_struct("Utf8CharMerger") - .field("buffered", &&in_order[..self.after_err_leftover as usize]) - .field("inner", &self.iter) - .finish() - } -} - - -/// An [`Utf8CharMerger`](struct.Utf8CharMerger.html) that also produces -/// offsets and lengths, but can only iterate over slices. -/// -/// See [`SliceExt::utf8char_indices()`](../trait.SliceExt.html#tymethod.utf8char_indices) -/// for examples and error handling. -#[derive(Clone, Default)] -pub struct Utf8CharDecoder<'a> { - slice: &'a[u8], - index: usize, -} -impl<'a> From<&'a[u8]> for Utf8CharDecoder<'a> { - fn from(s: &[u8]) -> Utf8CharDecoder { - Utf8CharDecoder { slice: s, index: 0 } - } -} -impl<'a> Utf8CharDecoder<'a> { - /// Extract the remainder of the source slice. - /// - /// # Examples - /// - /// Unlike `Utf8CharMerger::into_inner()`, bytes directly after an error - /// are never swallowed: - /// ``` - /// # use encode_unicode::SliceExt; - /// let mut iter = b"\xf4\xa1\xb2FS".utf8char_indices(); - /// assert!(iter.next().unwrap().1.is_err()); - /// assert_eq!(iter.as_slice(), b"\xa1\xb2FS"); - /// ``` - pub fn as_slice(&self) -> &'a[u8] { - &self.slice[self.index..] - } -} -impl<'a> Iterator for Utf8CharDecoder<'a> { - type Item = (usize, Result<Utf8Char,InvalidUtf8Slice>, usize); - fn next(&mut self) -> Option<Self::Item> { - let start = self.index; - match Utf8Char::from_slice_start(&self.slice[self.index..]) { - Ok((u8c, len)) => { - self.index += len; - Some((start, Ok(u8c), len)) - }, - Err(TooShort(1)) => None, - Err(e) => { - self.index += 1; - Some((start, Err(e), 1)) - } - } - } - #[inline] - fn size_hint(&self) -> (usize,Option<usize>) { - let bytes = self.slice.len() - self.index; - // Cannot be exact, so KISS and don't bother rounding up. - // The slice is unlikely be full of 4-byte codepoints, so buffers - // allocated with the lower bound will have to be grown anyway. - (bytes/4, Some(bytes)) - } -} -impl<'a> DoubleEndedIterator for Utf8CharDecoder<'a> { - fn next_back(&mut self) -> Option<Self::Item> { - if self.index < self.slice.len() { - let extras = self.slice.iter() - .rev() - .take_while(|&b| b & 0b1100_0000 == 0b1000_0000 ) - .count(); - let starts = self.slice.len() - (extras+1); - match Utf8Char::from_slice_start(&self.slice[starts..]) { - Ok((u8c,len)) if len == 1+extras => { - self.slice = &self.slice[..starts]; - Some((starts, Ok(u8c), len)) - }, - // This enures errors for every byte in both directions, - // but means overlong and codepoint errors will be turned into - // tooshort errors. - Err(e) if extras == 0 => { - self.slice = &self.slice[..self.slice.len()-1]; - Some((self.slice.len()-1, Err(e), 1)) - }, - _ => { - self.slice = &self.slice[..self.slice.len()-1]; - Some((self.slice.len()-1, Err(Utf8(FirstByte(ContinuationByte))), 1)) - }, - } - } else { - None - } - } -} -impl<'a> Debug for Utf8CharDecoder<'a> { - fn fmt(&self, fmtr: &mut fmt::Formatter) -> fmt::Result { - write!(fmtr, "Utf8CharDecoder {{ bytes[{}..]: {:?} }}", self.index, self.as_slice()) - } -} - - - -/// Decodes UTF-16 characters from a `u16` iterator into `Utf16Char`s. -/// -/// See [`IterExt::to_utf16chars()`](../trait.IterExt.html#tymethod.to_utf16chars) -/// for examples and error handling. -#[derive(Clone, Default)] -pub struct Utf16CharMerger<B:Borrow<u16>, I:Iterator<Item=B>> { - iter: I, - /// Used when a trailing surrogate was expected, the u16 can be any value. - prev: Option<B>, -} -impl<B:Borrow<u16>, I:Iterator<Item=B>, T:IntoIterator<IntoIter=I,Item=B>> -From<T> for Utf16CharMerger<B,I> { - fn from(t: T) -> Self { - Utf16CharMerger { iter: t.into_iter(), prev: None } - } -} -impl<B:Borrow<u16>, I:Iterator<Item=B>> Utf16CharMerger<B,I> { - /// Extract the inner iterator. - /// - /// If the last item produced was an `Err`, the first unit might be missing. - /// - /// # Examples - /// - /// Unit right after an error missing - /// ``` - /// # use encode_unicode::IterExt; - /// # use encode_unicode::error::Utf16PairError; - /// let mut merger = [0xd901, 'F' as u16, 'S' as u16].iter().to_utf16chars(); - /// assert_eq!(merger.next(), Some(Err(Utf16PairError::UnmatchedLeadingSurrogate))); - /// let mut inner: std::slice::Iter<u16> = merger.into_inner(); - /// assert_eq!(inner.next(), Some('S' as u16).as_ref()); // 'F' was consumed by Utf16CharMerger - /// ``` - /// - /// Error that doesn't swallow any units - /// ``` - /// # use encode_unicode::IterExt; - /// # use encode_unicode::error::Utf16PairError; - /// let mut merger = [0xde00, 'F' as u16, 'S' as u16].iter().to_utf16chars(); - /// assert_eq!(merger.next(), Some(Err(Utf16PairError::UnexpectedTrailingSurrogate))); - /// let mut inner: std::slice::Iter<u16> = merger.into_inner(); - /// assert_eq!(inner.next(), Some('F' as u16).as_ref()); // not consumed - /// ``` - pub fn into_inner(self) -> I { - self.iter - } - /// Returns an iterator over the remaining units. - /// Unlike `into_inner()` this will never drop any units. - /// - /// The exact type of the returned iterator should not be depended on. - /// - /// # Examples - /// - /// ``` - /// # use encode_unicode::IterExt; - /// # use encode_unicode::error::Utf16PairError; - /// let slice = [0xd901, 'F' as u16, 'S' as u16]; - /// let mut merger = slice.iter().to_utf16chars(); - /// assert_eq!(merger.next(), Some(Err(Utf16PairError::UnmatchedLeadingSurrogate))); - /// let mut remaining = merger.into_remaining_units(); - /// assert_eq!(remaining.next(), Some('F' as u16).as_ref()); - /// ``` - pub fn into_remaining_units(self) -> Chain<option::IntoIter<B>,I> { - self.prev.into_iter().chain(self.iter) - } -} -impl<B:Borrow<u16>, I:Iterator<Item=B>> Iterator for Utf16CharMerger<B,I> { - type Item = Result<Utf16Char,Utf16PairError>; - fn next(&mut self) -> Option<Self::Item> { - let first = self.prev.take().or_else(|| self.iter.next() ); - first.map(|first| unsafe { - match first.borrow().utf16_needs_extra_unit() { - Ok(false) => Ok(Utf16Char::from_array_unchecked([*first.borrow(), 0])), - Ok(true) => match self.iter.next() { - Some(second) => match second.borrow().utf16_needs_extra_unit() { - Err(InvalidUtf16FirstUnit) => Ok(Utf16Char::from_tuple_unchecked(( - *first.borrow(), - Some(*second.borrow()) - ))), - Ok(_) => { - self.prev = Some(second); - Err(Utf16PairError::UnmatchedLeadingSurrogate) - } - }, - None => Err(Utf16PairError::Incomplete) - }, - Err(InvalidUtf16FirstUnit) => Err(Utf16PairError::UnexpectedTrailingSurrogate), - } - }) - } - fn size_hint(&self) -> (usize,Option<usize>) { - let (iter_min, iter_max) = self.iter.size_hint(); - // cannot be exact, so KISS - let min = iter_min / 2; // don't bother rounding up or accounting for self.prev - let max = match (iter_max, &self.prev) { - (Some(max), &Some(_)) => max.checked_add(1), - (max, _) => max, - }; - (min, max) - } -} -impl<B:Borrow<u16>, I:Iterator<Item=B>+Debug> Debug for Utf16CharMerger<B,I> { - fn fmt(&self, fmtr: &mut fmt::Formatter) -> fmt::Result { - fmtr.debug_struct("Utf16CharMerger") - .field("buffered", &self.prev.as_ref().map(|b| *b.borrow() )) - .field("inner", &self.iter) - .finish() - } -} - - -/// An [`Utf16CharMerger`](struct.Utf16CharMerger.html) that also produces -/// offsets and lengths, but can only iterate over slices. -/// -/// See [`SliceExt::utf16char_indices()`](../trait.SliceExt.html#tymethod.utf16char_indices) -/// for examples and error handling. -#[derive(Clone, Default)] -pub struct Utf16CharDecoder<'a> { - slice: &'a[u16], - index: usize, -} -impl<'a> From<&'a[u16]> for Utf16CharDecoder<'a> { - fn from(s: &'a[u16]) -> Self { - Utf16CharDecoder{ slice: s, index: 0 } - } -} -impl<'a> Utf16CharDecoder<'a> { - /// Extract the remainder of the source slice. - /// - /// # Examples - /// - /// Unlike `Utf16CharMerger::into_inner()`, the unit after an error is never swallowed: - /// ``` - /// # use encode_unicode::SliceExt; - /// # use encode_unicode::error::Utf16PairError; - /// let mut iter = [0xd901, 'F' as u16, 'S' as u16].utf16char_indices(); - /// assert_eq!(iter.next(), Some((0, Err(Utf16PairError::UnmatchedLeadingSurrogate), 1))); - /// assert_eq!(iter.as_slice(), &['F' as u16, 'S' as u16]); - /// ``` - pub fn as_slice(&self) -> &[u16] { - &self.slice[self.index..] - } -} -impl<'a> Iterator for Utf16CharDecoder<'a> { - type Item = (usize,Result<Utf16Char,Utf16PairError>,usize); - #[inline] - fn next(&mut self) -> Option<Self::Item> { - let start = self.index; - match Utf16Char::from_slice_start(self.as_slice()) { - Ok((u16c,len)) => { - self.index += len; - Some((start, Ok(u16c), len)) - }, - Err(EmptySlice) => None, - Err(FirstLowSurrogate) => { - self.index += 1; - Some((start, Err(UnexpectedTrailingSurrogate), 1)) - }, - Err(SecondNotLowSurrogate) => { - self.index += 1; - Some((start, Err(UnmatchedLeadingSurrogate), 1)) - }, - Err(MissingSecond) => { - self.index = self.slice.len(); - Some((start, Err(Incomplete), 1)) - } - } - } - #[inline] - fn size_hint(&self) -> (usize,Option<usize>) { - let units = self.slice.len() - self.index; - // Cannot be exact, so KISS and don't bother rounding up. - // The slice is unlikely be full of surrogate pairs, so buffers - // allocated with the lower bound will have to be grown anyway. - (units/2, Some(units)) - } -} -impl<'a> Debug for Utf16CharDecoder<'a> { - fn fmt(&self, fmtr: &mut fmt::Formatter) -> fmt::Result { - write!(fmtr, "Utf16CharDecoder {{ units[{}..]: {:?} }}", self.index, self.as_slice()) - } -} |