Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

1 files changed, 494 insertions, 0 deletions

diff --git a/vendor/encode_unicode/src/decoding_iterators.rs b/vendor/encode_unicode/src/decoding_iterators.rs
new file mode 100644
index 0000000..4ef4125
--- /dev/null
+++ b/vendor/encode_unicode/src/decoding_iterators.rs
@@ -0,0 +1,494 @@
+/* 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())
+    }
+}