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Diffstat (limited to 'vendor/encode_unicode/src/traits.rs')
| -rw-r--r-- | vendor/encode_unicode/src/traits.rs | 1014 |
1 files changed, 0 insertions, 1014 deletions
diff --git a/vendor/encode_unicode/src/traits.rs b/vendor/encode_unicode/src/traits.rs deleted file mode 100644 index 3f36903..0000000 --- a/vendor/encode_unicode/src/traits.rs +++ /dev/null @@ -1,1014 +0,0 @@ -/* Copyright 2016 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. - */ - -#![allow(unused_unsafe)]// explicit unsafe{} blocks in unsafe functions are a good thing. - -use utf8_char::Utf8Char; -use utf16_char::Utf16Char; -use utf8_iterators::*; -use utf16_iterators::*; -use decoding_iterators::*; -use error::*; -extern crate core; -use self::core::{char, u32, mem}; -use self::core::ops::{Not, Index, RangeFull}; -use self::core::borrow::Borrow; -#[cfg(feature="ascii")] -extern crate ascii; -#[cfg(feature="ascii")] -use self::ascii::AsciiStr; - -// TODO better docs and tests - -/// Methods for working with `u8`s as UTF-8 bytes. -pub trait U8UtfExt { - /// How many more bytes will you need to complete this codepoint? - /// - /// # Errors - /// - /// An error is returned if the byte is not a valid start of an UTF-8 - /// codepoint: - /// - /// * `128..192`: ContinuationByte - /// * `248..`: TooLongSequence - /// - /// Values in 244..248 represent a too high codepoint, but do not cause an - /// error. - fn extra_utf8_bytes(self) -> Result<usize,InvalidUtf8FirstByte>; - - /// How many more bytes will you need to complete this codepoint? - /// - /// This function assumes that the byte is a valid UTF-8 start, and might - /// return any value otherwise. (but the function is pure and safe to call - /// with any value). - fn extra_utf8_bytes_unchecked(self) -> usize; -} - -impl U8UtfExt for u8 { - #[inline] - fn extra_utf8_bytes(self) -> Result<usize,InvalidUtf8FirstByte> { - use error::InvalidUtf8FirstByte::{ContinuationByte,TooLongSeqence}; - // the bit twiddling is explained in extra_utf8_bytes_unchecked() - if self < 128 { - return Ok(0); - } - match ((self as u32)<<25).not().leading_zeros() { - n @ 1...3 => Ok(n as usize), - 0 => Err(ContinuationByte), - _ => Err(TooLongSeqence), - } - } - #[inline] - fn extra_utf8_bytes_unchecked(self) -> usize { - // For fun I've optimized this function (for x86 instruction count): - // The most straightforward implementation, that lets the compiler do - // the optimizing: - //match self { - // 0b0000_0000...0b0111_1111 => 0, - // 0b1100_0010...0b1101_1111 => 1, - // 0b1110_0000...0b1110_1111 => 2, - // 0b1111_0000...0b1111_0100 => 3, - // _ => whatever() - //} - // Using `unsafe{self::core::hint::unreachable_unchecked()}` for the - // "don't care" case is a terrible idea: while having the function - // non-deterministically return whatever happens to be in a register - // MIGHT be acceptable, it permits the function to not `ret`urn at all, - // but let execution fall through to whatever comes after it in the - // binary! (in other words completely UB). - // Currently unreachable_unchecked() might trap too, - // which is certainly not what we want. - // I also think `unsafe{mem::unitialized()}` is much more likely to - // explicitly produce whatever happens to be in a register than tell - // the compiler it can ignore this branch but needs to produce a value. - // - // From the bit patterns we see that for non-ASCII values the result is - // (number of leading set bits) - 1 - // The standard library doesn't have a method for counting leading ones, - // but it has leading_zeros(), which can be used after inverting. - // This function can therefore be reduced to the one-liner - //`self.not().leading_zeros().saturating_sub(1) as usize`, which would - // be branchless for architectures with instructions for - // leading_zeros() and saturating_sub(). - - // Shortest version as long as ASCII-ness can be predicted: (especially - // if the BSR instruction which leading_zeros() uses is microcoded or - // doesn't exist) - // u8.leading_zeros() would cast to a bigger type internally, so that's - // free. compensating by shifting left by 24 before inverting lets the - // compiler know that the value passed to leading_zeros() is not zero, - // for which BSR's output is undefined and leading_zeros() normally has - // special case with a branch. - // Shifting one bit too many left acts as a saturating_sub(1). - if self<128 {0} else {((self as u32)<<25).not().leading_zeros() as usize} - - // Branchless but longer version: (9 instructions) - // It's tempting to try (self|0x80).not().leading_zeros().wrapping_sub(1), - // but that produces high lengths for ASCII values 0b01xx_xxxx. - // If we could somehow (branchlessy) clear that bit for ASCII values... - // We can by masking with the value shifted right with sign extension! - // (any nonzero number of bits in range works) - //let extended = self as i8 as i32; - //let ascii_cleared = (extended<<25) & (extended>>25); - //ascii_cleared.not().leading_zeros() as usize - - // cmov version: (7 instructions) - //(((self as u32)<<24).not().leading_zeros() as usize).saturating_sub(1) - } -} - - -/// Methods for working with `u16`s as UTF-16 units. -pub trait U16UtfExt { - /// Will you need an extra unit to complete this codepoint? - /// - /// Returns `Err` for trailing surrogates, `Ok(true)` for leading surrogates, - /// and `Ok(false)` for others. - fn utf16_needs_extra_unit(self) -> Result<bool,InvalidUtf16FirstUnit>; - - /// Does this `u16` need another `u16` to complete a codepoint? - /// Returns `(self & 0xfc00) == 0xd800` - /// - /// Is basically an unchecked variant of `utf16_needs_extra_unit()`. - fn is_utf16_leading_surrogate(self) -> bool; -} -impl U16UtfExt for u16 { - #[inline] - fn utf16_needs_extra_unit(self) -> Result<bool,InvalidUtf16FirstUnit> { - match self { - // https://en.wikipedia.org/wiki/UTF-16#U.2B10000_to_U.2B10FFFF - 0x00_00...0xd7_ff | 0xe0_00...0xff_ff => Ok(false), - 0xd8_00...0xdb_ff => Ok(true), - _ => Err(InvalidUtf16FirstUnit) - } - } - #[inline] - fn is_utf16_leading_surrogate(self) -> bool { - (self & 0xfc00) == 0xd800// Clear the ten content bytes of a surrogate, - // and see if it's a leading surrogate. - } -} - - - - -/// Extension trait for `char` that adds methods for converting to and from UTF-8 or UTF-16. -pub trait CharExt: Sized { - /// Get the UTF-8 representation of this codepoint. - /// - /// `Utf8Char` is to `[u8;4]` what `char` is to `u32`: - /// a restricted type that cannot be mutated internally. - fn to_utf8(self) -> Utf8Char; - - /// Get the UTF-16 representation of this codepoint. - /// - /// `Utf16Char` is to `[u16;2]` what `char` is to `u32`: - /// a restricted type that cannot be mutated internally. - fn to_utf16(self) -> Utf16Char; - - /// Iterate over or [read](https://doc.rust-lang.org/std/io/trait.Read.html) - /// the one to four bytes in the UTF-8 representation of this codepoint. - /// - /// An identical alternative to the unstable `char.encode_utf8()`. - /// That method somehow still exist on stable, so I have to use a different name. - fn iter_utf8_bytes(self) -> Utf8Iterator; - - /// Iterate over the one or two units in the UTF-16 representation of this codepoint. - /// - /// An identical alternative to the unstable `char.encode_utf16()`. - /// That method somehow still exist on stable, so I have to use a different name. - fn iter_utf16_units(self) -> Utf16Iterator; - - - /// Convert this char to an UTF-8 array, and also return how many bytes of - /// the array are used, - /// - /// The returned array is left-aligned with unused bytes set to zero. - fn to_utf8_array(self) -> ([u8; 4], usize); - - /// Convert this `char` to UTF-16. - /// - /// The second element is non-zero when a surrogate pair is required. - /// - /// # Examples - /// - /// ``` - /// use encode_unicode::CharExt; - /// - /// assert_eq!('@'.to_utf16_array(), ['@' as u16, 0]); - /// assert_eq!('睷'.to_utf16_array(), ['睷' as u16, 0]); - /// assert_eq!('\u{abcde}'.to_utf16_array(), [0xda6f, 0xdcde]); - /// ``` - fn to_utf16_array(self) -> [u16; 2]; - - /// Convert this `char` to UTF-16. - /// The second item is `Some` if a surrogate pair is required. - /// - /// # Examples - /// - /// ``` - /// use encode_unicode::CharExt; - /// - /// assert_eq!('@'.to_utf16_tuple(), ('@' as u16, None)); - /// assert_eq!('睷'.to_utf16_tuple(), ('睷' as u16, None)); - /// assert_eq!('\u{abcde}'.to_utf16_tuple(), (0xda6f, Some(0xdcde))); - /// ``` - fn to_utf16_tuple(self) -> (u16, Option<u16>); - - - - /// Create a `char` from the start of an UTF-8 slice, - /// and also return how many bytes were used. - /// - /// # Errors - /// - /// Returns an `Err` if the slice is empty, doesn't start with a valid - /// UTF-8 sequence or is too short for the sequence. - /// - /// # Examples - /// - /// ``` - /// use encode_unicode::CharExt; - /// use encode_unicode::error::InvalidUtf8Slice::*; - /// use encode_unicode::error::InvalidUtf8::*; - /// - /// assert_eq!(char::from_utf8_slice_start(&[b'A', b'B', b'C']), Ok(('A',1))); - /// assert_eq!(char::from_utf8_slice_start(&[0xdd, 0xbb]), Ok(('\u{77b}',2))); - /// - /// assert_eq!(char::from_utf8_slice_start(&[]), Err(TooShort(1))); - /// assert_eq!(char::from_utf8_slice_start(&[0xf0, 0x99]), Err(TooShort(4))); - /// assert_eq!(char::from_utf8_slice_start(&[0xee, b'F', 0x80]), Err(Utf8(NotAContinuationByte(1)))); - /// assert_eq!(char::from_utf8_slice_start(&[0xee, 0x99, 0x0f]), Err(Utf8(NotAContinuationByte(2)))); - /// ``` - fn from_utf8_slice_start(src: &[u8]) -> Result<(Self,usize),InvalidUtf8Slice>; - - /// Create a `char` from the start of an UTF-16 slice, - /// and also return how many units were used. - /// - /// If you want to continue after an error, continue with the next `u16` unit. - fn from_utf16_slice_start(src: &[u16]) -> Result<(Self,usize), InvalidUtf16Slice>; - - - /// Convert an UTF-8 sequence as returned from `.to_utf8_array()` into a `char` - /// - /// The codepoint must start at the first byte, and leftover bytes are ignored. - /// - /// # Errors - /// - /// Returns an `Err` if the array doesn't start with a valid UTF-8 sequence. - /// - /// # Examples - /// - /// ``` - /// use encode_unicode::CharExt; - /// use encode_unicode::error::InvalidUtf8Array::*; - /// use encode_unicode::error::InvalidUtf8::*; - /// use encode_unicode::error::InvalidCodepoint::*; - /// - /// assert_eq!(char::from_utf8_array([b'A', 0, 0, 0]), Ok('A')); - /// assert_eq!(char::from_utf8_array([0xf4, 0x8b, 0xbb, 0xbb]), Ok('\u{10befb}')); - /// assert_eq!(char::from_utf8_array([b'A', b'B', b'C', b'D']), Ok('A')); - /// assert_eq!(char::from_utf8_array([0, 0, 0xcc, 0xbb]), Ok('\0')); - /// - /// assert_eq!(char::from_utf8_array([0xef, b'F', 0x80, 0x80]), Err(Utf8(NotAContinuationByte(1)))); - /// assert_eq!(char::from_utf8_array([0xc1, 0x80, 0, 0]), Err(Utf8(OverLong))); - /// assert_eq!(char::from_utf8_array([0xf7, 0xaa, 0x99, 0x88]), Err(Codepoint(TooHigh))); - /// ``` - fn from_utf8_array(utf8: [u8; 4]) -> Result<Self,InvalidUtf8Array>; - - /// Convert a UTF-16 pair as returned from `.to_utf16_array()` into a `char`. - /// - /// The second element is ignored when not required. - /// - /// # Examples - /// - /// ``` - /// use encode_unicode::CharExt; - /// use encode_unicode::error::InvalidUtf16Array; - /// - /// assert_eq!(char::from_utf16_array(['x' as u16, 'y' as u16]), Ok('x')); - /// assert_eq!(char::from_utf16_array(['睷' as u16, 0]), Ok('睷')); - /// assert_eq!(char::from_utf16_array([0xda6f, 0xdcde]), Ok('\u{abcde}')); - /// assert_eq!(char::from_utf16_array([0xf111, 0xdbad]), Ok('\u{f111}')); - /// assert_eq!(char::from_utf16_array([0xdaaf, 0xdaaf]), Err(InvalidUtf16Array::SecondIsNotTrailingSurrogate)); - /// assert_eq!(char::from_utf16_array([0xdcac, 0x9000]), Err(InvalidUtf16Array::FirstIsTrailingSurrogate)); - /// ``` - fn from_utf16_array(utf16: [u16; 2]) -> Result<Self, InvalidUtf16Array>; - - /// Convert a UTF-16 pair as returned from `.to_utf16_tuple()` into a `char`. - fn from_utf16_tuple(utf16: (u16, Option<u16>)) -> Result<Self, InvalidUtf16Tuple>; - - - /// Convert an UTF-8 sequence into a char. - /// - /// The length of the slice is taken as length of the sequence; - /// it should be 1,2,3 or 4. - /// - /// # Safety - /// - /// The slice must contain exactly one, valid, UTF-8 sequence. - /// - /// Passing a slice that produces an invalid codepoint is always undefined - /// behavior; Later checks that the codepoint is valid can be removed - /// by the compiler. - /// - /// # Panics - /// - /// If the slice is empty - unsafe fn from_utf8_exact_slice_unchecked(src: &[u8]) -> Self; - - /// Convert a UTF-16 array as returned from `.to_utf16_array()` into a - /// `char`. - /// - /// This function is safe because it avoids creating invalid codepoints, - /// but the returned value might not be what one expectedd. - /// - /// # Examples - /// - /// ``` - /// use encode_unicode::CharExt; - /// - /// // starts with a trailing surrogate - converted as if it was a valid - /// // surrogate pair anyway. - /// assert_eq!(char::from_utf16_array_unchecked([0xdbad, 0xf19e]), '\u{fb59e}'); - /// // missing trailing surrogate - ditto - /// assert_eq!(char::from_utf16_array_unchecked([0xd802, 0]), '\u{10800}'); - /// ``` - fn from_utf16_array_unchecked(utf16: [u16;2]) -> Self; - - /// Convert a UTF-16 tuple as returned from `.to_utf16_tuple()` into a `char`. - unsafe fn from_utf16_tuple_unchecked(utf16: (u16, Option<u16>)) -> Self; - - - /// Produces more detailed errors than `char::from_u32()` - /// - /// # Errors - /// - /// This function will return an error if - /// - /// * the value is greater than 0x10ffff - /// * the value is between 0xd800 and 0xdfff (inclusive) - /// - /// # Examples - /// - /// ``` - /// use encode_unicode::CharExt; - /// use encode_unicode::error::InvalidCodepoint; - /// - /// assert_eq!(char::from_u32_detailed(0x41), Ok('A')); - /// assert_eq!(char::from_u32_detailed(0x40_00_00), Err(InvalidCodepoint::TooHigh)); - /// assert_eq!(char::from_u32_detailed(0xd951), Err(InvalidCodepoint::Utf16Reserved)); - /// assert_eq!(char::from_u32_detailed(0xdddd), Err(InvalidCodepoint::Utf16Reserved)); - /// assert_eq!(char::from_u32_detailed(0xdd), Ok('Ý')); - /// assert_eq!(char::from_u32_detailed(0x1f331), Ok('🌱')); - /// ``` - fn from_u32_detailed(c: u32) -> Result<Self,InvalidCodepoint>; -} - - - -impl CharExt for char { - ///////// - //UTF-8// - ///////// - - fn to_utf8(self) -> Utf8Char { - self.into() - } - fn iter_utf8_bytes(self) -> Utf8Iterator { - self.to_utf8().into_iter() - } - - fn to_utf8_array(self) -> ([u8; 4], usize) { - let len = self.len_utf8(); - let mut c = self as u32; - if len == 1 {// ASCII, the common case - ([c as u8, 0, 0, 0], 1) - } else { - let mut parts = 0;// convert to 6-bit bytes - parts |= c & 0x3f; c>>=6; - parts<<=8; parts |= c & 0x3f; c>>=6; - parts<<=8; parts |= c & 0x3f; c>>=6; - parts<<=8; parts |= c & 0x3f; - parts |= 0x80_80_80_80;// set the most significant bit - parts >>= 8*(4-len);// right-align bytes - // Now, unused bytes are zero, (which matters for Utf8Char.eq()) - // and the rest are 0b10xx_xxxx - - // set header on first byte - parts |= (0xff_00u32 >> len) & 0xff;// store length - parts &= Not::not(1u32 << 7-len);// clear the next bit after it - - let bytes: [u8; 4] = unsafe{ mem::transmute(u32::from_le(parts)) }; - (bytes, len) - } - } - - - fn from_utf8_slice_start(src: &[u8]) -> Result<(Self,usize),InvalidUtf8Slice> { - use errors::InvalidUtf8::*; - use errors::InvalidUtf8Slice::*; - let first = match src.first() { - Some(first) => *first, - None => return Err(TooShort(1)), - }; - let bytes = match first.extra_utf8_bytes() { - Err(e) => return Err(Utf8(FirstByte(e))), - Ok(0) => return Ok((first as char, 1)), - Ok(extra) if extra >= src.len() - => return Err(TooShort(extra+1)), - Ok(extra) => &src[..extra+1], - }; - if let Some(i) = bytes.iter().skip(1).position(|&b| (b >> 6) != 0b10 ) { - Err(Utf8(NotAContinuationByte(i+1))) - } else if overlong(bytes[0], bytes[1]) { - Err(Utf8(OverLong)) - } else { - match char::from_u32_detailed(merge_nonascii_unchecked_utf8(bytes)) { - Ok(c) => Ok((c, bytes.len())), - Err(e) => Err(Codepoint(e)), - } - } - } - - fn from_utf8_array(utf8: [u8; 4]) -> Result<Self,InvalidUtf8Array> { - use errors::InvalidUtf8::*; - use errors::InvalidUtf8Array::*; - let src = match utf8[0].extra_utf8_bytes() { - Err(error) => return Err(Utf8(FirstByte(error))), - Ok(0) => return Ok(utf8[0] as char), - Ok(extra) => &utf8[..extra+1], - }; - if let Some(i) = src[1..].iter().position(|&b| (b >> 6) != 0b10 ) { - Err(Utf8(NotAContinuationByte(i+1))) - } else if overlong(utf8[0], utf8[1]) { - Err(Utf8(OverLong)) - } else { - char::from_u32_detailed(merge_nonascii_unchecked_utf8(src)) - .map_err(|e| Codepoint(e) ) - } - } - - unsafe fn from_utf8_exact_slice_unchecked(src: &[u8]) -> Self { - if src.len() == 1 { - src[0] as char - } else { - char::from_u32_unchecked(merge_nonascii_unchecked_utf8(src)) - } - } - - - - ////////// - //UTF-16// - ////////// - - fn to_utf16(self) -> Utf16Char { - Utf16Char::from(self) - } - fn iter_utf16_units(self) -> Utf16Iterator { - self.to_utf16().into_iter() - } - - fn to_utf16_array(self) -> [u16;2] { - let (first, second) = self.to_utf16_tuple(); - [first, second.unwrap_or(0)] - } - fn to_utf16_tuple(self) -> (u16, Option<u16>) { - if self <= '\u{ffff}' {// single - (self as u16, None) - } else {// double - let c = self as u32 - 0x_01_00_00; - let high = 0x_d8_00 + (c >> 10); - let low = 0x_dc_00 + (c & 0x_03_ff); - (high as u16, Some(low as u16)) - } - } - - - fn from_utf16_slice_start(src: &[u16]) -> Result<(Self,usize), InvalidUtf16Slice> { - use errors::InvalidUtf16Slice::*; - unsafe {match (src.get(0), src.get(1)) { - (Some(&u @ 0x00_00...0xd7_ff), _) | - (Some(&u @ 0xe0_00...0xff_ff), _) - => Ok((char::from_u32_unchecked(u as u32), 1)), - (Some(&0xdc_00...0xdf_ff), _) => Err(FirstLowSurrogate), - (None, _) => Err(EmptySlice), - (Some(&f @ 0xd8_00...0xdb_ff), Some(&s @ 0xdc_00...0xdf_ff)) - => Ok((char::from_utf16_tuple_unchecked((f, Some(s))), 2)), - (Some(&0xd8_00...0xdb_ff), Some(_)) => Err(SecondNotLowSurrogate), - (Some(&0xd8_00...0xdb_ff), None) => Err(MissingSecond), - (Some(_), _) => unreachable!() - }} - } - - fn from_utf16_array(utf16: [u16;2]) -> Result<Self, InvalidUtf16Array> { - use errors::InvalidUtf16Array::*; - if let Some(c) = char::from_u32(utf16[0] as u32) { - Ok(c) // single - } else if utf16[0] < 0xdc_00 && utf16[1] & 0xfc_00 == 0xdc_00 { - // correct surrogate pair - Ok(combine_surrogates(utf16[0], utf16[1])) - } else if utf16[0] < 0xdc_00 { - Err(SecondIsNotTrailingSurrogate) - } else { - Err(FirstIsTrailingSurrogate) - } - } - fn from_utf16_tuple(utf16: (u16, Option<u16>)) -> Result<Self, InvalidUtf16Tuple> { - use errors::InvalidUtf16Tuple::*; - unsafe{ match utf16 { - (0x00_00...0xd7_ff, None) | // single - (0xe0_00...0xff_ff, None) | // single - (0xd8_00...0xdb_ff, Some(0xdc_00...0xdf_ff)) // correct surrogate - => Ok(char::from_utf16_tuple_unchecked(utf16)), - (0xd8_00...0xdb_ff, Some(_)) => Err(InvalidSecond), - (0xd8_00...0xdb_ff, None ) => Err(MissingSecond), - (0xdc_00...0xdf_ff, _ ) => Err(FirstIsTrailingSurrogate), - ( _ , Some(_)) => Err(SuperfluousSecond), - ( _ , None ) => unreachable!() - }} - } - - fn from_utf16_array_unchecked(utf16: [u16;2]) -> Self { - // treat any array with a surrogate value in [0] as a surrogate because - // combine_surrogates() is safe. - // `(utf16[0] & 0xf800) == 0xd80` might not be quite as fast as - // `utf16[1] != 0`, but avoiding the potential for UB is worth it - // since the conversion isn't zero-cost in either case. - char::from_u32(utf16[0] as u32) - .unwrap_or_else(|| combine_surrogates(utf16[0], utf16[1]) ) - } - unsafe fn from_utf16_tuple_unchecked(utf16: (u16, Option<u16>)) -> Self { - match utf16.1 { - Some(second) => combine_surrogates(utf16.0, second), - None => char::from_u32_unchecked(utf16.0 as u32) - } - } - - - fn from_u32_detailed(c: u32) -> Result<Self,InvalidCodepoint> { - match char::from_u32(c) { - Some(c) => Ok(c), - None if c > 0x10_ff_ff => Err(InvalidCodepoint::TooHigh), - None => Err(InvalidCodepoint::Utf16Reserved), - } - } -} - -// Adapted from https://www.cl.cam.ac.uk/~mgk25/ucs/utf8_check.c -fn overlong(first: u8, second: u8) -> bool { - if first < 0x80 { - false - } else if (first & 0xe0) == 0xc0 { - (first & 0xfe) == 0xc0 - } else if (first & 0xf0) == 0xe0 { - first == 0xe0 && (second & 0xe0) == 0x80 - } else { - first == 0xf0 && (second & 0xf0) == 0x80 - } -} - -/// Decodes the codepoint represented by a multi-byte UTF-8 sequence. -/// -/// Does not check that the codepoint is valid, -/// and returns `u32` because casting invalid codepoints to `char` is insta UB. -fn merge_nonascii_unchecked_utf8(src: &[u8]) -> u32 { - let mut c = src[0] as u32 & (0x7f >> src.len()); - for b in &src[1..] { - c = (c << 6) | (b & 0b0011_1111) as u32; - } - c -} - -/// Create a `char` from a leading and a trailing surrogate. -/// -/// This function is safe because it ignores the six most significant bits of -/// each arguments and always produces a codepoint in 0x01_00_00..=0x10_ff_ff. -fn combine_surrogates(first: u16, second: u16) -> char { - unsafe { - let high = (first & 0x_03_ff) as u32; - let low = (second & 0x_03_ff) as u32; - let c = ((high << 10) | low) + 0x_01_00_00; // no, the constant can't be or'd in - char::from_u32_unchecked(c) - } -} - - - -/// Adds `.utf8chars()` and `.utf16chars()` iterator constructors to `&str`. -pub trait StrExt: AsRef<str> { - /// Equivalent to `.chars()` but produces `Utf8Char`s. - fn utf8chars(&self) -> Utf8Chars; - /// Equivalent to `.chars()` but produces `Utf16Char`s. - fn utf16chars(&self) -> Utf16Chars; - /// Equivalent to `.char_indices()` but produces `Utf8Char`s. - fn utf8char_indices(&self) -> Utf8CharIndices; - /// Equivalent to `.char_indices()` but produces `Utf16Char`s. - fn utf16char_indices(&self) -> Utf16CharIndices; -} - -impl StrExt for str { - fn utf8chars(&self) -> Utf8Chars { - Utf8Chars::from(self) - } - fn utf16chars(&self) -> Utf16Chars { - Utf16Chars::from(self) - } - fn utf8char_indices(&self) -> Utf8CharIndices { - Utf8CharIndices::from(self) - } - fn utf16char_indices(&self) -> Utf16CharIndices { - Utf16CharIndices::from(self) - } -} - -#[cfg(feature="ascii")] -impl StrExt for AsciiStr { - fn utf8chars(&self) -> Utf8Chars { - Utf8Chars::from(self.as_str()) - } - fn utf16chars(&self) -> Utf16Chars { - Utf16Chars::from(self.as_str()) - } - fn utf8char_indices(&self) -> Utf8CharIndices { - Utf8CharIndices::from(self.as_str()) - } - fn utf16char_indices(&self) -> Utf16CharIndices { - Utf16CharIndices::from(self.as_str()) - } -} - - - -/// Iterator methods that convert between `u8`s and `Utf8Char` or `u16`s and `Utf16Char` -/// -/// All the iterator adapters also accept iterators that produce references of -/// the type they convert from. -pub trait IterExt: Iterator+Sized { - /// Converts an iterator of `Utf8Char`s or `&Utf8Char`s to an iterator of - /// `u8`s. - /// - /// Has the same effect as `.flat_map()` or `.flatten()`, but the returned - /// iterator is ~40% faster. - /// - /// The iterator also implements `Read` - /// (when the `std` feature isn't disabled). - /// Reading will never produce an error, and calls to `.read()` and `.next()` - /// can be mixed. - /// - /// The exact number of bytes cannot be known in advance, but `size_hint()` - /// gives the possible range. - /// (min: all remaining characters are ASCII, max: all require four bytes) - /// - /// # Examples - /// - /// From iterator of values: - /// - /// ``` - /// use encode_unicode::{IterExt, StrExt}; - /// - /// let iterator = "foo".utf8chars(); - /// let mut bytes = [0; 4]; - /// for (u,dst) in iterator.to_bytes().zip(&mut bytes) {*dst=u;} - /// assert_eq!(&bytes, b"foo\0"); - /// ``` - /// - /// From iterator of references: - /// - #[cfg_attr(feature="std", doc=" ```")] - #[cfg_attr(not(feature="std"), doc=" ```no_compile")] - /// use encode_unicode::{IterExt, StrExt, Utf8Char}; - /// - /// let chars: Vec<Utf8Char> = "💣 bomb 💣".utf8chars().collect(); - /// let bytes: Vec<u8> = chars.iter().to_bytes().collect(); - /// let flat_map: Vec<u8> = chars.iter().flat_map(|u8c| *u8c ).collect(); - /// assert_eq!(bytes, flat_map); - /// ``` - /// - /// `Read`ing from it: - /// - #[cfg_attr(feature="std", doc=" ```")] - #[cfg_attr(not(feature="std"), doc=" ```no_compile")] - /// use encode_unicode::{IterExt, StrExt}; - /// use std::io::Read; - /// - /// let s = "Ååh‽"; - /// assert_eq!(s.len(), 8); - /// let mut buf = [b'E'; 9]; - /// let mut reader = s.utf8chars().to_bytes(); - /// assert_eq!(reader.read(&mut buf[..]).unwrap(), 8); - /// assert_eq!(reader.read(&mut buf[..]).unwrap(), 0); - /// assert_eq!(&buf[..8], s.as_bytes()); - /// assert_eq!(buf[8], b'E'); - /// ``` - fn to_bytes(self) -> Utf8CharSplitter<Self::Item,Self> where Self::Item: Borrow<Utf8Char>; - - /// Converts an iterator of `Utf16Char` (or `&Utf16Char`) to an iterator of - /// `u16`s. - /// - /// Has the same effect as `.flat_map()` or `.flatten()`, but the returned - /// iterator is about twice as fast. - /// - /// The exact number of units cannot be known in advance, but `size_hint()` - /// gives the possible range. - /// - /// # Examples - /// - /// From iterator of values: - /// - /// ``` - /// use encode_unicode::{IterExt, StrExt}; - /// - /// let iterator = "foo".utf16chars(); - /// let mut units = [0; 4]; - /// for (u,dst) in iterator.to_units().zip(&mut units) {*dst=u;} - /// - /// assert_eq!(units, ['f' as u16, 'o' as u16, 'o' as u16, 0]); - /// ``` - /// - /// From iterator of references: - /// - #[cfg_attr(feature="std", doc=" ```")] - #[cfg_attr(not(feature="std"), doc=" ```no_compile")] - /// use encode_unicode::{IterExt, StrExt, Utf16Char}; - /// - /// // (💣 takes two units) - /// let chars: Vec<Utf16Char> = "💣 bomb 💣".utf16chars().collect(); - /// let units: Vec<u16> = chars.iter().to_units().collect(); - /// let flat_map: Vec<u16> = chars.iter().flat_map(|u16c| *u16c ).collect(); - /// - /// assert_eq!(units, flat_map); - /// ``` - fn to_units(self) -> Utf16CharSplitter<Self::Item,Self> where Self::Item: Borrow<Utf16Char>; - - /// Decodes bytes as UTF-8 and groups them into `Utf8Char`s - /// - /// When errors (invalid values or sequences) are encountered, - /// it continues with the byte right after the start of the error sequence. - /// This is neither the most intelligent choiche (sometimes it is guaranteed to - /// produce another error), nor the easiest to implement, but I believe it to - /// be the most predictable. - /// It also means that ASCII characters are never hidden by errors. - /// - /// # Examples - /// - /// Replace all errors with u+FFFD REPLACEMENT_CHARACTER: - /// ``` - /// use encode_unicode::{Utf8Char, IterExt}; - /// - /// let mut buf = [b'\0'; 255]; - /// let len = b"foo\xCFbar".iter() - /// .to_utf8chars() - /// .flat_map(|r| r.unwrap_or(Utf8Char::from('\u{FFFD}')).into_iter() ) - /// .zip(&mut buf[..]) - /// .map(|(byte, dst)| *dst = byte ) - /// .count(); - /// - /// assert_eq!(&buf[..len], "foo\u{FFFD}bar".as_bytes()); - /// ``` - /// - /// Collect everything up until the first error into a string: - #[cfg_attr(feature="std", doc=" ```")] - #[cfg_attr(not(feature="std"), doc=" ```no_compile")] - /// use encode_unicode::iterator::Utf8CharMerger; - /// let mut good = String::new(); - /// for r in Utf8CharMerger::from(b"foo\xcc\xbbbar\xcc\xddbaz") { - /// if let Ok(uc) = r { - /// good.push_str(uc.as_str()); - /// } else { - /// break; - /// } - /// } - /// assert_eq!(good, "foo̻bar"); - /// ``` - /// - /// Abort decoding on error: - #[cfg_attr(feature="std", doc=" ```")] - #[cfg_attr(not(feature="std"), doc=" ```no_compile")] - /// use encode_unicode::{IterExt, Utf8Char}; - /// use encode_unicode::error::{InvalidUtf8Slice, InvalidUtf8}; - /// - /// let result = b"ab\0\xe0\xbc\xa9 \xf3\x80\x77".iter() - /// .to_utf8chars() - /// .collect::<Result<String,InvalidUtf8Slice>>(); - /// - /// assert_eq!(result, Err(InvalidUtf8Slice::Utf8(InvalidUtf8::NotAContinuationByte(2)))); - /// ``` - fn to_utf8chars(self) -> Utf8CharMerger<Self::Item,Self> where Self::Item: Borrow<u8>; - - /// Decodes bytes as UTF-16 and groups them into `Utf16Char`s - /// - /// When errors (unmatched leading surrogates or unexpected trailing surrogates) - /// are encountered, an error is produced for every unit. - /// - /// # Examples - /// - /// Replace errors with '�': - #[cfg_attr(feature="std", doc=" ```")] - #[cfg_attr(not(feature="std"), doc=" ```no_compile")] - /// use encode_unicode::{IterExt, Utf16Char}; - /// - /// let slice = &['a' as u16, 0xdf00, 0xd83c, 0xdca0][..]; - /// let string = slice.iter() - /// .to_utf16chars() - /// .map(|r| r.unwrap_or(Utf16Char::from('\u{fffd}')) ) // REPLACEMENT_CHARACTER - /// .collect::<String>(); - /// - /// assert_eq!(string, "a�🂠"); - /// ``` - /// - /// ``` - /// use encode_unicode::{IterExt, Utf16Char}; - /// use encode_unicode::error::Utf16PairError::*; - /// - /// let slice = [0xdcba, 0xdeff, 0xd8be, 0xdeee, 'Y' as u16, 0xdab1, 0xdab1]; - /// let mut iter = slice.iter().to_utf16chars(); - /// assert_eq!(iter.size_hint(), (3, Some(7))); - /// assert_eq!(iter.next(), Some(Err(UnexpectedTrailingSurrogate))); - /// assert_eq!(iter.next(), Some(Err(UnexpectedTrailingSurrogate))); - /// assert_eq!(iter.next(), Some(Ok(Utf16Char::from('\u{3faee}')))); - /// assert_eq!(iter.next(), Some(Ok(Utf16Char::from('Y')))); - /// assert_eq!(iter.next(), Some(Err(UnmatchedLeadingSurrogate))); - /// assert_eq!(iter.next(), Some(Err(Incomplete))); - /// assert_eq!(iter.into_remaining_units().next(), None); - /// ``` - /// - /// Search for a codepoint and return the codepoint index of the first match: - /// ``` - /// use encode_unicode::{IterExt, Utf16Char}; - /// - /// let position = [0xd875, 0xdd4f, '≈' as u16, '2' as u16].iter() - /// .to_utf16chars() - /// .position(|r| r == Ok(Utf16Char::from('≈')) ); - /// - /// assert_eq!(position, Some(1)); - /// ``` - fn to_utf16chars(self) -> Utf16CharMerger<Self::Item,Self> where Self::Item: Borrow<u16>; -} - -impl<I:Iterator> IterExt for I { - fn to_bytes(self) -> Utf8CharSplitter<Self::Item,Self> where Self::Item: Borrow<Utf8Char> { - iter_bytes(self) - } - fn to_units(self) -> Utf16CharSplitter<Self::Item,Self> where Self::Item: Borrow<Utf16Char> { - iter_units(self) - } - fn to_utf8chars(self) -> Utf8CharMerger<Self::Item,Self> where Self::Item: Borrow<u8> { - Utf8CharMerger::from(self) - } - fn to_utf16chars(self) -> Utf16CharMerger<Self::Item,Self> where Self::Item: Borrow<u16> { - Utf16CharMerger::from(self) - } -} - - -/// Methods for iterating over `u8` and `u16` slices as UTF-8 or UTF-16 characters. -/// -/// The iterators are slightly faster than the similar methods in [`IterExt`](trait.IterExt.html) -/// because they con "push back" items for free after errors and don't need a -/// separate buffer that must be checked on every call to `.next()`. -pub trait SliceExt: Index<RangeFull> { - /// Decode `u8` slices as UTF-8 and iterate over the codepoints as `Utf8Char`s, - /// - /// # Examples - /// - /// Get the index and error type of the first error: - #[cfg_attr(feature="std", doc=" ```")] - #[cfg_attr(not(feature="std"), doc=" ```no_compile")] - /// use encode_unicode::{SliceExt, Utf8Char}; - /// use encode_unicode::error::InvalidUtf8Slice; - /// - /// let slice = b"ab\0\xe0\xbc\xa9 \xf3\x80\x77"; - /// let result = slice.utf8char_indices() - /// .map(|(offset,r,length)| r.map_err(|e| (offset,e,length) ) ) - /// .collect::<Result<String,(usize,InvalidUtf8Slice,usize)>>(); - /// - /// assert_eq!(result, Err((7, InvalidUtf8Slice::TooShort(4), 1))); - /// ``` - /// - /// ``` - /// use encode_unicode::{SliceExt, Utf8Char}; - /// use std::error::Error; - /// - /// let slice = b"\xf0\xbf\xbf\xbfXY\xdd\xbb\xe1\x80\x99quux123"; - /// let mut fixed_size = [Utf8Char::default(); 8]; - /// for (cp_i, (byte_index, r, _)) in slice.utf8char_indices().enumerate().take(8) { - /// match r { - /// Ok(u8c) => fixed_size[cp_i] = u8c, - /// Err(e) => panic!("Invalid codepoint at index {} ({})", cp_i, e.description()), - /// } - /// } - /// let chars = ['\u{3ffff}', 'X', 'Y', '\u{77b}', '\u{1019}', 'q', 'u', 'u']; - /// assert_eq!(fixed_size, chars); - /// ``` - /// - #[cfg_attr(feature="std", doc=" ```")] - #[cfg_attr(not(feature="std"), doc=" ```no_compile")] - /// use encode_unicode::{SliceExt, Utf8Char}; - /// use encode_unicode::error::InvalidUtf8Slice::*; - /// use encode_unicode::error::{InvalidUtf8, InvalidUtf8FirstByte, InvalidCodepoint}; - /// - /// let bytes = b"\xfa-\xf4\x8f\xee\xa1\x8f-\xed\xa9\x87\xf0\xcc\xbb"; - /// let mut errors = Vec::new(); - /// let mut lengths = Vec::new(); - /// let mut string = String::new(); - /// for (offset,result,length) in bytes.utf8char_indices() { - /// lengths.push((offset,length)); - /// let c = result.unwrap_or_else(|error| { - /// errors.push((offset,error)); - /// Utf8Char::from('\u{fffd}') // replacement character - /// }); - /// string.push_str(c.as_str()); - /// } - /// - /// assert_eq!(string, "�-��\u{e84f}-����\u{33b}"); - /// assert_eq!(lengths, [(0,1), (1,1), (2,1), (3,1), (4,3), (7,1), - /// (8,1), (9,1), (10,1), (11,1), (12,2)]); - /// assert_eq!(errors, [ - /// ( 0, Utf8(InvalidUtf8::FirstByte(InvalidUtf8FirstByte::TooLongSeqence))), - /// ( 2, Utf8(InvalidUtf8::NotAContinuationByte(2))), - /// ( 3, Utf8(InvalidUtf8::FirstByte(InvalidUtf8FirstByte::ContinuationByte))), - /// ( 8, Codepoint(InvalidCodepoint::Utf16Reserved)), - /// ( 9, Utf8(InvalidUtf8::FirstByte(InvalidUtf8FirstByte::ContinuationByte))), - /// (10, Utf8(InvalidUtf8::FirstByte(InvalidUtf8FirstByte::ContinuationByte))), - /// (11, TooShort(4)), // (but it was not the last element returned!) - /// ]); - /// ``` - fn utf8char_indices(&self) -> Utf8CharDecoder where Self::Output: Borrow<[u8]>; - - - /// Decode `u16` slices as UTF-16 and iterate over the codepoints as `Utf16Char`s, - /// - /// The iterator produces `(usize,Result<Utf16Char,Utf16Error>,usize)`, - /// and the slice is validated as you go. - /// - /// The first `usize` contains the offset from the start of the slice and - /// the last `usize` contains the length of the codepoint or error. - /// The length is either 1 or 2, and always 1 for errors. - /// - /// # Examples - /// - #[cfg_attr(feature="std", doc=" ```")] - #[cfg_attr(not(feature="std"), doc=" ```no_compile")] - /// use encode_unicode::{SliceExt, Utf8Char}; - /// - /// let slice = &['a' as u16, 0xdf00, 0xd83c, 0xdca0][..]; - /// let mut errors = Vec::new(); - /// let string = slice.utf16char_indices().map(|(offset,r,_)| match r { - /// Ok(u16c) => Utf8Char::from(u16c), - /// Err(_) => { - /// errors.push(offset); - /// Utf8Char::from('\u{fffd}') // REPLACEMENT_CHARACTER - /// } - /// }).collect::<String>(); - /// - /// assert_eq!(string, "a�🂠"); - /// assert_eq!(errors, [1]); - /// ``` - /// - /// Search for a codepoint and return its unit and codepoint index. - /// ``` - /// use encode_unicode::{SliceExt, Utf16Char}; - /// - /// let slice = [0xd875,/*'𝕏'*/ 0xdd4f, '≈' as u16, '2' as u16]; - /// let position = slice.utf16char_indices() - /// .enumerate() - /// .find(|&(_,(_,r,_))| r == Ok(Utf16Char::from('≈')) ) - /// .map(|(codepoint, (offset, _, _))| (codepoint, offset) ); - /// - /// assert_eq!(position, Some((1,2))); - /// ``` - /// - /// Error types: - /// ``` - /// use encode_unicode::{SliceExt, Utf16Char}; - /// use encode_unicode::error::Utf16PairError::*; - /// - /// let slice = [0xdcba, 0xdeff, 0xd8be, 0xdeee, 'λ' as u16, 0xdab1, 0xdab1]; - /// let mut iter = slice.utf16char_indices(); - /// assert_eq!(iter.next(), Some((0, Err(UnexpectedTrailingSurrogate), 1))); - /// assert_eq!(iter.next(), Some((1, Err(UnexpectedTrailingSurrogate), 1))); - /// assert_eq!(iter.next(), Some((2, Ok(Utf16Char::from('\u{3faee}')), 2))); - /// assert_eq!(iter.next(), Some((4, Ok(Utf16Char::from('λ')), 1))); - /// assert_eq!(iter.next(), Some((5, Err(UnmatchedLeadingSurrogate), 1))); - /// assert_eq!(iter.next(), Some((6, Err(Incomplete), 1))); - /// assert_eq!(iter.next(), None); - /// assert_eq!(iter.as_slice(), []) - /// ``` - fn utf16char_indices(&self) -> Utf16CharDecoder where Self::Output: Borrow<[u16]>; -} - -impl<S: ?Sized+Index<RangeFull>> SliceExt for S { - fn utf8char_indices(&self) -> Utf8CharDecoder where Self::Output: Borrow<[u8]> { - Utf8CharDecoder::from(self[..].borrow()) - } - fn utf16char_indices(&self) -> Utf16CharDecoder where Self::Output: Borrow<[u16]> { - Utf16CharDecoder::from(self[..].borrow()) - } -} |