838ddbf908
unlike the other Parse*Error types, ParseCharError didn't have these implemented for whatever reason
909 lines
29 KiB
Rust
909 lines
29 KiB
Rust
// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
|
|
// file at the top-level directory of this distribution and at
|
|
// http://rust-lang.org/COPYRIGHT.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
|
|
// http://www.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.
|
|
|
|
//! Character manipulation.
|
|
//!
|
|
//! For more details, see ::std_unicode::char (a.k.a. std::char)
|
|
|
|
#![allow(non_snake_case)]
|
|
#![stable(feature = "core_char", since = "1.2.0")]
|
|
|
|
use char_private::is_printable;
|
|
use convert::TryFrom;
|
|
use fmt::{self, Write};
|
|
use slice;
|
|
use str::{from_utf8_unchecked_mut, FromStr};
|
|
use iter::FusedIterator;
|
|
use mem::transmute;
|
|
|
|
// UTF-8 ranges and tags for encoding characters
|
|
const TAG_CONT: u8 = 0b1000_0000;
|
|
const TAG_TWO_B: u8 = 0b1100_0000;
|
|
const TAG_THREE_B: u8 = 0b1110_0000;
|
|
const TAG_FOUR_B: u8 = 0b1111_0000;
|
|
const MAX_ONE_B: u32 = 0x80;
|
|
const MAX_TWO_B: u32 = 0x800;
|
|
const MAX_THREE_B: u32 = 0x10000;
|
|
|
|
/*
|
|
Lu Uppercase_Letter an uppercase letter
|
|
Ll Lowercase_Letter a lowercase letter
|
|
Lt Titlecase_Letter a digraphic character, with first part uppercase
|
|
Lm Modifier_Letter a modifier letter
|
|
Lo Other_Letter other letters, including syllables and ideographs
|
|
Mn Nonspacing_Mark a nonspacing combining mark (zero advance width)
|
|
Mc Spacing_Mark a spacing combining mark (positive advance width)
|
|
Me Enclosing_Mark an enclosing combining mark
|
|
Nd Decimal_Number a decimal digit
|
|
Nl Letter_Number a letterlike numeric character
|
|
No Other_Number a numeric character of other type
|
|
Pc Connector_Punctuation a connecting punctuation mark, like a tie
|
|
Pd Dash_Punctuation a dash or hyphen punctuation mark
|
|
Ps Open_Punctuation an opening punctuation mark (of a pair)
|
|
Pe Close_Punctuation a closing punctuation mark (of a pair)
|
|
Pi Initial_Punctuation an initial quotation mark
|
|
Pf Final_Punctuation a final quotation mark
|
|
Po Other_Punctuation a punctuation mark of other type
|
|
Sm Math_Symbol a symbol of primarily mathematical use
|
|
Sc Currency_Symbol a currency sign
|
|
Sk Modifier_Symbol a non-letterlike modifier symbol
|
|
So Other_Symbol a symbol of other type
|
|
Zs Space_Separator a space character (of various non-zero widths)
|
|
Zl Line_Separator U+2028 LINE SEPARATOR only
|
|
Zp Paragraph_Separator U+2029 PARAGRAPH SEPARATOR only
|
|
Cc Control a C0 or C1 control code
|
|
Cf Format a format control character
|
|
Cs Surrogate a surrogate code point
|
|
Co Private_Use a private-use character
|
|
Cn Unassigned a reserved unassigned code point or a noncharacter
|
|
*/
|
|
|
|
/// The highest valid code point a `char` can have.
|
|
///
|
|
/// A [`char`] is a [Unicode Scalar Value], which means that it is a [Code
|
|
/// Point], but only ones within a certain range. `MAX` is the highest valid
|
|
/// code point that's a valid [Unicode Scalar Value].
|
|
///
|
|
/// [`char`]: ../../std/primitive.char.html
|
|
/// [Unicode Scalar Value]: http://www.unicode.org/glossary/#unicode_scalar_value
|
|
/// [Code Point]: http://www.unicode.org/glossary/#code_point
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub const MAX: char = '\u{10ffff}';
|
|
|
|
/// Converts a `u32` to a `char`.
|
|
///
|
|
/// Note that all [`char`]s are valid [`u32`]s, and can be casted to one with
|
|
/// [`as`]:
|
|
///
|
|
/// ```
|
|
/// let c = '💯';
|
|
/// let i = c as u32;
|
|
///
|
|
/// assert_eq!(128175, i);
|
|
/// ```
|
|
///
|
|
/// However, the reverse is not true: not all valid [`u32`]s are valid
|
|
/// [`char`]s. `from_u32()` will return `None` if the input is not a valid value
|
|
/// for a [`char`].
|
|
///
|
|
/// [`char`]: ../../std/primitive.char.html
|
|
/// [`u32`]: ../../std/primitive.u32.html
|
|
/// [`as`]: ../../book/first-edition/casting-between-types.html#as
|
|
///
|
|
/// For an unsafe version of this function which ignores these checks, see
|
|
/// [`from_u32_unchecked`].
|
|
///
|
|
/// [`from_u32_unchecked`]: fn.from_u32_unchecked.html
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// Basic usage:
|
|
///
|
|
/// ```
|
|
/// use std::char;
|
|
///
|
|
/// let c = char::from_u32(0x2764);
|
|
///
|
|
/// assert_eq!(Some('❤'), c);
|
|
/// ```
|
|
///
|
|
/// Returning `None` when the input is not a valid [`char`]:
|
|
///
|
|
/// ```
|
|
/// use std::char;
|
|
///
|
|
/// let c = char::from_u32(0x110000);
|
|
///
|
|
/// assert_eq!(None, c);
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn from_u32(i: u32) -> Option<char> {
|
|
char::try_from(i).ok()
|
|
}
|
|
|
|
/// Converts a `u32` to a `char`, ignoring validity.
|
|
///
|
|
/// Note that all [`char`]s are valid [`u32`]s, and can be casted to one with
|
|
/// [`as`]:
|
|
///
|
|
/// ```
|
|
/// let c = '💯';
|
|
/// let i = c as u32;
|
|
///
|
|
/// assert_eq!(128175, i);
|
|
/// ```
|
|
///
|
|
/// However, the reverse is not true: not all valid [`u32`]s are valid
|
|
/// [`char`]s. `from_u32_unchecked()` will ignore this, and blindly cast to
|
|
/// [`char`], possibly creating an invalid one.
|
|
///
|
|
/// [`char`]: ../../std/primitive.char.html
|
|
/// [`u32`]: ../../std/primitive.u32.html
|
|
/// [`as`]: ../../book/first-edition/casting-between-types.html#as
|
|
///
|
|
/// # Safety
|
|
///
|
|
/// This function is unsafe, as it may construct invalid `char` values.
|
|
///
|
|
/// For a safe version of this function, see the [`from_u32`] function.
|
|
///
|
|
/// [`from_u32`]: fn.from_u32.html
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// Basic usage:
|
|
///
|
|
/// ```
|
|
/// use std::char;
|
|
///
|
|
/// let c = unsafe { char::from_u32_unchecked(0x2764) };
|
|
///
|
|
/// assert_eq!('❤', c);
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "char_from_unchecked", since = "1.5.0")]
|
|
pub unsafe fn from_u32_unchecked(i: u32) -> char {
|
|
transmute(i)
|
|
}
|
|
|
|
#[stable(feature = "char_convert", since = "1.13.0")]
|
|
impl From<char> for u32 {
|
|
#[inline]
|
|
fn from(c: char) -> Self {
|
|
c as u32
|
|
}
|
|
}
|
|
|
|
/// Maps a byte in 0x00...0xFF to a `char` whose code point has the same value, in U+0000 to U+00FF.
|
|
///
|
|
/// Unicode is designed such that this effectively decodes bytes
|
|
/// with the character encoding that IANA calls ISO-8859-1.
|
|
/// This encoding is compatible with ASCII.
|
|
///
|
|
/// Note that this is different from ISO/IEC 8859-1 a.k.a. ISO 8859-1 (with one less hyphen),
|
|
/// which leaves some "blanks", byte values that are not assigned to any character.
|
|
/// ISO-8859-1 (the IANA one) assigns them to the C0 and C1 control codes.
|
|
///
|
|
/// Note that this is *also* different from Windows-1252 a.k.a. code page 1252,
|
|
/// which is a superset ISO/IEC 8859-1 that assigns some (not all!) blanks
|
|
/// to punctuation and various Latin characters.
|
|
///
|
|
/// To confuse things further, [on the Web](https://encoding.spec.whatwg.org/)
|
|
/// `ascii`, `iso-8859-1`, and `windows-1252` are all aliases
|
|
/// for a superset of Windows-1252 that fills the remaining blanks with corresponding
|
|
/// C0 and C1 control codes.
|
|
#[stable(feature = "char_convert", since = "1.13.0")]
|
|
impl From<u8> for char {
|
|
#[inline]
|
|
fn from(i: u8) -> Self {
|
|
i as char
|
|
}
|
|
}
|
|
|
|
|
|
/// An error which can be returned when parsing a char.
|
|
#[stable(feature = "char_from_str", since = "1.20.0")]
|
|
#[derive(Clone, Debug, PartialEq, Eq)]
|
|
pub struct ParseCharError {
|
|
kind: CharErrorKind,
|
|
}
|
|
|
|
impl ParseCharError {
|
|
#[unstable(feature = "char_error_internals",
|
|
reason = "this method should not be available publicly",
|
|
issue = "0")]
|
|
#[doc(hidden)]
|
|
pub fn __description(&self) -> &str {
|
|
match self.kind {
|
|
CharErrorKind::EmptyString => {
|
|
"cannot parse char from empty string"
|
|
},
|
|
CharErrorKind::TooManyChars => "too many characters in string"
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
|
|
enum CharErrorKind {
|
|
EmptyString,
|
|
TooManyChars,
|
|
}
|
|
|
|
#[stable(feature = "char_from_str", since = "1.20.0")]
|
|
impl fmt::Display for ParseCharError {
|
|
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
|
self.__description().fmt(f)
|
|
}
|
|
}
|
|
|
|
|
|
#[stable(feature = "char_from_str", since = "1.20.0")]
|
|
impl FromStr for char {
|
|
type Err = ParseCharError;
|
|
|
|
#[inline]
|
|
fn from_str(s: &str) -> Result<Self, Self::Err> {
|
|
let mut chars = s.chars();
|
|
match (chars.next(), chars.next()) {
|
|
(None, _) => {
|
|
Err(ParseCharError { kind: CharErrorKind::EmptyString })
|
|
},
|
|
(Some(c), None) => Ok(c),
|
|
_ => {
|
|
Err(ParseCharError { kind: CharErrorKind::TooManyChars })
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
#[unstable(feature = "try_from", issue = "33417")]
|
|
impl TryFrom<u32> for char {
|
|
type Error = CharTryFromError;
|
|
|
|
#[inline]
|
|
fn try_from(i: u32) -> Result<Self, Self::Error> {
|
|
if (i > MAX as u32) || (i >= 0xD800 && i <= 0xDFFF) {
|
|
Err(CharTryFromError(()))
|
|
} else {
|
|
Ok(unsafe { from_u32_unchecked(i) })
|
|
}
|
|
}
|
|
}
|
|
|
|
/// The error type returned when a conversion from u32 to char fails.
|
|
#[unstable(feature = "try_from", issue = "33417")]
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
|
|
pub struct CharTryFromError(());
|
|
|
|
#[unstable(feature = "try_from", issue = "33417")]
|
|
impl fmt::Display for CharTryFromError {
|
|
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
|
"converted integer out of range for `char`".fmt(f)
|
|
}
|
|
}
|
|
|
|
/// Converts a digit in the given radix to a `char`.
|
|
///
|
|
/// A 'radix' here is sometimes also called a 'base'. A radix of two
|
|
/// indicates a binary number, a radix of ten, decimal, and a radix of
|
|
/// sixteen, hexadecimal, to give some common values. Arbitrary
|
|
/// radices are supported.
|
|
///
|
|
/// `from_digit()` will return `None` if the input is not a digit in
|
|
/// the given radix.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// Panics if given a radix larger than 36.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// Basic usage:
|
|
///
|
|
/// ```
|
|
/// use std::char;
|
|
///
|
|
/// let c = char::from_digit(4, 10);
|
|
///
|
|
/// assert_eq!(Some('4'), c);
|
|
///
|
|
/// // Decimal 11 is a single digit in base 16
|
|
/// let c = char::from_digit(11, 16);
|
|
///
|
|
/// assert_eq!(Some('b'), c);
|
|
/// ```
|
|
///
|
|
/// Returning `None` when the input is not a digit:
|
|
///
|
|
/// ```
|
|
/// use std::char;
|
|
///
|
|
/// let c = char::from_digit(20, 10);
|
|
///
|
|
/// assert_eq!(None, c);
|
|
/// ```
|
|
///
|
|
/// Passing a large radix, causing a panic:
|
|
///
|
|
/// ```
|
|
/// use std::thread;
|
|
/// use std::char;
|
|
///
|
|
/// let result = thread::spawn(|| {
|
|
/// // this panics
|
|
/// let c = char::from_digit(1, 37);
|
|
/// }).join();
|
|
///
|
|
/// assert!(result.is_err());
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn from_digit(num: u32, radix: u32) -> Option<char> {
|
|
if radix > 36 {
|
|
panic!("from_digit: radix is too high (maximum 36)");
|
|
}
|
|
if num < radix {
|
|
let num = num as u8;
|
|
if num < 10 {
|
|
Some((b'0' + num) as char)
|
|
} else {
|
|
Some((b'a' + num - 10) as char)
|
|
}
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
|
|
// NB: the stabilization and documentation for this trait is in
|
|
// unicode/char.rs, not here
|
|
#[allow(missing_docs)] // docs in libunicode/u_char.rs
|
|
#[doc(hidden)]
|
|
#[unstable(feature = "core_char_ext",
|
|
reason = "the stable interface is `impl char` in later crate",
|
|
issue = "32110")]
|
|
pub trait CharExt {
|
|
#[stable(feature = "core", since = "1.6.0")]
|
|
fn is_digit(self, radix: u32) -> bool;
|
|
#[stable(feature = "core", since = "1.6.0")]
|
|
fn to_digit(self, radix: u32) -> Option<u32>;
|
|
#[stable(feature = "core", since = "1.6.0")]
|
|
fn escape_unicode(self) -> EscapeUnicode;
|
|
#[stable(feature = "core", since = "1.6.0")]
|
|
fn escape_default(self) -> EscapeDefault;
|
|
#[stable(feature = "char_escape_debug", since = "1.20.0")]
|
|
fn escape_debug(self) -> EscapeDebug;
|
|
#[stable(feature = "core", since = "1.6.0")]
|
|
fn len_utf8(self) -> usize;
|
|
#[stable(feature = "core", since = "1.6.0")]
|
|
fn len_utf16(self) -> usize;
|
|
#[stable(feature = "unicode_encode_char", since = "1.15.0")]
|
|
fn encode_utf8(self, dst: &mut [u8]) -> &mut str;
|
|
#[stable(feature = "unicode_encode_char", since = "1.15.0")]
|
|
fn encode_utf16(self, dst: &mut [u16]) -> &mut [u16];
|
|
}
|
|
|
|
#[stable(feature = "core", since = "1.6.0")]
|
|
impl CharExt for char {
|
|
#[inline]
|
|
fn is_digit(self, radix: u32) -> bool {
|
|
self.to_digit(radix).is_some()
|
|
}
|
|
|
|
#[inline]
|
|
fn to_digit(self, radix: u32) -> Option<u32> {
|
|
if radix > 36 {
|
|
panic!("to_digit: radix is too high (maximum 36)");
|
|
}
|
|
let val = match self {
|
|
'0' ... '9' => self as u32 - '0' as u32,
|
|
'a' ... 'z' => self as u32 - 'a' as u32 + 10,
|
|
'A' ... 'Z' => self as u32 - 'A' as u32 + 10,
|
|
_ => return None,
|
|
};
|
|
if val < radix { Some(val) }
|
|
else { None }
|
|
}
|
|
|
|
#[inline]
|
|
fn escape_unicode(self) -> EscapeUnicode {
|
|
let c = self as u32;
|
|
|
|
// or-ing 1 ensures that for c==0 the code computes that one
|
|
// digit should be printed and (which is the same) avoids the
|
|
// (31 - 32) underflow
|
|
let msb = 31 - (c | 1).leading_zeros();
|
|
|
|
// the index of the most significant hex digit
|
|
let ms_hex_digit = msb / 4;
|
|
EscapeUnicode {
|
|
c: self,
|
|
state: EscapeUnicodeState::Backslash,
|
|
hex_digit_idx: ms_hex_digit as usize,
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn escape_default(self) -> EscapeDefault {
|
|
let init_state = match self {
|
|
'\t' => EscapeDefaultState::Backslash('t'),
|
|
'\r' => EscapeDefaultState::Backslash('r'),
|
|
'\n' => EscapeDefaultState::Backslash('n'),
|
|
'\\' | '\'' | '"' => EscapeDefaultState::Backslash(self),
|
|
'\x20' ... '\x7e' => EscapeDefaultState::Char(self),
|
|
_ => EscapeDefaultState::Unicode(self.escape_unicode())
|
|
};
|
|
EscapeDefault { state: init_state }
|
|
}
|
|
|
|
#[inline]
|
|
fn escape_debug(self) -> EscapeDebug {
|
|
let init_state = match self {
|
|
'\t' => EscapeDefaultState::Backslash('t'),
|
|
'\r' => EscapeDefaultState::Backslash('r'),
|
|
'\n' => EscapeDefaultState::Backslash('n'),
|
|
'\\' | '\'' | '"' => EscapeDefaultState::Backslash(self),
|
|
c if is_printable(c) => EscapeDefaultState::Char(c),
|
|
c => EscapeDefaultState::Unicode(c.escape_unicode()),
|
|
};
|
|
EscapeDebug(EscapeDefault { state: init_state })
|
|
}
|
|
|
|
#[inline]
|
|
fn len_utf8(self) -> usize {
|
|
let code = self as u32;
|
|
if code < MAX_ONE_B {
|
|
1
|
|
} else if code < MAX_TWO_B {
|
|
2
|
|
} else if code < MAX_THREE_B {
|
|
3
|
|
} else {
|
|
4
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn len_utf16(self) -> usize {
|
|
let ch = self as u32;
|
|
if (ch & 0xFFFF) == ch { 1 } else { 2 }
|
|
}
|
|
|
|
#[inline]
|
|
fn encode_utf8(self, dst: &mut [u8]) -> &mut str {
|
|
let code = self as u32;
|
|
unsafe {
|
|
let len =
|
|
if code < MAX_ONE_B && !dst.is_empty() {
|
|
*dst.get_unchecked_mut(0) = code as u8;
|
|
1
|
|
} else if code < MAX_TWO_B && dst.len() >= 2 {
|
|
*dst.get_unchecked_mut(0) = (code >> 6 & 0x1F) as u8 | TAG_TWO_B;
|
|
*dst.get_unchecked_mut(1) = (code & 0x3F) as u8 | TAG_CONT;
|
|
2
|
|
} else if code < MAX_THREE_B && dst.len() >= 3 {
|
|
*dst.get_unchecked_mut(0) = (code >> 12 & 0x0F) as u8 | TAG_THREE_B;
|
|
*dst.get_unchecked_mut(1) = (code >> 6 & 0x3F) as u8 | TAG_CONT;
|
|
*dst.get_unchecked_mut(2) = (code & 0x3F) as u8 | TAG_CONT;
|
|
3
|
|
} else if dst.len() >= 4 {
|
|
*dst.get_unchecked_mut(0) = (code >> 18 & 0x07) as u8 | TAG_FOUR_B;
|
|
*dst.get_unchecked_mut(1) = (code >> 12 & 0x3F) as u8 | TAG_CONT;
|
|
*dst.get_unchecked_mut(2) = (code >> 6 & 0x3F) as u8 | TAG_CONT;
|
|
*dst.get_unchecked_mut(3) = (code & 0x3F) as u8 | TAG_CONT;
|
|
4
|
|
} else {
|
|
panic!("encode_utf8: need {} bytes to encode U+{:X}, but the buffer has {}",
|
|
from_u32_unchecked(code).len_utf8(),
|
|
code,
|
|
dst.len())
|
|
};
|
|
from_utf8_unchecked_mut(dst.get_unchecked_mut(..len))
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn encode_utf16(self, dst: &mut [u16]) -> &mut [u16] {
|
|
let mut code = self as u32;
|
|
unsafe {
|
|
if (code & 0xFFFF) == code && !dst.is_empty() {
|
|
// The BMP falls through (assuming non-surrogate, as it should)
|
|
*dst.get_unchecked_mut(0) = code as u16;
|
|
slice::from_raw_parts_mut(dst.as_mut_ptr(), 1)
|
|
} else if dst.len() >= 2 {
|
|
// Supplementary planes break into surrogates.
|
|
code -= 0x1_0000;
|
|
*dst.get_unchecked_mut(0) = 0xD800 | ((code >> 10) as u16);
|
|
*dst.get_unchecked_mut(1) = 0xDC00 | ((code as u16) & 0x3FF);
|
|
slice::from_raw_parts_mut(dst.as_mut_ptr(), 2)
|
|
} else {
|
|
panic!("encode_utf16: need {} units to encode U+{:X}, but the buffer has {}",
|
|
from_u32_unchecked(code).len_utf16(),
|
|
code,
|
|
dst.len())
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Returns an iterator that yields the hexadecimal Unicode escape of a
|
|
/// character, as `char`s.
|
|
///
|
|
/// This `struct` is created by the [`escape_unicode`] method on [`char`]. See
|
|
/// its documentation for more.
|
|
///
|
|
/// [`escape_unicode`]: ../../std/primitive.char.html#method.escape_unicode
|
|
/// [`char`]: ../../std/primitive.char.html
|
|
#[derive(Clone, Debug)]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub struct EscapeUnicode {
|
|
c: char,
|
|
state: EscapeUnicodeState,
|
|
|
|
// The index of the next hex digit to be printed (0 if none),
|
|
// i.e. the number of remaining hex digits to be printed;
|
|
// increasing from the least significant digit: 0x543210
|
|
hex_digit_idx: usize,
|
|
}
|
|
|
|
// The enum values are ordered so that their representation is the
|
|
// same as the remaining length (besides the hexadecimal digits). This
|
|
// likely makes `len()` a single load from memory) and inline-worth.
|
|
#[derive(Clone, Debug)]
|
|
enum EscapeUnicodeState {
|
|
Done,
|
|
RightBrace,
|
|
Value,
|
|
LeftBrace,
|
|
Type,
|
|
Backslash,
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl Iterator for EscapeUnicode {
|
|
type Item = char;
|
|
|
|
fn next(&mut self) -> Option<char> {
|
|
match self.state {
|
|
EscapeUnicodeState::Backslash => {
|
|
self.state = EscapeUnicodeState::Type;
|
|
Some('\\')
|
|
}
|
|
EscapeUnicodeState::Type => {
|
|
self.state = EscapeUnicodeState::LeftBrace;
|
|
Some('u')
|
|
}
|
|
EscapeUnicodeState::LeftBrace => {
|
|
self.state = EscapeUnicodeState::Value;
|
|
Some('{')
|
|
}
|
|
EscapeUnicodeState::Value => {
|
|
let hex_digit = ((self.c as u32) >> (self.hex_digit_idx * 4)) & 0xf;
|
|
let c = from_digit(hex_digit, 16).unwrap();
|
|
if self.hex_digit_idx == 0 {
|
|
self.state = EscapeUnicodeState::RightBrace;
|
|
} else {
|
|
self.hex_digit_idx -= 1;
|
|
}
|
|
Some(c)
|
|
}
|
|
EscapeUnicodeState::RightBrace => {
|
|
self.state = EscapeUnicodeState::Done;
|
|
Some('}')
|
|
}
|
|
EscapeUnicodeState::Done => None,
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
let n = self.len();
|
|
(n, Some(n))
|
|
}
|
|
|
|
#[inline]
|
|
fn count(self) -> usize {
|
|
self.len()
|
|
}
|
|
|
|
fn last(self) -> Option<char> {
|
|
match self.state {
|
|
EscapeUnicodeState::Done => None,
|
|
|
|
EscapeUnicodeState::RightBrace |
|
|
EscapeUnicodeState::Value |
|
|
EscapeUnicodeState::LeftBrace |
|
|
EscapeUnicodeState::Type |
|
|
EscapeUnicodeState::Backslash => Some('}'),
|
|
}
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "exact_size_escape", since = "1.11.0")]
|
|
impl ExactSizeIterator for EscapeUnicode {
|
|
#[inline]
|
|
fn len(&self) -> usize {
|
|
// The match is a single memory access with no branching
|
|
self.hex_digit_idx + match self.state {
|
|
EscapeUnicodeState::Done => 0,
|
|
EscapeUnicodeState::RightBrace => 1,
|
|
EscapeUnicodeState::Value => 2,
|
|
EscapeUnicodeState::LeftBrace => 3,
|
|
EscapeUnicodeState::Type => 4,
|
|
EscapeUnicodeState::Backslash => 5,
|
|
}
|
|
}
|
|
}
|
|
|
|
#[unstable(feature = "fused", issue = "35602")]
|
|
impl FusedIterator for EscapeUnicode {}
|
|
|
|
#[stable(feature = "char_struct_display", since = "1.16.0")]
|
|
impl fmt::Display for EscapeUnicode {
|
|
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
|
for c in self.clone() {
|
|
f.write_char(c)?;
|
|
}
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
/// An iterator that yields the literal escape code of a `char`.
|
|
///
|
|
/// This `struct` is created by the [`escape_default`] method on [`char`]. See
|
|
/// its documentation for more.
|
|
///
|
|
/// [`escape_default`]: ../../std/primitive.char.html#method.escape_default
|
|
/// [`char`]: ../../std/primitive.char.html
|
|
#[derive(Clone, Debug)]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub struct EscapeDefault {
|
|
state: EscapeDefaultState
|
|
}
|
|
|
|
#[derive(Clone, Debug)]
|
|
enum EscapeDefaultState {
|
|
Done,
|
|
Char(char),
|
|
Backslash(char),
|
|
Unicode(EscapeUnicode),
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl Iterator for EscapeDefault {
|
|
type Item = char;
|
|
|
|
fn next(&mut self) -> Option<char> {
|
|
match self.state {
|
|
EscapeDefaultState::Backslash(c) => {
|
|
self.state = EscapeDefaultState::Char(c);
|
|
Some('\\')
|
|
}
|
|
EscapeDefaultState::Char(c) => {
|
|
self.state = EscapeDefaultState::Done;
|
|
Some(c)
|
|
}
|
|
EscapeDefaultState::Done => None,
|
|
EscapeDefaultState::Unicode(ref mut iter) => iter.next(),
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
let n = self.len();
|
|
(n, Some(n))
|
|
}
|
|
|
|
#[inline]
|
|
fn count(self) -> usize {
|
|
self.len()
|
|
}
|
|
|
|
fn nth(&mut self, n: usize) -> Option<char> {
|
|
match self.state {
|
|
EscapeDefaultState::Backslash(c) if n == 0 => {
|
|
self.state = EscapeDefaultState::Char(c);
|
|
Some('\\')
|
|
},
|
|
EscapeDefaultState::Backslash(c) if n == 1 => {
|
|
self.state = EscapeDefaultState::Done;
|
|
Some(c)
|
|
},
|
|
EscapeDefaultState::Backslash(_) => {
|
|
self.state = EscapeDefaultState::Done;
|
|
None
|
|
},
|
|
EscapeDefaultState::Char(c) => {
|
|
self.state = EscapeDefaultState::Done;
|
|
|
|
if n == 0 {
|
|
Some(c)
|
|
} else {
|
|
None
|
|
}
|
|
},
|
|
EscapeDefaultState::Done => return None,
|
|
EscapeDefaultState::Unicode(ref mut i) => return i.nth(n),
|
|
}
|
|
}
|
|
|
|
fn last(self) -> Option<char> {
|
|
match self.state {
|
|
EscapeDefaultState::Unicode(iter) => iter.last(),
|
|
EscapeDefaultState::Done => None,
|
|
EscapeDefaultState::Backslash(c) | EscapeDefaultState::Char(c) => Some(c),
|
|
}
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "exact_size_escape", since = "1.11.0")]
|
|
impl ExactSizeIterator for EscapeDefault {
|
|
fn len(&self) -> usize {
|
|
match self.state {
|
|
EscapeDefaultState::Done => 0,
|
|
EscapeDefaultState::Char(_) => 1,
|
|
EscapeDefaultState::Backslash(_) => 2,
|
|
EscapeDefaultState::Unicode(ref iter) => iter.len(),
|
|
}
|
|
}
|
|
}
|
|
|
|
#[unstable(feature = "fused", issue = "35602")]
|
|
impl FusedIterator for EscapeDefault {}
|
|
|
|
#[stable(feature = "char_struct_display", since = "1.16.0")]
|
|
impl fmt::Display for EscapeDefault {
|
|
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
|
for c in self.clone() {
|
|
f.write_char(c)?;
|
|
}
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
/// An iterator that yields the literal escape code of a `char`.
|
|
///
|
|
/// This `struct` is created by the [`escape_debug`] method on [`char`]. See its
|
|
/// documentation for more.
|
|
///
|
|
/// [`escape_debug`]: ../../std/primitive.char.html#method.escape_debug
|
|
/// [`char`]: ../../std/primitive.char.html
|
|
#[stable(feature = "char_escape_debug", since = "1.20.0")]
|
|
#[derive(Clone, Debug)]
|
|
pub struct EscapeDebug(EscapeDefault);
|
|
|
|
#[stable(feature = "char_escape_debug", since = "1.20.0")]
|
|
impl Iterator for EscapeDebug {
|
|
type Item = char;
|
|
fn next(&mut self) -> Option<char> { self.0.next() }
|
|
fn size_hint(&self) -> (usize, Option<usize>) { self.0.size_hint() }
|
|
}
|
|
|
|
#[stable(feature = "char_escape_debug", since = "1.20.0")]
|
|
impl ExactSizeIterator for EscapeDebug { }
|
|
|
|
#[unstable(feature = "fused", issue = "35602")]
|
|
impl FusedIterator for EscapeDebug {}
|
|
|
|
#[stable(feature = "char_escape_debug", since = "1.20.0")]
|
|
impl fmt::Display for EscapeDebug {
|
|
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
|
fmt::Display::fmt(&self.0, f)
|
|
}
|
|
}
|
|
|
|
|
|
|
|
/// An iterator over an iterator of bytes of the characters the bytes represent
|
|
/// as UTF-8
|
|
#[unstable(feature = "decode_utf8", issue = "33906")]
|
|
#[derive(Clone, Debug)]
|
|
pub struct DecodeUtf8<I: Iterator<Item = u8>>(::iter::Peekable<I>);
|
|
|
|
/// Decodes an `Iterator` of bytes as UTF-8.
|
|
#[unstable(feature = "decode_utf8", issue = "33906")]
|
|
#[inline]
|
|
pub fn decode_utf8<I: IntoIterator<Item = u8>>(i: I) -> DecodeUtf8<I::IntoIter> {
|
|
DecodeUtf8(i.into_iter().peekable())
|
|
}
|
|
|
|
/// `<DecodeUtf8 as Iterator>::next` returns this for an invalid input sequence.
|
|
#[unstable(feature = "decode_utf8", issue = "33906")]
|
|
#[derive(PartialEq, Eq, Debug)]
|
|
pub struct InvalidSequence(());
|
|
|
|
#[unstable(feature = "decode_utf8", issue = "33906")]
|
|
impl<I: Iterator<Item = u8>> Iterator for DecodeUtf8<I> {
|
|
type Item = Result<char, InvalidSequence>;
|
|
#[inline]
|
|
|
|
fn next(&mut self) -> Option<Result<char, InvalidSequence>> {
|
|
self.0.next().map(|first_byte| {
|
|
// Emit InvalidSequence according to
|
|
// Unicode §5.22 Best Practice for U+FFFD Substitution
|
|
// http://www.unicode.org/versions/Unicode9.0.0/ch05.pdf#G40630
|
|
|
|
// Roughly: consume at least one byte,
|
|
// then validate one byte at a time and stop before the first unexpected byte
|
|
// (which might be the valid start of the next byte sequence).
|
|
|
|
let mut code_point;
|
|
macro_rules! first_byte {
|
|
($mask: expr) => {
|
|
code_point = u32::from(first_byte & $mask)
|
|
}
|
|
}
|
|
macro_rules! continuation_byte {
|
|
() => { continuation_byte!(0x80...0xBF) };
|
|
($range: pat) => {
|
|
match self.0.peek() {
|
|
Some(&byte @ $range) => {
|
|
code_point = (code_point << 6) | u32::from(byte & 0b0011_1111);
|
|
self.0.next();
|
|
}
|
|
_ => return Err(InvalidSequence(()))
|
|
}
|
|
}
|
|
}
|
|
|
|
match first_byte {
|
|
0x00...0x7F => {
|
|
first_byte!(0b1111_1111);
|
|
}
|
|
0xC2...0xDF => {
|
|
first_byte!(0b0001_1111);
|
|
continuation_byte!();
|
|
}
|
|
0xE0 => {
|
|
first_byte!(0b0000_1111);
|
|
continuation_byte!(0xA0...0xBF); // 0x80...0x9F here are overlong
|
|
continuation_byte!();
|
|
}
|
|
0xE1...0xEC | 0xEE...0xEF => {
|
|
first_byte!(0b0000_1111);
|
|
continuation_byte!();
|
|
continuation_byte!();
|
|
}
|
|
0xED => {
|
|
first_byte!(0b0000_1111);
|
|
continuation_byte!(0x80...0x9F); // 0xA0..0xBF here are surrogates
|
|
continuation_byte!();
|
|
}
|
|
0xF0 => {
|
|
first_byte!(0b0000_0111);
|
|
continuation_byte!(0x90...0xBF); // 0x80..0x8F here are overlong
|
|
continuation_byte!();
|
|
continuation_byte!();
|
|
}
|
|
0xF1...0xF3 => {
|
|
first_byte!(0b0000_0111);
|
|
continuation_byte!();
|
|
continuation_byte!();
|
|
continuation_byte!();
|
|
}
|
|
0xF4 => {
|
|
first_byte!(0b0000_0111);
|
|
continuation_byte!(0x80...0x8F); // 0x90..0xBF here are beyond char::MAX
|
|
continuation_byte!();
|
|
continuation_byte!();
|
|
}
|
|
_ => return Err(InvalidSequence(())) // Illegal first byte, overlong, or beyond MAX
|
|
}
|
|
unsafe {
|
|
Ok(from_u32_unchecked(code_point))
|
|
}
|
|
})
|
|
}
|
|
}
|
|
|
|
#[unstable(feature = "fused", issue = "35602")]
|
|
impl<I: FusedIterator<Item = u8>> FusedIterator for DecodeUtf8<I> {}
|