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Diffstat (limited to 'src/libcore/ascii.rs')
| -rw-r--r-- | src/libcore/ascii.rs | 154 |
1 files changed, 0 insertions, 154 deletions
diff --git a/src/libcore/ascii.rs b/src/libcore/ascii.rs deleted file mode 100644 index e78dfd1ed4a..00000000000 --- a/src/libcore/ascii.rs +++ /dev/null @@ -1,154 +0,0 @@ -//! Operations on ASCII strings and characters. -//! -//! Most string operations in Rust act on UTF-8 strings. However, at times it -//! makes more sense to only consider the ASCII character set for a specific -//! operation. -//! -//! The [`escape_default`] function provides an iterator over the bytes of an -//! escaped version of the character given. -//! -//! [`escape_default`]: fn.escape_default.html - -#![stable(feature = "core_ascii", since = "1.26.0")] - -use crate::fmt; -use crate::iter::FusedIterator; -use crate::ops::Range; -use crate::str::from_utf8_unchecked; - -/// An iterator over the escaped version of a byte. -/// -/// This `struct` is created by the [`escape_default`] function. See its -/// documentation for more. -/// -/// [`escape_default`]: fn.escape_default.html -#[stable(feature = "rust1", since = "1.0.0")] -#[derive(Clone)] -pub struct EscapeDefault { - range: Range<usize>, - data: [u8; 4], -} - -/// Returns an iterator that produces an escaped version of a `u8`. -/// -/// The default is chosen with a bias toward producing literals that are -/// legal in a variety of languages, including C++11 and similar C-family -/// languages. The exact rules are: -/// -/// * Tab is escaped as `\t`. -/// * Carriage return is escaped as `\r`. -/// * Line feed is escaped as `\n`. -/// * Single quote is escaped as `\'`. -/// * Double quote is escaped as `\"`. -/// * Backslash is escaped as `\\`. -/// * Any character in the 'printable ASCII' range `0x20` .. `0x7e` -/// inclusive is not escaped. -/// * Any other chars are given hex escapes of the form '\xNN'. -/// * Unicode escapes are never generated by this function. -/// -/// # Examples -/// -/// ``` -/// use std::ascii; -/// -/// let escaped = ascii::escape_default(b'0').next().unwrap(); -/// assert_eq!(b'0', escaped); -/// -/// let mut escaped = ascii::escape_default(b'\t'); -/// -/// assert_eq!(b'\\', escaped.next().unwrap()); -/// assert_eq!(b't', escaped.next().unwrap()); -/// -/// let mut escaped = ascii::escape_default(b'\r'); -/// -/// assert_eq!(b'\\', escaped.next().unwrap()); -/// assert_eq!(b'r', escaped.next().unwrap()); -/// -/// let mut escaped = ascii::escape_default(b'\n'); -/// -/// assert_eq!(b'\\', escaped.next().unwrap()); -/// assert_eq!(b'n', escaped.next().unwrap()); -/// -/// let mut escaped = ascii::escape_default(b'\''); -/// -/// assert_eq!(b'\\', escaped.next().unwrap()); -/// assert_eq!(b'\'', escaped.next().unwrap()); -/// -/// let mut escaped = ascii::escape_default(b'"'); -/// -/// assert_eq!(b'\\', escaped.next().unwrap()); -/// assert_eq!(b'"', escaped.next().unwrap()); -/// -/// let mut escaped = ascii::escape_default(b'\\'); -/// -/// assert_eq!(b'\\', escaped.next().unwrap()); -/// assert_eq!(b'\\', escaped.next().unwrap()); -/// -/// let mut escaped = ascii::escape_default(b'\x9d'); -/// -/// assert_eq!(b'\\', escaped.next().unwrap()); -/// assert_eq!(b'x', escaped.next().unwrap()); -/// assert_eq!(b'9', escaped.next().unwrap()); -/// assert_eq!(b'd', escaped.next().unwrap()); -/// ``` -#[stable(feature = "rust1", since = "1.0.0")] -pub fn escape_default(c: u8) -> EscapeDefault { - let (data, len) = match c { - b'\t' => ([b'\\', b't', 0, 0], 2), - b'\r' => ([b'\\', b'r', 0, 0], 2), - b'\n' => ([b'\\', b'n', 0, 0], 2), - b'\\' => ([b'\\', b'\\', 0, 0], 2), - b'\'' => ([b'\\', b'\'', 0, 0], 2), - b'"' => ([b'\\', b'"', 0, 0], 2), - b'\x20'..=b'\x7e' => ([c, 0, 0, 0], 1), - _ => ([b'\\', b'x', hexify(c >> 4), hexify(c & 0xf)], 4), - }; - - return EscapeDefault { range: 0..len, data }; - - fn hexify(b: u8) -> u8 { - match b { - 0..=9 => b'0' + b, - _ => b'a' + b - 10, - } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl Iterator for EscapeDefault { - type Item = u8; - fn next(&mut self) -> Option<u8> { - self.range.next().map(|i| self.data[i]) - } - fn size_hint(&self) -> (usize, Option<usize>) { - self.range.size_hint() - } - fn last(mut self) -> Option<u8> { - self.next_back() - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl DoubleEndedIterator for EscapeDefault { - fn next_back(&mut self) -> Option<u8> { - self.range.next_back().map(|i| self.data[i]) - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl ExactSizeIterator for EscapeDefault {} -#[stable(feature = "fused", since = "1.26.0")] -impl FusedIterator for EscapeDefault {} - -#[stable(feature = "ascii_escape_display", since = "1.39.0")] -impl fmt::Display for EscapeDefault { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - // SAFETY: ok because `escape_default` created only valid utf-8 data - f.write_str(unsafe { from_utf8_unchecked(&self.data[self.range.clone()]) }) - } -} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl fmt::Debug for EscapeDefault { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.pad("EscapeDefault { .. }") - } -} |