60625a6ef0
Allow reverse iteration of lowercase'd/uppercase'd chars
The PR implements `DoubleEndedIterator` trait for `ToLowercase` and `ToUppercase`.
This enables reverse iteration of lowercase/uppercase variants of character sequences.
One of use cases: determining whether a char sequence is a suffix of another one.
Example:
```rust
fn endswith_ignore_case(s1: &str, s2: &str) -> bool {
for eob in s1
.chars()
.flat_map(|c| c.to_lowercase())
.rev()
.zip_longest(s2.chars().flat_map(|c| c.to_lowercase()).rev())
{
match eob {
EitherOrBoth::Both(c1, c2) => {
if c1 != c2 {
return false;
}
}
EitherOrBoth::Left(_) => return true,
EitherOrBoth::Right(_) => return false,
}
}
true
}
```
389 lines
12 KiB
Rust
389 lines
12 KiB
Rust
use std::convert::TryFrom;
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use std::str::FromStr;
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use std::{char, str};
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#[test]
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fn test_convert() {
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assert_eq!(u32::from('a'), 0x61);
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assert_eq!(u64::from('b'), 0x62);
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assert_eq!(u128::from('c'), 0x63);
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assert_eq!(char::from(b'\0'), '\0');
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assert_eq!(char::from(b'a'), 'a');
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assert_eq!(char::from(b'\xFF'), '\u{FF}');
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assert_eq!(char::try_from(0_u32), Ok('\0'));
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assert_eq!(char::try_from(0x61_u32), Ok('a'));
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assert_eq!(char::try_from(0xD7FF_u32), Ok('\u{D7FF}'));
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assert!(char::try_from(0xD800_u32).is_err());
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assert!(char::try_from(0xDFFF_u32).is_err());
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assert_eq!(char::try_from(0xE000_u32), Ok('\u{E000}'));
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assert_eq!(char::try_from(0x10FFFF_u32), Ok('\u{10FFFF}'));
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assert!(char::try_from(0x110000_u32).is_err());
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assert!(char::try_from(0xFFFF_FFFF_u32).is_err());
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}
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#[test]
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const fn test_convert_const() {
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assert!(u32::from('a') == 0x61);
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assert!(u64::from('b') == 0x62);
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assert!(u128::from('c') == 0x63);
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assert!(char::from(b'\0') == '\0');
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assert!(char::from(b'a') == 'a');
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assert!(char::from(b'\xFF') == '\u{FF}');
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}
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#[test]
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fn test_from_str() {
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assert_eq!(char::from_str("a").unwrap(), 'a');
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assert_eq!(char::from_str("\0").unwrap(), '\0');
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assert_eq!(char::from_str("\u{D7FF}").unwrap(), '\u{d7FF}');
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assert!(char::from_str("").is_err());
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assert!(char::from_str("abc").is_err());
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}
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#[test]
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fn test_is_lowercase() {
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assert!('a'.is_lowercase());
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assert!('ö'.is_lowercase());
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assert!('ß'.is_lowercase());
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assert!(!'Ü'.is_lowercase());
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assert!(!'P'.is_lowercase());
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}
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#[test]
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fn test_is_uppercase() {
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assert!(!'h'.is_uppercase());
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assert!(!'ä'.is_uppercase());
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assert!(!'ß'.is_uppercase());
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assert!('Ö'.is_uppercase());
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assert!('T'.is_uppercase());
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}
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#[test]
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fn test_is_whitespace() {
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assert!(' '.is_whitespace());
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assert!('\u{2007}'.is_whitespace());
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assert!('\t'.is_whitespace());
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assert!('\n'.is_whitespace());
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assert!(!'a'.is_whitespace());
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assert!(!'_'.is_whitespace());
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assert!(!'\u{0}'.is_whitespace());
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}
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#[test]
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fn test_to_digit() {
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assert_eq!('0'.to_digit(10), Some(0));
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assert_eq!('1'.to_digit(2), Some(1));
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assert_eq!('2'.to_digit(3), Some(2));
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assert_eq!('9'.to_digit(10), Some(9));
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assert_eq!('a'.to_digit(16), Some(10));
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assert_eq!('A'.to_digit(16), Some(10));
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assert_eq!('b'.to_digit(16), Some(11));
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assert_eq!('B'.to_digit(16), Some(11));
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assert_eq!('A'.to_digit(36), Some(10));
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assert_eq!('z'.to_digit(36), Some(35));
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assert_eq!('Z'.to_digit(36), Some(35));
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assert_eq!('['.to_digit(36), None);
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assert_eq!('`'.to_digit(36), None);
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assert_eq!('{'.to_digit(36), None);
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assert_eq!('$'.to_digit(36), None);
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assert_eq!('@'.to_digit(16), None);
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assert_eq!('G'.to_digit(16), None);
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assert_eq!('g'.to_digit(16), None);
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assert_eq!(' '.to_digit(10), None);
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assert_eq!('/'.to_digit(10), None);
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assert_eq!(':'.to_digit(10), None);
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assert_eq!(':'.to_digit(11), None);
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}
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#[test]
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fn test_to_lowercase() {
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fn lower(c: char) -> String {
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let to_lowercase = c.to_lowercase();
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assert_eq!(to_lowercase.len(), to_lowercase.count());
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let iter: String = c.to_lowercase().collect();
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let disp: String = c.to_lowercase().to_string();
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assert_eq!(iter, disp);
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let iter_rev: String = c.to_lowercase().rev().collect();
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let disp_rev: String = disp.chars().rev().collect();
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assert_eq!(iter_rev, disp_rev);
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iter
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}
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assert_eq!(lower('A'), "a");
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assert_eq!(lower('Ö'), "ö");
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assert_eq!(lower('ß'), "ß");
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assert_eq!(lower('Ü'), "ü");
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assert_eq!(lower('💩'), "💩");
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assert_eq!(lower('Σ'), "σ");
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assert_eq!(lower('Τ'), "τ");
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assert_eq!(lower('Ι'), "ι");
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assert_eq!(lower('Γ'), "γ");
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assert_eq!(lower('Μ'), "μ");
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assert_eq!(lower('Α'), "α");
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assert_eq!(lower('Σ'), "σ");
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assert_eq!(lower('Dž'), "dž");
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assert_eq!(lower('fi'), "fi");
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assert_eq!(lower('İ'), "i\u{307}");
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}
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#[test]
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fn test_to_uppercase() {
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fn upper(c: char) -> String {
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let to_uppercase = c.to_uppercase();
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assert_eq!(to_uppercase.len(), to_uppercase.count());
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let iter: String = c.to_uppercase().collect();
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let disp: String = c.to_uppercase().to_string();
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assert_eq!(iter, disp);
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let iter_rev: String = c.to_uppercase().rev().collect();
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let disp_rev: String = disp.chars().rev().collect();
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assert_eq!(iter_rev, disp_rev);
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iter
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}
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assert_eq!(upper('a'), "A");
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assert_eq!(upper('ö'), "Ö");
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assert_eq!(upper('ß'), "SS"); // not ẞ: Latin capital letter sharp s
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assert_eq!(upper('ü'), "Ü");
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assert_eq!(upper('💩'), "💩");
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assert_eq!(upper('σ'), "Σ");
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assert_eq!(upper('τ'), "Τ");
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assert_eq!(upper('ι'), "Ι");
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assert_eq!(upper('γ'), "Γ");
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assert_eq!(upper('μ'), "Μ");
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assert_eq!(upper('α'), "Α");
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assert_eq!(upper('ς'), "Σ");
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assert_eq!(upper('Dž'), "DŽ");
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assert_eq!(upper('fi'), "FI");
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assert_eq!(upper('ᾀ'), "ἈΙ");
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}
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#[test]
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fn test_is_control() {
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assert!('\u{0}'.is_control());
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assert!('\u{3}'.is_control());
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assert!('\u{6}'.is_control());
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assert!('\u{9}'.is_control());
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assert!('\u{7f}'.is_control());
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assert!('\u{92}'.is_control());
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assert!(!'\u{20}'.is_control());
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assert!(!'\u{55}'.is_control());
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assert!(!'\u{68}'.is_control());
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}
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#[test]
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fn test_is_numeric() {
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assert!('2'.is_numeric());
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assert!('7'.is_numeric());
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assert!('¾'.is_numeric());
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assert!(!'c'.is_numeric());
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assert!(!'i'.is_numeric());
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assert!(!'z'.is_numeric());
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assert!(!'Q'.is_numeric());
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}
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#[test]
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fn test_escape_debug() {
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fn string(c: char) -> String {
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let iter: String = c.escape_debug().collect();
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let disp: String = c.escape_debug().to_string();
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assert_eq!(iter, disp);
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iter
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}
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assert_eq!(string('\n'), "\\n");
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assert_eq!(string('\r'), "\\r");
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assert_eq!(string('\''), "\\'");
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assert_eq!(string('"'), "\\\"");
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assert_eq!(string(' '), " ");
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assert_eq!(string('a'), "a");
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assert_eq!(string('~'), "~");
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assert_eq!(string('é'), "é");
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assert_eq!(string('文'), "文");
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assert_eq!(string('\x00'), "\\u{0}");
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assert_eq!(string('\x1f'), "\\u{1f}");
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assert_eq!(string('\x7f'), "\\u{7f}");
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assert_eq!(string('\u{80}'), "\\u{80}");
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assert_eq!(string('\u{ff}'), "\u{ff}");
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assert_eq!(string('\u{11b}'), "\u{11b}");
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assert_eq!(string('\u{1d4b6}'), "\u{1d4b6}");
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assert_eq!(string('\u{301}'), "\\u{301}"); // combining character
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assert_eq!(string('\u{200b}'), "\\u{200b}"); // zero width space
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assert_eq!(string('\u{e000}'), "\\u{e000}"); // private use 1
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assert_eq!(string('\u{100000}'), "\\u{100000}"); // private use 2
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}
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#[test]
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fn test_escape_default() {
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fn string(c: char) -> String {
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let iter: String = c.escape_default().collect();
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let disp: String = c.escape_default().to_string();
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assert_eq!(iter, disp);
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iter
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}
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assert_eq!(string('\n'), "\\n");
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assert_eq!(string('\r'), "\\r");
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assert_eq!(string('\''), "\\'");
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assert_eq!(string('"'), "\\\"");
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assert_eq!(string(' '), " ");
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assert_eq!(string('a'), "a");
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assert_eq!(string('~'), "~");
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assert_eq!(string('é'), "\\u{e9}");
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assert_eq!(string('\x00'), "\\u{0}");
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assert_eq!(string('\x1f'), "\\u{1f}");
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assert_eq!(string('\x7f'), "\\u{7f}");
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assert_eq!(string('\u{80}'), "\\u{80}");
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assert_eq!(string('\u{ff}'), "\\u{ff}");
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assert_eq!(string('\u{11b}'), "\\u{11b}");
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assert_eq!(string('\u{1d4b6}'), "\\u{1d4b6}");
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assert_eq!(string('\u{200b}'), "\\u{200b}"); // zero width space
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assert_eq!(string('\u{e000}'), "\\u{e000}"); // private use 1
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assert_eq!(string('\u{100000}'), "\\u{100000}"); // private use 2
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}
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#[test]
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fn test_escape_unicode() {
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fn string(c: char) -> String {
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let iter: String = c.escape_unicode().collect();
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let disp: String = c.escape_unicode().to_string();
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assert_eq!(iter, disp);
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iter
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}
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assert_eq!(string('\x00'), "\\u{0}");
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assert_eq!(string('\n'), "\\u{a}");
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assert_eq!(string(' '), "\\u{20}");
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assert_eq!(string('a'), "\\u{61}");
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assert_eq!(string('\u{11b}'), "\\u{11b}");
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assert_eq!(string('\u{1d4b6}'), "\\u{1d4b6}");
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}
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#[test]
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fn test_encode_utf8() {
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fn check(input: char, expect: &[u8]) {
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let mut buf = [0; 4];
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let ptr = buf.as_ptr();
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let s = input.encode_utf8(&mut buf);
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assert_eq!(s.as_ptr() as usize, ptr as usize);
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assert!(str::from_utf8(s.as_bytes()).is_ok());
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assert_eq!(s.as_bytes(), expect);
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}
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check('x', &[0x78]);
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check('\u{e9}', &[0xc3, 0xa9]);
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check('\u{a66e}', &[0xea, 0x99, 0xae]);
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check('\u{1f4a9}', &[0xf0, 0x9f, 0x92, 0xa9]);
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}
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#[test]
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fn test_encode_utf16() {
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fn check(input: char, expect: &[u16]) {
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let mut buf = [0; 2];
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let ptr = buf.as_mut_ptr();
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let b = input.encode_utf16(&mut buf);
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assert_eq!(b.as_mut_ptr() as usize, ptr as usize);
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assert_eq!(b, expect);
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}
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check('x', &[0x0078]);
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check('\u{e9}', &[0x00e9]);
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check('\u{a66e}', &[0xa66e]);
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check('\u{1f4a9}', &[0xd83d, 0xdca9]);
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}
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#[test]
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fn test_len_utf16() {
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assert!('x'.len_utf16() == 1);
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assert!('\u{e9}'.len_utf16() == 1);
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assert!('\u{a66e}'.len_utf16() == 1);
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assert!('\u{1f4a9}'.len_utf16() == 2);
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}
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#[test]
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fn test_decode_utf16() {
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fn check(s: &[u16], expected: &[Result<char, u16>]) {
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let v = char::decode_utf16(s.iter().cloned())
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.map(|r| r.map_err(|e| e.unpaired_surrogate()))
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.collect::<Vec<_>>();
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assert_eq!(v, expected);
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}
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check(&[0xD800, 0x41, 0x42], &[Err(0xD800), Ok('A'), Ok('B')]);
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check(&[0xD800, 0], &[Err(0xD800), Ok('\0')]);
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}
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#[test]
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fn ed_iterator_specializations() {
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// Check counting
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assert_eq!('\n'.escape_default().count(), 2);
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assert_eq!('c'.escape_default().count(), 1);
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assert_eq!(' '.escape_default().count(), 1);
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assert_eq!('\\'.escape_default().count(), 2);
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assert_eq!('\''.escape_default().count(), 2);
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// Check nth
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// Check that OoB is handled correctly
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assert_eq!('\n'.escape_default().nth(2), None);
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assert_eq!('c'.escape_default().nth(1), None);
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assert_eq!(' '.escape_default().nth(1), None);
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assert_eq!('\\'.escape_default().nth(2), None);
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assert_eq!('\''.escape_default().nth(2), None);
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// Check the first char
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assert_eq!('\n'.escape_default().nth(0), Some('\\'));
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assert_eq!('c'.escape_default().nth(0), Some('c'));
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assert_eq!(' '.escape_default().nth(0), Some(' '));
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assert_eq!('\\'.escape_default().nth(0), Some('\\'));
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assert_eq!('\''.escape_default().nth(0), Some('\\'));
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// Check the second char
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assert_eq!('\n'.escape_default().nth(1), Some('n'));
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assert_eq!('\\'.escape_default().nth(1), Some('\\'));
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assert_eq!('\''.escape_default().nth(1), Some('\''));
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// Check the last char
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assert_eq!('\n'.escape_default().last(), Some('n'));
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assert_eq!('c'.escape_default().last(), Some('c'));
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assert_eq!(' '.escape_default().last(), Some(' '));
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assert_eq!('\\'.escape_default().last(), Some('\\'));
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assert_eq!('\''.escape_default().last(), Some('\''));
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}
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#[test]
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fn eu_iterator_specializations() {
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fn check(c: char) {
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let len = c.escape_unicode().count();
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// Check OoB
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assert_eq!(c.escape_unicode().nth(len), None);
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// For all possible in-bound offsets
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let mut iter = c.escape_unicode();
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for offset in 0..len {
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// Check last
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assert_eq!(iter.clone().last(), Some('}'));
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// Check len
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assert_eq!(iter.len(), len - offset);
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// Check size_hint (= len in ExactSizeIterator)
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assert_eq!(iter.size_hint(), (iter.len(), Some(iter.len())));
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// Check counting
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assert_eq!(iter.clone().count(), len - offset);
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// Check nth
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assert_eq!(c.escape_unicode().nth(offset), iter.next());
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}
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// Check post-last
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assert_eq!(iter.clone().last(), None);
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assert_eq!(iter.clone().count(), 0);
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}
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check('\u{0}');
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check('\u{1}');
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check('\u{12}');
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check('\u{123}');
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check('\u{1234}');
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check('\u{12340}');
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check('\u{10FFFF}');
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}
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