rust/src/libstd/char.rs
Luca Bruno a9a7a427a1 std: uniform modules titles for doc
This commit uniforms the short title of modules provided by libstd,
in order to make their roles more explicit when glancing at the index.

Signed-off-by: Luca Bruno <lucab@debian.org>
2013-12-27 09:49:11 +01:00

571 lines
17 KiB
Rust

// Copyright 2012-2013 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.
//! Unicode characters manipulation (`char` type)
use cast::transmute;
use option::{None, Option, Some};
use iter::{Iterator, range_step};
use str::StrSlice;
use unicode::{derived_property, property, general_category, decompose};
use to_str::ToStr;
use str;
#[cfg(test)] use str::OwnedStr;
#[cfg(not(test))] use cmp::{Eq, Ord};
#[cfg(not(test))] use default::Default;
#[cfg(not(test))] use num::Zero;
// UTF-8 ranges and tags for encoding characters
static TAG_CONT: uint = 128u;
static MAX_ONE_B: uint = 128u;
static TAG_TWO_B: uint = 192u;
static MAX_TWO_B: uint = 2048u;
static TAG_THREE_B: uint = 224u;
static MAX_THREE_B: uint = 65536u;
static TAG_FOUR_B: uint = 240u;
/*
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
pub static MAX: char = '\U0010ffff';
/// Convert from `u32` to a character.
pub fn from_u32(i: u32) -> Option<char> {
// catch out-of-bounds and surrogates
if (i > MAX as u32) || (i >= 0xD800 && i <= 0xDFFF) {
None
} else {
Some(unsafe { transmute(i) })
}
}
/// Returns whether the specified character is considered a unicode alphabetic
/// character
pub fn is_alphabetic(c: char) -> bool { derived_property::Alphabetic(c) }
#[allow(missing_doc)]
pub fn is_XID_start(c: char) -> bool { derived_property::XID_Start(c) }
#[allow(missing_doc)]
pub fn is_XID_continue(c: char) -> bool { derived_property::XID_Continue(c) }
///
/// Indicates whether a character is in lower case, defined
/// in terms of the Unicode Derived Core Property 'Lowercase'.
///
#[inline]
pub fn is_lowercase(c: char) -> bool { derived_property::Lowercase(c) }
///
/// Indicates whether a character is in upper case, defined
/// in terms of the Unicode Derived Core Property 'Uppercase'.
///
#[inline]
pub fn is_uppercase(c: char) -> bool { derived_property::Uppercase(c) }
///
/// Indicates whether a character is whitespace. Whitespace is defined in
/// terms of the Unicode Property 'White_Space'.
///
#[inline]
pub fn is_whitespace(c: char) -> bool {
// As an optimization ASCII whitespace characters are checked separately
c == ' '
|| ('\x09' <= c && c <= '\x0d')
|| property::White_Space(c)
}
///
/// Indicates whether a character is alphanumeric. Alphanumericness is
/// defined in terms of the Unicode General Categories 'Nd', 'Nl', 'No'
/// and the Derived Core Property 'Alphabetic'.
///
#[inline]
pub fn is_alphanumeric(c: char) -> bool {
derived_property::Alphabetic(c)
|| general_category::Nd(c)
|| general_category::Nl(c)
|| general_category::No(c)
}
///
/// Indicates whether a character is a control character. Control
/// characters are defined in terms of the Unicode General Category
/// 'Cc'.
///
#[inline]
pub fn is_control(c: char) -> bool { general_category::Cc(c) }
/// Indicates whether the character is numeric (Nd, Nl, or No)
#[inline]
pub fn is_digit(c: char) -> bool {
general_category::Nd(c)
|| general_category::Nl(c)
|| general_category::No(c)
}
///
/// Checks if a character parses as a numeric digit in the given radix.
/// Compared to `is_digit()`, this function only recognizes the
/// characters `0-9`, `a-z` and `A-Z`.
///
/// # Return value
///
/// Returns `true` if `c` is a valid digit under `radix`, and `false`
/// otherwise.
///
/// # Failure
///
/// Fails if given a `radix` > 36.
///
/// # Note
///
/// This just wraps `to_digit()`.
///
#[inline]
pub fn is_digit_radix(c: char, radix: uint) -> bool {
match to_digit(c, radix) {
Some(_) => true,
None => false,
}
}
///
/// Convert a char to the corresponding digit.
///
/// # Return value
///
/// If `c` is between '0' and '9', the corresponding value
/// between 0 and 9. If `c` is 'a' or 'A', 10. If `c` is
/// 'b' or 'B', 11, etc. Returns none if the char does not
/// refer to a digit in the given radix.
///
/// # Failure
///
/// Fails if given a `radix` outside the range `[0..36]`.
///
#[inline]
pub fn to_digit(c: char, radix: uint) -> Option<uint> {
if radix > 36 {
fail!("to_digit: radix {} is too high (maximum 36)", radix);
}
let val = match c {
'0' .. '9' => c as uint - ('0' as uint),
'a' .. 'z' => c as uint + 10u - ('a' as uint),
'A' .. 'Z' => c as uint + 10u - ('A' as uint),
_ => return None,
};
if val < radix { Some(val) }
else { None }
}
///
/// Converts a number to the character representing it.
///
/// # Return value
///
/// Returns `Some(char)` if `num` represents one digit under `radix`,
/// using one character of `0-9` or `a-z`, or `None` if it doesn't.
///
/// # Failure
///
/// Fails if given an `radix` > 36.
///
#[inline]
pub fn from_digit(num: uint, radix: uint) -> Option<char> {
if radix > 36 {
fail!("from_digit: radix {} is to high (maximum 36)", num);
}
if num < radix {
unsafe {
if num < 10 {
Some(transmute(('0' as uint + num) as u32))
} else {
Some(transmute(('a' as uint + num - 10u) as u32))
}
}
} else {
None
}
}
// Constants from Unicode 6.2.0 Section 3.12 Conjoining Jamo Behavior
static S_BASE: uint = 0xAC00;
static L_BASE: uint = 0x1100;
static V_BASE: uint = 0x1161;
static T_BASE: uint = 0x11A7;
static L_COUNT: uint = 19;
static V_COUNT: uint = 21;
static T_COUNT: uint = 28;
static N_COUNT: uint = (V_COUNT * T_COUNT);
static S_COUNT: uint = (L_COUNT * N_COUNT);
// Decompose a precomposed Hangul syllable
fn decompose_hangul(s: char, f: |char|) {
let si = s as uint - S_BASE;
let li = si / N_COUNT;
unsafe {
f(transmute((L_BASE + li) as u32));
let vi = (si % N_COUNT) / T_COUNT;
f(transmute((V_BASE + vi) as u32));
let ti = si % T_COUNT;
if ti > 0 {
f(transmute((T_BASE + ti) as u32));
}
}
}
/// Returns the canonical decomposition of a character.
pub fn decompose_canonical(c: char, f: |char|) {
if (c as uint) < S_BASE || (c as uint) >= (S_BASE + S_COUNT) {
decompose::canonical(c, f);
} else {
decompose_hangul(c, f);
}
}
/// Returns the compatibility decomposition of a character.
pub fn decompose_compatible(c: char, f: |char|) {
if (c as uint) < S_BASE || (c as uint) >= (S_BASE + S_COUNT) {
decompose::compatibility(c, f);
} else {
decompose_hangul(c, f);
}
}
///
/// Return the hexadecimal unicode escape of a char.
///
/// The rules are as follows:
///
/// - chars in [0,0xff] get 2-digit escapes: `\\xNN`
/// - chars in [0x100,0xffff] get 4-digit escapes: `\\uNNNN`
/// - chars above 0x10000 get 8-digit escapes: `\\UNNNNNNNN`
///
pub fn escape_unicode(c: char, f: |char|) {
// avoid calling str::to_str_radix because we don't really need to allocate
// here.
f('\\');
let pad = match () {
_ if c <= '\xff' => { f('x'); 2 }
_ if c <= '\uffff' => { f('u'); 4 }
_ => { f('U'); 8 }
};
for offset in range_step::<i32>(4 * (pad - 1), -1, -4) {
unsafe {
match ((c as i32) >> offset) & 0xf {
i @ 0 .. 9 => { f(transmute('0' as i32 + i)); }
i => { f(transmute('a' as i32 + (i - 10))); }
}
}
}
}
///
/// Return a 'default' ASCII and C++11-like char-literal escape of a char.
///
/// 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, CR and LF are escaped as '\t', '\r' and '\n' respectively.
/// - Single-quote, double-quote and backslash chars are backslash-escaped.
/// - Any other chars in the range [0x20,0x7e] are not escaped.
/// - Any other chars are given hex unicode escapes; see `escape_unicode`.
///
pub fn escape_default(c: char, f: |char|) {
match c {
'\t' => { f('\\'); f('t'); }
'\r' => { f('\\'); f('r'); }
'\n' => { f('\\'); f('n'); }
'\\' => { f('\\'); f('\\'); }
'\'' => { f('\\'); f('\''); }
'"' => { f('\\'); f('"'); }
'\x20' .. '\x7e' => { f(c); }
_ => c.escape_unicode(f),
}
}
/// Returns the amount of bytes this character would need if encoded in utf8
pub fn len_utf8_bytes(c: char) -> uint {
static MAX_ONE_B: uint = 128u;
static MAX_TWO_B: uint = 2048u;
static MAX_THREE_B: uint = 65536u;
static MAX_FOUR_B: uint = 2097152u;
let code = c as uint;
match () {
_ if code < MAX_ONE_B => 1u,
_ if code < MAX_TWO_B => 2u,
_ if code < MAX_THREE_B => 3u,
_ if code < MAX_FOUR_B => 4u,
_ => fail!("invalid character!"),
}
}
impl ToStr for char {
#[inline]
fn to_str(&self) -> ~str {
str::from_char(*self)
}
}
#[allow(missing_doc)]
pub trait Char {
fn is_alphabetic(&self) -> bool;
fn is_XID_start(&self) -> bool;
fn is_XID_continue(&self) -> bool;
fn is_lowercase(&self) -> bool;
fn is_uppercase(&self) -> bool;
fn is_whitespace(&self) -> bool;
fn is_alphanumeric(&self) -> bool;
fn is_control(&self) -> bool;
fn is_digit(&self) -> bool;
fn is_digit_radix(&self, radix: uint) -> bool;
fn to_digit(&self, radix: uint) -> Option<uint>;
fn from_digit(num: uint, radix: uint) -> Option<char>;
fn escape_unicode(&self, f: |char|);
fn escape_default(&self, f: |char|);
fn len_utf8_bytes(&self) -> uint;
/// Encodes this character as utf-8 into the provided byte-buffer. The
/// buffer must be at least 4 bytes long or a runtime failure will occur.
///
/// This will then return the number of characters written to the slice.
fn encode_utf8(&self, dst: &mut [u8]) -> uint;
}
impl Char for char {
fn is_alphabetic(&self) -> bool { is_alphabetic(*self) }
fn is_XID_start(&self) -> bool { is_XID_start(*self) }
fn is_XID_continue(&self) -> bool { is_XID_continue(*self) }
fn is_lowercase(&self) -> bool { is_lowercase(*self) }
fn is_uppercase(&self) -> bool { is_uppercase(*self) }
fn is_whitespace(&self) -> bool { is_whitespace(*self) }
fn is_alphanumeric(&self) -> bool { is_alphanumeric(*self) }
fn is_control(&self) -> bool { is_control(*self) }
fn is_digit(&self) -> bool { is_digit(*self) }
fn is_digit_radix(&self, radix: uint) -> bool { is_digit_radix(*self, radix) }
fn to_digit(&self, radix: uint) -> Option<uint> { to_digit(*self, radix) }
fn from_digit(num: uint, radix: uint) -> Option<char> { from_digit(num, radix) }
fn escape_unicode(&self, f: |char|) { escape_unicode(*self, f) }
fn escape_default(&self, f: |char|) { escape_default(*self, f) }
fn len_utf8_bytes(&self) -> uint { len_utf8_bytes(*self) }
fn encode_utf8<'a>(&self, dst: &'a mut [u8]) -> uint {
let code = *self as uint;
if code < MAX_ONE_B {
dst[0] = code as u8;
return 1;
} else if code < MAX_TWO_B {
dst[0] = (code >> 6u & 31u | TAG_TWO_B) as u8;
dst[1] = (code & 63u | TAG_CONT) as u8;
return 2;
} else if code < MAX_THREE_B {
dst[0] = (code >> 12u & 15u | TAG_THREE_B) as u8;
dst[1] = (code >> 6u & 63u | TAG_CONT) as u8;
dst[2] = (code & 63u | TAG_CONT) as u8;
return 3;
} else {
dst[0] = (code >> 18u & 7u | TAG_FOUR_B) as u8;
dst[1] = (code >> 12u & 63u | TAG_CONT) as u8;
dst[2] = (code >> 6u & 63u | TAG_CONT) as u8;
dst[3] = (code & 63u | TAG_CONT) as u8;
return 4;
}
}
}
#[cfg(not(test))]
impl Eq for char {
#[inline]
fn eq(&self, other: &char) -> bool { (*self) == (*other) }
}
#[cfg(not(test))]
impl Ord for char {
#[inline]
fn lt(&self, other: &char) -> bool { *self < *other }
}
#[cfg(not(test))]
impl Default for char {
#[inline]
fn default() -> char { '\x00' }
}
#[cfg(not(test))]
impl Zero for char {
#[inline]
fn zero() -> char { '\x00' }
#[inline]
fn is_zero(&self) -> bool { *self == '\x00' }
}
#[test]
fn test_is_lowercase() {
assert!('a'.is_lowercase());
assert!('ö'.is_lowercase());
assert!('ß'.is_lowercase());
assert!(!'Ü'.is_lowercase());
assert!(!'P'.is_lowercase());
}
#[test]
fn test_is_uppercase() {
assert!(!'h'.is_uppercase());
assert!(!'ä'.is_uppercase());
assert!(!'ß'.is_uppercase());
assert!('Ö'.is_uppercase());
assert!('T'.is_uppercase());
}
#[test]
fn test_is_whitespace() {
assert!(' '.is_whitespace());
assert!('\u2007'.is_whitespace());
assert!('\t'.is_whitespace());
assert!('\n'.is_whitespace());
assert!(!'a'.is_whitespace());
assert!(!'_'.is_whitespace());
assert!(!'\u0000'.is_whitespace());
}
#[test]
fn test_to_digit() {
assert_eq!('0'.to_digit(10u), Some(0u));
assert_eq!('1'.to_digit(2u), Some(1u));
assert_eq!('2'.to_digit(3u), Some(2u));
assert_eq!('9'.to_digit(10u), Some(9u));
assert_eq!('a'.to_digit(16u), Some(10u));
assert_eq!('A'.to_digit(16u), Some(10u));
assert_eq!('b'.to_digit(16u), Some(11u));
assert_eq!('B'.to_digit(16u), Some(11u));
assert_eq!('z'.to_digit(36u), Some(35u));
assert_eq!('Z'.to_digit(36u), Some(35u));
assert_eq!(' '.to_digit(10u), None);
assert_eq!('$'.to_digit(36u), None);
}
#[test]
fn test_is_control() {
assert!('\u0000'.is_control());
assert!('\u0003'.is_control());
assert!('\u0006'.is_control());
assert!('\u0009'.is_control());
assert!('\u007f'.is_control());
assert!('\u0092'.is_control());
assert!(!'\u0020'.is_control());
assert!(!'\u0055'.is_control());
assert!(!'\u0068'.is_control());
}
#[test]
fn test_is_digit() {
assert!('2'.is_digit());
assert!('7'.is_digit());
assert!(!'c'.is_digit());
assert!(!'i'.is_digit());
assert!(!'z'.is_digit());
assert!(!'Q'.is_digit());
}
#[test]
fn test_escape_default() {
fn string(c: char) -> ~str {
let mut result = ~"";
escape_default(c, |c| { result.push_char(c); });
return result;
}
assert_eq!(string('\n'), ~"\\n");
assert_eq!(string('\r'), ~"\\r");
assert_eq!(string('\''), ~"\\'");
assert_eq!(string('"'), ~"\\\"");
assert_eq!(string(' '), ~" ");
assert_eq!(string('a'), ~"a");
assert_eq!(string('~'), ~"~");
assert_eq!(string('\x00'), ~"\\x00");
assert_eq!(string('\x1f'), ~"\\x1f");
assert_eq!(string('\x7f'), ~"\\x7f");
assert_eq!(string('\xff'), ~"\\xff");
assert_eq!(string('\u011b'), ~"\\u011b");
assert_eq!(string('\U0001d4b6'), ~"\\U0001d4b6");
}
#[test]
fn test_escape_unicode() {
fn string(c: char) -> ~str {
let mut result = ~"";
escape_unicode(c, |c| { result.push_char(c); });
return result;
}
assert_eq!(string('\x00'), ~"\\x00");
assert_eq!(string('\n'), ~"\\x0a");
assert_eq!(string(' '), ~"\\x20");
assert_eq!(string('a'), ~"\\x61");
assert_eq!(string('\u011b'), ~"\\u011b");
assert_eq!(string('\U0001d4b6'), ~"\\U0001d4b6");
}
#[test]
fn test_to_str() {
let s = 't'.to_str();
assert_eq!(s, ~"t");
}