556 lines
17 KiB
Rust
556 lines
17 KiB
Rust
// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//
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// ignore-lexer-test FIXME #15679
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//! Unicode-intensive string manipulations.
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//!
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//! This module provides functionality to `str` that requires the Unicode methods provided by the
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//! unicode parts of the CharExt trait.
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use self::GraphemeState::*;
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use core::prelude::*;
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use core::char;
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use core::cmp;
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use core::iter::{Filter, AdditiveIterator};
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use core::mem;
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use core::num::Int;
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use core::slice;
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use core::str::Split;
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use u_char::CharExt as UCharExt; // conflicts with core::prelude::CharExt
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use tables::grapheme::GraphemeCat;
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/// An iterator over the words of a string, separated by a sequence of whitespace
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#[stable]
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pub struct Words<'a> {
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inner: Filter<&'a str, Split<'a, fn(char) -> bool>, fn(&&str) -> bool>,
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}
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/// Methods for Unicode string slices
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#[allow(missing_docs)] // docs in libcollections
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pub trait UnicodeStr {
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fn graphemes<'a>(&'a self, is_extended: bool) -> Graphemes<'a>;
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fn grapheme_indices<'a>(&'a self, is_extended: bool) -> GraphemeIndices<'a>;
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fn words<'a>(&'a self) -> Words<'a>;
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fn is_whitespace(&self) -> bool;
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fn is_alphanumeric(&self) -> bool;
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fn width(&self, is_cjk: bool) -> uint;
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fn trim<'a>(&'a self) -> &'a str;
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fn trim_left<'a>(&'a self) -> &'a str;
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fn trim_right<'a>(&'a self) -> &'a str;
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}
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impl UnicodeStr for str {
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#[inline]
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fn graphemes(&self, is_extended: bool) -> Graphemes {
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Graphemes { string: self, extended: is_extended, cat: None, catb: None }
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}
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#[inline]
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fn grapheme_indices(&self, is_extended: bool) -> GraphemeIndices {
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GraphemeIndices { start_offset: self.as_ptr() as uint, iter: self.graphemes(is_extended) }
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}
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#[inline]
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fn words(&self) -> Words {
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fn is_not_empty(s: &&str) -> bool { !s.is_empty() }
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let is_not_empty: fn(&&str) -> bool = is_not_empty; // coerce to fn pointer
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fn is_whitespace(c: char) -> bool { c.is_whitespace() }
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let is_whitespace: fn(char) -> bool = is_whitespace; // coerce to fn pointer
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Words { inner: self.split(is_whitespace).filter(is_not_empty) }
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}
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#[inline]
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fn is_whitespace(&self) -> bool { self.chars().all(|c| c.is_whitespace()) }
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#[inline]
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fn is_alphanumeric(&self) -> bool { self.chars().all(|c| c.is_alphanumeric()) }
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#[inline]
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fn width(&self, is_cjk: bool) -> uint {
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self.chars().map(|c| c.width(is_cjk).unwrap_or(0)).sum()
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}
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#[inline]
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fn trim(&self) -> &str {
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self.trim_left().trim_right()
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}
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#[inline]
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fn trim_left(&self) -> &str {
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self.trim_left_matches(|&: c: char| c.is_whitespace())
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}
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#[inline]
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fn trim_right(&self) -> &str {
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self.trim_right_matches(|&: c: char| c.is_whitespace())
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}
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}
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/// External iterator for grapheme clusters and byte offsets.
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#[derive(Clone)]
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pub struct GraphemeIndices<'a> {
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start_offset: uint,
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iter: Graphemes<'a>,
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}
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impl<'a> Iterator for GraphemeIndices<'a> {
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type Item = (uint, &'a str);
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#[inline]
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fn next(&mut self) -> Option<(uint, &'a str)> {
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self.iter.next().map(|s| (s.as_ptr() as uint - self.start_offset, s))
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}
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#[inline]
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fn size_hint(&self) -> (uint, Option<uint>) {
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self.iter.size_hint()
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}
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}
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impl<'a> DoubleEndedIterator for GraphemeIndices<'a> {
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#[inline]
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fn next_back(&mut self) -> Option<(uint, &'a str)> {
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self.iter.next_back().map(|s| (s.as_ptr() as uint - self.start_offset, s))
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}
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}
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/// External iterator for a string's
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/// [grapheme clusters](http://www.unicode.org/reports/tr29/#Grapheme_Cluster_Boundaries).
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#[derive(Clone)]
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pub struct Graphemes<'a> {
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string: &'a str,
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extended: bool,
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cat: Option<GraphemeCat>,
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catb: Option<GraphemeCat>,
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}
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// state machine for cluster boundary rules
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#[derive(PartialEq,Eq)]
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enum GraphemeState {
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Start,
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FindExtend,
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HangulL,
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HangulLV,
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HangulLVT,
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Regional,
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}
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impl<'a> Iterator for Graphemes<'a> {
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type Item = &'a str;
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#[inline]
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fn size_hint(&self) -> (uint, Option<uint>) {
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let slen = self.string.len();
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(cmp::min(slen, 1u), Some(slen))
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}
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#[inline]
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fn next(&mut self) -> Option<&'a str> {
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use tables::grapheme as gr;
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if self.string.len() == 0 {
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return None;
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}
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let mut take_curr = true;
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let mut idx = 0;
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let mut state = Start;
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let mut cat = gr::GC_Any;
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for (curr, ch) in self.string.char_indices() {
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idx = curr;
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// retrieve cached category, if any
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// We do this because most of the time we would end up
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// looking up each character twice.
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cat = match self.cat {
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None => gr::grapheme_category(ch),
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_ => self.cat.take().unwrap()
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};
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if match cat {
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gr::GC_Extend => true,
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gr::GC_SpacingMark if self.extended => true,
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_ => false
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} {
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state = FindExtend; // rule GB9/GB9a
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continue;
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}
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state = match state {
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Start if '\r' == ch => {
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let slen = self.string.len();
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let nidx = idx + 1;
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if nidx != slen && self.string.char_at(nidx) == '\n' {
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idx = nidx; // rule GB3
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}
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break; // rule GB4
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}
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Start => match cat {
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gr::GC_Control => break,
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gr::GC_L => HangulL,
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gr::GC_LV | gr::GC_V => HangulLV,
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gr::GC_LVT | gr::GC_T => HangulLVT,
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gr::GC_RegionalIndicator => Regional,
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_ => FindExtend
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},
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FindExtend => { // found non-extending when looking for extending
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take_curr = false;
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break;
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},
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HangulL => match cat { // rule GB6: L x (L|V|LV|LVT)
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gr::GC_L => continue,
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gr::GC_LV | gr::GC_V => HangulLV,
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gr::GC_LVT => HangulLVT,
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_ => {
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take_curr = false;
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break;
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}
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},
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HangulLV => match cat { // rule GB7: (LV|V) x (V|T)
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gr::GC_V => continue,
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gr::GC_T => HangulLVT,
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_ => {
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take_curr = false;
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break;
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}
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},
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HangulLVT => match cat { // rule GB8: (LVT|T) x T
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gr::GC_T => continue,
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_ => {
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take_curr = false;
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break;
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}
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},
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Regional => match cat { // rule GB8a
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gr::GC_RegionalIndicator => continue,
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_ => {
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take_curr = false;
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break;
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}
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}
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}
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}
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self.cat = if take_curr {
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idx = self.string.char_range_at(idx).next;
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None
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} else {
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Some(cat)
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};
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let retstr = self.string.slice_to(idx);
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self.string = self.string.slice_from(idx);
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Some(retstr)
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}
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}
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impl<'a> DoubleEndedIterator for Graphemes<'a> {
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#[inline]
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fn next_back(&mut self) -> Option<&'a str> {
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use tables::grapheme as gr;
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if self.string.len() == 0 {
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return None;
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}
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let mut take_curr = true;
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let mut idx = self.string.len();
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let mut previdx = idx;
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let mut state = Start;
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let mut cat = gr::GC_Any;
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for (curr, ch) in self.string.char_indices().rev() {
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previdx = idx;
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idx = curr;
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// cached category, if any
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cat = match self.catb {
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None => gr::grapheme_category(ch),
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_ => self.catb.take().unwrap()
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};
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// a matching state machine that runs *backwards* across an input string
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// note that this has some implications for the Hangul matching, since
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// we now need to know what the rightward letter is:
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//
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// Right to left, we have:
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// L x L
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// V x (L|V|LV)
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// T x (V|T|LV|LVT)
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// HangulL means the letter to the right is L
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// HangulLV means the letter to the right is V
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// HangulLVT means the letter to the right is T
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state = match state {
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Start if '\n' == ch => {
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if idx > 0 && '\r' == self.string.char_at_reverse(idx) {
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idx -= 1; // rule GB3
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}
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break; // rule GB4
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},
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Start | FindExtend => match cat {
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gr::GC_Extend => FindExtend,
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gr::GC_SpacingMark if self.extended => FindExtend,
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gr::GC_L | gr::GC_LV | gr::GC_LVT => HangulL,
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gr::GC_V => HangulLV,
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gr::GC_T => HangulLVT,
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gr::GC_RegionalIndicator => Regional,
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gr::GC_Control => {
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take_curr = Start == state;
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break;
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},
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_ => break
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},
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HangulL => match cat { // char to right is an L
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gr::GC_L => continue, // L x L is the only legal match
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_ => {
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take_curr = false;
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break;
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}
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},
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HangulLV => match cat { // char to right is a V
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gr::GC_V => continue, // V x V, right char is still V
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gr::GC_L | gr::GC_LV => HangulL, // (L|V) x V, right char is now L
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_ => {
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take_curr = false;
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break;
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}
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},
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HangulLVT => match cat { // char to right is a T
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gr::GC_T => continue, // T x T, right char is still T
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gr::GC_V => HangulLV, // V x T, right char is now V
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gr::GC_LV | gr::GC_LVT => HangulL, // (LV|LVT) x T, right char is now L
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_ => {
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take_curr = false;
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break;
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}
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},
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Regional => match cat { // rule GB8a
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gr::GC_RegionalIndicator => continue,
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_ => {
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take_curr = false;
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break;
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}
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}
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}
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}
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self.catb = if take_curr {
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None
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} else {
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idx = previdx;
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Some(cat)
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};
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let retstr = self.string.slice_from(idx);
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self.string = self.string.slice_to(idx);
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Some(retstr)
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}
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}
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// https://tools.ietf.org/html/rfc3629
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static UTF8_CHAR_WIDTH: [u8; 256] = [
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x1F
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x3F
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x5F
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x7F
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0x9F
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0xBF
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0,0,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
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2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, // 0xDF
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3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3, // 0xEF
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4,4,4,4,4,0,0,0,0,0,0,0,0,0,0,0, // 0xFF
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];
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/// Given a first byte, determine how many bytes are in this UTF-8 character
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#[inline]
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pub fn utf8_char_width(b: u8) -> uint {
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return UTF8_CHAR_WIDTH[b as uint] as uint;
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}
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/// Determines if a vector of `u16` contains valid UTF-16
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pub fn is_utf16(v: &[u16]) -> bool {
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let mut it = v.iter();
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macro_rules! next { ($ret:expr) => {
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match it.next() { Some(u) => *u, None => return $ret }
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}
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}
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loop {
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let u = next!(true);
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match char::from_u32(u as u32) {
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Some(_) => {}
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None => {
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let u2 = next!(false);
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if u < 0xD7FF || u > 0xDBFF ||
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u2 < 0xDC00 || u2 > 0xDFFF { return false; }
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}
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}
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}
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}
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/// An iterator that decodes UTF-16 encoded codepoints from a vector
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/// of `u16`s.
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#[derive(Clone)]
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pub struct Utf16Items<'a> {
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iter: slice::Iter<'a, u16>
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}
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/// The possibilities for values decoded from a `u16` stream.
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#[derive(PartialEq, Eq, Clone, Show)]
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pub enum Utf16Item {
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/// A valid codepoint.
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ScalarValue(char),
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/// An invalid surrogate without its pair.
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LoneSurrogate(u16)
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}
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impl Copy for Utf16Item {}
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impl Utf16Item {
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/// Convert `self` to a `char`, taking `LoneSurrogate`s to the
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/// replacement character (U+FFFD).
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#[inline]
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pub fn to_char_lossy(&self) -> char {
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match *self {
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Utf16Item::ScalarValue(c) => c,
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Utf16Item::LoneSurrogate(_) => '\u{FFFD}'
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}
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}
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}
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impl<'a> Iterator for Utf16Items<'a> {
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type Item = Utf16Item;
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fn next(&mut self) -> Option<Utf16Item> {
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let u = match self.iter.next() {
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Some(u) => *u,
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None => return None
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};
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if u < 0xD800 || 0xDFFF < u {
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// not a surrogate
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Some(Utf16Item::ScalarValue(unsafe {mem::transmute(u as u32)}))
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} else if u >= 0xDC00 {
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// a trailing surrogate
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Some(Utf16Item::LoneSurrogate(u))
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} else {
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// preserve state for rewinding.
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let old = self.iter;
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let u2 = match self.iter.next() {
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Some(u2) => *u2,
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// eof
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None => return Some(Utf16Item::LoneSurrogate(u))
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};
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if u2 < 0xDC00 || u2 > 0xDFFF {
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// not a trailing surrogate so we're not a valid
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// surrogate pair, so rewind to redecode u2 next time.
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self.iter = old;
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return Some(Utf16Item::LoneSurrogate(u))
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}
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// all ok, so lets decode it.
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let c = (((u - 0xD800) as u32) << 10 | (u2 - 0xDC00) as u32) + 0x1_0000;
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Some(Utf16Item::ScalarValue(unsafe {mem::transmute(c)}))
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}
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}
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#[inline]
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fn size_hint(&self) -> (uint, Option<uint>) {
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let (low, high) = self.iter.size_hint();
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// we could be entirely valid surrogates (2 elements per
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// char), or entirely non-surrogates (1 element per char)
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(low / 2, high)
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}
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}
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/// Create an iterator over the UTF-16 encoded codepoints in `v`,
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/// returning invalid surrogates as `LoneSurrogate`s.
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///
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/// # Example
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///
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/// ```rust
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/// use unicode::str::Utf16Item::{ScalarValue, LoneSurrogate};
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///
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/// // 𝄞mus<invalid>ic<invalid>
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/// let v = [0xD834, 0xDD1E, 0x006d, 0x0075,
|
|
/// 0x0073, 0xDD1E, 0x0069, 0x0063,
|
|
/// 0xD834];
|
|
///
|
|
/// assert_eq!(unicode::str::utf16_items(&v).collect::<Vec<_>>(),
|
|
/// vec![ScalarValue('𝄞'),
|
|
/// ScalarValue('m'), ScalarValue('u'), ScalarValue('s'),
|
|
/// LoneSurrogate(0xDD1E),
|
|
/// ScalarValue('i'), ScalarValue('c'),
|
|
/// LoneSurrogate(0xD834)]);
|
|
/// ```
|
|
pub fn utf16_items<'a>(v: &'a [u16]) -> Utf16Items<'a> {
|
|
Utf16Items { iter : v.iter() }
|
|
}
|
|
|
|
/// Iterator adaptor for encoding `char`s to UTF-16.
|
|
#[derive(Clone)]
|
|
pub struct Utf16Encoder<I> {
|
|
chars: I,
|
|
extra: u16
|
|
}
|
|
|
|
impl<I> Utf16Encoder<I> {
|
|
/// Create an UTF-16 encoder from any `char` iterator.
|
|
pub fn new(chars: I) -> Utf16Encoder<I> where I: Iterator<Item=char> {
|
|
Utf16Encoder { chars: chars, extra: 0 }
|
|
}
|
|
}
|
|
|
|
impl<I> Iterator for Utf16Encoder<I> where I: Iterator<Item=char> {
|
|
type Item = u16;
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<u16> {
|
|
if self.extra != 0 {
|
|
let tmp = self.extra;
|
|
self.extra = 0;
|
|
return Some(tmp);
|
|
}
|
|
|
|
let mut buf = [0u16; 2];
|
|
self.chars.next().map(|ch| {
|
|
let n = CharExt::encode_utf16(ch, buf.as_mut_slice()).unwrap_or(0);
|
|
if n == 2 { self.extra = buf[1]; }
|
|
buf[0]
|
|
})
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (uint, Option<uint>) {
|
|
let (low, high) = self.chars.size_hint();
|
|
// every char gets either one u16 or two u16,
|
|
// so this iterator is between 1 or 2 times as
|
|
// long as the underlying iterator.
|
|
(low, high.and_then(|n| n.checked_mul(2)))
|
|
}
|
|
}
|
|
|
|
impl<'a> Iterator for Words<'a> {
|
|
type Item = &'a str;
|
|
|
|
fn next(&mut self) -> Option<&'a str> { self.inner.next() }
|
|
}
|
|
impl<'a> DoubleEndedIterator for Words<'a> {
|
|
fn next_back(&mut self) -> Option<&'a str> { self.inner.next_back() }
|
|
}
|