1336 lines
39 KiB
Rust
1336 lines
39 KiB
Rust
// Copyright 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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//! An owned, growable string that enforces that its contents are valid UTF-8.
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#![stable(feature = "rust1", since = "1.0.0")]
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use core::fmt;
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use core::hash;
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use core::iter::FromIterator;
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use core::mem;
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use core::ops::{self, Deref, Add, Index};
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use core::ptr;
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use core::slice;
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use core::str::pattern::Pattern;
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use rustc_unicode::char::{decode_utf16, REPLACEMENT_CHARACTER};
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use rustc_unicode::str as unicode_str;
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use borrow::{Cow, IntoCow};
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use range::RangeArgument;
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use str::{self, FromStr, Utf8Error, Chars};
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use vec::Vec;
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use boxed::Box;
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/// A growable string stored as a UTF-8 encoded buffer.
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#[derive(PartialOrd, Eq, Ord)]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct String {
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vec: Vec<u8>,
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}
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/// A possible error value from the `String::from_utf8` function.
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#[stable(feature = "rust1", since = "1.0.0")]
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#[derive(Debug)]
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pub struct FromUtf8Error {
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bytes: Vec<u8>,
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error: Utf8Error,
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}
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/// A possible error value from the `String::from_utf16` function.
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#[stable(feature = "rust1", since = "1.0.0")]
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#[derive(Debug)]
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pub struct FromUtf16Error(());
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impl String {
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/// Creates a new string buffer initialized with the empty string.
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///
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/// # Examples
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///
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/// ```
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/// # #![allow(unused_mut)]
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/// let mut s = String::new();
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn new() -> String {
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String {
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vec: Vec::new(),
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}
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}
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/// Creates a new string buffer with the given capacity.
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/// The string will be able to hold exactly `capacity` bytes without
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/// reallocating. If `capacity` is 0, the string will not allocate.
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///
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/// # Examples
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///
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/// ```
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/// let mut s = String::with_capacity(10);
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///
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/// // The String contains no chars, even though it has capacity for more
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/// assert_eq!(s.len(), 0);
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///
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/// // These are all done without reallocating...
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/// let cap = s.capacity();
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/// for i in 0..10 {
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/// s.push('a');
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/// }
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///
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/// assert_eq!(s.capacity(), cap);
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///
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/// // ...but this may make the vector reallocate
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/// s.push('a');
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn with_capacity(capacity: usize) -> String {
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String {
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vec: Vec::with_capacity(capacity),
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}
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}
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// HACK(japaric): with cfg(test) the inherent `[T]::to_vec` method, which is
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// required for this method definition, is not available. Since we don't
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// require this method for testing purposes, I'll just stub it
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// NB see the slice::hack module in slice.rs for more information
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#[inline]
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#[cfg(test)]
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pub fn from_str(_: &str) -> String {
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panic!("not available with cfg(test)");
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}
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/// Converts a vector of bytes to a `String`.
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///
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/// A string slice (`&str`) is made of bytes (`u8`), and a vector of bytes
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/// (`Vec<u8>`) is made of bytes, so this function converts between the
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/// two. Not all byte slices are valid `String`s, however: `String`
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/// requires that it is valid UTF-8. `from_utf8()` checks to ensure that
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/// the bytes are valid UTF-8, and then does the conversion.
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///
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/// If you are sure that the byte slice is valid UTF-8, and you don't want
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/// to incur the overhead of the validity check, there is an unsafe version
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/// of this function, [`from_utf8_unchecked()`][fromutf8], which has the
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/// same behavior but skips the check.
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///
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/// [fromutf8]: struct.String.html#method.from_utf8_unchecked
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///
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/// This method will take care to not copy the vector, for efficiency's
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/// sake.
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///
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/// If you need a `&str` instead of a `String`, consider
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/// [`str::from_utf8()`][str].
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///
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/// [str]: ../str/fn.from_utf8.html
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///
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/// # Failure
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///
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/// Returns `Err` if the slice is not UTF-8 with a description as to why the
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/// provided bytes are not UTF-8. The vector you moved in is also included.
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///
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/// # Examples
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///
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/// Basic usage:
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///
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/// ```
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/// // some bytes, in a vector
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/// let sparkle_heart = vec![240, 159, 146, 150];
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///
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/// // We know these bytes are valid, so just use `unwrap()`.
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/// let sparkle_heart = String::from_utf8(sparkle_heart).unwrap();
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///
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/// assert_eq!("💖", sparkle_heart);
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/// ```
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///
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/// Incorrect bytes:
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///
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/// ```
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/// // some invalid bytes, in a vector
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/// let sparkle_heart = vec![0, 159, 146, 150];
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///
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/// assert!(String::from_utf8(sparkle_heart).is_err());
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/// ```
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///
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/// See the docs for [`FromUtf8Error`][error] for more details on what you
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/// can do with this error.
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///
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/// [error]: struct.FromUtf8Error.html
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn from_utf8(vec: Vec<u8>) -> Result<String, FromUtf8Error> {
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match str::from_utf8(&vec) {
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Ok(..) => Ok(String { vec: vec }),
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Err(e) => Err(FromUtf8Error { bytes: vec, error: e })
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}
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}
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/// Converts a slice of bytes to a `String`, including invalid characters.
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///
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/// A string slice (`&str`) is made of bytes (`u8`), and a slice of bytes
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/// (`&[u8]`) is made of bytes, so this function converts between the two.
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/// Not all byte slices are valid string slices, however: `&str` requires
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/// that it is valid UTF-8. During this conversion, `from_utf8_lossy()`
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/// will replace any invalid UTF-8 sequences with
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/// `U+FFFD REPLACEMENT CHARACTER`, which looks like this: <20>
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///
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/// If you are sure that the byte slice is valid UTF-8, and you don't want
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/// to incur the overhead of the conversion, there is an unsafe version
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/// of this function, [`from_utf8_unchecked()`][fromutf8], which has the
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/// same behavior but skips the checks.
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///
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/// [fromutf8]: struct.String.html#method.from_utf8_unchecked
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///
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/// If you need a `&str` instead of a `String`, consider
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/// [`str::from_utf8()`][str].
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///
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/// [str]: ../str/fn.from_utf8.html
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///
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/// # Examples
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///
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/// Basic usage:
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///
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/// ```
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/// // some bytes, in a vector
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/// let sparkle_heart = vec![240, 159, 146, 150];
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///
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/// // We know these bytes are valid, so just use `unwrap()`.
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/// let sparkle_heart = String::from_utf8(sparkle_heart).unwrap();
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///
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/// assert_eq!("💖", sparkle_heart);
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/// ```
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///
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/// Incorrect bytes:
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///
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/// ```
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/// // some invalid bytes
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/// let input = b"Hello \xF0\x90\x80World";
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/// let output = String::from_utf8_lossy(input);
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///
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/// assert_eq!("Hello <20>World", output);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn from_utf8_lossy<'a>(v: &'a [u8]) -> Cow<'a, str> {
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let mut i;
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match str::from_utf8(v) {
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Ok(s) => return Cow::Borrowed(s),
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Err(e) => i = e.valid_up_to(),
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}
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const TAG_CONT_U8: u8 = 128;
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const REPLACEMENT: &'static [u8] = b"\xEF\xBF\xBD"; // U+FFFD in UTF-8
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let total = v.len();
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fn unsafe_get(xs: &[u8], i: usize) -> u8 {
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unsafe { *xs.get_unchecked(i) }
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}
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fn safe_get(xs: &[u8], i: usize, total: usize) -> u8 {
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if i >= total {
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0
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} else {
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unsafe_get(xs, i)
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}
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}
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let mut res = String::with_capacity(total);
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if i > 0 {
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unsafe {
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res.as_mut_vec().push_all(&v[..i])
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};
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}
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// subseqidx is the index of the first byte of the subsequence we're
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// looking at. It's used to copy a bunch of contiguous good codepoints
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// at once instead of copying them one by one.
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let mut subseqidx = i;
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while i < total {
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let i_ = i;
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let byte = unsafe_get(v, i);
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i += 1;
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macro_rules! error { () => ({
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unsafe {
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if subseqidx != i_ {
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res.as_mut_vec().push_all(&v[subseqidx..i_]);
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}
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subseqidx = i;
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res.as_mut_vec().push_all(REPLACEMENT);
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}
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})}
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if byte < 128 {
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// subseqidx handles this
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} else {
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let w = unicode_str::utf8_char_width(byte);
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match w {
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2 => {
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if safe_get(v, i, total) & 192 != TAG_CONT_U8 {
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error!();
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continue;
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}
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i += 1;
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}
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3 => {
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match (byte, safe_get(v, i, total)) {
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(0xE0 , 0xA0 ... 0xBF) => (),
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(0xE1 ... 0xEC, 0x80 ... 0xBF) => (),
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(0xED , 0x80 ... 0x9F) => (),
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(0xEE ... 0xEF, 0x80 ... 0xBF) => (),
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_ => {
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error!();
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continue;
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}
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}
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i += 1;
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if safe_get(v, i, total) & 192 != TAG_CONT_U8 {
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error!();
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continue;
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}
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i += 1;
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}
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4 => {
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match (byte, safe_get(v, i, total)) {
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(0xF0 , 0x90 ... 0xBF) => (),
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(0xF1 ... 0xF3, 0x80 ... 0xBF) => (),
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(0xF4 , 0x80 ... 0x8F) => (),
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_ => {
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error!();
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continue;
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}
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}
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i += 1;
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if safe_get(v, i, total) & 192 != TAG_CONT_U8 {
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error!();
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continue;
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}
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i += 1;
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if safe_get(v, i, total) & 192 != TAG_CONT_U8 {
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error!();
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continue;
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}
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i += 1;
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}
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_ => {
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error!();
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continue;
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}
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}
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}
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}
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if subseqidx < total {
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unsafe {
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res.as_mut_vec().push_all(&v[subseqidx..total])
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};
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}
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Cow::Owned(res)
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}
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/// Decode a UTF-16 encoded vector `v` into a `String`, returning `None`
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/// if `v` contains any invalid data.
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///
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/// # Examples
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///
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/// ```
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/// // 𝄞music
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/// let mut v = &mut [0xD834, 0xDD1E, 0x006d, 0x0075,
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/// 0x0073, 0x0069, 0x0063];
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/// assert_eq!(String::from_utf16(v).unwrap(),
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/// "𝄞music".to_string());
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///
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/// // 𝄞mu<invalid>ic
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/// v[4] = 0xD800;
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/// assert!(String::from_utf16(v).is_err());
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn from_utf16(v: &[u16]) -> Result<String, FromUtf16Error> {
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decode_utf16(v.iter().cloned()).collect::<Result<_, _>>().map_err(|_| FromUtf16Error(()))
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}
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/// Decode a UTF-16 encoded vector `v` into a string, replacing
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/// invalid data with the replacement character (U+FFFD).
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///
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/// # Examples
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///
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/// ```
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/// // 𝄞mus<invalid>ic<invalid>
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/// let v = &[0xD834, 0xDD1E, 0x006d, 0x0075,
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/// 0x0073, 0xDD1E, 0x0069, 0x0063,
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/// 0xD834];
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///
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/// assert_eq!(String::from_utf16_lossy(v),
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/// "𝄞mus\u{FFFD}ic\u{FFFD}".to_string());
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/// ```
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn from_utf16_lossy(v: &[u16]) -> String {
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decode_utf16(v.iter().cloned()).map(|r| r.unwrap_or(REPLACEMENT_CHARACTER)).collect()
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}
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/// Creates a new `String` from a length, capacity, and pointer.
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///
|
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/// # Safety
|
||
///
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/// This is _very_ unsafe because:
|
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///
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/// * We call `Vec::from_raw_parts` to get a `Vec<u8>`. Therefore, this
|
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/// function inherits all of its unsafety, see [its
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/// documentation](../vec/struct.Vec.html#method.from_raw_parts)
|
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/// for the invariants it expects, they also apply to this function.
|
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/// * We assume that the `Vec` contains valid UTF-8.
|
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#[inline]
|
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#[stable(feature = "rust1", since = "1.0.0")]
|
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pub unsafe fn from_raw_parts(buf: *mut u8, length: usize, capacity: usize) -> String {
|
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String {
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vec: Vec::from_raw_parts(buf, length, capacity),
|
||
}
|
||
}
|
||
|
||
/// Converts a vector of bytes to a `String` without checking that the
|
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/// string contains valid UTF-8.
|
||
///
|
||
/// See the safe version, [`from_utf8()`][fromutf8], for more.
|
||
///
|
||
/// [fromutf8]: struct.String.html#method.from_utf8
|
||
///
|
||
/// # Safety
|
||
///
|
||
/// This function is unsafe because it does not check that the bytes passed to
|
||
/// it are valid UTF-8. If this constraint is violated, undefined behavior
|
||
/// results, as the rest of Rust assumes that `String`s are valid UTF-8.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// // some bytes, in a vector
|
||
/// let sparkle_heart = vec![240, 159, 146, 150];
|
||
///
|
||
/// let sparkle_heart = unsafe {
|
||
/// String::from_utf8_unchecked(sparkle_heart)
|
||
/// };
|
||
///
|
||
/// assert_eq!("💖", sparkle_heart);
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub unsafe fn from_utf8_unchecked(bytes: Vec<u8>) -> String {
|
||
String { vec: bytes }
|
||
}
|
||
|
||
/// Returns the underlying byte buffer, encoded as UTF-8.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let s = String::from("hello");
|
||
/// let bytes = s.into_bytes();
|
||
/// assert_eq!(bytes, [104, 101, 108, 108, 111]);
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn into_bytes(self) -> Vec<u8> {
|
||
self.vec
|
||
}
|
||
|
||
/// Extracts a string slice containing the entire string.
|
||
#[inline]
|
||
#[unstable(feature = "convert",
|
||
reason = "waiting on RFC revision",
|
||
issue = "27729")]
|
||
pub fn as_str(&self) -> &str {
|
||
self
|
||
}
|
||
|
||
/// Pushes the given string onto this string buffer.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let mut s = String::from("foo");
|
||
/// s.push_str("bar");
|
||
/// assert_eq!(s, "foobar");
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn push_str(&mut self, string: &str) {
|
||
self.vec.push_all(string.as_bytes())
|
||
}
|
||
|
||
/// Returns the number of bytes that this string buffer can hold without
|
||
/// reallocating.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let s = String::with_capacity(10);
|
||
/// assert!(s.capacity() >= 10);
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn capacity(&self) -> usize {
|
||
self.vec.capacity()
|
||
}
|
||
|
||
/// Reserves capacity for at least `additional` more bytes to be inserted
|
||
/// in the given `String`. The collection may reserve more space to avoid
|
||
/// frequent reallocations.
|
||
///
|
||
/// # Panics
|
||
///
|
||
/// Panics if the new capacity overflows `usize`.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let mut s = String::new();
|
||
/// s.reserve(10);
|
||
/// assert!(s.capacity() >= 10);
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn reserve(&mut self, additional: usize) {
|
||
self.vec.reserve(additional)
|
||
}
|
||
|
||
/// Reserves the minimum capacity for exactly `additional` more bytes to be
|
||
/// inserted in the given `String`. Does nothing if the capacity is already
|
||
/// sufficient.
|
||
///
|
||
/// Note that the allocator may give the collection more space than it
|
||
/// requests. Therefore capacity can not be relied upon to be precisely
|
||
/// minimal. Prefer `reserve` if future insertions are expected.
|
||
///
|
||
/// # Panics
|
||
///
|
||
/// Panics if the new capacity overflows `usize`.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let mut s = String::new();
|
||
/// s.reserve_exact(10);
|
||
/// assert!(s.capacity() >= 10);
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn reserve_exact(&mut self, additional: usize) {
|
||
self.vec.reserve_exact(additional)
|
||
}
|
||
|
||
/// Shrinks the capacity of this string buffer to match its length.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let mut s = String::from("foo");
|
||
/// s.reserve(100);
|
||
/// assert!(s.capacity() >= 100);
|
||
/// s.shrink_to_fit();
|
||
/// assert_eq!(s.capacity(), 3);
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn shrink_to_fit(&mut self) {
|
||
self.vec.shrink_to_fit()
|
||
}
|
||
|
||
/// Adds the given character to the end of the string.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let mut s = String::from("abc");
|
||
/// s.push('1');
|
||
/// s.push('2');
|
||
/// s.push('3');
|
||
/// assert_eq!(s, "abc123");
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn push(&mut self, ch: char) {
|
||
match ch.len_utf8() {
|
||
1 => self.vec.push(ch as u8),
|
||
ch_len => {
|
||
let cur_len = self.len();
|
||
// This may use up to 4 bytes.
|
||
self.vec.reserve(ch_len);
|
||
|
||
unsafe {
|
||
// Attempt to not use an intermediate buffer by just pushing bytes
|
||
// directly onto this string.
|
||
let slice = slice::from_raw_parts_mut (
|
||
self.vec.as_mut_ptr().offset(cur_len as isize),
|
||
ch_len
|
||
);
|
||
let used = ch.encode_utf8(slice).unwrap_or(0);
|
||
self.vec.set_len(cur_len + used);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Works with the underlying buffer as a byte slice.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let s = String::from("hello");
|
||
/// assert_eq!(s.as_bytes(), [104, 101, 108, 108, 111]);
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn as_bytes(&self) -> &[u8] {
|
||
&self.vec
|
||
}
|
||
|
||
/// Shortens a string to the specified length.
|
||
///
|
||
/// # Panics
|
||
///
|
||
/// Panics if `new_len` > current length,
|
||
/// or if `new_len` is not a character boundary.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let mut s = String::from("hello");
|
||
/// s.truncate(2);
|
||
/// assert_eq!(s, "he");
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn truncate(&mut self, new_len: usize) {
|
||
assert!(self.is_char_boundary(new_len));
|
||
self.vec.truncate(new_len)
|
||
}
|
||
|
||
/// Removes the last character from the string buffer and returns it.
|
||
/// Returns `None` if this string buffer is empty.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let mut s = String::from("foo");
|
||
/// assert_eq!(s.pop(), Some('o'));
|
||
/// assert_eq!(s.pop(), Some('o'));
|
||
/// assert_eq!(s.pop(), Some('f'));
|
||
/// assert_eq!(s.pop(), None);
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn pop(&mut self) -> Option<char> {
|
||
let len = self.len();
|
||
if len == 0 {
|
||
return None
|
||
}
|
||
|
||
let ch = self.char_at_reverse(len);
|
||
unsafe {
|
||
self.vec.set_len(len - ch.len_utf8());
|
||
}
|
||
Some(ch)
|
||
}
|
||
|
||
/// Removes the character from the string buffer at byte position `idx` and
|
||
/// returns it.
|
||
///
|
||
/// # Warning
|
||
///
|
||
/// This is an O(n) operation as it requires copying every element in the
|
||
/// buffer.
|
||
///
|
||
/// # Panics
|
||
///
|
||
/// If `idx` does not lie on a character boundary, or if it is out of
|
||
/// bounds, then this function will panic.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let mut s = String::from("foo");
|
||
/// assert_eq!(s.remove(0), 'f');
|
||
/// assert_eq!(s.remove(1), 'o');
|
||
/// assert_eq!(s.remove(0), 'o');
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn remove(&mut self, idx: usize) -> char {
|
||
let len = self.len();
|
||
assert!(idx <= len);
|
||
|
||
let ch = self.char_at(idx);
|
||
let next = idx + ch.len_utf8();
|
||
unsafe {
|
||
ptr::copy(self.vec.as_ptr().offset(next as isize),
|
||
self.vec.as_mut_ptr().offset(idx as isize),
|
||
len - next);
|
||
self.vec.set_len(len - (next - idx));
|
||
}
|
||
ch
|
||
}
|
||
|
||
/// Inserts a character into the string buffer at byte position `idx`.
|
||
///
|
||
/// # Warning
|
||
///
|
||
/// This is an O(n) operation as it requires copying every element in the
|
||
/// buffer.
|
||
///
|
||
/// # Panics
|
||
///
|
||
/// If `idx` does not lie on a character boundary or is out of bounds, then
|
||
/// this function will panic.
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn insert(&mut self, idx: usize, ch: char) {
|
||
let len = self.len();
|
||
assert!(idx <= len);
|
||
assert!(self.is_char_boundary(idx));
|
||
self.vec.reserve(4);
|
||
let mut bits = [0; 4];
|
||
let amt = ch.encode_utf8(&mut bits).unwrap();
|
||
|
||
unsafe {
|
||
ptr::copy(self.vec.as_ptr().offset(idx as isize),
|
||
self.vec.as_mut_ptr().offset((idx + amt) as isize),
|
||
len - idx);
|
||
ptr::copy(bits.as_ptr(),
|
||
self.vec.as_mut_ptr().offset(idx as isize),
|
||
amt);
|
||
self.vec.set_len(len + amt);
|
||
}
|
||
}
|
||
|
||
/// Views the string buffer as a mutable sequence of bytes.
|
||
///
|
||
/// This is unsafe because it does not check
|
||
/// to ensure that the resulting string will be valid UTF-8.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let mut s = String::from("hello");
|
||
/// unsafe {
|
||
/// let vec = s.as_mut_vec();
|
||
/// assert!(vec == &[104, 101, 108, 108, 111]);
|
||
/// vec.reverse();
|
||
/// }
|
||
/// assert_eq!(s, "olleh");
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub unsafe fn as_mut_vec(&mut self) -> &mut Vec<u8> {
|
||
&mut self.vec
|
||
}
|
||
|
||
/// Returns the number of bytes in this string.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let a = "foo".to_string();
|
||
/// assert_eq!(a.len(), 3);
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn len(&self) -> usize { self.vec.len() }
|
||
|
||
/// Returns true if the string contains no bytes
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let mut v = String::new();
|
||
/// assert!(v.is_empty());
|
||
/// v.push('a');
|
||
/// assert!(!v.is_empty());
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn is_empty(&self) -> bool { self.len() == 0 }
|
||
|
||
/// Truncates the string, returning it to 0 length.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let mut s = "foo".to_string();
|
||
/// s.clear();
|
||
/// assert!(s.is_empty());
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn clear(&mut self) {
|
||
self.vec.clear()
|
||
}
|
||
|
||
/// Create a draining iterator that removes the specified range in the string
|
||
/// and yields the removed chars from start to end. The element range is
|
||
/// removed even if the iterator is not consumed until the end.
|
||
///
|
||
/// # Panics
|
||
///
|
||
/// Panics if the starting point or end point are not on character boundaries,
|
||
/// or if they are out of bounds.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// #![feature(drain)]
|
||
///
|
||
/// let mut s = String::from("α is alpha, β is beta");
|
||
/// let beta_offset = s.find('β').unwrap_or(s.len());
|
||
///
|
||
/// // Remove the range up until the β from the string
|
||
/// let t: String = s.drain(..beta_offset).collect();
|
||
/// assert_eq!(t, "α is alpha, ");
|
||
/// assert_eq!(s, "β is beta");
|
||
///
|
||
/// // A full range clears the string
|
||
/// s.drain(..);
|
||
/// assert_eq!(s, "");
|
||
/// ```
|
||
#[unstable(feature = "drain",
|
||
reason = "recently added, matches RFC",
|
||
issue = "27711")]
|
||
pub fn drain<R>(&mut self, range: R) -> Drain where R: RangeArgument<usize> {
|
||
// Memory safety
|
||
//
|
||
// The String version of Drain does not have the memory safety issues
|
||
// of the vector version. The data is just plain bytes.
|
||
// Because the range removal happens in Drop, if the Drain iterator is leaked,
|
||
// the removal will not happen.
|
||
let len = self.len();
|
||
let start = *range.start().unwrap_or(&0);
|
||
let end = *range.end().unwrap_or(&len);
|
||
|
||
// Take out two simultaneous borrows. The &mut String won't be accessed
|
||
// until iteration is over, in Drop.
|
||
let self_ptr = self as *mut _;
|
||
// slicing does the appropriate bounds checks
|
||
let chars_iter = self[start..end].chars();
|
||
|
||
Drain {
|
||
start: start,
|
||
end: end,
|
||
iter: chars_iter,
|
||
string: self_ptr,
|
||
}
|
||
}
|
||
|
||
/// Converts the string into `Box<str>`.
|
||
///
|
||
/// Note that this will drop any excess capacity.
|
||
#[stable(feature = "box_str", since = "1.4.0")]
|
||
pub fn into_boxed_str(self) -> Box<str> {
|
||
let slice = self.vec.into_boxed_slice();
|
||
unsafe { mem::transmute::<Box<[u8]>, Box<str>>(slice) }
|
||
}
|
||
|
||
/// Converts the string into `Box<str>`.
|
||
///
|
||
/// Note that this will drop any excess capacity.
|
||
#[unstable(feature = "box_str2",
|
||
reason = "recently added, matches RFC",
|
||
issue = "27785")]
|
||
#[deprecated(since = "1.4.0", reason = "renamed to `into_boxed_str`")]
|
||
pub fn into_boxed_slice(self) -> Box<str> {
|
||
self.into_boxed_str()
|
||
}
|
||
}
|
||
|
||
impl FromUtf8Error {
|
||
/// Consumes this error, returning the bytes that were attempted to make a
|
||
/// `String` with.
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn into_bytes(self) -> Vec<u8> { self.bytes }
|
||
|
||
/// Access the underlying UTF8-error that was the cause of this error.
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn utf8_error(&self) -> Utf8Error { self.error }
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl fmt::Display for FromUtf8Error {
|
||
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||
fmt::Display::fmt(&self.error, f)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl fmt::Display for FromUtf16Error {
|
||
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||
fmt::Display::fmt("invalid utf-16: lone surrogate found", f)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl Clone for String {
|
||
fn clone(&self) -> Self {
|
||
String { vec: self.vec.clone() }
|
||
}
|
||
|
||
fn clone_from(&mut self, source: &Self) {
|
||
self.vec.clone_from(&source.vec);
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl FromIterator<char> for String {
|
||
fn from_iter<I: IntoIterator<Item=char>>(iterable: I) -> String {
|
||
let mut buf = String::new();
|
||
buf.extend(iterable);
|
||
buf
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a> FromIterator<&'a str> for String {
|
||
fn from_iter<I: IntoIterator<Item=&'a str>>(iterable: I) -> String {
|
||
let mut buf = String::new();
|
||
buf.extend(iterable);
|
||
buf
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "extend_string", since = "1.4.0")]
|
||
impl FromIterator<String> for String {
|
||
fn from_iter<I: IntoIterator<Item=String>>(iterable: I) -> String {
|
||
let mut buf = String::new();
|
||
buf.extend(iterable);
|
||
buf
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl Extend<char> for String {
|
||
fn extend<I: IntoIterator<Item=char>>(&mut self, iterable: I) {
|
||
let iterator = iterable.into_iter();
|
||
let (lower_bound, _) = iterator.size_hint();
|
||
self.reserve(lower_bound);
|
||
for ch in iterator {
|
||
self.push(ch)
|
||
}
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "extend_ref", since = "1.2.0")]
|
||
impl<'a> Extend<&'a char> for String {
|
||
fn extend<I: IntoIterator<Item=&'a char>>(&mut self, iterable: I) {
|
||
self.extend(iterable.into_iter().cloned());
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a> Extend<&'a str> for String {
|
||
fn extend<I: IntoIterator<Item=&'a str>>(&mut self, iterable: I) {
|
||
for s in iterable {
|
||
self.push_str(s)
|
||
}
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "extend_string", since = "1.4.0")]
|
||
impl Extend<String> for String {
|
||
fn extend<I: IntoIterator<Item=String>>(&mut self, iterable: I) {
|
||
for s in iterable {
|
||
self.push_str(&s)
|
||
}
|
||
}
|
||
}
|
||
|
||
/// A convenience impl that delegates to the impl for `&str`
|
||
#[unstable(feature = "pattern",
|
||
reason = "API not fully fleshed out and ready to be stabilized",
|
||
issue = "27721")]
|
||
impl<'a, 'b> Pattern<'a> for &'b String {
|
||
type Searcher = <&'b str as Pattern<'a>>::Searcher;
|
||
|
||
fn into_searcher(self, haystack: &'a str) -> <&'b str as Pattern<'a>>::Searcher {
|
||
self[..].into_searcher(haystack)
|
||
}
|
||
|
||
#[inline]
|
||
fn is_contained_in(self, haystack: &'a str) -> bool {
|
||
self[..].is_contained_in(haystack)
|
||
}
|
||
|
||
#[inline]
|
||
fn is_prefix_of(self, haystack: &'a str) -> bool {
|
||
self[..].is_prefix_of(haystack)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl PartialEq for String {
|
||
#[inline]
|
||
fn eq(&self, other: &String) -> bool { PartialEq::eq(&self[..], &other[..]) }
|
||
#[inline]
|
||
fn ne(&self, other: &String) -> bool { PartialEq::ne(&self[..], &other[..]) }
|
||
}
|
||
|
||
macro_rules! impl_eq {
|
||
($lhs:ty, $rhs: ty) => {
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a, 'b> PartialEq<$rhs> for $lhs {
|
||
#[inline]
|
||
fn eq(&self, other: &$rhs) -> bool { PartialEq::eq(&self[..], &other[..]) }
|
||
#[inline]
|
||
fn ne(&self, other: &$rhs) -> bool { PartialEq::ne(&self[..], &other[..]) }
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a, 'b> PartialEq<$lhs> for $rhs {
|
||
#[inline]
|
||
fn eq(&self, other: &$lhs) -> bool { PartialEq::eq(&self[..], &other[..]) }
|
||
#[inline]
|
||
fn ne(&self, other: &$lhs) -> bool { PartialEq::ne(&self[..], &other[..]) }
|
||
}
|
||
|
||
}
|
||
}
|
||
|
||
impl_eq! { String, str }
|
||
impl_eq! { String, &'a str }
|
||
impl_eq! { Cow<'a, str>, str }
|
||
impl_eq! { Cow<'a, str>, &'b str }
|
||
impl_eq! { Cow<'a, str>, String }
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl Default for String {
|
||
#[inline]
|
||
fn default() -> String {
|
||
String::new()
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl fmt::Display for String {
|
||
#[inline]
|
||
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||
fmt::Display::fmt(&**self, f)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl fmt::Debug for String {
|
||
#[inline]
|
||
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||
fmt::Debug::fmt(&**self, f)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl hash::Hash for String {
|
||
#[inline]
|
||
fn hash<H: hash::Hasher>(&self, hasher: &mut H) {
|
||
(**self).hash(hasher)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a> Add<&'a str> for String {
|
||
type Output = String;
|
||
|
||
#[inline]
|
||
fn add(mut self, other: &str) -> String {
|
||
self.push_str(other);
|
||
self
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl ops::Index<ops::Range<usize>> for String {
|
||
type Output = str;
|
||
|
||
#[inline]
|
||
fn index(&self, index: ops::Range<usize>) -> &str {
|
||
&self[..][index]
|
||
}
|
||
}
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl ops::Index<ops::RangeTo<usize>> for String {
|
||
type Output = str;
|
||
|
||
#[inline]
|
||
fn index(&self, index: ops::RangeTo<usize>) -> &str {
|
||
&self[..][index]
|
||
}
|
||
}
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl ops::Index<ops::RangeFrom<usize>> for String {
|
||
type Output = str;
|
||
|
||
#[inline]
|
||
fn index(&self, index: ops::RangeFrom<usize>) -> &str {
|
||
&self[..][index]
|
||
}
|
||
}
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl ops::Index<ops::RangeFull> for String {
|
||
type Output = str;
|
||
|
||
#[inline]
|
||
fn index(&self, _index: ops::RangeFull) -> &str {
|
||
unsafe { str::from_utf8_unchecked(&self.vec) }
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "derefmut_for_string", since = "1.2.0")]
|
||
impl ops::IndexMut<ops::Range<usize>> for String {
|
||
#[inline]
|
||
fn index_mut(&mut self, index: ops::Range<usize>) -> &mut str {
|
||
&mut self[..][index]
|
||
}
|
||
}
|
||
#[stable(feature = "derefmut_for_string", since = "1.2.0")]
|
||
impl ops::IndexMut<ops::RangeTo<usize>> for String {
|
||
#[inline]
|
||
fn index_mut(&mut self, index: ops::RangeTo<usize>) -> &mut str {
|
||
&mut self[..][index]
|
||
}
|
||
}
|
||
#[stable(feature = "derefmut_for_string", since = "1.2.0")]
|
||
impl ops::IndexMut<ops::RangeFrom<usize>> for String {
|
||
#[inline]
|
||
fn index_mut(&mut self, index: ops::RangeFrom<usize>) -> &mut str {
|
||
&mut self[..][index]
|
||
}
|
||
}
|
||
#[stable(feature = "derefmut_for_string", since = "1.2.0")]
|
||
impl ops::IndexMut<ops::RangeFull> for String {
|
||
#[inline]
|
||
fn index_mut(&mut self, _index: ops::RangeFull) -> &mut str {
|
||
unsafe { mem::transmute(&mut *self.vec) }
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl ops::Deref for String {
|
||
type Target = str;
|
||
|
||
#[inline]
|
||
fn deref(&self) -> &str {
|
||
unsafe { str::from_utf8_unchecked(&self.vec) }
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "derefmut_for_string", since = "1.2.0")]
|
||
impl ops::DerefMut for String {
|
||
#[inline]
|
||
fn deref_mut(&mut self) -> &mut str {
|
||
unsafe { mem::transmute(&mut *self.vec) }
|
||
}
|
||
}
|
||
|
||
/// Error returned from `String::from`
|
||
#[stable(feature = "str_parse_error", since = "1.5.0")]
|
||
#[derive(Copy)]
|
||
pub enum ParseError {}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl FromStr for String {
|
||
type Err = ParseError;
|
||
#[inline]
|
||
fn from_str(s: &str) -> Result<String, ParseError> {
|
||
Ok(String::from(s))
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "str_parse_error", since = "1.5.0")]
|
||
impl Clone for ParseError {
|
||
fn clone(&self) -> ParseError {
|
||
match *self {}
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "str_parse_error", since = "1.5.0")]
|
||
impl fmt::Debug for ParseError {
|
||
fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
|
||
match *self {}
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "str_parse_error", since = "1.5.0")]
|
||
impl PartialEq for ParseError {
|
||
fn eq(&self, _: &ParseError) -> bool {
|
||
match *self {}
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "str_parse_error", since = "1.5.0")]
|
||
impl Eq for ParseError {}
|
||
|
||
/// A generic trait for converting a value to a string
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub trait ToString {
|
||
/// Converts the value of `self` to an owned string
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
fn to_string(&self) -> String;
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<T: fmt::Display + ?Sized> ToString for T {
|
||
#[inline]
|
||
fn to_string(&self) -> String {
|
||
use core::fmt::Write;
|
||
let mut buf = String::new();
|
||
let _ = buf.write_fmt(format_args!("{}", self));
|
||
buf.shrink_to_fit();
|
||
buf
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl AsRef<str> for String {
|
||
#[inline]
|
||
fn as_ref(&self) -> &str {
|
||
self
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl AsRef<[u8]> for String {
|
||
#[inline]
|
||
fn as_ref(&self) -> &[u8] {
|
||
self.as_bytes()
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a> From<&'a str> for String {
|
||
#[cfg(not(test))]
|
||
#[inline]
|
||
fn from(s: &'a str) -> String {
|
||
String { vec: <[_]>::to_vec(s.as_bytes()) }
|
||
}
|
||
|
||
// HACK(japaric): with cfg(test) the inherent `[T]::to_vec` method, which is
|
||
// required for this method definition, is not available. Since we don't
|
||
// require this method for testing purposes, I'll just stub it
|
||
// NB see the slice::hack module in slice.rs for more information
|
||
#[inline]
|
||
#[cfg(test)]
|
||
fn from(_: &str) -> String {
|
||
panic!("not available with cfg(test)");
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a> From<&'a str> for Cow<'a, str> {
|
||
#[inline]
|
||
fn from(s: &'a str) -> Cow<'a, str> {
|
||
Cow::Borrowed(s)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a> From<String> for Cow<'a, str> {
|
||
#[inline]
|
||
fn from(s: String) -> Cow<'a, str> {
|
||
Cow::Owned(s)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl Into<Vec<u8>> for String {
|
||
fn into(self) -> Vec<u8> {
|
||
self.into_bytes()
|
||
}
|
||
}
|
||
|
||
#[unstable(feature = "into_cow", reason = "may be replaced by `convert::Into`",
|
||
issue= "27735")]
|
||
impl IntoCow<'static, str> for String {
|
||
#[inline]
|
||
fn into_cow(self) -> Cow<'static, str> {
|
||
Cow::Owned(self)
|
||
}
|
||
}
|
||
|
||
#[unstable(feature = "into_cow", reason = "may be replaced by `convert::Into`",
|
||
issue = "27735")]
|
||
impl<'a> IntoCow<'a, str> for &'a str {
|
||
#[inline]
|
||
fn into_cow(self) -> Cow<'a, str> {
|
||
Cow::Borrowed(self)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl fmt::Write for String {
|
||
#[inline]
|
||
fn write_str(&mut self, s: &str) -> fmt::Result {
|
||
self.push_str(s);
|
||
Ok(())
|
||
}
|
||
|
||
#[inline]
|
||
fn write_char(&mut self, c: char) -> fmt::Result {
|
||
self.push(c);
|
||
Ok(())
|
||
}
|
||
}
|
||
|
||
/// A draining iterator for `String`.
|
||
#[unstable(feature = "drain", reason = "recently added", issue = "27711")]
|
||
pub struct Drain<'a> {
|
||
/// Will be used as &'a mut String in the destructor
|
||
string: *mut String,
|
||
/// Start of part to remove
|
||
start: usize,
|
||
/// End of part to remove
|
||
end: usize,
|
||
/// Current remaining range to remove
|
||
iter: Chars<'a>,
|
||
}
|
||
|
||
#[unstable(feature = "drain", reason = "recently added", issue = "27711")]
|
||
unsafe impl<'a> Sync for Drain<'a> {}
|
||
#[unstable(feature = "drain", reason = "recently added", issue = "27711")]
|
||
unsafe impl<'a> Send for Drain<'a> {}
|
||
|
||
#[unstable(feature = "drain", reason = "recently added", issue = "27711")]
|
||
impl<'a> Drop for Drain<'a> {
|
||
fn drop(&mut self) {
|
||
unsafe {
|
||
// Use Vec::drain. "Reaffirm" the bounds checks to avoid
|
||
// panic code being inserted again.
|
||
let self_vec = (*self.string).as_mut_vec();
|
||
if self.start <= self.end && self.end <= self_vec.len() {
|
||
self_vec.drain(self.start..self.end);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
#[unstable(feature = "drain", reason = "recently added", issue = "27711")]
|
||
impl<'a> Iterator for Drain<'a> {
|
||
type Item = char;
|
||
|
||
#[inline]
|
||
fn next(&mut self) -> Option<char> {
|
||
self.iter.next()
|
||
}
|
||
|
||
fn size_hint(&self) -> (usize, Option<usize>) {
|
||
self.iter.size_hint()
|
||
}
|
||
}
|
||
|
||
#[unstable(feature = "drain", reason = "recently added", issue = "27711")]
|
||
impl<'a> DoubleEndedIterator for Drain<'a> {
|
||
#[inline]
|
||
fn next_back(&mut self) -> Option<char> {
|
||
self.iter.next_back()
|
||
}
|
||
}
|