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#[cfg(no_str_strip_prefix)] // rustc <1.45
pub(crate) trait StripPrefixExt {
fn strip_prefix(&self, ch: char) -> Option<&str>;
}
#[cfg(no_str_strip_prefix)]
impl StripPrefixExt for str {
fn strip_prefix(&self, ch: char) -> Option<&str> {
if self.starts_with(ch) {
Some(&self[ch.len_utf8()..])
} else {
None
}
}
}
pub(crate) use crate::alloc::vec::Vec;
#[cfg(no_alloc_crate)] // rustc <1.36
pub(crate) mod alloc {
pub use std::vec;
pub mod alloc {
use std::mem;
use std::process;
#[derive(Copy, Clone)]
pub struct Layout {
size: usize,
}
impl Layout {
pub unsafe fn from_size_align_unchecked(size: usize, align: usize) -> Self {
assert_eq!(align, 2);
Layout { size }
}
}
pub unsafe fn alloc(layout: Layout) -> *mut u8 {
let len_u16 = (layout.size + 1) / 2;
let mut vec = Vec::new();
vec.reserve_exact(len_u16);
let ptr: *mut u16 = vec.as_mut_ptr();
mem::forget(vec);
ptr as *mut u8
}
pub unsafe fn dealloc(ptr: *mut u8, layout: Layout) {
let len_u16 = (layout.size + 1) / 2;
unsafe { Vec::from_raw_parts(ptr as *mut u16, 0, len_u16) };
}
pub fn handle_alloc_error(_layout: Layout) -> ! {
// This is unreachable because the alloc implementation above never
// returns null; Vec::reserve_exact would already have called std's
// internal handle_alloc_error.
process::abort();
}
}
}
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