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// Copyright (C) 2023-2024 Free Software Foundation, Inc.
//
// This file is part of the GNU Proc Macro Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
//! Public implementation details for the `TokenStream` type, such as iterators.
use bridge;
use std::convert::TryInto;
use TokenStream;
use TokenTree;
/// An iterator over [`TokenStream`]'s [`TokenTree`]s.
#[derive(Clone)]
pub struct IntoIter {
current: *const bridge::token_stream::TokenTree,
end: *const bridge::token_stream::TokenTree,
}
impl Iterator for IntoIter {
type Item = TokenTree;
fn next(&mut self) -> Option<TokenTree> {
if self.current == self.end {
None
} else {
let result = self.current;
self.current = unsafe { self.current.add(1) };
Some(unsafe { std::ptr::read(result) }.into())
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
// TODO: I'm not a fan of those casts, once #![feature(ptr_sub_ptr)]
// is implemented we may replace this line by the following:
// self.end.sub_ptr(self.current)
let remaining = self.end as usize - self.current as usize;
(remaining, Some(remaining))
}
fn count(self) -> usize {
self.end as usize - self.current as usize
}
}
impl IntoIterator for TokenStream {
type Item = TokenTree;
type IntoIter = IntoIter;
fn into_iter(self) -> IntoIter {
let capacity = self.0.size.try_into().unwrap();
IntoIter {
current: self.0.data,
end: unsafe { self.0.data.add(capacity) },
}
}
}
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