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https://gitlab.com/fabinfra/fabaccess/bffh.git
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29 lines
935 B
Rust
29 lines
935 B
Rust
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use std::alloc::Layout;
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use std::io::{Error, ErrorKind};
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#[inline]
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pub(crate) fn extend(layout: Layout, next: Layout) -> (Layout, usize) {
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let new_align = std::cmp::max(layout.align(), next.align());
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let pad = padding_needed_for(layout, next.align());
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let offset = layout
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.size()
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.checked_add(pad)
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.ok_or_else(|| Error::new(ErrorKind::Other, "Padding overflow check failed"))
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.unwrap();
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let new_size = offset
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.checked_add(next.size())
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.ok_or_else(|| Error::new(ErrorKind::Other, "New size can't be computed"))
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.unwrap();
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let layout = Layout::from_size_align(new_size, new_align).unwrap();
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(layout, offset)
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}
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#[inline]
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pub(crate) fn padding_needed_for(layout: Layout, align: usize) -> usize {
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let len = layout.size();
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let len_rounded_up = len.wrapping_add(align).wrapping_sub(1) & !align.wrapping_sub(1);
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len_rounded_up.wrapping_sub(len)
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}
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