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39 lines
1.0 KiB
39 lines
1.0 KiB
//! Extensions
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use super::*;
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use std::mem::{self, MaybeUninit};
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use std::iter;
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/// Max size of memory allowed to be allocated on the stack.
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pub const STACK_MEM_ALLOC_MAX: usize = 4096;
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pub fn vec_uninit<T>(sz: usize) -> Vec<MaybeUninit<T>>
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{
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let mut mem: Vec<T> = Vec::with_capacity(sz);
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unsafe {
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mem.set_len(sz);
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mem::transmute(mem)
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}
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}
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/// Allocate a local buffer initialised with `init`.
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pub fn alloc_local_with<T, U>(sz: usize, init: impl FnMut() -> T, within: impl FnOnce(&mut [T]) -> U) -> U
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{
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if sz > STACK_MEM_ALLOC_MAX {
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let mut memory: Vec<T> = iter::repeat_with(init).take(sz).collect();
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within(&mut memory[..])
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} else {
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stackalloc::stackalloc_with(sz, init, within)
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}
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}
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/// Allocate a local buffer initialised with `init`.
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pub fn alloc_local<T: Clone, U>(sz: usize, init: T, within: impl FnOnce(&mut [T]) -> U) -> U
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{
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if sz > STACK_MEM_ALLOC_MAX {
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let mut memory: Vec<T> = iter::repeat(init).take(sz).collect();
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within(&mut memory[..])
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} else {
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stackalloc::stackalloc(sz, init, within)
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}
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}
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