Add nvim_oxi::string! macro that produces nvim_oxi::Strings
#186
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crates/types/src/string.rs
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| // Same as `let n = (required_size as f64 / self.size as f64).ceil()` but using integer | ||
| // arithmetic. | ||
| // | ||
| // `n` is the smallest number that, when multiplied by `self.size`, gives a | ||
| // number that is at least equal to `required_size`. | ||
| let n = (required_size + self.size - 1) / self.size; | ||
| let new_size = self.size * n; | ||
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| self.data = unsafe { | ||
| libc::realloc(self.data as *mut _, new_size) | ||
| as *mut ffi::c_char | ||
| }; | ||
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| self.size = new_size; | ||
| debug_assert!(self.len < self.size) |
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I think this strategy is a bit too conservative, and might lead to unnecessary re-allocations. Vec's strategy is to just double the capacity until it's greater than the new length.
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Ah, I thought vec multiplies by current len a certain number of times, but doubling each time makes much more sense, because the initial length might be pretty small.
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What I meant is that we always keep the capacity a multiple of 2. It starts not as len + 1, but as the smallest power of 2 that's greater or equal than the slice's length (with a minumum of 4). To get the new capacity, we just:
let n = (required_cap - 1).ilog2() + 1;
let new_cap = 2_usize.pow(n);or even:
loop {
self.cap *= 2;
if required_cap <= self.cap {
break;
}
}
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@noib3 I've pushed the changes, let me if anything else needs to be updated. |
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Hi, sorry for the long delay. If you still want to finish the PR, I'd merge it after this is addressed and all the commits are squashed. |
types: rename `size` field to `len` in `String` types: remove `#[repr(C)]` from `StringBuilder` types: use the `String` type itself instead of redefining the fields in `StringBuilder` types: a less conservative reallocation for `StringBuilder` types: update comment on deallocation in `StringBuilder` types(string): keep the size of allocation in string to a power of 2.
SCJangra
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No problem
Done |
Closes #184