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author | Valentin Popov <valentin@popov.link> | 2024-01-08 00:21:28 +0300 |
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committer | Valentin Popov <valentin@popov.link> | 2024-01-08 00:21:28 +0300 |
commit | 1b6a04ca5504955c571d1c97504fb45ea0befee4 (patch) | |
tree | 7579f518b23313e8a9748a88ab6173d5e030b227 /vendor/serde/src/de/size_hint.rs | |
parent | 5ecd8cf2cba827454317368b68571df0d13d7842 (diff) | |
download | fparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.tar.xz fparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.zip |
Initial vendor packages
Signed-off-by: Valentin Popov <valentin@popov.link>
Diffstat (limited to 'vendor/serde/src/de/size_hint.rs')
-rw-r--r-- | vendor/serde/src/de/size_hint.rs | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/vendor/serde/src/de/size_hint.rs b/vendor/serde/src/de/size_hint.rs new file mode 100644 index 0000000..4a4fe25 --- /dev/null +++ b/vendor/serde/src/de/size_hint.rs @@ -0,0 +1,29 @@ +use crate::lib::*; + +pub fn from_bounds<I>(iter: &I) -> Option<usize> +where + I: Iterator, +{ + helper(iter.size_hint()) +} + +#[cfg(any(feature = "std", feature = "alloc"))] +pub fn cautious<Element>(hint: Option<usize>) -> usize { + const MAX_PREALLOC_BYTES: usize = 1024 * 1024; + + if mem::size_of::<Element>() == 0 { + 0 + } else { + cmp::min( + hint.unwrap_or(0), + MAX_PREALLOC_BYTES / mem::size_of::<Element>(), + ) + } +} + +fn helper(bounds: (usize, Option<usize>)) -> Option<usize> { + match bounds { + (lower, Some(upper)) if lower == upper => Some(upper), + _ => None, + } +} |