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#![cfg_attr(not(feature="std"), no_std)] #![feature(try_from)] mod read; #[cfg(feature = "std")] mod write; #[cfg(feature = "std")] pub use self::write::CDBWriter; pub use self::read::*; const ENTRIES: usize = 256; const PAIR_SIZE: usize = 8; #[derive(Copy, Clone)] pub struct PosLen { pos: usize, len: usize, } impl PosLen { fn valid(&self, datalen: usize) -> bool { let data_sz = self.len.checked_mul(PAIR_SIZE); let data_end = data_sz.and_then(|sz| sz.checked_add(self.pos)); match data_end { None => false, Some(end) => end <= datalen } } } #[derive(Copy, Clone, PartialEq)] pub struct CDBHash(pub u32); impl CDBHash { fn new(d: &[u8]) -> Self { let h = d .iter() .fold(5381u32, |h, &c| (h << 5).wrapping_add(h) ^ u32::from(c)); CDBHash(h) } fn table(&self) -> usize { self.0 as usize % ENTRIES } fn slot(&self, tlen: usize) -> usize { (self.0 as usize >> 8) % tlen } } impl core::fmt::Debug for CDBHash { fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { write!(f, "CDBHash(0x{:08x})", self.0) } } impl From<CDBHash> for u32 { fn from(h: CDBHash) -> Self { h.0 } }