Indexing cache_table::CacheTable on 32-bit systems may cause overflow

[ivan-r-sigaev]

chess/src/cache_table.rs

Line 39 in 0e538fb

let entry = unsafe { *self.table.get_unchecked((hash as usize) & self.mask) };

chess/src/cache_table.rs

Line 50 in 0e538fb

let e = unsafe { self.table.get_unchecked_mut((hash as usize) & self.mask) };

chess/src/cache_table.rs

Line 83 in 0e538fb

let e = unsafe { self.table.get_unchecked_mut((hash as usize) & self.mask) };

On 32-bit systems hash as usize will overflow if the value of hash is greater than u32::MAX.

This overflow is mostly harmless in release mode (as the hash will just be truncated to the 32-bit boundary), but it will cause a panic in debug mode.

Replace (hash as usize) & self.mask with (hash & (self.mask as u64)) as usize to prevent overflow.

You may also want to change the type of self.mask to u64