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#[cfg(all(feature = "enhanced-determinism", feature = "serde-serialize"))]
use indexmap::IndexMap as StdHashMap;
#[cfg(all(not(feature = "enhanced-determinism"), feature = "serde-serialize"))]
use std::collections::HashMap as StdHashMap;
#[cfg(feature = "serde-serialize")]
pub fn serialize_hashmap_capacity<S: serde::Serializer, K, V, H: std::hash::BuildHasher>(
map: &StdHashMap<K, V, H>,
s: S,
) -> Result<S::Ok, S::Error> {
s.serialize_u64(map.capacity() as u64)
}
#[cfg(feature = "serde-serialize")]
pub fn deserialize_hashmap_capacity<
'de,
D: serde::Deserializer<'de>,
K,
V,
H: std::hash::BuildHasher + Default,
>(
d: D,
) -> Result<StdHashMap<K, V, H>, D::Error> {
struct CapacityVisitor;
impl<'de> serde::de::Visitor<'de> for CapacityVisitor {
type Value = u64;
fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
write!(formatter, "an integer between 0 and 2^64")
}
fn visit_u64<E: serde::de::Error>(self, val: u64) -> Result<Self::Value, E> {
Ok(val)
}
}
let capacity = d.deserialize_u64(CapacityVisitor)? as usize;
Ok(StdHashMap::with_capacity_and_hasher(
capacity,
Default::default(),
))
}
#[cfg(feature = "enhanced-determinism")]
pub type FxHashMap32<K, V> = indexmap::IndexMap<K, V, std::hash::BuildHasherDefault<FxHasher32>>;
#[cfg(feature = "enhanced-determinism")]
pub use {self::FxHashMap32 as HashMap, indexmap::map::Entry};
#[cfg(not(feature = "enhanced-determinism"))]
pub use {rustc_hash::FxHashMap as HashMap, std::collections::hash_map::Entry};
const K: u32 = 0x9e3779b9;
pub struct FxHasher32 {
hash: u32,
}
impl Default for FxHasher32 {
#[inline]
fn default() -> FxHasher32 {
FxHasher32 { hash: 0 }
}
}
impl FxHasher32 {
#[inline]
fn add_to_hash(&mut self, i: u32) {
use std::ops::BitXor;
self.hash = self.hash.rotate_left(5).bitxor(i).wrapping_mul(K);
}
}
impl std::hash::Hasher for FxHasher32 {
#[inline]
fn write(&mut self, mut bytes: &[u8]) {
use std::convert::TryInto;
let read_u32 = |bytes: &[u8]| u32::from_ne_bytes(bytes[..4].try_into().unwrap());
let mut hash = FxHasher32 { hash: self.hash };
assert!(std::mem::size_of::<u32>() <= 8);
while bytes.len() >= std::mem::size_of::<u32>() {
hash.add_to_hash(read_u32(bytes) as u32);
bytes = &bytes[std::mem::size_of::<u32>()..];
}
if (std::mem::size_of::<u32>() > 4) && (bytes.len() >= 4) {
hash.add_to_hash(u32::from_ne_bytes(bytes[..4].try_into().unwrap()) as u32);
bytes = &bytes[4..];
}
if (std::mem::size_of::<u32>() > 2) && bytes.len() >= 2 {
hash.add_to_hash(u16::from_ne_bytes(bytes[..2].try_into().unwrap()) as u32);
bytes = &bytes[2..];
}
if (std::mem::size_of::<u32>() > 1) && bytes.len() >= 1 {
hash.add_to_hash(bytes[0] as u32);
}
self.hash = hash.hash;
}
#[inline]
fn write_u8(&mut self, i: u8) {
self.add_to_hash(i as u32);
}
#[inline]
fn write_u16(&mut self, i: u16) {
self.add_to_hash(i as u32);
}
#[inline]
fn write_u32(&mut self, i: u32) {
self.add_to_hash(i as u32);
}
#[inline]
fn write_u64(&mut self, i: u64) {
self.add_to_hash(i as u32);
self.add_to_hash((i >> 32) as u32);
}
#[inline]
fn write_usize(&mut self, i: usize) {
self.add_to_hash(i as u32);
}
#[inline]
fn finish(&self) -> u64 {
self.hash as u64
}
}