DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Mercurial (81f420f057e4)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278
#![doc(html_root_url = "https://docs.rs/phf_shared/0.7")]
#![cfg_attr(not(feature = "std"), no_std)]

#[cfg(feature = "std")]
extern crate std as core;

extern crate siphasher;

#[cfg(feature = "unicase")]
extern crate unicase;

use core::fmt;
use core::hash::{Hasher, Hash};
use core::num::Wrapping;
use siphasher::sip128::{Hash128, Hasher128, SipHasher13};

pub struct Hashes {
    pub g: u32,
    pub f1: u32,
    pub f2: u32,
    _priv: (),
}

/// A central typedef for hash keys
///
/// Makes experimentation easier by only needing to be updated here.
pub type HashKey = u64;

#[inline]
pub fn displace(f1: u32, f2: u32, d1: u32, d2: u32) -> u32 {
    (Wrapping(d2) + Wrapping(f1) * Wrapping(d1) + Wrapping(f2)).0
}

/// `key` is from `phf_generator::HashState`.
#[inline]
pub fn hash<T: ?Sized + PhfHash>(x: &T, key: &HashKey) -> Hashes {
    let mut hasher = SipHasher13::new_with_keys(0, *key);
    x.phf_hash(&mut hasher);

    let Hash128 { h1: lower, h2: upper} = hasher.finish128();

    Hashes {
        g: (lower >> 32) as u32,
        f1: lower as u32,
        f2: upper as u32,
        _priv: (),
    }
}

/// Return an index into `phf_generator::HashState::map`.
///
/// * `hash` is from `hash()` in this crate.
/// * `disps` is from `phf_generator::HashState::disps`.
/// * `len` is the length of `phf_generator::HashState::map`.
#[inline]
pub fn get_index(hashes: &Hashes, disps: &[(u32, u32)], len: usize) -> u32 {
    let (d1, d2) = disps[(hashes.g % (disps.len() as u32)) as usize];
    displace(hashes.f1, hashes.f2, d1, d2) % (len as u32)
}

/// A trait implemented by types which can be used in PHF data structures.
///
/// This differs from the standard library's `Hash` trait in that `PhfHash`'s
/// results must be architecture independent so that hashes will be consistent
/// between the host and target when cross compiling.
pub trait PhfHash {
    /// Feeds the value into the state given, updating the hasher as necessary.
    fn phf_hash<H: Hasher>(&self, state: &mut H);

    /// Feeds a slice of this type into the state provided.
    fn phf_hash_slice<H: Hasher>(data: &[Self], state: &mut H)
        where Self: Sized
    {
        for piece in data {
            piece.phf_hash(state);
        }
    }
}

/// Trait for printing types with `const` constructors, used by `phf_codegen` and `phf_macros`.
pub trait FmtConst {
    /// Print a `const` expression representing this value.
    fn fmt_const(&self, f: &mut fmt::Formatter) -> fmt::Result;
}

/// Create an impl of `FmtConst` delegating to `fmt::Debug` for types that can deal with it.
///
/// Ideally with specialization this could be just one default impl and then specialized where
/// it doesn't apply.
macro_rules! delegate_debug (
    ($ty:ty) => {
        impl FmtConst for $ty {
            fn fmt_const(&self, f: &mut fmt::Formatter) -> fmt::Result {
                write!(f, "{:?}", self)
            }
        }
    }
);

delegate_debug!(str);
delegate_debug!(char);
delegate_debug!(u8);
delegate_debug!(i8);
delegate_debug!(u16);
delegate_debug!(i16);
delegate_debug!(u32);
delegate_debug!(i32);
delegate_debug!(u64);
delegate_debug!(i64);
delegate_debug!(u128);
delegate_debug!(i128);
delegate_debug!(bool);

#[cfg(feature = "std")]
impl PhfHash for String {
    #[inline]
    fn phf_hash<H: Hasher>(&self, state: &mut H) {
        (**self).phf_hash(state)
    }
}

#[cfg(feature = "std")]
impl PhfHash for Vec<u8> {
    #[inline]
    fn phf_hash<H: Hasher>(&self, state: &mut H) {
        (**self).phf_hash(state)
    }
}

impl<'a, T: 'a + PhfHash + ?Sized> PhfHash for &'a T {
    fn phf_hash<H: Hasher>(&self, state: &mut H) {
        (*self).phf_hash(state)
    }
}

impl<'a, T: 'a + FmtConst + ?Sized> FmtConst for &'a T {
    fn fmt_const(&self, f: &mut fmt::Formatter) -> fmt::Result {
        (*self).fmt_const(f)
    }
}

impl PhfHash for str {
    #[inline]
    fn phf_hash<H: Hasher>(&self, state: &mut H) {
        self.as_bytes().phf_hash(state)
    }
}

impl PhfHash for [u8] {
    #[inline]
    fn phf_hash<H: Hasher>(&self, state: &mut H) {
        state.write(self);
    }
}

impl FmtConst for [u8] {
    #[inline]
    fn fmt_const(&self, f: &mut fmt::Formatter) -> fmt::Result {
        // slices need a leading reference
        write!(f, "&{:?}", self)
    }
}

#[cfg(feature = "unicase")]
impl<S> PhfHash for unicase::UniCase<S>
    where unicase::UniCase<S>: Hash {
    #[inline]
    fn phf_hash<H: Hasher>(&self, state: &mut H) {
        self.hash(state)
    }
}

#[cfg(feature = "unicase")]
impl<S> FmtConst for unicase::UniCase<S> where S: AsRef<str> {
    fn fmt_const(&self, f: &mut fmt::Formatter) -> fmt::Result {
        if self.is_ascii() {
            f.write_str("UniCase::ascii(")?;
        } else {
            f.write_str("UniCase::unicode(")?;
        }

        self.as_ref().fmt_const(f)?;
        f.write_str(")")
    }
}

macro_rules! sip_impl (
    (le $t:ty) => (
        impl PhfHash for $t {
            #[inline]
            fn phf_hash<H: Hasher>(&self, state: &mut H) {
                self.to_le().hash(state);
            }
        }
    );
    ($t:ty) => (
        impl PhfHash for $t {
            #[inline]
            fn phf_hash<H: Hasher>(&self, state: &mut H) {
                self.hash(state);
            }
        }
    )
);

sip_impl!(u8);
sip_impl!(i8);
sip_impl!(le u16);
sip_impl!(le i16);
sip_impl!(le u32);
sip_impl!(le i32);
sip_impl!(le u64);
sip_impl!(le i64);
sip_impl!(le u128);
sip_impl!(le i128);
sip_impl!(bool);

impl PhfHash for char {
    #[inline]
    fn phf_hash<H: Hasher>(&self, state: &mut H) {
        (*self as u32).phf_hash(state)
    }
}

// minimize duplicated code since formatting drags in quite a bit
fn fmt_array(array: &[u8], f: &mut fmt::Formatter) -> fmt::Result {
    write!(f, "{:?}", array)
}

macro_rules! array_impl (
    ($t:ty, $n:expr) => (
        impl PhfHash for [$t; $n] {
            #[inline]
            fn phf_hash<H: Hasher>(&self, state: &mut H) {
                state.write(self);
            }
        }

        impl FmtConst for [$t; $n] {
            fn fmt_const(&self, f: &mut fmt::Formatter) -> fmt::Result {
                fmt_array(self, f)
            }
        }
    )
);

array_impl!(u8, 1);
array_impl!(u8, 2);
array_impl!(u8, 3);
array_impl!(u8, 4);
array_impl!(u8, 5);
array_impl!(u8, 6);
array_impl!(u8, 7);
array_impl!(u8, 8);
array_impl!(u8, 9);
array_impl!(u8, 10);
array_impl!(u8, 11);
array_impl!(u8, 12);
array_impl!(u8, 13);
array_impl!(u8, 14);
array_impl!(u8, 15);
array_impl!(u8, 16);
array_impl!(u8, 17);
array_impl!(u8, 18);
array_impl!(u8, 19);
array_impl!(u8, 20);
array_impl!(u8, 21);
array_impl!(u8, 22);
array_impl!(u8, 23);
array_impl!(u8, 24);
array_impl!(u8, 25);
array_impl!(u8, 26);
array_impl!(u8, 27);
array_impl!(u8, 28);
array_impl!(u8, 29);
array_impl!(u8, 30);
array_impl!(u8, 31);
array_impl!(u8, 32);