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|
use std::mem;
fn fmix64(mut k: u64) -> u64 {
k ^= k >> 33;
k = k.wrapping_mul(0xff51afd7ed558ccdu64);
k ^= k >> 33;
k = k.wrapping_mul(0xc4ceb9fe1a85ec53u64);
k ^= k >> 33;
return k;
}
fn get_128_block(bytes: &[u8], index: usize) -> (u64, u64) {
let b64: &[u64] = unsafe { mem::transmute(bytes) };
return (b64[index], b64[index + 1]);
}
pub fn murmurhash3_x64_128(bytes: &[u8], seed: u64) -> (u64, u64) {
let c1 = 0x87c37b91114253d5u64;
let c2 = 0x4cf5ad432745937fu64;
let read_size = 16;
let len = bytes.len() as u64;
let block_count = len / read_size;
let (mut h1, mut h2) = (seed, seed);
for i in 0..block_count as usize {
let (mut k1, mut k2) = get_128_block(bytes, i * 2);
k1 = k1.wrapping_mul(c1);
k1 = k1.rotate_left(31);
k1 = k1.wrapping_mul(c2);
h1 ^= k1;
h1 = h1.rotate_left(27);
h1 = h1.wrapping_add(h2);
h1 = h1.wrapping_mul(5);
h1 = h1.wrapping_add(0x52dce729);
k2 = k2.wrapping_mul(c2);
k2 = k2.rotate_left(33);
k2 = k2.wrapping_mul(c1);
h2 ^= k2;
h2 = h2.rotate_left(31);
h2 = h2.wrapping_add(h1);
h2 = h2.wrapping_mul(5);
h2 = h2.wrapping_add(0x38495ab5);
}
let (mut k1, mut k2) = (0u64, 0u64);
if len & 15 == 15 { k2 ^= (bytes[(block_count * read_size) as usize + 14] as u64) << 48; }
if len & 15 >= 14 { k2 ^= (bytes[(block_count * read_size) as usize + 13] as u64) << 40; }
if len & 15 >= 13 { k2 ^= (bytes[(block_count * read_size) as usize + 12] as u64) << 32; }
if len & 15 >= 12 { k2 ^= (bytes[(block_count * read_size) as usize + 11] as u64) << 24; }
if len & 15 >= 11 { k2 ^= (bytes[(block_count * read_size) as usize + 10] as u64) << 16; }
if len & 15 >= 10 { k2 ^= (bytes[(block_count * read_size) as usize + 9] as u64) << 8; }
if len & 15 >= 9 { k2 ^= bytes[(block_count * read_size) as usize + 8] as u64;
k2 = k2.wrapping_mul(c2);
k2 = k2.rotate_left(33);
k2 = k2.wrapping_mul(c1);
h2 ^= k2;
}
if len & 15 >= 8 { k1 ^= (bytes[(block_count * read_size) as usize + 7] as u64) << 56; }
if len & 15 >= 7 { k1 ^= (bytes[(block_count * read_size) as usize + 6] as u64) << 48; }
if len & 15 >= 6 { k1 ^= (bytes[(block_count * read_size) as usize + 5] as u64) << 40; }
if len & 15 >= 5 { k1 ^= (bytes[(block_count * read_size) as usize + 4] as u64) << 32; }
if len & 15 >= 4 { k1 ^= (bytes[(block_count * read_size) as usize + 3] as u64) << 24; }
if len & 15 >= 3 { k1 ^= (bytes[(block_count * read_size) as usize + 2] as u64) << 16; }
if len & 15 >= 2 { k1 ^= (bytes[(block_count * read_size) as usize + 1] as u64) << 8; }
if len & 15 >= 1 { k1 ^= bytes[(block_count * read_size) as usize + 0] as u64;
k1 = k1.wrapping_mul(c1);
k1 = k1.rotate_left(31);
k1 = k1.wrapping_mul(c2);
h1 ^= k1;
}
h1 ^= bytes.len() as u64;
h2 ^= bytes.len() as u64;
h1 = h1.wrapping_add(h2);
h2 = h2.wrapping_add(h1);
h1 = fmix64(h1);
h2 = fmix64(h2);
h1 = h1.wrapping_add(h2);
h2 = h2.wrapping_add(h1);
return (h1, h2);
}
#[cfg(test)]
mod test {
use super::murmurhash3_x64_128;
#[test]
fn test_empty_string() {
assert!(murmurhash3_x64_128("".as_bytes(), 0) == (0, 0));
}
#[test]
fn test_tail_lengths() {
assert!(murmurhash3_x64_128("1".as_bytes(), 0)
== (8213365047359667313, 10676604921780958775));
assert!(murmurhash3_x64_128("12".as_bytes(), 0)
== (5355690773644049813, 9855895140584599837));
assert!(murmurhash3_x64_128("123".as_bytes(), 0)
== (10978418110857903978, 4791445053355511657));
assert!(murmurhash3_x64_128("1234".as_bytes(), 0)
== (619023178690193332, 3755592904005385637));
assert!(murmurhash3_x64_128("12345".as_bytes(), 0)
== (2375712675693977547, 17382870096830835188));
assert!(murmurhash3_x64_128("123456".as_bytes(), 0)
== (16435832985690558678, 5882968373513761278));
assert!(murmurhash3_x64_128("1234567".as_bytes(), 0)
== (3232113351312417698, 4025181827808483669));
assert!(murmurhash3_x64_128("12345678".as_bytes(), 0)
== (4272337174398058908, 10464973996478965079));
assert!(murmurhash3_x64_128("123456789".as_bytes(), 0)
== (4360720697772133540, 11094893415607738629));
assert!(murmurhash3_x64_128("123456789a".as_bytes(), 0)
== (12594836289594257748, 2662019112679848245));
assert!(murmurhash3_x64_128("123456789ab".as_bytes(), 0)
== (6978636991469537545, 12243090730442643750));
assert!(murmurhash3_x64_128("123456789abc".as_bytes(), 0)
== (211890993682310078, 16480638721813329343));
assert!(murmurhash3_x64_128("123456789abcd".as_bytes(), 0)
== (12459781455342427559, 3193214493011213179));
assert!(murmurhash3_x64_128("123456789abcde".as_bytes(), 0)
== (12538342858731408721, 9820739847336455216));
assert!(murmurhash3_x64_128("123456789abcdef".as_bytes(), 0)
== (9165946068217512774, 2451472574052603025));
assert!(murmurhash3_x64_128("123456789abcdef1".as_bytes(), 0)
== (9259082041050667785, 12459473952842597282));
}
#[test]
fn test_large_data() {
assert!(murmurhash3_x64_128("Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam at consequat massa. Cras eleifend pellentesque ex, at dignissim libero maximus ut. Sed eget nulla felis".as_bytes(), 0)
== (9455322759164802692, 17863277201603478371));
}
#[cfg(feature="nightly")]
mod bench {
extern crate rand;
extern crate test;
use std::iter::FromIterator;
use self::rand::Rng;
use self::test::{Bencher, black_box};
use super::super::murmurhash3_x64_128;
fn run_bench(b: &mut Bencher, size: u64) {
let mut data: Vec<u8> = FromIterator::from_iter((0..size).map(|_| 0u8));
rand::thread_rng().fill_bytes(&mut data);
b.bytes = size;
b.iter(|| {
black_box(murmurhash3_x64_128(&data, 0));
});
}
#[bench]
fn bench_random_256k(b: &mut Bencher) {
run_bench(b, 256 * 1024);
}
#[bench]
fn bench_random_16b(b: &mut Bencher) {
run_bench(b, 16);
}
}
}
|
