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Fix murmur64a's tail handling.

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Also, split up the murmur64 proc into murmur64a and murmur64b as they're distinct hashes with their own output.
This commit is contained in:
Jeroen van Rijn
2022-07-15 13:02:07 +02:00
parent 157c87b2a2
commit 3e6ec65dd9
1 changed files with 101 additions and 95 deletions
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core/hash/hash.odin
+101 -95
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@@ -172,108 +172,114 @@ murmur32 :: proc(data: []byte, seed := u32(0)) -> u32 {
return h1 return h1
} }
// See https://github.com/aappleby/smhasher/blob/master/src/MurmurHash2.cpp#L96
@(optimization_mode="speed") @(optimization_mode="speed")
murmur64 :: proc(data: []byte, seed := u64(0x9747b28c)) -> u64 { murmur64a :: proc(data: []byte, seed := u64(0x9747b28c)) -> u64 {
when size_of(int) == 8 { m :: 0xc6a4a7935bd1e995
m :: 0xc6a4a7935bd1e995 r :: 47
r :: 47
h: u64 = seed ~ (u64(len(data)) * m) h: u64 = seed ~ (u64(len(data)) * m)
data64 := mem.slice_ptr(cast(^u64)raw_data(data), len(data)/size_of(u64)) data64 := mem.slice_data_cast([]u64, data)
for _, i in data64 { for _, i in data64 {
k := data64[i] k := data64[i]
k *= m k *= m
k ~= k>>r k ~= k>>r
k *= m k *= m
h ~= k h ~= k
h *= m
}
switch len(data)&7 {
case 7: h ~= u64(data[6]) << 48; fallthrough
case 6: h ~= u64(data[5]) << 40; fallthrough
case 5: h ~= u64(data[4]) << 32; fallthrough
case 4: h ~= u64(data[3]) << 24; fallthrough
case 3: h ~= u64(data[2]) << 16; fallthrough
case 2: h ~= u64(data[1]) << 8; fallthrough
case 1:
h ~= u64(data[0])
h *= m
}
h ~= h>>r
h *= m h *= m
h ~= h>>r
return h
} else {
m :: 0x5bd1e995
r :: 24
h1 := u32(seed) ~ u32(len(data))
h2 := u32(seed) >> 32
data32 := mem.slice_ptr(cast(^u32)raw_data(data), len(data)/size_of(u32))
len := len(data)
i := 0
for len >= 8 {
k1, k2: u32
k1 = data32[i]; i += 1
k1 *= m
k1 ~= k1>>r
k1 *= m
h1 *= m
h1 ~= k1
len -= 4
k2 = data32[i]; i += 1
k2 *= m
k2 ~= k2>>r
k2 *= m
h2 *= m
h2 ~= k2
len -= 4
}
if len >= 4 {
k1: u32
k1 = data32[i]; i += 1
k1 *= m
k1 ~= k1>>r
k1 *= m
h1 *= m
h1 ~= k1
len -= 4
}
// TODO(bill): Fix this
#no_bounds_check data8 := mem.slice_to_bytes(data32[i:])[:3]
switch len {
case 3:
h2 ~= u32(data8[2]) << 16
fallthrough
case 2:
h2 ~= u32(data8[1]) << 8
fallthrough
case 1:
h2 ~= u32(data8[0])
h2 *= m
}
h1 ~= h2>>18
h1 *= m
h2 ~= h1>>22
h2 *= m
h1 ~= h2>>17
h1 *= m
h2 ~= h1>>19
h2 *= m
return u64(h1)<<32 | u64(h2)
} }
offset := len(data64) * size_of(u64)
switch len(data)&7 {
case 7: h ~= u64(data[offset + 6]) << 48; fallthrough
case 6: h ~= u64(data[offset + 5]) << 40; fallthrough
case 5: h ~= u64(data[offset + 4]) << 32; fallthrough
case 4: h ~= u64(data[offset + 3]) << 24; fallthrough
case 3: h ~= u64(data[offset + 2]) << 16; fallthrough
case 2: h ~= u64(data[offset + 1]) << 8; fallthrough
case 1:
h ~= u64(data[offset + 0])
h *= m
}
h ~= h>>r
h *= m
h ~= h>>r
return h
}
// See https://github.com/aappleby/smhasher/blob/master/src/MurmurHash2.cpp#L140
@(optimization_mode="speed")
murmur64b :: proc(data: []byte, seed := u64(0x9747b28c)) -> u64 {
m :: 0x5bd1e995
r :: 24
h1 := u32(seed) ~ u32(len(data))
h2 := u32(seed) >> 32
data32 := mem.slice_ptr(cast(^u32)raw_data(data), len(data)/size_of(u32))
len := len(data)
i := 0
for len >= 8 {
k1, k2: u32
k1 = data32[i]; i += 1
k1 *= m
k1 ~= k1>>r
k1 *= m
h1 *= m
h1 ~= k1
len -= 4
k2 = data32[i]; i += 1
k2 *= m
k2 ~= k2>>r
k2 *= m
h2 *= m
h2 ~= k2
len -= 4
}
if len >= 4 {
k1: u32
k1 = data32[i]; i += 1
k1 *= m
k1 ~= k1>>r
k1 *= m
h1 *= m
h1 ~= k1
len -= 4
}
// TODO(bill): Fix this
#no_bounds_check data8 := mem.slice_to_bytes(data32[i:])[:3]
switch len {
case 3:
h2 ~= u32(data8[2]) << 16
fallthrough
case 2:
h2 ~= u32(data8[1]) << 8
fallthrough
case 1:
h2 ~= u32(data8[0])
h2 *= m
}
h1 ~= h2>>18
h1 *= m
h2 ~= h1>>22
h2 *= m
h1 ~= h2>>17
h1 *= m
h2 ~= h1>>19
h2 *= m
return u64(h1)<<32 | u64(h2)
} }
@(optimization_mode="speed") @(optimization_mode="speed")