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package bloom
import "codeberg.org/lindenii/furgit/internal/intconv"
func murmur3SeededV2(seed uint32, data []byte) (uint32, error) {
const (
c1 = 0xcc9e2d51
c2 = 0x1b873593
r1 = 15
r2 = 13
m = 5
n = 0xe6546b64
)
h := seed
nblocks := len(data) / 4
for i := range nblocks {
k := uint32(data[4*i]) |
(uint32(data[4*i+1]) << 8) |
(uint32(data[4*i+2]) << 16) |
(uint32(data[4*i+3]) << 24)
k *= c1
k = (k << r1) | (k >> (32 - r1))
k *= c2
h ^= k
h = (h << r2) | (h >> (32 - r2))
h = h*m + n
}
var k1 uint32
tail := data[nblocks*4:]
switch len(tail) & 3 {
case 3:
k1 ^= uint32(tail[2]) << 16
fallthrough
case 2:
k1 ^= uint32(tail[1]) << 8
fallthrough
case 1:
k1 ^= uint32(tail[0])
k1 *= c1
k1 = (k1 << r1) | (k1 >> (32 - r1))
k1 *= c2
h ^= k1
}
dataLen, err := intconv.IntToUint32(len(data))
if err != nil {
return 0, err
}
h ^= dataLen
h ^= h >> 16
h *= 0x85ebca6b
h ^= h >> 13
h *= 0xc2b2ae35
h ^= h >> 16
return h, nil
}
func murmur3SeededV1(seed uint32, data []byte) (uint32, error) {
const (
c1 = 0xcc9e2d51
c2 = 0x1b873593
r1 = 15
r2 = 13
m = 5
n = 0xe6546b64
)
h := seed
nblocks := len(data) / 4
for i := range nblocks {
k := intconv.SignExtendByteToUint32(data[4*i]) |
(intconv.SignExtendByteToUint32(data[4*i+1]) << 8) |
(intconv.SignExtendByteToUint32(data[4*i+2]) << 16) |
(intconv.SignExtendByteToUint32(data[4*i+3]) << 24)
k *= c1
k = (k << r1) | (k >> (32 - r1))
k *= c2
h ^= k
h = (h << r2) | (h >> (32 - r2))
h = h*m + n
}
var k1 uint32
tail := data[nblocks*4:]
switch len(tail) & 3 {
case 3:
k1 ^= intconv.SignExtendByteToUint32(tail[2]) << 16
fallthrough
case 2:
k1 ^= intconv.SignExtendByteToUint32(tail[1]) << 8
fallthrough
case 1:
k1 ^= intconv.SignExtendByteToUint32(tail[0])
k1 *= c1
k1 = (k1 << r1) | (k1 >> (32 - r1))
k1 *= c2
h ^= k1
}
dataLen, err := intconv.IntToUint32(len(data))
if err != nil {
return 0, err
}
h ^= dataLen
h ^= h >> 16
h *= 0x85ebca6b
h ^= h >> 13
h *= 0xc2b2ae35
h ^= h >> 16
return h, nil
}
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