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// Package hash contains some common hash functions suitable for use in hash
// maps.
package hash
import "unsafe"
const DJBInit uint32 = 5381
func DJBCombine(acc, h uint32) uint32 {
return mul33(acc) + h
}
func DJB(hs ...uint32) uint32 {
acc := DJBInit
for _, h := range hs {
acc = DJBCombine(acc, h)
}
return acc
}
func UInt32(u uint32) uint32 {
return u
}
func UInt64(u uint64) uint32 {
return mul33(uint32(u>>32)) + uint32(u&0xffffffff)
}
func Pointer(p unsafe.Pointer) uint32 {
if unsafe.Sizeof(p) == 4 {
return UInt32(uint32(uintptr(p)))
} else {
return UInt64(uint64(uintptr(p)))
}
// NOTE: We don't care about 128-bit archs yet.
}
func UIntPtr(u uintptr) uint32 {
if unsafe.Sizeof(u) == 4 {
return UInt32(uint32(u))
} else {
return UInt64(uint64(u))
}
}
func String(s string) uint32 {
h := DJBInit
for i := 0; i < len(s); i++ {
h = DJBCombine(h, uint32(s[i]))
}
return h
}
func mul33(u uint32) uint32 {
return u<<5 + u
}
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