mc gen start

2026-07-05 10:25:43 +02:00
parent 201e0dfa44
commit a8b090227b
6 changed files with 433 additions and 0 deletions
@@ -0,0 +1,82 @@
+package gen
+
+import (
+	"crypto/md5"
+	"encoding/binary"
+)
+
+func rotl64(x uint64, b uint8) uint64 {
+	return (x << b) | (x >> (64 - b))
+}
+
+type Xoroshiro struct {
+	L uint64
+	H uint64
+}
+
+func (x *Xoroshiro) Next() uint64 {
+	l := x.L
+	h := x.H
+	n := rotl64(l+h, 17) + l
+	h ^= l
+	x.L = rotl64(l, 49) ^ h ^ (h << 21)
+	x.H = rotl64(h, 28)
+	return n
+}
+
+func (x *Xoroshiro) NextBound(n uint32) int32 {
+	r := (x.Next() & 0xFFFFFFFF) * uint64(n)
+	if uint32(r) < n {
+		for uint32(r) < (^n+1)%n {
+			r = (x.Next() & 0xFFFFFFFF) * uint64(n)
+		}
+	}
+	return int32(r >> 32)
+}
+
+func (x *Xoroshiro) NextFloat() float32 {
+	return float32(x.Next()>>(64-24)) * 5.9604645e-8
+}
+
+func (x *Xoroshiro) NextFloat64() float64 {
+	return float64(x.Next()>>(64-53)) * 1.1102230246251565e-16
+}
+
+func XoroshiroFromString(s string) (x Xoroshiro) {
+	sum := md5.Sum([]byte(s))
+	x.L = binary.BigEndian.Uint64(sum[:8])
+	x.H = binary.BigEndian.Uint64(sum[8:])
+	return
+}
+
+func XoroshiroFromSeed(seed int64) (x Xoroshiro) {
+	x.L = uint64(seed) ^ 0x6a09e667f3bcc909
+	x.H = x.L + 0x9e3779b97f4a7c15
+	return
+}
+
+func mixStafford13(s uint64) uint64 {
+	s = (s ^ (s >> 30)) * 0xbf58476d1ce4e5b9
+	s = (s ^ (s >> 27)) * 0x94d049bb133111eb
+	return s ^ (s >> 31)
+}
+
+func (x *Xoroshiro) Mix() {
+	x.L = mixStafford13(x.L)
+	x.H = mixStafford13(x.H)
+}
+
+func (x *Xoroshiro) Xor(x2 Xoroshiro) {
+	x.L ^= x2.L
+	x.H ^= x2.H
+}
+
+func (x *Xoroshiro) XorString(s string) {
+	x.Xor(XoroshiroFromString(s))
+}
+
+func (x *Xoroshiro) Split() (x2 Xoroshiro) {
+	x2.L = x.Next()
+	x2.H = x.Next()
+	return
+}