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67 lines
1.2 KiB
67 lines
1.2 KiB
package mrand
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import (
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"math/rand"
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"sync"
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)
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// Everything in this file is taken from the math/rand package, which really
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// ought to expose lockedSource publicly.
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func read(p []byte, int63 func() int64, readVal *int64, readPos *int8) (n int, err error) {
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pos := *readPos
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val := *readVal
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for n = 0; n < len(p); n++ {
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if pos == 0 {
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val = int63()
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pos = 7
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}
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p[n] = byte(val)
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val >>= 8
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pos--
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}
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*readPos = pos
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*readVal = val
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return
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}
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type lockedSource struct {
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lk sync.Mutex
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src rand.Source64
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}
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func (r *lockedSource) Int63() (n int64) {
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r.lk.Lock()
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n = r.src.Int63()
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r.lk.Unlock()
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return
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}
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func (r *lockedSource) Uint64() (n uint64) {
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r.lk.Lock()
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n = r.src.Uint64()
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r.lk.Unlock()
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return
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}
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func (r *lockedSource) Seed(seed int64) {
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r.lk.Lock()
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r.src.Seed(seed)
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r.lk.Unlock()
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}
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// seedPos implements Seed for a lockedSource without a race condition.
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func (r *lockedSource) seedPos(seed int64, readPos *int8) {
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r.lk.Lock()
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r.src.Seed(seed)
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*readPos = 0
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r.lk.Unlock()
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}
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// read implements Read for a lockedSource without a race condition.
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func (r *lockedSource) read(p []byte, readVal *int64, readPos *int8) (n int, err error) {
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r.lk.Lock()
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n, err = read(p, r.src.Int63, readVal, readPos)
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r.lk.Unlock()
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return
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}
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