forked from TrueCloudLab/frostfs-node
5828f43e52
It is much more convenient to skip source creation. Also fix some bugs: 1. `cryptoSource.Int63()` now returns number in [0, 1<<63) as required by `rand.Source` interface. 2. Replace `cryptoSource.Uint63()` with `cryptoSource.Uint64` to allow generate uint64 numbers directly (see rand.Source64 docs). Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
44 lines
1,008 B
Go
44 lines
1,008 B
Go
package rand
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import (
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crand "crypto/rand"
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"encoding/binary"
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mrand "math/rand"
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)
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var source = mrand.New(&cryptoSource{})
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// Uint64 returns a random uint64 value.
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func Uint64() uint64 {
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return source.Uint64()
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}
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// Uint64 returns a random uint32 value.
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func Uint32() uint32 {
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return source.Uint32()
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}
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// Shuffle randomizes the order of elements.
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// n is the number of elements. Shuffle panics if n < 0.
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// swap swaps the elements with indexes i and j.
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func Shuffle(n int, swap func(i, j int)) {
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source.Shuffle(n, swap)
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}
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// cryptoSource is math/rand.Source which takes entropy via crypto/rand.
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type cryptoSource struct{}
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// Seed implements math/rand.Source.
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func (s *cryptoSource) Seed(int64) {}
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// Int63 implements math/rand.Source.
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func (s *cryptoSource) Int63() int64 {
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return int64(s.Uint64() >> 1)
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}
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// Uint64 implements math/rand.Source64.
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func (s *cryptoSource) Uint64() uint64 {
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var buf [8]byte
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_, _ = crand.Read(buf[:]) // always returns nil
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return binary.BigEndian.Uint64(buf[:])
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}
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