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34 lines
726 B
34 lines
726 B
package rand
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import (
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"crypto/rand"
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"fmt"
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"io"
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"math/big"
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)
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func init() {
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Reader = rand.Reader
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}
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// Reader provides a random reader that can reset during testing.
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var Reader io.Reader
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var floatMaxBigInt = big.NewInt(1 << 53)
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// Float64 returns a float64 read from an io.Reader source. The returned float will be between [0.0, 1.0).
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func Float64(reader io.Reader) (float64, error) {
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bi, err := rand.Int(reader, floatMaxBigInt)
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if err != nil {
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return 0, fmt.Errorf("failed to read random value, %v", err)
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}
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return float64(bi.Int64()) / (1 << 53), nil
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}
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// CryptoRandFloat64 returns a random float64 obtained from the crypto rand
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// source.
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func CryptoRandFloat64() (float64, error) {
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return Float64(Reader)
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}
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