37 lines
915 B
Go
37 lines
915 B
Go
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package entropy
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import (
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"fmt"
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"github.com/hashicorp/errwrap"
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)
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type Sourcer interface {
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GetRandom(bytes int) ([]byte, error)
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}
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type Reader struct {
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source Sourcer
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}
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func NewReader(source Sourcer) *Reader{
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return &Reader{source}
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}
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// Read reads exactly len(p) bytes from r into p.
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// If r returns an error having read at least len(p) bytes, the error is dropped.
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// It returns the number of bytes copied and an error if fewer bytes were read.
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// On return, n == len(p) if and only if err == nil.
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func (r *Reader) Read(p []byte) (n int, err error){
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requested := len(p)
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randBytes, err := r.source.GetRandom(requested)
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delivered := copy(p, randBytes)
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if delivered != requested {
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if err != nil {
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return delivered, errwrap.Wrapf("unable to fill provided buffer with entropy: {{err}}", err)
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}
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return delivered, fmt.Errorf("unable to fill provided buffer with entropy")
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}
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return delivered, nil
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}
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