GitHub Copilot
37 lines
770 B
Go
37 lines
770 B
Go
package webterm
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import (
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"crypto/rand"
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)
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const (
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identityAlphabet = "0123456789ABCDEFGHJKMNPQRSTUVWYZ"
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identitySize = 12
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)
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func GenerateID(size int) string {
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if size <= 0 {
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size = identitySize
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}
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const alphabetLen = len(identityAlphabet) // 31
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// Largest multiple of 31 that fits in a byte: 31*8 = 248
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const maxUnbiased = alphabetLen * (256 / alphabetLen) // 248
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out := make([]byte, size)
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buf := make([]byte, size+16) // extra bytes for rejection sampling
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filled := 0
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for filled < size {
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_, _ = rand.Read(buf)
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for _, b := range buf {
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if int(b) >= maxUnbiased {
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continue // reject to avoid modulo bias
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}
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out[filled] = identityAlphabet[int(b)%alphabetLen]
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filled++
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if filled >= size {
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break
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}
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}
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}
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return string(out)
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}
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