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package random
import (
"crypto/md5" // #nosec G501 // Unly used to convert a string into a numer, no need for cryptographic safety
"fmt"
"math"
"math/rand"
"github.com/pkg/errors"
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"github.com/Luzifer/twitch-bot/v3/plugins"
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)
func Register ( args plugins . RegistrationArguments ) error {
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args . RegisterTemplateFunction ( "randomString" , plugins . GenericTemplateFunctionGetter ( randomString ) )
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args . RegisterTemplateFunction ( "seededRandom" , plugins . GenericTemplateFunctionGetter ( stableRandomFromSeed ) )
return nil
}
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func randomString ( lst ... string ) ( string , error ) {
if len ( lst ) == 0 {
return "" , errors . New ( "empty list given" )
}
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return lst [ rand . Intn ( len ( lst ) ) ] , nil // #nosec:G404 // This is used to select a random string from a list, no crypto-use
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}
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func stableRandomFromSeed ( seed string ) ( float64 , error ) {
seedValue , err := stringToSeed ( seed )
if err != nil {
return 0 , errors . Wrap ( err , "generating seed" )
}
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return rand . New ( rand . NewSource ( seedValue ) ) . Float64 ( ) , nil // #nosec:G404 // Only used for generating a random number from static string, no need for cryptographic safety
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}
func stringToSeed ( s string ) ( int64 , error ) {
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hash := md5 . New ( ) // #nosec:G401 // Unly used to convert a string into a numer, no need for cryptographic safety
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if _ , err := fmt . Fprint ( hash , s ) ; err != nil {
return 0 , errors . Wrap ( err , "writing string to hasher" )
}
var (
hashSum = hash . Sum ( nil )
sum int64
)
for i := 0 ; i < len ( hashSum ) ; i ++ {
sum += int64 ( float64 ( hashSum [ len ( hashSum ) - 1 - i ] % 10 ) * math . Pow ( 10 , float64 ( i ) ) ) //nolint:gomnd // No need to put the 10 of 10**i into a constant named "ten"
}
return sum , nil
}