137 lines
3.6 KiB
Go
137 lines
3.6 KiB
Go
package random
|
|
|
|
import (
|
|
"crypto/rand"
|
|
"fmt"
|
|
"io"
|
|
"math/big"
|
|
)
|
|
|
|
// Cryptographical is the production random.Provider which uses crypto/rand.
|
|
type Cryptographical struct{}
|
|
|
|
// Read implements the io.Reader interface.
|
|
func (r *Cryptographical) Read(p []byte) (n int, err error) {
|
|
return io.ReadFull(rand.Reader, p)
|
|
}
|
|
|
|
// BytesErr returns random data as bytes with the standard random.DefaultN length and can contain any byte values
|
|
// (including unreadable byte values). If an error is returned from the random read this function returns it.
|
|
func (r *Cryptographical) BytesErr() (data []byte, err error) {
|
|
data = make([]byte, DefaultN)
|
|
|
|
_, err = rand.Read(data)
|
|
|
|
return data, err
|
|
}
|
|
|
|
// Bytes returns random data as bytes with the standard random.DefaultN length and can contain any byte values
|
|
// (including unreadable byte values). If an error is returned from the random read this function ignores it.
|
|
func (r *Cryptographical) Bytes() (data []byte) {
|
|
data, _ = r.BytesErr()
|
|
|
|
return data
|
|
}
|
|
|
|
// BytesCustomErr returns random data as bytes with n length and can contain only byte values from the provided
|
|
// values. If n is less than 1 then DefaultN is used instead. If an error is returned from the random read this function
|
|
// returns it.
|
|
func (r *Cryptographical) BytesCustomErr(n int, charset []byte) (data []byte, err error) {
|
|
if n < 1 {
|
|
n = DefaultN
|
|
}
|
|
|
|
data = make([]byte, n)
|
|
|
|
if _, err = rand.Read(data); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
t := len(charset)
|
|
|
|
for i := 0; i < n; i++ {
|
|
data[i] = charset[data[i]%byte(t)]
|
|
}
|
|
|
|
return data, nil
|
|
}
|
|
|
|
// StringCustomErr is an overload of BytesCustomWithErr which takes a characters string and returns a string.
|
|
func (r *Cryptographical) StringCustomErr(n int, characters string) (data string, err error) {
|
|
var d []byte
|
|
|
|
if d, err = r.BytesCustomErr(n, []byte(characters)); err != nil {
|
|
return "", err
|
|
}
|
|
|
|
return string(d), nil
|
|
}
|
|
|
|
// BytesCustom returns random data as bytes with n length and can contain only byte values from the provided values.
|
|
// If n is less than 1 then DefaultN is used instead. If an error is returned from the random read this function
|
|
// ignores it.
|
|
func (r *Cryptographical) BytesCustom(n int, charset []byte) (data []byte) {
|
|
data, _ = r.BytesCustomErr(n, charset)
|
|
|
|
return data
|
|
}
|
|
|
|
// StringCustom is an overload of BytesCustom which takes a characters string and returns a string.
|
|
func (r *Cryptographical) StringCustom(n int, characters string) (data string) {
|
|
return string(r.BytesCustom(n, []byte(characters)))
|
|
}
|
|
|
|
// IntErr returns a random *big.Int error combination with a maximum of max.
|
|
func (r *Cryptographical) IntErr(max *big.Int) (value *big.Int, err error) {
|
|
if max == nil {
|
|
return nil, fmt.Errorf("max is required")
|
|
}
|
|
|
|
if max.Sign() <= 0 {
|
|
return nil, fmt.Errorf("max must be 1 or more")
|
|
}
|
|
|
|
return rand.Int(rand.Reader, max)
|
|
}
|
|
|
|
// Int returns a random *big.Int with a maximum of max.
|
|
func (r *Cryptographical) Int(max *big.Int) (value *big.Int) {
|
|
var err error
|
|
|
|
if value, err = r.IntErr(max); err != nil {
|
|
return big.NewInt(-1)
|
|
}
|
|
|
|
return value
|
|
}
|
|
|
|
// IntegerErr returns a random int error combination with a maximum of n.
|
|
func (r *Cryptographical) IntegerErr(n int) (value int, err error) {
|
|
if n <= 0 {
|
|
return 0, fmt.Errorf("n must be more than 0")
|
|
}
|
|
|
|
max := big.NewInt(int64(n))
|
|
|
|
var result *big.Int
|
|
|
|
if result, err = r.IntErr(max); err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
value = int(result.Int64())
|
|
|
|
if value < 0 {
|
|
return 0, fmt.Errorf("generated number is too big for int")
|
|
}
|
|
|
|
return value, nil
|
|
}
|
|
|
|
// Integer returns a random int with a maximum of n.
|
|
func (r *Cryptographical) Integer(n int) (value int) {
|
|
value, _ = r.IntegerErr(n)
|
|
|
|
return value
|
|
}
|