mirror of
https://github.com/charlienet/go-mixed.git
synced 2025-07-17 16:12:42 +08:00
108 lines
2.1 KiB
Go
108 lines
2.1 KiB
Go
package rand
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import (
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"crypto/rand"
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"io"
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_ "unsafe"
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"github.com/charlienet/go-mixed/bytesconv"
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)
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const (
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uppercase = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
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lowercase = "abcdefghijklmnopqrstuvwxyz"
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digit = "0123456789"
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nomix = "BCDFGHJKMPQRTVWXY2346789"
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letter = uppercase + lowercase
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allChars = uppercase + lowercase + digit
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hex = digit + "ABCDEF"
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_ = allChars + "/+"
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)
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var rng = NewFastRandGenerator() // NewRandGenerator()
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type charScope struct {
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bytes []byte
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length int
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max int
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bits int
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mask int
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}
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var (
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Uppercase = StringScope(uppercase) // 大写字母
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Lowercase = StringScope(lowercase) // 小写字母
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Digit = StringScope(digit) // 数字
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Nomix = StringScope(nomix) // 不混淆字符
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Letter = StringScope(letter) // 字母
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Hex = StringScope(hex) // 十六进制字符
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AllChars = StringScope(allChars) // 所有字符
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)
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func StringScope(str string) *charScope {
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len := len(str)
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scope := &charScope{
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bytes: bytesconv.StringToBytes(str),
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length: len,
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bits: 1,
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}
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for scope.mask < len {
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scope.bits++
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scope.mask = 1<<scope.bits - 1
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}
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scope.max = scope.mask / scope.bits
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return scope
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}
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// 生成指定长度的随机字符串
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func (scope *charScope) Generate(length int) string {
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n := length
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ret := make([]byte, n)
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for i, cache, remain := n-1, rng.Int63(), scope.max; i >= 0; {
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if remain == 0 {
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cache, remain = rng.Int63(), scope.max
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}
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if idx := int(cache & int64(scope.mask)); idx < scope.length {
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ret[i] = scope.bytes[idx]
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i--
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}
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cache >>= int64(scope.bits)
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remain--
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}
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return bytesconv.BytesToString(ret)
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}
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type scopeConstraint interface {
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~int | ~int32 | ~int64 | ~uint32
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}
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func Int[T scopeConstraint]() T {
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return T(rng.Int31())
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}
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// 生成区间 n >= 0, n < max
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func Intn[T scopeConstraint](max T) T {
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n := rng.Int63n(int64(max))
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return T(n) % max
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}
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// 生成区间 n >= min, n < max
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func IntRange[T scopeConstraint](min, max T) T {
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n := Intn(max - min)
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return T(n + min)
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}
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func RandBytes(len int) ([]byte, error) {
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r := make([]byte, len)
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_, err := io.ReadFull(rand.Reader, r)
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return r, err
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}
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