/
math.go
116 lines (103 loc) · 2.66 KB
/
math.go
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package utils
import (
"bytes"
"fmt"
"math"
"math/rand"
"time"
"unsafe"
)
// 浮点数除法
func Div(n, b float64) float64 {
return math.Log(n) / math.Log(b)
}
// PowInt is int type of math.Pow function.
func PowInt(x int, y int) int {
if y <= 0 {
return 1
} else {
if y%2 == 0 {
sqrt := PowInt(x, y/2)
return sqrt * sqrt
} else {
return PowInt(x, y-1) * x
}
}
}
func RandInt(start int, end int) int {
// 范围检查
if end < start {
return 0
}
// 随机数生成器,加入时间戳保证每次生成的随机数不一样
r := rand.New(rand.NewSource(time.Now().UnixNano()))
// 生成随机数
return r.Intn(end-start) + start
}
func RandInt64(start int64, end int64) int64 {
// 范围检查
if end < start {
return 0
}
// 随机数生成器,加入时间戳保证每次生成的随机数不一样
r := rand.New(rand.NewSource(time.Now().UnixNano()))
// 生成随机数
return r.Int63n(end-start) + start
}
// 生成六位随机码
func GenerateRandomCode() string {
rnd := rand.New(rand.NewSource(time.Now().UnixNano()))
code := fmt.Sprintf("%06v", rnd.Int31n(1000000))
return code
}
// 指定长度随机中文字符(包含复杂字符)
func GenFixedLengthChineseChars(length int) string {
var buf bytes.Buffer
for i := 0; i < length; i++ {
buf.WriteRune(rune(RandInt(19968, 40869)))
}
return buf.String()
}
// 指定范围随机中文字符
func GenRandomLengthChineseChars(start, end int) string {
length := RandInt(start, end)
return GenFixedLengthChineseChars(length)
}
// 随机英文小写字母
func RandStr(len int) string {
rand.Seed(time.Now().UnixNano())
data := make([]byte, len)
for i := 0; i < len; i++ {
data[i] = byte(rand.Intn(26) + 97)
}
return string(data)
}
/**
* 生成指定长度的随机字母和数字字符串,包括0-9、a-z、A-Z的所有字符。
*
* @param length
* @return
*/
func RandString(n int) string {
b := make([]byte, n)
// A src.Int63() generates 63 random bits, enough for letterIdxMax characters!
for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; {
if remain == 0 {
cache, remain = src.Int63(), letterIdxMax
}
if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
b[i] = letterBytes[idx]
i--
}
cache >>= letterIdxBits
remain--
}
return *(*string)(unsafe.Pointer(&b))
}
var src = rand.NewSource(time.Now().UnixNano())
const letterBytes = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
const (
letterIdxBits = 6 // 6 bits to represent a letter index
letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
letterIdxMax = 63 / letterIdxBits // # of letter indices fitting in 63 bits
)