github.com/872409/go-netease-im@v1.0.2-0.20201109080841-fdb3e13691c5/utils.go (about)

     1  package netease
     2  
     3  import (
     4  	"crypto/md5"
     5  	"crypto/sha1"
     6  	"encoding/hex"
     7  	"math/rand"
     8  	"strings"
     9  	"time"
    10  )
    11  
    12  const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
    13  const (
    14  	letterIdxBits = 6                    // 6 bits to represent a letter index
    15  	letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
    16  	letterIdxMax  = 63 / letterIdxBits   // # of letter indices fitting in 63 bits
    17  )
    18  
    19  var src = rand.NewSource(time.Now().UnixNano())
    20  
    21  func init() {
    22  	rand.Seed(time.Now().UTC().UnixNano())
    23  }
    24  
    25  // RandStringBytesMaskImprSrc .
    26  func RandStringBytesMaskImprSrc(n int) string {
    27  	b := make([]byte, n)
    28  	// A src.Int63() generates 63 random bits, enough for letterIdxMax characters!
    29  	for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; {
    30  		if remain == 0 {
    31  			cache, remain = src.Int63(), letterIdxMax
    32  		}
    33  		if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
    34  			b[i] = letterBytes[idx]
    35  			i--
    36  		}
    37  		cache >>= letterIdxBits
    38  		remain--
    39  	}
    40  
    41  	return string(b)
    42  }
    43  
    44  // RandNumber .
    45  func RandNumber(min, max int) int {
    46  	return min + rand.Intn(max-min)
    47  }
    48  
    49  // ShaHashToHexString SHA1加密字符串，并将加密结果转成16进制字符串
    50  func ShaHashToHexString(bv []byte) string {
    51  	hasher := sha1.New()
    52  	hasher.Write(bv)
    53  	return strings.ToLower(hex.EncodeToString(hasher.Sum(nil)))
    54  }
    55  
    56  // ShaHashToHexStringFromString .
    57  func ShaHashToHexStringFromString(src string) string {
    58  	return ShaHashToHexString([]byte(src))
    59  }
    60  
    61  // Md5HashToHexString .
    62  func Md5HashToHexString(bv []byte) string {
    63  	hasher := md5.New()
    64  	hasher.Write(bv)
    65  	return strings.ToLower(hex.EncodeToString(hasher.Sum(nil)))
    66  }