99 lines
2.5 KiB
Go
99 lines
2.5 KiB
Go
|
package hash64
|
|||
|
|
|
|||
|
|
/*
|
|||
|
|
* ***注意***
|
|||
|
|
*
|
|||
|
|
* Sum 使用的是[]byte参数；string中文是utf-8编码
|
|||
|
|
* SumByRune 使用的是[]rune参数；中文使用的是unicode编码
|
|||
|
|
*
|
|||
|
|
* 两种参数中文编码不同；同一个string调用两个接口得到的hash是不同的！！！ 这是要特别注意的
|
|||
|
|
*
|
|||
|
|
* 对string进行for range操作会自动被[]rune化；一定要注意！！！
|
|||
|
|
*
|
|||
|
|
*/
|
|||
|
|
|
|||
|
|
const shiftBit = 23 // 每个字节移位数(测试经验值23)
|
|||
|
|
const reverseBit = 64 - shiftBit
|
|||
|
|
|
|||
|
|
// 快速Hash计算(*** 注意：只取了rune低16位进行hash计算；计算结果与SumByRune不一致 ***)
|
|||
|
|
func FastSumByRune2(in rune, hs uint64) (out uint64) {
|
|||
|
|
out = ((hs << shiftBit) | (hs >> reverseBit)) + uint64(byte(in>>8))
|
|||
|
|
out = ((out << shiftBit) | (out >> reverseBit)) + uint64(byte(in))
|
|||
|
|
return
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// 快速Hash计算(*** 此计算结果与SumByRune一致 ***)
|
|||
|
|
func FastSumByRune4(in rune, hs uint64) (out uint64) {
|
|||
|
|
out = ((hs << shiftBit) | (hs >> reverseBit)) + uint64(byte(in>>24))
|
|||
|
|
out = ((out << shiftBit) | (out >> reverseBit)) + uint64(byte(in>>16))
|
|||
|
|
out = ((out << shiftBit) | (out >> reverseBit)) + uint64(byte(in>>8))
|
|||
|
|
out = ((out << shiftBit) | (out >> reverseBit)) + uint64(byte(in))
|
|||
|
|
return
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// 原Hash值参数重
|
|||
|
|
func hsArg(hsOpt ...uint64) (out uint64) {
|
|||
|
|
out = uint64(0)
|
|||
|
|
if len(hsOpt) > 0 {
|
|||
|
|
out = hsOpt[0]
|
|||
|
|
}
|
|||
|
|
return
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// Hash计算
|
|||
|
|
// in - 待hash串
|
|||
|
|
// hsOpt - 原hash值(在此基础上继续hash)
|
|||
|
|
func Sum(in []byte, hsOpt ...uint64) (out uint64) {
|
|||
|
|
out = hsArg(hsOpt...)
|
|||
|
|
for _, v := range in {
|
|||
|
|
out = ((out << shiftBit) | (out >> reverseBit)) + uint64(v)
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
return
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// Hash计算
|
|||
|
|
func SumByRune(in rune, hsOpt ...uint64) (out uint64) {
|
|||
|
|
// rune转[]byte
|
|||
|
|
inVal := make([]byte, 4)
|
|||
|
|
inVal[0] = byte(in >> 24)
|
|||
|
|
inVal[1] = byte(in >> 16)
|
|||
|
|
inVal[2] = byte(in >> 8)
|
|||
|
|
inVal[3] = byte(in)
|
|||
|
|
|
|||
|
|
// *** 经实际测试：不加以下代码运行效率更高 ***
|
|||
|
|
|
|||
|
|
// 去除前面多余的\x00
|
|||
|
|
// for {
|
|||
|
|
// if len(inVal) <= 1 {
|
|||
|
|
// // 以免全0异常；至少要保留1位
|
|||
|
|
// break
|
|||
|
|
// }
|
|||
|
|
// if inVal[0] == 0 {
|
|||
|
|
// inVal = inVal[1:]
|
|||
|
|
// } else {
|
|||
|
|
// break
|
|||
|
|
// }
|
|||
|
|
// }
|
|||
|
|
// 规避hash冲突，如："N-"与"中"unicode编码均为#4E2D，即会产生hash冲突
|
|||
|
|
// 若长度>1(即非常规ASCII)，所有字节最高位置1
|
|||
|
|
// if len(inVal) > 1 {
|
|||
|
|
// for i := 0; i < len(inVal); i++ {
|
|||
|
|
// inVal[i] |= 0x80
|
|||
|
|
// }
|
|||
|
|
// }
|
|||
|
|
out = Sum(inVal, hsOpt...)
|
|||
|
|
|
|||
|
|
return
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// Hash计算
|
|||
|
|
func SumByRunes(in []rune, hsOpt ...uint64) (out uint64) {
|
|||
|
|
out = hsArg(hsOpt...)
|
|||
|
|
for _, v := range in {
|
|||
|
|
out = SumByRune(v, out)
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
return
|
|||
|
|
}
|