id和code的转换(Base62)

版本加密解密的实现

package lib

import (
    "fmt"
    "strconv"
)

func Id2Code(id int, version byte) string {
    var code string = ""
    if version == '1' {
        number := id
        for {
            remain := number % 10000000
            str := Base62Encode(remain)
            code = str + code
            number = number / 10000000
            if number == 0 {
                break
            }
        }
        code = string(version) + code
    }
    return code
}

func Code2Id(code string) int {
    version := code[0]
    code = code[1:]
    if version == '1' {
        var buffer string = ""
        for i := len(code); i > 0; i -= 4 {
            start := i - 4
            if start < 0 {
                start = 0
            }
            seg := code[start:i]
            segId := Base62Decode(seg)
            // 大于7位非法
            if segId >= 100000000 {
                return 0
            }
            buffer += fmt.Sprintf("%07d", Base62Decode(seg))
        }
        result, _ := strconv.Atoi(buffer)
        return result
    }
    return 0
}

Base62加密解密的实现

package lib

import (
    "math"
    "bytes"
)

const dictLength = 62

var dict []byte = []byte{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'}

func Base62Encode(id int) string {
    result := make([]byte, 0)
    number := id
    for number > 0 {
        round := number / dictLength
        remain := number % dictLength
        result = append([]byte{dict[remain]}, result...)
        number = round
    }
    return string(result)
}

func Base62Decode(code string) int {
    var result int = 0
    codeLength := len(code)
    for i, c := range []byte(code) {
        result += bytes.IndexByte(dict, c) * int(math.Pow(dictLength, float64(codeLength - 1 - i)))
    }
    return result
}