bilibili-API-collect/docs/misc/bvid_desc.md
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# bvid说明
2020-03-23 B站推出了全新的稿件视频id`bvid`来接替之前的`avid`,其意义与之相同
详见:
1. [【升级公告】AV号全面升级至BV号专栏](https://www.bilibili.com/read/cv5167957)
2. [【升级公告】AV号全面升级至BV号](https://www.bilibili.com/blackboard/activity-BV-PC.html)
## 概述
### 格式
“bvid”恒为长度为 12 的字符串,前 3 个固定为“BV1”后 9 个为 base58 计算结果(不包含数字 `0` 和大写字母 `I``O` 以及小写字母 `l`
### 实质
“bvid"为“avid”的base58编码可通过算法进行相互转化
### avid发号方式的变化
从 2009-09-09 09:09:09 [av2](https://www.bilibili.com/video/av2) 的发布到 2020-03-28 19:45:02 [av99999999](https://www.bilibili.com/video/av99999999) 的发布B站结束了以投稿时间为顺序的avid发放改为随机发放avid
~~暗示B站东方要完泪目~~
## 算法概述
~~算法以及程序主要参考[知乎@mcfx的回答](https://www.zhihu.com/question/381784377/answer/1099438784)~~
~~实际上该算法并不完整,新的算法参考自[【揭秘】av号转bv号的过程](https://www.bilibili.com/video/BV1N741127Tj)~~
实际上上面的算法依然不完整,新的算法参考自 [SocialSisterYi#740](https://github.com/SocialSisterYi/bilibili-API-collect/issues/740)~~来自 B 站某个 JS 文件?~~
### av->bv算法
**说明**
1. 目前的 BV 格式为 BV1XXXXXXXXX以 BV1 开头,后面包含 9 位有效数据。
2. AV 最大值为 2⁵¹。
**算法**
- 定义一个包含初始值为 `['B', 'V', '1', '0', '0', '0', '0', '0', '0', '0', '0', '0']` 的长度为 12 的数组`bytes`,用于存储转换后的字符。
- 定义变量 `bv_idx` 并初始化为数组 `bytes` 的最后一个索引。
- 将输入的 `aid` 与 avid 最大值2⁵¹进行按位或运算其结果与常量 `XOR_CODE`23442827791579进行异或运算得到变量 `tmp`
-`tmp` 大于0时循环执行以下操作直到小于0
-`tmp` 除以 58码表的长度 的余数作为索引,从 `FcwAPNKTMug3GV5Lj7EJnHpWsx4tb8haYeviqBz6rkCy12mUSDQX9RdoZf` 码表中取出对应的字符,并将其赋值给 `bytes[bv_idx]`
-`tmp` 与 58 求模赋值给 `tmp`
-`bv_idx` 减1。
-`bytes` 数组中索引为 3 和 9 的元素进行交换。
-`bytes` 数组中索引为 4 和 7 的元素进行交换。
-`bytes` 数组转换为字符串,并返回结果。
### bv->av算法
#av->bv算法 的逆向
-`bvid` 中索引为 3 和 9 的字符进行交换。
-`bvid` 中索引为 4 和 7 的字符进行交换。
- 删除 `bvid` 前3个字符固定为 BV1
- 定义变量 `tmp` 并初始化为 0。
- 遍历 `bvid` 的每个字符,执行以下操作:
- 获取当前字符在 `FcwAPNKTMug3GV5Lj7EJnHpWsx4tb8haYeviqBz6rkCy12mUSDQX9RdoZf` 码表中的索引,并将其赋值给变量 `idx`
-`tmp` 乘以常量 58并加上 `idx`,最后赋值给 `tmp`
-`tmp` 与常量 2⁵¹ - 1 进行按位与运算,其结果与常量 `XOR_CODE`23442827791579 进行异或运算,得到最终结果。
## 编程实现
### JavaScript/TypeScript
<CodeGroup>
<CodeGroupItem title="JavaScript">
```javascript
const XOR_CODE = 23442827791579n;
const MASK_CODE = 2251799813685247n;
const MAX_AID = 1n << 51n;
const BASE = 58n;
const data = 'FcwAPNKTMug3GV5Lj7EJnHpWsx4tb8haYeviqBz6rkCy12mUSDQX9RdoZf';
function av2bv(aid) {
const bytes = ['B', 'V', '1', '0', '0', '0', '0', '0', '0', '0', '0', '0'];
let bvIndex = bytes.length - 1;
let tmp = (MAX_AID | BigInt(aid)) ^ XOR_CODE;
while (tmp > 0) {
bytes[bvIndex] = data[Number(tmp % BigInt(BASE))];
tmp = tmp / BASE;
bvIndex -= 1;
}
[bytes[3], bytes[9]] = [bytes[9], bytes[3]];
[bytes[4], bytes[7]] = [bytes[7], bytes[4]];
return bytes.join('');
}
function bv2av(bvid) {
const bvidArr = Array.from(bvid);
[bvidArr[3], bvidArr[9]] = [bvidArr[9], bvidArr[3]];
[bvidArr[4], bvidArr[7]] = [bvidArr[7], bvidArr[4]];
bvidArr.splice(0, 3);
const tmp = bvidArr.reduce((pre, bvidChar) => pre * BASE + BigInt(data.indexOf(bvidChar)), 0n);
return Number((tmp & MASK_CODE) ^ XOR_CODE);
}
console.log(av2bv(111298867365120));
console.log(bv2av('BV1L9Uoa9EUx'));
```
</CodeGroupItem>
<CodeGroupItem title="TypeScript">
```typescript
const XOR_CODE = 23442827791579n;
const MASK_CODE = 2251799813685247n;
const MAX_AID = 1n << 51n;
const BASE = 58n;
const data = 'FcwAPNKTMug3GV5Lj7EJnHpWsx4tb8haYeviqBz6rkCy12mUSDQX9RdoZf';
function av2bv(aid: number) {
const bytes = ['B', 'V', '1', '0', '0', '0', '0', '0', '0', '0', '0', '0'];
let bvIndex = bytes.length - 1;
let tmp = (MAX_AID | BigInt(aid)) ^ XOR_CODE;
while (tmp > 0) {
bytes[bvIndex] = data[Number(tmp % BigInt(BASE))];
tmp = tmp / BASE;
bvIndex -= 1;
}
[bytes[3], bytes[9]] = [bytes[9], bytes[3]];
[bytes[4], bytes[7]] = [bytes[7], bytes[4]];
return bytes.join('') as `BV1${string}`;
}
function bv2av(bvid: `BV1${string}`) {
const bvidArr = Array.from<string>(bvid);
[bvidArr[3], bvidArr[9]] = [bvidArr[9], bvidArr[3]];
[bvidArr[4], bvidArr[7]] = [bvidArr[7], bvidArr[4]];
bvidArr.splice(0, 3);
const tmp = bvidArr.reduce((pre, bvidChar) => pre * BASE + BigInt(data.indexOf(bvidChar)), 0n);
return Number((tmp & MASK_CODE) ^ XOR_CODE);
}
console.log(av2bv(111298867365120));
console.log(bv2av('BV1L9Uoa9EUx'));
```
</CodeGroupItem>
</CodeGroup>
### Python
来自:[#847](https://github.com/SocialSisterYi/bilibili-API-collect/issues/847#issuecomment-1807020675)
```python
XOR_CODE = 23442827791579
MASK_CODE = 2251799813685247
MAX_AID = 1 << 51
ALPHABET = "FcwAPNKTMug3GV5Lj7EJnHpWsx4tb8haYeviqBz6rkCy12mUSDQX9RdoZf"
ENCODE_MAP = 8, 7, 0, 5, 1, 3, 2, 4, 6
DECODE_MAP = tuple(reversed(ENCODE_MAP))
BASE = len(ALPHABET)
PREFIX = "BV1"
PREFIX_LEN = len(PREFIX)
CODE_LEN = len(ENCODE_MAP)
def av2bv(aid: int) -> str:
bvid = [""] * 9
tmp = (MAX_AID | aid) ^ XOR_CODE
for i in range(CODE_LEN):
bvid[ENCODE_MAP[i]] = ALPHABET[tmp % BASE]
tmp //= BASE
return PREFIX + "".join(bvid)
def bv2av(bvid: str) -> int:
assert bvid[:3] == PREFIX
bvid = bvid[3:]
tmp = 0
for i in range(CODE_LEN):
idx = ALPHABET.index(bvid[DECODE_MAP[i]])
tmp = tmp * BASE + idx
return (tmp & MASK_CODE) ^ XOR_CODE
assert av2bv(111298867365120) == "BV1L9Uoa9EUx"
assert bv2av("BV1L9Uoa9EUx") == 111298867365120
```
### Rust
参考 <https://github.com/Colerar/abv/blob/main/src/lib.rs>
### Swift
```swift
fileprivate let XOR_CODE: UInt64 = 23442827791579
fileprivate let MASK_CODE: UInt64 = 2251799813685247
fileprivate let MAX_AID: UInt64 = 1 << 51
fileprivate let data: [UInt8] = [70, 99, 119, 65, 80, 78, 75, 84, 77, 117, 103, 51, 71, 86, 53, 76, 106, 55, 69, 74, 110, 72, 112, 87, 115, 120, 52, 116, 98, 56, 104, 97, 89, 101, 118, 105, 113, 66, 122, 54, 114, 107, 67, 121, 49, 50, 109, 85, 83, 68, 81, 88, 57, 82, 100, 111, 90, 102]
fileprivate let BASE: UInt64 = 58
fileprivate let BV_LEN: Int = 12
fileprivate let PREFIX: String = "BV1"
func av2bv(avid: UInt64) -> String {
var bytes: [UInt8] = [66, 86, 49, 48, 48, 48, 48, 48, 48, 48, 48, 48]
var bvIdx = BV_LEN - 1
var tmp = (MAX_AID | avid) ^ XOR_CODE
while tmp != 0 {
bytes[bvIdx] = data[Int(tmp % BASE)]
tmp /= BASE
bvIdx -= 1
}
bytes.swapAt(3, 9)
bytes.swapAt(4, 7)
return String(decoding: bytes, as: UTF8.self)
}
func bv2av(bvid: String) -> UInt64 {
let fixedBvid: String
if bvid.hasPrefix("BV") {
fixedBvid = bvid
} else {
fixedBvid = "BV" + bvid
}
var bvidArray = Array(fixedBvid.utf8)
bvidArray.swapAt(3, 9)
bvidArray.swapAt(4, 7)
let trimmedBvid = String(decoding: bvidArray[3...], as: UTF8.self)
var tmp: UInt64 = 0
for char in trimmedBvid {
if let idx = data.firstIndex(of: char.utf8.first!) {
tmp = tmp * BASE + UInt64(idx)
}
}
return (tmp & MASK_CODE) ^ XOR_CODE
}
print(av2bv(avid: 111298867365120))
print(bv2av(bvid: "BV1L9Uoa9EUx"))
```
### Java
```java
import java.math.BigInteger;
/**
* @author cctyl
*/
public class AVBVConverter {
private static final BigInteger XOR_CODE = BigInteger.valueOf(23442827791579L);
private static final BigInteger MASK_CODE = BigInteger.valueOf(2251799813685247L);
private static final BigInteger MAX_AID = BigInteger.ONE.shiftLeft(51);
private static final int BASE = 58;
private static final String DATA = "FcwAPNKTMug3GV5Lj7EJnHpWsx4tb8haYeviqBz6rkCy12mUSDQX9RdoZf";
public static String av2bv(long aidParam) {
BigInteger aid = BigInteger.valueOf(aidParam);
char[] bytes = {'B', 'V', '1', '0', '0', '0', '0', '0', '0', '0', '0', '0'};
int bvIndex = bytes.length - 1;
BigInteger tmp = MAX_AID.or(aid).xor(XOR_CODE);
while (tmp.compareTo(BigInteger.ZERO) > 0) {
bytes[bvIndex] = DATA.charAt(tmp.mod(BigInteger.valueOf(BASE)).intValue());
tmp = tmp.divide(BigInteger.valueOf(BASE));
bvIndex--;
}
swap(bytes, 3, 9);
swap(bytes, 4, 7);
return new String(bytes);
}
public static long bv2av(String bvid) {
char[] bvidArr = bvid.toCharArray();
swap(bvidArr, 3, 9);
swap(bvidArr, 4, 7);
String adjustedBvid = new String(bvidArr, 3, bvidArr.length - 3);
BigInteger tmp = BigInteger.ZERO;
for (char c : adjustedBvid.toCharArray()) {
tmp = tmp.multiply(BigInteger.valueOf(BASE)).add(BigInteger.valueOf(DATA.indexOf(c)));
}
BigInteger xor = tmp.and(MASK_CODE).xor(XOR_CODE);
return xor.longValue();
}
private static void swap(char[] array, int i, int j) {
char temp = array[i];
array[i] = array[j];
array[j] = temp;
}
public static void main(String[] args) {
final int aid1 = 643755790;
final String bv1 = "BV1bY4y1j7RA";
final int aid2 = 305988942;
final String bv2 = "BV1aP411K7it";
//av ==> bv
assert av2bv(aid1).equals(bv1);
assert av2bv(aid2).equals(bv2);
//bv ==>av
assert bv2av(bv1) == aid1;
assert bv2av(bv2) == aid2;
}
}
```
### Golang
```go
package main
import (
"fmt"
"strings"
)
var (
XOR_CODE = int64(23442827791579)
MAX_CODE = int64(2251799813685247)
CHARTS = "FcwAPNKTMug3GV5Lj7EJnHpWsx4tb8haYeviqBz6rkCy12mUSDQX9RdoZf"
PAUL_NUM = int64(58)
)
func swapString(s string, x, y int) string {
chars := []rune(s)
chars[x], chars[y] = chars[y], chars[x]
return string(chars)
}
func Bvid2Avid(bvid string) (avid int64) {
s := swapString(swapString(bvid, 3, 9), 4, 7)
bv1 := string([]rune(s)[3:])
temp := int64(0)
for _, c := range bv1 {
idx := strings.IndexRune(CHARTS, c)
temp = temp*PAUL_NUM + int64(idx)
}
avid = (temp & MAX_CODE) ^ XOR_CODE
return
}
func Avid2Bvid(avid int64) (bvid string) {
arr := [12]string{"B", "V", "1"}
bvIdx := len(arr) - 1
temp := (avid | (MAX_CODE + 1)) ^ XOR_CODE
for temp > 0 {
idx := temp % PAUL_NUM
arr[bvIdx] = string(CHARTS[idx])
temp /= PAUL_NUM
bvIdx--
}
raw := strings.Join(arr[:], "")
bvid = swapString(swapString(raw, 3, 9), 4, 7)
return
}
func main() {
avid := int64(1054803170)
bvid := "BV1mH4y1u7UA"
resAvid := Bvid2Avid(bvid)
resBvid := Avid2Bvid(avid)
fmt.Printf("convert bvid to avid: %v\tvalue:%v\n", avid == resAvid, resAvid)
fmt.Printf("convert avid to bvid: %v\tvalue:%v\n", bvid == resBvid, resBvid)
}
```
### C++
```cpp
#include <algorithm>
#include <cassert>
#include <print>
#include <string>
constexpr int64_t XOR_CODE = 0x1552356C4CDB;
constexpr int64_t MAX_AID = 0x8000000000000;
constexpr int64_t MASK_CODE = MAX_AID - 1;
constexpr int64_t BASE = 58;
constexpr char Table[BASE + 1] = "FcwAPNKTMug3GV5Lj7EJnHpWsx4tb8haYeviqBz6rkCy12mUSDQX9RdoZf";
constexpr char ReverseTable[128] = {
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x2c, 0x2d, 0x0b, 0x1a, 0x0e, 0x27, 0x11, 0x1d, 0x34, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x03, 0x25, 0x2a, 0x31, 0x12, 0x00, 0x0c, 0x15, 0x00, 0x13, 0x06, 0x0f, 0x08, 0x05, 0x00,
0x04, 0x32, 0x35, 0x30, 0x07, 0x2f, 0x0d, 0x17, 0x33, 0x20, 0x38, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x1f, 0x1c, 0x01, 0x36, 0x21, 0x39, 0x0a, 0x1e, 0x23, 0x10, 0x29, 0x00, 0x2e, 0x14, 0x37,
0x16, 0x24, 0x28, 0x18, 0x1b, 0x09, 0x22, 0x02, 0x19, 0x2b, 0x26, 0x00, 0x00, 0x00, 0x00, 0x00
};
std::string Av2bv(const int64_t Avid) {
assert(Avid > 0 && "Avid must be greater than 0");
std::string bv = "BV1";
bv.resize(12, '\0');
int64_t tmp = (Avid | MAX_AID) ^ XOR_CODE;
for (size_t i = bv.size() - 1; tmp > 0 && i > 2; --i) {
bv[i] = Table[tmp % BASE];
tmp /= BASE;
}
std::ranges::swap(bv.at(3), bv.at(9));
std::ranges::swap(bv.at(4), bv.at(7));
return bv;
}
int64_t Bv2av(const std::string &Bvid) {
assert(Bvid.starts_with("BV1") && "Bvid must start with 'BV1'");
auto Bvid_ = Bvid;
std::ranges::swap(Bvid_.at(3), Bvid_.at(9));
std::ranges::swap(Bvid_.at(4), Bvid_.at(7));
int64_t tmp = 0;
for (int i = 3; i < Bvid_.size(); ++i) {
tmp = ReverseTable[Bvid_.at(i)] + BASE * tmp;
}
return (tmp & MASK_CODE) ^ XOR_CODE;
}
int main() {
assert(Av2bv(1004871019) == "BV16x4y1H7M1");
assert(Bv2av("BV16x4y1H7M1") == 1004871019);
}
```
## 老版算法存档
**以下算法已失效**,编解码函数值域有限,不推荐使用,在此仅作为存档
<details>
<summary>查看折叠内容:</summary>
算法参考自[【揭秘】av号转bv号的过程](https://www.bilibili.com/video/BV1N741127Tj)
### av->bv算法
注:本算法及示例程序仅能编解码`avid < 29460791296`且暂无法验证`avid >= 29460791296`的正确性
再注:本人不清楚新算法能否编解码`avid >= 29460791296`
1. a = (avid ⊕ 177451812) + 100618342136696320
2. 以 i 为循环变量循环 6 次 b[i] = (a / 58 ^ i) % 58
3. 将 b[i] 中各个数字转换为以下码表中的字符
码表:
> fZodR9XQDSUm21yCkr6zBqiveYah8bt4xsWpHnJE7jL5VG3guMTKNPAwcF
4. 初始化字符串 b[i]=` `
5. 按照以下字符顺序编码表编码并填充至 b[i]
字符顺序编码表:
> 0 -> 9
>
> 1 -> 8
>
> 2 -> 1
>
> 3 -> 6
>
> 4 -> 2
>
> 5 -> 4
>
> 6 -> 0
>
> 7 -> 7
>
> 8 -> 3
>
> 9 -> 5
### bv->av算法
为以上算法的逆运算
### 编程实现
使用 Python C TypeScript Java Kotlin Golang Rust 等语言作为示例,欢迎社区提交更多例程
#### Python
```python
XOR = 177451812
ADD = 100618342136696320
TABLE = "fZodR9XQDSUm21yCkr6zBqiveYah8bt4xsWpHnJE7jL5VG3guMTKNPAwcF"
MAP = 9, 8, 1, 6, 2, 4, 0, 7, 3, 5
def av2bv(av: int) -> str:
av = (av ^ XOR) + ADD
bv = [""] * 10
for i in range(10):
bv[MAP[i]] = TABLE[(av // 58**i) % 58]
return "".join(bv)
def bv2av(bv: int) -> int:
av = [""] * 10
s = 0
for i in range(10):
s += TABLE.find(bv[MAP[i]]) * 58**i
av = (s - ADD) ^ XOR
return av
def main():
while 1:
mode = input("1. AV to BV\n2. BV to AV\n3. Exit\n你的选择:")
if mode == "1":
print(f"BV号是BV {av2bv(int(input('AV号是')))}")
elif mode == "2":
print(f"AV号是AV {bv2av(input('BV号是'))}")
elif mode == "3":
break
else:
print("输入错误请重新输入")
if __name__ == "__main__":
main()
```
#### C
```c
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
const char table[] = "fZodR9XQDSUm21yCkr6zBqiveYah8bt4xsWpHnJE7jL5VG3guMTKNPAwcF"; // 码表
char tr[124]; // 反查码表
const unsigned long long XOR = 177451812; // 固定异或值
const unsigned long long ADD = 8728348608; // 固定加法值
const int s[] = {11, 10, 3, 8, 4, 6}; // 位置编码表
// 初始化反查码表
void tr_init() {
for (int i = 0; i < 58; i++)
tr[table[i]] = i;
}
unsigned long long bv2av(char bv[]) {
unsigned long long r = 0;
unsigned long long av;
for (int i = 0; i < 6; i++)
r += tr[bv[s[i]]] * (unsigned long long)pow(58, i);
av = (r - ADD) ^ XOR;
return av;
}
char *av2bv(unsigned long long av) {
char *result = (char*)malloc(13);
strcpy(result,"BV1 4 1 7 ");
av = (av ^ XOR) + ADD;
for (int i = 0; i < 6; i++)
result[s[i]] = table[(unsigned long long)(av / (unsigned long long)pow(58, i)) % 58];
return result;
}
int main() {
tr_init();
printf("%s\n", av2bv(170001));
printf("%u\n", bv2av("BV17x411w7KC"));
return 0;
}
```
输出为:
```
BV17x411w7KC
170001
```
#### TypeScript
感谢[#417](https://github.com/SocialSisterYi/bilibili-API-collect/issues/417#issuecomment-1186475063)提供
```typescript
export default class BvCode {
private TABEL = 'fZodR9XQDSUm21yCkr6zBqiveYah8bt4xsWpHnJE7jL5VG3guMTKNPAwcF'; // 码表
private TR: Record<string, number> = {}; // 反查码表
private S = [11, 10, 3, 8, 4, 6]; // 位置编码表
private XOR = 177451812; // 固定异或值
private ADD = 8728348608; // 固定加法值
constructor() {
// 初始化反查码表
const len = this.TABEL.length;
for (let i = 0; i < len; i++) {
this.TR[this.TABEL[i]] = i;
}
}
av2bv(av: number): string {
const x_ = (av ^ this.XOR) + this.ADD;
const r = ['B', 'V', '1', , , '4', , '1', , '7'];
for (let i = 0; i < 6; i++) {
r[this.S[i]] = this.TABEL[Math.floor(x_ / 58 ** i) % 58];
}
return r.join('');
}
bv2av(bv: string): number {
let r = 0;
for (let i = 0; i < 6; i++) {
r += this.TR[bv[this.S[i]]] * 58 ** i;
}
return (r - this.ADD) ^ this.XOR;
}
}
const bvcode = new BvCode();
console.log(bvcode.av2bv(170001));
console.log(bvcode.bv2av('BV17x411w7KC'));
```
输出为:
```
BV17x411w7KC
170001
```
#### Java
```java
/**
* 算法来自https://www.zhihu.com/question/381784377/answer/1099438784
*/
public class Util {
private static final String TABLE = "fZodR9XQDSUm21yCkr6zBqiveYah8bt4xsWpHnJE7jL5VG3guMTKNPAwcF";
private static final int[] S = new int[]{11, 10, 3, 8, 4, 6};
private static final int XOR = 177451812;
private static final long ADD = 8728348608L;
private static final Map<Character, Integer> MAP = new HashMap<>();
static {
for (int i = 0; i < 58; i++) {
MAP.put(TABLE.charAt(i), i);
}
}
public static String aidToBvid(int aid) {
long x = (aid ^ XOR) + ADD;
char[] chars = new char[]{'B', 'V', '1', ' ', ' ', '4', ' ', '1', ' ', '7', ' ', ' '};
for (int i = 0; i < 6; i++) {
int pow = (int) Math.pow(58, i);
long i1 = x / pow;
int index = (int) (i1 % 58);
chars[S[i]] = TABLE.charAt(index);
}
return String.valueOf(chars);
}
public static int bvidToAid(String bvid) {
long r = 0;
for (int i = 0; i < 6; i++) {
r += MAP.get(bvid.charAt(S[i])) * Math.pow(58, i);
}
return (int) ((r - ADD) ^ XOR);
}
}
```
#### Kotlin
```kotlin
/**
* 此程序非完全原创改编自GH站内某大佬的Java程序修改了部分代码且转换为Kotlin
* 算法来源同上
*/
object VideoUtils {
//这里是由知乎大佬不知道用什么方法得出的转换用数字
var ss = intArrayOf(11, 10, 3, 8, 4, 6, 2, 9, 5, 7)
var xor: Long = 177451812 //二进制时加减数1
var add = 8728348608L //十进制时加减数2
//变量初始化工作,加载哈希表
private const val table = "fZodR9XQDSUm21yCkr6zBqiveYah8bt4xsWpHnJE7jL5VG3guMTKNPAwcF"
private val mp = HashMap<String, Int>()
private val mp2 = HashMap<Int, String>()
//现在定义av号和bv号互转的方法
//定义一个power乘方方法这是转换进制必要的
fun power(a: Int, b: Int): Long {
var power: Long = 1
for (c in 0 until b) power *= a.toLong()
return power
}
//bv转av方法
fun bv2av(s: String): String {
var r: Long = 0
//58进制转换
for (i in 0..57) {
val s1 = table.substring(i, i + 1)
mp[s1] = i
}
for (i in 0..5) {
r += mp[s.substring(ss[i], ss[i] + 1)]!! * power(58, i)
}
//转换完成后,需要处理,带上两个随机数
return (r - add xor xor).toString()
}
//av转bv方法
fun av2bv(st: String): String {
try {
var s = java.lang.Long.valueOf(st.split("av".toRegex()).dropLastWhile { it.isEmpty() }
.toTypedArray()[1])
val sb = StringBuffer("BV1 4 1 7 ")
//逆向思路,先将随机数还原
s = (s xor xor) + add
//58进制转回
for (i in 0..57) {
val s1 = table.substring(i, i + 1)
mp2[i] = s1
}
for (i in 0..5) {
val r = mp2[(s / power(58, i) % 58).toInt()]
sb.replace(ss[i], ss[i] + 1, r!!)
}
return sb.toString()
} catch (e: ArrayIndexOutOfBoundsException) {
return ""
}
}
}
```
#### Golang
```go
package main
import "math"
const TABLE = "fZodR9XQDSUm21yCkr6zBqiveYah8bt4xsWpHnJE7jL5VG3guMTKNPAwcF"
var S = [11]uint{11, 10, 3, 8, 4, 6}
const XOR = 177451812
const ADD = 8728348608
var TR = map[string]int64{}
// 初始化 TR
func init() {
for i := 0; i < 58; i++ {
TR[TABLE[i:i+1]] = int64(i)
}
}
func BV2AV(bv string) int64 {
r := int64(0)
for i := 0; i < 6; i++ {
r += TR[bv[S[i]:S[i]+1]] * int64(math.Pow(58, float64(i)))
}
return (r - ADD) ^ XOR
}
func AV2BV(av int64) string {
x := (av ^ XOR) + ADD
r := []rune("BV1 4 1 7 ")
for i := 0; i < 6; i++ {
r[S[i]] = rune(TABLE[x/int64(math.Pow(58, float64(i)))%58])
}
return string(r)
}
func main() {
println(AV2BV(170001))
println(BV2AV("BV17x411w7KC"))
}
```
输出为:
```
BV17x411w7KC
170001
```
#### Rust
crate: https://github.com/stackinspector/bvid
```rust
// Copyright (c) 2023 stackinspector. MIT license.
const XORN: u64 = 177451812;
const ADDN: u64 = 100618342136696320;
const TABLE: [u8; 58] = *b"fZodR9XQDSUm21yCkr6zBqiveYah8bt4xsWpHnJE7jL5VG3guMTKNPAwcF";
const MAP: [usize; 10] = [9, 8, 1, 6, 2, 4, 0, 7, 3, 5];
const REV_TABLE: [u8; 74] = [
13, 12, 46, 31, 43, 18, 40, 28, 5, 0, 0, 0, 0, 0, 0, 0, 54, 20, 15, 8,
39, 57, 45, 36, 0, 38, 51, 42, 49, 52, 0, 53, 7, 4, 9, 50, 10, 44, 34, 6,
25, 1, 0, 0, 0, 0, 0, 0, 26, 29, 56, 3, 24, 0, 47, 27, 22, 41, 16, 0,
11, 37, 2, 35, 21, 17, 33, 30, 48, 23, 55, 32, 14, 19,
];
const POW58: [u64; 10] = [
1, 58, 3364, 195112, 11316496, 656356768, 38068692544,
2207984167552, 128063081718016, 7427658739644928,
];
fn av2bv(avid: u64) -> [u8; 10] {
let a = (avid ^ XORN) + ADDN;
let mut bvid = [0; 10];
for i in 0..10 {
bvid[MAP[i]] = TABLE[(a / POW58[i]) as usize % 58];
}
bvid
}
fn bv2av(bvid: [u8; 10]) -> u64 {
let mut a = 0;
for i in 0..10 {
a += REV_TABLE[bvid[MAP[i]] as usize - 49] as u64 * POW58[i];
}
(a - ADDN) ^ XORN
}
// assert_eq!(*b"17x411w7KC", av2bv(170001));
// assert_eq!(170001, bv2av(*b"17x411w7KC"));
```
</details>