111 lines
2.4 KiB
JavaScript
111 lines
2.4 KiB
JavaScript
/*
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Modified for Node.js
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By shaffer
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*/
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/*
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https://github.com/esterTion/BiliBili_crc2mid
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*/
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var BiliBili_midcrc=function(){
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'use strict';
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const CRCPOLYNOMIAL = 0xEDB88320;
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var startTime=new Date().getTime(),
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crctable=new Array(256),
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create_table=function(){
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var crcreg,
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i,j;
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for (i = 0; i < 256; ++i)
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{
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crcreg = i;
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for (j = 0; j < 8; ++j)
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{
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if ((crcreg & 1) != 0)
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{
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crcreg = CRCPOLYNOMIAL ^ (crcreg >>> 1);
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}
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else
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{
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crcreg >>>= 1;
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}
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}
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crctable[i] = crcreg;
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}
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},
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crc32=function(input){
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if(typeof(input)!='string')
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input=input.toString();
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var crcstart = 0xFFFFFFFF, len = input.length, index;
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for(var i=0;i<len;++i){
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index = (crcstart ^ input.charCodeAt(i)) & 0xff;
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crcstart = (crcstart >>> 8) ^ crctable[index];
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}
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return crcstart;
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},
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crc32lastindex=function(input){
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if(typeof(input)!='string')
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input=input.toString();
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var crcstart = 0xFFFFFFFF, len = input.length, index;
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for(var i=0; i<len;++i){
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index = (crcstart ^ input.charCodeAt(i)) & 0xff;
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crcstart = (crcstart >>> 8) ^ crctable[index];
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}
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return index;
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},
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getcrcindex=function(t){
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//if(t>0)
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//t-=256;
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for(var i=0;i<256;i++){
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if(crctable[i] >>> 24 == t)
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return i;
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}
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return -1;
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},
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deepCheck=function(i, index){
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var tc=0x00,str='',
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hash=crc32(i);
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tc = hash & 0xff ^ index[2];
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if (!(tc <= 57 && tc >= 48))
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return [0];
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str+=tc-48;
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hash = crctable[index[2]] ^ (hash >>> 8);
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tc = hash & 0xff ^ index[1];
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if (!(tc <= 57 && tc >= 48))
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return [0];
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str+=tc-48;
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hash = crctable[index[1]] ^ (hash >>> 8);
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tc = hash & 0xff ^ index[0];
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if (!(tc <= 57 && tc >= 48))
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return [0];
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str+=tc-48;
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hash = crctable[index[0]] ^ (hash >>> 8);
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return [1,str];
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};
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create_table();
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var index=new Array(4);
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console.log('初始化耗时：'+(new Date().getTime()-startTime)+'ms');
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return function(input){
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var ht=parseInt('0x'+input)^0xffffffff,
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snum,i,lastindex,deepCheckData;
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for(i=3;i>=0;i--){
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index[3-i]=getcrcindex( ht >>> (i*8) );
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snum=crctable[index[3-i]];
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ht^=snum>>>((3-i)*8);
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}
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for(i=0;i<100000000; i++){
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lastindex = crc32lastindex(i);
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if(lastindex == index[3]){
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deepCheckData=deepCheck(i,index)
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if(deepCheckData[0])
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break;
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}
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}
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if(i==100000000)
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return -1;
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console.log('总耗时：'+(new Date().getTime()-startTime)+'ms');
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return i+''+deepCheckData[1];
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}
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}
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