字節字符串到JavaScript中的字節數組（節點）

Question

我正在嘗試使用JS和Node完成pythonchallenge，並且目前陷入挑戰8，我需要使用bzip2解壓縮此字符串：

BZh91AY&SYA\xaf\x82\r\x00\x00\x01\x01\x80\x02\xc0\x02\x00 \x00!\x9ah3M\x07<]\xc9\x14\xe1BA\x06\xbe\x084

我正在嘗試使用compressjs庫並遵循以下方法：

var x = new Buffer(byteSting, "utf8");
    var decompressed = bz2.decompressFile(x);

而且我不斷收到錯誤：

TypeError: Data error: initial position out of bounds

我看了這里提供的解決方案： https : //the-python-challenge-solutions.hackingnote.com/level-8.html但是我不知道如何在python中執行與b'相同的操作。

這讓我發瘋，如果有人可以幫助我，我將不勝感激！

Answer 1

var byteArray = new Uint8Array(your_response)您的響應arrayBuffer

比

var data = bzip2.simple(bzip2.array(byteArray));

使用bzip2.js

var bzip2={};bzip2.array=function(bytes){var bit=0,byte=0;var BITMASK=[0,0x01,0x03,0x07,0x0F,0x1F,0x3F,0x7F,0xFF];return function(n){var result=0;while(n>0){var left=8-bit;if(n>=left){result<<=left;result|=(BITMASK[left]&bytes[byte++]);bit=0;n-=left;}else{result<<=n;result|=((bytes[byte]&(BITMASK[n]<<(8-n-bit)))>>(8-n-bit));bit+=n;n=0;}}
return result}}
bzip2.simple=function(bits){var size=bzip2.header(bits);var all='',chunk='';do{all+=chunk;chunk=bzip2.decompress(bits,size);}while(chunk!=-1);return all;}
bzip2.header=function(bits){if(bits(8*3)!=4348520)throw"No magic number found";var i=bits(8)-48;if(i<1||i>9)throw"Not a BZIP archive";return i;};bzip2.decompress=function(bits,size,len){var MAX_HUFCODE_BITS=20;var MAX_SYMBOLS=258;var SYMBOL_RUNA=0;var SYMBOL_RUNB=1;var GROUP_SIZE=50;var bufsize=100000*size;for(var h='',i=0;i<6;i++)h+=bits(8).toString(16);if(h=="177245385090")return-1;if(h!="314159265359")throw"eek not valid bzip data";bits(32);if(bits(1))throw"unsupported obsolete version";var origPtr=bits(24);if(origPtr>bufsize)throw"Initial position larger than buffer size";var t=bits(16);var symToByte=new Uint8Array(256),symTotal=0;for(i=0;i<16;i++){if(t&(1<<(15-i))){var k=bits(16);for(j=0;j<16;j++){if(k&(1<<(15-j))){symToByte[symTotal++]=(16*i)+j;}}}}
var groupCount=bits(3);if(groupCount<2||groupCount>6)throw"another error";var nSelectors=bits(15);if(nSelectors==0)throw"meh";var mtfSymbol=[];for(var i=0;i<groupCount;i++)mtfSymbol[i]=i;var selectors=new Uint8Array(32768);for(var i=0;i<nSelectors;i++){for(var j=0;bits(1);j++)if(j>=groupCount)throw"whoops another error";var uc=mtfSymbol[j];mtfSymbol.splice(j,1);mtfSymbol.splice(0,0,uc);selectors[i]=uc;}
var symCount=symTotal+2;var groups=[];for(var j=0;j<groupCount;j++){var length=new Uint8Array(MAX_SYMBOLS),temp=new Uint8Array(MAX_HUFCODE_BITS+1);t=bits(5);for(var i=0;i<symCount;i++){while(true){if(t<1||t>MAX_HUFCODE_BITS)throw"I gave up a while ago on writing error messages";if(!bits(1))break;if(!bits(1))t++;else t--;}
length[i]=t;}
var minLen,maxLen;minLen=maxLen=length[0];for(var i=1;i<symCount;i++){if(length[i]>maxLen)maxLen=length[i];else if(length[i]<minLen)minLen=length[i];}
var hufGroup;hufGroup=groups[j]={};hufGroup.permute=new Uint32Array(MAX_SYMBOLS);hufGroup.limit=new Uint32Array(MAX_HUFCODE_BITS+1);hufGroup.base=new Uint32Array(MAX_HUFCODE_BITS+1);hufGroup.minLen=minLen;hufGroup.maxLen=maxLen;var base=hufGroup.base.subarray(1);var limit=hufGroup.limit.subarray(1);var pp=0;for(var i=minLen;i<=maxLen;i++)
for(var t=0;t<symCount;t++)
if(length[t]==i)hufGroup.permute[pp++]=t;for(i=minLen;i<=maxLen;i++)temp[i]=limit[i]=0;for(i=0;i<symCount;i++)temp[length[i]]++;pp=t=0;for(i=minLen;i<maxLen;i++){pp+=temp[i];limit[i]=pp-1;pp<<=1;base[i+1]=pp-(t+=temp[i]);}
limit[maxLen]=pp+temp[maxLen]-1;base[minLen]=0;}
var byteCount=new Uint32Array(256);for(var i=0;i<256;i++)mtfSymbol[i]=i;var runPos,count,symCount,selector;runPos=count=symCount=selector=0;var buf=new Uint32Array(bufsize);while(true){if(!(symCount--)){symCount=GROUP_SIZE-1;if(selector>=nSelectors)throw"meow i'm a kitty, that's an error";hufGroup=groups[selectors[selector++]];base=hufGroup.base.subarray(1);limit=hufGroup.limit.subarray(1);}
i=hufGroup.minLen;j=bits(i);while(true){if(i>hufGroup.maxLen)throw"rawr i'm a dinosaur";if(j<=limit[i])break;i++;j=(j<<1)|bits(1);}
j-=base[i];if(j<0||j>=MAX_SYMBOLS)throw"moo i'm a cow";var nextSym=hufGroup.permute[j];if(nextSym==SYMBOL_RUNA||nextSym==SYMBOL_RUNB){if(!runPos){runPos=1;t=0;}
if(nextSym==SYMBOL_RUNA)t+=runPos;else t+=2*runPos;runPos<<=1;continue;}
if(runPos){runPos=0;if(count+t>=bufsize)throw"Boom.";uc=symToByte[mtfSymbol[0]];byteCount[uc]+=t;while(t--)buf[count++]=uc;}
if(nextSym>symTotal)break;if(count>=bufsize)throw"I can't think of anything. Error";i=nextSym-1;uc=mtfSymbol[i];mtfSymbol.splice(i,1);mtfSymbol.splice(0,0,uc);uc=symToByte[uc];byteCount[uc]++;buf[count++]=uc;}
if(origPtr<0||origPtr>=count)throw"I'm a monkey and I'm throwing something at someone, namely you";var j=0;for(var i=0;i<256;i++){k=j+byteCount[i];byteCount[i]=j;j=k;}
for(var i=0;i<count;i++){uc=buf[i]&0xff;buf[byteCount[uc]]|=(i<<8);byteCount[uc]++;}
var pos=0,current=0,run=0;if(count){pos=buf[origPtr];current=(pos&0xff);pos>>=8;run=-1;}
count=count;var output='';var copies,previous,outbyte;if(!len)len=Infinity;while(count){count--;previous=current;pos=buf[pos];current=pos&0xff;pos>>=8;if(run++==3){copies=current;outbyte=previous;current=-1;}else{copies=1;outbyte=current;}
while(copies--){output+=(String.fromCharCode(outbyte));if(!--len)return output;}
if(current!=previous)run=0;}
return output;}