38 lines
1.8 KiB
JavaScript
38 lines
1.8 KiB
JavaScript
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'use strict';
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// MD5 is required by Baidu's upload protocol; it is not used for authentication.
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const ZhaoFileHash=(()=>{
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const shifts=[7,12,17,22,5,9,14,20,4,11,16,23,6,10,15,21];
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const constants=Array.from({length:64},(_,i)=>Math.floor(Math.abs(Math.sin(i+1))*4294967296)|0);
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function md5(input){
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const bytes=new Uint8Array(input),length=bytes.length,padded=new Uint8Array(Math.ceil((length+9)/64)*64);
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padded.set(bytes);padded[length]=128;const view=new DataView(padded.buffer);
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view.setUint32(padded.length-8,(length*8)>>>0,true);view.setUint32(padded.length-4,Math.floor(length/536870912),true);
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let h=[0x67452301,0xefcdab89|0,0x98badcfe|0,0x10325476];
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for(let offset=0;offset<padded.length;offset+=64){
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let [a,b,c,d]=h;
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for(let i=0;i<64;i++){
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let f,g;
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if(i<16){f=(b&c)|(~b&d);g=i;}
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else if(i<32){f=(d&b)|(~d&c);g=(5*i+1)%16;}
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else if(i<48){f=b^c^d;g=(3*i+5)%16;}
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else{f=c^(b|~d);g=(7*i)%16;}
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const shift=shifts[Math.floor(i/16)*4+i%4],sum=(a+f+constants[i]+view.getInt32(offset+g*4,true))|0;
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const next=(b+((sum<<shift)|(sum>>>(32-shift))))|0;a=d;d=c;c=b;b=next;
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}
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h=[(h[0]+a)|0,(h[1]+b)|0,(h[2]+c)|0,(h[3]+d)|0];
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}
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return h.map(n=>[0,8,16,24].map(s=>((n>>>s)&255).toString(16).padStart(2,'0')).join('')).join('');
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}
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async function blocks(file,progress=()=>{},valid=()=>true){
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const result=[];
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for(let offset=0;offset<file.size;offset+=4194304){
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if(!valid())throw Object.assign(Error('操作已取消'),{stale:true});
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result.push(md5(await file.slice(offset,offset+4194304).arrayBuffer()));progress(Math.min(file.size,offset+4194304),file.size);
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await new Promise(resolve=>setTimeout(resolve,0));
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}
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return result;
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}
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return {md5,blocks};
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})();
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if(typeof module!=='undefined')module.exports=ZhaoFileHash;
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