const MASK=0xffffffff;

function bytes2int32(arr){

	return arr.reduce((acc,b,i)=>acc|b<<(i*8));

}

function bytes2int32s(arr){

	let res=[];

	for(let i=0;i<arr.length;i+=4){

		res.push(bytes2int32(arr.slice(i,i+4)));

	}

	return res;

}

function int322bytes(x){

	let res=[];

	for(let i=0;i<4;i++){

		res.push(x&0xff);

		x>>>=8;

	}

	return res;

}

function int32s2bytes(arr){

	return arr.map(int322bytes).reduce((acc,bytes)=>acc.concat(bytes));

}

function bytes2hex(arr){

	return arr.map(x=>x.toString(16).padStart(2,"0")).join("");

}

function str2utf8(s){

	let res=[];

	let c=s.codePointAt(0);

	for(let i=0;c!==undefined;i++,c=s.codePointAt(i)){

		if(c<0x80){res.push(c);}

		else if(c<0x800){

			res.push(0b11000000|(c>>>6));

			res.push(0b10000000|(c&0b111111));

		}

		else if(c<0x10000){

			res.push(0b11100000|(c>>>12));

			res.push(0b10000000|((c>>>6)&0b111111));

			res.push(0b10000000|(c&0b111111));

		}

		else{

			res.push(0b11110000|(c>>>18));

			res.push(0b10000000|((c>>>12)&0b111111));

			res.push(0b10000000|((c>>>6)&0b111111));

			res.push(0b10000000|(c&0b111111));

		}

	}

	return res;

}