Excessive memory usage - packing long code crashes the browser

[xem]

I've encountered this problem a few times this month.
I have a long minified code (~3kb) containing a lot of repetitions, and when I try to regpack it in any browser, I get no output, and the browser crashes. (Fx, Chrome, Edge, all the same).

Here's the code I want to pack:

b.innerHTML="<textarea rows=40 cols=99 id=p>";oninput=function(){j=p.value;j=j.replace(/([^]*)eval\(_\)$/,function(a,m){eval(m);return _});c=[];s=[];r=[];for(d=e=f=g=h=o=0;o!=j;)o=j,"/"==(k=j.match(/['"\/]/))?(l=j.indexOf(k),n=j.slice(0,l+1),j=j[l+1].match(/[\/*]$/)?j.replace(/\/\/.*|\/\*[^]*?\*\//,function(a){c.push(a);return"@C"+e++ +"@"}):!n.match(/([\d\)\]\}]|true|false|null|undefined|this|@S\d+@)\s*(@C\d+@)*\s*\//im)&&n.match(/([-,;=><+%*&|^~!?!:\[\(]|delete|typeof|void|in|instanceof|of|case|delete|else|return|throw|yield|debugger|continue|break|throw|return|@D@|^)\s*(@C\d+@)*\s*\//m)?j.replace(/\/(\\\\|\\\/|[^\/])+?\/[gimuy]*/,function(a){r.push(a);return"@R"+g++ +"@"}):j.replace("/","@D@")):j="'"==k?j.replace(/'(\\\\|\\'|[^'])*?'/,function(a){s.push(a);return"@S"+h++ +"@"}):j.replace(/"(\\\\|\\"|[^"])*?"/,function(a){s.push(a);return"@S"+h++ +"@"});j=j.replace(/@D@/g,"/");j=j.replace(/ *([-+*%=&|:?<>^/]+) */g," $1 ");j=j.replace(/ *, */g,", ");j=j.replace(/}/g,"\n}");j=j.replace(/ *([;{}]|(case|default).*?:) */g,"$1\n");j=j.replace(/[\r\n]+ */g,"\n");j=j.replace(/for\s*\([^;]*?;[^;]*?;[^]/g,function(a){return a.replace(/\n/g,"").replace(/;/g,"; ")});j=j.replace(/.*?([{}])?\n/g,function(a,m){m+="";if("{"==m[0])return"  ".repeat(d++)+a;"}"==m[0]&&d--;return"  ".repeat(d)+a});j=j.replace(/\n+/g,"\n");j=j.replace(/@C(\d+)@/g,function(a,m){return c[m]});j=j.replace(/@S(\d+)@/g,function(a,m){return s[m]});j=j.replace(/@R(\d+)@/g,function(a,m){return r[m]});p.value=j};b.innerHTML="<textarea rows=40 cols=99 id=p>";oninput=function(){j=p.value;j=j.replace(/([^]*)eval\(_\)$/,function(a,m){eval(m);return _});c=[];s=[];r=[];for(d=e=f=g=h=o=0;o!=j;)o=j,"/"==(k=j.match(/['"\/]/))?(l=j.indexOf(k),n=j.slice(0,l+1),j=j[l+1].match(/[\/*]$/)?j.replace(/\/\/.*|\/\*[^]*?\*\//,function(a){c.push(a);return"@C"+e++ +"@"}):!n.match(/([\d\)\]\}]|true|false|null|undefined|this|@S\d+@)\s*(@C\d+@)*\s*\//im)&&n.match(/([-,;=><+%*&|^~!?!:\[\(]|delete|typeof|void|in|instanceof|of|case|delete|else|return|throw|yield|debugger|continue|break|throw|return|@D@|^)\s*(@C\d+@)*\s*\//m)?j.replace(/\/(\\\\|\\\/|[^\/])+?\/[gimuy]*/,function(a){r.push(a);return"@R"+g++ +"@"}):j.replace("/","@D@")):j="'"==k?j.replace(/'(\\\\|\\'|[^'])*?'/,function(a){s.push(a);return"@S"+h++ +"@"}):j.replace(/"(\\\\|\\"|[^"])*?"/,function(a){s.push(a);return"@S"+h++ +"@"});j=j.replace(/@D@/g,"/");j=j.replace(/ *([-+*%=&|:?<>^/]+) */g," $1 ");j=j.replace(/ *, */g,", ");j=j.replace(/}/g,"\n}");j=j.replace(/ *([;{}]|(case|default).*?:) */g,"$1\n");j=j.replace(/[\r\n]+ */g,"\n");j=j.replace(/for\s*\([^;]*?;[^;]*?;[^]/g,function(a){return a.replace(/\n/g,"").replace(/;/g,"; ")});j=j.replace(/.*?([{}])?\n/g,function(a,m){m+="";if("{"==m[0])return"  ".repeat(d++)+a;"}"==m[0]&&d--;return"  ".repeat(d)+a});j=j.replace(/\n+/g,"\n");j=j.replace(/@C(\d+)@/g,function(a,m){return c[m]});j=j.replace(/@S(\d+)@/g,function(a,m){return s[m]});j=j.replace(/@R(\d+)@/g,function(a,m){return r[m]});p.value=j}

I tried to pack it with all the options unchecked, but had the same problem.

Any idea?

Maybe the packer creates too many tokens and overflows out of ASCII and breaks everything?

(PS: I use the online packer regpack 4.0. Couldn't try command-line because... dunno how to install it)

(PS2: Strangely, this code, just a little shorter, packs well in ~957b:)

b.innerHTML="<textarea rows=40 cols=99 id=p>";oninput=function(){j=p.value;c=[];s=[];r=[];for(d=e=f=g=h=o=0;o!=j;)o=j,"/"==(k=j.match(/['"\/]/))?(l=j.indexOf(k),n=j.slice(0,l+1),j=j[l+1].match(/[\/*]$/)?j.replace(/\/\/.*|\/\*[^]*?\*\//,function(a){c.push(a);return"@C"+e++ +"@"}):!n.match(/([\d\)\]\}]|true|false|null|undefined|this|@S\d+@)\s*(@C\d+@)*\s*\//im)&&n.match(/([-,;=><+%*&|^~!?!:\[\(]|delete|typeof|void|in|instanceof|of|case|delete|else|return|throw|yield|debugger|continue|break|throw|return|@D@|^)\s*(@C\d+@)*\s*\//m)?j.replace(/\/(\\\\|\\\/|[^\/])+?\/[gimuy]*/,function(a){r.push(a);return"@R"+g++ +"@"}):j.replace("/","@D@")):j="'"==k?j.replace(/'(\\\\|\\'|[^'])*?'/,function(a){s.push(a);return"@S"+h++ +"@"}):j.replace(/"(\\\\|\\"|[^"])*?"/,function(a){s.push(a);return"@S"+h++ +"@"});j=j.replace(/@D@/g,"/");j=j.replace(/ *([-+*%=&|:?<>^/]+) */g," $1 ");j=j.replace(/ *, */g,", ");j=j.replace(/}/g,"\n}");j=j.replace(/ *([;{}]|(case|default).*?:) */g,"$1\n");j=j.replace(/[\r\n]+ */g,"\n");j=j.replace(/for\s*\([^;]*?;[^;]*?;[^]/g,function(a){return a.replace(/\n/g,"").replace(/;/g,"; ")});j=j.replace(/.*?([{}])?\n/g,function(a,m){m+="";if("{"==m[0])return"  ".repeat(d++)+a;"}"==m[0]&&d--;return"  ".repeat(d)+a});j=j.replace(/\n+/g,"\n");j=j.replace(/@C(\d+)@/g,function(a,m){return c[m]});j=j.replace(/@S(\d+)@/g,function(a,m){return s[m]});j=j.replace(/@R(\d+)@/g,function(a,m){return r[m]});p.value=j};b.innerHTML="<textarea rows=40 cols=99 id=p>";oninput=function(){j=p.value;j=j.replace(/([^]*)eval\(_\)$/,function(a,m){eval(m);return _});c=[];s=[];r=[];for(d=e=f=g=h=o=0;o!=j;)o=j,"/"==(k=j.match(/['"\/]/))?(l=j.indexOf(k),n=j.slice(0,l+1),j=j[l+1].match(/[\/*]$/)?j.replace(/\/\/.*|\/\*[^]*?\*\//,function(a){c.push(a);return"@C"+e++ +"@"}):!n.match(/([\d\)\]\}]|true|false|null|undefined|this|@S\d+@)\s*(@C\d+@)*\s*\//im)&&n.match(/([-,;=><+%*&|^~!?!:\[\(]|delete|typeof|void|in|instanceof|of|case|delete|else|return|throw|yield|debugger|continue|break|throw|return|@D@|^)\s*(@C\d+@)*\s*\//m)?j.replace(/\/(\\\\|\\\/|[^\/])+?\/[gimuy]*/,function(a){r.push(a);return"@R"+g++ +"@"}):j.replace("/","@D@")):j="'"==k?j.replace(/'(\\\\|\\'|[^'])*?'/,function(a){s.push(a);return"@S"+h++ +"@"}):j.replace(/"(\\\\|\\"|[^"])*?"/,function(a){s.push(a);return"@S"+h++ +"@"});j=j.replace(/@D@/g,"/");j=j.replace(/ *([-+*%=&|:?<>^/]+) */g," $1 ");j=j.replace(/ *, */g,", ");j=j.replace(/}/g,"\n}");j=j.replace(/ *([;{}]|(case|default).*?:) */g,"$1\n");j=j.replace(/[\r\n]+ */g,"\n");}

[Siorki]

Chrome grows to 750Mb then crashes.
It also happens with the original JsCrush and First Crush.

I recorded the same behavior on the prototype for v5.0 with a packer rewritten from scratch.
The debugger is able to unroll the loop up to the 1000th character before the crash.

[xem]

Thanks for the analysis. (and glad to hear about an upcoming 5.0)

If it can help, I got the same issue while I was packing the js1k entry "jsotopes":

this version worked fine:

y=x=l=9;for(i in e=']��]����]�]��v�,]�]��t,D,�_�]��t.�`�]�]�tF�a�]�]�uE�d��tF b��vE�d�]�]�tF f|]�DtF�h|��tG g�]�tH�f�_�I c�]��uH�h�^�tH ]�f|]��vG�]�j�tH�D�]�i�vG�]�j�tJ h��u|tH�f�`�J"h��vK�i��M f�^�DtL�h|]�t|J�D j�tL�l�M�D ]�j�vK�D�k�vJ�D k�wL�]�k�vL�D k�wN�m�M�D _�c�`�vL�]�l�N�D ]�j�vN�l�N�D k|]�P�j|`�O ]�i�]�O�p�L�D"l��Pm�_�L�D"]�l�Q�n��N�D ]�]�j�Q�]�q�R p�tR�r�P�D$]�]�i�U�]�l�.Q�D h�_�,tT�m�.Q�D"k�uV�l�]�W"h�^�tX�l�X�m�tV�n�U�,�]�i�Xm�S�D.�]�]�g�uV�D�j�E|N,D,D,D"g�tDtX�h�S,D�D�D ]�e�uZ�f�L-K�D�D ]�c�tJ-Q�f�H.O�D"]�a�uD,D.T�e�|E-S,D"d�u-Y�e�/U,D.],b�v,D,D,U�c|]�2F-M,D,!]�a|]�|0D,V�]�b�5Q,D�D ]�a�v/|,I,O�d�4N|G�D"]�b�t0L|N�]�c�1D,U,D c�,t.D-T�],c�D3D,L6^�,|4M3`�7D,D,D,D4],b�8D4g�C],d�=D,g�|A],b�;F,e�.D|1D,D0],`�.D,J,c�.H,D.],],_�F,E,G,],0�x-H,D2]x]|�-|E|J-_|^�yD,D,D,D,D0]x]x�D,M.^x,�x,x/D,D,D-x,z�,D,D,K,y-�x|x2x,x]y,�Dx3y-y�{,x,x,y-y,�3x.y,�x.x,z|x|.x�3~-x,x�0|-y|.�/|/x-},�0x.x,y|x�1x.x,�,x-|x,x,��-z�x.�.x,�/�-�,')if(s=e.charCodeAt(i),26>s)y++,l=x=l+s-18;else{m=25;for(j in f=[0,4,14,24,25,23,4,4,4])m+=f[j],s>m&&(z=s-m,c.fillStyle="#"+(7*m-32));c.fillRect(4*x,550-4*y,4*z,4);x+=z}

But this one, crashed the packer:

y=x=l=9;for(i in']��]����]�]��v�,]�]��t,D,�_�]��t.�`�]�]�tF�a�]�]�uE�d��tF b��vE�d�]�]�tF f|]�DtF�h|��tG g�]�tH�f�_�I c�]��uH�h�^�tH ]�f|]��vG�]�j�tH�D�]�i�vG�]�j�tJ h��u|tH�f�`�J"h��vK�i��M f�^�DtL�h|]�t|J�D j�tL�l�M�D ]�j�vK�D�k�vJ�D k�wL�]�k�vL�D k�wN�m�M�D _�c�`�vL�]�l�N�D ]�j�vN�l�N�D k|]�P�j|`�O ]�i�]�O�p�L�D"l��Pm�_�L�D"]�l�Q�n��N�D ]�]�j�Q�]�q�R p�tR�r�P�D$]�]�i�U�]�l�.Q�D h�_�,tT�m�.Q�D"k�uV�l�]�W"h�^�tX�l�X�m�tV�n�U�,�]�i�Xm�S�D.�]�]�g�uV�D�j�E|N,D,D,D"g�tDtX�h�S,D�D�D ]�e�uZ�f�L-K�D�D ]�c�tJ-Q�f�H.O�D"]�a�uD,D.T�e�|E-S,D"d�u-Y�e�/U,D.],b�v,D,D,U�c|]�2F-M,D,!]�a|]�|0D,V�]�b�5Q,D�D ]�a�v/|,I,O�d�4N|G�D"]�b�t0L|N�]�c�1D,U,D c�,t.D-T�],c�D3D,L6^�,|4M3`�7D,D,D,D4],b�8D4g�C],d�=D,g�|A],b�;F,e�.D|1D,D0],`�.D,J,c�.H,D.],],_�F,E,G,],0�x-H,D2]x]|�-|E|J-_|^�yD,D,D,D,D0]x]x�D,M.^x,�x,x/D,D,D-x,z�,D,D,K,y-�x|x2x,x]y,�Dx3y-y�{,x,x,y-y,�3x.y,�x.x,z|x|.x�3~-x,x�0|-y|.�/|/x-},�0x.x,y|x�1x.x,�,x-|x,x,��-z�x.�.x,�/�-�,')if(s=']��]����]�]��v�,]�]��t,D,�_�]��t.�`�]�]�tF�a�]�]�uE�d��tF b��vE�d�]�]�tF f|]�DtF�h|��tG g�]�tH�f�_�I c�]��uH�h�^�tH ]�f|]��vG�]�j�tH�D�]�i�vG�]�j�tJ h��u|tH�f�`�J"h��vK�i��M f�^�DtL�h|]�t|J�D j�tL�l�M�D ]�j�vK�D�k�vJ�D k�wL�]�k�vL�D k�wN�m�M�D _�c�`�vL�]�l�N�D ]�j�vN�l�N�D k|]�P�j|`�O ]�i�]�O�p�L�D"l��Pm�_�L�D"]�l�Q�n��N�D ]�]�j�Q�]�q�R p�tR�r�P�D$]�]�i�U�]�l�.Q�D h�_�,tT�m�.Q�D"k�uV�l�]�W"h�^�tX�l�X�m�tV�n�U�,�]�i�Xm�S�D.�]�]�g�uV�D�j�E|N,D,D,D"g�tDtX�h�S,D�D�D ]�e�uZ�f�L-K�D�D ]�c�tJ-Q�f�H.O�D"]�a�uD,D.T�e�|E-S,D"d�u-Y�e�/U,D.],b�v,D,D,U�c|]�2F-M,D,!]�a|]�|0D,V�]�b�5Q,D�D ]�a�v/|,I,O�d�4N|G�D"]�b�t0L|N�]�c�1D,U,D c�,t.D-T�],c�D3D,L6^�,|4M3`�7D,D,D,D4],b�8D4g�C],d�=D,g�|A],b�;F,e�.D|1D,D0],`�.D,J,c�.H,D.],],_�F,E,G,],0�x-H,D2]x]|�-|E|J-_|^�yD,D,D,D,D0]x]x�D,M.^x,�x,x/D,D,D-x,z�,D,D,K,y-�x|x2x,x]y,�Dx3y-y�{,x,x,y-y,�3x.y,�x.x,z|x|.x�3~-x,x�0|-y|.�/|/x-},�0x.x,y|x�1x.x,�,x-|x,x,��-z�x.�.x,�/�-�,'.charCodeAt(i),26>s)y++,l=x=l+s-18;else{m=25;for(j in f=[0,4,14,24,25,23,4,4,4])m+=f[j],s>m&&(z=s-m,c.fillStyle="#"+(7*m-32));c.fillRect(4*x,550-4*y,4*z,4);x+=z}

The only difference between both versions is that in the second one, I reuse the long string twice instead of assigning it to the variable e

[Siorki]

Can you please post base64-encoded strings for those two versions of jsotopes ? Control characters are not supported by GitHub's bugtracker.

[tomhodgins]

Hi guys!

I just tried running Maxime's string on my web server using Node on the CLI and I (eventually) was able to successfully output a packed file.

This doesn't seem to be a problem with RegPack, but rather just the limitations of the browser :)

[xem]

jsotopes short base64'd in utf-8:

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

jsotope long base64'd in utf-8:

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

as @tomhodgins says (thanks and hi tommy), I think it's just a super-resource-consuming loop done by the packer that the browser doesn't like...

EDIT: for the record, the packed code that tommy managed to get is only 941b.

[Siorki]

The crusher stage is memory intensive. I'll perform a few more tests but I reckon the only way to fix this is to completely rewrite the algorithm. This is due for v5.0, see #7. I'll keep an eye on performance while working on the new one.

Update : I did not get the crash when packing jsotopes (long version). Both FF and Chrome coughed a little and required 400 Mb yet they went through. Maybe a smaller configuration will not support it. But I have a slight idea of what happened - the longest repeating string is 905b long. The crusher built a dictionary with one instance of that string, but then it had 2 strings of 904b, 3 of 903b and so on. The memory usage is o(n²). The goal for #7 is to keep only the longest relevant strings.