140bytes challenges

Re: 140bytes challenges

LeverOne — Thu, 26 Jan 2012 04:07:25 -0600

// 109

function(a,b,c,d,e){for(d=e='';a[d|0]||(b='=',d%1);e+=b[63&c>>8-d%1*8])c=c<<8|a.charCodeAt(d-=-.75);return e}

Re: 140bytes challenges

LeverOne — Tue, 14 Jun 2011 01:24:48 -0500

Base64 decoder

116:

function(a,b,c,d,e){for(e='';~(c=c<<6|b.indexOf(a[d|=0]));d++%4?e+=String.fromCharCode(c>>(-d&3)*2&255):0);return e}

//added later
115:

function(a,b,c,d,e){for(e='';~(c=c<<6|b.indexOf(a[d|=0]));d++%4?e+=String.fromCharCode(c>>(d*6&6)&255):0);return e}

Notes:

1. Why not "search" ?

1) alert("+".search("+"));
2) ~(c=c<<6|b.search(a[d|=0])) <-- obviously endless loop if input data w/o "=", as we see in older versions here [gist.github.com]

2. It's still the incorrect decoder.

Quote
http://tools.ietf.org/html/rfc2045

Any characters outside of the base64 alphabet are to be ignored in
base64-encoded data.

Join! :)

Correct decoder

130:

function(a,b,c,d,e,f){f=e='';for(d in a)~(d=b.indexOf(a[+d]))&&(c=d|c<<6,f++%4)?e+=String.fromCharCode(c>>(f*6&6)&255):0;return e}

Notes:

1. a[+d] - to exclude custom prototypic methods/properties.

2.

Quote
http://tools.ietf.org/html/rfc2045
Because it is used only for padding at the end of the data, the
occurrence of any "=" characters may be taken as evidence that the
end of the data has been reached (without truncation in transit).

In this implementation "=" character is not regarded as an end of the data. Therefore, input "YWJ=j" will be decoded as "abc".

Example:

alert(b64decode('YW %-) Jj','ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'))

To encode/decode UTF-8 string you can use this solution:

alert(decodeURI(escape(b64decode('0YLQtdGB0YI=','ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'))))

alert(b64encode(unescape(encodeURI('\u0442\u0435\u0441\u0442')),'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'))

[ecmanaut.blogspot.com]

Re: 140bytes challenges

noma — Fri, 10 Jun 2011 13:25:01 -0500

Wow,
just amazing, really really nice

Re: 140bytes challenges

Gareth Heyes — Fri, 10 Jun 2011 10:57:29 -0500

Every time I open this thread I can't believe it. Nice work all of you

Re: 140bytes challenges

LeverOne — Fri, 10 Jun 2011 08:35:07 -0500

Jonas, you unleashed a few knots in the excellent work by noma, well done!

another:

a[d++]||(b='=')&&e --> a[d++]||(b='=',e)

// 110

function(a,b,c,d,e,f){for(d=f='';e&=3,a[d++]||(b='=',e);f+=b[63&c>>++e*2])c=c<<8|a.charCodeAt(d-=!e);return f}

Re: 140bytes challenges

Jonas Magazinius — Thu, 09 Jun 2011 22:13:47 -0500

Back from my short vacation!

First off, fantastic work noma! I was trying to do something similar before, but never got it quite right. Your innovation inspired me to cut it down even further:

113 chars:
function(a,b,c,d,e,f){for(d=e=f='';a[d++]||(b='=')&&e;e&=3)f+=b[63&(c=c<<8|a.charCodeAt(d-=!e++))>>e*2];return f}

Actually 112 chars:
function(a,b,c,d,e,f){for(d=f='';e&=3,a[d++]||(b='=')&&e;)f+=b[63&(c=c<<8|a.charCodeAt(d-=!e))>>++e*2];return f}

Re: 140bytes challenges

jedschmidt — Thu, 09 Jun 2011 07:58:57 -0500

going, going...

(the work in this thread has been inspiring, btw.)

Re: 140bytes challenges

noma — Sat, 04 Jun 2011 15:37:43 -0500

117:

function(c,d,b,a,g,e){for(b=a=e="";c[+b]||a;d=c[b++]?d:"=")e+=d[63&(g=g<<8|c.charCodeAt(b-=!(a=a+2&7)))>>a];return e}

Re: 140bytes challenges

LeverOne — Fri, 03 Jun 2011 16:54:36 -0500

@noma

1. nice move!
2. you have 114.
3. and yes, it was fix for issue №1 only. Full fix for single loop version looks like this:

function(a,b,c,e,i,j){for(e=i='';!j|i%3?!!a[+i]|i%3|(c=j*c<<6|a.charCodeAt(i++,j=4)):e+=a[!e+i-j--]?b[c>>j*6&63]:'=';);return e}

upd: 126

function(a,b,c,e,i,j){for(e=i='';!j|i%3?j|(c=j*c<<6|a.charCodeAt(i++,j=4))||a[i-1]:e+=a[!e+i-j--]?b[c>>j*6&63]:'=';);return e}

upd: 120

function(a,b,c,e,i,j){for(e=i='';a[+i]||j;)!j|i%3?c=c<<8|a.charCodeAt(i++,j=4):e+=a[!e+i-j--]?b[c>>j*6&63]:'=';return e}

Re: 140bytes challenges

noma — Thu, 02 Jun 2011 21:30:28 -0500

115 (again):

function(a,b,c,e,i,j){for(e=i='';!j|i%3?c=c*j<<6|a.charCodeAt(i++,j=4):e+=a[!e+i-j--]?b[c>>j*6&63]:'=';);return e}

thx for the little welcome :)

It will be interesting to see when no further byte can be squeezed out

---

Hmmmm, none of the single loop versions can handle 0-input strings like "\0", "\0\0", "\0\0\0", ....

Re: 140bytes challenges

LeverOne — Thu, 02 Jun 2011 19:38:34 -0500

116:

function(a,b,c,d,e,f){for(e=f='';!d|f%3?c=d*c/d<<8|a.charCodeAt(f++,d=4):e+=a[!e+f-d--]?b[c>>d*6&63]:'=';);return e}

aaand!

Re: 140bytes challenges

LeverOne — Thu, 02 Jun 2011 19:14:40 -0500

118:

function(a,b,c,d,e,f){for(e=f='';!d|f%3?c=(d?c:0)<<8|a.charCodeAt(f++,d=4):e+=a[!e+f-d--]?b[c>>d*6&63]:'=';);return e}

@noma

Welcome :)

Re: 140bytes challenges

Gareth Heyes — Thu, 02 Jun 2011 19:03:48 -0500

@noma

Welcome to the forums, assuming that code works you're awesome! Nice work

Re: 140bytes challenges

noma — Thu, 02 Jun 2011 16:39:34 -0500

120:

function(a,b,c,d,e,f){e=f='';for(;!d|f%3?c=c<<8|a.charCodeAt(f++,d=4):e+=a[!e+f-d--]?b[c>>d*6&63]:'=';d?0:c=0);return e}

119:

function(a,b,c,d,e,f){for(e=f='';!d|f%3?c=c<<8|a.charCodeAt(f++,d=4):e+=a[!e+f-d--]?b[c>>d*6&63]:'=';c=d?c:0);return e}

Re: 140bytes challenges

LeverOne — Thu, 02 Jun 2011 16:20:02 -0500

115 chars version has the following issues:

1. 'abc' --> 'YWJjA===' (extra iteration if the input string is divisible by 3)
2. '\x00abc' --> '' (null character caused c = 0 in the first iteration)
3. 'abc\0\0\0\x00abc' --> 'YWJjAAAA' (same problem via 4 iteration)

This is variants to fix only for 1.

// 125

function(a,b,c,d,e,f){e=f='';for(;!d--|f%3?c=a[f]||~d?c<<8|a.charCodeAt(f++,d=4):0:e+=a[f-d-!!e]?b[c>>d*6&63]:'=';);return e}

// 122

function(a,b,c,d,e,f){e=f='';for(;!d--|f%3?c=c<<(~d?8:16)|a.charCodeAt(f++,d=4):e+=a[f-d-!!e]?b[c>>d*6&63]:'=';);return e}

function(a,b,c,d,e,f){e=f='';for(;!d--|f%3?c=c<<8|a.charCodeAt(f++,d=4):e+=a[f-d-!!e]?b[c>>(d?d:c=0)*6&63]:'=';);return e}

// 121

function(a,b,c,d,e,f){e=f='';for(;!d--|f%3?c=c<<8|a.charCodeAt(f++,d=4):e+=a[f-d-!!e]?b[c>>d*6&63]:'=';d?0:c=0);return e}

As we see it less than we need to shorten 123.

Quote

How about making it without the lookup table?

In my opinion is more important to add support for 2-bytes characters.
Or do base64decode (which is slightly more complicated due to the fact that the two methods are necessary "search" + "String.fromCharCode")

Re: 140bytes challenges

Gareth Heyes — Wed, 01 Jun 2011 12:36:02 -0500

How about making it without the lookup table?

Something like:
c=(c<27?c+65:c<53?c+70:c<57?c-4:47);

Which could obviously be shorter but you get the idea

Re: 140bytes challenges

Jonas Magazinius — Wed, 01 Jun 2011 12:17:01 -0500

This is still work in progress, but I have to share this.

Single loop, incorrect padding and can't handle null chars, but it's beautiful!

99 chars:
function(a,b,c,d,e,f){for(e=f='';!d--||f%3?c=c<<8|a.charCodeAt(f++,d=4):e+=b[c>>d*6&63];);return e}

Single loop, correct padding, but can't handle null chars:

115 chars:
function(a,b,c,d,e,f){for(e=f='';!d--||f%3?c=c<<8|a.charCodeAt(f++,d=4):e+=a[f-d-!!e]?b[c>>d*6&63]:'=';);return e}

Now fellow sla.ckers, I think this can be corrected and reduced even further. Let's do this together!

Re: 140bytes challenges

Skyphire — Wed, 01 Jun 2011 05:29:56 -0500

Another easy way of getting the binary bit pattern:

s = 'hello',k = '';

for(i in s) k += '0'+s.charCodeAt(i).toString(2);

Then simply do a modulo 6 in the base64 char index.

Re: 140bytes challenges

LeverOne — Tue, 31 May 2011 22:05:42 -0500

Previous versions of the code (123,121,120) contains an error: if the input string is empty, they return "A===". Fixed version again 123 bytes.

function(a,b,c,d,e,f){for(e=f='';a&&b[d=4];)for(c=c<<8|a.charCodeAt(f++);f%3?0:d--;b=a[f-d]?b:'=')e+=b[c>>d*6&63];return e}

Re: 140bytes challenges

LeverOne — Tue, 31 May 2011 19:11:19 -0500

120:

function(a,b,c,d,e,f){for(e=f='';b[d=4];)for(c=c<<8|a.charCodeAt(f++);f%3?0:d--;b=a[f-d]?b:'=')e+=b[c>>d*6&63];return e}

Re: 140bytes challenges

LeverOne — Tue, 31 May 2011 18:49:14 -0500

121:
function(a,b,c,d,e,f){for(e=f='';b[1];d=4)for(c=c<<8|a.charCodeAt(f++);f%3?0:d--;b=a[f-d]?b:'=')e+=b[c>>d*6&63];return e}

Re: 140bytes challenges

Gareth Heyes — Tue, 31 May 2011 18:19:23 -0500

:O

Amazing!

Re: 140bytes challenges

Jonas Magazinius — Tue, 31 May 2011 17:26:02 -0500

Ok, I think I've reached a fixpoint for now.

No cheating, no leaking, merged two loops.

123 chars:
function(a,b,c,d,e,f){for(e=f='';b[1];d=4)for(c=c<<8|a.charCodeAt(f++);!(f%3)&&d--;b=a[f-d]?b:'=')e+=b[c>>d*6&63];return e}

Re: 140bytes challenges

LeverOne — Mon, 30 May 2011 14:56:07 -0500

Quote

But I managed to reduce it a bit

Only when you change the rules. :)

Quote

and map string ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/

How much do you have if you do not change the rules?

upd: I guess that 130. Nice!

Re: 140bytes challenges

Jonas Magazinius — Mon, 30 May 2011 14:43:03 -0500

@LeverOne: Brilliant work as usual! But I managed to reduce it a bit..

129 chars:
function(a,b){for(var c=d=e=f='';a[+f];){for(;c=c<<8|a.charCodeAt(f++),f%3;);for(d=4;d--;)e+=b[a[f-d-!!e]?c>>d*6&63:64]}return e}

Re: 140bytes challenges

LeverOne — Mon, 30 May 2011 13:23:13 -0500

@Wisec

PoC? :)

-------------
^
| At first I took it as а "3 bytes shorter version". LOL
-------------

UPDATE 06/11/2001

Here's the history of base64 encoder outside sla.ckers

1. [gist.github.com] by bytespider

158, '=' - in map with index 64

Quote

function(a,b,c,d,e,f,g,h){h="";for(d=0;a[d];h+=b[e>>2]+b[e<<4&63|f>>4]+b[f<<2&63|g>>6||64]+b[g&63||64])for(c=4;c<7;)arguments[c++]=a.charCodeAt(d++);return h}

2. [gist.github.com] by aemkei

140, w/o padding, !IE

Quote

function(a,b,c,d,e,f,g){for(g=c=e="";(d=a.charCodeAt(g))&&(c+=/.{8}$/(1e7+d.toString(2))),f=c.substr(g++*6,6);)e+=b[parseInt(f,2)];return e}

3. [gist.github.com] by nignag <-- possibly noma

A lot of bright ideas in revisions; padding as an independent variable in the function declaration.

Re: 140bytes challenges

Wisec — Mon, 30 May 2011 13:04:07 -0500

we <3 LeverOne :)

Re: 140bytes challenges

LeverOne — Sat, 28 May 2011 01:27:00 -0500

RULES: [github.com]

Quote

Encode: a function that takes the string input and map string ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/, return the base64 encoding. Bonus points for proper "=" padding. [UPDATE] Much progress has been made here, but it's still not cross-browser due to lack of executable RegExps in IE.

b64encode=

function(a,b){for(var c=d=e=f='';c=0,a[+f];){for(d=3;d--;c|=a.charCodeAt(f++)<>d*6&63]:'='}return e}  
// 137

/* or
function(a,b,c,d,e,f){for(e=f='';c=0,a[+f];){for(d=3;d--;c|=a.charCodeAt(f++)<>d*6&63]:'='}return e}  
// 137
*/

alert(b64encode('a\r\nab','ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'))

1. Correct padding for 8- and 16-bits input.
2. Any chars within 0-255 (dec).
3. Leakage in global scope is eliminated (using "var" etc.)
4. IE 8-9, Chrome, Safari, Firefox, Opera

LeverOne

Re: 140bytes challenges

Gareth Heyes — Wed, 25 May 2011 12:42:00 -0500

Here's a FF one for fun:

('0'+[''.charCodeAt.call(x,i).toString(2)for(i in x='abc')].join(0)).replace(/.{1,6}/g,function(c)b[parseInt(c,2)])

Re: 140bytes challenges

Jonas Magazinius — Wed, 25 May 2011 12:31:36 -0500

Ok, here's one. Not very optimized, but handles all input with correct padding:

y='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
x=function(a)a.charCodeAt();
'\xff\xff\xff'.replace(/(.)(.)?(.)?/g,function(_,a,b,c)y[x(a)>>2]+y[63&x(a)<<4|x(b)>>4]+(b?y[63&x(b)<<2|x(c)>>6]:'=')+(c?y[63&x(c)]:'='))