What does this code implement?

on 25 Jul 2007 by Mukund (@muks)

char*a=" $#,.';:\n\t",*s="\0000\a\t\031\r1\020\021\005",*d="\215\266\333\
S3\032\004\321\232L\32176\233\346;\346\030J~G\200\317\251\373O\001\237h\
\3371C\233\317\211\274\317\371\023\364\235\033\314\377\221\276a\360\371\
\f~\341\342\303\326\361\277\353~O\207\307h\337\365\277\"\034o\304yg\b\
\3146\317\333|\033\355\003\016\033\306\377\3411\264\004\375\0336\202a\
\242~\3061",i,j,r=0,b=0;main(){for(i=0;i<98;i++){for(;;){r<<=1;r|=(*(d+i)
>>(7-b++))&1;for(j=0;j<10;j++) if(*(s+j)==r){putchar(*(a+j));r=0;break;}
if(b>=8){b=0;break;}}}}

Download main.c.

Eek! Look at all that terrible code. Anyway, main() implements a well-known algorithm. Can you figure out what it is?

Note: When you compile this code, make sure it's indented at column 0, i.e., no leading spaces, or they'll become part of the d string.