Macintosh C compiler / GREP library?

I have two needs, both related.

I am looking for a good (free) c/c++ compiler for mac, and aslo looking for a
library that uses grep commands.

Anyone got tips?

#!/usr/bin/perl -w

MPEG 2 PS VOB file on stdin -> descrambled output on stdout arguments: title

key bytes in least to most-significant order

$='while(read+STDIN,$,2048){$a=29;$b=73;$c=142;$t=255;@t=map{$_%16or$t^=$c^=(

$m=(11,10,116,100,11,122,20,100)[$/16%8])&110;$t^=(72,@z=(64,72,$a^=12*($%16

-2?0:$m&17)),$b^=$%64?12:0,@z)[$%8]}(16…271);if((@a=unx"C*",$_)[20]&48){$h

=5;$=unxb24,join"",@b=map{xB8,unxb8,chr($^$a[–$h+84])}@ARGV;s/…$/1$&/;$

d=unxV,xb25,$_;$e=256|(ord$b[4])<<9|ord$b[3];$d=$d>>8^($f=$t&($d>>12^$d>>4^

$d^$d/8))<<17,$e=$e>>8^($t&($g=($q=$e>>14&7^$e)^$q*8^$q<<6))<<9,$=$t[$]^

(($h>>=8)+=$f+(~$g&$t))for@a[128…$#a]}print+x"C*",@a}’;s/x/pack+/g;eval