PHP code for simple compression of English strings

//replacement encrypted replacement from the previous version
function compress_func($match) {return strlen($match[0]).$match[0]{0 };}
function uncompress_func($match) {return str_repeat($match[2], $match[1]);}
function compress($str) {
 $i = 0;
 $pattern = array();
 while(isset($replacement{$i})) array_push($pattern, "/".$replacement{$i++}."{2,}/");
 return preg_replace_callback($pattern, "compress_func", $ str);
 }
function uncompress($str) {
 return preg_replace_callback("/(d+)(w)/", "uncompress_func", $str);
}
?> ;

Now I will share the code for awk to implement string compression. AWK, universal format compressed string:

#!/bin/awk
function compress(str, _ARGVEND_, str_out, str_len, i, s, l) {
 str_out = "";
 str_len = length(str);
 s = "" ;
 l = 1;
 for(i =1; i <= str_len; i++) {
 if(substr(str, i, 1) == s) l++;
 else {
 if(s != "" ) {
 if(l > 1) str_out=str_out""l
 str_out=str_out""s;
 }
 s = substr(str, i, 1);
 l = 1;
 }
 }
 return str_out ;
}
function uncompress(str, _ARGVEND_, str_out, str_len, i, c) {
 str_out = "";
 str_len = length(str);
 for(i =1; i <= str_len; i++) {
 c = 0;
 while(substr(str, i, 1)~/[0-9]/) {
 c = c*10+substr(str, i, 1);
 i++;
 }
 if( c < 1) c = 1;
 while(c--) str_out = str_out""substr(str, i, 1);
 }
 return str_out;
}