Formatting texts for cat|less

<?php

$input  = "book.in";
$output = "book.out";
$chars_per_line = 60;
$margin_left  = 0;
$margin_right = 0;
$red_line     = 5;

define("NBSP","~");

function is_punct($char){
    return $char=="," || $char=="." || $char=="-" || $char=="—" || $char==";" || $char==":" || $char=="!" || $char=="?" || $char==")";
    }

function is_space($char){
    return $char==" " || $char=="\t" || $char=="\r" || $char=="\n";
    }

function sp($n){
    return str_repeat(" ",$n);
    }

function crop($line,$len){
    if(mb_strlen($line)<=$len)
        return $line;

    $line=mb_substr($line,0,$len);

    $i=mb_strlen($line)-1;
    while($i>=2 && !is_space(mb_substr($line,$i,1)) )
        $i--;
    $line=trim(mb_substr($line,0,$i));

    return $line;
    }

function justify($line,$len){
    $line=trim($line);
    $words=mb_split("\s+",$line);

    $total=0;
    $deficite=$len;
    $factors=array();
    for($i=0;$i<count($words)-1;$i++){
        $this_word=$words[$i];
        $next_word=$words[$i+1];

        $l1=mb_strlen($this_word);
        $l2=mb_strlen($next_word);

        $factor = is_punct(mb_substr($this_word,-1,1)) ? max($l1-1,$l2) : min($l1,$l2);

        $total+=$factor;
        $deficite -= $l1+1;
        $factors[$i]=$factor;
        }
    $deficite -= mb_strlen($words[count($words)-1]);

    $ret="";
    for($i=0;$i<count($words)-1;$i++){
        $n=round($deficite*$factors[$i]/$total);
        $ret.=$words[$i].sp($n+1);
        $deficite-=$n;
        $total-=$factors[$i];
        }
    $ret.=sp($deficite).$words[count($words)-1];

    return $ret;
    }


function preprocess($line){
    $line=mb_ereg_replace("(\s|".NBSP.")([а-яёА-ЯЁ]|Не|Ни|не|ни)\s+","\\1\\2".NBSP,$line);
    $line=mb_ereg_replace("(\s|".NBSP.")([а-яёА-ЯЁ]|Не|Ни|не|ни)\s+","\\1\\2".NBSP,$line);
    $line=mb_ereg_replace("(\s|".NBSP.")([а-яёА-ЯЁ]|Не|Ни|не|ни)\s+","\\1\\2".NBSP,$line);
    return $line;
    }

function postprocess($line){
    $line=mb_ereg_replace(NBSP," ",$line);
    return $line;
    }

function process($line,$len,$spaces){
    global $outfile;
    $line = trim($line);
    $line = preprocess($line);
    $subline = postprocess(crop($line,$len));
    $line = mb_substr($line,mb_strlen($subline));
    if($line){
        $char=mb_substr($subline,-1,1);
        if(is_punct($char))
            $len++;
        $subline = justify($subline,$len);
        }
    fwrite($outfile,$spaces.$subline."\n");
    return $line;
    }

$len     = $chars_per_line-$margin_right-$margin_left;
$len1    = $len-$red_line;
$spaces  = sp($margin_left);
$spaces1 = sp($margin_left+$red_line);

mb_internal_encoding("UTF-8");

$infile  = fopen($input,"r");
$outfile = fopen($output,"w");

$i=0;

while(($line=fgets($infile))!==FALSE){
    $line=process($line,$len1,$spaces1);
    while($line){
        $line=process($line,$len,$spaces);
        }
    }

fclose($infile);
fclose($outfile);

?>