Speed improvement

diff --git a/ppmtolss16 b/ppmtolss16
index b3925b7..341920a 100755 (executable)
--- a/ppmtolss16
+++ b/ppmtolss16
@@ -109,26 +109,26 @@ sub getrgb($) {
     my($form) = @_;
     my($rgb,$r,$g,$b);
 
-    if ( $form eq 'P6' ) {
+    if ( $form == 6 ) {
        # Raw PPM, most common
        return undef unless ( read(STDIN,$rgb,3) == 3 );
        return unpack("CCC", $rgb);
-    } elsif ( $form eq 'P3' ) {
+    } elsif ( $form == 3 ) {
        # Plain PPM
        $r = get_numeric_token();
        $g = get_numeric_token();
        $b = get_numeric_token();
        return ($r,$g,$b);
-    } elsif  ( $form eq 'P5' ) {
+    } elsif  ( $form == 5 ) {
        # Raw PGM
        return undef unless ( read(STDIN,$rgb,1) == 1 );
        $r = unpack("C", $rgb);
        return ($r,$r,$r);
-    } elsif ( $form eq 'P2' ) {
+    } elsif ( $form == 2 ) {
        # Plain PGM
        $r = get_numeric_token();
        return ($r,$r,$r);
-    } elsif ( $form eq 'P4' ) {
+    } elsif ( $form == 4 ) {
        # Raw PBM
        if ( !$getrgb_leftover_bit_cnt ) {
            return undef unless ( read(STDIN,$rgb,1) == 1 );
@@ -140,7 +140,7 @@ sub getrgb($) {
        $getrgb_leftover_bit_cnt--;
        
        return ($r,$r,$r);
-    } elsif ( $form eq 'P1' ) {
+    } elsif ( $form == 1 ) {
        # Plain PBM
        my($ch);
        
@@ -215,14 +215,15 @@ foreach $arg ( @ARGV ) {
 }
 
 $form = get_token();
-die "$0: stdin is not a PNM file" if ( $form !~ /^P[1-6]$/ );
+die "$0: stdin is not a PNM file" if ( $form !~ /^P([1-6])$/ );
+$form = $1+0;
 
 $xsize = get_numeric_token();
 $ysize = get_numeric_token();
-if ( $form =~ /^P[2356]$/ ) {
-    $maxcol = get_numeric_token();
-} else {
+if ( $form == 1 || $form == 4 ) {
     $maxcol = 255;             # Internal convention
+} else {
+    $maxcol = get_numeric_token();
 }
 $maxmult = 64/($maxcol+1);     # Equal buckets conversion